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Zanubrutinib, a highly selective Bruton tyrosine kinase inhibitor, was evaluated in a phase 1/2 study in patients with various B-cell malignancies. In the subgroup of patients with relapsed/refractory (R/R) mantle cell lymphoma (MCL), zanubrutinib was administered as 160 mg twice daily (n = 14), 320 mg once daily (n = 18), or ≤160 mg total dose (n = 5). Herein, we report results for patients receiving a total daily dose of 320 mg (N = 32). Median study follow-up was 18.8 months. Eighteen patients discontinued treatment, 10 because of progressive disease and 8 because of adverse events (AEs); 1 AE (peripheral edema) was considered to be related to zanubrutinib treatment. The most common AEs were diarrhea (43.8%), contusion (37.5%), constipation (31.3%), and upper respiratory tract infection (31.3%). Infection was the most commonly reported AE of interest (18.8% of patients experienced grade ≥3 infection). At least 1 AE of grade ≥3 was reported in 59.4% of patients; grade ≥3 AEs that were reported in >2 patients were anemia (12.5%), pneumonia (9.4%), and myalgia (9.4%). Overall response rate was 84%, with 25% achieving a complete response. Median duration of response was 18.5 months. Median progression-free survival (PFS) was 21.1 months. Zanubrutinib was well tolerated and demonstrated activity in patients with R/R MCL. The trial is registered at www.clinicaltrials.gov as #NCT02343120.

Blastoid mantle cell lymphoma is characterized by highly aggressive features and a dismal clinical course. These blastoid and pleomorphic variants are defined by cytomorphological features, but the criteria are somewhat subjective. The diagnosis may be supported by a high cell proliferation based on the Ki-67 labeling index. Recent analyses have shown that the Ki-67 index overrules the prognostic information derived from the cytology subtypes. Nevertheless, genetic analysis suggests that blastoid and pleomorphic variants are distinct from classical mantle cell lymphoma. In clinical cohorts, the frequency of these subsets varies widely but probably represents ∼10% of all cases. Chemotherapy regimens commonly used in mantle cell lymphoma, such as bendamustine, rarely achieve prolonged remissions when given at the dosage developed for classical variants of the disease. Thus, high-dose cytarabine–containing regimens with high-dose consolidation may be generally recommended based on the more aggressive clinical course in these patients. However, even with these intensified regimens, the long-term outcome seems to be impaired. Thus, especially in this patient subset, allogeneic transplantation may be discussed at an early time point in disease management. Accordingly, targeted approaches are warranted in these patients, but clinical data are scarce. Ibrutinib treatment results in high rates of responses, but the median duration of remission is

Background: Mantle cell lymphoma (MCL) accounts for approximately 5-7% of non-Hodgkin lymphomas (NHL). Bruton's tyrosine kinase (BTK) inhibitors, eg ibrutinib, are indicated for treatment of adults with MCL who have received ≥1 prior therapy. Primary and acquired resistance to ibrutinib is common and linked with poor outcomes, and remains an unmet medical need. Parsaclisib, a potent, highly-selective, next-generation PI3Kδ inhibitor, demonstrated clinical activity in patients (pts) with relapsed or refractory (R/R) NHL. We report preliminary results for parsaclisib monotherapy in a cohort of pts with R/R MCL who were previously treated with ibrutinib in the open-label, phase 2 study CITADEL-205 (NCT03235544). Methods: Pts must be ≥18 years of age with pathologically confirmed MCL, R/R disease to the most recent treatment, documented cyclin D1 overexpression or t(11;14) translocation, have Eastern Cooperative Oncology Group performance status (ECOG PS) ≤2, and received 1 to 3 prior systemic treatments (including ibrutinib). Prior treatment with PI3Ki was prohibited. Pts were allocated to receive parsaclisib 20 mg once daily (QD) for 8 weeks followed by either 20 mg once weekly (weekly-dosing group [WG]) or 2.5 mg QD (daily-dosing group [DG]). Prophylaxis for Pneumocystis jirovecii pneumonia (PJP) was required. Objective response rate (ORR) was the primary endpoint; complete response rate (CRR), duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety and tolerability were secondary endpoints. All radiology-based endpoints were based on independent review. Results: From October 2017 to January 17, 2020 (data cut-off), 47 pts were treated (WG, n = 12; DG, n = 35). Enrollment is ongoing. At cut-off, 70% of pts had discontinued treatment, most commonly due to progressive disease (62%). Median exposure (range) was 2.2 (0.1-18.0) months. Median age was 70 years and 79% of pts were men. Median time since initial diagnosis was 4.7 years. Most pts (85%) had ECOG PS ≤1 and 51% had high-risk MCL International Prognostic Index. The median number of prior systemic therapies was 3; 38% of pts had prior hematopoietic stem cell transplant, and 38% were refractory to most recent systemic therapy. At data cut-off, 46 pts were evaluable for efficacy, including 12 in WG and 34 in DG (Table). Median follow-up (range) for this population was 10.2 months (1.5-25.9) overall and 7.6 months (1.5-25.9) for DG. ORR (95% confidence interval [CI]) and CRR were 28.3% (16.0-43.5) and 2.2%, respectively in all evaluable pts, and 35.3% (19.7-53.5) and 2.9%, respectively in DG. Median time to complete or partial response was 7.6 weeks. Median DOR (95% CI) was 7.3 months (0.2-not estimable) among all responders and 3.7 months (0.2-7.3) for DG. Median PFS (95% CI) was 3.65 months (1.9-3.9) overall and 3.65 months (1.9-5.5) for DG. Among 47 safety-evaluable pts, most common treatment-emergent adverse events (TEAEs) occurring in >10% of pts were anemia (19.1%), diarrhea (19.1%), neutropenia (14.9%), asthenia and cough (12.8% each), decreased appetite, dyspnea, fatigue, pyrexia and rash (10.6% each). Most common grade ≥3 TEAEs reported in ≥5% of pts included anemia (12.8%), neutropenia (10.6%), thrombocytopenia and rash (6.4% each). TEAEs leading to dose interruption or reduction occurred in 31.9% and 2.1% of pts, respectively. TEAEs leading to treatment discontinuation occurred in 2 (4.3%) pts (diarrhea and colitis). Serious TEAEs reported in ≥2 pts were diarrhea, dyspnea, peripheral swelling and pneumonia (4.3% each). Two pts experienced fatal TEAEs (one pt had general physical health deterioration and respiratory tract infection, deemed not related to treatment; one pt had pneumonia, neutropenia, and septic shock, deemed related to treatment and disease progression). New or worsening grade ≥3 laboratory test values of clinical interest occurring in ≥5% of pts included decreased neutrophils (14.9%), platelets (10.6%), and hemoglobin (8.5%); there were no grade ≥3 increases in alanine/aspartate aminotransferase. Conclusion: Preliminary efficacy data indicate that parsaclisib monotherapy is clinically active in this difficult-to-treat patient population. Treatment with parsaclisib had an acceptable safety profile and was generally well tolerated. Updated study results will be presented. Disclosures Zinzani: EUSA Pharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kyowa Kirin: Consultancy, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Immune Design: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Sandoz: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Servier: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Portola: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celltrion: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Verastem: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Immune Design: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen-Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kirin Kyowa: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; TG Therapeutics, Inc.: Honoraria, Speakers Bureau; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; Eusapharma: Consultancy, Speakers Bureau. Delwail:Amgen: Consultancy. Paneesha:Bristol-Myers Squibb: Honoraria; Celgene: Honoraria; Gilead: Honoraria; Janssen: Honoraria; AbbVie: Honoraria. Rule:AstraZeneca: Consultancy; Celgene: Consultancy; Celltrion: Consultancy; Janssen Oncology: Consultancy, Research Funding, Speakers Bureau; Roche Pharma AG: Consultancy, Research Funding. Martin Garcia-Sancho:Roche, Celgene, Janssen, Servier, Gilead: Honoraria; Celgene, Eusa Pharma, Gilead, iQuone, Kyowa Kirin, Roche, Morphosys: Consultancy. Salles:Amgen: Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Gilead Sciences: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Roche/Genentech: Consultancy, Honoraria, Other: Travel expenses, Research Funding; Servier: Consultancy, Honoraria; Acerta Pharma: Consultancy; Kite Pharma: Consultancy; Merck: Consultancy, Research Funding; Novimmune: Consultancy; Pfizer: Consultancy; Sanofi: Other. Sancho:Sandoz: Consultancy; Celltrion: Consultancy; Roche: Consultancy, Honoraria; Takeda: Honoraria; Novartis: Consultancy, Honoraria; Kern-Pharma: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Bristol-Myers Squibb: Honoraria. Zheng:Incyte: Current Employment, Current equity holder in publicly-traded company. DeMarini:Incyte Corporation: Current Employment, Current equity holder in publicly-traded company. Jiang:Incyte Corporation: Current Employment, Current equity holder in publicly-traded company. Mehta:Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Gelgene/BMS: Research Funding; Affimed: Research Funding; Merck: Research Funding; Kite/Gilead: Research Funding; Juno Parmaceuticals/BMS: Research Funding; Innate Pharmaceuticals: Research Funding; Oncotartis: Research Funding; Roche-Genentech: Research Funding; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; fortyseven Inc/Gilead: Research Funding; Takeda: Research Funding.

Introduction: Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is an oncofetal protein that is physiologically expressed during embryogenesis, largely disappears by birth, but can be reexpressed pathologically in transformed tissues of many hematological and solid cancers. VLS-101 is an antibody-drug conjugate (ADC) comprising a rapidly internalizing, humanized monoclonal antibody (UC-961) that recognizes extracellular ROR1, a cleavable linker, and the anti-microtubule cytotoxin, monomethyl auristatin E (MMAE). Methods: This first-in-human, Phase 1 study evaluated the safety, pharmacokinetics (PK), pharmacodynamics (PD), immunogenicity, and efficacy of VLS-101 in patients unselected for tumor ROR1 expression who had previously treated chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), mantle cell lymphoma (MCL), marginal zone lymphoma (MZL), or Richter transformation lymphoma (RTL). VLS-101 was infused over 30 min every 3 wk until cancer progression or intolerable toxicity. After accrual of 1 patient at the first dose level, cohorts were enrolled by 3+3 dose escalation with additional patients accrued and intrapatient dose escalation permitted to refine estimates of maximum tolerated dose and recommended dosing regimen (RDR). Results: 32 patients were enrolled, including 19 males and 13 females with median (range) ages of 70 (54-84) ys; ECOG performance status (n) of 0 (18), 1 (10), or 2 (4); and tumor types (n) of MCL (15), CLL (7), DLBCL (5), FL (3), MZL (1), and RTL (1). Patients had received a median (range) of 4 (1-24) prior systemic therapies including hematopoietic stem cell transplantation (5) and/or chimeric antigen receptor (CAR)-T or -natural killer (NK) cells (6). Among patients with MCL, 15/15 (100%) had received a Bruton tyrosine kinase inhibitor (BTKi), 13/15 (87%) discontinued the BTKi due to progressive disease, and 2/15 (13%) discontinued for atrial fibrillation after 15.6 or 68.5 months of BTKi therapy. Patients (n) by VLS-101 starting dose were 0.5 (1), 1.0 (3), 1.5 (3), 2.25 (11), and 2.5 (14) mg/kg. With intrapatient dose escalation, many patients (n) received a maximum of 2.25 mg/kg (12) or 2.5 mg/kg (17) during VLS-101 therapy (range: 1 to 13 cycles). Cycle 1 DLTs (n/N) by mg/kg dose level were 0.5 (0/1), 1.0 (0/3), 1.5 (0/3), 2.25 (1/11 [9%] Gr 4 neutropenia), and 2.5 (2/14 [14%]; one Gr 4 neutropenia; one Gr 3 diarrhea of uncertain cause). Gr 4 neutropenia occurred in 9/32 (28%) patients; 1/32 (3%) had neutropenic fever. Granulocyte colony-stimulating factor successfully ameliorated neutropenia. Baseline Gr 1 neuropathy was present in 10/32 (31%) patients. On-study reversible Gr 3 neuropathy occurred in 3/32 (9%) patients; no Gr 4 neuropathy occurred. Except for Gr ≤2 alopecia in 3/32 (9%) patients, other adverse events were not obviously drug-related. Considering all 175 infusions administered, drug-related infusion reactions, vomiting, tumor lysis syndrome, rash, hepatic or renal abnormalities, or QT prolongation were not observed. PK showed changes in ADC and MMAE exposures proportional with VLS-101 dose and a mean ADC half-life of ~2.5 d. PD indicated exposure-dependent ROR1 occupancy on circulating CLL cells. No neutralizing anti-drug antibodies were detected. Objective tumor responses were not seen in patients with other tumor types but were observed in 7/15 (47%) of patients with MCL (4 partial; 3 complete) and in 4/5 (80%) of patients with DLBCL (2 partial; 2 complete). From start of therapy, 6/7 patients with responding MCL have responses ongoing at 35, 38, 45, 47, 50, and 58 wk and 2/4 patients with responding DLBCL have responses ongoing at 23 and 47 wk of follow-up. Conclusions: In heavily pretreated patients, VLS-101 infusions were well tolerated and demonstrated a predictable safety profile consistent with an MMAE-containing ADC. Tumor selectivity was confirmed, with no evidence of ROR1-mediated toxicities or non-MMAE toxicities that would suggest normal tissue binding. Considering all data, the VLS-101 RDR was 2.5 mg/kg every 3 wk. Efficacy results provide clinical proof of concept for targeting ROR1 with VLS-101 and demonstrate durable objective responses in patients with advanced MCL or DLBCL, including those with prior BTKi or cellular therapies. Phase 1-2 studies of VLS-101 monotherapy and combination therapy in patients with hematological cancers and solid tumors are planned. Figure Disclosures Wang: Nobel Insights: Consultancy; Lu Daopei Medical Group: Honoraria; Oncternal: Consultancy, Research Funding; MoreHealth: Consultancy; Juno: Consultancy, Research Funding; Loxo Oncology: Consultancy, Research Funding; Acerta Pharma: Research Funding; InnoCare: Consultancy; OncLive: Honoraria; Guidepoint Global: Consultancy; VelosBio: Research Funding; Pulse Biosciences: Consultancy; Kite Pharma: Consultancy, Other: Travel, accommodation, expenses, Research Funding; Beijing Medical Award Foundation: Honoraria; Pharmacyclics: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; OMI: Honoraria, Other: Travel, accommodation, expenses; Celgene: Consultancy, Other: Travel, accommodation, expenses, Research Funding; BioInvent: Research Funding; Molecular Templates: Research Funding; Verastem: Research Funding; Dava Oncology: Honoraria; AstraZeneca: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Janssen: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Targeted Oncology: Honoraria. Barrientos:Gilead: Consultancy; Genentech: Consultancy; Bayer: Consultancy; Oncternal Therapeutics: Research Funding; Sandoz: Consultancy; Janssen: Honoraria; AstraZeneca: Consultancy. Furman:Verastem: Consultancy; Incyte: Consultancy; Janssen: Consultancy, Speakers Bureau; Loxo Oncology: Consultancy; Oncotarget: Consultancy; Pharmacyclics: Consultancy; Sunesis: Consultancy; TG Therapeutics: Consultancy, Research Funding; Acerta: Consultancy; Abbvie: Consultancy; AstraZeneca: Consultancy, Research Funding; Beigene: Consultancy; Genentech: Consultancy. Mei:Sanofi: Consultancy; Morphosys: Membership on an entity's Board of Directors or advisory committees. Barr:AstraZeneca: Consultancy, Research Funding; Verastem: Consultancy; Abbvie/Pharmacyclics: Consultancy, Research Funding; Merck: Consultancy; Morphosys: Consultancy; Gilead: Consultancy; Seattle Genetics: Consultancy; TG therapeutics: Consultancy, Research Funding; Celgene: Consultancy; Janssen: Consultancy; Genentech: Consultancy. Choi:Genentech: Consultancy; Pharmacyclics/Abbvie: Research Funding. de Vos:Bayer: Consultancy; Verastem: Consultancy. Patel:Celgene/BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; BeiGene: Consultancy; Kite: Consultancy; Janssen: Consultancy, Speakers Bureau; Genentech: Consultancy, Speakers Bureau; Adaptive Biotechnologies: Consultancy; Pharmacyclics: Consultancy, Speakers Bureau; AstraZeneca: Consultancy, Research Funding, Speakers Bureau. Rule:Janssen: Consultancy; Kite: Consultancy; Pharmacyclics: Consultancy. Flanders:VelosBio: Current Employment, Current equity holder in private company. Jessen:VelosBio: Current Employment, Current equity holder in private company; eFFECTOR: Current equity holder in private company. Riebling:VelosBio: Current Employment, Current equity holder in private company. Graham:Ce3: Current Employment. King:Ce3: Current Employment; VelosBio: Consultancy; AI Therapeutics: Consultancy. Schmidt:VelosBio: Current Employment, Current equity holder in private company; Gilead Sciences: Current equity holder in publicly-traded company. Lannutti:VelosBio: Current Employment, Current equity holder in private company; Gilead Sciences: Current equity holder in publicly-traded company. Johnson:Zentalis: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Current equity holder in publicly-traded company; Neoleukin: Current equity holder in publicly-traded company; Oncternal: Divested equity in a private or publicly-traded company in the past 24 months; Appelis: Divested equity in a private or publicly-traded company in the past 24 months; Acerta: Patents & Royalties; VelosBio: Current Employment, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Miller:Cleveland BioLabs: Consultancy, Current equity holder in publicly-traded company; Gilead Sciences: Current equity holder in publicly-traded company; Cancer Genetics: Current equity holder in publicly-traded company; Incuron: Consultancy; Zentalis: Consultancy, Current equity holder in publicly-traded company; AbbVie: Current equity holder in publicly-traded company; EpiThany: Current equity holder in private company; AstraZeneca: Current equity holder in publicly-traded company; VelosBio: Consultancy, Current Employment, Current equity holder in private company; AI Therapeutics: Consultancy, Current equity holder in private company; Catalys Pacific: Consultancy. Spurgeon:Cardinal Health: Honoraria; VelosBio: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Pharmacyclics: Consultancy; Bristol-Myers Squibb: Research Funding; Genentech: Research Funding; Gilead: Research Funding; Acerta: Research Funding; AstraZeneca: Research Funding; Genmab: Research Funding; Beigene: Research Funding; Verastem: Research Funding.

Background: Acalabrutinib (acala) is a next-generation, highly selective, covalent Bruton tyrosine kinase (BTK) inhibitor approved for patients (pts) with mantle cell lymphoma (MCL) who have received ≥1 prior therapy. The efficacy and safety of acala in relapsed/refractory (R/R) MCL pts was demonstrated in a single-arm phase 2 study (ACE-LY-004; NCT02213926) after a median follow-up of 26 mo (Wang M, et al. Leukemia. 2019;33:2762-6). Here, we present results after an additional year of follow-up. Methods: Adults with MCL and ECOG PS ≤2 who had relapsed or were refractory to 1-5 prior therapies, had no prior BTK/BCL-2 inhibitor exposure, and did not require warfarin/vitamin K antagonists, received oral acala 100 mg twice daily until progressive disease (PD) or toxicity. Overall response rate (ORR; investigator-assessed partial response [PR] or better per Lugano classification), duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety were assessed. Minimal residual disease (MRD) was analyzed in formalin-fixed, paraffin-embedded samples and peripheral blood by next-generation sequencing (5x10-6) in pts with available paired samples. Results: 124 pts were included (median age, 68 [range: 42-90] y; ECOG PS ≤1, 93%; bulky lymph nodes ≥10 cm, 8%; extranodal involvement, 72%; intermediate-/high-risk simplified MCL International Prognostic Index score, 44%/17%; median number of prior therapies, 2 [range: 1-5]; refractory disease, 24%). After a median follow-up of 38.1 mo (range: 0.3-59.5), 24 (19%) pts remain on treatment and an additional 31 pts (55 total; 44%) remain in follow-up for survival. Of the 31 pts in post-acala follow-up, 6 remain PD-free (4 received post-acala treatment: anticancer treatment combinations and allogeneic stem cell transplant [n=3]; radiotherapy [n=1]). ORR was 81% (95% CI: 74, 88); 48% (95% CI: 39, 57) achieved complete response (CR). Median DOR was 28.6 mo (95% CI: 17.5, 39.1) and the estimated 36-mo DOR rate was 41.9% (95% CI: 31.7, 51.8). Median PFS was 22.0 mo (95% CI: 16.6, 33.3; Figure); estimated 36-mo PFS rate was 37.2% (95% CI: 28.2, 46.1). ORR and PFS were not significantly different between subgroups divided by Ki-67 index (≤50%, >50%); PFS also did not differ significantly by prior treatment regimen (bendamustine/rituximab [BR]-based, non-BR) or prior therapy line (1, 2, ≥3). Median OS was not reached; estimated 36-mo OS rate was 60.5% (95% CI: 51.1, 68.7). Of 30 MRD-evaluable pts, 6 (20%) achieved CR and undetectable MRD (uMRD) and maintained uMRD at last assessment. The adverse event (AE) profile was largely unchanged with an additional year of follow-up. The most frequent AEs (≥20%) of headache (39%), diarrhea (37%), fatigue (30%), cough (23%), myalgia (22%), and nausea (22%) were primarily grade 1/2. Grade 3/4 AEs (≥5%) were neutropenia (11%), anemia (10%), and pneumonia (6%). Overall, 16 pts (13%) had cardiac AEs (11 with prior cardiac risk factors); 3 of the 16 pts had cardiac AEs in the last year of follow-up (grade 3/4: n=2). Overall, 6 pts (5%) had grade 3/4 cardiac AEs (acute coronary syndrome, acute myocardial infarction, complete atrioventricular block, cardiac failure, cardiorespiratory arrest, coronary artery disease, sinus arrest; n=1 each). One pt had grade 3/4 hypertension in the last year (total any grade, n=5 [4%]; total grade 3/4, n=2 [2%]). Five pts had bleeding AEs in the last year (n=46 [37%] total) including 2 with grade 3/4 AEs of gastrointestinal hemorrhage (n=2 total) and 1 with grade 3/4 subdural hematoma (n=1 total). Three pts had grade 3/4 infections in the last year (n=21 [17%] total). Treatment discontinuation was primarily due to PD (n=74; 60%) and AEs (n=14; 11%). Seventeen AEs led to discontinuation in 14 pts; each AE occurred in only 1 pt. There were 57 deaths (46%), most commonly due to PD (n=38; 31%) or AEs (n=6; 5%); 14 deaths (11%) occurred in the last year of follow-up (PD, n=9; other, n=1; unknown, n=4). There were 6 deaths due to AEs (bilateral pulmonary embolism, critical aortic stenosis, myelodysplastic syndrome, pneumonia, suicide, non-small cell lung cancer); none were related to acala. Conclusion: Extended follow-up demonstrates no emerging safety concerns for acala in R/R MCL pts. After a median of 38.1 mo, 19% of pts remain on acala. Overall, an estimated one-third of pts remain progression free at 36 mo, with median OS not yet reached. These data support long-term use of acala in R/R MCL pts. Disclosures Wang: Dava Oncology: Honoraria; Verastem: Research Funding; Loxo Oncology: Consultancy, Research Funding; Pulse Biosciences: Consultancy; OncLive: Honoraria; Molecular Templates: Research Funding; AstraZeneca: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Beijing Medical Award Foundation: Honoraria; BioInvent: Research Funding; Acerta Pharma: Research Funding; VelosBio: Research Funding; Targeted Oncology: Honoraria; Lu Daopei Medical Group: Honoraria; OMI: Honoraria, Other: Travel, accommodation, expenses; MoreHealth: Consultancy; Juno: Consultancy, Research Funding; Pharmacyclics: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Guidepoint Global: Consultancy; Nobel Insights: Consultancy; Janssen: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Kite Pharma: Consultancy, Other: Travel, accommodation, expenses, Research Funding; Celgene: Consultancy, Other: Travel, accommodation, expenses, Research Funding; InnoCare: Consultancy; Oncternal: Consultancy, Research Funding. Rule:Celgene: Consultancy; Celltrion: Consultancy; Roche Pharma AG: Consultancy, Research Funding; Janssen Oncology: Consultancy, Research Funding, Speakers Bureau; AstraZeneca: Consultancy. Zinzani:ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; TG Therapeutics, Inc.: Honoraria, Speakers Bureau; Kirin Kyowa: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen-Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Portola: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celltrion: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Verastem: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sandoz: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Servier: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Eusapharma: Consultancy, Speakers Bureau; EUSA Pharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Immune Design: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Immune Design: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kyowa Kirin: Consultancy, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau. Goy:Kite, a Gilead Company: Consultancy, Current equity holder in publicly-traded company, Honoraria, Other: leadership role, Research Funding; MD Anderson: Research Funding; Celgene: Honoraria, Research Funding; CALBG: Research Funding; Janssen: Consultancy, Honoraria, Other: leadership role, Research Funding; Hackensack UMC and University of Nebraska: Research Funding; Karyopharm: Research Funding; Xcenda: Consultancy; Regional Cancer Care Associates/OMI: Current Employment; COTA: Consultancy, Current equity holder in publicly-traded company, Other: leadership role; Acerta: Consultancy, Honoraria, Other: leadership role, Research Funding; RCCA/OMI: Current Employment; PracticeUpdate Oncology: Consultancy; Infinity Verastem: Research Funding; AbbVie: Research Funding; Morphosys: Research Funding; Genentech/Roche: Research Funding; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: leadership role, Research Funding; Bayer: Research Funding; Infinity: Research Funding; Constellation: Research Funding. Casasnovas:Abbvie: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Gilead: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Roche: Consultancy, Honoraria, Other: travel, accomodations, expenses, Research Funding; MSD: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Smith:Ignyta: Research Funding; Genentech: Research Funding; Bayer: Research Funding; AstraZeneca: Research Funding; Merck: Research Funding; De Novo Biopharma: Research Funding; Bristol Meyers Squibb: Research Funding; Ayala: Research Funding; Pharmacyclics: Research Funding; Millenium/Takeda: Consultancy; Acerta Pharma BV: Research Funding; Incyte: Research Funding; Karyopharm: Consultancy; Seattle Genetics: Research Funding; AstraZeneca: Consultancy; Portola: Research Funding; Beigene: Consultancy. Doorduijn:Roche: Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Morschhauser:Celgene: Membership on an entity's Board of Directors or advisory committees; Servier: Consultancy; Epizyme: Membership on an entity's Board of Directors or advisory committees; Genentech, Inc.: Consultancy; Abbvie: Membership on an entity's Board of Directors or advisory committees; F. Hoffmann-La Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Honoraria; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Panizo:Bristol-Myers Squibb, Kyowa Kirin: Speakers Bureau; Clínica Universidad de Navarra: Current Employment; Janssen, Roche: Membership on an entity's Board of Directors or advisory committees. Shah:Kite/Gilead, Celgene/Juno/BMS, Novartis, Pfizer, Amgen, Spectrum/Acrotech, Precision Biosciences, Beigene, AstraZeneca, Pharmacyclics/Jansen, Adaptive: Honoraria; NCCN: Vice-Chair, Acute Lymphoblastic Leukemia Working Group: Membership on an entity's Board of Directors or advisory committees; Kite/Gilead, Jazz, Incyte: Research Funding; Moffitt Cancer Center: Current Employment; Kite/Gilead, Precision Biosciences, Novartis, AstraZeneca: Other: TRAVEL, ACCOMMODATIONS, EXPENSES. Davies:Celegene, Roche, Kite Pharma, Celegene: Honoraria; Roche: Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Roche, Celgene, Kite Pharma, Acerta, Karyopharma, Regeneron, Incyte: Consultancy; Roche, Acerta Pharma, AstraZeneca, Celgene, Gilead, ADC Therapeutics, Gilead: Research Funding. Dupuis:Henri Mondor University Hospital Creteil France: Current Employment. Jacobsen:Merck, Pharmacyclics, F. Hoffmann-LaRoche, Novartis: Research Funding; Takeda: Honoraria; Acerta, AstraZeneca, Merck: Consultancy. Kater:Roche: Research Funding; Celgene: Research Funding; Genentech: Research Funding; Abbvie: Research Funding; Janssen: Research Funding. Le Gouill:Roche Genentech, Janssen-Cilag and Abbvie, Celgene, Jazz pharmaceutical, Gilead-kite, Loxo, Daiichi-Sankyo and Servier: Honoraria; Loxo Oncology at Lilly: Consultancy. Oberic:Roche, Janssen: Consultancy; Roche: Honoraria; Roche, Janssen: Other: Travel, Accommodations, Expenses. Robak:Sandoz: Consultancy, Honoraria; Octapharma: Honoraria; AbbVie: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; UCB: Honoraria, Research Funding; Pharmacyclics LLC, an AbbVie Company: Honoraria, Research Funding; Acerta: Research Funding; Roche: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Medical University of Lodz: Current Employment; GSK: Research Funding; Novartis: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; UTX-TGR: Research Funding; Takeda: Consultancy; Morphosys: Research Funding; BioGene: Honoraria, Research Funding; Bristol Meyers Squibb: Research Funding; Pfizer: Research Funding; Momenta: Consultancy. Brock:Jazz Pharmaceuticals Inc: Current Employment; Acerta Pharmaceuticals: Ended employment in the past 24 months; Astra Zeneca: Current equity holder in publicly-traded company. Patel:AstraZeneca: Current Employment, Current equity holder in publicly-traded company. Tao:Clindata Insight inc: Ended employment in the past 24 months; Acerta Pharma, LLC: Current Employment.

Mantle cell lymphoma (MCL) is a rare and aggressive form of non-Hodgkin lymphoma. It is predominantly a disease of older individuals, with a median age at presentation of ∼70 years. For the majority of patients, the management revolves around immuno-chemotherapy often followed by maintenance rituximab, and at relapse, a range of options are available. For the younger patient, it is possible to be more intensive with therapy, consolidate responses with high-dose procedures, and in a few there might be the prospect of a cure. The incorporation of high-dose cytarabine into the treatment algorithm has had a major impact on outcomes, with approximately half of the patients alive at 10 years whether an autologous stem cell transplant is adopted or not. Allogeneic transplantation produces some very durable responses in the relapsed setting and has a potential role up front in the highest-risk patients. However, with the advent of Bruton tyrosine kinase inhibitor and other highly effective nontraditional chemotherapeutic approaches, there is the potential for the management of this disease to change fundamentally over the next few years.

To the editor: The inhibitor of Bruton’s tyrosine kinase (BTK) ibrutinib has transformed the treatment of chronic lymphocytic leukemia (CLL); many patients with previously untreatable disease may now enter durable remissions.[1][1],[2][2] Nevertheless, the kinome of ibrutinib is broad, resulting

Introduction: CD20-specific monoclonal antibodies (mAbs) have demonstrated efficacy in the treatment of B-cell non-Hodgkin lymphomas (B-NHL); however, a significant proportion of patients (pts) present with refractory disease or will experience relapse. GEN3013 (DuoBody®-CD3×CD20) is the first subcutaneously administered IgG1 bispecific antibody (bsAb) that targets the T-cell surface antigen CD3 and the B-cell surface antigen CD20, triggering T-cell-mediated killing of B cells. In vitro, GEN3013 efficiently activates and induces cytotoxic activity of CD4+ and CD8+ T cells in the presence of B cells (Hiemstra et al. Blood 2018), and results in long-lasting depletion of B cells in cynomolgus monkeys. Subcutaneous (SC) GEN3013 in cynomolgus monkeys resulted in lower plasma cytokine levels, and similar bioavailability and B-cell depletion, compared with intravenous administration. GEN3013 has higher potency in vitro than most other CD3×CD20 bsAbs in clinical development (Hiemstra et al. HemaSphere 2019). SC GEN3013 in pts with B-NHL is being evaluated in a first-in-human, Phase 1/2 trial (NCT03625037), which comprises a dose-escalation part and a dose-expansion part. Here we report preliminary dose-escalation data. Methods: Pts with CD20+ B-NHL with relapsed, progressive, or refractory disease following anti-CD20 mAb treatment, and ECOG PS 0-2 were included. During dose escalation, pts received SC GEN3013 flat dose in 28-day cycles (q1w: cycle 1-2; q2w: cycle 3-6; q4w thereafter) until disease progression or unacceptable toxicity. Risk of cytokine release syndrome (CRS) was mitigated with the use of a priming dose and premedication with corticosteroids, antihistamines, and antipyretics. Primary endpoints were adverse events (AEs) and dose-limiting toxicities (DLTs). Secondary endpoints included pharmacokinetics (PK), immunogenicity (anti-drug antibodies [ADA]), pharmacodynamics (PD) (cytokine measures; laboratory parameters), and anti-tumor activity (tumor size reduction; objective and best response). Results: At data cut-off (June 28, 2019), 18 pts were enrolled into the dose-escalation part of the trial, with safety data available for pts receiving doses starting at 4 µg. Most pts had diffuse large B-cell lymphoma (DLBCL; n=14) and were heavily pre-treated; 10 pts had received ≥3 prior lines of therapy (overall median [range]: 3 [1-11]). The median age was 58.5 years (range: 21-80), and 13 pts were male. At a median follow-up of 1.9 months, pts received a median of 5 doses (range: 1-14); treatment is ongoing in 6 pts. Twelve pts discontinued treatment due to progressive disease. Six pts died (2 during treatment, 4 during survival follow-up), all due to disease progression and unrelated to treatment. The most common (n≥5) treatment-emergent AEs were pyrexia (n=8), local injection-site reactions (n=7), diarrhea (n=5), fatigue (n=5), and increased aspartate aminotransferase (n=5). The most common Grade (G) 3/4 AEs were anemia (n=3) and neutropenia (n=3). Despite increasing GEN3013 doses, all CRS events were non-severe (initial observation: 3/8 pts, G1: n=1, G2: n=2; following modification of premedication plan [corticosteroids for 3 days]: 6/10 pts, G1: n=4, G2: n=2). Increases in peripheral cytokine (IL6, IL8, IL10, IFNγ, TNFα) concentrations after GEN3013 dosing correlated with clinical symptoms of CRS in most pts. No pts had tumor lysis syndrome or neurological symptoms. No DLTs were observed. GEN3013 PK profiles reflect SC dosing; Cmax occurred 2-4 days after dosing. No ADAs were detected. PD effects following GEN3013 dosing were observed at dose levels as low as 40 µg and included rapid, complete depletion of circulating B cells (if present after prior anti-CD20 therapy) and peripheral T-cell activation and expansion. The first evidence of clinical activity was observed at a dose level of 120 µg, with complete metabolic response observed in a pt with DLBCL. Conclusions: Subcutaneously administered GEN3013, a potent CD3×CD20 bsAb, shows good tolerability and early evidence of clinical activity at low dose levels in heavily pretreated pts with relapsed or refractory B-NHL. All CRS events were non-severe and did not lead to discontinuation. No DLTs were observed. Dose escalation is ongoing; updated data will be presented. Dose expansion will begin upon determining the recommended Phase 2 dose (RP2D) (NCT03625037). Disclosures Lugtenburg: Janssen Cilag: Honoraria; Roche: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria; Servier: Consultancy, Honoraria, Research Funding; Genmab: Consultancy, Honoraria; BMS: Consultancy; Takeda: Consultancy, Honoraria, Research Funding. Mous:Bristol-Myers Squibb: Honoraria; Celgene: Honoraria; Sandoz: Honoraria; Roche: Honoraria; Abbvie: Honoraria; Takeda: Honoraria, Research Funding; Janssen Cilag: Consultancy, Honoraria; MSD: Honoraria; Gilead: Consultancy, Honoraria, Research Funding. Clausen:Abbvie: Other: Travel grant to attend ASH 2019. Johnson:Boehringer Ingelheim: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Honoraria; Epizyme: Honoraria, Research Funding; Incyte: Honoraria; Takeda: Honoraria; Genmab: Honoraria; Bristol-Myers Squibb: Honoraria; Kite: Honoraria; Novartis: Honoraria. Rule:Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Astra-Zeneca: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria; TG Therapeutics: Consultancy, Honoraria; Napp: Consultancy; Kite: Consultancy. Oliveri:Genmab: Employment, Equity Ownership. DeMarco:Genmab: Employment, Equity Ownership. Hiemstra:Genmab: Employment, Equity Ownership, Other: Warrants. Chen:Genmab: Employment. Azaryan:Genmab: Employment. Gupta:Genmab: Employment, Equity Ownership. Ahmadi:Genmab Inc: Employment, Other: stock and/or warrants. Hutchings:Incyte: Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Genmab: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; Janssen: Research Funding; Pfizer: Research Funding.

Introduction: Targeting immune cells in the tumor microenvironment is an attractive approach to improving antitumor activity of standard therapy in r/r hematologic malignancies. Durvalumab is a monoclonal antibody that blocks programmed cell death ligand-1 (PD-L1), allowing T cells to recognize and kill tumor cells. Methods: The FUSION NHL-001 study (NCT02733042) is a phase 1/2 study assessing safety and efficacy of durvalumab as monotherapy or in combination. Eligible patients (pts) must have had r/r DLBCL or FL after ≥1 systemic therapy requiring therapeutic intervention. Other inclusion criteria include ECOG performance status 0-2 and ≥1 CT-measurable lesion. Pretreatment tumor biopsies were collected to assess biomarkers of response to durvalumab combination therapies. Pts with r/r B-cell neoplasms were enrolled into 1 of 4 arms that included durvalumab monotherapy (Arm D) or in combination with lenalidomide ± rituximab (Arm A), ibrutinib (Arm B), or rituximab ± bendamustine (Arm C). Durvalumab was given at a fixed dose of 1500 mg every 4 weeks. The study consisted of 2 parts: dose finding (except for Arm D) to establish the recommended phase 2 dose (RP2D) for each combination and dose confirmation. We present final subset analyses for pts with DLBCL and FL treated in Arms A, C, and D. Results: A total of 38 DLBCL and 22 FL pts were enrolled. Baseline characteristics are presented in Tables 1 and 2. Arm A was prematurely closed after an FDA announcement regarding safety concerns with combination of lenalidomide and checkpoint inhibitors in multiple myeloma; therefore, RP2D for lenalidomide ± rituximab could not be defined. However, 4 pts (DLBCL, n=1; FL, n=3) experienced dose-limiting toxicities (DLTs): febrile neutropenia (lenalidomide 10 mg + rituximab), headache, hepatitis, and thrombocytopenia (lenalidomide 20 mg + rituximab). One pt with DLBCL experienced DLT in Arm C (neutropenia) when treated with bendamustine 90 mg/m2 + rituximab. RP2D for bendamustine was established as 70 mg/m2. Durvalumab treatment (13 infusions) was completed for 10 (DLBCL, n=4; FL, n=6) pts (17%), 2 in Arm A and 8 in Arm C; the main reason for durvalumab withdrawal was disease progression. During the study, 38 pts (63%) experienced 81 serious adverse events (SAEs), most frequently related to infections (Figure 1). A total of 22 immune-mediated AEs (imAEs) related to durvalumab were reported in 13 pts (grade 1, 2, and 3 in 9, 7, and 6 cases, respectively): transaminitis and increased bilirubin (9 events), diarrhea (5 events), rash and pruritus (5 events), thyroid disorder (2 events), and infusion-related reaction (1 event). Two pts were treated with systemic steroids, both for grade 3 transaminitis. Others received symptomatic treatment. Ten pts experienced AEs that led to any drug discontinuation: 4 in Arm A (cerebral ischemia, febrile neutropenia, myalgia, hyponatremia), 3 in Arm C (transaminitis; neutropenia in 2 pts) and 3 in Arm D (drug reaction with eosinophilia and systemic symptoms, gastrointestinal perforation, prolonged QT). There were 6 grade 5 AEs, none considered related to study drugs. For pts with DLBCL (Table 3), overall response rate (ORR) was 18% and complete response rate (CRR) was 8%. Median progression-free survival (PFS) (Figure 2) was 2.5 months (95% CI, 1.25-5.13). There were 30 deaths on study (2, 19, and 9 pts in Arms A, C, and D, respectively), 24 (80%) related to disease progression. Median overall survival (OS) was 7.9 months (2.66-15.31). For pts with FL (Table 3), ORR was 59% and CRR was 27%. Median PFS (Figure 3) was 10.6 months (4.63-NE). There were 6 deaths on study (2 and 4 pts in Arms A and D, respectively); 3 (50%) were related to disease progression and 1 to second primary malignancy (bladder cancer, Arm A). Median OS was not reached. An interferon-γ signature comprising 4 genes, IFN-γ, CD274, LAG3, and CXCL9, trended higher with best ORR in pts with r/r DLBCL (N=30, P=0.06) and FL (N=18, P=0.01) independent of treatment arm (Arms A, C, and D included in analysis). Conclusions: Durvalumab as monotherapy or in combination in DLBCL and FL is tolerable without unexpected safety signals but requires close monitoring. Durvalumab alone or in combination appeared to add limited benefit to therapy for r/r DLBCL or FL. However, use of an interferon-γ gene signature may serve as a biomarker by which to enrich for r/r NHL pts that may be more responsive to anti-PD-L1-based therapy and will require further investigation. Disclosures Casulo: Gilead: Honoraria, Other: Travel, accommodation, expenses; Roche: Other: Travel, accommodation, expenses; Celgene: Research Funding. Santoro:MSD: Speakers Bureau; Lilly: Speakers Bureau; Sandoz: Speakers Bureau; BMS: Consultancy; Takeda: Speakers Bureau; BMS: Speakers Bureau; Abb-Vie: Speakers Bureau; Amgen: Speakers Bureau; Celgene: Speakers Bureau; AstraZeneca: Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; Arqule: Consultancy, Speakers Bureau; Eisai: Consultancy, Speakers Bureau; Novartis: Speakers Bureau; Bayer: Consultancy, Speakers Bureau; Servier: Consultancy, Speakers Bureau; Roche: Speakers Bureau; Gilead: Consultancy, Speakers Bureau. Ando:Eisai: Research Funding. Le Gouill:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Roche-Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support. Ruan:Celgene: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Pharmacyclics LLC, an AbbVie company: Research Funding; Juno: Consultancy; Kite: Consultancy. Radford:Novartis: Consultancy, Honoraria; ADC Therapeutics: Consultancy, Research Funding; BMS: Consultancy, Honoraria; AstraZeneca: Equity Ownership, Research Funding; Seattle Genetics: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Research Funding; GSK: Equity Ownership. Arcaini:Celgene, Roche, Janssen-Cilag, Gilead: Other: Travel expenses; Gilead Sciences: Research Funding; Celgene: Speakers Bureau; Bayer, Celgene, Gilead Sciences, Roche, Sandoz, Janssen-Cilag, VERASTEM: Consultancy. Pinto:Roche: Speakers Bureau; Roche, Takeda: Other: Travel grants; EDO-Mundipharma: Patents & Royalties; Roche, MSD, Bristol-Myers Squibb, Servier: Honoraria; Servier, Roche, Bristol-Myers Squibb, MSD: Membership on an entity's Board of Directors or advisory committees. Izutsu:Eisai, Chugai, Zenyaku: Honoraria; Eisai, Symbio, Chugai, Zenyaku: Research Funding; Celgene: Consultancy; Chugai, Celgene, Daiichi Sankyo, Astra Zeneca, Eisai, Symbio, Ono, Bayer, Solasia, Zenyaku, Incyte, Novartis, Sanofi, HUYA Bioscience, MSD, Astellas Amgen, Abbvie, ARIAD, Takeda, Pfizer: Research Funding; Kyowa Kirin, Eisai, Takeda, MSD, Chugai, Nihon Medi-physics, Janssen, Ono, Abbvie, Dainihon Sumitomo, Bayer, Astra Zeneca, HUYA Japan, Novartis, Bristol-Byers Squibb, Mundi, Otsuka, Daiichi Sankyo, Astellas, Asahi Kasei: Honoraria. Rule:Astra-Zeneca: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; TG Therapeutics: Consultancy, Honoraria; Napp: Consultancy; Kite: Consultancy. Munoz:Pharmacyclics /Janssen: Consultancy, Research Funding, Speakers Bureau; Bayer: Consultancy, Speakers Bureau; Merck: Consultancy; Kyowa: Consultancy, Honoraria, Speakers Bureau; Seattle Genetics: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene/Juno: Consultancy, Research Funding; Genentech: Consultancy, Research Funding, Speakers Bureau; Kite/Gilead: Consultancy, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Consultancy; Alexion: Consultancy; Pfizer: Consultancy; Fosunkite: Speakers Bureau; AstraZeneca: Speakers Bureau; Portola: Research Funding; Incyte: Research Funding. Casadebaig:Celgene Corporation: Employment, Equity Ownership. Fox:Celgene Corporation: Employment, Equity Ownership. Rettby:Celgene Corporation: Employment, Equity Ownership. Dell'Aringa:Celgene Corporation: Employment, Equity Ownership. Delarue:Celgene Corporation: Employment, Equity Ownership. Newhall:Celgene Corporation: Employment, Equity Ownership. Czuczman:Celgene Corporation: Employment, Equity Ownership. Cartron:Roche, Celgene: Consultancy; Sanofi, Gilead, Janssen, Roche, Celgene: Honoraria. OffLabel Disclosure: Durvalumab is a PD-L1 blocking antibody indicated for the treatment of patients with 1) locally advanced or metastatic urothelial carcinoma who have disease progression during or following platinum-containing chemotherapy, or who have disease progression within 12 months of neoadjuvant or adjuvant treatment with platinum-containing chemotherapy, or 2) unresectable, stage 3 NSCLC whose disease has not progressed following concurrent platinum-based chemotherapy and radiation therapy.

Introduction In MCL, progression-free survival (PFS) generally declines with each successive line of chemoimmunotherapy (CIT). We have previously published that with ibrutinib, a first-in-class oral inhibitor of Bruton's tyrosine kinase and a standard of care treatment (tx) for R/R MCL, median PFS exceeded 2 years (yrs) when used at first relapse (Rule S, et al. Haematologica. 2018;104:e211-e214). Here we present an updated pooled analysis with 15 months (mos) of additional follow-up, and for the first time, a comparison of outcomes with ibrutinib versus the prior regimen. Methods Patients (pts) enrolled in SPARK (MCL2001; NCT01599949), RAY (MCL3001; NCT01646021), and PCYC-1104 (NCT01236391) received ibrutinib 560 mg orally once daily until progressive disease or unacceptable toxicity, and pts benefiting at end of study could enroll in the open-label long-term extension study CAN3001 (NCT01804686). Tumor response (by Cheson B, et al; 2007 criteria) and PFS were investigator assessed. Positron emission tomography scans were not routine but confirmatory for complete responses (CRs). Disease evaluations in CAN3001 were per routine clinical practice and pts could continue tx as long as clinically benefiting. For the regimen prior to ibrutinib, time to next tx (TTNT: date of first dose of prior regimen to date of first dose of ibrutinib) was used as a surrogate for PFS. Progression of disease (POD) on frontline tx was categorized as early (TTNT < 24 mos) or late (TTNT ≥ 24 mos). Medians are reported with 95% confidence intervals (CIs). Results As of April 2019, the median (range) follow-up and exposure for 370 ibrutinib-treated pts (median 2 [range 1-9] prior lines of therapy [LOT]) were 41 (0.2-92.4) mos and 11.1 (0.03-92.4) mos, respectively, and 32/87 (37%) pts in CAN3001 remain on ibrutinib. Tx duration was ≥ 3 yrs in 22.4% of pts. At 5 yrs, PFS and overall survival (OS) rates (95% CI) were 19% (15-24) and 41% (35-47), respectively. Pts with 1 prior LOT and pts achieving CR had the best outcomes (Table). Median PFS and OS in pts with 1 prior LOT were 25.4 (17.5-51.8) and 61.6 (36.0-not estimable [NE]) mos, respectively (Figure A). Median PFS and OS in pts with CR were 67.7 (51.7-NE) mos and NR (NE-NE) mos, respectively. Overall, median PFS on ibrutinib was 12.5 (9.8-16.6) mos, while median TTNT on the prior regimen was 10.9 (9.1-12.6) mos (Figure B). PFS with ibrutinib was longer than TTNT on the prior regimen for 50% of pts and was ≥ 12 mos longer than TTNT on the prior regimen for 27% of pts. Factors ≥ 10% more common in pts achieving ≥ 12-mo longer PFS versus those who did not included low-risk simplified MCL International Prognostic Index (sMIPI), no extranodal disease, no bulky disease (≥ 5 cm), nonblastoid histology, TP53 wild type, and best response of CR. Ninety-nine pts received ibrutinib in second line (44% ≥ 70 yrs old, 26% with high-risk sMIPI, 1% with Eastern Cooperative Oncology Group performance status ≥ 2, 6% with blastoid variant). Forty-three of 99 pts (43%) had early frontline POD and 56 (57%) had late frontline POD. In pts with early frontline POD, median PFS with ibrutinib (13.8 [4.3-24.2] mos) was similar to median frontline TTNT (14.0 [12.0-16.1] mos); median duration of response (DOR) and OS on ibrutinib were 22.1 (10.6-35.6) and 23.5 (10.3-61.6) mos, respectively. In pts with late frontline POD, median PFS with ibrutinib (57.5 [31.1-NE] mos) was longer than median frontline TTNT (42.2 [35.2-46.5] mos); median DOR and OS on ibrutinib were NE (33.1-NE) and NE (51.9-NE), respectively. There was no late unexpected toxicity. Conclusions This pooled analysis of ibrutinib in R/R MCL with extended follow-up up to 7.5 yrs indicates a late plateau in the PFS curve with a significant number of pts experiencing remission > 5 yrs. Tx with ibrutinib in second versus later lines extended median PFS and increased likelihood of a CR. Pts achieving CRs with ibrutinib had durable responses, with a median duration > 5.5 yrs. Contrary to historical outcomes with CIT, half of all pts treated with ibrutinib experienced a longer PFS than with the prior regimen, and one quarter had ≥ 1 additional yr of benefit. In pts with early frontline POD, ibrutinib delivered a similar magnitude of PFS benefit in second line. In chemosensitive pts with late frontline POD, second-line ibrutinib PFS was 36% longer than frontline outcome. There was no notable emerging toxicity with additional follow-up. Disclosures Rule: Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Astra-Zeneca: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria; TG Therapeutics: Consultancy, Honoraria; Napp: Consultancy; Kite: Consultancy. Dreyling:Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: scientific advisory board, Research Funding, Speakers Bureau; Janssen: Consultancy, Other: scientific advisory board, Research Funding, Speakers Bureau; Novartis: Other: scientific advisory board; Celgene: Consultancy, Other: scientific advisory board, Research Funding, Speakers Bureau; Bayer: Consultancy, Other: scientific advisory board, Speakers Bureau; Mundipharma: Consultancy, Research Funding; Acerta: Other: scientific advisory board; Gilead: Consultancy, Other: scientific advisory board, Speakers Bureau; Sandoz: Other: scientific advisory board. Goy:Pharmacyclics/Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Grants outside of the submitted work, Research Funding; COTA: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Other: leadership role for profit healthcare company; Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Grants outside of the submitted work; Takeda: Other: Grants outside of the submitted work; Genentech: Other: Grants outside of the submitted work, Research Funding; University of Nebraska: Research Funding; Hakensackumc: Research Funding; Astrazenca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Hackensack University Medical Center, RCCA: Employment; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Acerta: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Grants outside of the submitted work, Research Funding. Hess:Celgene: Consultancy, Employment, Honoraria, Other: personal fees, Research Funding; Roche: Consultancy, Employment, Honoraria, Other: personal fees, Research Funding; CTI: Consultancy, Employment, Honoraria, Research Funding; Pfizer: Other: personal fees, Research Funding; Janssen: Consultancy, Honoraria, Other: personal fees; Novartis: Consultancy, Honoraria; MorphoSys: Consultancy, Honoraria. Auer:Hartley Taylor: Honoraria; Celgene: Other: personal fees; Janssen: Honoraria, Other: personal fees, Research Funding; Bristol-Myers Squibb: Other: personal fees. Kahl:Seattle Genetics: Consultancy; BeiGene: Consultancy; TG Therapeutics: Consultancy; ADC Therapeutics: Consultancy, Research Funding. Qi:Janssen: Employment. Deshpande:Janssen: Employment. Parisi:Janssen: Employment. Wang:Juno Therapeutics: Research Funding; VelosBio: Research Funding; Celgene: Honoraria, Research Funding; Aviara: Research Funding; Loxo Oncology: Research Funding; Dava Oncology: Honoraria; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Pharmacyclics: Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; MoreHealth: Consultancy, Equity Ownership; Acerta Pharma: Consultancy, Research Funding; Kite Pharma: Consultancy, Research Funding; Guidepoint Global: Consultancy; BioInvent: Consultancy, Research Funding.

Background: Although diffuse large B cell lymphoma (DLBCL) can be cured using immuno-chemotherapy, 40% of patients experience relapse or refractory disease. Large-scale profiling studies have mainly focused on DLBCL at diagnosis, resolving different outcome groups based on gene expression (e.g. cell-of-origin (COO) or molecular high grade), MYC/BCL2 translocations (double-hit lymphoma) or gene mutations and copy number aberrations (Schmitz et al, NEJM 2018; Chapuy et al, NatureMedicine 2018). In comparison, longitudinal studies have been hindered by the limited availability of sequential biopsy samples. To date, the relapse-specific gene mutations identified are limited and inconsistent across studies. In our study, we have focussed attention on the changes in gene expression profile (GEP) accompanying DLBCL relapse. Methods: We retrospectively collected archival paired diagnostic/relapse formalin fixed paraffin embedded tumor biopsies from 38 de novo DLBCL patients collected from multiple UK sites treated with rituximab-based immuno-chemotherapy, where partial or complete remission was reported following treatment. COO classification was performed by the Lymph2Cx assay on NanoString to distinguish activated B-cell-like (ABC) and germinal center B-cell-like (GCB) subtypes. The Ion AmpliSeq™ Transcriptome Human Gene Expression Kit was used to measure the expression levels of > 20,000 genes on the paired samples. Results: COO remained stable from diagnosis to relapse in 17 ABC-ABC pairs, 11 GCB-GCB pairs and 4 unclassified (UNC)-UNC pairs. Frank COO switching was observed in 6 cases (1 ABC-GCB, 2 ABC-UNC, 2 GCB-UNC, 1 UNC-ABC). Pairs with stable COO were taken forward for further analysis. Gene expression analysis using the limma R package identified 163 and 136 genes as differentially expressed (DE) (p 1) between the diagnostic and relapse biopsies in ABC and GCB tumors respectively, with only a one gene overlap. Gene Set Enrichment Analysis further suggested that ABC and GCB relapses are mediated via different mechanisms, with tumor growth and proliferation signatures enriched in ABC relapses, whilst adaptive immunity-related signatures accompanied GCB relapses. Next, we aimed to utilise our relapse-specific genes to identify outcome predictors at diagnosis using publicly available GEP datasets. In order to increase our discovery power and accuracy, a larger set of DE genes from the paired differential analysis (796 genes in ABC pairs and 387 from GCB pairs) were selected (p The prognostic significance of this 30-gene discriminator was successfully validated using a linear predictor in two independent GEP datasets: 1) a population-based cohort (Lenz et al, NEJM 2008) with 93 R-CHOP-treated ABC cases identifying 47 low and 46 high-risk cases (HR=1.92, p=0.046, C-index=0.77; Fig1.C) and 2) a clinical trial dataset (REMoDL-B, Davies et al, Lancet Oncol 2019) with 255 ABC cases identifying 110 low and 145 high-risk ABC cases (HR=1.95, p=0.0051, C-index=0.70; Fig1.D). Conclusions: Here we describe a 30-gene discriminator in ABC-DLBCL, derived from genes differentially expressed between diagnosis and relapse, that allowed the definition of clinically distinct high and low risk subgroups in ABC-DLBCLs at diagnosis. The clinical translation of such a tool may be useful to guide therapy for this unfavourable subgroup of ABC-DLBCLs. Validation of this signature is currently underway in additional datasets and further study is required to understand the contribution of these genes in DLBCL pathology. Disclosures Korfi: Roche: Consultancy. Burton:Celgene: Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees. Rule:TG Therapeutics: Consultancy, Honoraria; Napp: Consultancy; Kite: Consultancy; Pharmacyclics: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Astra-Zeneca: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Crosbie:Janssen: Honoraria. Scott:Celgene: Consultancy; Janssen: Consultancy, Research Funding; NanoString: Patents & Royalties: Named inventor on a patent licensed to NanoSting [Institution], Research Funding; Roche/Genentech: Research Funding. Rimsza:NanoSting: Patents & Royalties: Named inventor on a patent licensed to NanoSting [Institution]. Davies:Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Research Funding; Bayer: Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria, Research Funding; Karyopharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Research Funding; Acerta Pharma: Honoraria, Research Funding; ADCT Therapeutics: Honoraria, Research Funding; BioInvent: Research Funding; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; MorphoSys AG: Honoraria, Membership on an entity's Board of Directors or advisory committees. Gribben:Abbvie: Consultancy, Honoraria, Research Funding; Acerta/Astra Zeneca: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Okosun:Gilead Sciences: Honoraria, Research Funding. Johnson:Epizyme: Honoraria, Research Funding; Novartis: Honoraria; Kite: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria; Boehringer Ingelheim: Honoraria; Takeda: Honoraria; Genmab: Honoraria; Celgene: Honoraria; Incyte: Honoraria. Fitzgibbon:Epizyme: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Speakers Bureau.

Background Effective treatment for relapsed, refractory (R/R) mantle cell lymphoma (MCL) post Bruton's Tyrosine Kinase inhibitor (BTKi) therapy represents an unmet clinical need with studies consistently reporting dismal outcome. No treatment strategy demonstrates superiority and there is currently no consensus on management. R-BAC (Rituximab, Bendamustine and Cytarabine) has demonstrated excellent upfront response rates in phase 2 trials (overall response rate (ORR) 100%, 2-year progression free survival (PFS) 95%, Visco et al 2013), but with durable responses also reported with other combination therapies there is a rationale to reserve R-BAC for post-BTKi relapse. Aims There is currently no data available assessing efficacy of R-BAC in the post BTKi setting. We first adopted this treatment strategy within routine clinical practice in 2015 and in this study have collected and analysed clinical outcomes across 20 centers in the United Kingdom and Italy. Methods 35 R/R MCL patients (pts) with prior BTKi therapy started R-BAC between October 2015 and February 2019. Treatment consisted of rituximab (375 mg/m2 or 500 mg) D1, bendamustine 70 mg/m2 D1 and D2 and cytarabine 500 mg/m2 D1 to D3 in a 28 day cycle. 29 pts were treated in the UK and 6 in Italy. Analysis included one pt with previous alloHSCT. Response to therapy was measured using Lugano classification (Cheson et al, 2014), although assessment of CR with bone marrow biopsy was not always undertaken. Baseline data, including response to previous BTKi, was collected retrospectively by the treating physician. The primary outcome was PFS to R-BAC. Results Median age at time of R-BAC was 66.3 years (range 43 to 81) and 82.9% of pts were male. At initial diagnosis MIPI was 34.5% low risk, 17.2% intermediate risk and 48.3% high risk; histology was 20.6% blastoid. Pts received a median 2 prior lines of systemic therapy (range 1 to 6). Frontline therapy included high dose cytarabine containing regimen (61.7%) plus consolidation AutoSCT (40.0%), R-CHOP (26.4%), R-CVP (2.9%), FC (2.9%) and ibrutinib plus rituximab (5.9%). 7 patients received maintenance rituximab (28.6%). 45.7% of patients commenced second line therapy within 2 years of initial diagnosis. Prior BTKi therapy included: ibrutinib (n=30), acalabrutinib (n=2), tirabrutinib (n=2) and M7583 (n=1). ORR to prior BTKi was 67.6% (CR 35.3%) and median PFS was 9.2 months. All patients stopped BTKi therapy due to progressive disease (94.3%) or failure to respond (5.7%). All but 1 patient received R-BAC directly after relapse on BTKi. Patients received a median of 4 cycles of treatment (range 1 to 6). 9 pts received attenuated doses of chemotherapy at clinician's discretion from start of therapy and 13 additional pts received attenuated doses beyond cycle 1 (62.9% of all patients received some form of dose attenuation). ORR to R-BAC was 82.3% (CR/CRu rate 55.9%), median PFS 9.3 months (see fig. 1) and median OS 12.2 months. Importantly, outcome for 11 pts ≥70 yrs was similar to younger pts (median PFS 10.6 months vs 8.6 months, p=0.83). 53.5% of evaluable patients demonstrated longer duration of response compared with preceding BTKi. 25 pts completed the planned treatment course, 2 stopped early due to excess toxicity (prolonged cytopenias and infection) and 8 stopped early due to progressive disease. 9 pts received subsequent consolidation alloSCT, and 1 DLI. Although follow-up is short only 1 patient to receive alloSCT has relapsed. 13 patients overall remain in remission, including 5 beyond 12 months. 18 patients (51.4%) required admission during R-BAC, including 15 with neutropenic fever (42.8%) and 72.7% patients required transfusion support. There were no treatment related mortalities. Conclusion This high risk population with a short PFS to prior BTKi demonstrated an excellent response rate to R-BAC. Favorable outcomes in the cohort consolidated with alloSCT, and the generally short duration of response in other pts, suggests R-BAC can be primarily used as a bridge to alloSCT in suitable pts. Treatment had notable hematological toxicity but with efficacy maintained in older pts R-BAC remains a valid option in those deemed unsuitable for transplant, although judicious dose attenuation is advised. In an area lacking a clear therapeutic path, the results from our study support R-BAC being considered a new standard of care option for R/R MCL in the post BTK inhibitor setting. Disclosures Frewin: AbbVie: Other: Meeting attendance sponsorship ; Novartis: Consultancy, Other: Meeting attendance sponsorship . Eyre:Roche: Honoraria; Abbvie: Honoraria; Gilead: Consultancy, Honoraria, Other: commercial research support; Janssen: Honoraria. Lambert:Takeda Pharmaceuticals: Other: Funding to attend a scientific conference in 2018. Crosbie:Janssen: Honoraria. Rule:Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Astra-Zeneca: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Kite: Consultancy; Pharmacyclics: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria; TG Therapeutics: Consultancy, Honoraria; Napp: Consultancy.

Background. Novel targeted therapies have demonstrated high efficacy in relapse and/or refractory (R/R) MCL. Ibrutinib, a first in class BTK inhibitor, is approved for R/R MCL. Venetoclax, a first in class bcl-2 inhibitor, is currently under investigation in prospective trials in R/R MCL. Obinutuzumab is a type II glycol-engineered, humanized anti-CD20 antibody approved in frontline and R/R follicular lymphoma which has shown efficacy in MCL (Chiron Blood 2016, Le Gouill ICML/EHA 2019). Pre-clinical investigations have demonstrated the utility of combining these three molecules in MCL (Chiron et al, Blood 2016) The OAsIs trial (NCT02558816) is a multicenter, non-randomised, phase I study that was designed to assess the safety, tolerability and efficacy of Ibrutinib/ Venetoclax/Obinutuzumab in both R/R MCL and in newly diagnosed MCL. The study is divided into three steps (A, B,C, respectively) : step A enrolled nine R/R MCL who were treated with Ibrutinib plus Obinutuzumab and step B enrolled 24 R/R MCL patients who were treated with Ibrutinib/Venetoclax/Obinutuzumab (Venetoclax dose from 200 to 800mg ). The Ibrutinib/Venetoclax/Obinutuzumab combination demonstrated a good safety profile and high response rates in R/R MCL (step B). No DLT was reported in either step (Le Gouill et al, ASH 2018). Herein, we present the safety (primary objective), clinical and MRD results for Oasis step C where Ibrutinib/Venetoclax/Obinutuzumab was given to newly-diagnosed, untreated MCL patients. Methods: Obinutuzumab was given at 1000mg IV C1D1, 8, 15, C2-6 D1 and every 2 months until C23. Ibrutinib was given as a standard dose (560mg/d) from C1D2 and until progression. The dose of Venetoclax was 400mg (according to step B analysis and DSMC recommendations) and administered from C1-bis (to prevent TLS: C1-bis W1-20mg, C1-bis W2-50, C1-bis W3-100, C1-bis W4-200) and at 400mg from C2 to C23. Response was assessed by cheson 99 criteria at C2, C4 and C6 and by Lugano criteria at Cycle 6. MRD by ASO-qPCR (assay sensitivity 10-5) was measured at the end of C3 and 6 in blood and / or bone marrow. DLTs were assessed during the first 3 months (C1, C1-bis and C2) of treatment. Results. Fifteen untreated MCL patients were enrolled from August 2018 to April 2019, in 6 participating centers (France and UK). Median age at inclusion was 65y (range 51-77). All patients presented with stage III/IV disease and nodal disease (four patients had tumor mass >5cm). The MIPI score was high in 9 cases, intermediate in 5 and low in one case. One patient presented with pleomorphic variant. TP53 status at diagnosis was assessed in 13 patients (one was not informative and two are ongoing) of these one presented TP53 mutation. IGHV status (assessed in 13 patients, ongoing in 2) was mutated in two cases including the p53mutcase and not mutated in 8 (not informative in 3 cases). During the first three months of treatment (C1, C1-bis and C2), the relative dose intensity (ratio of delivered to the planned dose intensity) was 87% for Ibrutinib, 93% for Obinutuzumab and 100% for Venetoclax. During this period, non-hematological grade 3-4 AEs were hepatobiliary disorders (n=4; 3 patients with raised GGT-grade 3-, alanine -grade 3- and aspartate -grade 4- aminotransferase and one with biological cytolysis - grade 4) and rash (n=1; grade 3). Hematological grade 3-4 AEs were lymphocytosis (n=1; grade 3) and neutropenia (n=1; grade 4). All (n=15) patients are in response (including CR/uCR in 7 cases) at end of cycle 2 according to Cheson 99 criteria. In terms of MRD status, 8 patients (others are ongoing) were assessed at end of cycle 3 and all were MRD negative in BM (n=6) and/or in blood (n=8), including the p53mutpatient. Seven patients completed 6 cycles, all reached CR according to Lugano criteria (6 in CR/Cru according to Cheson criteria) and were MRD neg (in blood in all cases and in BM in 6 cases -one not done), including the P53mut patient. At date of last monitoring (Jul 2019), no disease progression is reported and all patients remain under the planned treatment. Conclusion. Ibrutinib/Venetoclax/Obinutuzumab combination therapy has a very good safety profile and shows high efficacity rates at the molecular level in untreated patients. Oasis step C is the first trial that report the use of Ibrutinib/Venetoclax/Obinutuzumab as frontline therapy in MCL. Disclosures Le Gouill: Janssen-cilag: Consultancy, Honoraria; Novartis: Consultancy; Abbvie: Consultancy, Honoraria; Roche Genentech: Consultancy, Honoraria; Gilead-Kite: Consultancy, Honoraria; Servier: Consultancy; loxo: Consultancy, Honoraria; Takeda: Consultancy. Morschhauser:Bayer: Membership on an entity's Board of Directors or advisory committees; Epizyme: Membership on an entity's Board of Directors or advisory committees; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; BMS: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees. Bouabdallah:Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Cartron:Roche, Celgene: Consultancy; Sanofi, Gilead, Janssen, Roche, Celgene: Honoraria. Chevallier:Jazz Pharmaceuticals: Honoraria; Daiichi Sankyo: Honoraria; Incyte: Consultancy, Honoraria. Rule:Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Astra-Zeneca: Consultancy, Honoraria; Napp: Consultancy; TG Therapeutics: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Kite: Consultancy. OffLabel Disclosure: Venetoclax, obinutuzumab in mantle cell lymphoma

Background: Although typically an aggressive disease some patients with Mantle Cell Lymphoma (MCL) follow an indolent course and may not benefit from immediate therapy. Several studies evaluating watch-and-wait (W&W) strategies in MCL show no detriment to patient survival and international guidelines acknowledge the strategy's suitability for a minority of patients. Differences in pathogenetic mechanisms have provided insight into variable clinical behaviour, but there is little clinical evidence to inform patient suitability for W&W. The MCL Biobank Observational Study is a prospective study designed to distinguish indolent from aggressive forms of MCL. Tissue samples and baseline characteristics are collected at enrolment. The study has recruited over 550 patients across the UK and remains open to recruitment. Method: This analysis includes 315 patients from 58 centers in the United Kingdom enrolled between January 2015 and March 2018. All new MCL diagnoses compatible with WHO diagnostic criteria were eligible. Patients were enrolled within 90 days of diagnosis and prior to receiving therapy. Baseline data was recorded including investigator decision to start systemic therapy or enter W&W. Clinical updates were provided at 6 month intervals and patients were followed-up for a minimum of 12 months. Standard statistical methods were used to examine which factors were associated with initial disease management and those remaining on W&W long-term. Time to treatment was measured from date of diagnosis until date of first treatment, patients who had not commenced treatment were censored at the last date of follow-up. Results: Median age of all patients was 71 (range 32-92), 68.9% were male, 53.5% were MIPI high risk and median follow up 26 months. At baseline 67.3% of patients received upfront systemic therapy, 4.1% received localized radiotherapy, 1.0% were palliated and 27.6% were on W&W 90 days beyond diagnosis. Estimated 2-year OS of the whole population was 77.5%. Patients on initial W&W tended to be older than those treated early (median 73 yrs vs. 71 yrs), had similar performance score (ECOG>1 OR 1.16, p=0.68) and no significant difference in WBC (WBC>15 OR 0.55, p=0.07). Although high risk MIPI was equally prevalent between the groups (OR 1.3, p=0.31) it was notable that no patient under 75 years was high risk in the observation group. Presence of measurable disease on CT discriminated between the two groups (OR 0.23, p= Of 87 patients followed on W&W 73.5% remained on observation at 1 year and 50.6% at 2 years, with median follow up 2.4 years. Univariate analysis revealed few baseline characteristics to be predictive for prolonged period of observation, in part relating to the low patient numbers, but key observations are displayed in figure 1. Patients with Ki67≥30% were less likely to remain on observation (HR 2.39, p=0.03), as were patients over 80 years old (HR 3.67, p=0.007), and those MIPI high risk compared to low risk (3.56, p=0.02). Conclusion: This study demonstrates the high prevalence of W&W in UK clinical practice and it provides reassurance to clinicians that half remain on observation beyond 2 yrs. LDH level and Ki67 status reflect the biological nature of disease and it is therefore not unexpected that lower levels predict for a more indolent course. However, with Ki67≥30 in 25% of patients observed beyond 2 years these measures alone are not sufficient to decide treatment. The tendency for older patients to be observed likely reflects a less aggressive clinical approach in patients with co-morbidities, and not the underlying biology. This explains the tendency for shortened observation period in older patients. The high prevalence of female patients in W&W is a striking observation that alludes to pathophysiological differences between the sexes that warrants further investigation. Although the study highlights clinicians are increasingly at ease adopting W&W in MCL, it also demonstrates the need for better predictive markers of indolent disease. This study aims to achieve this with analysis of the collected tissue samples. Disclosures Crosbie: Janssen: Honoraria. Rule:Sunesis: Consultancy, Honoraria; TG Therapeutics: Consultancy, Honoraria; Napp: Consultancy; Kite: Consultancy; Gilead: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Astra-Zeneca: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding.

Background: Ibrutinib has transformed the clinical approach to relapsed mantle cell lymphoma (MCL) with those receiving ibrutinib at first relapse obtaining the greatest benefit encouraging use earlier in the treatment algorithm (Rule et al, 2019). However, the general applicability of clinical trial findings is not established and concerns regarding ibrutinib tolerability persist, especially in non-trial populations enriched for frailer patients with multiple co-morbidities. In the United Kingdom, ibrutinib is funded as standard of care at first relapse. This study has analysed the clinical effectiveness and tolerability of this approach in a non-clinical trial real world population. Method: 23 centres across the United Kingdom contributed data from consecutive patients treated with ibrutinib for MCL at first relapse. Patients received standard dose 560 mg OD, unless documented, and commenced treatment between August 2014 and April 2019. Response to therapy was defined as per Lugano classification (Cheson et al, 2014), although CR assessment by bone marrow biopsy was not always undertaken. Data was collected on baseline characteristics, including response to prior therapy, and MIPI at time of relapse. The study primary outcome was PFS. Predictors of progression were determined using univariate Cox regression. Results: 169 patients were included in the study. Median age at start of ibrutinib was 72 years (range 33 to 97) and 122 (72.2%) were male. At diagnosis 13.5% had blastoid histology; 59.3% Ki67 ≥30%; 32.0% received cytarabine based induction and 27.8% HSCT consolidation; 11.2% received low intensity frontline therapy (i.e. not fit for R-CHOP) due to frailty. Median PFS following frontline therapy was 21.4 months (95% CI 14.6 to 28.3) and 52.1% progressed within 2 years. At start of ibrutinib 52.2% were MIPI high risk; 23.9% were ECOG 2 or higher and 2.4% had CNS involvement. Overall response rate (ORR) to ibrutinib was 71.6% with 30.4% achieving CR/CRu. Estimated median PFS from start of ibrutinib was 16.5 months (95% CI 11.5 to 21.5) and estimated OS 23.9 months (95% CI 13.0 to 34.8), with median follow up 26 months. Median PFS for patients with early relapse to frontline therapy (progression of disease 1 were also negative predictors of PFS (see table 1 for univariate analysis). 10 patients (5.9%) received attenuated dose from start of therapy due to frailty and 20 patients (11.8%) underwent dose reductions while on therapy due to drug toxicity. Of 109 patients to discontinue ibrutinib 72 (66.1%) were due to progressive disease, 15 for consolidation alloHSCT (13.8%), 13 due to medical co-morbidities and unrelated death (11.9%), and 9 due to drug toxicity (8.3%), including 1 bleed. Only 5.3% of all patients stopped therapy due to drug toxicity. Patients ≥80 yrs were more likely to stop therapy early for reasons other than progressive disease or alloHSCT (OR 2.92, p=0.02), but frailer patients who received low intensity frontline therapy also showed a trend for more durable response with second-line ibrutinib (PFS 10.0 months versus 4.0 months, p=0.36) justifying use in this patient group. Conclusion: This study population is enriched for several recognised adverse prognostic markers, including older age and poor performance status, which is likely to explain differences in PFS relative to clinical trial data. Despite these features response rates were similar, and it is notable that 46.7% of evaluable pts achieved longer PFS with ibrutinib than preceding front-line therapy. It is reassuring that the proportion of patients stopping ibrutinib due to toxicity was similar to trial data and bleeding events that required alterations to therapy were rare (3 cases, 1.8%). Although ibrutinib represents a significant breakthrough with clear benefit to most patients the results also highlight that outcome for many remains poor. 40% of patients progressed within 1 year of starting ibrutinib and median OS post ibrutinib was only 3.6 months. 35.2% of patients died within 1 month of documented relapse suggesting many, predominantly older patients, were not fit for further therapy. Of the 53 pts surviving beyond 1 month median OS was 7.5 months and 21.9% lived beyond 1 year. Improved treatment strategies in the post-ibrutinib setting remains a priority. Disclosures Rule: Pharmacyclics: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria; TG Therapeutics: Consultancy, Honoraria; Napp: Consultancy; Roche: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Astra-Zeneca: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Kite: Consultancy. Eyre:Gilead: Consultancy, Honoraria, Other: commercial research support; Abbvie: Honoraria; Janssen: Honoraria; Roche: Honoraria. Furtado:Abbvie: Honoraria. Shah:ABBVIE: Consultancy. Campbell:Novartis: Consultancy, Other: Educational support; Takeda: Consultancy, Other: Educational support; Bristol Myers-Squibb: Other: Educational support; Roche: Other: Educational support; Celgene: Other: Educational support. McCarthy:Janssen: Honoraria, Other: Educational grant to attend meetings . Lambert:Takeda Pharmaceuticals: Other: Funding to attend a scientific conference in 2018. McKay:Epizyme: Consultancy, Honoraria. Osborne:Roche: Consultancy, Honoraria, Other: Travel, Speakers Bureau; Gilead: Consultancy; MSD: Consultancy; Takeda: Consultancy, Honoraria, Other: Travel, Speakers Bureau; Novartis: Other: Travel; Pfizer: Honoraria, Speakers Bureau; Servier: Consultancy. Bishton:Takeda: Other: Travel support, Research Funding; AbbVie: Research Funding; Celltrion: Membership on an entity's Board of Directors or advisory committees, Other: travel support; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Roche: Other: Travel support, Research Funding. Crosbie:Janssen: Honoraria.

Background: Mantle cell lymphoma (MCL) is associated with a poor prognosis relative to other indolent B-cell lymphomas where clinicians have traditionally been reluctant to adopt watch-and-wait (W+W) strategies. US registry data from 2004 to 2011 demonstrated 6% of new diagnoses were observed beyond 3 months from diagnosis (Cancer 2016; 122: 2356-63), although other studies have demonstrated higher rates of W+W with no detriment to patient survival. Currently no consensus exists on how to determine suitability for W+W. The MCL Biobank Observational Study was set up to capture clinical behaviour across the United Kingdom and to characterise patients enrolled to W+W compared to those who receive upfront systemic therapy. The study remains open to recruitment. Method: From January 2015 to April 2017 222 patients from 49 centres in the United Kingdom enrolled to the study. All new MCL diagnoses compatible with WHO diagnostic criteria were eligible, with no specific exclusion criteria. Baseline data was recorded at entry including investigator decision to start systemic therapy or enter W+W. Clinical updates were provided at 6 month intervals. In contrast to previous studies W+W was defined as a period lasting at least 1 year from date of diagnosis. Results: All patients were followed-up for a minimum of 1 year. The median age was 70 (range 32-90), 69.4% were male and 47.1% were MIPI high risk. At 1 year follow-up 60 patients (27.0%) were on W+W, 141 (63.5%) received systemic therapy, 16 (7.2%) received isolated radiotherapy and 5 (2.3%) received palliative care. At 2 year follow-up 16 of 85 patients (18.9%) remained on W+W. There were no deaths recorded in patients on W+W. Estimated 2-year survival of the whole population was 80.6%. Univariate analysis comparing baseline characteristics of patients on W+W with those receiving systemic therapy showed no significant difference in age (median age 71.7 vs 69.0; p=0.48), baseline WCC (median 8.0 x 109/L vs 8.9 x 109/L; p=0.09) or performance status (ECOG >1 OR 0.7; p=0.51) meaning the MIPI was not predictive of suitability for W+W (MIPI high risk OR 1.18; p=0.61). Positive predictors for W+W included measures of low disease proliferation: LDH ratio Conclusion: This study demonstrates that adoption of W+W in the United Kingdom significantly exceeds use in previous observational studies and highlights a fundamental shift in clinical approach. The results show that conservative management can be reasonably adopted in a significant proportion of patients. Patients with low disease burden appear best candidates and markers of cell turnover may aid clinical judgement. The MIPI does not have a role in this setting. Longer follow-up will establish if W+W confers survival benefit. Disclosures Pettitt: Celgene: Research Funding; AstraZeneca: Research Funding; Roche: Research Funding; Gilead: Research Funding; Napp: Research Funding; GSK/Novartis: Research Funding; Chugai: Research Funding. Rule:Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Roche: Honoraria; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences, Inc.: Membership on an entity's Board of Directors or advisory committees; Celltrion: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees.

Introduction: Tirabrutinib (TIRA; GS/ONO-4059) is a Bruton's tyrosine kinase (BTK) inhibitor. Idelalisib (IDELA), a first-in-class phosphatidylinositol-3-kinase delta (PI3Kδ) inhibitor, is approved for the treatment of CLL. Entospletinib (ENTO) is a selective inhibitor of spleen tyrosine kinase (SYK). All three have single agent activity in CLL and updated results from TIRA monotherapy and the combinations of TIRA+IDELA and TIRA+ENTO from this ongoing phase 1b study (NCT02457598) are reported here. Methods: Patients with previously treated CLL and no prior exposure to targeted inhibitors were eligible for enrollment. For the TIRA+IDELA combination, patients were treated with dose levels in a 3+3 approach combining either idelalisib 50 mg BID or 100mg QD and TIRA ranging from 20mg to 80mg QD. For the TIRA+ENTO combination, patients were treated with entospletinib at either 200mg or 400mg QD and tirabrutinib ranging from 40mg to 80mg QD in dose levels with a 3+3 approach. TIRA monotherapy was with 80mg QD. Results: As of March 5, 2018, total of 50 CLL patients have been enrolled, 26 patients in the TIRA monotherapy group, 14 in the TIRA + IDELA group, and 10 patients in the TIRA + ENTO group. The median number of prior therapies is 1 (range 1-6). No MTD was identified for either combination at the doses evaluated and activity was high at all dose levels. For the 25 patients who have received at least one dose of TIRA monotherapy, the median duration of treatment is 28 weeks (range 0.3-54.1), and 22 patients are still on treatment. All 12 patients evaluable for response per IWCLL2008 criteria achieved a partial response on study with best overall response shown in table 1. Treatment-emergent adverse events (TEAE) were reported in 92% patients, with 28% having a ≥grade 3 TEAE. The most common TEAEs (any grade/≥grade 3) were diarrhoea (24%/0), constipation (20%/0), neutropenia (16%/12%), contusion (12%/0), asthenia (12%/0), ecchymosis (12%/0), and nausea (12%/0). AEs led to treatment interruption in 3 patients and discontinuation in 2 patients and there were no deaths in this group on study. For the 14 patients in the TIRA+IDELA group, the median duration of treatment is 100 weeks (range 36-134.9), and 11 patients are still on treatment. 12/13 evaluable patients achieved a response on study with best overall response shown in table 1. TEAEs were reported in all patients with 64% of patients having a ≥grade 3 TEAE. The most common TEAEs (any grade/≥grade 3) were diarrhoea (43%/7%), neutropenia (36%/36%), bronchitis (36%/0), rash (36%/0), back pain (29%/0), dyspepsia (29%/0), nausea (29%/0), cough (29%/0), constipation (29%/0), arthralgia (29%/0), pruritus (29%/0). AEs led to interruption or discontinuation of all study treatment in 5 and 1 patients, respectively. One patient died due to sudden respiratory difficulty not believed to be related to study treatment. For the 10 patients in the TIRA+ENTO group, the median duration of treatment is 82 weeks (range 57.1-93.9) and all patients are still on treatment. All patients achieved a partial response on study with best overall response shown in table 1. TEAEs were reported in all patients with 60% having a ≥grade 3 TEAE. The most common TEAEs (any grade/≥grade 3) were contusion (50%/0), fatigue (50%/0), diarrhoea (40%/0), upper respiratory tract infection (40%/10%), rhinitis (30%/0), alanine aminotransferase increased (30%/10%), cough (30%/0), and dyspepsia (30%/0%). AEs led to interruption or discontinuation of all study treatment in 4 and 0 patients respectively. Conclusion: Tirabrutinib in combination with idelalisib or entospletinib at the doses evaluated was tolerable with no significant potentiation of already characterized side effects from the single agents such as bleeding, diarrhea or cytopenias. Both combinations showed a high level of activity in CLL and are currently being evaluated in Phase 2 studies. Disclosures Danilov: Bayer Oncology: Consultancy, Research Funding; Aptose Biosciences: Research Funding; TG Therapeutics: Consultancy; Verastem: Consultancy, Research Funding; Astra Zeneca: Consultancy; Genentech: Consultancy, Research Funding; Takeda Oncology: Research Funding; Gilead Sciences: Consultancy, Research Funding. Herbaux:Gilead Sciences, Inc.: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. Dyer:Gilead Sciences, Inc.: Honoraria, Research Funding. Hillmen:Celgene: Research Funding; F. Hoffmann-La Roche Ltd: Research Funding; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead Sciences, Inc.: Honoraria, Research Funding; Pharmacyclics: Research Funding; Acerta: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; Alexion Pharmaceuticals, Inc: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Rule:Kite: Membership on an entity's Board of Directors or advisory committees; Celltrion: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences, Inc.: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau. Huang:Gilead Sciences, Inc.: Employment. Mitra:Gilead Sciences, Inc.: Employment. Karlin:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support. Fegan:Napp: Honoraria; Abbvie: Honoraria; Gilead Sciences, Inc.: Honoraria; Roche: Honoraria; Janssen: Honoraria.

Background: Mantle cell lymphoma (MCL), an aggressive B-cell non-Hodgkin lymphoma, remains incurable with standard therapies. The highly selective, potent Bruton tyrosine kinase (BTK) inhibitor acalabrutinib was approved by the US Food and Drug Administration for the treatment of relapsed/refractory MCL based on clinical data showing a high rate of durable responses and a favorable safety profile (Lancet 2017;391:659-667). Here, we present long-term follow-up in these patients. Methods: Eligible patients were aged ≥18 years, had confirmed MCL, Eastern Cooperative Oncology Group performance status ≤2, and had relapsed and/or were refractory to 1-5 prior therapies. Exclusion criteria included prior BTK or BCL-2 inhibitor exposure and concomitant warfarin or equivalent vitamin K antagonists. Oral acalabrutinib 100 mg twice daily was administered until progressive disease or unacceptable toxicity. Response was assessed by investigators based on the Lugano classification (J Clin Oncol 2014;32:3059-3068).Analysis of minimal residual disease using next-generation sequencing (10-6) is ongoing for a subset of patients with available samples and will be presented upon completion. Results: A total of 124 patients were treated; 80% were men, and median age was 68 years (range, 42-90 years) with 65% aged ≥65 years. At baseline, 93% of patients had Eastern Cooperative Oncology Group performance status ≤1, 8% had bulky lymph nodes ≥10 cm, 72% had extranodal involvement, and 44%/17% had intermediate-/high-risk simplified MCL International Prognostic Index scores. The median number of prior therapies was 2 (range, 1-5); 24% were refractory to the most recent prior treatment. As of February 12, 2018, median time on study was 26.3 months (range, 0.3-35.1 months), and 40% of patients remain on treatment. Median relative dose intensity (ratio of actual to planned cumulative dose during drug exposure period) was 99% (range, 27%-100%). Investigator-assessed overall response rate was 81% (95% CI: 73%, 87%), with 43% (95% CI: 34%, 52%) achieving complete response (Table). Overall response rates were consistent across prespecified subgroups of tumor bulk, presence of refractory disease and number/type of prior treatment. Median duration of response was 25.7 months (95% CI: 17.5 months, not reached). Median progression-free survival (PFS) was 19.5 months (95% CI: 16.5 months, 27.7; Figure). Median overall survival (OS) was not reached; the estimated 24-month OS rate was 72% (95% CI: 64%, 80%). The most frequent adverse events (AEs; ≥20%) were primarily Grade 1/2 and included headache (38%), diarrhea (36%), fatigue (28%), cough (22%) and myalgia (21%). Grade 3/4 AEs (≥5%) included anemia (10%), neutropenia (10%) and pneumonia (6%). There were 13 patients (10%) with 16 cardiac events, including 4 Grade 3/4 events (3%) in 1 patient each (acute coronary syndrome, acute myocardial infarction, cardiorespiratory arrest, coronary artery disease). Four patients had hypertension events (3%); 1 event was Grade 3. The most common bleeding events were contusion (13%) and petechiae (9%); all bleeding events were Grade 1/2 except for 3 Grade 3 events (gastrointestinal hemorrhage, hematuria, hematoma). Grade 3/4 infections occurred in 15% of patients and none were Grade 5; there was one case of cytomegalovirus viremia and one case of pneumocystis jiroveci pneumonia (both Grade 2). Treatment discontinuation was primarily due to progressive disease (n=54; 44%) and AEs (n=10; 8%).Twelve AEs led to discontinuation in 10 patients; all of these AEs occurred in only 1 patient each.There were 43 deaths (35%), most commonly from progressive disease (n=29; 23%) or AEs (n=6; 5%). Deaths due to AEs included bilateral pulmonary embolism, critical aortic stenosis, myelodysplastic syndrome, pneumonia, suicide, and non-small cell lung cancer; none were considered to be related to acalabrutinib. Conclusion: Response to acalabrutinib remained consistent during long-term (>24-month) follow-up, including high response rates, median PFS of 19.5 months, and a median OS that has not yet been reached, confirming efficacy in patients with relapsed/refractory MCL. The AE profile was largely similar to earlier reporting, with limited additional safety events observed with an additional year of follow-up. Disclosures Wang: Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Dava Oncology: Honoraria; AstraZeneca: Consultancy, Research Funding; Pharmacyclics: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno: Research Funding; MoreHealth: Consultancy; Acerta Pharma: Honoraria, Research Funding; Kite Pharma: Research Funding; Novartis: Research Funding. Rule:Celltrion: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences, Inc.: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Roche: Honoraria; Kite: Membership on an entity's Board of Directors or advisory committees. Zinzani:Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; TG Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; PFIZER: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Speakers Bureau; Takeda: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Speakers Bureau; SERVIER: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celltrion: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bayer: Membership on an entity's Board of Directors or advisory committees; TG Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; PFIZER: Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; MSD: Honoraria, Speakers Bureau. Casasnovas:MSD: Honoraria; Merck: Honoraria; Takeda: Honoraria; Roche: Honoraria; Gilead Sciences: Research Funding; Roche: Research Funding; Janssen: Consultancy; Gilead Sciences: Consultancy; MSD: Consultancy; merck: Consultancy; takeda: Consultancy; Roche: Consultancy; Gilead Sciences: Honoraria; Janssen: Honoraria; Celgene: Honoraria. Smith:Genentech: Research Funding; Portola: Research Funding; Pharmacyclics: Research Funding; Merck Sharpe Dohme and Corp: Consultancy, Research Funding; Seattle Genetics: Research Funding; Acerta Pharma BV: Research Funding. Morschhauser:BMS: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Other: Scientific Lectures; Epizyme: Consultancy; Roche: Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees. Panizo:Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees; Acerta Pharma: Research Funding; Roche: Consultancy, Speakers Bureau. Davies:Janssen: Consultancy, Honoraria; Karyopharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Honoraria, Research Funding; Acerta Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; F. Hoffman-La Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Pfizer: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kite: Consultancy; ADC Therapeutics: Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Research Funding. Jacobsen:Seattle Genetics: Consultancy; AstraZeneca: Consultancy; Merck: Consultancy. Kater:Janssen: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Acerta/AZ: Research Funding; Genentech: Honoraria, Research Funding. Robak:Gilead: Consultancy; Janssen: Consultancy, Honoraria; AbbVie, Inc: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria. Dua:Acerta Pharma: Employment. Frigault:AstraZeneca: Employment, Equity Ownership. Izumi:Acerta Pharma: Employment, Equity Ownership, Patents & Royalties: Acerta Pharma, various patents for ACP-196. Nguyen:Acerta Pharma: Employment. Patel:Acerta Pharma: Employment, Equity Ownership. Yin:Acerta Pharma: Employment. Jurczak:European Medicines Agency: Consultancy; Astra Zeneca/Acerta: Consultancy, Research Funding; Sandoz-Novartis: Consultancy; Janssen: Consultancy, Research Funding; Gilead: Consultancy, Research Funding; Afimed: Research Funding; Bayer: Research Funding; Beigene: Research Funding; Celgene: Research Funding; Epizyme: Research Funding; Nordic Nanovector: Research Funding; Merck: Research Funding; Morphosys: Research Funding; Pharmacyclics: Research Funding; Servier: Research Funding; Roche: Research Funding; TG Therapeutics: Research Funding.

Introduction: Tirabrutinib (TIRA; GS/ONO-4059) is a selective Bruton's tyrosine kinase (BTK) inhibitor. Entospletinib is a selective inhibitor of spleen tyrosine kinase (SYK). Both have single agent activity in lymphoma and updated results from the combination of TIRA+ENTO from this ongoing phase 1b study (NCT02457598) are reported here. Methods: Patients with previously treated non-germinal-center B-cell type (non-GCB) diffuse large B-cell lymphoma (DLBCL) or two prior lines of therapy for follicular lymphoma (FL), small lymphocytic lymphoma (SLL), mantle cell lymphoma (MCL), marginal zone lymphoma (MZL), or Waldenstrom's macroglobulinemia (WM) and no prior exposure to targeted inhibitors were eligible for enrollment. Patients were enrolled using a 3+3 dose escalation design with either ENTO 200mg or 400mg QD and doses of TIRA ranging from 20mg to 160mg QD. Cohorts were subsequently enrolled at multiple dose levels to evaluate disease-specific safety and efficacy. Results: As of March 5, 2018, 72 patients have enrolled on the combination. The median age was 67.5 years (range: 30-90) and the disease subtypes for patients enrolled were non-GCB DLBCL (n=32), FL (18), MZL (5), WM (7), SLL (2), MCL (8). No maximum tolerated dose and no dose-response relationship was observed with daily dosing of both agents at the dose levels evaluated. For patients with non-GCB DLBCL (n=32), the median number of prior therapies is 3 (range 1-7). The median duration of treatment is 8 weeks (range 2-98.1) with 6 patients still on treatment. 6/27 (22%) of the evaluable patients achieved a response; best overall response is shown in table 1. For patients with indolent NHL (n=40), the median number of prior therapies is 3 (range 1-6). The median duration of treatment is 36 weeks (range 0.1-116), with 29 patients still on treatment. 19/31 (61%) of the evaluable patients achieved a response with best overall response by indication shown in table 1. The most common treatment-emergent adverse events (AEs) are listed in table 2. Of the 71 patients who have received treatment on study, AEs led to treatment interruption or discontinuation of both study drugs in 10 and 1 patients, respectively. There have been 4 deaths on study, all due to disease progression. Conclusion: Once-daily dosing of TIRA up to 160 mg in combination with ENTO up to 400 mg QD was safe and well tolerated. Early results show activity in combination across all indications treated. Disclosures Salles: Novartis: Consultancy, Honoraria; Epizyme: Honoraria; Abbvie: Honoraria; Servier: Honoraria, Other: Advisory Board; Celgene: Honoraria, Other: Advisory Board, Research Funding; Pfizer: Honoraria; Merck: Honoraria; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; Gilead: Honoraria, Other: Advisory Board; BMS: Honoraria, Other: Advisory Board; Morphosys: Honoraria; Acerta: Honoraria; Janssen: Honoraria, Other: Advisory Board; Servier: Honoraria; Takeda: Honoraria; Amgen: Honoraria. Dyer:Gilead Sciences, Inc.: Honoraria, Research Funding. Hodson:Gilead Sciences, Inc.: Research Funding. Ysebaert:Roche: Consultancy, Research Funding; Gilead Sciences, Inc.: Consultancy, Research Funding; Janssen: Consultancy, Research Funding. Cartron:Sanofi: Honoraria; Celgene: Consultancy, Honoraria; Janssen: Honoraria; Roche: Consultancy, Honoraria; Gilead Sciences: Honoraria. Davies:Acerta Pharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead Sciences, Inc.: Honoraria, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Research Funding; ADC-Therapeutics: Research Funding; Janssen: Honoraria; Karyopharma: Membership on an entity's Board of Directors or advisory committees. Danilov:Aptose Biosciences: Research Funding; Gilead Sciences: Consultancy, Research Funding; Verastem: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Bayer Oncology: Consultancy, Research Funding; Takeda Oncology: Research Funding; TG Therapeutics: Consultancy; Astra Zeneca: Consultancy. Fegan:Roche: Honoraria; Abbvie: Honoraria; Gilead Sciences, Inc.: Honoraria; Napp: Honoraria; Janssen: Honoraria. Huang:Gilead Sciences, Inc.: Employment. Mitra:Gilead Sciences, Inc.: Employment. Rule:Roche: Honoraria; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences, Inc.: Membership on an entity's Board of Directors or advisory committees; Celltrion: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau. Morschhauser:Janssen: Other: Scientific Lectures; Epizyme: Consultancy; Roche: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Background: Bruton's tyrosine kinase (BTK) has a key role in B-cell receptor mediated pathways that are implicated in the pathogenesis of several B-cell malignancies. Inhibition of BTK has been shown to block several B-cell functions, including proliferation, antigen presentation, antibody production and cell migration. Small molecule BTK-inhibitors (BTKi) have been approved for the treatment of several B-cell malignancies, including resistant/refractory chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), and Waldenström's macroglobulinemia (WM). M7583 is a potent and highly selective BTKi, which is currently being investigated in a two-part, phase I/II trial (NCT02825836) in patients with refractory/resistant B cell malignancies. Methods: In the dose-escalation part of the study (Part 1), patients with refractory/resistant B cell malignancies received once-daily (QD) M7583 in 28-day cycles in ascending dose cohorts following an adaptive Bayesian design; the starting dose was 80 mg for 3 days followed by 160 mg (80/160 mg QD). The dose-expansion part of the study (Part 2) will investigate M7583 in patients with diffuse large B cell lymphoma (DLBCL; activated B-cell subtype) or MCL who have failed 1-3 lines of previous therapy. Here, we present safety and tumor response outcomes as assessed by the investigators according to Cheson/CLL/Owen criteria for patients in Part 1. Results: In total, 25 patients were screened for inclusion in Part 1, as of 20th May 2018 18 had received treatment with M7583 in 5 dose cohorts (80/160 mg, n=3; 300 mg QD, n=3; 600 mg QD, n=5; 300 mg BID, n=3; 900 mg QD, n=4). Treatment is ongoing in 11 patients. Patients were mostly male (72%, n=13), aged 43-80 years (median 63 years) and had a diagnosis of MCL (n=8), WM (n=4), DLBCL (n=3), marginal zone lymphoma (n=2), or small lymphocytic lymphoma (n=1). Treatment-emergent adverse events (TEAEs) occurred in 89% (n=16/18) of patients; the most common TEAE was diarrhea (n=6/18; 33%). No dose-limiting toxicities were reported. Grade ≥3 TEAEs occurred in 10 patients (56%), events in 3 (17%) were considered related to treatment. Six patients (33%) had serious TEAEs and 2 patients (11%) had treatment-related serious TEAEs. The maximum tolerated dose was not reached. Patients received M7583 for up to 20 months (median 7.9 [range 0.5-20] months). Preliminary study data show the objective response rate was 50% (9 of 18 subjects). Disease control was observed in 14 of 18 subjects (disease control rate 78%): 2 subjects had a complete response (CR), 7 subjects had a partial response (PR), 1 subjects had a minor response (MR) and 4 subjects had stable disease (SD). Responses were observed across all doses: 80/160 mg QD, 1 PR, 2 SD; 300 mg QD, 2 PR, 1 MR; 600 mg QD, 1 CR, 2 PR; 300 mg BID, 2 PR, 1 SD; 900 mg QD, 1 CR, 1 SD. Both the 300 mg BID and 900 mg QD doses met the criteria for the optimal biological dose, therefore, these doses represent potential recommended phase 2 doses in support of further development. Conclusions: Clinical benefit was observed with M7583 across the doses investigated and was well tolerated in patients with refractory/resistant B cell malignancies. These outcomes indicate a favorable benefit:risk profile for M7583. Disclosures Jurczak: TG therapeutics: Research Funding; Roche: Research Funding; Pharmacyclics: Research Funding; Merck: Research Funding; Morphosys: Research Funding; Nordic Nanovector: Research Funding; Epizyme: Research Funding; Celgene: Research Funding; Beigene: Research Funding; Bayer: Research Funding; Afimed: Research Funding; Gilead: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Sandoz-Novartis: Consultancy; Acerta: Consultancy, Research Funding; AstraZeneca: Consultancy; European Medicines Agency: Consultancy; Servier: Consultancy, Honoraria, Research Funding. Rule:Celltrion: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences, Inc.: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Kite: Membership on an entity's Board of Directors or advisory committees. Townsend:Gilead: Consultancy, Honoraria; Roche: Consultancy, Honoraria. Sarholz:Merck KGaA: Employment. Scheele:Merck KGaA: Employment. Gribben:TG Therapeutics: Honoraria; Wellcome Trust: Research Funding; Medical Research Council: Research Funding; Roche: Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Acerta Pharma: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Novartis: Honoraria; Abbvie: Honoraria; Cancer Research UK: Research Funding; Unum: Equity Ownership; Kite: Honoraria; NIH: Research Funding; Pharmacyclics: Honoraria. Zinzani:MSD: Honoraria, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; SERVIER: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astra Zeneca: Speakers Bureau; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celltrion: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Bayer: Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; PFIZER: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; PFIZER: Honoraria, Membership on an entity's Board of Directors or advisory committees; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; TG Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; TG Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees.

Background. Mantle Cell Lymphoma (MCL) drug resistance are highly dependent on B-cell-receptor signaling, Bcl-2 and the microenvironment. Ibrutinib inhibits both tumor cell proliferation and binding to the microenvironment. Venetoclax is a Bcl-2 inhibitor and Bcl-2 family members like Mcl-1 and Bcl-xL confers resistance to Venetoclax and are upregulated by the tumor microenvironment but downregulated by Ibrutinib (Touzeau, 2011, Chiron, 2015). Ibrutinib plus venetoclax has recently demonstrated high efficacy in relapsed/refractory (R/R) MCL (Tam et al NEJM 2018). Preclinical investigations show that microenvironment-dependent long-term expansion and drug resistance to venetoclax are counteracted by obinutuzumab (type II glycoengineered humanized anti-CD20 antibody) and obinutuzumab/venetoclax/ibrutinib is highly active against primary MCL cells. (Chiron Blood 2016). All together these findings gave the rational to investigate Obinutuzumab/Ibrutinib (step A) and Obinutuzumab/Venetoclax/Ibrutinib (step B) combinations. The OAsIs trial (NCT02558816) has been designed to assess the safety, tolerability and efficacy of these two combos in R/R MCL. DLTs were assessed during the first 2 months (step A) and 3 months (step B) of treatment. Methods: Oasis is a multicenter, non-randomized, phase I study. Step A evaluates the safety of obinutuzumab (1000mg IV C1D1, 8,15, C2-6 D1 and every 2 months until C24) plus Ibrutinib (560mg/d until progression) (n=9). Step B primary objective is to determine the MTD of obinutuzumab/venetoclax/ibrutinib. Venetoclax is administered from C2 (C2W1 100mg/d, C2W2 200mg/d, C2W3 400mg/d and C2W4-C6: 400, 600 or 800mg/d). A continual reassessment method is used to allocate venetoclax doses (3 patients-pts- per dose-level). Enrolment in step A and B for R/R MCL started in November 2015 and October 2016, respectively. Results. Step A (Obinutuzumab/Ibrutinib) (n=9). Median age at inclusion was 64y (range 58-82) and median lines of treatment prior to inclusion is 1 (1-4), including ASCT in 7 patients and allo-SCT in one case. Median time from diagnosis to C1D1 is 46.5m (18.4-103). Two pts presented with blastoid variant. One of nine step A patients presented TP53 mutation. Median time from diagnosis to C1D1 is 46.5m (18.5-103). During the first 3 months of treatment, there was no clinically relevant non-hematological grade 3-4 AEs. Eight grade 3-4 hematological AEs were reported in 4 pts (lymphopenia 4 ; neutropenia 4 ; thrombocytopenia 1). One patient progressed at end of C2 and died few weeks later while 7 (87%) were in CR according to Lugano criteria at end of C6. MRD status was assessed by ASO qPCR targeted to clonal immunoglobulin rearrangements in 6 /9 step A pts (one progressed before C6, data missing = 2). Of these, 4 were MRD negative in both blood and bone marrow after C6 (one remained MRD pos with no clinical relapse and underwent allo-SCT, one was not evaluated in BM). At the 12 months time point, the 3 evaluated pts remained MRD negative. With a median follow-up of 23,5m (8,9-31.6), 8 pts are alive (6 completed the 2y treatment program and are in CR). Step B (Obinutuzumab/ Ibrutinib/Venetoclax; Ven 400mg (n=3); at Ven=600mg (n=3) and Ven=800mg (n=6)). Median age at inclusion is 64.5y (range 45-74). Median lines of treatment prior inclusion is 2 (1-3), including ASCT in 8 patients. Five pts presented with blastoid MCL. TP53 status was assessed in 3/10 pts (2 ongoing). Of these 10, 3 presented TP53 mutations. Median time from diagnosis to C1D1 is 50.2m (12.8-123). The median follow-up for living pts (n=8) is 6.5m (2.5-15). During the first three months of treatment, there was no clinically relevant non-hematological grade 3-4 AEs. Twenty-nine grade 3-4 hematological AEs were reported in 7 pts (febrile neutropenia 1, neutropenia 4 ; thombopenia 4, anemia 2 and lymphopenia 3). At end of C2 , 3 achieved CR, 5 PR and 4 pts had PD. Among 9 pts assessed after C6, 5 patients were in CR (MRD analysis ongoing) Conclusion. No DLT has been reported in both step A and B. Both combinations are well tolerated and provide high disease control including CR at the molecular level. Oasis step C (obinutuzumab/venetoclax/ibrutinib) for untreated MCL pts is now open for inclusion since July 2018. Disclosures Le Gouill: Roche: Consultancy, Honoraria; Janssen-Cilag: Consultancy, Honoraria. Morschhauser:BMS: Membership on an entity's Board of Directors or advisory committees; Janssen: Other: Scientific Lectures; Epizyme: Consultancy; Roche: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees. Cartron:Sanofi: Honoraria; Janssen: Honoraria; Gilead Sciences: Honoraria; Roche: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Gastinne:Millennium/Takeda: Honoraria. Davies:Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta Pharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead Sciences, Inc.: Honoraria, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Research Funding; ADC-Therapeutics: Research Funding; Janssen: Honoraria; Karyopharma: Membership on an entity's Board of Directors or advisory committees. Herbaux:Gilead Sciences, Inc.: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. Rule:Kite: Membership on an entity's Board of Directors or advisory committees; Celltrion: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences, Inc.: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau.

Background: Mantle cell lymphoma (MCL) remains challenging particularly in the relapsed/refractory setting, where patients often show chemoresistance. Novel molecular-based therapies have shown impressive and durable activity in that setting, although primary and acquired resistance remains problematic. A recent retrospective series of 114 patients who had failed ibrutinib (median of 4.7 month exposure) showed very short median overall survival of 2.9 months after ibrutinib cessation (Martin et al. Blood 2015). Here we report the results from the observationalMCL-004 study investigating outcomes of patients treated with lenalidomide (an IMiD® immunomodulatory agent) after failing ibrutinib; patients were either relapsed, progressed, refractory, or intolerant to ibrutinib. The objective here is to evaluate the clinical effectiveness of lenalidomide monotherapy or a lenalidomide-containing regimen in relapsed/refractory MCL after ibrutinib failure or intolerance. Methods: MCL-004 is a multicenter study in patients with MCL who relapsed/progressed after or were refractory/intolerant to ibrutinib, and were subsequently treated with lenalidomide. With patient informed consent, data were collected retrospectively from patients who, after their disease failed to respond to ibrutinib, received lenalidomide-based therapy from March 1, 2009 to June 9, 2015. The primary endpoint was investigator-assessed overall response rate (ORR) based on 2007 International Working Group criteria, with required patient monitoring and routine imaging. Results: Thirty patients were enrolled at 7 US sites and 1 EU site, including patients receiving lenalidomide monotherapy (n=8), lenalidomide + rituximab (n=8), and lenalidomide + other treatment (n=14). Lenalidomide + other treatment included combination with rituximab, carfilzomib, and dexamethasone (n=3); other combinations were given in ≤2 patients. Patients had a median age of 69 years (range, 50-84), and median time from last dose of ibrutinib to first dose of lenalidomide was 1.3 weeks (range, 0.1-21.7). All patients received ≥2 prior lines of therapy, and 83% received ≥3 prior therapies (median prior therapies, 3.5; range, 2-8). With prior ibrutinib, the best responses achieved were 10% complete response (CR), 43% partial response (PR), 3% stable disease, 40% relapse/progressive disease (PD), and 3% unknown. Primary reasons for ibrutinib discontinuation were 50% relapse/PD, 40% refractory, and 10% intolerance. Patients received a median of 2 cycles (range, 1-11) of lenalidomide-based treatment. Eight patients' disease responded (4 CR, 4 PR), resulting in an ORR of 27% (95% CI, 12%-46%). Five of 8 maintained their response at data cut-off (3 CR, 2 PR). ORR was similar for patients with relapse/PD vs. those refractory to ibrutinib (29% vs. 33%, respectively). Median duration of response (DOR) was 18 weeks (95% CI, 2.9-25+) for all patients. Median DOR was not reached in patients who previously relapsed/progressed with ibrutinib compared with a median of 11 weeks for those whose disease was refractory to ibrutinib. Most common treatment-emergent adverse events (TEAEs) were 33% fatigue; 27% nausea; and 23% each dyspnea, neutropenia, dizziness, or rash. In general, TEAEs were less common with lenalidomide monotherapy. The most frequently reported serious AEs were pneumonia, dyspnea, deep vein thrombosis, hypotension, and acute kidney injury (7% each). At data cutoff, 15 patients (50%) had died, mostly due to MCL and none due to second primary malignancy. Conclusions: Most patients received ≥3 prior lines of treatment, and median time from last dose of ibrutinib to first dose of lenalidomide was short. Lenalidomide-based treatment showed clinical activity in this difficult-to-treat patient population, including 27% ORR and 13% CR. No new safety signals for lenalidomide were identified. Overall, our results show that lenalidomide is active in a selected group of patients with relapsed/refractory MCL that previously failed ibrutinib. Disclosures Wang: BeiGene: Research Funding; Asana BioSciences: Research Funding; Acerta Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Celgene: Research Funding; Kite Pharma: Research Funding; Juno Therapeutics: Research Funding; Onyx: Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Martin:Acerta: Consultancy; Teva: Research Funding; Novartis: Consultancy; Janssen: Consultancy, Honoraria, Other: travel, accommodations, expenses; Celgene: Consultancy, Honoraria; Gilead: Consultancy, Other: travel, accommodations, expenses. Goy:Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria, Other: Writing support, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding; Johnson & Johnson: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; infinity: Consultancy, Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; Acerta: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Hamadani:Takeda: Research Funding. Ghosh:Gilead: Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; SGN: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Genentech: Research Funding; TG Therapeutics: Research Funding. Reeder:Millennium: Research Funding; BMS: Research Funding; Celgene: Research Funding; Novartis: Research Funding. Barnett:Celgene Corporation: Employment, Equity Ownership. Casadebaig Bravo:Celgene: Employment, Equity Ownership. Schuster:Pharmacyclics: Consultancy, Research Funding; Novartis: Research Funding; Gilead: Research Funding; Janssen Research & Development: Research Funding; Nordic Nanovector: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Research Funding; Genentech: Consultancy; Hoffman-LaRoche: Research Funding.

Introduction: Central nervous system (CNS) relapse of diffuse large B-cell lymphoma (DLBCL) represents a major clinical challenge and is fatal in most patients. Recently Schmitz et al (J ClinOncol 2016), defined an effective risk model, the CNS-IPI, to identify those at highest risk of CNS relapse, based on the international prognostic index (IPI) score and presence of renal or adrenal involvement. For DLBCL patients receiving R-CHOP-like regimens +/- intrathecal methotrexate, the risk of CNS relapse for low, intermediate and high-risk patients was Aim: To assess CNS relapse rates in an intermediate-high risk cohort of patients with DLBCL treated with the R-CODOX-M R-IVAC regimen, incorporating multiple CNS-penetrating agents. Methods: Patients with newly diagnosed DLBCL and an IPI score ≥3 were enrolled in a prospective, multi-centre, phase 2 trial (McMillan et al, Hematol Oncol 2015; 31(S1), 130a) and treated with modified CODOX-M and IVAC, including high dose intravenous methotrexate, cytarabine, ifosfamide and etoposide with 8-12 intrathecal injections (Mead et al, AnnOncol 2002; 23(8):1264-74); plus 8 doses of rituximab. The primary endpoint was progression-free survival (PFS). CNS involvement was diagnosed according to neurological signs, radiological findings and/or demonstration of malignant lymphocytes within the cerebrospinal fluid. Involvement ofextranodal sites was prospectively documented at registration and at relapse. Presence of CNS, adrenal and renal involvement was confirmed using case report forms prior to this post hoc analysis. Results: 108 patients were treated at 32 UK sites between May 2008 and April 2013. Median age was 50 years (18-65 years). Eight patients (7.4%) had CNS involvement at baseline. Eighty-two patients (75.9%) received 4 cycles of treatment. At a median follow-up of 45 months, PFS and overall survival were 65.5% (95% CI: 55.5 - 73.8) and 73.7% (64.0 - 81.2), respectively. Progression or relapse within the CNS occurred in 5 patients (4.6%; Table 1) at a median of 5.5 months after registration (0.9-9.1 months). All patients died within 9 months of CNS relapse, 4 due to DLBCL and one treatment-related death. Excluding those with CNS involvement at baseline or incomplete information (n=4; 2 with missing baseline information (no CNS relapse) and 2 awaiting confirmation of CNS status at relapse), CNS-IPI was evaluable in 96 patients, of which 95% had an elevated LDH, 57% had a performance status of ≥2, and 8% were ≥60 years. All patients had stage III-IV disease, 76% had >1 extranodalsite and 27% had renal or adrenal involvement. Forty-one patients (43%) were intermediate risk (2-3 factors) and 55 (57%) were high risk (4-6 factors) for CNS relapse. 2-year CNS relapse rates were 0% for intermediate risk and 6.2% (2.0 - 18.1) for high risk patients (Figure 1). Of the 3 CNS relapses in high risk patients, 2 occurred concurrently with systemic relapse; there was only one episode of isolated CNS relapse. Of the 8 patients with CNS involvement at baseline, 2 (25%) developed CNS relapse, including 1 isolated CNS relapse. One further patient died of refractory DLBCL whilst 5 (62.5%) are alive and progression free with a minimum of 28 months follow-up. Conclusions: Inclusion of CNS-directed therapy intrinsic to the R-CODOX-M IVAC regimen resulted in very low rates of CNS relapse. Although patient numbers and low event rates make direct comparison difficult, results appear promising alongside historical results with R-CHOP chemotherapy. CNS relapse rates for both intermediate and high risk patients in this trial were below the 95% confidence intervals for CNS relapse reported in large training and validation cohorts by Schmitz et al (0% vs 2.2 - 4.4 and 2.3 - 5.5 for intermediate risk patients and 6.2% vs 6.3 - 14.1 and 7.9 - 16.1 for high risk). Of note, only 2 patients in the whole cohort progressed with isolated CNS disease, one of whom had CNS disease at diagnosis. Thus, where systemic disease was fully treated, treatment failure due to inadequate CNS penetration was rare. Reasonable outcomes were achieved in patients with CNS involvement at diagnosis but greater patient numbers are required to further evaluate this regimen in secondary CNS lymphoma. Table 1 PFS events and CNS relapse rates Table 1. PFS events and CNS relapse rates Figure 1 CNS relapse rates according to CNS-IPI and presence of CNS disease at baseline Figure 1. CNS relapse rates according to CNS-IPI and presence of CNS disease at baseline Disclosures Phillips: Roche: Consultancy. Patmore:Roche: Honoraria; Janssen Cilag: Honoraria. Ardeshna:Roche: Membership on an entity's Board of Directors or advisory committees, Other: Conference Expenses, Research Funding. Montoto:Roche: Honoraria; Gilead: Research Funding.

Introduction:The selectiveBruton's tyrosine kinase (BTK) inhibitor GS-4059 (ONO-4509) showed remarkable efficacy and tolerability in a phase 1 multicenter dose escalation study (NCT01659255) in 28 patients with relapsed and refractory (R/R) CLL (Walter et. al. Blood 2016). No maximum tolerated dose was identified in the CLL cohort andintrasubject dose escalation was allowed. Patients discontinued study participation due to disease progression (3), adverse events (2), death (3), and investigator decision (1). Nineteen patients whocontinued to respond or derive clinical benefit from GS-4059 enrolled in the extension study (NCT02457559) in December 2015. Theupdated survival and safety data are presented here. Methods:Nine dose cohorts ranged from 20 mg OD to 600 mg OD and 300 mg BID. Patients were evaluated clinically every 4 weeks; radiographic evaluation was at or prior to enrolment, at 12 weeks, and every 24 weeks thereafter.Targeted next-generation sequencing using a custom array (SiestmasGenomicos, Valencia, Spain) was used to detect mutations in 36 CLL-related actionable genes for all 28 patients with CLL enrolled in the phase 1 study. All mutations were confirmed by Sanger sequencing. Results: As of June 1, 2016, 17 patients remain on study. Two patients discontinued study treatment, 1 due to idiopathic thrombocytopenic purpura and 1 due to progressive disease (dose 20 mg OD). The overall median duration of treatment is 799 days with a median progression-free survival of 45 months (Figure 1). There was no improvement in overall response over the course of the first 6 months of the extension study. Further updated safety analysis has not identified any new late-occurring toxicity or any reports of Richter's transformation. Bleeding-related adverse events (AEs) have all been grades 1-3. The incidence of bleeding-related events in the long-term extension study has been significantly less than in the initial 6 months of treatment (11% vs 68%). Overall,46% of patients had a maximal weight gain of grade 1-3 on study (grade 1 [5], grade 2 [3], grade 3 [5]). Maximal weight loss of grade 1-2 on study was noted in 36% of patients (grade 1 [8], grade 2 [2]). No dose reductions for toxicity have been required. Depth and duration of response were independent of interphase FISH abnormalities, mutational profile and response to last treatment prior to study entry. Nine of 28 patients initially enrolled had CLL with TP53 mutations in the presence of a TP53 deletion; 2 cases of mutation occurred independently of TP53 loss. Seven NOTCH1, 8 SF3B1, and1 POT1 mutations were identified. We did not identify a genetic subset of patients who appeared at risk of early progression. In total, 7 of 9 patients with TP53 mutation remain on therapy; 1 patient progressed and 1 died from sepsis. One patient with TP53, NOTCH1, and SF3B1 mutations has been on therapy for 1100 days, on a dose of 40 mg OD. Another patient with a TP53 mutation who progressed on 40 mg OD (March 2015) but lacked BTK and PLCG2 mutations, has achieved a partial response while on 600 mg OD dose. A second lymphocytosis similar in magnitude and duration to that seen with the initial treatment with GS-4059 was observed on dose escalation. Conclusion: GS-4059 continues to demonstrate preliminary efficacy and tolerability in the treatment of CLL, irrespective of cytogenetics or mutational profile. The response rate and depth of response in CLL are comparable to the results reported for other BTK inhibitors, and long-term treatment discontinuation rates due to AEs are low. Figure 1 Updated Progression-Free Survival Curve for CLL Patients. Figure 1. Updated Progression-Free Survival Curve for CLL Patients. Disclosures Walter: Gilead Sciences: Other: Contribution to travel expenses to conference. Cartron:Roche: Consultancy, Honoraria; Celgene: Honoraria; Gilead: Honoraria; Jansen: Honoraria. Morschhauser:Gilead Sciences: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Servier: Consultancy, Honoraria; Janssen: Honoraria. Fegan:Gilead Sciences: Honoraria; Roche: Honoraria; AbbVie: Honoraria. Yang:Gilead Sciences: Employment, Equity Ownership. Mitra:Gilead Sciences: Employment, Equity Ownership. Dyer:ONO Pharmaceuticals: Research Funding; Gilead Sciences: Consultancy, Other: Travel funding, Research Funding, Speakers Bureau; Roche: Consultancy, Speakers Bureau. Salles:Janssen: Consultancy, Honoraria; Gilead: Honoraria, Research Funding; Celgene: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Mundipharma: Honoraria; Roche/Genentech: Consultancy, Honoraria, Research Funding.

Introduction: Inhibitors of signaling downstream of the B-cell receptor have a demonstrated clinical benefit in a number of lymphoid malignancies but generally require chronic therapy with the potential for single mutations to lead to resistance. GS-4059 (ONO-4059) is a Bruton's tyrosine kinase (BTK) inhibitor. GS-4059 is safe and tolerable as a single agent at doses up to 480 mg in non-Hodgkin lymphoma and up to 600 mg in chronic lymphocytic leukemia (CLL). Idelalisib, a phosphatidylinositol-3-kinase delta (PI3Kd) inhibitor, is approved for the treatment of CLL. Single-agent therapy leads to durable responses, but with limited depth of response; treatment with a combination of GS-4059 and idelalisib has the potential to lead to deeper and more durable responses at lower doses of individual agents than needed as monotherapy. Methods:This ongoing, phase 1b study (NCT02457598) is evaluating the safety and tolerability of GS-4059 in combination with idelalisib. Patients with previously treated CLL, FL, small lymphocytic lymphoma (SLL), mantle cell lymphoma (MCL), marginal zone lymphoma (MZL), Waldenstrom's macroglobulinemia (WM), or non-germinal-center B-cell type (non-GCB) diffuse large B-cell lymphoma (DLBCL) and no prior exposure to BTK or PI3Kd inhibitors eligible for enrollment. Patients are enrolled using a 3+3 dose escalation design with a fixed dose of idelalisib (50 mg BID) and increasing doses of GS-4059. Optional dose expansion cohorts of up to 30 patients can be enrolled to generate disease-specific data. Patients were observed for a 28-day period to identify dose-limiting toxicities (DLTs). Efficacy evaluation was performed at 6-week intervals for DLBCL, 24-week intervals for CLL, and 12-week intervals for all other indications. Results: As of June 1, 2016, 20 patients have enrolled; the median age was 64 (37-79) years and 65% were men. The disease subtypes enrolled were CLL (n = 8), FL (5), MZL (2), SLL (2), and 1 each with DLBCL, MCL, and WM. The median number of prior therapies is 2.5 (range 1-4). The median duration of treatment is 113 days (range 29-310) with 17 patients still on-treatment. Three patients discontinued all study treatment due to disease progression (FL, MZL, DLBCL). There has been 1 death on study following progressive disease. Two DLTs of neutropenia were observed at dose level 2B (GS-4059 20 mg BID/idelalisib 50 mg BID), prompting the decision to discontinue the evaluation of twice-daily administration of GS-4059 when combined with idelalisib. The maximum tolerated dose (MTD) was not reached in Arm A of the study (Table 1). Of the 20 patients enrolled, 95% reported a treatment-emergent AE (TEAE), of which 55.0% were ≥grade 3. The only ≥grade 3 TEAE that was present in more than 1 patient was neutropenia. The most common TEAEs are listed in Table 2. Grade 3 liver laboratory test abnormalities were observed in 1 patient after approximately 5 months of treatment; a liver biopsy revealed a lymphocytic infiltrate consistent with CLL. Dose interruption due to an AE was reported in 45% of patients. Aside from 2 patients who discontinued idelalisib due to neutropenia and restarted therapy on GS-4059 alone, all patients successfully re-initiated therapy with both agents after treatment interruption. Nine patients have been on study for ≥24 weeks with 7 patients evaluable for radiographic response; 3 patients have had a >50% decrease in lymphadenopathy (CLL, SLL, FL). Preliminary pharmacokinetic (PK) results indicate that idelalisib at the evaluated dose levels does not significantly alter the PK of GS-4059. Conclusion: Once-daily dosing of GS-4059 up to 80 mg in combination with idelalisib 50 mg BID was generally safe and well tolerated. Early results show efficacy at combination doses significantly below the MTD for either single agent. This data supports continued clinical evaluation of the combination of GS-4059 and idelalisib for the treatment of B-cell malignancies. Disclosures Salles: Mundipharma: Honoraria; Novartis: Consultancy, Honoraria; Roche/Genentech: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Gilead: Honoraria, Research Funding; Celgene: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Morschhauser:Celgene: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Gilead Sciences: Consultancy, Honoraria; Janssen: Honoraria; Servier: Consultancy, Honoraria. Cheson:Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Research Funding. Fegan:AbbVie: Honoraria; Roche: Honoraria; Gilead Sciences: Honoraria. Nelson:Gilead Sciences: Employment, Equity Ownership. Yang:Gilead Sciences: Employment, Equity Ownership. Mitra:Gilead Sciences: Employment, Equity Ownership. Starodub:Bayer: Consultancy; BMS: Speakers Bureau; Sandoz: Consultancy. Dyer:Roche: Consultancy, Speakers Bureau; ONO Pharmaceuticals: Research Funding; Gilead Sciences: Consultancy, Other: Travel funding, Research Funding, Speakers Bureau.

Between August 1985 and July 1994, we performed 115 volunteer unrelated donor (VUD) bone marrow transplants (BMT) for first chronic phase (n = 86) or advanced phase (n = 29) chronic myeloid leukemia (CML). Standard serologic HLA typing of potential donors and recipients was supplemented with one-dimensional isoelectric focusing (IEF) for class I proteins, allogenotyping for DR and DQ alleles using DNA restriction fragment length polymorphism (RFLP) analysis, and the measurement of antirecipient major histocompatibility complex (MHC) cytotoxic T- lymphocyte precursor cells in the donors' blood (CTLp assay). Recipients were conditioned for transplantation with a combination of high-dose chemotherapy and total body irradiation (n = 103) or high- dose chemotherapy alone (n = 12). Twenty eight recipients received ex vivo T-cell-depleted marrow, and 84 underwent some form of in vivo T- cell depletion. The probability of severe (grades III or IV) acute graft-versus-host disease (aGVHD) was 24%, and that of extensive chronic graft-versus-host disease (cGVHD), 38%. Proportional hazards regression analysis showed an association between low frequency CTLp and a reduced incidence of severe aGVHD (relative risk [RR], 0.28; P = .0035). The probability of relapse at 3 years was 23%, with first chronic phase disease being independently associated with a lower risk of relapse (RR, 0.71; P = .01). The overall leukemia-free survival (LFS) at 3 years was 37%; the LFS for the first chronic phase and advanced phase recipients was 41% and 26%, respectively. First chronic phase disease (RR, 0.56; P = .063) and the combination of recipient cytomegalovirus (CMV) seronegativity and an IEF-matched donor (RR, 0.48; P = .011) were both associated with improved LFS. The probabilities of survival and LFS for patients under 40 years of age transplanted in first chronic phase from an IEF-matched donor were 73% and 50%, respectively. We conclude that VUD BMT is a reasonable option for patients with CML; when using ex vivo or in vivo T-cell depletion, optimal results are achieved in patients transplanted in chronic phase with marrow from donors without demonstrable class I HLA mismatch and a low CTLp frequency.

Introduction MCL is an incurable aggressive B-cell lymphoma with a poor overall prognosis. For patients with MCL who fail initial therapy (ie, with relapsed or refractory [R/R] disease), treatment options historically have been limited. While remission duration is generally short, the goal of therapy has been to achieve remission while balancing treatment-related toxicities. Consequently, a substantial proportion of patients continuously suffer from lymphoma symptoms and other disease signs, such as itching and trouble sleeping or concentrating. Additionally, worries and high emotional sensitivity lead to reduced functional status and well-being. Therefore, it is crucial to any treatment to maintain and improve the functional status and well-being of patients with R/R MCL for as long as possible throughout the treatment period. Methods RAY (MCL3001) is a phase 3, randomized, open-label, multicenter study in patients with R/R MCL. Patients were randomized in a 1:1 ratio to receive ibrutinib (560 mg once daily) or temsirolimus (175 mg on days 1, 8, and 15 of Cycle 1; 75 mg on days 1, 8, and 15 of subsequent cycles). Stratification factors were the number of prior lines of therapy (1-2 vs ³3) and simplified MCL international prognostic index risk (low [0-3] vs intermediate [4-5] vs high [6-11]). Patients in both arms received treatment until disease progression or unacceptable toxicity. Primary end point of the study was progression-free survival (PFS), as assessed by an independent review committee. Lymphoma symptoms were assessed using the Functional Assessment of Cancer Therapy-Lymphoma (FACT-Lym) questionnaire lymphoma subscale. The FACT-Lym was administered before any tests, procedures, or other consultations, and was used until disease progression, death, or the clinical cutoff, whichever came first. Median time to worsening (TTW), a prespecified secondary end point, and time to clinically meaningful improvement (TTI) on the lymphoma subscale were estimated. Worsening was defined as a ≥ 5-point decrease from baseline and clinically meaningful improvement as a ≥ 5-point increase from baseline. TTW and TTI on the lymphoma subscale were examined using Kaplan-Meier methods. Results In total, 280 patients were randomized to ibrutinib (n = 139) or temsirolimus (n = 141); 253 patients (ibrutinib, n = 130; temsirolimus, n = 123) provided FACT-Lym lymphoma subscale responses at baseline. Patients were compliant to therapy, and attrition was balanced between treatment arms. Disease characteristics and demographics at baseline (including FACT-Lym lymphoma subscale scores) were also generally well balanced. The study met its primary end point with a statistically significant 57% reduction in disease progression or death (PFS) with ibrutinib versus temsirolimus (hazard ratio [HR], 0.43; 95% confidence interval [CI], 0.32-0.58; p < 0.0001). The median PFS was 14.6 months for the ibrutinib arm and 6.2 months for the temsirolimus arm. When adjusted for exposure, incidence of TEAEs was lower for the ibrutinib arm than the temsirolimus arm. The proportion of patients with worsening from baseline on the FACT-Lym lymphoma subscale was lower for ibrutinib compared with temsirolimus (26.6% vs 51.8%, respectively). Median TTW was not reached with ibrutinib versus 9.7 weeks with temsirolimus, with a statistically significant reduction in the risk of worsening of 73% (p < 0.0001; Figure 1). The proportion of patients with a clinically meaningful improvement from baseline on the FACT-Lym lymphoma subscale was higher for ibrutinib compared with temsirolimus (61.9% vs 35.5%, respectively). Median TTI was shorter for ibrutinib compared with temsirolimus (6.3 weeks vs 57.3 weeks, respectively; HR, 2.19; p < 0.0001; Figure 2). Conclusions RAY (MCL3001) is the first trial comparing different targeted approaches in R/R MCL. The presented data indicate that ibrutinib is associated with greater improvements and less worsening in lymphoma symptoms compared with temsirolimus, as measured by the lymphoma subscale of the FACT-Lym. These results suggest that the superior efficacy results and favorable safety profile of ibrutinib are accompanied by better lymphoma symptom outcomes, indicating significant clinical benefit for the majority of patients with R/R MCL. Disclosures Hess: Pfizer, Janssen, Roche, Mundipharma: Honoraria, Research Funding; Janssen, Roche, Celgene, Novartis: Consultancy. Rule:J&J: Consultancy, Other: Travel reimbursement, Research Funding; Roche: Consultancy, Other: Travel reimbursement; Celgene: Consultancy, Other: Travel reimbursement; Gilead: Research Funding. Jurczak:CELLTRION, Inc,: Research Funding. Rusconi:Roche: Honoraria. Witzens-Harig:Pfizer: Honoraria, Research Funding; Roche: Honoraria. Bandyopadhyay:Janssen: Employment. Goldberg:Janssen: Employment. Bothos:Janssen: Employment. Enny:Janssen: Employment. Vermeulen:Janssen: Employment. Traina:Janssen: Employment.

Introduction MCL is an aggressive B-cell lymphoma with a poor overall prognosis. For patients who fail initial therapy, conventional chemotherapy achieves only short-term remissions. Ibrutinib is a first-in-class, once-daily, oral, covalent inhibitor of Bruton's tyrosine kinase that has been shown to be highly active for previously treated MCL patients (overall response rate [ORR] ~65%; complete response [CR] ~20%) in single-arm phase 2 studies. Temsirolimus has demonstrated significantly longer progression-free survival (PFS) vs investigator's choice. In this phase 3, randomized, open-label study (MCL3001 [RAY]), ibrutinib was compared with temsirolimus in patients with relapsed or refractory (R/R) MCL who had received ≥1 prior rituximab-containing therapy. Methods Patients were randomized at a 1:1 ratio to receive oral ibrutinib (560 mg once-daily) or intravenous temsirolimus (175 mg: Days 1, 8, and 15 of Cycle 1; 75 mg: Days 1, 8, and 15 of subsequent cycles). Stratification factors were number of prior lines of therapy (1-2 vs ³3) and simplified MCL international prognostic index (sMIPI) risk (low [0-3] vs intermediate [4-5] vs high [6-11]). Patients in both arms received treatment until disease progression or unacceptable toxicity. Primary end point of the study was PFS, as assessed by an independent review committee (IRC). Secondary end points included ORR, overall survival (OS), time to next treatment (TTNT), time to worsening of lymphoma symptoms (measured by FACT-Lym lymphoma subscale), and safety. Results Overall, 280 patients were randomized to ibrutinib (n = 139) or temsirolimus (n = 141). Baseline disease characteristics and demographics were generally well balanced. Median age (range) was 68 years (34-88) and median number (range) of prior lines of therapy was 2 (1-9). Approximately two-thirds of the patients had intermediate- or high-risk disease. At the time of this analysis, median follow-up was 20.0 months. Ibrutinib was superior to temsirolimus for the primary end point of IRC-assessed PFS, with a statistically significant 57% reduction in the risk of progression or death (Figure 1). The median PFS was 14.6 months for the ibrutinib arm and 6.2 months for the temsirolimus arm, respectively. At a landmark of 2 years, the PFS rate is 41% in the ibrutinib arm vs 7% in the temsirolimus arm. PFS results were consistent across most assessed subgroups. Investigator-assessed PFS was consistent with the IRC results. IRC-assessed ORR was significantly higher for ibrutinib vs temsirolimus (71.9% vs 40.4%; p < 0.0001) with a CR rate of 18.7% vs 1.4%, respectively. Median OS was not reached with ibrutinib vs 21.3 months with temsirolimus, showing a positive trend toward patients in the ibrutinib arm (reduced risk of death by 24% [HR, 0.76; 95% CI, 0.53-1.09]). However, these results may have been confounded by 23% of patients that initially received temsirolimus crossing over to receive ibrutinib. A greater proportion of patients treated with ibrutinib vs temsirolimus avoided worsening of lymphoma symptoms throughout the study; 27% of ibrutinib patients had worsening vs 52% of temsirolimus patients. Median TTNT was not reached with ibrutinib vs 11.6 months with temsirolimus. Median treatment duration was 14.4 months for ibrutinib and 3.0 months for temsirolimus. Overall, 6.5% of subjects discontinued treatment due to AEs in the ibrutinib arm and 25.5% of subjects discontinued treatment due to AEs in the temsirolimus arm. The most common TEAEs with ibrutinib were diarrhea, fatigue, and cough, whereas with temsirolimus, thrombocytopenia, anemia, and diarrhea were most commonly observed (Table 1). Grade ³3 TEAEs were reported for 67.6% of ibrutinib patients vs 87.1% of temsirolimus patients; most frequent were thrombocytopenia, anemia, and neutropenia. When adjusted for exposure, TEAE incidence was consistently lower for the ibrutinib arm vs the temsirolimus arm. Conclusions Ibrutinib is superior to temsirolimus for PFS and ORR, and showed preferable tolerability. The results of this phase 3 trial confirm the efficacy and favorable safety profile of ibrutinib shown in phase 2 studies. Future concepts will investigate ibrutinib-based combination approaches for patients with R/R MCL. Disclosures Rule: Gilead: Research Funding; Celgene: Consultancy, Other: Travel reimbursement; J&J: Consultancy, Other: Travel reimbursement, Research Funding; Roche: Consultancy, Other: Travel reimbursement. Rusconi:Roche: Honoraria. Joao:Celgene, Novartis: Consultancy; Janssen, Roche: Membership on an entity's Board of Directors or advisory committees. Witzens-Harig:Pfizer: Honoraria, Research Funding; Roche: Honoraria. Hess:Pfizer, Janssen, Roche, Mundipharma: Honoraria, Research Funding; Janssen, Roche, , Celgene, Novartis: Consultancy. Balasubramanian:Janssen: Employment, Equity Ownership; Pharmacyclics LLC, an AbbVie Company: Equity Ownership. Bandyopadhyay:Janssen: Employment. Sun:Janssen/J&J: Employment, Equity Ownership. Goldberg:Janssen: Employment. Bothos:Janssen: Employment. Traina:Janssen: Employment. Enny:Janssen: Employment. Rizo:Janssen: Employment. Vermeulen:Janssen: Employment.

Introduction In 2 large phase 3 trials of patients (pts) with relapsed or refractory (R/R) CLL/SLL, single-agent ibrutinib (ibr) was superior to ofatumumab (ofa) (RESONATE; Byrd. NEJM 2013) and ibr + BR was superior to placebo + BR (HELIOS; Chanan-Khan. ASCO 2015). Both studies evaluated ibr in different pt populations with different relevant comparators (eg, ofa in pts who had relapsed following prior anti-CD20-based chemoimmunotherapy [CIT] and/or with del17p, and BR in pts eligible for CIT). In the absence of head-to-head evaluations of single-agent ibr vs BR or single-agent ibr vs ibr + BR, indirect comparisons can be used for hypothesis testing by potentially providing insights on the relative efficacy of treatments. As such, an indirect comparative analysis of data from RESONATE and HELIOS was performed. Recognizing biases inherent in cross-trial comparisons, including lack of randomization across trials and consequent differences in distributions of important confounding variables (eg, pt characteristics, prognostic factors), we used pt-level data from both studies to risk adjust for confounders using accepted multivariate statistical approaches. Methods In RESONATE, pts received 420 mg oral ibr daily until disease progression or unacceptable toxicity or intravenous ofa for up to 24 weeks. The primary end point was IRC-assessed PFS, with secondary end points of OS and ORR. In HELIOS, pts received BR (≤ 6 cycles) with either 420 mg oral ibr daily or placebo until disease progression or unacceptable toxicity. Pts with del17p were excluded. The primary end point was IRC-assessed PFS, with secondary end points of ORR and OS. Per protocol amendment in both studies, pts in comparator arms could switch to ibr upon IRC-confirmed progression. The current exploratory analysis was based on the latest available data from each trial (median time on study: RESONATE, 19 months; HELIOS, 17 months) using investigator assessments, but excluding del17p pts from RESONATE. Analyses were performed using data from both the overall CLL/SLL population and only the CLL pts. Separate multivariate Cox proportional hazards models were constructed for PFS and OS, including treatment and clinically relevant prognostic variables as covariates (age, gender, Rai staging, ECOG score, del11q status, refractory status, number of prior lines of therapy, bulky disease, IgVH status). Adjusted HRs and 95% CIs are presented vs single-agent ibr, along with predicted survival curves derived from the multivariate Cox regressions. Results RESONATE and HELIOS enrolled populations with notable differences making naïve comparison flawed. Because HELIOS enrolled only CIT-eligible pts, the trial included younger pts who had received fewer lines of therapy, as well as lower proportions of pts with purine analog refractory disease, del11q, or Rai stage 4 disease. These factors have been previously reported to influence outcomes in pts with R/R CLL/SLL and thus were included as covariates in the statistical models. Other baseline factors (gender, ECOG score, bulky disease, and IgVH status) were not notably different between the trials, but were found to impact PFS and OS and thus were included as additional covariates. In the overall CLL/SLL population, PFS and OS were comparable for single-agent ibr vs ibr + BR, and were significantly improved for single-agent ibr vs BR (Figure 1). Results for only the CLL pts were similar to those shown in Figure 1 for both PFS (ibr + BR vs single-agent ibr: 1.03 [0.61-1.75], p = 0.9042; BR vs single-agent ibr: 7.52 [4.72-11.99], p < 0.0001; single-agent ibr reduced the risk of progression/death by 87% vs BR) and OS (ibr + BR vs single-agent ibr: 1.20 [0.59-2.43], p = 0.6197; BR vs single-agent ibr: 2.24 [1.14-4.40], p = 0.0197; single-agent ibr reduced the risk of death by 55% vs BR). Conclusions The adjusted indirect comparisons reported here suggest superiority of single-agent ibr over BR for PFS and OS in patients with R/R CLL/SLL. The comparisons also suggest that the addition of BR to ibr did not improve PFS or OS compared with single-agent ibr. However, as median PFS has not been reached for either ibr arm, it is too early to draw firm conclusions. Longer follow-up in the ibr arms of these studies will be required to give an indication of whether CIT adds any benefit to ibrutinib for PFS and OS. Overall, these findings provide support for single-agent ibr as an appropriate choice for all pts with previously treated CLL/SLL. Disclosures Hillmen: Roche Pharmaceuticals: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; Celgene: Research Funding; Pharmacyclics LLC, an AbbVie Company: Honoraria, Research Funding. Fraser:Janssen: Honoraria, Research Funding, Speakers Bureau; Hoffman LaRoche: Consultancy, Honoraria; Celgene: Honoraria, Research Funding. Jones:Acerta Pharma BV: Research Funding. Rule:Roche: Consultancy, Other: Travel reimbursement; J&J: Consultancy, Other: Travel reimbursement, Research Funding; Celgene: Consultancy, Other: Travel reimbursement; Gilead: Research Funding. Dilhuydy:Roche: Honoraria, Other: Travel reimbursement; Janssen: Honoraria, Other: Travel reimbursement; Mundipharma: Honoraria. Jaeger:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Cymbalista:Karyopharm: Honoraria; Roche: Honoraria; Gilead: Honoraria; Janssen: Honoraria, Research Funding. Sun:Janssen/J&J: Employment, Equity Ownership. Ninomoto:Pharmacyclics LLC, an AbbVie Company: Employment. Mahler:Janssen: Employment, Other: Travel reimbursement. Cheng:Pharmacyclics LLC, an AbbVie Company: Employment. Diels:Janssen: Employment. Clow:Pharmacyclics LLC, an AbbVie Company: Employment. Salman:Janssen/J&J: Employment, Equity Ownership. James:Pharmacyclics LLC, an AbbVie Company: Employment. Howes:Janssen/J&J: Employment, Equity Ownership.

Introduction: Ibrutinib, a first-in-class, once-daily, oral covalent inhibitor of Bruton’s tyrosine kinase is highly effective in relapsed or refractory mantle cell lymphoma (MCL) patients with an ORR of 68% (Wang M, et al. N Engl J Med. 2013;369:507-516). Similar efficacy results were observed in a recent phase 2 study in MCL patients who progressed after rituximab containing chemotherapy and bortezomib therapy (SPARK study, NCT01599949). However, despite the very promising efficacy data, some patients with MCL do not respond to ibrutinib. Here, we report analyses of potential mechanisms associated with primary resistance to ibrutinib therapy in the SPARK study. Methods: In this phase 2, international, multicenter, single-arm study, patients with MCL received 560 mg/day oral ibrutinib continuously until progressive disease (PD) or unacceptable toxicity. Patients who had PD at the first disease evaluation were considered to have primary resistant disease. DNA was extracted from baseline/pretreatment tumor samples (biopsy or CD19-enriched cells from PBMC) and enriched libraries were constructed with probesets specific for the coding region of 97 genes possibly involved in ibrutinib response and resistance, using the Ovation Target Enrichment system (NUGEN). Deep sequencing (150bp, single end reads) was performed on an Illumina HiSeq instrument . Sequences were aligned to the hg19 reference genome, variants were called using samtools and filters were applied to identify possible somatic mutations (minor allele frequency < 1% in dbSNP, > 5% and < 95% variant allele, > = 10 total reads). Results: Twenty five (22.7%) of the 120 patients enrolled in this study had Independent Review Committee (IRC)-confirmed disease progression. In these primary treatment resistant patients, the median number of prior lines of systemic therapy was 3 (range 1-5 lines); 37% of patients had high risk MIPI score; 64% had bulky disease (longest diameter ≥ 5 cm), 52% had extranodal disease; 32% had bone marrow involvement and 20% had blastoid subtype. None of these baseline clinical parameters were found to be predictive for primary treatment resistance. The median duration of treatment was 1.54 months. Sequence data could be collected from 23 of the 25 patients, with an average of 9 million reads. After data filtering as described above, 27 genes were found with nonsynonymous variants in at least 2 or more patients. The majority of these variants were previously unreported in dbSNP or COSMIC databases. No mutations previously described in chronic lymphocytic leukemia (CLL) patients with acquired resistance to ibrutinib (BTK C481S, PLCg2 R665W) were seen in these patients, although one patient had a different mutation in PLCg2. Genes previously implicated in diffuse large B-cell lymphoma (DLBCL) pathogenesis (Pasqualucci L, et al. Nature Genetics. 2011;43:830-837) such as MLL2 and CREBBP were also found to be mutated in these patients. In addition, mutations in PIM1 and ERBB4 kinase genes were more frequent in patients with PD compared with those non-resistant to therapy. PIM1 kinase has been associated with increased proliferation, survival, and migration of tumor cells, and somatic mutations in this gene have been described in several cancers including hematologic malignancies. Interestingly, several of the mutations detected affect NF-kB signalling inhibition which is thought to contribute to ibrutinib’s mechanism of action. These results will be updated at the time of final presentation. Conclusion: Sequence analyses were conducted on tumor DNA from the fraction of patients with primary resistance to ibrutinib treatment in this study. These studies have revealed a number of known and novel mutations, including genes involved in NF-kB signalling. Among others, the mutational status of PIM1 kinase and ERBB4 kinase genes may be of interest with respect to primary resistance to ibrutinib therapy in MCL. Disclosures Balasubramanian: Janssen R&D: Employment, Equity Ownership. Schaffer:Janssen: Employment. Deraedt:Johnson & Johnson: Employment, Equity Ownership. Davis:Janssen: Employment. Aquino:Janssen R&D: Employment. Yuan:Johnson & Johnson : Employment, Equity Ownership. Kranenburg:Janssen Biologics: Employment; Johnson & Johnson: Equity Ownership. Dreyling:Janssen, Pfizer (support of IITs (institutional): Research Funding; Janssen, Pfizer (speaker's honoraria): Honoraria. Rule:Pharmacyclics, J&J: Consultancy, Membership on an entity's Board of Directors or advisory committees. Wang:Pharmacyclics, Janssen, Celgene, Onyx, OnyPep, : Research Funding; Onyx, Janssen: Honoraria. Zhuang:Johnson & Johnson: Employment, Equity Ownership. Rizo:Janssen R&D: Employment, Equity Ownership. Lenz:Janssen: Membership on an entity's Board of Directors or advisory committees.

Introduction Bruton’s tyrosine kinase (BTK) is a critical kinase involved in B-cell receptor signal transduction. ONO-4059, a highly potent and selective oral BTK inhibitor has demonstrated anti-tumour activity in pre-clinical models (Yasuhiro et al, AACR2013) and in the clinic in both CLL and NHL patients (Morschhauser et al, EHA 2014; Rule et al, EHA 2014). Here, we present data from 25 CLL patients enrolled in the ongoing Phase I study ONO-4059POE001. Methods Twenty five CLL patients were administered ONO-4059 as monotherapy, given once daily (QD) to determine safety, pharmacokinetics and pharmacodynamics, and preliminary efficacy. Patients can receive ONO-4059 for up to a maximum of 3 years and upon completion of the first 6 months of treatment, intra-patient dose escalation is permitted. Here, we present data for 25 evaluable patients treated with ONO-4059 at doses ranging from 20-600mg (8 cohorts). Patients had a median age 67 yrs [range 40-79], median baseline tumour burden 3,943 mm2 [461-19,750 mm2], median of 4 prior therapies [2-8], including fludarabine (23/25) and rituximab-containing therapy (23/25). Baseline median haematology parameters included lymphocytes 34.6 x 109/L [0.1-391], haemoglobins 11.1 g/dL [8.5-15.2], platelets 97 x 109/L [23-185], neutrophils 2.39 x 109/L [0.5-11.1]. 9/24 patients were 17p deleted [38%] and 6/24 had the 11q deletion [25%], 20/24 were IgVH unmutated status [83%], with 13/24 [54%] displaying TP53 mutation). Results To date, 19 of 25 patients remain on treatment with a median duration of treatment of 363 days [27-659]. ONO-4059 was found to be well tolerated with few adverse reactions over a long duration. A total of sixty two ONO-4059-related Grade 1- 2 adverse events were reported in 19 out of 25 patients. Eight dose independent ONO-4059-related G3 or G4 haematological toxicities were reported in 5 patients; with neutropenia in 3 patients, [G3 x 1, G4 x 2]), febrile neutropenia in 1 patient [G3] and leucopenia in 2 patients [G3 x 4]. Six Grade 3 ONO-4059-related non-haematological events were reported (pyrexia x 1, Hepatitis E reactivation x 1, Lymphocytic infiltration, Purpura, Urinary tract infection and Haematoma in just one patient). Nine ONO-4059-related SAEs were reported in 6 patients (febrile neutropenia [G3] and pyrexia [G3] at 20 mg, rash [G2] at 80 mg, hepatitis E reactivation [G3] at 320mg, neutropenia [G4] at 320 mg, purpura x 2 [G2, G3] and lymphocytic infiltration [G3] at 400 mg, haematoma [G2] at 500mg). All patients experienced rapid reductions in lymphadenopathy observed early in treatment between Cycle1 and Cycle3, accompanied by an increase in absolute lymphocyte count in 72% of patients. Almost all patients have durable response over a long duration. Best overall response rate according to IWCLL criteria (including modified PR with lymphocytosis) was 84% [based on CT-scan and P/E for 21/25 evaluable patients with 17 PR, 4 PR with lymphocytosis (for 21 responding patients, median reduction of lymph nodes was 83% [51-100]), 1 SD and 2 PD], with 89% response rate on 17p deleted. The early tumour shrinkage was associated with a rise in haemoglobin and platelet count. An increase in exposure (as assessed by Cmax and AUC) that was proportional to an increase in dose was seen for all doses of ONO-4059 ranging from 20-600mg. Conclusion ONO-4059 is a highly potent and selective oral Btk inhibitor with a favourable safety profile along with promising efficacy over a long duration in this heavily pre-treated population, with responses observed in relapsed, refractory and currently poor prognostic 17p deleted patients. Disclosures Fegan: ONO PHARMA: Honoraria. Salles:celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; genetech: Honoraria, Membership on an entity's Board of Directors or advisory committees. Karlin:Janssen: Honoraria; celgene: Consultancy, Honoraria; Sandoz: Consultancy. Rule:Pharmacyclics, J&J: Consultancy, Membership on an entity's Board of Directors or advisory committees. Morschhauser:ONO PHARMA: Honoraria; Roche: Honoraria; Celgene: Honoraria; Mundipharma: Honoraria. Dyer:ONO PHARMA: Research Funding. Cartron:ONO PHARMA: Honoraria. Honda:Ono Pharmaceutical Co., Ltd.: Employment. Yasuhiro:Ono Pharmaceutical Co., Ltd.: Employment. Yoshizawa:Ono Pharmaceutical Co., Ltd.: Employment.

Introduction: Despite recent advances, mantle cell lymphoma (MCL) remains difficult to treat with frequent chemoresistance in the relapsed or refractory setting. Ibrutinib, a first-in-class, once-daily, oral covalent inhibitor of Bruton’s tyrosine kinase, demonstrated durable single-agent efficacy in a previous phase 2 study of patients with MCL who had received 1 to 5 prior therapies (Wang M, et al. N Engl J Med. 2013;369:507-516). In that study, the investigator-assessed overall response rate was 68% (complete response rate, 21%). The current study reports on the efficacy and safety of single-agent ibrutinib specifically in patients with MCL who had received a rituximab-containing regimen and had progressed after at least 2 cycles of bortezomib therapy. Methods: In this phase 2, multicenter, single-arm study, patients received 560 mg/day oral ibrutinib continuously until progressive disease or unacceptable toxicity. The primary end point was the overall response rate (ORR) in response evaluable patients, as assessed by an Independent Review Committee (IRC). Secondary end points, also assessed by IRC, included duration of response (DoR), progression-free survival (PFS), overall survival (OS), and safety. Results: 120 patients in this international multicenter study were enrolled. The median age was 67.5 years, ranging from 35 to 85 years with 62.5% ≥ 65 years. Most patients had stage IV disease at study entry (77.5%), and 9.2% were reported as blastoid variant (per investigator). 76.3% of patients had an intermediate or high risk simplified MIPI score, and 52.5% had bulky disease (longest diameter ≥ 5 cm). Forty two (35.0%), 67 (55.8%) and 11 patients (9.2%) had an ECOG score of 0, 1 and 2, respectively. The median number of prior lines of systemic therapy was 2 (range 1-8 lines) with almost half of the patients (47.5%) receiving 3 or more prior lines of therapy. Overall, 33% of patients had received prior stem cell transplantation. At the time of clinical cut-off for the primary analysis (29 April, 2014), median follow-up was 14.9 months with median treatment duration of 8 months (range: 0.5-20.9 months). The main reasons for treatment discontinuation were disease progression in 53 patients (44.2%) and an adverse event (AE) in 8 patients (6.7%). The ORR for response evaluable patients was 62.7% (95% confidence interval [CI]: 53.7%-71.8%) with a complete response rate of 20.9%. Subgroup analysis suggested that the ORR was independent of age, gender, geographic region, number of prior lines of therapies, baseline extranodal disease, simplified MIPI score, bulky disease, and stage of MCL. Median DoR by IRC was 14.9 months and the median time to first response was 2.1 months, ranging from 1.3 to 6.3 months. Median PFS was 10.5 months and 47% of the patients remained progression-free at 1 year. The OS rate at 18 months was 61%. The most common AEs were fatigue (any grade, 43.3%; grade 3 or 4, 3.3%) and diarrhea (any grade, 42.5%; grade 3 or 4, 2.5%). The most common grade 3 or higher AEs were neutropenia (20.8%), thrombocytopenia (13.3%), and pneumonia (12.5%). Any-grade hemorrhagic events were reported in 45 patients (37.5%), including 3 (2.5%) with major hemorrhagic events. The median time to initial hemorrhagic event was 84 days (range 1-515 days), with a median duration of 22 days (95% CI: 8-31 days). Atrial fibrillation was reported in 13 patients (10.8%), which was grade 3 or 4 in 6 patients (5%). AEs led to dose reductions in 8 patients (6.7%). Conclusion: Single agent ibrutinib is highly efficacious and well tolerated, with an acceptable toxicity profile in patients with MCL who progressed after rituximab-containing chemotherapy and bortezomib therapy. These results are consistent with previous ibrutinib studies, with no new safety signals. Disclosures Wang: Pharmacyclics, Janssen, Celgene, Onyx, OnyPep, : Research Funding; Onyx, Janssen: Honoraria. Goy:Janssen/Pharmacyclics: Honoraria, Speakers Bureau; Clinical Trials through Institution: Research Funding; Janssen/Pharmacyclics: Membership on an entity's Board of Directors or advisory committees. Martin:Janssen: Honoraria. Popat:Janssen: Honoraria. Advani:Seattle Genetics, Genetech, (Uncompensated): Membership on an entity's Board of Directors or advisory committees; Janssen, Pharmacyclics, Seattle Genetics: Research Funding. Le Gouill:Roche: Consultancy; Janssen: Consultancy. Yuan:Johnson & Johnson: Equity Ownership; Johnson & Johnson: Employment. Kranenburg:Johnson&Johnson: Equity Ownership; Janssen Biologics: Employment. Rizo:Janssen R&D: Employment, Equity Ownership. Zhuang:Johnson & Johnson: Employment, Equity Ownership. Deraedt:Johnson & Johnson: Employment, Equity Ownership. Rule:Pharmacyclics, J&J: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Obinutuzumab (GA101; G) is an anti-CD20 monoclonal antibody with activity in relapsed/refractory follicular lymphoma (FL) as a single agent and in combination with chemotherapy. G-chemotherapy induction followed by G-maintenance has not been evaluated for untreated FL. The open-label, randomized, phase Ib GAUDI study (NCT00825149) investigated safety and efficacy of G + CHOP (G-CHOP) or bendamustine (G-B) as first-line treatment for FL. We report data from patients (pts) who received G-maintenance after responding to G-chemotherapy induction. Pts with treatment-naïve CD20+ B-cell FL and ≥1 bi-dimensionally measurable lesion (CT scan; largest dimension >1.5cm) were allocated on a per-center basis to receive induction G IV 1000mg + standard CHOP (3-weekly, 6–8 cycles) or B IV 90mg/m2(4-weekly, 4–6 cycles). Induction responders received G-maintenance every 3 months for 2 years or until disease progression (PD). Pts completing maintenance were followed for a further 2 years, until PD or start of new anti-lymphoma therapy. Anti-infective prophylaxis was used at investigator discretion. The primary objective was safety. Secondary objectives included progression-free survival (PFS) and response rates. The overall safety population comprised 81 pts (G-B: n=41; G-CHOP: n=40). Baseline characteristics (age, sex, FLIPI status, bone marrow involvement, bulky disease [lesion ≥7cm], time from diagnosis) were balanced between arms. Median observation time from study start was 31 months (G-B) and 33 months (G-CHOP). The maintenance safety population comprised 72 pts (n=36 from each induction therapy arm). Most pts completed maintenance (G-B: 81%; G-CHOP: 72%). There were 17 discontinuations (24%; G-B: n=7; G-CHOP: n=10), due to an adverse event (AE)/intercurrent illness (n=9), insufficient therapeutic response (n=5), administrative/other (n=2) and death (n=1). During 2 years’ maintenance most pts had AEs: G-B, 100% (44% grade ≥3); G-CHOP, 78% (31% grade ≥3). The most common AE (all grades) was cough (G-B: 17%; G-CHOP: 11%). The grade ≥3 AEs mainly reflected infections and cytopenia. Six G-B pts (17%) experienced 7 grade ≥3 infections; 4 were considered treatment related (genital infection, oral herpes, pneumonia klebsiella, neutropenic infection). Five G-CHOP pts (14%) had one grade ≥3 infection each; 4 were considered treatment related (viral meningitis, respiratory tract infection [RTI], bacterial pneumonia [2 events]). Six G-B pts (17%) experienced 10 grade ≥3 cytopenia AEs; 7 were considered treatment related (anemia, febrile neutropenia, pancytopenia, neutropenia [2 events], thrombocytopenia [2 events]). No G-CHOP pt experienced a grade ≥3 cytopenia AE. AEs led to dose delays in 17% (G-B) and 6% (G-CHOP) of pts. Three pts (G-B: n=1; G-CHOP: n=2) had treatment-related AEs during, or within 24 hours of, an infusion (all grade 1–2). Two deaths (both G-CHOP) occurred during maintenance or maintenance follow-up; 1 due to PD and 1 due to a G-related AE (RTI leading to fatal lactic acidosis). At the end of maintenance, all pts with data available (G-B: n=41; G-CHOP: n=39) had experienced B-cell depletion (0.07x109cells/L). Median IgG levels remained within normal range during maintenance. In the overall safety population, complete response (CR) rate (based on CT scan rather than PET) as best overall response increased from end of induction (G-B: 37%; G-CHOP: 35%) to end of maintenance (G-B: 61%; G-CHOP: 70%). PFS rate at 32 months after first study drug was 92% (G-B) and 84% (G-CHOP). Median PFS was not reached; 10 pts (G-B: n=4; G-CHOP: n=6) had PD, including one transformation to diffuse large B-cell lymphoma. G-maintenance after G-chemotherapy induction was associated with a high CR rate in pts with previously untreated FL. Opportunistic infections occurred infrequently. Clinically relevant neutropenia was experienced by 14% of pts who received G-B induction but was not observed in G-CHOP pts. A phase III trial (GALLIUM) is investigating G versus rituximab in chemoimmunotherapy induction followed by immunotherapy maintenance in pts with untreated indolent non-Hodgkin lymphoma. Disclosures Off Label Use: Obinutuzumab is a type II CD20 monoclonal antibody which is licensed for use in combination with chlorambucil in untreated patients with CLL but is not currently approved for use in follicular lymphoma.. Grigg:Roche: Consultancy. Dreyling:Roche: Honoraria, Research Funding. Rule:Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees. Lei:Roche Products Ltd.: Employment. Wassner-Fritsch:Roche: Employment. Fingerle-Rowson:F. Hoffmann–La Roche: Employment. Marlton:Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Introduction R-CHOP is the standard of care for patients with diffuse large B cell lymphoma (DLBCL) however poor risk patients (IPI 3-5) still have an inadequate outcome. Neither first remission high dose chemotherapy and peripheral blood stem cell transplantation (HDC+PBSCT) nor selection of cases for intensification by interim PET scanning have demonstrated a proven benefit. In the case of Burkitts lymphoma (BL) there is a paucity of data on the addition of Rituximab to the CODOX-M and IVAC regimen. Patients and Methods 113 patients with DLBCL and 37 with BL were recruited from 53 UK sites between May 2008 and April 2013. Median age was 49 years (18-65). For DLBCL patients IPI scores were 3 – 72 ( 64%), 4 -40 (35%) and 5 – 1 (1%). All patients received the modified CODOX-M and IVAC regimen including all CNS directed therapy( Mead et al Ann Oncol. 2002 Aug;13(8):1264-74) and 8 doses of rituximab. The primary end point of the study was Progression Free survival (PFS) and secondary endpoints included toxicity and CR rate. Results The main toxicities reported were neutropenia ( 89% grade 3 or 4), thrombocytopenia (84.2% grade 3 or 4), infection 61.6% grade 3 or 4 and mucositis (30.1% grade 3 or 4). 4 patients were excluded from toxicity assessment as they did not start therapy after registration. There were 8 treatment related deaths observed (infection with neutropenia (5), GI haemorrhage (1), acute cerebral haemorrhage (1) and bowel perforation (1) ). 78 patients with DLBCL and 31 with BL have completed all therapy ( 78.5 % of patients with available data) with an overall response rate of 92 % for DLBCl and 94% for BL. In patients who completed all therapy CR was achieved in 34 (44%), CR (u) in 8 (10%) and PR in 30 (38%) for DLBCL patients and CR was achieved in 21 (68%), CR (u) in 6 (19%) and PR in 2 (6%) in BL patients. 3 patients ( 2 DLBCL and 1 BL) who progressed during therapy have been included in the response analysis. End of treatment PET scanning was not obligatory. 80 patients with DLBCL and 30 patients with BL remain alive and without progression at a median follow up of 18.6 and 19.3 months respectively. Conclusion The R-CODOX-M -R-IVAC regimen can be delivered to patients with poor risk DLBCL in a multicentre setting. High rates of haematological toxicity and consequent infection are inevitable with treatment of this intensity but appear acceptable when compared with other treatments such as HDC+PBSCT. Response rates are encouraging in view of the very poor risk IPI profile of the patients included in this study. Burkitts lymphoma patients also achieved an excellent response rate with no apparent additional toxicity attributable to the addition of rituximab to the regimen. We currently plan the first analysis for the primary endpoint of PFS in 2015. The Trial was supported by Leukaemia and Lymphoma Research (LLR). Disclosures: McMillan: Roche: Consultancy, Honoraria; Amgen: Research Funding. Off Label Use: Rituximab usage in Burkitts Lymphoma. Ardeshna:Roche: Honoraria, Research Funding. Jack:Roche/Genentech: Research Funding. Patmore:Roche: Consultancy, Honoraria. Pettengell:Roche: Honoraria; Amgen: Honoraria. Linch:Roche: Honoraria, Research Funding.

Background Rituximab is part of the standard induction and maintenance therapy for most patients with first-line or relapsing indolent non-Hodgkin's lymphoma (iNHL). However, the optimal duration of maintenance is still to be defined. The MABCUTE trial is designed to evaluate the efficacy and safety of maintenance therapy with subcutaneous (SC) rituximab until disease progression (PD). Patients with relapsed or refractory iNHL, who respond to induction and an initial 2 years' maintenance therapy, are randomized to receive additional maintenance therapy or observation. Here we report the findings of a planned interim safety analysis in the first 231 patients enrolled in the trial. Methods MABCUTE (NCT01461928) is an ongoing multicenter, randomized, parallel-group, phase IIIb study that started in December 2011. Eligible patients were aged ≥18 years with relapsed or refractory CD20+ iNHL (histologically confirmed) following ≥1 line of immunotherapy and/or chemotherapy and/or radiotherapy. Patients were scheduled to receive induction therapy consisting of rituximab every 3–4 weeks for 8 cycles (intravenous [IV] 375 mg/m2 in cycle 1 then SC 1400 mg in cycles 2–8) and 6–8 cycles of standard chemotherapy. Patients who achieved a complete or partial response (CR/PR) continued into standard maintenance (rituximab SC 1400 mg every 8 weeks for 24 months). Upon completion of standard maintenance, patients in sustained CR/PR will be randomized to receive additional maintenance (rituximab SC 1400 mg every 8 weeks) until PD, or observation. Results At data cut-off (January 16, 2013), the safety population consisted of 216 patients who had received ≥1 dose of rituximab SC: 70 (32%) had completed induction therapy, 122 (57%) were receiving induction therapy, and 24 (11%) had discontinued induction therapy. A total of 58 (27%) patients had continued into standard maintenance, with 2 patients having subsequently discontinued maintenance therapy. Patients had a median age of 64.5 years (range, 20–90). At screening, the most common types of iNHL were follicular NHL (n=131, 61%), marginal zone lymphoma (n=41, 19%), and Waldenström's macroglobulinemia (n=31, 14%). The most commonly used chemotherapy regimens were bendamustine (n=137, 63%), CHOP (n=31, 14%) and CVP (n=21, 9.7%). During therapy, AEs occurred in 174 (81%) patients (Table), grade 3 or higher AEs in 70 (32%) patients and serious AEs (SAEs) in 44 (20%) patients. Administration-related reactions (ARRs) were reported by 61 (28%) patients after 1 dose of rituximab IV and by 89 (41%) patients after a median (range) of 5 (1–11) doses of rituximab SC. The majority of ARRs were mild to moderate and transient, and expected with the change in the route of administration. Overall, 25 patients had grade 4 hematological events, most commonly neutropenia (22 patients). Only 4 cases of neutropenia lasted >14 days and these resolved without interruption to treatment. One patient had a grade 4 non-hematological event (thrombosis and pulmonary embolism that resolved after 12 days). Among the 26 patients who discontinued study treatment, reasons given were AEs (n=8; skin reactions [3], neutropenia [2], general health problems [2], and oseophagitis [1]), patient or investigator request (n=6), PD (n=5), death (n=2), and other (n=5). One patient died of bronchopneumonia and sepsis due to leucopenia and 1 died of myocarditis; neither was considered by the investigator to be related to the study drug. Conclusions Rituximab SC is associated with ARRs that are transient and mainly mild to moderate in severity. The incidence and intensity of other hematological and non-hematological toxicities are within the expected range for rituximab SC or IV administration. No new safety signals or concerns associated with rituximab SC were identified during induction and maintenance therapy in this interim safety analysis, as confirmed by the Independent Data Monitoring Committee. Rituximab SC appears to be well tolerated and the study continues. Disclosures: Rule: Pharmacyclics, Inc: Consultancy; J&J: Consultancy; F. Hoffmann-La Roche: Consultancy. Off Label Use: Rituximab, administered as an IV infusion, is approved for use in a number of hematologic indications. The data presented here assess a subcutaneous approach to rituximab administration in patients with indolent Non-Hodgkin’s Lymphoma. Briones:Celgene: Membership on an entity’s Board of Directors or advisory committees; Takeda: Membership on an entity’s Board of Directors or advisory committees; Novartris: Membership on an entity’s Board of Directors or advisory committees; F. Hoffmann-La Roche: Honoraria. Casasnovas:F. Hoffmann-La Roche: Consultancy, Research Funding. Pocock:F. Hoffmann-La Roche: Honoraria. Osborne:F. Hoffmann-La Roche: Employment. Smith:F. Hoffmann-La Roche: Employment. Zaja:F. Hoffmann-La Roche: Consultancy.

Introduction The role of both autologous (autoSCT) and allogeneic stem cell transplantation (alloSCT) in the management of patients with mantle cell lymphoma (MCL) remains to be clarified. In the absence of prospective comparative trials decision making for clinicians remains challenging. We have conducted a consensus project to provide guidance on how stem cell transplantation should be employed in MCL. Methods This was a collaborative project between the Lymphoma Working Party of the EBMT and the European Mantle Cell Lymphoma Network. The RAND modified Delphi consensus procedure was used. 12 clinicians, recognized for their expertise in MCL, from both transplant and non-transplant centres contributed. A literature search was performed and consensus statements were formulated. Panel members ranked each statement. The statements were reviewed and modified and then a second round of ranking was performed. Results Consensus agreement was reached on the following statements: 1. Patients should be considered for transplant strategies based on their biological age and comorbidities and not just chronological age. 2. An autoSCT should be considered as the standard first line consolidation therapy in all patients considered suitable for high dose therapy. 3. First line induction therapy prior to SCT should incorporate high dose cytarabine and Rituximab based regimens. 4. Patients achieving either complete remission or partial remission following induction therapy should be considered for autoSCT. 5. Patients failing to achieve a PR or CR following induction therapy should not proceed directly to an autoSCT. 6. Patients undergoing an allogeneic SCT should receive reduced intensity conditioning regimens. There was consensus disagreeing with the following statement: Prognostic criteria are available that permit the identification of low risk patients in need of first line therapy who should be considered for non-transplant based treatment. There was partial consensus agreeing with the following statements: 1. Patients relapsing after an autoSCT should be considered for an allogeneic stem cell transplant following reinduction therapy.2. Patients with evidence of MRD relapse post alloSCT should, in the absence of graft versus host disease, be considered for rapid withdrawal of immunesuppression and donor lymphocyte infusions. There was a partial consensus disagreeing with the following statements: 1 Patients should receive Rituximab maintenance following first line autologous stem cell transplant. 2. There are sufficient prognostic criteria to identify patients who should undergo an allogeneic stem cell transplantation as first line consolidation. 3. In patients relapsing after non-transplant first line therapy there are sufficient prognostic criteria to determine whether autoSCT or alloSCT consolidation should be used. Finally there was no consensus with respect to the following statements. 1. Disease response to induction therapy prior to autoSCT should be assessed by PET scan. 2. Minimal residual disease (MRD) negativity is mandatory prior to autoSCT. 3. A TBI based regimen should be considered as the standard for conditioning prior to autoSCT. 4. Patients undergoing an autoSCT should receive in-vivo purging with Rituximab at the time of high dose conditioning therapy. 5. Patients with relapsed disease following non-transplant first line therapy should be considered for an autologous stem cell transplant to consolidate second (or higher) response. 6. Patients with relapsed disease following non-transplant first line therapy should be considered for an allogeneic SCT to consolidate second (or higher) response. 7. Patients undergoing autoSCT should be monitored for MRD post transplant. 8. Patients with evidence of MRD relapse post autoSCT should receive preemptive Rituximab. 9. Patients undergoing alloSCT should be monitored for MRD post transplant. Conclusions Consensus was obtained with regard to the role of autologous SCT in first line consolidation. However, the application of appropriate clinical and molecular prognostic factors to guide therapeutic decisions and the role of allogeneic transplantation warrant further clinical investigation. Disclosures: No relevant conflicts of interest to declare.

Introduction The B-cell receptor (BCR) pathway plays a central role in signal transduction pathways that regulate survival, activation, proliferation and differentiation of B-lineage lymphoid cells. Bruton’s tyrosine kinase (Btk) is a critical kinase in BCR signal transduction and recent studies support that targeting Btk is effective in the treatment of B-cell malignancies. ONO-4059 is a highly potent and selective oral Btk inhibitor with an IC50 in the sub-nmol/L range that has demonstrated anti-tumour activity in several pre-clinical models (Yasuhiro T et al, AACR 2013). Methods This Phase I study was initiated to determine the safety, tolerability, dose-limiting toxicity (DLT), pharmacokinetics and pharmacodynamics of ONO-4059 given as monotherapy to patients with relapsed/refractory NHL for whom no therapy of higher priority was available. In this safety-driven, dose-escalating 3+3 design, ONO-4059 was administered as an oral, daily dose (flat dose) given continuously initially for up to 6 months, with the option of additional dosing up to 2 years. We present the safety and efficacy data on 14 evaluable patients (mantle cell lymphoma n=7, follicular lymphoma n=3, plasmablastic DLBCL n=1, ABC-DLBCL n=1, small lymphocytic lymphoma n=1 and Waldenstrom’s macroglobulinaemia n=1), with a median age 64 yrs (range 48-88), median baseline tumour burden 5,668 mm2 [1,582-19,509]. Patients received a median of 3 prior therapies [range 2-8], with all patients having prior exposure to a rituximab-containing regimen 93% (13/14) and 29% of patients (4/14) had prior ASCT. Patients received ONO-4059 at doses ranging from 20mg-160mg (cohorts 1-4) and the study is currently ongoing with additional dose escalation cohorts to be completed. Results ONO-4059 was found to be well tolerated, with no dose limiting toxicities (DLTs). A total of 18 ONO-4059-related adverse events were reported in 6 out of 14 patients; CTCAE-V4.0 G1 (n=10 [n=6 in 1 patient]) and G2 (n=5). Three ONO-4059-related G3 haematological toxicities were reported in 2 patients; thrombocytopenia (x2) and anemia. No ONO-4059-related G4 events, or related SAEs or infections were reported. The pharmacokinetics of ONO-4059 reflects rapid absorption and elimination, a half-life of ∼6 hours, a dose dependent increase in exposure with no accumulation of ONO-4059 exposure and low inter- or intra-patient variability; with Btk occupancy in peripheral blood (as measured by phosphorylated Btk) being maintained for at least 24 hours across all dose levels. Responses have occurred at doses of 40, 80 and 160mg, with a best overall response rate of 42% [based on CT-scan and physical examination for 5/12 evaluable patients]; with 5 PR, 4 SD, 2 PD (both MCL) and one ABC-DLBCL patient was withdrawn due to non-related SAE during Cycle 1. Of the 6 evaluable MCL patients, 3 have achieved PR resulting in a best ORR of 50% (median reduction of lymph nodes was 73% [45%-84%]). Almost all patients experienced clinically meaningful rapid reductions in lymphadenopathy observed within the first cycle. Ten of the fourteen patients are currently still on study with a median progression-free survival of 93.5 days [Range 8-268]. In conclusion, ONO-4059 is a highly potent and selective oral Btk inhibitor that shows a favourable safety profile along with promising efficacy in this difficult-to-treat patient population. Disclosures: Salles: Janssen: Honoraria; Gilead: Honoraria; Celgene: Honoraria. Karlin:Janssen: Honoraria; Celgene: Honoraria. Morschhauser:ONO Pharma: Honoraria; Roche: Honoraria; Celgene: Honoraria; Mundipharma: Honoraria. Dyer:Ono Pharma: Honoraria, Research Funding. Hutchinson:Ono Pharma: Research Funding. Fegan:ONO Pharma: Honoraria. Cartron:ONO Pharma: Honoraria. Knurowski:ONO Pharma: Consultancy. Wright:ONO Pharma: Consultancy. Saunders:ONO Pharma: Consultancy; Pharmacyclics: Consultancy. Honda:ONO Pharma: Employment. Mazur:ONO Pharma: Consultancy. Yoshizawa:Ono Pharma: Employment. Kawabata:Ono Pharmaceutical Co., Ltd.: Employment. Birkett:Ono Pharma UK: Employment.

Abstract 904 Background Bruton's tyrosine kinase (BTK) is a central mediator of B-cell receptor (BCR) signaling which is essential for normal B-cell development. Ibrutinib is an orally administered inhibitor of BTK that induces apoptosis and inhibits cellular migration and adhesion in malignant B-cells. MCL is an aggressive subtype of NHL, and despite high response rates to initial therapy, patients often relapse with acquired chemotherapy resistance and short response durations to conventional therapy. Preliminary results in 51 evaluable patients from the Phase 2 PCYC-1104 study demonstrated ibrutinib could achieve rapid nodal responses (including complete responses) in relapsed and refractory MCL patients (Wang et al, ASH 2011). Treatment with ibrutinib was associated with a transient increase in peripheral lymphocyte count representing a compartmental shift of cells with the CD19+/CD5+ phenotype from nodal tissues to peripheral blood (Chang et al, ASH 2011). Reported here are interim results of an international study of single-agent ibrutinib in previously treated MCL. Methods Subjects with relapsed or refractory MCL who were either bortezomib-naïve or bortezomib-exposed (prior treatment with at least 2 cycles of bortezomib) were enrolled. Ibrutinib was administered orally at 560mg daily (in continuous 28-day cycles) until disease progression. Bortezomib-naive and bortezomib-exposed cohorts were evaluated separately. Tumor response was assessed every 2 cycles according to the revised International Working Group for NHL criteria. The primary endpoint of the study is overall response rate (ORR). Secondary endpoints include: duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety. Subjects A total of 115 subjects (65 bortezomib-naïve and 50 bortezomib-exposed) were enrolled between February 15, 2011 and July 3, 2012. Of the 111 subjects treated, 109 subjects were evaluable for efficacy (received at least one dose of ibrutinib and underwent ≥ 1 tumor response assessment). Baseline characteristics include median age 68 years (40–84), median time since diagnosis 42 months, median number of prior treatments 3 (1–6), bulky disease (≥ 10 cm) 13%, Ann Arbor stage IV at screening 77.4%, prior stem cell transplant 9.6%, high risk by MIPI score at baseline assessment 48.7%, and refractory disease 44.3%. Results Safety data are available for 111 subjects. Treatment-emergent AEs occurring in ≥ 15% of subjects: diarrhea (35%), fatigue (32%), upper respiratory tract infections (23%), nausea (21%), rash (21%), dyspnea (20%), and oedema peripheral (15%). Grade 3 or higher AEs occurring in ≥ 5% of subjects were neutropenia (11%), anemia (5%), diarrhea (5%), dyspnea (5%), pneumonia (5%), and thrombocytopenia (5%). Grade 4 treatment-related AEs were neutropenia (5%), hyperuricaemia (2%), and pancytopenia (1%). One grade 5 AE, pneumonia, was thought to be treatment-related. In the efficacy evaluable subjects, the ORR (complete + partial responses) is reported in Table 1. The median time on treatment was 6.0 months (0.7-16.6 months); 53% of subjects remain on treatment. Median DOR, PFS and OS have not been reached: 9 month DOR 65%, 12 month estimation of PFS 53% and OS 67%. Responses to ibrutinib increase with longer time on study treatment. Time to PR ranged from 1.4 – 8.3 months (median 1.9) and CR ranged from 1.7 – 11.2 months (median 3.9). This is seen with longer follow-up on the initial 51 subjects reported at ASH 2011: median time on study treatment was 3.8 months and is now 11.3 months; ORR was 69% and is now 74.5%; CR rate was 16% and is now 35.3%. Conclusions Longer follow up demonstrates the durability of responses and confirms the unprecedented single agent activity of ibrutinib in relapsed or refractory MCL in terms of ORR. The treatment- emergent AEs were consistent with safety data previously reported. A pivotal study in relapsed and refractory MCL patients following bortezomib treatment has been initiated. Disclosures: Wang: Pharmacyclic: Research Funding. Off Label Use: Ibrutinib is a novel agent being studied in a clinical trial. Rule:Pharmacyclics: Research Funding. Martin:Pharmacyclics: Research Funding. Goy:Pharmacyclics: Research Funding. Auer:Pharmacyclics: Research Funding. Kahl:Pharmacyclics: Research Funding. Jurczak:Pharmacyclics: Research Funding. Advani:Pharmacyclics: Research Funding. McGreivy:pharmacyclics: Employment, Equity Ownership. Clow:Pharmacyclics: Employment, Equity Ownership. Stevens-Brogan:Pharmacyclics: Employment, Equity Ownership. Kunkel:Pharmacyclics: Employment, Equity Ownership. Blum:Pharmacyclics: Research Funding.

Abstract 265 Background: Treatment goals in patients with relapsed FL are to prolong PFS and improve overall survival (OS). To optimize treatment for individual patients, identification of subgroups most likely to benefit from a specific therapy is important. The international, randomized, phase 3 LYM3001 study in patients with relapsed or refractory FL demonstrated improved PFS with bortezomib-rituximab vs rituximab alone (median 12.8 vs 11.0 months, HR 0.822, p=0.039), plus increased overall response rate (ORR; 63% vs 49%, p=0.0004), complete response rate (CR/CRu; 25% vs 18%, p=0.035), and durable (≥6 months) response rate (50% vs 38%, p=0.002) in an unselected patient population. Here we present exploratory biomarker analyses aimed at identifying patient subgroups deriving a longer PFS benefit with bortezomib-rituximab and showing a trend for better OS. Methods: Patients received five 5-week cycles of bortezomib-rituximab (N=336) or rituximab (N=340). Response was assessed using modified International Working Group response criteria. Archived tumor tissue was collected at baseline from 502 (74%) patients; whole blood samples for germ-line DNA were collected on day 1 of cycle 1 from 619 (92%) patients. Protocol-specified candidate biomarkers were based on associations with bortezomib (NF-κB p65, PSMA5, p27, PSMB1/5/8/9) or rituximab (CD68, FCGR2A/3A) activity. Immunohistochemistry assays were used for protein analysis. Taqman SNP assays and PCR/LDR were used for genotyping. Statistical analyses included single-marker analyses, pair-wise combination analyses (n=1140 comparisons), and multiple comparison analyses of all evaluable patients in LYM3001. Clinical covariates included in the analysis were baseline FLIPI score, prior rituximab, time since last anti-lymphoma therapy, region, age, gender, race, Ann Arbor stage, high tumor burden, and number of prior lines of therapy. Results: Single markers and biomarker pairs (n=102) highlighted patient subsets that had significantly improved outcomes with bortezomib-rituximab vs rituximab. For 14 of the pairs, the PFS benefit was ≥6 months. Using false discovery rate (FDR) to control for multiple comparison corrections, one biomarker pair was significant. This pair (presence of the PSMB1 P11A C/G heterozygote, and low CD68 expression [0–50 CD68-positive macrophages in the follicular space]) was associated with significantly improved PFS in patients receiving bortezomib-rituximab vs rituximab (median 16.6 vs 9.1 months, HR 0.407, p2 prior lines of therapy). There was also a trend towards an OS benefit (medians not reached, HR 0.426, p=0.0550), as well as a significantly higher ORR (73.7% vs 47.5%, p=0.0077), a higher CR rate (33.3% vs 23%, p=0.3044), and a significantly longer time to next therapy (median 33.1 vs 14.8 months, p=0.0013). In patients lacking this biomarker pair (N=238) no significant efficacy differences were seen. No other similar studies were available to confirm the reproducibility of these analyses. Therefore, we split the LYM3001 dataset into discovery and confirmation cohorts (7:3 ratio of biomarker-evaluable patients) to enable evaluation and confirmation in independent cohorts of patients The significant biomarker pair of PSMB1 P11A C/G heterozygote and low CD68 was identified in the discovery cohort (N=198) with a PFS advantage with bortezomib-rituximab vs rituximab of 5.7 months (median 14.2 vs 8.4 months, p=0.0003) and an indication of longer OS (HR 0.47, p=0.1291). This biomarker pair also showed a clear PFS advantage in the confirmation cohort (N=108, 8.7-month PFS benefit; median 18.2 vs 9.5 months, HR 0.44, p=0.0817). Other significant biomarker combinations, including combinations of molecular and clinical variables (e.g. high tumor burden) were identified and will be presented. Conclusions: Analyses of the phase 3 LYM3001 trial identified biomarker combinations present in a third of patients offering a significant PFS benefit with bortezomib-rituximab vs rituximab. Use of such biomarker assays in patients with relapsed or refractory FL may aid identification of subgroups deriving maximal benefit from the addition of bortezomib to rituximab therapy. Disclosures: Coiffier: Janssen-Cilag: Consultancy; Roche: Consultancy; Amgen: Consultancy; Sanofi: Consultancy; Pfizer: Consultancy; Millennium Pharmaceuticals, Inc.: Consultancy; Celgene: Consultancy; Pharmacyclics: Consultancy; MedImmune: Consultancy; CTI: Consultancy. Off Label Use: Bortezomib used in combination with rituximab in patients with relapsed/refractory follicular lymphoma. Li:Janssen Research & Development: Employment; Johnson & Johnson: Equity Ownership. Henitz:Janssen Research & Development: Employment. Karkera:Janssen Research & Development: Employment; Johnson & Johnson: Equity Ownership. Favis:Janssen Research & Development: Employment; Johnson & Johnson: Equity Ownership. Gaffney:Janssen Research & Development: Employment; Johnson & Johnson: Equity Ownership. Shapiro:Janssen Research & Development: Employment; Johnson & Johnson: Equity Ownership. Theocharous:Janssen Research & Development: Employment; Johnson & Johnson: Equity Ownership. Elsayed:Janssen Research & Development: Employment; Johson & Johnson: Equity Ownership. de Velde:Janssen Research & Development: Employment; Johnson & Johnson: Equity Ownership. Rule:Johnson & Johnson: Advisory Board, Institutional grant, meeting attendance expenses, Honoraria. Walewski:Janssen-Cilag: Institutional/personal grants, advisory board; Hoffman La Roche: Honoraria, Institutional/personal grants, travel/accommodation expenses; Mundipharma: Honoraria; Celgene: Honoraria. de Vos:Millennium Pharmaceuticals, Inc: Consultancy. Crump:Janssen/Ortho-Biotech: Consultancy. Shpilberg:Janssen-Cilag: Consultancy, Honoraria. Cakana:Janssen Research & Development: Employment; Johnson & Johnson: Equity Ownership. Esseltine:Millennium Pharmaceuticals, Inc: Employment; Johnson & Johnson: Equity Ownership. Mulligan:Millennium Pharmaceuticals, Inc.: Employment. Ricci:Janssen Research & Development: Employment; Johnson & Johnson: Equity Ownership.

Abstract 442 Introduction: Bruton's tyrosine kinase (Btk) is a central mediator of B-cell receptor signaling which is essential for normal B-cell development. PCI-32765 is an orally administered irreversible inhibitor of Btk that induces apoptosis and inhibits cellular migration and adhesion in malignant B-cells. In a phase I trial of PCI-32765 in relapsed B-cell malignancies, objective responses were observed in seven of nine patients with MCL. Reported here are preliminary results of an ongoing phase II study of single-agent PCI-32765 in previously treated MCL. Methods and Patients: Patients with relapsed or refractory MCL who were either bortezomib-naïve or bortezomib-exposed (prior treatment with at least 2 cycles of bortezomib) were eligible for study PCYC-1104. PCI-32765 was administered orally at 560mg daily (in continuous 28-day cycles) until disease progression. Bortezomib-naive and bortezomib-exposed cohorts were evaluated separately. Tumor response was evaluated every 2 cycles and classified by 2007 NHL IWG criteria. Results: A total of 48 patients (29 bortezomib-naive, 19 bortezomib-exposed) have been enrolled on study PCYC-1104 between February 16, 2011 and July 20, 2011. The median age is 67 years (62–72). The median number of prior treatment regimens is 2 (1–5). Five patients (13%) had received prior autologous or allogeneic stem cell transplantation. Seven patients (15%) had bulky disease. Thirty-nine patients who have initiated treatment and have reported adverse event (AE) information are the subject of this preliminary report. Twenty-four patients (12 bortezomib-naive, 12 bortezomib-exposed) have undergone at least 1 follow-up tumor assessment and are evaluable for efficacy. Treatment has been well tolerated. No patients have discontinued treatment due to AEs. Grade 1 or 2 diarrhea, fatigue, and nausea have been the most frequently reported AEs. Grade >3 AEs considered potentially related to PCI-32765 have occurred in 4/39 patients (11%). Serious AEs (SAEs) have occurred in 8/39 patients (21%); 2 SAEs (1 rash, 1 febrile neutropenia) were considered potentially related to PCI-32765. One death, in a patient who was enrolled but did not receive PCI-32765 due to rapid disease progression, has occurred on study. The objective response rate (ORR) by IWG criteria is 67% (16/24); ORR is 58% (7/12) in the bortezomib-naive cohort and 75% (9/12) in the bortezomib-exposed cohort. To date, 35/39 patients remain on PCI-32765; reasons for discontinuation include progressive disease (n=3) and investigator decision (n=1). Conclusions: Preliminary data from a phase II trial suggests that the potent Btk inhibitor PCI-32765 is well tolerated and induces a high rate of objective responses in patients with relapsed or refractory MCL. More mature safety and efficacy data will be updated in the presentation. Phase III trials of PCI-32765 in MCL are planned. Disclosures: Wang: Pharmacyclics: Research Funding. Off Label Use: PCI-32765 in mantle cell lymphoma in a phase 2 clinical trial. Martin:Pharmacyclics: Research Funding. Blum:Pharmacyclics: Research Funding. Kahl:Pharmacyclics: Research Funding. Maeda:Pharmacyclics: Research Funding. Advani:Pharmacyclics: Research Funding. Williams:Pharmacyclics: Research Funding. Rule:Pharmacyclics: Research Funding. Rodriguez:Pharmacyclics: Employment, Equity Ownership. Pang:Pharmacyclics: Consultancy. Hedrick:Pharmacyclics: Employment, Equity Ownership. Goy:Pharmacyclics: Research Funding.

Abstract 440 Background: Rituximab is widely used in combination with chemotherapy for treating B cell lympho-proliferative disorders. In MCL, two randomised trials explored the addition of Rituximab to standard initial therapy. Neither demonstrated a significant improvement in either PFS or OS. In 2002 the NCRN initiated a phase II randomised trial of FC chemotherapy with or without Rituximab to evaluate response rates. In 2006 this was extended to a phase III study with overall survival as the primary end point. Trial: Newly diagnosed patients with MCL requiring therapy received up to 8 cycles of oral FC (Fludarabine 40mg/m2 and Cyclophosphamide 250mg/m2 both daily × 3) given every 4 weeks with a randomisation to the addition of Rituximab 375mg/m2 on day 1. There was no age limit to the study, no risk stratification and no consolidation of responses with transplantation or maintenance therapy. Results: 370 patients were randomised. Median age was 66 years (range 36 – 88) with 76% male patients. The arms were well balanced by Mantle Cell International Prognostic Index (MIPI); 77% in the FCR arm and 71% in the FC arm were in the intermediate or high risk groups. 78% and 72% respectively received 4 or more cycles of FCR/FC. At the end of treatment the ORR was 90.6% in the FCR arm and 79.8% in the FC arm (p = 0.01) with CR + CRu rates of 64.7% and 46.9% (p = 0.002) respectively. 5.8% of patients in the FCR arm and 11.9% in the FC arm had PD at the end of treatment. Patients in the FCR arm had longer progression free and overall survival with HRs of 0.56 (95% CI: 0.43–0.73, p < 0.001) and 0.72 (95% CI: 0.54–0.97, p = 0.03) respectively. At a median follow up of 38.8 months the median PFS is 30.6 months in the FCR arm and 16.1 months in the FC arm. The median OS is 45.7 months for FCR and 37 months for FC. The major toxicities were haematological. Significantly more patients in the FCR arm experienced grade 3 or 4 Leucopoenia and Thrombocytopenia however the numbers of grade 4 were not significantly different. Combined grade III/IV toxicity showed 23.3% thrombocytopenia, 45.8% leucopoenia, 12.9% anaemia and 51.4% neutropenia. 11.8% of patients had significant infections. Renal toxicity was modest. 1 patient experienced grade III but there was no grade IV toxicity. Lymphoma was the commonest cause of death, but 29% of patients in the FCR arm and 24% in the FC arm died of other causes, of which almost half were infection related. An additional 11 patients died of a second malignancy, 4 of whom had AML. 14% of patients in the FCR arm and 10% in the FC arm died without evidence of disease progression. Conclusion: The addition of Rituximab to FC chemotherapy leads to a significant improvement in both PFS and OS with an acceptable level of additional toxicity. A significant number of patients treated with FC based chemotherapy die whilst in remission of non lymphoma related causes. Disclosures: Rule: Roche: Consultancy, Research Funding. Off Label Use: Rituximab in mantle cell lymphoma. Follows:Roche: Consultancy, Honoraria. Hillmen:Roche Pharmaceuticals: Honoraria, Research Funding, Speakers Bureau; GlaxoSmithKine: Honoraria, Speakers Bureau; Genzyme: Research Funding; MundiPharma: Honoraria, Speakers Bureau. Walewski:Janssen-Cilag: ; Hoffman La Roche: Honoraria, Institutional/personal grants, travel/accommodation expenses; Mundipharma: Honoraria; Celgene: Honoraria.

Abstract 857 Background: Follicular lymphoma (FL) is an incurable B-cell non-Hodgkin's lymphoma (NHL) representing ∼20% of all NHL. Rituximab (R) is approved for the treatment of CD20+ relapsed/refractory FL, and single-agent bortezomib (Vc; VELCADE®) has shown activity in heavily pretreated patients. Vc and R show additive activity in preclinical models, and the combination was active and well tolerated in a phase 2 study. This randomized, open-label, multi-center, international, phase 3 clinical trial (LYM3001) compared the efficacy and safety of Vc plus R (Vc-R) vs R alone in patients with relapsed or refractory, R-naive or R-sensitive FL. Methods: Patients with grade 1/2 measurable FL who had relapsed/progressed following prior therapy (time to progression [TTP] ≥6 months if prior R-containing therapy), ECOG performance status ≤2, and no peripheral neuropathy grade ≥2 were randomized (1:1) to receive 5-week cycles of Vc-R (Vc 1.6 mg/m2, d 1, 8, 15, 22, cycles 1–5, plus R 375 mg/m2, d 1, 8, 15, 22 in cycle 1 and d 1 only in cycles 2–5) or R alone (administered according to the same schedule as for the Vc-R arm). In both groups, treatment was administered for five cycles or until progression or unacceptable treatment-related toxicity. Randomization was stratified by FLIPI score (0–1 vs 2 vs ≥3), prior R therapy (yes vs no), time since last dose of anti-FL therapy (≤1 vs >1 year), and region (US vs EU vs rest of world). Primary endpoint was progression-free survival (PFS); secondary endpoints included overall response rate (ORR), complete response (CR) rate, TTP, and safety/tolerability. Response and progression were assessed by independent radiology committee (IRC) using the modified International Workshop Response Criteria. Planned sample size was 670 patients to provide 90% power (α=0.05, 2-sided) to detect a 33% improvement in median PFS with Vc-R vs R (i.e. 13.3 vs 10 months). Results: Between April 2006 and August 2008, 676 patients (intent-to-treat [ITT] population) were enrolled from 164 centers in 29 countries across Europe, the Americas, and Asia. Baseline characteristics were well balanced between the two arms; median age was 57 years (range 21–84), 54% were female, 75% were Caucasian and 21% were Asian. The majority of patients (93%) had an ECOG performance status of 0 or 1, 51% and 48% had grade 1 and 2 FL, respectively, and 41%, 35%, and 23% had high, intermediate, and low FLIPI score, respectively; 83% had Ann Arbor Stage III or IV, and 38% had bone marrow involvement at baseline. 33% of patients had received 3 or more prior lines of therapy (range 1–6+); 44% had received prior R therapy. The most common prior regimens were CHOP (38%), CVP (25%), single-agent R (17%), R-CHOP (12%), and R-CVP (11%). At a median follow-up of 33.9 months, a total of 440 PFS events were observed by IRC in the ITT population, 212 in the Vc-R arm and 228 events in the R arm. Median PFS improved from 334 days (95% CI: 278, 365) with R alone to 389 days (95% CI: 351, 456) with Vc-R; the hazard ratio was 0.822 (95% CI: 0.681, 0.991). This improvement is statistically significant with a 2-sided P-value of 0.039. The ORR was 63% with Vc-R vs 49% with R (P6 months) was 50% with Vc-R vs 38% with R (P=0.002). The median time to subsequent antilymphoma treatment was significantly improved in the Vc-R vs R arm (700 vs 537 days, P=0.027). Median OS was not reached in either group. Patients received a median 25 weeks treatment in both the Vc-R and R groups (range 5–40 and 5–35 in the Vc-R and R groups, respectively). Adverse events (AEs) were reported for 95% of Vc-R and 78% of R patients. The most common AEs were diarrhea (52% Vc-R, 8% R), nausea (29% Vc-R, 7% R), and pyrexia (25% Vc-R, 10% R). Most AEs were grade 1 or 2. Grade ≥3 AEs were reported in 46% of Vc-R and 21% of R patients; the most common grade ≥3 AEs were neutropenia (11% vs 4%) and diarrhea (7% vs 0%). Peripheral sensory neuropathy was reported in 17% of patients in the Vc-R arm vs 1% in the R arm; 3% vs 0% grade ≥3. 18% and 11% of Vc-R and R patients, respectively, had serious AEs, only 4% and 1% of patients discontinued due to drug-related AEs, and there were 9 and 4 on-treatment deaths, respectively. Conclusion: The addition of weekly Vc to R therapy in patients with relapsed FL was associated with statistically significant improvements in PFS, response rate, and time to next antilymphoma treatment, with acceptable additional toxicity. Disclosures: Coiffier: Johnson & Johnson: Honoraria. Off Label Use: Discussion of Velcade in NHL subtypes other than mantle cell lymphoma is included. Mayer:Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Rule:Johnson & Johnson: Consultancy, Speakers Bureau; Roche: Consultancy. Walewski:Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen-Cilag: Investigators fee. Crump:Millennium Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Johnson & Johnson: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy. Shpilberg:Johnson & Johnson: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Hermann:Millennium Pharmaceuticals: Research Funding. Parasuraman:Millennium Pharmaceuticals: Employment, Equity Ownership. Zhu:Johnson & Johnson: Employment. Enny:Johnson & Johnson: Employment, Equity Ownership. Theocharous:Johnson & Johnson: Employment. van de Velde:Johnson & Johson: Employment, Equity Ownership. Elsayed:Johnson & Johnson: Employment, Equity Ownership.

Abstract 3983 Background: Bortezomib is primarily metabolized by cytochrome P450 (CYP) 3A4 and 2C19 enzymes. Effects of co-administration of rifampicin (a potent CYP3A4 inducer) and dexamethasone (weak CYP3A4 inducer) on the pharmacokinetic (PK), pharmacodynamic (PD) and safety profiles of bortezomib were evaluated. Methods: Patients with relapsed or refractory multiple myeloma (MM) or non-Hodgkin's lymphoma (NHL) were enrolled in this open-label, 2-stage, parallel-group study. In stage 1, patients were randomized (1:1) to receive 3 cycles of bortezomib (1.3 mg/m2) on d 1, 4, 8, and 11 q3wk either alone or in combination with rifampicin 600 mg once-daily on d 4 to 10 of cycle 3 only. Stage 2 patients received bortezomib at same dose and schedule in combination with dexamethasone 40 mg once-daily on d 1 to 4 and d 9 to 12 of cycle 3 only. Patients could continue with bortezomib monotherapy for up to 10 cycles in case of clinical benefit. For PK/PD, blood samples were collected before and through 72 hours following bortezomib administration on d 11 of cycles 2 and 3. PK was the primary endpoint, secondary endpoints included PD (proteasome inhibition) and safety. Results: 61 patients were enrolled (39 MM, 22 NHL) in the study. 13 were treated with bortezomib + rifampicin, 18 with bortezomib + dexamethasone, and 30 with bortezomib only. Co-administration of rifampicin reduced the mean bortezomib maximum plasma concentration (Cmax) by approximately 23% (118 vs 93 ng/mL) and the mean area under plasma concentration-time curve from 0 to 72 hours (AUC72) by approximately 45% (223 vs 123 ng.h/mL). Co-administration of dexamethasone had no effect on mean AUC72 (179 vs 170 ng.h/mL). The mean bortezomib Cmax was 20% lower after co-administration of dexamethasone (140 vs 119 ng/mL); however this difference in Cmax was within the observed variability in Cmax during cycle 2 (CV=38%) and cycle 3 (CV=45%). Mean (SD) maximum percent proteasome inhibition (Emax) and area under percent proteasome inhibition-time curve from 0 to 72 hours (AUE72h) were comparable for bortezomib alone and in combination with rifampicin (Emax: 61.9 [4.56] vs. 62.3 [3.81] and AUE72h: 836 [323] vs. 777 [358]). Co-administration of dexamethasone did not affect the Emax (66.7 [4.27] vs. 61.8 [6.69]) or AUE72h (1329 [638] vs. 1157 [381]). Safety profiles were consistent with prior bortezomib experience in this population. Drug-related serious adverse events and treatment discontinuations were reported in 7/30 (23%) and 8/30 (27%) in bortezomib-only, in 3/13 (23%) and 3/13 (23%) in bortezomib + rifampicin, and 3/18 (17%) and 5/18 (28%) in bortezomib + dexamethasone subgroups. Investigator-assessed responses (CR+PR) were observed in 13/17 MM and 6/13 NHL patients in bortezomib-only, in 6/9 MM and 3/4 NHL patients in bortezomib + rifampicin, and in 10/13 MM and 2/5 NHL patients in bortezomib + dexamethasone subgroups. Conclusions: Co-administration of dexamethasone did not affect the PK or PD profiles of bortezomib. Co-administration of rifampicin reduced bortezomib exposure (AUC) by approximately 45%. Patients receiving bortezomib concomitantly with strong CYP3A4 inducers, such as rifampicin, should be monitored for reduction in clinical effect, while concomitant administration of weak CYP3A4 inducers, such as dexamethasone, is not expected to affect the bortezomib pharmacologic profile. Disclosures: Off Label Use: Discussion of Velcade in NHL subtypes other than mantle cell lymphoma is included. Rule:Johnson & Johson: Consultancy, Speakers Bureau; Roche: Consultancy. Walewski:Johnson & Johnson: Honoraria, Research Funding; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen-Cilag: Investigators fee. Shpilberg:Johnson & Johnson: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Feng:Johnson & Johnson: Employment. van de Velde:Johnson & Johnson: Employment, Equity Ownership. Patel:Johnson & Johnson: Employment, Equity Ownership. Skee:Johnson & Johnson: Employment. Girgis:Johnson & Johnson: Employment. Louw:Janssen-Cilag: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Key Oncologics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers-Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.

Introduction: Rituximab (R) is an integral component of therapy for B-cell lymphoid malignancies; bortezomib (Btz) has shown provocative single agent activity in Follicular Lymphoma (FL), Mantle Cell Lymphoma (MCL) and Waldenström’s Macroglobulinaemia (WM), providing the rationale for investigating the combination. Patients+Methods: Forty-five adult patients (pts.) (30 men, 15 women) with histologically confirmed recurrent CD20+ve FL, MCL or WM, median age 60 years (range 45-79), FL: 17, MCL: 18, WM: 10, stage III/IV 40 (93%), bone marrow (BM) infiltration 32 (73%), elevated LDH 22 (49%), performance status ≥1 22 (49%), were enrolled in a randomised trial comparing 2 schedules of Brz+R: Arm A (twice weekly) Btz: 1.3mg/m2 (on days 1, 4, 8, 11 of a 21-day cycle) and R: 375mg/m2 (on day 1) for 8 cycles, or Arm B (weekly) Btz: 1.6mg/m2 (on days 1, 8, 15, 22 of a 35-day cycle) and R: 375mg/m2 (on days 1, 8, 15, 22 of cycles 1 and 4) for 6 cycles (23 arm A, 22 arm B). The median number of previous treatments was 2 (range 1-7). Seventeen pts. had received a R-containing regimen, with response lasting >6 months, and 8 high-dose treatment. Response was evaluated using the IWR criteria (Cheson et al, JCO17: 1244, 1999) and the updated response criteria from the 3rd International Workshop on WM (Treon et al, Blood107: 3442, 2006) Results: Ability to deliver the therapy, toxicity and efficacy were equivalent in both arms. The median number of cycles given in arm A was 4 and 5 in arm B. Haematological toxicity (grade≥3: anaemia 0%, neutropenia 25%, thrombocytopenia 22%) was significantly influenced by the high percentage of pts. with BM infiltration and concomitant cytopenia on entry to the trial. The most common non-haematological adverse events were fatigue (76%), nausea (56%), diarrhoea (56%), lethargy (46%). Neurotoxicity occurred in 19 pts. (46%) (10 pts. grade 1, 7 pts. grade 2, 2 pts. grade 3). Btz dose was reduced in 7 pts.; 5 doses were omitted because of neuro or haematological toxicity. In 16 pts., treatment was delayed by 1-14 days and in 24 pts. treatment was stopped prematurely. The reasons for stopping treatment were: treatment-related toxicity 11 pts., progressive disease 9 pts., patient’s preference 3 pts., myocardial infarction 1 pt. One pt. was excluded having been found ineligible post randomisation. Thirty-nine pts. (21 arm A, 18 arm B) are evaluable for response so far, one having only received 1 cycle of therapy, which had to be discontinued because of excessive toxicity. 15/32 were in remission (CR, CRu, PR) at the completion of therapy, 7/7 at “mid-therapy” assessment, and 5 have yet to be evaluated. Thus the overall response rate (RR) presently is 22/39 (56%) (CR, CRu, PR), FL 44%, MCL 46%, WM 90%. Conclusions: The combination was active in pts. with recurrent NHL especially WM (RR 90%), despite multiple previous treatments, The weekly schedule is preferable being more convenient, as efficacious and no more toxic. Further investigation is warranted, despite not insignificant therapy compromising toxicity.

Cutaneous reactions to imatinib therapy are increasingly being recognized, with up to 21% of patients experiencing mild to moderate reactions at doses of 600 mg and higher.[1][1] A recent case report of Stevens-Johnson syndrome complicating the use of imatinib[2][2] expressed caution in the