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Introduction: Multiple studies have demonstrated that diffuse large B-cell lymphoma (DLBCL) can be divided into subgroups based on their biology. However, these biological subgroups overlap clinically. While R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) remains the standard of care for treating patients with DLBCL, predicting which patients will not benefit from such therapy is important so that alternative therapy or clinical trials can be considered. Most of the studies stratifying patients select biomarkers first, then explore how these biomarkers can stratify patients based on outcome. We explored the potential of using machine learning to first group patients with DLBCL based on survival, then isolating the biomarkers necessary for predicting these survival subgroups. Methods: RNA was extracted from tissue paraffin blocks from 379 R-CHOP treated patients with de novo DLBCL, and from 247 patients with extranodal DLBCL. A targeted hybrid capture RNA panel of 1408 genes was used for next generation sequencing (NGS). Sequencing was performed using an Illumina NextSeq 550 System platform. Ten million reads per sample in a single run were required, and the read length was 2 × 150 bp. An expression profile was generated from the sequencing coverage profile of each individual sample using Cufflinks. A machine learning system was developed to classify patients into four groups based on their overall survival. This machine learning approach based on Naïve Bayesian algorithm was also used to discover the relevant subset of genes with which to classify patients into each of the four survival groups. To eliminate the underflow problem commonly associated with the standard Naïve Bayesian classifiers, we applied Geometric Mean Naïve Bayesian (GMNB) as the classifier to predict the survival group for each patient. Results: Using machine learning, patients were first divided into two groups: short survival (S) and long survival (L). To refine this model, we used the same approach and divided the patients in each group into two subgroups, generating four groups: long survival in the long group (LL), short survival in the long group (LS), long survival in the short group (SL), and short survival in the short group (SS). The hazard ratio for this model was 0.174 (confidence interval: 0.120-0.251), and P-value Conclusions: Using a novel machine learning approach with the expression levels of 180 genes, we developed a model that can reliably stratify patients with DLBCL treated with R-CHOP into four survival subgroups. This model can be used to identify patients who may not respond well to R-CHOP to be considered for alternative therapy and clinical trials. Figure 1 Figure 1. Disclosures Hsi: AbbVie Inc, Eli Lilly: Research Funding. Ferreri: Ospedale San Raffaele srl: Patents & Royalties; BMS: Research Funding; Pfizer: Research Funding; Beigene: Research Funding; Hutchison Medipharma: Research Funding; Amgen: Research Funding; Genmab: Research Funding; ADC Therapeutics: Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; PletixaPharm: Membership on an entity's Board of Directors or advisory committees; x Incyte: Membership on an entity's Board of Directors or advisory committees; Adienne: Membership on an entity's Board of Directors or advisory committees. Piris: Millenium/Takeda, EUSA, Jansen, NanoString, Kyowa Kirin, Gilead and Celgene.: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Winter: BMS: Other: Husband: Data and Safety Monitoring Board; Actinium Pharma: Consultancy; Janssen: Other: Husband: Consultancy; Agios: Other: Husband: Consultancy; Gilead: Other: Husband: Consultancy; Epizyme: Other: Husband: Data and Safety Monitoring Board; Ariad/Takeda: Other: Husband: Data and Safety Monitoring Board; Merck: Consultancy, Honoraria, Research Funding; Novartis: Other: Husband: Consultancy, Data and Safety Monitoring Board; Karyopharm (Curio Science): Honoraria.

With the introduction of large-scale molecular profiling methods and high-throughput sequencing technologies, the genomic features of most lymphoid neoplasms have been characterized at an unprecedented scale. Although the principles for the classification and diagnosis of these disorders, founded on a multidimensional definition of disease entities, have been consolidated over the past 25 years, novel genomic data have markedly enhanced our understanding of lymphomagenesis and enriched the description of disease entities at the molecular level. Yet, the current diagnosis of lymphoid tumors is largely based on morphological assessment and immunophenotyping, with only few entities being defined by genomic criteria. This paper, which accompanies the International Consensus Classification of mature lymphoid neoplasms, will address how established assays and newly developed technologies for molecular testing already complement clinical diagnoses and provide a novel lens on disease classification. More specifically, their contributions to diagnosis refinement, risk stratification, and therapy prediction will be considered for the main categories of lymphoid neoplasms. The potential of whole-genome sequencing, circulating tumor DNA analyses, single-cell analyses, and epigenetic profiling will be discussed because these will likely become important future tools for implementing precision medicine approaches in clinical decision making for patients with lymphoid malignancies.

Background: The rapid global spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains the international public health concern of the decade. Early clinical data suggest that patients (pts) with hematologic malignancies are vulnerable to severe forms of SARS-CoV-2 and have higher mortality rates than the general population. Greater understanding of risk factors and outcomes associated with SARS-CoV-2 in pts with hematologic malignancies is crucial in order to develop individualized risk-benefit analyses to guide care. Herein, we report a cohort study from a Comprehensive Cancer Center evaluating outcomes in pts with hematologic malignancies who developed SARS-CoV-2. Methods: Adult pts at Northwestern Memorial Hospital with a current/prior hematologic malignancy and laboratory-confirmed SARS-CoV-2 infection confirmed by quantitative RT-PCR from nasopharyngeal swabs between March-July, 2020 were identified using electronic health records. Data were collected and analyzed based on epidemiologic, laboratory, and clinical characteristics. Severity of illness was defined by level of care (ambulatory, inpatient), need for advanced respiratory support (high flow nasal cannula, BiPAP, mechanical ventilation), incidence of thrombotic events, incidence of acute kidney injury (AKI), and/or death. Statistical analyses of risk factors, severity, and outcomes were performed. Subgroup analyses based on antineoplastic treatment status and receipt of SARS-CoV-2 -directed therapy were made. Active cancer treatment was defined as antineoplastic therapy within 12 months of SARS-CoV-2 diagnosis. Results: Demographic (Table 1) and clinical (Table 2) data were recorded from 73 SARS-CoV-2 infected pts. Sixty (80%) pts had lymphoid and 15 (20%) had myeloid neoplasms, 2 with concurrent lymphoid and myeloid neoplasms. Thirty-seven (51%) pts were undergoing active treatment for their malignancy. Twenty-one pts (29%) were managed in the ambulatory setting while 52 (71%) required hospital admission. Twenty-five (34%) pts required advanced respiratory support including 14 (19%) who required mechanical ventilation. Four pts (6%) had thrombotic events and 31 (42%) received SARS-CoV-2-directed therapies. Sixteen pts (22%) died during the study period. Pts on active cancer treatment had higher rates of hospital admission (81% v 60%; p=0.05) and AKI (51% v 29%; p=0.04) but similar rates of death compared with pts not on active treatment (24% v 20%; p=0.66) (Table 3). Comparing pts who received SARS-CoV-2 -directed therapy versus no therapy: pts on therapy had longer median lengths of stay (11 v 7 days; p=0.04) and higher rates of hospital admission (94% v 55%; p=0.0003) but similar rates of death (23% v 21%; p=0.91); pts in the ICU on SARS-COV-2 -directed therapy had lower rates of death (38% v 88% p=0.02) than pts who did not receive such therapy (Table 4). Twenty-six pts (36%) were tested for viral clearance, defined as two serial negative swabs ≥24 hours apart. Of these, 17 (65%) achieved clearance with a median time of 51 days (range 15-119 days). Thirteen pts (18%) had antibody (Ab) testing. Ten (77%) had detectable Abs: 8 were positive for IgG, 1 for IgG and IgM, and 1 had unspecified positivity. Notably, all 3 pts with undetectable Abs were on active cancer treatment. Conclusion: We demonstrate that pts with hematologic malignancies are exceptionally vulnerable to severe forms of SARS-CoV-2 with high mortality rates. The incidence of thrombotic events was low, an unexpected finding in the setting of a hyperinflammatory syndrome. Prolonged time to viral clearance was observed, a finding which may cause potential delays in the resumption of cancer-directed therapies. Notably, the majority of pts who received antibody testing had detectable antibodies suggesting that pts with hematologic malignancies may be able to mount an immune response to early vaccination. Accordingly, close monitoring, aggressive therapy, and early vaccination, when available, may be warranted for this population. Larger studies are needed to confirm our findings and help guide management of pts with hematologic malignancies during the SARS-CoV-2 pandemic. Disclosures Altman: Bristol-Myers Squibb: Consultancy; Janssen: Consultancy; Immune Pharmaceuticals: Consultancy; Syros: Consultancy; Genentech: Research Funding; Novartis: Consultancy; Amphivena: Research Funding; Amgen: Research Funding; Aprea: Research Funding; ImmunoGen: Research Funding; Celgene: Research Funding; Boehringer Ingelheim: Research Funding; Fujifilm: Research Funding; Kartos: Research Funding; AbbVie: Other: advisory board, Research Funding; Kura Oncology: Other: Scientific Advisory Board - no payment accepted, Research Funding; BioSight: Other: No payment but was reimbursed for travel , Research Funding; Daiichi Sankyo: Other: Advisory Board - no payment but was reimbursed for travel; Agios: Other: advisory board, Research Funding; Glycomimetics: Other: Data safety and monitoring committee; Astellas: Other: Advisory Board, Speaker (no payment), Steering Committee (no payment), Research Funding; Theradex: Other: Advisory Board; ASH: Consultancy; Cancer Expert Now: Consultancy; France Foundation: Consultancy; PeerView: Consultancy; PrIME Oncology: Consultancy. Winter:Delta Fly Pharma: Consultancy; Amgen: Consultancy; Epizyme: Other: DSMB; CVS/Caremark: Consultancy; Ariad/Takeda: Consultancy; Norvartis: Consultancy, Other: DSMB; Merck: Membership on an entity's Board of Directors or advisory committees, Other: advisory board; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: advisory board. Gordon:Zylem Biosciences: Patents & Royalties: Patents, No Royalties. Pro:Verastem Oncology: Research Funding. Ma:TG Therapeutics: Research Funding; Juno: Research Funding; Novartis: Research Funding; Kite: Consultancy, Honoraria; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; BeiGene: Honoraria, Research Funding, Speakers Bureau; Bioverativ: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau. Karmali:BMS/Celgene/Juno: Honoraria, Other, Research Funding, Speakers Bureau; Takeda: Research Funding; Karyopharm: Honoraria; Gilead/Kite: Honoraria, Other, Research Funding, Speakers Bureau; AstraZeneca: Speakers Bureau; BeiGene: Speakers Bureau.

Since the publication of the Revised European-American Classification of Lymphoid Neoplasms in 1994, subsequent updates of the classification of lymphoid neoplasms have been generated through iterative international efforts to achieve broad consensus among hematopathologists, geneticists, molecular scientists, and clinicians. Significant progress has recently been made in the characterization of malignancies of the immune system, with many new insights provided by genomic studies. They have led to this proposal. We have followed the same process that was successfully used for the third and fourth editions of the World Health Organization Classification of Hematologic Neoplasms. The definition, recommended studies, and criteria for the diagnosis of many entities have been extensively refined. Some categories considered provisional have now been upgraded to definite entities. Terminology for some diseases has been revised to adapt nomenclature to the current knowledge of their biology, but these modifications have been restricted to well-justified situations. Major findings from recent genomic studies have impacted the conceptual framework and diagnostic criteria for many disease entities. These changes will have an impact on optimal clinical management. The conclusions of this work are summarized in this report as the proposed International Consensus Classification of mature lymphoid, histiocytic, and dendritic cell tumors. ispartof: BLOOD vol:140 issue:11 pages:1229-1253 ispartof: location:United States status: published

Pembrolizumab, a humanized IgG4 monoclonal antibody targeting programmed death-1 protein, has demonstrated efficacy in relapsed/refractory classical Hodgkin lymphoma (cHL). To assess the complete metabolic response (CMR) rate and safety of pembrolizumab monotherapy in newly diagnosed cHL, we conducted a multicenter, single-arm, phase 2 investigator-initiated trial of sequential pembrolizumab and doxorubicin, vinblastine, and dacarbazine (AVD) chemotherapy. Patients ≥18 years of age with untreated, early, unfavorable, or advanced-stage disease were eligible for treatment. Thirty patients (early unfavorable stage, n = 12; advanced stage, n = 18) were treated with 3 cycles of pembrolizumab monotherapy followed by AVD for 4 to 6 cycles, depending on stage and bulk. Twelve had either large mediastinal masses or bulky disease (>10 cm). After pembrolizumab monotherapy, 11 patients (37%) demonstrated CMRs, and an additional 7 of 28 (25%) patients with quantifiable positron emission tomography computed tomography scans had >90% reduction in metabolic tumor volume. All patients achieved CMR after 2 cycles of AVD and maintained their responses at the end of treatment. With a median follow-up of 22.5 months (range, 14.2-30.6) there were no changes in therapy, progressions, or deaths. No patients received consolidation radiotherapy, including those with bulky disease. Therapy was well tolerated. The most common immune-related adverse events were grade 1 rash (n = 6) and grade 2 infusion reactions (n = 4). One patient had reversible grade 4 transaminitis and a second had reversible Bell’s palsy. Brief pembrolizumab monotherapy followed by AVD was both highly effective and safe in patients with newly diagnosed cHL, including those with bulky disease. This trial was registered at www.clinicaltrials.gov as #NCT03226249.

Diffuse large B-cell lymphoma (DLBCL) is the most common type of lymphoma with high mutation burdens but a low response rate to immune checkpoint inhibitors. In this study, we performed targeted next-generation sequencing and fluorescent multiplex immunohistochemistry, and investigated the clinical significance and immunological effect of mutation numbers in 424 DLBCL patients treated with standard immunochemotherapy. We found that KMT2D and TP53 nonsynonymous mutations (MUT) were significantly associated with increased nonsynonymous mutation numbers, and that high mutation numbers (MUThigh) were associated with significantly poorer clinical outcome in germinal center B-cell-like DLBCL with wild-type TP53. To understand the underlying mechanisms, we identified a gene-expression profiling signature and the association of MUThigh with decreased T cells in DLBCL patients with wild-type TP53. On the other hand, in overall cohort, MUThigh was associated with lower PD-1 expression in T cells and PD-L1 expression in macrophages, suggesting a positive role of MUThigh in immune responses. Analysis in a whole-exome sequencing dataset of 304 patients deposited by Chapuy et al. validated the correlation of MUT-KMT2D with genomic complexity and the significantly poorer survival associated with higher numbers of genomic single nucleotide variants in activated B-cell–like DLBCL with wild-type TP53. Together, these results suggest that KMT2D inactivation or epigenetic dysregulation has a role in driving DLBCL genomic instability, and that genomic complexity has adverse impact on clinical outcome in DLBCL patients with wild-type TP53 treated with standard immunochemotherapy. The oncoimmune data in this study have important implications for biomarker and therapeutic studies in DLBCL.

Introduction The treatment of aggressive B-cell NHL has evolved rapidly over the last 5 years, owing to the FDA approval of 3 CD19 CAR T-cell constructs (CARTs) along with other novel targeted therapies. Real world practice data suggest that CARTs have been successfully administered in populations typically excluded from clinical trials. However, data on how to best utilize novel targeted agents as a pathway to CARTs and feasibility of CARTs in rare histologies remains limited. This retrospective multicenter study describes patient (pt) selection and practice patterns in pts treated with CD19 CARTs and provides insight on feasibility of CARTs in special populations. Methods Adult pts with R/R aggressive B-cell NHL treated with CD19 CARTs between 2015- 2020 across 12 US academic centers were identified. Data on demographic and clinical characteristics, disease and toxicity outcomes were collected. Univariate analyses (UVA) were performed to determine impact of demographic/clinical variables on survival. Survival curves were calculated using Kaplan-Meier method. Subgroup analysis was performed for pts with secondary central nervous system lymphoma (sCNSL). Results Clinical and demographic features were recorded from 400 pts (Table 1). Median age was 59 years (range 18-84). Of 271 pts with immunohistochemistry data, 79 (29%) had double-expressor lymphoma. Of 178 pts with FISH data captured, 62 (35%) had double/triple-hit lymphoma. Most common histological subtypes included 271 (68%) pts with de novo DLBCL, 81 (20%) with transformed FL, 13 (3%) with Richter's syndrome, and 8 (2%) with PMBCL. Rare histologies included 7 (2%) with transformed MZL, 5 (1%) with PTLD and 2 (0.5%) with grey zone lymphoma. 24 (6%) pts had sCNSL at time of CART apheresis. Two (0.5%) pts were HIV-positive. Median number of lines of therapy prior to CART was 2 (range 1-8); 182 (46%) pts received ≥ 3 lines. 114 (28%) pts previously had an autologous stem cell transplant. Targeted therapies used as salvage regimens at any point prior to CART are listed in Table 2: commonly used salvage targeted therapies included lenalidomide based therapy (imids, n=37, 9%), BTK inhibitors (BTKis, n=30, 8%), checkpoint inhibitors (CBIs, n=17, 4%) and polatuzumab-containing regimens (n=10, 3%). 2 (1%) pts received loncastuximab, and no pts received tafasitamab. Six (1.5%) pts proceeded to CART despite complete response to most recent pre-CART therapy. 191 (48%) pts received bridging between apheresis and CART infusion, choice of bridging noted in Table 2: the majority received chemotherapy (n=103, 54%); 28 (15%) received radiation (XRT); 25 (13%), 24 (13%) and 18 (9%) pts received imids, polatuzumab-containing regimens, or BTKis, respectively. With median follow-up of 22.4 months (mo) for the overall group, median (m) PFS was 11 mo (n=363); mOS, was 27 mo (n=397; Fig 1). Pts with sCNSL had a mPFS and mOS of 2 and 4 mo, respectively (Fig 1). On UVA, factors predicting poorer PFS and OS in the overall group included ≥3 pre-CART lines (p For outcomes according to bridging regimens: mPFS after CART for most commonly used systemic bridging therapies was 86 days (d) for platinum-based chemotherapy, 77 d for imids, 90 d for BTKis, 98 d for polatuzumab-bendamustine/rituximab, and 274 d for XRT. Median PFS for XRT bridging (274 d) was statistically better when compared to mPFS for listed systemic therapies combined (p Conclusion Survival outcomes with CARTs in our data set are consistent with those reported in clinical trial settings. CARTs are utilized in real world practice in rare subsets of aggressive R/R B-cell NHL not routinely included in clinical trials. Despite early data suggesting pts with sCNSL benefit from CART, our data suggest outcomes with CART are dismal in this group. Targeted therapies including imids, polatuzumab, BTKis and CBIs are feasible choices for salvage and/or bridging as a pathway to CARTs. Bridging with XRT resulted in improved mPFS post CART as compared to bridging with systemic therapies and suggests differences in pt selection for each with systemic therapies likely favored in those with more widespread disease burden. Minimal use of CD19-targeted agents pre-CART is attributed to later approval of these agents and concern for potential loss of CD19 antigen leading to CART resistance. Figure 1 Figure 1. Disclosures Cohen: Janssen, Adicet, Astra Zeneca, Genentech, Aptitude Health, Cellectar, Kite/Gilead, Loxo, BeiGene, Adaptive: Consultancy; Genentech, BMS/Celgene, LAM, BioINvent, LOXO, Astra Zeneca, Novartis, M2Gen, Takeda: Research Funding. Shouse: Kite Pharma: Speakers Bureau; Beigene: Honoraria. Hess: ADC Therapeutics: Consultancy; BMS: Speakers Bureau. Stephens: Beigene: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; Epizyme: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Adaptive: Membership on an entity's Board of Directors or advisory committees; Arqule: Research Funding; Mingsight: Research Funding; JUNO: Research Funding; Celgene: Consultancy; CSL Behring: Consultancy; AstraZeneca: Consultancy; Abbvie: Consultancy; Innate Pharma: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding. Ma: Loxo: Research Funding; AstraZeneca: Honoraria, Research Funding, Speakers Bureau; Juno: Research Funding; Beigene: Research Funding, Speakers Bureau; Abbvie: Honoraria, Research Funding; Janssen: Research Funding, Speakers Bureau; TG Therapeutics: Research Funding; Pharmacyclics: Research Funding, Speakers Bureau. Winter: BMS: Other: Husband: Data and Safety Monitoring Board; Actinium Pharma: Consultancy; Janssen: Other: Husband: Consultancy; Gilead: Other: Husband: Consultancy; Agios: Other: Husband: Consultancy; Epizyme: Other: Husband: Data and Safety Monitoring Board; Merck: Consultancy, Honoraria, Research Funding; Novartis: Other: Husband: Consultancy, Data and Safety Monitoring Board; Ariad/Takeda: Other: Husband: Data and Safety Monitoring Board; Karyopharm (Curio Science): Honoraria. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. Danilov: Astra Zeneca: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Honoraria, Research Funding; Takeda Oncology: Research Funding; TG Therapeutics: Consultancy, Research Funding; Abbvie: Consultancy, Honoraria; Beigene: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; Gilead Sciences: Research Funding; Bristol-Meyers-Squibb: Honoraria, Research Funding; Rigel Pharm: Honoraria; Bayer Oncology: Consultancy, Honoraria, Research Funding; SecuraBio: Research Funding. Shah: Umoja: Consultancy; Legend: Consultancy; Kite: Consultancy; Miltenyi Biotec: Consultancy, Honoraria, Research Funding; Lily: Consultancy, Honoraria, Research Funding; Epizyme: Consultancy; Incyte: Consultancy. Barta: Seagen: Honoraria; Daiichi Sankyo: Honoraria; Acrotech: Honoraria; Kyowa Kirin: Honoraria. Epperla: Genzyme: Honoraria; Karyopharm: Other: Ad Board; Beigene: Speakers Bureau; Verastem: Speakers Bureau. Torka: TG Therapeutics: Membership on an entity's Board of Directors or advisory committees. Karmali: Epizyme: Consultancy; BeiGene: Consultancy, Speakers Bureau; EUSA: Consultancy; Roche: Consultancy; AstraZeneca: Speakers Bureau; Morphosys: Consultancy, Speakers Bureau; Karyopharm: Consultancy; Takeda: Research Funding; BMS/Celgene/Juno: Consultancy, Research Funding; Janssen/Pharmacyclics: Consultancy; Genentech: Consultancy; Kite, a Gilead Company: Consultancy, Research Funding, Speakers Bureau.

Background: Immunotherapeutic strategies targeting the PD-1/PD-L1 pathway have become part of standard of care for patients with classical Hodgkin lymphoma (cHL). Recent studies have investigated combinations of anti-PD-1 antibodies with conventional chemotherapy and demonstrated significant clinical benefits in the first-line setting. A phase 2 trial demonstrated that induction with pembrolizumab monotherapy followed by chemotherapy was highly effective and safe in patients with newly diagnosed, early unfavorable, or advanced-stage cHL (Allen PB et al. Blood. 2020;137[10]:1318-1326). The KEYNOTE-C11 open-label phase 2 study will build on this concept by evaluating the safety and efficacy of sequential pembrolizumab monotherapy and chemotherapy followed by pembrolizumab consolidation in adult patients with newly diagnosed, early unfavorable, or advanced-stage cHL. Study Design and Methods: Patients must have newly diagnosed, histologically confirmed, untreated (no prior chemotherapy, immunotherapy, or other systemic therapy for cHL), early unfavorable cHL (Ann Arbor stage I/II plus ≥1 National Comprehensive Cancer Network unfavorable risk factor) or advanced-stage cHL (Ann Arbor stage III/IV) and measurable disease per Lugano 2014 classification. Approximately 140 patients will be enrolled. All patients will receive pembrolizumab 200 mg IV every 3 weeks (Q3W) for 3 cycles followed by PET to determine response to pembrolizumab monotherapy. After pembrolizumab induction, all patients will receive 2 cycles of AVD (day 1 and day 15 Q4W) and undergo another assessment by PET (PET 3) to determine the next treatment course. Patients with negative findings on PET 3 (≤3 on the Deauville 5-point scale) will receive 2-4 additional cycles of AVD, depending on stage and bulk of disease; those with nonbulky early unfavorable disease will receive 2 cycles, and all others will proceed to 4 cycles of AVD chemotherapy. Patients who are PET 3+ (≥4 on the FDG-PEG 5-point scale) and aged Disclosures Winter: Epizyme: Other: Husband: Data and Safety Monitoring Board; Agios: Other: Husband: Consultancy; Gilead: Other: Husband: Consultancy; Janssen: Other: Husband: Consultancy; Actinium Pharma: Consultancy; BMS: Other: Husband: Data and Safety Monitoring Board; Ariad/Takeda: Other: Husband: Data and Safety Monitoring Board; Merck: Consultancy, Honoraria, Research Funding; Novartis: Other: Husband: Consultancy, Data and Safety Monitoring Board; Karyopharm (Curio Science): Honoraria. Nahar: Merck: Current Employment. Kim: Merck: Current Employment, Other: Current Stockholder. Marinello: Merck & Co., Inc.: Current Employment, Other: Current Stockholder.

Background: Genomic copy number alterations (CNAs) of chromosome 9p24.1 characterize classic Hodgkin lymphoma (cHL) leading to increased expression of programmed cell death ligands -1 and -2 (PD-L1 and PD-L2). Amplifications and high level copy number gains (CNG) have been associated with advanced stage cHL and inferior treatment outcomes with standard chemotherapy. Few studies have assessed 9p24.1 genomic alterations in the frontline setting in the context of PD-1 blockade monotherapy. We conducted a phase 2 clinical trial of sequential pembrolizumab (PEM) x 3 followed by doxorubicin, vinblastine, and dacarbazine (AVD) chemotherapy (4-6 cycles) in newly diagnosed cHL. Interim response to single agent PEM was assessed by PET-CT and by decline in metabolic tumor volume (MTV). Herein, we report updates after extended follow-up of patients (median 33.1 months), and results of correlative studies analyzing 9p24.1 CNAs and PD-1 pathway expression. Methods: Pre-treatment diagnostic biopsy specimens were double stained for PD-L1 (E1L3N, XP Cell Signaling) and PAX5, single stained for PD-L2 and pSTAT3, and scored by two expert hematopathologists (QC, LBS) for percentage positive cells and intensity of staining. A modified H score was calculated as the product of staining intensity (0-3) and percentage of positive tumor cells (0-100%), ranging from 0 - 300 was calculated for PD-L1, PD-L2, and pSTAT3. Fluorescence in situ hybridization (FISH) to assess chromosome 9p24.1 CNAs was performed by co-hybridizing PD-L1/PD-L2 probes (target) with the centromeric 9 probe (control). In each case, the percentage and magnitude of 9p24.1 CNAs were evaluated. Four FISH categories were defined based on the target:control ratio and total copy numbers (CNs) of the target per Hodgkin Reed-Sternberg (HRS) cell to include: amplification (ratio≥3), copy number gain (CNGs) (1≤ratio The relationships between PD-1 pathway markers, genomic alterations, and response to single agent PEM by MTV were assessed statistically using Fisher's Exact test, Kruskal-Wallis test, or Spearman's rank correlation as appropriate. PD-L1 H Scores were grouped into terciles of approximately equal size for categorical analysis. Response was defined as a complete metabolic response (CMR), ≥ 90% reduction in MTV (near CMR), or partial response with < 90% reduction by MTV (PR). Kaplan-Meier curves were used to analyze progression-free survival (PFS) and overall survival (OS). Results: Thirty patients were enrolled from September 2017 through August 1, 2019; 28 had tissue available for FISH analysis and 29 for immunohistochemistry. Patient responses to single agent PEM were PMR in 11 (36.7%), near-CMR in 8 (26.7%), and CMR in 11 (36.7%). CMR rate following AVD x 2 was 100%. With the extended follow-up (median 33.1 months, range 26.0-43.0), PFS and OS both remained at 100% (Figures 1a, 1b). Among 28 cases with available FISH analysis, all patients demonstrated genomic alterations in 9p24.1. The highest level alteration was amplification in 14 patients (50%) and copy number gain in 14 (50.0%) Six of 22 examined cases were EBER-positive. Forty-one percent (n=7) of patients with a CMR or near CMR had amplifications in 9p24.1, compared to 64% (n=7) with a PMR following PEM monotherapy (p=0.2). The median PD-L1 H score was 215 (range 20-300). Of 29 patients assessed, 28% had PD-L1 H scores in the first tercile (H-score 1-190), 34% in the second tercile (190-240), and 38% in the third tercile (240-300). There was no association between response to single agent PEM and 9p24.1 alteration, PD-L1, PD-L2 or STAT3 H-scores, % residual disomy, or EBER status (see Figure 1c for PD-L1 results). Conclusions: We found that after extended follow-up, sequential pembrolizumab and AVD chemotherapy remains a highly effective strategy with 100% of patients remaining alive without relapse. The high response rates observed at all PD-L1/PD-L2 levels in this clinical study suggest that even low levels of PD ligand expression may be sufficient for response to PD-1 blockade in previously untreated cHL. We gratefully acknowledge support from Merck & Co. Figure 1 Figure 1. Disclosures Allen: Kyowa Kirin: Consultancy; Secure Bio: Consultancy; ADC Therapeutics: Consultancy; MorphoSys: Consultancy; Epizyme: Consultancy. Advani: Astellas/Agensys: Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Bristol Myer Squibb: Membership on an entity's Board of Directors or advisory committees; Cell Medica: Membership on an entity's Board of Directors or advisory committees; Forty Seven: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genetech Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceutical: Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Kura: Research Funding; Kyowa: Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Millenium: Research Funding; Pharmacyclics: Consultancy, Research Funding; Portola Pharmaceuticals: Consultancy; Regeneron: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. Winter: Actinium Pharma: Consultancy; BMS: Other: Husband: Data and Safety Monitoring Board; Novartis: Other: Husband: Consultancy, Data and Safety Monitoring Board; Ariad/Takeda: Other: Husband: Data and Safety Monitoring Board; Epizyme: Other: Husband: Data and Safety Monitoring Board; Agios: Other: Husband: Consultancy; Gilead: Other: Husband: Consultancy; Janssen: Other: Husband: Consultancy; Karyopharm (Curio Science): Honoraria; Merck: Consultancy, Honoraria, Research Funding.

Background: DLBCL is highly heterogeneous in underlying biology and clinical behavior. Several high-risk disease features and poor prognostic factors are associated with a higher propensity for refractory disease or relapse after standard R-CHOP therapy; these subset patients require novel strategies to improve upon outcomes. Single-agent TAK-659, a novel oral SYK inhibitor, has demonstrated efficacy in heavily pre-treated DLBCL (Gordon et al., Clin Cancer Res, 2020). We report results of a phase I single institution, single arm dose escalation study that assessed safety of 1 st line treatment with R-CHOP and adjunctive TAK-659 for treatment naïve high-risk DLBCL. Methods: Patients aged ≥18 years, ECOG 0-2 with untreated stage I-IV DLBCL with high-risk features defined as, ABC/non-GCB subtype, high-intermediate or high-risk NCCN-IPI (score ≥4), MYC gene rearranged by FISH including double hit lymphoma (DHL), double expressing DLBCL (DEL; overexpression of MYC ≥40% AND BCL2 ≥50% by IHC respectively), or previously treated transformed low-grade lymphoma without prior exposure to anthracycline, were eligible. Patients were treated with R-CHOP for 1 cycle on or off study followed by combined treatment with R-CHOP and TAK-659 for an additional 5 cycles on study. TAK-659 was dosed daily with dosing escalated from 60mg (dose level 1), to 80mg (dose level 2) to 100mg (dose level 3) based on a 3+3 design. The primary objective was to determine the safety and establish the maximum tolerated dose of TAK-659 when combined with R-CHOP in the front-line treatment of high-risk DLBCL. Secondary objectives were to assess preliminary efficacy of this combination as determined by overall response rate (ORR) by PET-CT (Lugano 2014 criteria), progression free survival (PFS), overall survival (OS) and establish the pharmacokinetics of TAK-659 according to dose. Results: 12 pts were enrolled from Dec 2019 to Nov 2021. The median age was 64 yrs (range 25-75); 8 (67%) had stage III/IV disease, 4 (33%) with high risk NCCN-IPI ≥ 4. Histology included 7 (58%) with de novo DLBCL (4 GCB, 3 non-GCB subtype DLBCL) including 7 (58%) with DEL, 3 (25%) with transformed FL, 1 (8%) with Richter's and 1 (8%) with DHL. Dose level 3 (100 mg) was established as the MTD. PKs were measured pre- and post-dose D1 and D15 of cycle 2; Cuzick's test signaled an increase in AUC by dose level on D1 (p = 0.01) but not on D15 (Fig 1). ORR was 100% (CR 92%; Fig 2). With a median follow-up of 14.2 months, 1 pt had primary refractory disease (ABC and DEL), 2 pts with CR subsequently progressed (1 non-GC DLBCL, 1 Richter's) and 1 died of cardiogenic shock unrelated to study drug. The 12-month PFS and OS rates were 82% and 90% respectively with estimated 18-month PFS and OS rates of 68% and 90% respectively. The most common treatment related adverse events (TRAEs) attributed to TAK-659 were lymphopenia (n=12, 100%), infection (6=, 50%), AST elevation (n = 12, 100%) and ALT elevation (n = 10, 83%) (Table). Incidence and severity of transaminitis was consistent with prior reports for this agent. Most common grade 3/4 toxicities were hematologic. Median number of cycles of TAK-659 delivered was 5 (range 3-5). TRAEs led to TAK-659 dose modifications in 8 (67%) pts, though none at dose level 1: 2 (17%) required permanent dose reductions (both for lung infections), while 5 (42%) required discontinuation (4 for infection, and 1 for febrile neutropenia). R-CHOP administration was delayed in 2 pts because of TAK-659 related TRAEs. Aside from dose modifications of vincristine for peripheral neuropathy, no additional dose modifications for R-CHOP were needed. Infections encountered included bacterial and opportunistic infections (1 each for PJP, CMV and aspergillosis) and 1 case of COVID. Growth factor prophylaxis and anti-fungal therapy were not mandated; PJP prophylaxis was advised for CD4 counts < 200 at initial diagnosis. Conclusion: TAK-659, a novel SYK inhibitor combined with R-CHOP in pts with newly diagnosed high-risk DLBCL including DLBCL transformed from follicular lymphoma and DEL produces high CR rates; survival at 12 months appears promising. A dose of 60 mg was well tolerated, did not require dose modifications and maintained a similar AUC to the MTD of 100 mg with ongoing treatment. Opportunistic infections were noted with this treatment combination suggesting that patients should receive aggressive anti-microbial prophylaxis with future evaluation of this combination. Figure 1 Figure 1. Disclosures Karmali: BeiGene: Consultancy, Speakers Bureau; Morphosys: Consultancy, Speakers Bureau; Kite, a Gilead Company: Consultancy, Research Funding, Speakers Bureau; Takeda: Research Funding; Karyopharm: Consultancy; EUSA: Consultancy; Janssen/Pharmacyclics: Consultancy; AstraZeneca: Speakers Bureau; BMS/Celgene/Juno: Consultancy, Research Funding; Genentech: Consultancy; Epizyme: Consultancy; Roche: Consultancy. Ma: Beigene: Research Funding, Speakers Bureau; Juno: Research Funding; AstraZeneca: Honoraria, Research Funding, Speakers Bureau; Loxo: Research Funding; Janssen: Research Funding, Speakers Bureau; Abbvie: Honoraria, Research Funding; TG Therapeutics: Research Funding; Pharmacyclics: Research Funding, Speakers Bureau. Winter: BMS: Other: Husband: Data and Safety Monitoring Board; Agios: Other: Husband: Consultancy; Actinium Pharma: Consultancy; Janssen: Other: Husband: Consultancy; Epizyme: Other: Husband: Data and Safety Monitoring Board; Gilead: Other: Husband: Consultancy; Ariad/Takeda: Other: Husband: Data and Safety Monitoring Board; Karyopharm (Curio Science): Honoraria; Merck: Consultancy, Honoraria, Research Funding; Novartis: Other: Husband: Consultancy, Data and Safety Monitoring Board. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. OffLabel Disclosure: TAK-659 will be discussed for the treatment of DLBCL (not FDA approved for this indication)

Introduction: Approximately 30-35% of patients with classic Hodgkin Lymphoma will prove refractory to frontline therapy or relapse subsequently. Traditional second-line chemotherapy regimens including ifosfamide, carboplatin, and etoposide (ICE) result in complete response rates of ~50%. Achievement of complete metabolic response (CMR) assessed by PET/CT imaging prior to autologous hematopoietic stem cell transplant (AHSCT) predicts favorable progression free survival (PFS) and overall survival (OS). PD-1 blockade is a well-established therapeutic strategy for the treatment of cHL. Pembrolizumab (PEM) is a checkpoint inhibitor targeting PD-1 currently FDA approved as monotherapy in relapsed cHL. We hypothesized that PEM in combination with ICE (PEM-ICE) chemotherapy would be a safe and effective regimen that would yield high CMR rates prior to AHSCT. Methods: This single arm, phase II, multi-institutional clinical trial evaluated the addition of PEM to ICE chemotherapy in AHSCT eligible patients with relapsed and refractory cHL (NCT03077828). The regimen consisted of 21 day cycles of PEM 200 mg IV on day 1 with standard ICE including ifosfamide 5 g/m2 with MESNA as a 24hr continuous infusion on day 2, carboplatin AUC 5 IV (max 800 mg) on day 2, and etoposide 100 mg/m2/day IV on days 1 to 3. Two cycles of PEM-ICE were followed by stem cell mobilization/collection. One cycle of PEM 200 mg IV monotherapy was then administered. Our primary endpoint was the rate of CMR on PET/CT (PET2) imaging defined as a Deauville score of ≤ 3. Images were reviewed centrally. An optional third cycle of PEM-ICE was permitted for patients achieving CMR to allow for appropriate timing of AHSCT. Secondary objectives included clinical outcomes (PFS and OS), safety and tolerability, and transplantation related metrics including ability to collect stem cells and time to engraftment. Results: A total of 42 patients were enrolled with 37 patients evaluable for the primary endpoint. Median age was 34 (19-70) with female predominance (n=27, 64%). 16 patients had primary refractory disease. The CMR rate assessed by PET/CT imaging following 2 cycles of PEM-ICE was 86.5% (95% CI, 71.2-95%), meeting our primary endpoint of improvement over historical outcomes to 70%. The PET2 ORR was 97.3% with 11% PR and 2.7% PD. PET2 scores were Deauville 1 in 45% (n=17), Deauville 2 in 27.0% (n=10), Deauville 3 in 8.1% (n=3), Deauville 4 in 13.5% (n=5), and Deauville 5 in 5.4% (n=2). New areas of PET-positivity in two cases were biopsied showing noncaseating granuloma in one case and EBV but no cHL in another. Five patients received the optional third cycle of PEM-ICE chemotherapy with 35 of the 37 evaluable patients proceeding to AHSCT. Seven patients had radiation as part of the conditioning regimen with an additional 4 patients receiving consolidative radiation following transplant. After a median follow up of 27 months, the median PFS was 26.9 months with survival probability at 24 months of 88.2% (Figure 1). Median OS was not reached with too few events but remained 95.1% at 27 months. The addition of PEM to ICE did not impair stem cell mobilization and all patients successfully collected, with 35 (87%) within 2 apheresis sessions (range 1-7). No patients had engraftment delays or failure. Of the 42 patients, all received at least one dose of PEM and were therefore eligible for toxicity analyses. 34 patients (81%) experienced adverse events (AEs) attributed to PEM and 22 patients (52.3%) had grade 3-4 AEs comprised of cytopenias, elevated AST/ALT, hyponatremia, hypophosphatemia, and fatigue. Five patients had severe AEs attributed to PEM which included anemia, back pain, decreased EF, fever, and thrombocytopenia. There were no significant PEM-related autoimmune events that delayed a patient's treatment on protocol. There were two grade 5 toxicities on the protocol including a patient with cardiac arrest during stem cell collection and a patient with acute respiratory distress syndrome attributed to engraftment syndrome. Both were judged "possibly" related to PEM. Conclusions: Pembrolizumab with ICE chemotherapy is a tolerable and efficacious regimen with high CMR rate as assessed by PET/CT. Despite short follow up, patients had excellent PFS and OS in the post-transplant setting. The results support further investigation of PEM-ICE as second-line treatment for AHSCT eligible patients with relapsed and refractory classical Hodgkin lymphoma. Figure 1 Figure 1. Disclosures Casulo: BMS: Research Funding; Verastem: Research Funding; Genentech: Research Funding; Gilead: Research Funding. Allen: Kyowa Kirin: Consultancy, Honoraria, Research Funding; Daichii Sankyo: Consultancy, Honoraria; Secure Bio: Consultancy, Honoraria. Karmali: Epizyme: Consultancy; AstraZeneca: Speakers Bureau; Roche: Consultancy; Genentech: Consultancy; EUSA: Consultancy; Janssen/Pharmacyclics: Consultancy; Karyopharm: Consultancy; Morphosys: Consultancy, Speakers Bureau; BeiGene: Consultancy, Speakers Bureau; Kite, a Gilead Company: Consultancy, Research Funding, Speakers Bureau; BMS/Celgene/Juno: Consultancy, Research Funding; Takeda: Research Funding. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. Winter: Actinium Pharma: Consultancy; BMS: Other: Husband: Data and Safety Monitoring Board; Karyopharm (Curio Science): Honoraria; Novartis: Other: Husband: Consultancy, Data and Safety Monitoring Board; Merck: Consultancy, Honoraria, Research Funding; Ariad/Takeda: Other: Husband: Data and Safety Monitoring Board; Epizyme: Other: Husband: Data and Safety Monitoring Board; Agios: Other: Husband: Consultancy; Gilead: Other: Husband: Consultancy; Janssen: Other: Husband: Consultancy. OffLabel Disclosure: new combination of study agent with standard of care chemotherapy regimen

BACKGROUND: Maintenance rituximab in MCL has improved survival and supports the exploration of maintenance with novel targeted agents. Ibrutinib is a BTK inhibitor approved for relapsed/refractory MCL. We report the final analysis of safety and efficacy of Ibrutinib maintenance (I-M) as monotherapy following chemo-immunotherapy induction for treatment-naive MCL in a multicenter phase II trial. METHODS: Pts with CR/PR to frontline chemo-immunotherapy (+/- autologous stem cell transplant (autoSCT)) received I-M 560 mg daily for up to 4 years. The primary endpoint was 3-year PFS rate. Secondary endpoints were to determine PR to CR conversions, median OS and the safety profile of I-M. Minimal residual disease (MRD) was measured using an NGS-MRD assay on peripheral blood (detection resolution of 1 cell per million; clonoSEQ®; Adaptive Biotechnologies) prior to and 1, 6 and 18-24 mo(s) after initiation of I-M. RESULTS: 36 pts were enrolled to complete accrual. Median age was 60 years (range 46-90). For induction, most pts were treated with BR (n=17, 47%) or a cytarabine-containing regimen (n=18, 50%). Eighteen (50%) pts underwent autoSCT. Thirty-four (94%) and 2 (6%) had CR and PR as best response to induction respectively, with 1 PR to CR conversion on I-M. At a median follow-up of 47 months, 10 (28%) pts completed a full I-M course, 7 (19%) remain on I-M, 15 (42%) discontinued I-M for treatment related adverse events (TRAEs) and 4 (11%) discontinued I-M for other reasons (PD x 1, secondary malignancies requiring treatment x 2, death cause unknown x 1). Three pts died during I-M, 2 deaths deemed unrelated to I-M (aspiration pneumonia, 2 nd malignancy) and 1 from unknown cause; 1 pt was lost to follow-up. Four pts were treated with rituximab maintenance after stopping I-M prematurely for toxicity without evidence of disease progression prior to or after change in therapy. At the time of data cut-off, MRD was assessed in 22 of 36 pts (available samples) at varying time points (Fig 1) with a dominant clone identified in all 22 pts. Pts were deemed MRD (-) if no sequences were detected at a threshold of 10 -6. Seventeen pts were MRD (-), 4 MRD indeterminate and 1 MRD (+) with radiographic CR after induction; the latter remained MRD (+) at 18 months with CR. All MRD indeterminate pts were MRD (-) when checked after 1 month on I-M. Six pts MRD (-) post-induction became MRD (+) during their I-M course. Of these pts, 2 reverted to MRD (-) with continued I-M; of the remaining 4 pts, 1 had PD and the others maintain stable clinical responses with ongoing I-M though MRD has not been rechecked. 3-year PFS and OS rates were 91% and 94% respectively (Figure 2A, B). PFS was improved in pts who received autoSCT prior to enrollment (Fig 2C, p=0.03) with a trend for improved OS (Figure 2D, p=0.057). MRD did not correlate with PFS (p=0.65) and OS (p=0.45) given few events. Atrial fibrillation/flutter occurred in 10 pts (28%; G1-2 n=7, 19%, G≥3 n = 3, 8%), 8 (22%) with new onset and 2 (6%) with worsening grade. HTN occurred in 20 pts (55%; G1-2 n=13, 33%, G≥3 n = 7, 22%), 15 (42%) with new onset and 5 (14%) with worsening grade. Incidences of both atrial fibrillation/flutter and HTN increased over time with ongoing I-M exposure (Table). Four pts had a 2 nd solid malignancy, 2 while on treatment and 2 after stopping I-M. TRAEs led to permanent dose reductions in 8 (22%) pts, 2 for neutropenia, 2 for fatigue, 2 for myalgias, 1 each for diarrhea and mucositis. Fifteen (42%) pts permanently discontinued I-M, most commonly for atrial fibrillation/flutter (n=8, 22%; n=5, 14% for G1-2). CONCLUSION: I-M 560 mg daily after response to frontline chemo-immunotherapy is feasible in MCL and results in durable PFS and OS. Toxicities including rates of high-grade atrial fibrillation/flutter and HTN are consistent with ibrutinib's known safety profile with increased incidence with longer exposure; discontinuation of I-M for atrial fibrillation/flutter in 22% of pts is higher than expected. Changes in NGS-MRD were noted in a small number of pts during maintenance. Extended follow-up and correlation of changes in MRD with PFS and OS are needed to determine clinical relevance of I-M and MRD status. Further studies evaluating maintenance with next generation BTK inhibitors as alternatives to ibrutinib should be explored to mitigate toxicity. Figure 1 Figure 1. Disclosures Karmali: Takeda: Research Funding; Genentech: Consultancy; Roche: Consultancy; Epizyme: Consultancy; Morphosys: Consultancy, Speakers Bureau; BeiGene: Consultancy, Speakers Bureau; Janssen/Pharmacyclics: Consultancy; BMS/Celgene/Juno: Consultancy, Research Funding; AstraZeneca: Speakers Bureau; Karyopharm: Consultancy; Kite, a Gilead Company: Consultancy, Research Funding, Speakers Bureau; EUSA: Consultancy. Abramson: Seagen Inc.: Research Funding; Allogene Therapeutics: Consultancy; Astra-Zeneca: Consultancy; Incyte Corporation: Consultancy; BeiGene: Consultancy; Kymera: Consultancy; Bluebird Bio: Consultancy; Genmab: Consultancy; EMD Serono: Consultancy; Bristol-Myers Squibb Company: Consultancy, Research Funding; Novartis: Consultancy; Kite Pharma: Consultancy; Morphosys: Consultancy; C4 Therapeutics: Consultancy; AbbVie: Consultancy; Karyopharm: Consultancy; Genentech: Consultancy. Stephens: JUNO: Research Funding; Abbvie: Consultancy; Adaptive: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Innate Pharma: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; AstraZeneca: Consultancy; CSL Behring: Consultancy; Celgene: Consultancy; Mingsight: Research Funding; Arqule: Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Epizyme: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding. Winter: Ariad/Takeda: Other: Husband: Data and Safety Monitoring Board; Actinium Pharma: Consultancy; BMS: Other: Husband: Data and Safety Monitoring Board; Gilead: Other: Husband: Consultancy; Janssen: Other: Husband: Consultancy; Epizyme: Other: Husband: Data and Safety Monitoring Board; Agios: Other: Husband: Consultancy; Novartis: Other: Husband: Consultancy, Data and Safety Monitoring Board; Merck: Consultancy, Honoraria, Research Funding; Karyopharm (Curio Science): Honoraria. Ma: Juno: Research Funding; Beigene: Research Funding, Speakers Bureau; AstraZeneca: Honoraria, Research Funding, Speakers Bureau; Loxo: Research Funding; Janssen: Research Funding, Speakers Bureau; Abbvie: Honoraria, Research Funding; TG Therapeutics: Research Funding; Pharmacyclics: Research Funding, Speakers Bureau. Petrich: Daiichi-Sankyo: Current Employment; Abbvie: Ended employment in the past 24 months. Hochberg: Leuko: Consultancy; Trapelo Health: Consultancy. Kuhr: Adaptive Biotechnologies: Current Employment. Lee: Adaptive Biotechnologies: Current Employment. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. OffLabel Disclosure: We will report on the use of ibrutinib maintenance after front-line induction therapy in MCL.

Background: Anti-CD19 chimeric antigen receptor T-cell therapy (CART) is a highly active therapy for relapsed/refractory (R/R) aggressive B-cell lymphoma. Nonetheless, most patients (pts) ultimately develop progressive disease (PD). There is little guidance on the optimal treatment approach(es) for these pts. We performed a multicenter retrospective analysis with a primary objective to assess treatment patterns and outcomes in pts with R/R aggressive B-cell lymphoma who develop PD after anti-CD19 CARTs. Methods: Pts with aggressive B-cell lymphoma treated with anti-CD19 CART between 2015 and 2020 across 12 US academic medical centers were included. Demographic and clinical characteristics were collected along with CART toxicities and response. Regimens administered as salvage post CART were assessed. Univariate analyses (UVA) were performed to determine impact of demographic and clinical variables on survival outcomes. All p-values were two-tailed. Survival curves were calculated using the Kaplan-Meier method. Results: A total of 400 pts received anti-CD19 CARTs and were included for analysis. For the entire cohort: median PFS and OS from time of CART infusion were 11 months [mo] and 27 mo respectively. On log-rank testing, pts who received ≥3 lines of pre-CART therapy and those with refractory disease pre-CART had significantly worse PFS (p=0.004 & 0.001) and OS (both p With median follow-up 22.4 mo, 190 pts (48%) had PD after CART; demographic and clinical variables of pts with and without PD are detailed in Table 1. Biopsy to confirm PD and assess CD19 status was done in 69 pts (36%) with CD19 negative relapse seen in 11 (16%). Of pts with PD, median PFS and OS from time of PD was 83 days (in pts who received salvage) and 174 days (for all PD pts) respectively. Pts with PD were more likely to have elevated LDH (p=0.001) and extranodal disease (p=0.003) at apheresis. For pts with PD after CART: 125 (65.5%) received further therapies. Pts were more likely to receive salvage therapies if their best response to CART was CR (p=0.026) or PR (p=0.015). Response rates of select first- and second-line therapies and PFS of first line therapies received after CART failure are detailed in figure 1. ORR and CRs were highest for polatuzumab, bendamustine, & rituximab (pola-BR; 73% & 40%), followed by BTK inhibitors (BTKi; 50% & 38%), and bispecific antibodies (bsAb) (50% & 25%). Five of 7 pts who received a BTKi had non-germinal center (GC) cell of origin (COO; 1 unknown COO). On log-rank testing, pts with elevated LDH (p=0.003) at time of apheresis and those with intermediate/high IPI (p=0.013) had inferior PFS with first salvage regimens. Median PFS was highest for pola-BR (4.5 mo, n=14), followed by bsAb (2.5 mo, n=8), lenalidomide +/- anti-CD20 antibody (1.8 mo, n=13), checkpoint inhibitors (CPI; 1.6 mo, n=10), BTKi (1.2 mo, n=8), radiation alone (1.2 mo; n=17), chemotherapy (1.1 mo, n=12), and tafasitamab + lenalidomide (0.9 mo, n=5). Median PFS for all treated pts was 1.8 mo. OS from start of first salvage regimen was highest for CPI (OS 12.4 mo, n=10), followed by pola-BR (8.9 mo, n=14), BTKi (8.8 mo, n=8), lenalidomide +/- anti-CD20 (8.7 mo, n=13), radiation alone (7.1 mo, n =17), bsAb (5.9 mo, n=8), chemotherapy (5.4 mo, n=12), and tafasitamab + lenalidomide (1.2 mo, n=5). 12 pts (6.3%) later received an allogeneic hematopoietic cell transplant (alloHCT). In alloHCT pts at last follow-up, 10 were evaluable for response: 7 had CR and 5 remain in CR. Clinical characteristics of pts who received alloHCT are detailed in table 2. Notably, median age was 59 years (41-68), 1 (8.3%) had a prior alloHCT, and 6 (50%) had prior autologous HCT. The majority had CR or PR as best response to CART (CR n=6, 50%; PR n=3, 25%), and only 1 pt (8.3%) with PD as best response to CART was salvaged with alloHCT. Conclusions: This is the largest reported analysis to date of pts with aggressive B-cell lymphoma who develop PD post-CART. The highest ORRs were with pola-BR, bsAb, and BTKi as first line of salvage. High response rates with BTKi may be attributed to non-GC COO in the majority of treated pts and perhaps a beneficial immunomodulatory effect on previously administered CARTs. AlloHCT remains a potential curative therapy for select pts with over half with durable remission; however, few ultimately received alloHCT. Despite increased use of novel therapies, survival in pts who progress after CART is still dismal warranting more effective therapies. Figure 1 Figure 1. Disclosures Epperla: Genzyme: Honoraria; Karyopharm: Other: Ad Board; Beigene: Speakers Bureau; Verastem: Speakers Bureau. Torka: TG Therapeutics: Membership on an entity's Board of Directors or advisory committees. Hess: ADC Therapeutics: Consultancy; BMS: Speakers Bureau. Cohen: Janssen, Adicet, Astra Zeneca, Genentech, Aptitude Health, Cellectar, Kite/Gilead, Loxo, BeiGene, Adaptive: Consultancy; Genentech, BMS/Celgene, LAM, BioINvent, LOXO, Astra Zeneca, Novartis, M2Gen, Takeda: Research Funding. Ma: Abbvie: Honoraria, Research Funding; Beigene: Research Funding, Speakers Bureau; Loxo: Research Funding; Juno: Research Funding; AstraZeneca: Honoraria, Research Funding, Speakers Bureau; Janssen: Research Funding, Speakers Bureau; TG Therapeutics: Research Funding; Pharmacyclics: Research Funding, Speakers Bureau. Winter: Gilead: Other: Husband: Consultancy; Janssen: Other: Husband: Consultancy; Ariad/Takeda: Other: Husband: Data and Safety Monitoring Board; Epizyme: Other: Husband: Data and Safety Monitoring Board; Agios: Other: Husband: Consultancy; Actinium Pharma: Consultancy; BMS: Other: Husband: Data and Safety Monitoring Board; Merck: Consultancy, Honoraria, Research Funding; Novartis: Other: Husband: Consultancy, Data and Safety Monitoring Board; Karyopharm (Curio Science): Honoraria. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. Danilov: Bayer Oncology: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Honoraria, Research Funding; Rigel Pharm: Honoraria; Takeda Oncology: Research Funding; TG Therapeutics: Consultancy, Research Funding; Abbvie: Consultancy, Honoraria; Beigene: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; SecuraBio: Research Funding; Astra Zeneca: Consultancy, Honoraria, Research Funding; Bristol-Meyers-Squibb: Honoraria, Research Funding; Gilead Sciences: Research Funding. Stephens: Adaptive: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Epizyme: Membership on an entity's Board of Directors or advisory committees; JUNO: Research Funding; Mingsight: Research Funding; CSL Behring: Consultancy; Novartis: Research Funding; Abbvie: Consultancy; AstraZeneca: Consultancy; Arqule: Research Funding; Celgene: Consultancy; Innate Pharma: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding. Shah: Miltenyi Biotec: Consultancy, Honoraria, Research Funding; Umoja: Consultancy; Incyte: Consultancy; Kite: Consultancy; Legend: Consultancy; Epizyme: Consultancy; Lily: Consultancy, Honoraria, Research Funding. Shouse: Beigene Pharmaceuticals: Honoraria; Kite Pharmaceuticals: Speakers Bureau. Barta: Acrotech: Honoraria; Daiichi Sankyo: Honoraria; Seagen: Honoraria; Kyowa Kirin: Honoraria. Karmali: Karyopharm: Consultancy; EUSA: Consultancy; Roche: Consultancy; Janssen/Pharmacyclics: Consultancy; Genentech: Consultancy; Morphosys: Consultancy, Speakers Bureau; Epizyme: Consultancy; Kite, a Gilead Company: Consultancy, Research Funding, Speakers Bureau; BMS/Celgene/Juno: Consultancy, Research Funding; AstraZeneca: Speakers Bureau; Takeda: Research Funding; BeiGene: Consultancy, Speakers Bureau.

Background Patients treated with chronic immunosuppression face a six-fold increase in their cumulative lifetime risk of lymphoma relative to age-matched immunocompetent counterparts. These malignances represent a spectrum of lymphoid and plasmacytic histologies collectively referred to as post-transplant lymphoproliferative disorders (PTLD). Accurate risk-stratification and optimal treatment strategies are unclear given wide histologic and clinical heterogeneity. Current standard-of-care models include immunosuppression reduction and sequential, response-adapted chemoimmunotherapy platforms, however 80% of patients will require chemotherapy exposure. Overall response rates (ORR) are >90%, however relapse is common and serious treatment-related toxicities including infection and allograft rejection pose significant challenges. Several risk-stratification schemes have been proposed to direct initial therapy and predict clinical outcomes, however their external validity has been inconsistent across patient populations. We report here the results of a single-center retrospective study assessing the treatment patterns and outcomes of patients diagnosed with PTLD and provide a risk-assessment profile that may help improve clinical outcomes. Methods Patients with a diagnosis of PTLD were identified by Electronic Medical Records database query. Inclusion criteria were: age ≥ 18 years at the time of diagnosis, confirmation of PTLD by internal pathology review, primary diagnosis from 2008-2018, and receipt of therapy and surveillance care at Northwestern University in Chicago, Illinois, USA. Exploratory univariate analyses were performed using Kaplan-Meier estimates with 95% confidence intervals and log-rank p-values for time-to-event outcomes; significance was set at p < 0.05. Response to treatment and disease progression were classified per provider-specific interpretations of clinical data as assessed by patient chart review. ORR is defined as complete or partial response. Progression-free survival (PFS) is defined as time from diagnosis to disease progression; patients who died before restaging or who were lost to follow-up were censored. Overall survival (OS) is defined as time from diagnosis to death from any cause; patients who were alive at last follow-up were censored. Results A total of 182 patients were identified by database query and 111 patients met our inclusion criteria. Demographics data are provided (Figure 1A). Five-year PFS and OS were 55.7% and 87.2%, respectively (Figure 1B). 92.6% of patients treated with immunosuppression agents underwent dose reduction and 16.8% experienced graft rejection, of which 27.8% required re-transplantation. Exploratory univariate analyses were performed on the following clinical factors: age, LDH, Ann-Arbor Stage, presence of extranodal disease, histologic EBER positivity, ECOG PS, comorbid conditions (type II diabetes, obesity, and coronary artery disease), CNS involvement, transplant type, presence of EBV viremia, and PTLD subtype. Established risk stratification models, including the IPI, R-IPI, Leblond score, Ghobrial score, and PTLD prognostic index, were applied to this cohort. We identified elevated LDH (p=0.04) and IPI score >3 (p=0.015) as predictors of PFS (Figure 1C); elevated LDH (p=0.02) and thoracic allograft transplantation (p=0.03) were predictors of OS (Figure 1D). The PTLD prognostic index significantly predicted PFS (p=0.03) and OS (p=0.013) (Figure 1E). 50.4% received Rituximab monotherapy prior to risk-stratification for combination chemoimmunotherapy; ORR and CR rates with Rituximab monotherapy were 67.9% and 41.1%, respectively. Overall response to Rituximab monotherapy was found to be a significant predictor of PFS (p Conclusions This study represents one of the largest retrospective cohorts of PTLD patients to date. We show that the PTLD prognostic index is the most accurate risk stratification tool in predicting PFS and OS in this patient population and may have utility in guiding therapeutic approaches in PTLD patients. LDH, IPI score, and type of allograft transplantation are significant clinical variables in predicting clinical outcomes. Furthermore, response to Rituximab monotherapy was a significant predictor of PFS; improving frontline outcomes to high-risk patients remains a critical unmet need. Figure Disclosures Winter: Epizyme: Other: DSMB; Delta Fly Pharma: Consultancy; Amgen: Consultancy; CVS/Caremark: Consultancy; Ariad/Takeda: Consultancy; Norvartis: Consultancy, Other: DSMB; Merck: Membership on an entity's Board of Directors or advisory committees, Other: advisory board; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: advisory board. Gordon:Zylem Biosciences: Patents & Royalties: Patents, No Royalties. Karmali:BeiGene: Speakers Bureau; BMS/Celgene/Juno: Honoraria, Other, Research Funding, Speakers Bureau; Gilead/Kite: Honoraria, Other, Research Funding, Speakers Bureau; Takeda: Research Funding; Karyopharm: Honoraria; AstraZeneca: Speakers Bureau. Ma:AbbVie: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; BeiGene: Honoraria, Research Funding, Speakers Bureau; Bioverativ: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Kite: Consultancy, Honoraria; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; Juno: Research Funding; Novartis: Research Funding; TG Therapeutics: Research Funding. Ganger:Mallinkrodt: Consultancy; Gilead: Speakers Bureau. Pro:Verastem Oncology: Research Funding.

Background: Chromosome 9p24.1/PD-L1/PD-L2 genomic copy number alterations (CNAs) including amplifications and copy number gains (CNGs) are predominant features of classic Hodgkin lymphoma (cHL) and lead to overexpression of the programmed death-1 (PD-1) ligands 1 and 2 (PD-L1 and PD-L2). Amplifications and high level CNGs have been associated with advanced stage cHL and inferior treatment outcomes with standard chemotherapy. There are few studies that correlate 9p24.1/PD-L1/PD-L2 amplifications or CNGs with response to PD-1 blockade monotherapy in the frontline setting. We conducted a phase 2 clinical trial of sequential pembrolizumab (PEM) x 3 followed by doxorubicin, vinblastine, dacarbazine (AVD) chemotherapy (4-6 cycles) for newly diagnosed cHL. Interim response to single agent PEM was assessed by PET-CT and by decline in metabolic tumor volume (MTV). Herein, we report the results of correlative studies analyzing 9p24.1 CNAs, PD-1 pathway expression and response to PD-1 blockade. Methods: Pre-treatment diagnostic biopsy specimens were double stained for PD-L1 (E1L3N, XP Cell Signaling) and PAX5, single stained for PD-L2 and pSTAT3, and scored by two expert hematopathologists (QC, LBS) for percentage positive cells and intensity of staining. A modified H score was calculated as the product of staining intensity (0-3) and percentage of positive tumor cells (0-100%), ranging from 0 - 300. Fluorescence in situ hybridization to assess (FISH) chromosome 9p24.1 CNAs was performed by co-hybridizing PD-L1/PD-L2 probes (target) with the centromeric 9 probe (control). In each case, the percentage and magnitude of 9p24.1 CNAs were evaluated. Four FISH categories were defined based on the target: control ratio and the total copy numbers (CNs) of the target per Hodgkin Reed-Sternberg (HRS) cell to include: amplification (ratio≥3, CNs≥ 6), copy number gain (CNGs) (1≤ratio Results: Thirty patients were enrolled from September 2017, through August 1, 2019; 28 had tissue available for FISH analysis and 29 for immunohistochemistry. Response to single agent PEM was PR in 11 (36.7%), near-CMR in 8 (26.7%), and CMR in 11 (36.7%). CMR rate following AVD x 2 was 100%. All patients in this analysis had genomic alterations, although 5 patients did not reach the cut off of 10%. The highest level alteration was amplification in 11 patients (36.7%), copy gain in 7 (23.3%), polysomy in 5 (16.7%) and disomy in 5 (16.7%) (Table 1). The average 9p24.1 copy number per HRS cell was 3.1 (range 2-8.1). Six of 22 examined cases were EBER-positive. There was no evidence of a statistical relationship between response to single agent PEM and 9p24.1 alteration, PD-L1, PD-L2 or STAT3 H-scores, or EBER status. We found PD-L1 H Score tercile differed statistically by FISH category (P=.024, Fisher's Exact Test). Notably, there were no patients with amplification in the lowest tercile. More compelling, we found a positive association between PD-L1 H Score and average 9p24.1 locus copy number (Spearman's ρ=.36, P=.063, Fig 1a) and a negative association between PD-L1 H Score and percent disomic cells (Spearman's ρ= -0.21, P=0.29, Fig 1b) although the statistical significance of these results was limited by the small sample size. Conclusions: Our data is consistent with prior reports indicating a positive association between 9p24.1 genetic alterations and PD-L1 expression. The high response rates observed at all PD ligand levels seen in this clinical study suggests that even low levels of PD ligand expression may be sufficient for response to PD-1 blockade in previously untreated cHL. Disclosures Allen: Bayer:Consultancy, Other;Imbrium:Consultancy, Other;Research to Practice:Speakers Bureau;Clinical Care Options:Speakers Bureau;Curio Sciences:Honoraria.Evens:Merck:Consultancy, Honoraria, Research Funding;Pharmacyclics:Consultancy, Honoraria;Novartis:Consultancy, Honoraria;MorphoSys:Consultancy, Honoraria;Research To Practice:Honoraria, Speakers Bureau;Abbvie:Consultancy, Honoraria;Mylteni:Consultancy, Honoraria;Seattle Genetics:Consultancy, Honoraria, Research Funding;Epizyme:Consultancy, Honoraria, Research Funding.Advani:Celgene, Forty Seven, Inc., Genentech/Roche, Janssen Pharmaceutical, Kura, Merck, Millenium, Pharmacyclics, Regeneron, Seattle Genetics:Research Funding;Astra Zeneca, Bayer Healthcare Pharmaceuticals, Cell Medica, Celgene, Genentech/Roche, Gilead, KitePharma, Kyowa, Portola Pharmaceuticals, Sanofi, Seattle Genetics, Takeda:Consultancy.Pro:Verastem Oncology:Research Funding.Karmali:Takeda:Research Funding;BeiGene:Speakers Bureau;BMS/Celgene/Juno:Honoraria, Other, Research Funding, Speakers Bureau;Karyopharm:Honoraria;AstraZeneca:Speakers Bureau;Gilead/Kite:Honoraria, Other, Research Funding, Speakers Bureau.Gordon:Zylem Biosciences:Patents & Royalties: Patents, No Royalties.Winter:Amgen:Consultancy;Epizyme:Other: DSMB;Norvartis:Consultancy, Other: DSMB;CVS/Caremark:Consultancy;Ariad/Takeda:Consultancy;Delta Fly Pharma:Consultancy;Merck:Membership on an entity's Board of Directors or advisory committees, Other: advisory board;Karyopharm:Membership on an entity's Board of Directors or advisory committees, Other: advisory board.

BACKGROUND: Ibrutinib is a BTK inhibitor approved for relapsed/refractory MCL. We evaluated the safety and efficacy of single-agent ibrutinib maintenance (I-M) following frontline chemo-immunotherapy for MCL in a multicenter phase II trial. Herein, we report preliminary results. METHODS: Patients (Pts) received I-M 560 mg daily for up to 4 years after complete/partial response (CR/PR) to frontline chemo-immunotherapy (+/- autoSCT). The 3-year PFS rate was the primary endpoint. Secondary endpoints were PR to CR conversions, median OS and toxicity. After identifying a trackable clone using archived tissue obtained at diagnosis, minimal residual disease (MRD) was measured using NGS (detection resolution of 1 cell per million; clonoSEQ®; Adaptive Biotechnologies) on peripheral blood at 4 time-points: baseline (after induction but prior to starting I-M) and then at 1, 6 and 18-24 mo(s) after initiation of I-M. RESULTS: 36 pts were enrolled between 7/2014-7/2018. Median age was 60 years (range 46-90). For induction, 17 (47%) received BR, 18 (50%) a cytarabine-containing regimen and 1 (3%) R-CHOP. Eighteen (50%) had autoSCT in CR1. Post-induction +/- autoSCT, 33 (92%) had a CR and 3 (8%) had a PR as best response respectively. One patient converted from PR to CR on I-M. Median f/u was 34.6 months. 5 (14%) pts completed the 4-year I-M course and 15 (42%) remain on I-M (median 31 cycles, range 2-52). Sixteen (44%) pts discontinued I-M early due to: treatment related adverse events (TRAEs; n=12), second malignancies considered unrelated to I-M (n=2), PD (n=1) and death of unknown cause (n=1). Three pts died, 2 deaths deemed unrelated to I-M (aspiration pneumonia, 2nd malignancy) and 1 from unknown cause; 1 pt was lost to follow-up. The most common grade ≥ 3 TRAEs during I-M were neutropenia, HTN, infection, bleeding and atrial fibrillation/flutter (Table 1). TRAEs led to permanent dose reductions in 9 (25%) pts, most commonly for neutropenia (n=3), and I-M discontinuation in 12 (33%), 6 for new onset atrial fibrillation/flutter, 1 each for myalgias, rash, pericardial effusion, mucositis, TIA, subdural hematoma/bleed. Notably, I-M was discontinued in the majority of pts with new onset atrial fibrillation/flutter though not typical of current practice. At the time of data cut-off, MRD was assessed in 21 of 36 pts at varying time points (Figure 1) with remaining samples not yet collected/analyzed. After induction but prior to I-M, 16 pts were confirmed MRD (-), 4 were MRD indeterminate and 1 was MRD (+). Four pts MRD (-) prior to I-M became MRD (+) with follow-up, 2 induced with hyperCVAD, 1 with BR and 1 with R-CHOP + autoSCT prior to I-M; 2 of these pts reverted back to MRD (-) status with ongoing I-M. Of the 2 pts with persistent MRD (+) disease, 1 had clinical progression and the other maintains radiographic CR. Post induction, all MRD indeterminate pts were MRD (-) when checked after 1 month on I-M. The pt who was MRD (+) after front-line treatment (Nordic regimen + autoSCT) remains MRD (+) after 30 cycles of I-M without clinical relapse. MRD correlations with PFS and OS have not yet been performed. CONCLUSION: I-M 560 mg daily is feasible in pts with MCL after response to frontline chemo-immunotherapy. Grade ≥ 3 rates of atrial fibrillation/flutter are consistent with ibrutinib's known safety profile. NGS-based assessments demonstrate that most pts are MRD negative after intensive induction. Longer follow-up and correlation of MRD with PFS and OS are needed to determine the clinical relevance of I-M and MRD status. Disclosures Karmali: BeiGene: Speakers Bureau; AstraZeneca: Speakers Bureau; Karyopharm: Honoraria; Takeda: Research Funding; BMS/Celgene/Juno: Honoraria, Other, Research Funding, Speakers Bureau; Gilead/Kite: Honoraria, Other, Research Funding, Speakers Bureau. Stephens:Arqule: Research Funding; Innate: Consultancy; Juno: Research Funding; Acerta: Research Funding; MingSight: Research Funding; Janssen: Consultancy; Karyopharm: Consultancy, Research Funding; Beigene: Consultancy; Pharmacyclics: Consultancy; Gilead: Research Funding; Verastem: Research Funding. Winter:Norvartis: Consultancy, Other: DSMB; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: advisory board; Epizyme: Other: DSMB; Delta Fly Pharma: Consultancy; Amgen: Consultancy; CVS/Caremark: Consultancy; Ariad/Takeda: Consultancy; Merck: Membership on an entity's Board of Directors or advisory committees, Other: advisory board. Ma:Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; BeiGene: Honoraria, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Research Funding; Bioverativ: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; Juno: Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Kite: Consultancy, Honoraria; TG Therapeutics: Research Funding. Petrich:AbbVie: Current equity holder in publicly-traded company; Daiichi-Sankyo: Current Employment. Hochberg:Intervention Insights: Consultancy; Leuko: Consultancy. Kuhr:Adaptive Biotechnologies: Current Employment. Gordon:Zylem Biosciences: Patents & Royalties: Patents, No Royalties. Pro:Verastem Oncology: Research Funding. OffLabel Disclosure: maintenance ibrutinib after frontline therapy in MCL

BACKGROUND: The human c-MYC oncogene is rearranged or overexpressed in approximately 12% or 37% of aggressive B-cell non-Hodgkin lymphomas (NHL), respectively. Relapses within 18-24 months are observed in more than 50% of these patients when treated with standard chemoimmunotherapy. Ixazomib is an orally bioavailable proteasome inhibitor that is FDA approved for multiple myeloma and has been shown to down-regulate MYC in lymphoma models (Ravi et al., 2016). It has also demonstrated preclinical activity in aggressive NHL, including double-hit (DH) lymphoma. Herein, we report results of a multicenter phase I/II study evaluating the safety and efficacy of induction chemotherapy with DA-EPOCH-R in combination with ixazomib followed by ixazomib maintenance in aggressive MYC-aberrant NHL. METHODS: Adult patients with aggressive MYC-aberrant NHL defined as MYC-overexpression (> 40%) by IHC, MYC-amplification (>4 copies) by FISH, and/or MYC-rearrangement by FISH were eligible. Ixazomib was administered in conjunction with 6 cycles of DA-EPOCH-R. Intrathecal methotrexate prophylaxis was administered using institutional guidelines. Ixazomib was continued as maintenance for up to one year in responders. During phase I, an accelerated titration design was employed to determine the MTD of ixazomib (doses of 2.3 mg, 3 mg or 4 mg) in combination with DA-EPOCH-R. During induction, ixazomib was administered twice per cycle (1 cycle = 21 day), day 1 and day 8 or 15 based on blood counts. For maintenance, ixazomib was dosed at 4 mg weekly. Based on phase I results, 3mg of ixazomib was chosen as the RP2D for phase II. The primary objective was to determine MTD in phase I and to evaluate the efficacy of ixazomib given with DA-EPOCH-R as measured by 12-month PFS rate in phase II. Secondary objectives were to evaluate safety and assess ORR post-induction and OS in all phase I/II patients. RESULTS: Thirty-eight patients were enrolled between 10/2015 and 9/2019 and 36 were evaluable for response. Median age was 63 years (range 31-77) and 27 were male (71%), 86% had advanced stage, 46% had DH or triple hit lymphoma (28% and 18%, respectively), and 89% had an IPI of 2 or higher (Table 1). Twenty-nine (76.3%) patients completed all 6 cycles of induction therapy with DA-EPOCH-R and 25 (65.8%) patients were able to undergo dose escalation of DA-EPOCH-R. Two (5.3%) patients had ixazomib dose reductions during induction and 10 (26.3%) patients had discontinuation of ixazomib during induction. Reasons for early discontinuation during induction included peripheral neuropathy, concomitant comorbidities, progressive disease, and death. Of the 21 (55.3%) patients who received maintenance therapy, 5 (23.8%) had ixazomib dose reductions, and 9 (42.9%) had discontinuation of ixazomib during maintenance. Reasons for early discontinuation during maintenance included peripheral neuropathy, patient preference, and progressive disease. Treatment-related adverse events (TRAEs) of interest occurring in b % 10 % of patients are noted in Table 2. The ORR after induction was 89% with an associated CR rate was 61%. One patient received autologous transplant as consolidation and did not pursue maintenance as a result. Estimated 24-months PFS and OS were 66.9% (95% CI, 50.7% to 88.4%) and 78.7% (95% CI, 65.10% to 95.52%), respectively. Of the 21 patients who received maintenance, sixteen had a CR while 5 had a PR. In those who achieved a PR and went on to receive maintenance, 1 patient converted to CR and 1 maintained a PR with ongoing response at last follow-up. Two patients progressed and 1 has not yet been re-evaluated for response. At a median follow up of 17.6 months (range: 14-19 months), 7 patients had PD. Six patients died, 3 from PD, 1 from respiratory failure, 1 from sepsis, and 1 from natural causes considered unrelated to study drug. CONCLUSION: In this older population with aggressive MYC-aberrant NHL, DA-EPOCH-R induction with adjunctive ixazomib followed by maintenance ixazomib appears to be safe and effective. It is notable that 31% of patients had ixazomib dose reduction or discontinuation during induction and only 55% of patients initiated maintenance, which may have compromised the efficacy of this approach. Exploratory analysis of clinical and histological variables is ongoing and will be presented at the meeting. Improving frontline outcomes for this subset of patients remains a critical unmet need. Disclosures Karmali: Karyopharm: Honoraria; AstraZeneca: Speakers Bureau; BeiGene: Speakers Bureau; Takeda: Research Funding; Gilead/Kite: Honoraria, Other, Research Funding, Speakers Bureau; BMS/Celgene/Juno: Honoraria, Other, Research Funding, Speakers Bureau. Hamadani:Takeda Pharmaceutical Company; Spectrum Pharmaceuticals; Astellas Pharma: Research Funding; ADC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme, AstraZeneca: Speakers Bureau; Janssen R&D; Incyte Corporation; ADC Therapeutics; Celgene Corporation; Pharmacyclics, Omeros, AbGenomics, Verastem, TeneoBio: Consultancy. Gordon:Zylem Biosciences: Patents & Royalties: Patents, No Royalties. Winter:Norvartis: Consultancy, Other: DSMB; Ariad/Takeda: Consultancy; CVS/Caremark: Consultancy; Delta Fly Pharma: Consultancy; Amgen: Consultancy; Epizyme: Other: DSMB; Merck: Membership on an entity's Board of Directors or advisory committees, Other: advisory board; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: advisory board. Ma:TG Therapeutics: Research Funding; Novartis: Research Funding; Juno: Research Funding; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; Kite: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Gilead: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; Bioverativ: Consultancy, Honoraria; BeiGene: Honoraria, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Research Funding. Fenske:Medical College of Wisconsin: Current Employment. Shah:Cell Vault: Research Funding; Miltenyi Biotec: Honoraria, Research Funding; Celgene: Consultancy, Honoraria; Incyte: Consultancy; TG Therapeutics: Consultancy; Verastim: Consultancy; Lily: Consultancy, Honoraria; Kite Pharma: Consultancy, Honoraria. Jagadeesh:Verastem: Membership on an entity's Board of Directors or advisory committees; Debiopharm Group: Research Funding; MEI Pharma: Research Funding; Regeneron: Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding. Klein:Takeda: Membership on an entity's Board of Directors or advisory committees. Petrich:AbbVie: Current equity holder in publicly-traded company; Daiichi-Sankyo: Current Employment. Evens:Epizyme: Consultancy, Honoraria, Research Funding; Merck: Consultancy, Honoraria, Research Funding; Pharmacyclics: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; MorphoSys: Consultancy, Honoraria; Research To Practice: Honoraria, Speakers Bureau; Abbvie: Consultancy, Honoraria; Mylteni: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria, Research Funding. Pro:Verastem Oncology: Research Funding. OffLabel Disclosure: Ixazomib is an orally bioavailable proteasome inhibitor that is FDA approved for multiple myeloma. It has also demonstrated preclinical activity in aggressive NHL, including double-hit (DH) lymphoma.

Introduction: FL is the most common indolent non-Hodgkin lymphoma in the Western world. FL may cause disease-related symptoms, and patients with high-risk disease usually require systemic therapy. BR is commonly used as first-line therapy for high-risk FL, and the addition of bortezomib to a BR backbone has been studied (Evens A et al. Clin Can Res 2020). Little is known about how these therapeutic options impact patients' health-related quality of life (HRQL). To fill this gap, patient-reported outcomes (PROs) were administered to patients enrolled on E2408 to quantify symptom burden and effects of BR versus BVR induction on HRQL. Methods: Patients (n=258) randomized to receive 6 cycles of BR or BVR induction completed PROs assessing neurotoxicity (FACT/GOG-Ntx) at the beginning of each treatment cycle. Additional PROs measuring fatigue (FACT-F), lymphoma-specific concerns (FACT-Lym) and HRQL (Functional Assessment of Cancer Therapy-General; FACT-G) were completed at baseline, mid-treatment (MT; cycle 3/4) and end of induction (EOI; cycle 6). Paired t-test was used to assess PRO score changes from baseline to MT and EOI within BR or BVR group. Two-sample t-test was used to compare change scores between groups at MT and EOI, respectively. Univariate analyses with a linear model identified patient baseline characteristics and clinical factors (age, sex, stage, performance status, # extra nodal sites, FLIPI, GELF, bone marrow involvement, elevated LDH, palpable splenomegaly, B-symptoms, CRIS) associated with PRO change scores from baseline to EOI, adjusting for treatment group. A multivariate model was built with backward variable selection approach for each of the PROs. Results: As shown in Figure 1, compared with baseline, patients randomized to BVR reported significantly worse FACT/GOG-Ntx scores at cycle 4, which continued to end of induction (FACT/GOG-Ntx change scores -2.91 to -3.73; p < 0.001). Neurotoxicity remained stable for patients treated with BR (Ntx change scores -0.02 to -0.55). FACT-Fatigue scores indicated worse fatigue at MT compared to baseline for patients receiving BVR (-2.7, p Univariate analyses among all patients identified older age and the absence of palpable splenomegaly at baseline as associated with worse FACT-Lym, FACT-Fatigue, and FACT-G change scores, signifying less improvement in lymphoma-related symptoms, fatigue and HRQL from baseline to end of induction (p Conclusions: Despite worse treatment-related symptoms throughout induction, the addition of bortezomib was associated with comparable overall HRQL to those treated with BR. Both treatments were associated with a reduction in lymphoma-related symptoms from baseline to end of induction, likely contributing to stable HRQL throughout treatment despite treatment-related symptoms. Findings also suggest that a subgroup of patients, particularly those who are older, may experience fewer improvements in lymphoma-related symptoms. This underscores the potential need for closer monitoring and clinical management of these patients. Collectively, results are likely to be encouraging for patients experiencing lymphoma-related symptoms, for whom the symptom burden associated with treatment may be worth the trade-off given the potential for improved disease-related symptom control. Disclosures Evens: Merck: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; MorphoSys: Consultancy, Honoraria; Research To Practice: Honoraria, Speakers Bureau; Epizyme: Consultancy, Honoraria, Research Funding; Mylteni: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Advani:Celgene, Forty Seven, Inc., Genentech/Roche, Janssen Pharmaceutical, Kura, Merck, Millenium, Pharmacyclics, Regeneron, Seattle Genetics: Research Funding; Astra Zeneca, Bayer Healthcare Pharmaceuticals, Cell Medica, Celgene, Genentech/Roche, Gilead, KitePharma, Kyowa, Portola Pharmaceuticals, Sanofi, Seattle Genetics, Takeda: Consultancy. Ansell:Trillium: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; AI Therapeutics: Research Funding; Takeda: Research Funding; Seattle Genetics: Research Funding; Bristol Myers Squibb: Research Funding; ADC Therapeutics: Research Funding. Winter:Norvartis: Consultancy, Other: DSMB; Ariad/Takeda: Consultancy; CVS/Caremark: Consultancy; Delta Fly Pharma: Consultancy; Amgen: Consultancy; Epizyme: Other: DSMB; Merck: Membership on an entity's Board of Directors or advisory committees, Other: advisory board; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: advisory board. Cella:FACIT.org: Membership on an entity's Board of Directors or advisory committees, Other: President; Astellas: Consultancy, Honoraria; Pled Pharma: Research Funding; Janssen: Research Funding; Clovis: Research Funding; Alexion: Research Funding; Apellis: Consultancy; Pfizer: Consultancy, Research Funding; Novartis: Consultancy; Kiniksa: Consultancy; IDDI: Consultancy; BMS: Consultancy, Research Funding; ASAHI KASEI PHARMA CORP.: Consultancy; Oncoquest: Consultancy; Mei Pharma: Consultancy; Ipsen: Consultancy, Research Funding; Evidera: Consultancy; DSI: Consultancy, Research Funding; BlueNote: Consultancy; Abbvie: Consultancy, Research Funding; PROMIS Health Org: Membership on an entity's Board of Directors or advisory committees, Other. Kahl:ADC Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; BeiGene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche Laboratories Inc: Consultancy; Pharmacyclics LLC: Consultancy; Genentech: Consultancy; Celgene Corporation: Consultancy; AstraZeneca Pharmaceuticals LP: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy; Acerta: Consultancy, Research Funding. Wagner:Celgene Inc.: Membership on an entity's Board of Directors or advisory committees; Connect Multiple Myeloma Registry: Membership on an entity's Board of Directors or advisory committees.

Background: Diffuse large B-cell lymphoma (DLBCL) harbors somatic hypermutation (SHM) in the immunoglobulin heavy chain and light chain variable region genes, IGHV and IGK/LV. Recent studies have revealed that IGV SHM creates neoantigens that activate T-cell responses against B-cell lymphoma. Methods: To determine the clinical relevance of IGV SHM in DLBCL treated with standard immunochemotherapy, we performed next-generation sequencing of the immunoglobulin variable regions and complementarity determining region 3 (CDR3) for 378 patients with de novo DLBCL. The prognostic effects of IGV SHM and ongoing SHM or intra-clonal heterogeneity were analyzed in the training (192 patients), validation (186 patients), and overall DLBCL cohorts. To gain mechanistic insight, we analyzed the predicted IG-derived neoantigens' immunogenicity potential, determined by the major histocompatibility complex-binding affinity and the frequency-of-occurrence of T cell-exposed motifs (TCEMs) in a TCEM repertoire derived from human proteome, microbiome, and pathogen databases. Furthermore, IGV SHM was correlated with molecular characteristics of DLBCL and PD-1/L1 expression in the tumor microenvironment assessed by fluorescent multiplex immunohistochemistry. Results: SHM was commonly found in IGHV and less frequently in IGK/LV. High levels of clonal IGHV SHM (SHMhigh) were associated with prolonged overall survival in DLBCL patients, particularly those without BCL2 or MYC translocation. In contrast, long heavy chain CDR3 length, the presence of IGHV ongoing SHM in DLBCL, and high clonal IGK/LV SHM in germinal center B-cell-like (GCB)-DLBCL were associated with poor prognosis. These prognostic effects were significant in both the training and validation sets. By prediction, the SHMhigh groups harbored more potentially immune-stimulatory neoantigens with high binding affinity and rare TCEMs. PD-1/L1 expression in CD8+ T cells was significantly lower in IGHV SHMhigh than in SHMlow patients with activated B-cell-like DLBCL, whereas PD-1 expression in CD4+ T cells and PD-L1 expression in natural killer cells were higher in IGK/LV SHMhigh than in SHMlow patients with GCB-DLBCL. PD-L1/L2 (9p24.1) amplification was associated with high IGHV SHM and ongoing SHM. Conclusions: These results show for the first time that IGV SHMhigh and ongoing SHM have prognostic effects in DLBCL and potential implications for PD-1/PD-L1 blockade and neoantigen-based immunotherapies.

PD-1/L1 and CTLA-4 blockade immunotherapies have been approved for 13 types of cancers and are being studied in diffuse large B-cell lymphoma (DLBCL), the most common aggressive B-cell lymphoma. However, whether both PD-1 and CTLA-4 checkpoints are active and clinically significant in DLBCL is unknown. Whether PD-1 ligands expressed by tumor cells or by the microenvironment of DLBCL are critical for the PD-1 immune checkpoint is unclear. We performed immunophenotypic profiling for 405 patients with de novo DLBCL using a MultiOmyx immunofluorescence platform and simultaneously quantitated expression/coexpression of 13 immune markers to identify prognostic determinants. In both training and validation cohorts, results demonstrated a central role of the tumor immune microenvironment, and when its functionality was impaired by deficiency in tumor-infiltrating T cells and/or natural killer cells, high PD-1 expression (but not CTLA-4) on CD8+ T cells, or PD-L1 expression on T cells and macrophages, patients had significantly poorer survival after rituximab–CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) immunochemotherapy. In contrast, tumor-cell PD-L2 expression was associated with superior survival, as well as PD-L1+CD20+ cells proximal (indicates interaction) to PD-1+CD8+ T cells in patients with low PD-1+ percentage of CD8+ T cells. Gene-expression profiling results suggested the reversibility of T-cell exhaustion in PD-1+/PD-L1+ patients with unfavorable prognosis and implication of LILRA/B, IDO1, CHI3L1, and SOD2 upregulation in the microenvironment dysfunction with PD-L1 expression. This study comprehensively characterized the DLBCL immune landscape, deciphered the differential roles of various checkpoint components in rituximab–CHOP resistance in DLBCL patients, and suggests targets for PD-1/PD-L1 blockade and combination immunotherapies.

Several non-Hodgkin lymphoma (NHL) subtypes, including diffuse large B-cell lymphoma (DLBCL), variably express CD30. This phase 2, open-label study evaluated the efficacy of brentuximab vedotin, an anti-CD30 antibody-drug conjugate, in relapsed/refractory CD30(+) NHL. This planned subset analysis of B-cell NHLs includes 49 patients with DLBCL and 19 with other B-cell NHLs. Objective response rate was 44% for DLBCL, including 8 (17%) complete remissions (CRs) with a median duration of 16.6 months thus far (range, 2.7 to 22.7+ months). There was no statistical correlation between response and level of CD30 expression; however, all responding patients had quantifiable CD30 by computer-assisted assessment of immunohistochemistry. DLBCL patients were generally refractory to first-line (76%) and most recent therapies (82%), and 44% of these refractory patients responded (15% CRs). Patients with other B-cell lymphomas also responded: 1 CR, 2 partial responses (PRs) of 6 with gray zone, 1 CR of 6 with primary mediastinal B-cell, and 1 CR of 3 with posttransplant lymphoproliferative disorder. Adverse events were consistent with known toxicities. The combination of brentuximab vedotin with rituximab was generally well tolerated and had activity similar to brentuximab vedotin alone. Overall, significant activity with brentuximab vedotin was observed in relapsed/refractory DLBCL, and responses occurred across a range of CD30 expression. This study was registered at www.clinicaltrials.gov as #NCT01421667.

Background: MCL carries a poor overall prognosis despite high response rates to induction chemotherapy. Maintenance strategies have impacted survival in MCL but optimal strategies have yet to be defined. Despite profound activity of ibrutinib, a selective BTK inhibitor, in relapsed/refractory MCL, ibrutinib maintenance (I-M) following induction for treatment-naive MCL has not been explored. We report preliminary results of a multicenter phase II trial assessing efficacy and safety of I-M for MCL after frontline induction. Methods: Patients (pts) with MCL with complete or partial response (CR/PR) to frontline chemo-immunotherapy +/- autologous stem cell transplantation (autoSCT) received I-M 560 mg daily for up to 4 years. The primary objective was 3 year PFS rate with I-M. Secondary objectives were PR to CR conversions, median OS after 4 years and toxicity. Measurable residual disease (MRD) assessments using an NGS-MRD Assay (detection resolution of < 1 cell per million; Adaptive Biotechnologies) on peripheral blood and/or PBMCs were planned at 4 time points: prior to I-M initiation and at 1, 6 and 18-24 mo(s) after initiation of I-M. Results: Accrual is complete (n=36). Median age was 60 (range 46-90), 28 pts (78%) were males, 28 (78%) had advanced stage and 9 (25%) had extranodal disease. 18 (50%), 7 (19%) and 11 (31%) had low vs intermediate vs high risk MIPI respectively. For induction, 17 (47%) received bendamustine-rituximab (BR), 18 (50%) a cytarabine-based regimen, and 1 (3%) R-CHOP. 18 (50%) had autoSCT in CR1 prior to enrollment. 33 (92%) and 3 (8%) had CR and PR with induction respectively with 1 PR to CR conversion on I-M. Median follow-up from initiation of induction therapy was 33 mos. With a median follow-up of 24.5 mos from initiation of I-M, 1 pt had disease progression (PD) and 2 others died, 1 from hepatic cholangiocarcinoma 2 years after I-M discontinuation for toxicity (atrial fibrillation) and 1 from unknown cause. 20/36 (56%) pts remain on I-M (median 24 cycles, range 1-52). Sixteen pts discontinued ibrutinib, including 3 for completion of 4 years of I-M. Of the remaining 13 who discontinued, TRAEs accounted for 10 (77%) and the other 3 were for uterine cancer (n=1), PD (n=1), and death of unknown cause (n=1) (Table 1). Atrial fibrillation/atrial flutter accounted for 50% (n=5) of TRAEs that led to I-M discontinuation. 9 (25%) pts required permanent dose reductions for TRAEs with neutropenia (n=3), myalgias (n=2), and fatigue (n=2) being the most common. Collectively, TRAEs led to dose reductions/ interruptions/ discontinuations in 25 (69%) pts. At time of data cut-off, (July 2019), using a trackable dominant clone identified from tissue at diagnosis, MRD was assessed in 12 patients at varying time points (Figure 1). In these 12 pts, 6 were induced with BR, 5 with a cytarabine-based regimen, and 1 with R-CHOP and 5 were consolidated with autoSCT prior to enrollment. Prior to I-M initiation, 9 pts were MRD (-) and 3 had indeterminate MRD status. Indeterminate results corresponded with total cell counts below the level of detection and quantification with our assay. Those with indeterminate MRD status were confirmed to be MRD (-) with subsequent evaluation after 1 month of I-M. 3 of 12 (25%) pts became MRD (+) on I-M. The first reverted back to MRD (-) status and remains MRD (-) with clinical CR on > 3 years of I-M. The second pt was treated with hyperCVAD with PR prior to I-M. This patient required several dose interruptions for neutropenia just prior to MRD detection with clinical PD leading to discontinuation of therapy after 9 months of I-M. The third pt was treated with R-CHOP + autoSCT with PR prior to I-M and maintains a PR despite MRD conversion on > 2 years of I-M. Further analysis of dynamic changes in dominant and non-dominant clones associated with I-M is ongoing. Conclusions: I-M is feasible in MCL pts who respond to frontline chemo-immunotherapy +/- autoSCT with manageable toxicities consistent with the known safety profile of ibrutinib. Guidelines to discontinue I-M for atrial fibrillation were strictly upheld in this protocol though not typical of current practice. NGS can be used to assess MRD with induction and maintenance therapy and demonstrates that most pts are MRD negative after intensive induction. Longer follow-up, evaluation of dynamic changes in MRD, and PFS and OS data are needed to assess clinical relevance of I-M and importance of MRD status, and may support larger, controlled studies. Disclosures Karmali: Gilead/Kite; Juno/Celgene: Consultancy, Speakers Bureau; Takeda, BMS: Other: Research Funding to Institution; Astrazeneca: Speakers Bureau. Abramson:AbbVie Inc, Amgen Inc, Bayer HealthCare Pharmaceuticals, Celgene Corporation, EMD Serono Inc, Genentech, Gilead Sciences Inc, Janssen Biotech Inc, Juno Therapeutics, a Celgene Company, Karyopharm Therapeutics, Kite Pharma Inc, Merck, Novartis, Seattle Gen: Consultancy. Stephens:Karyopharm: Research Funding; Gilead: Research Funding; Acerta: Research Funding. Winter:Merck: Consultancy, Research Funding. Ma:Genentech: Consultancy; Gilead: Research Funding; Astra Zeneca: Consultancy, Research Funding, Speakers Bureau; Acerta: Research Funding; Abbvie: Research Funding; Incyte: Research Funding; Janssen: Consultancy, Speakers Bureau; Kite: Consultancy; Juno: Research Funding; Xeme: Research Funding; Pharmacyclics: Consultancy, Research Funding, Speakers Bureau; Beigene: Research Funding; Bioverativ: Consultancy; Novartis: Research Funding. Petrich:Abbvie: Employment, Equity Ownership. Kuhr:Adaptive Biotechnologies: Employment, Other: shareholder. Gordon:Zylem LLC: Other: co-founder; research in nanoparticles in cancer; Bayer: Other: Advisory Board; Juno/Celgene: Other: Advisory Board, Research Funding; Gilead: Other: Advisory Board. Pro:Takeda: Consultancy, Honoraria, Other: Travel Expenses; Celgene: Consultancy, Honoraria; Kyowa Hakka Kirin: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria, Other: Travel Expenses, Research Funding. OffLabel Disclosure: We will discuss results of our trial looking at ibrutinib maintenance in frontline MCL

Background: Pembrolizumab (PEM), an anti-PD-1 antibody is approved for the treatment of relapsed/refractory cHL based on results of a pivotal trial demonstrating an overall response rate (ORR) of 69% and 22% complete response (CR) rate. To investigate the impact of PEM monotherapy in previously untreated patients (pts), we conducted a phase 2 clinical trial of sequential PEM followed by AVD chemotherapy for untreated cHL. Herein, we report the primary analysis of response (PET2) to single agent PEM in the frontline setting and the results of interim FDG18-FDG PET-CT (PET3) following AVD x 2. Methods: Pts > 18 years of age with newly diagnosed cHL stages I-IV, including early stage pts with at least 1 risk factor according to NCCN criteria, were eligible. Pts were treated sequentially with 3 cycles of PEM at 200 mg every 3 weeks followed by an interim PET-CT (PET2) for primary analysis. Subsequently, pts received 4-6 cycles of AVD chemotherapy based on initial stage, with PET-CT's repeated after 2 cycles of AVD and at the end of therapy. There was no consolidative radiotherapy. Response to single agent PEM was assessed by Lugano criteria and decline in total metabolic tumor volume (TMV). We hypothesized that PEM monotherapy prior to AVD would result in a CR rate of 50% and would reduce the frequency of PET-positivity on the interim PET (PET3) following 2 cycles of AVD compared to prior reports. Results: Thirty pts enrolled from September 2017- March 2019 with a data cutoff of June 14, 2019. The median age of participants was 30 (range, 21-77), and 4 pts were ages >60. Eleven were male, and the majority (83%) were Caucasian. Twelve pts had early unfavorable disease (6 each with elevated ESR, B-symptoms, and bulky mediastinal masses). Eighteen pts had advanced stage disease (5 Stage 3, 13 Stage 4; IPS score 3 -4 in 7, 1-2 in 10). Adverse risk factors for all 30 pts included bulky disease or large mediastinal mass (n=12), B-symptoms (n=14) and extranodal disease (n=16). Overall therapy was well tolerated and most adverse events were grade 1-2. Related events of any grade included hypertension (n=10), rash (n=9), anemia (n=8), infusion reactions (n=5), elevated liver function tests (n=5), arthralgias (n=4) and hypo- or hyperthyroidism (n=3). Grade 3 and 4 events (whether or not judged to be related) were as follows Gr3: lymphopenia (n=4), febrile neutropenia (n=3), neutropenia (n=3), hypertension (n=2), diarrhea (n=1), hyperglycemia (n=1), and hyponatremia (n=1); Gr 4: neutropenia (n=10); transaminitis (n=1); sepsis (n=1). The only Grade 3 or 4 immune-related adverse event was the one grade 4 transaminitis that resolved with steroid administration and a delay in therapy. Eleven of 30 pts achieved CR (37%; Deauville 1-3) following initial PEM monotherapy including three with large mediastinal masses. Four additional patients with bulky disease and four others had major reductions in disease following PEM monotherapy, but did not achieve CR by Lugano criteria (Fig 1A). To better characterize the depth of response, we quantitated the decline in total metabolic tumor volume (TMV) (Fig 1B). Eight of the 17 pts with < CR to PEM monotherapy for whom TMV could be analyzed had > 90% reduction in TMV. A single pt had an atypical response with clearance of original disease sites, but development of new sites that resolved after two cycles of AVD. Across all pts, the CR (Deauville 1-3) rate following 2 cycles of AVD, was 100%. Median follow up is 6.5 (range: 1 - 12) months among those who have completed therapy. No pt has required a change in treatment, relapsed, or progressed, with progression-free and overall survival rates both at 100%. Conclusion: Although the study did not meet its primary endpoint, our data demonstrate that 3 cycles of PEM is highly active in pts with newly diagnosed early unfavorable or advanced stage cHL. PEM monotherapy resulted in > 90% reduction in TMV in the majority of pts, and when followed by AVD x's 2, CR in 100%. No pts have experienced progression or change of therapy to date and treatment was overall very well tolerated. This radiotherapy- and bleomycin-free approach warrants further investigation in larger trials to confirm response rates and assess efficacy compared with other novel combinations in the frontline setting. Disclosures Pro: Takeda: Consultancy, Honoraria, Other: Travel Expenses; Celgene: Consultancy, Honoraria; Kyowa Hakka Kirin: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria, Other: Travel Expenses, Research Funding. Karmali:Gilead/Kite; Juno/Celgene: Consultancy, Speakers Bureau; Takeda, BMS: Other: Research Funding to Institution; Astrazeneca: Speakers Bureau. Gordon:Gilead: Other: Advisory Board; Juno/Celgene: Other: Advisory Board, Research Funding; Zylem LLC: Other: co-founder; research in nanoparticles in cancer; Bayer: Other: Advisory Board. Winter:Merck: Consultancy, Research Funding.

Background: Immunocompromised patients (pts) face an approximate 6-fold increase in lifetime risk of lymphoid malignancies compared with immunocompetent counterparts. Additionally, up to 80% of post-transplant lymphoproliferative disease (PTLD) cases are driven by EBV-associated mechanisms of tumorigenesis. Approximately 70% will express CD30 and over 80% will express CD20. Recent studies of chemoimmunotherapy (CIT) have reported median overall survival (OS) of 2-4 years and treatment-related mortality (TRM) rates of 13-50%. Moreover, solid organ transplant (SOT) pts are at significant risk of graft rejection when CIT is employed, possibly due to "off target" depletion of regulatory T-cell populations. R monotherapy induction, followed by response-stratified use of CIT, has been evaluated (Trappe, et al, JCO, 2016). However, ~75% of pts had an inadequate response to R alone and required subsequent CIT; 2-yr OS for the population as a whole was ~70%. BV is an anti-CD30 antibody-drug conjugate that received accelerated FDA approval for previously untreated CD30+ T-cell lymphoma and Hodgkin lymphoma. We hypothesized that a combination of BV and R would yield improved breadth and depth of response compared with R monotherapy induction, would spare pts subsequent exposure to CIT, and result in favorable OS. Methods: We report here results of a phase I/II multicenter study investigating the efficacy and safety of BV+R as frontline therapy in pts diagnosed with immunosuppression-associated CD30+ and/or EBV+ lymphoid malignancies. Induction consisted of R 375 mg/m2 given days 1, 8, 15, 22 and BV 1.2 mg/kg given days 1, 8, 15, of a 28-day cycle, followed by restaging. Those with progression were removed from study. Pts with stable disease were offered study discontinuation or completion of one consolidation cycle followed by repeat disease assessment. Pts with partial response or complete response (CR) could receive either consolidation followed by maintenance therapy (MT) or move directly to MT without consolidation. Consolidation was identical to induction dosing; MT consisted of BV 1.8 mg/kg every 3 weeks and R 375 mg/m2 every 6 weeks for up to 1 year of therapy. Toxicity was defined using CTCAE 4.0 and response (Cheson, 2007) was assessed at the end of induction, consolidation (if given), and after cycles 4 and 7 of BV. Results: A total of 22 pts were entered in the trial. Toxicity and response data are available for 20 pts. Median age was 67 years (range, 30-79) and 14 pts (64%) were male (range, 30-79 years). Fourteen pts (64%) had received either a SOT or hematopoietic allograft requiring immunosuppression, 3 pts required immunosuppression for underlying rheumatologic conditions, and 3 pts were found to have EBV-associated lymphoid malignancies in the absence of iatrogenic immunosuppression (Table 1). Overall response rate was 70%, including a CR rate of 60%. With median follow-up of 26.1 month, the probability of progression-free survival at 1 year was 75.2% and 67.6% at 3 years (Fig 1). Probability of OS was 89.2% at both 1-year and 3-year follow-up (Fig 1). Median time to best response was 28 days. Three pts withdrew consent after induction, 2 pts died (1 death related to treatment), and 1 patient was lost to follow-up. Seven pts (31%) required dose adjustments or delay of medication administration during induction therapy and 45% required discontinuation of therapy due to toxicity within 1 year. The most frequent grade 3/4 toxicities were peripheral neuropathy, neutropenia, lymphopenia, and pancreatitis. The most frequent adverse events of any grade were fatigue, nausea, abdominal pain, pancytopenia, and peripheral neuropathy (Table 2). Conclusions: The combination of BV + R had an acceptable safety profile and appeared effective in achieving early remissions when used as frontline therapy for PTLD and other immunosuppression-related lymphomas. Specifically, over half of pts achieved CR, and 75% have been spared exposure to multi-agent cytotoxic chemotherapy. Furthermore, survival and PFS data were encouraging compared with historical controls. However, nearly half of pts discontinued therapy within 1 year due to toxicity suggesting poor long-term tolerance of the regimen and that earlier cessation of therapy may be warranted. Further studies are needed to confirm these efficacy results and to determine optimal BV+R dosing regimens and durations. Disclosures Pro: Seattle Genetics: Consultancy, Honoraria, Other: Travel Expenses, Research Funding; Takeda: Consultancy, Honoraria, Other: Travel Expenses; Celgene: Consultancy, Honoraria; Kyowa Hakka Kirin: Consultancy, Honoraria. Gordon:Gilead: Other: Advisory Board; Bayer: Other: Advisory Board; Juno/Celgene: Other: Advisory Board, Research Funding; Zylem LLC: Other: co-founder; research in nanoparticles in cancer. Karmali:Gilead/Kite; Juno/Celgene: Consultancy, Speakers Bureau; Astrazeneca: Speakers Bureau; Takeda, BMS: Other: Research Funding to Institution. Winter:Merck: Consultancy, Research Funding. Ma:Astra Zeneca: Consultancy, Research Funding, Speakers Bureau; Xeme: Research Funding; Bioverativ: Consultancy; Beigene: Research Funding; Pharmacyclics: Consultancy, Research Funding, Speakers Bureau; Kite: Consultancy; Janssen: Consultancy, Speakers Bureau; Genentech: Consultancy; Abbvie: Research Funding; Incyte: Research Funding; Juno: Research Funding; Acerta: Research Funding; Gilead: Research Funding; Novartis: Research Funding. Behdad:Pfizer: Other: Speaker; Thermo Fisher: Membership on an entity's Board of Directors or advisory committees; Loxo-Bayer: Membership on an entity's Board of Directors or advisory committees. Petrich:AbbVie: Employment, Equity Ownership. Smith:Portola Pharmaceuticals: Research Funding.

Background: Despite excellent outcomes in the front-line management of classical Hodgkin lymphoma (cHL), patients with relapsed or refractory disease typically undergo second-line cytotoxic chemotherapy before proceeding to consolidation with autologous hematopoietic stem cell transplant (autoHSCT). Pre-transplant F18-FDG-PET imaging is a well-established predictor of outcomes following autoHSCT; a complete metabolic response (CMR) to second-line therapy defined as a Deauville score 1-3 predicts a favorable outcome and is a requirement for transplant at many centers. The PD-1 pathway plays an important role in the pathogenesis of cHL and checkpoint inhibition with agents including PEM and nivolumab have shown efficacy as monotherapy in heavily pretreated disease. We hypothesized that the addition of PEM to ICE (ifosfamide, carboplatin, and etoposide) chemotherapy will increase the rate of CMR by PET-CT prior to autoHSCT without impairing the mobilization of peripheral blood progenitor cells (PBPC) or engraftment. Here we present interim safety and toxicity data from this ongoing trial (NCT03077828) including the yields of PBPC mobilization and engraftment. Methods: Enrollment criteria include patients age >18 years medically fit for autoHSCT with relapsed/refractory cHL and excludes those with prior PD-1 inhibitor exposure, CNS involvement, more than 2 prior regimens or history of autoimmune disease. Patients are treated with 2 cycles of PEM 200 mg IV on day 1 in combination with ICE chemotherapy (ifosfamide 5000 mg/m2 day 2 CIV over 24hr, carboplatin AUC 5 IV day 2, etoposide 100 mg/m2 IV days 1-3) on a Q21 day cycle. PBPC mobilization and harvest are performed per institutional protocol on recovery post-cycle #2. A cycle of PEM 200 mg IV is then administered as monotherapy followed by response assessment with PET-CT. Patients with Deauville scores ≤3 proceed to autoHSCT per institutional protocol. A third cycle of PEM+ICE is optional following the PET-CT assessment. Neither the conditioning regimen nor management during transplantation is dictated by the protocol. Results: As of July 2019, 23 of 40 planned patients have evaluable safety and toxicity data. One patient had inconclusive pathology and was removed from study after one cycle of PEM-ICE but is included for this report. The median age was 32 (range 19-62) and 17 of 23 patients were females (74%). 8 patients were refractory to first-line therapy, and 9 relapsed within one year of treatment. 19 patients had received ABVD. Following protocol directed therapy, all but one patient had successful mobilization and collection; one had a severe allergic reaction to filgrastim and underwent bone marrow harvest instead. 16 patients collected in a single day of apheresis; the remainder collected within 4 days. The median number of stem cells harvested was 12.6 x 106 CD34+ cells/kg (range 4.2 - 46.1 x 106/kg). 3 patients underwent the 3rd cycle of PEM + ICE chemotherapy. 3 patients had Deauville scores >3 on FDG-PET response assessment; two had biopsies showing only benign processes and proceeded to transplant. Following stem cell reinfusion, all patients successfully engrafted, with a median time to absolute neutrophil and platelet recovery of 11 days (range: 9 - 24) and 12 days (range: 9 - 23), respectively. The combination of PEM + ICE chemotherapy was well tolerated. There were no reports of pneumonitis, colitis, hepatitis, or endocrinopathies. The most common toxicities were cytopenias, mucositis, diarrhea and febrile neutropenia. A single death on protocol was deemed secondary to advanced cardiovascular disease discovered mid-treatment during the patient's pre-transplant assessment. There was no clinical evidence to suggest an inflammatory process resulting in the cardiac arrest. Conclusions: The combination of PEM with ICE chemotherapy in relapsed / refractory cHL appears tolerable and safe. We found no significant hindrance to peripheral blood stem cell harvest and PEM- related AEs were uncommon. Additionally, pre-treatment with a checkpoint inhibitor prior to autoHSCT appears safe thus far and does not appear to delay engraftment. Disclosures Casulo: Celgene: Research Funding; Gilead: Honoraria, Other: Travel, accommodation, expenses; Roche: Other: Travel, accommodation, expenses. Karmali:Takeda, BMS: Other: Research Funding to Institution; Gilead/Kite; Juno/Celgene: Consultancy, Speakers Bureau; Astrazeneca: Speakers Bureau. Pro:Celgene: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Other: Travel Expenses; Kyowa Hakka Kirin: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria, Other: Travel Expenses, Research Funding. Mehta:Millennium/Takeda, Celgene; stock in Celgene, Bristol-Myers Squibb and Bluebird: Speakers Bureau. Gordon:Bayer: Other: Advisory Board; Juno/Celgene: Other: Advisory Board, Research Funding; Gilead: Other: Advisory Board; Zylem LLC: Other: co-founder; research in nanoparticles in cancer. Winter:Merck: Consultancy, Research Funding.

Introduction: RNA expression profiling using Next Generation Sequencing (NGS) provides important and reproducible information on expression levels of various genes. We studied the expression levels of MYC and BCL2 in patients with diffuse large B-Cell lymphoma (DLBCL) using NGS targeted RNA sequencing. We correlated levels of expression of these genes with outcome. Methods: RNA extracted from 441 FFPE samples with DLBC lymphoma and sequenced targeting 1408 genes. The RNA sequencing is based on hybrid capture and the number of reads ranged from 5 to 10 million. RNA quantification was performed using Cufflinks. The RNA levels were normalized to PAX5 mRNA levels. Of these cases, 380 were subclassified as ABC or GCB using expression profiling. The rest were classified as "undetermined", therefore were not included in further analysis. All patients were treated with R-CHOP. Results: The expression of MYC and BCL2 mRNA was slightly higher in ABC as compared with GCB (P=0.01 and P=0.02, respectively). However, in the GCB subtype, patients with MYC expression above the median showed significantly shorter survival as compared with those below the median (P=0.0007, Log-rank test). In contrast, there was no significant difference in survival using median of MYC expression as cutoff in patients classified as ABC subtype (P=0.38). Using upper 15% cut-off point for BCL2 mRNA expression, GCB patients with high BCL2 expression had significantly shorter survival (P=0.005). In contrast, there was no significant difference in survival between high and low BCL2 expression groups in the ABC subtype (P=0.1). When both MYC and BCL2 are considered, patients with high expression of both BCL2 and MYC (double-RNA expression) had significantly shorter survival as compared with patients with low expression of both MYC and BCL2 (P=0.0009) when both GCB and ABC groups are considered. Patients with high BCL2 expression also had poor survival similar to those double-RNA expression. Considering only patients with GCB, high expressor of both MYC and BCL2 had significantly worse outcome (P=0.0015) as compared with low expressors of both MYC and BCL2, but patients with high BCL2 also had significantly poor outcome as compared to low expressor of both MYC and BCL2 (P=0.0005). In contrast, there was no difference in survival for high or low MYC and BCL2 expressor in the ABC group. Conclusion: The data support the concept that in DLBCL, MYC and BCL2 mRNA expression levels are clinically relevant in GCB, but not ABC subtype. Furthermore, targeted RNA sequencing might provide a reliable and practical objective approach for the subclassification of DLBCL and determining double-RNA expression lymphoma. Figure Disclosures Albitar: Genomic Testing Cooperative: Employment, Equity Ownership. Tam:Takeda: Consultancy; Paragon Genomics: Consultancy. Hsi:Abbvie: Research Funding; Eli Lilly: Research Funding; Cleveland Clinic&Abbvie Biotherapeutics Inc: Patents & Royalties: US8,603,477 B2; Jazz: Consultancy. Piris:Calgene: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jansen: Membership on an entity's Board of Directors or advisory committees, Other: Lecture Fees; Nanostring: Membership on an entity's Board of Directors or advisory committees; Kyowa Kirin: Membership on an entity's Board of Directors or advisory committees; Kura: Research Funding; Millenium/Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Lecture Fees, Research Funding. Kantarjian:Immunogen: Research Funding; BMS: Research Funding; Cyclacel: Research Funding; Pfizer: Honoraria, Research Funding; Agios: Honoraria, Research Funding; Ariad: Research Funding; Amgen: Honoraria, Research Funding; Takeda: Honoraria; AbbVie: Honoraria, Research Funding; Astex: Research Funding; Jazz Pharma: Research Funding; Novartis: Research Funding; Actinium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Research Funding.

Contains fulltext : 171804.pdf (Publisher’s version ) (Closed access) CD37 (tetraspanin TSPAN26) is a B-cell surface antigen widely expressed on mature B cells. CD37 is involved in immune regulation and tumor suppression but its function has not been fully elucidated. We assessed CD37 expression in de novo diffuse large B-cell lymphoma (DLBCL), and investigated its clinical and biologic significance in 773 patients treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) and 231 patients treated with CHOP. We found that CD37 loss (CD37-) in approximately 60% of DLBCL patients showed significantly decreased survival after R-CHOP treatment, independent of the International Prognostic Index (IPI), germinal center B-cell-like (GCB)/activated B-cell-like (ABC) cell of origin, nodal/extranodal primary origin, and the prognostic factors associated with CD37-, including TP53 mutation, NF-kappaBhigh, Mychigh, phosphorylated STAT3high, survivinhigh, p63-, and BCL6 translocation. CD37 positivity predicted superior survival, abolishing the prognostic impact of high IPI and above biomarkers in GCB-DLBCL but not in ABC-DLBCL. Combining risk scores for CD37- status and ABC cell of origin with the IPI, defined as molecularly adjusted IPI for R-CHOP (M-IPI-R), or IPI plus immunohistochemistry (IHC; IPI+IHC) for CD37, Myc, and Bcl-2, significantly improved risk prediction over IPI alone. Gene expression profiling suggested that decreased CD20 and increased PD-1 levels in CD37- DLBCL, ICOSLG upregulation in CD37+ GCB-DLBCL, and CD37 functions during R-CHOP treatment underlie the pivotal role of CD37 status in clinical outcomes. In conclusion, CD37 is a critical determinant of R-CHOP outcome in DLBCL especially in GCB-DLBCL, representing its importance for optimal rituximab action and sustained immune responses. The combined molecular and clinical prognostic indices, M-IPI-R and IPI+IHC, have remarkable predictive values in R-CHOP-treated DLBCL.

γδ T-cell large granular lymphocytic (T-LGL) leukemia of the CD4–/CD8– subtype is rare, and data are limited in the literature. This study evaluated the clinical, morphologic, immunophenotypic, and molecular cytogenetic features of 7 cases of CD4–/CD8– γδ T-LGL leukemia. Although this variant shares several clinical and morphologic features with the more common T-LGL leukemias, the incidences of autoimmune hemolytic anemia and pure red cell aplasia are higher. Another striking feature observed in our study was the lack of increased large granular lymphocytes in the peripheral blood in the majority of cases despite prominent bone marrow or splenic involvement. CD4–/CD8– γδ T-LGL leukemia also displays an immunophenotype and pattern of splenic involvement overlapping with hepatosplenic T-cell lymphoma. Clinically, this variant of T-LGL leukemia shows an overall indolent course, but treatment is often required in the initial stages of the disease. Awareness of these features is important for early recognition and accurate diagnosis of patients with CD4–/CD8– γδ T-LGL leukemia.

Background: Pembrolizumab (PEM), a PD-1 inhibitor, is US FDA approved for the treatment of relapsed/refractory cHL based on results of a pivotal trial demonstrating an overall response rate of 69% and complete response (CR) rate of 22%. We hypothesized that PEM monotherapy would result in a higher CR rate (50%) in previously untreated patients owing to greater immunocompetence. Consequently, we initiated a phase 2 clinical trial of upfront sequential PEM and AVD (Adriamycin, Vinblastine, Dacarbazine) chemotherapy. While several of the initial patients had dramatic responses to PEM x's 3 on PET2, they only met Lugano criteria for partial responses. In an attempt to better reflect and quantify the response to checkpoint inhibition, we amended our protocol to include additional analysis of metabolic tumor volume (MTV) and total lesion glycolysis (TLG) which have been investigated as predictors of response in cHL and DLBCL. Herein, we report an interim analysis of toxicity and efficacy, measured by Deauville score, MTV and TLG in the first 13 patients to complete PEM monotherapy. Methods: Patients ≥ 18 years of age with newly diagnosed cHL stages I-IV, including unfavorable early stage disease with at least one risk factor according to the NCCN criteria, were eligible. Patients had a pre-therapy PET-CT, followed by 3 cycles of PEM at 200 mg every 3 weeks and interim PET-CT (PET2) after single agent PEM for primary analysis. Subsequently, patients received 4-6 cycles of AVD chemotherapy based on initial stage. MTV representing the total volume of the metabolically active tumor in a volume of interest (VOI) was calculated using the fixed 41% SUVmax threshold corresponding to the dimensions of the tumor. TLG, combining the volumetric and metabolic information of FDG-PET, was calculated by multiplying the SUVmean of the segmented VOI and the MTV. These measurements were performed using SyngoVia software, Multi-foci segmentation tool (Siemens). Blinded central review of the visually assessed Deauville score was performed, and if different from the report by one of four nuclear medicine radiologists, a second central review was performed to adjudicate. Correlative studies include serum and biopsy samples pre/post PEM to assess immune biomarkers of response. Results: Fifteen patients were enrolled from September 2017, through a data cut off of July 10, 2018, at Northwestern University. Thirteen patients have completed lead-in PEM monotherapy and have undergone PET2. Median age was 30 years (range, 23-77). Eight patients had unfavorable early stage disease and 7 had advanced stage. Early stage risk factors included bulky disease (n=8), B-symptoms (n=5), and elevated ESR (n=5). Overall, therapy was well tolerated. Grade 3 events included lymphopenia (n=1) and diarrhea (n=1). Only one grade 4 immune-related adverse event (transaminitis) occurred, which resolved with steroid therapy and a delay in therapy. PET2 was scored as Deauville 2 or 3 in six cases including three with large mediastinal masses, and as D 4 or 5 in 7 cases with residual activity (Figure 1). PET2 MTV and TLG could be calculated for 12 of 13 cases, (MTV: 42 - 774 cm2, median 134 cm2; TLG: 257 - 5924; median 814). All 12 patients who completed a subsequent scan (PET3) after 2 cycles of AVD are now in a metabolic CR (Deauville 1-3), including all 7 cases with residual activity after PET2. Conclusion: These interim data suggest that upfront PEM x's 3 is highly active in previously untreated cHL. PEM monotherapy resulted in complete metabolic responses in some patients including those with large mediastinal masses, and near complete responses, best represented by the decline in MTV and TLG compared with Deauville scores or Lugano criteria. Our preliminary data suggest that MTV and TLG are useful additional interim indicators of biologic activity when assessing response after PD-1 inhibitor therapy. Disclosures Allen: Merck: Research Funding; Bayer: Consultancy. Evens:Bayer: Consultancy; Janssen: Consultancy; Affimed: Consultancy; Novartis: Consultancy; Tesaro: Research Funding; Abbvie: Consultancy; Seattle Genetics, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Acerta: Consultancy; Pharmacyclics International DMC: Membership on an entity's Board of Directors or advisory committees. Pro:kiowa: Honoraria; Takeda Pharmaceuticals: Honoraria, Other: Travel expenses; portola: Honoraria; Seattle Genetics: Consultancy, Other: Travel expenses, Research Funding. Advani:Millenium: Other: Institutional Research Support; Merck: Other: Institutional Research Support; Kura: Other: Institutional Research Support; Agensys: Other: Institutional Research Support; Takeda: Other: Consultancy/Advisory Role; Roche/Genentech: Other: Consultancy/Advisory Role, Institutional Research Support; Pharmacyclics: Other: Institutional Research Support; Cell Medica: Other: Consultancy/Advisory Role; Kyowa: Other: Consulting/Advisory Role; Janssen Pharmaceutical: Other: Institutional Research Support; Autolus: Other: Consultancy/Advisory Role; Regeneron Pharmaceuticals, Inc.: Other: Institutional Research Support; Seattle Genetics: Other: Consultancy/Advisory role, Institutional Research Support; Bayer Healthcare Pharmaceuticals: Other: Consultancy/Advisory Role; AstraZeneca: Other: Consultancy/Advisory Role; Bristol Myers Squibb: Other: Consultancy/Advisory role and Institutional Research Support; Forty Seven, Inc: Other: Institutional Research Support; Celgene: Other: Institutional Research Support; Gilead/Kite: Other: Consultancy/Advisory Role; Infinity: Other: Institutional Research Support. Winter:Merck: Honoraria, Research Funding.

Radioimmunotherapy (RIT) has proved to be a safe and effective treatment for patients with relapsed or refractory indolent non-Hodgkin lymphoma (NHL) including rituximab-refractory follicular lymphoma. Further, FDA approval was recently granted for use in newly diagnosed follicular lymphoma as consolidative therapy immediately following induction chemotherapy. We detail herein the scope of clinical studies performed in relapsed/refractory and newly diagnosed indolent lymphoma and summarize the associated safety data. In addition, we discuss new applications of RIT that have been investigated in a variety of clinical scenarios (e.g. single-agent and sequential therapy in aggressive NHLs and as a component of stem cell transplant conditioning). The wide array of RIT-based studies have yielded encouraging data, although randomized controlled trials will be needed to prove superiority over conventional therapy. Novel therapeutic RIT-based strategies that continue to be explored include radiation-enhancing agents combined with RIT, pre-targeting, RIT fractionation, as well as the integration of new humanized antibodies. The field of RIT continues to evolve scientifically and grow clinically. A reappraisal of prior data and examination of recently published and ongoing studies will be important in recognizing the potential benefit of RIT in the treatment of NHL.

We evaluated the efficacy and safety of patient-specific immunotherapy with mitumprotimut-T idiotype keyhole limpet hemocyanin and granulocyte-monocyte colony-stimulating factor (GM-CSF) following rituximab in patients with follicular B-cell lymphoma. Patients with previously untreated or relapsed/refractory CD20+ follicular lymphoma received 4 weekly infusions of rituximab and those with a complete response (CR), partial response (PR), or stable disease received mitumprotimut-T and GM-CSF injections subcutaneously. Courses were given monthly for 6 doses, every 2 months for 6 doses, and then every 3 months until disease progression. Computed tomography scans were obtained every 3 to 6 months and reviewed centrally. The primary endpoint was event-free survival (EFS). Among 103 patients treated with rituximab, 92 (54 relapsed/refractory and 38 previously untreated) received mitumprotimut-T/GM-CSF; median age was 53 years, 91% had stage III to IV disease, and 59% had failed earlier therapy. The premitumprotimut-T objective response rate was 47% (2 CRs, 41 PRs). During the mitumprotimut-T treatment phase, 16 patients converted to CR resulting in an overall objective response rate of 60% (18 CRs, 37 PRs). Median EFS was 15.2, 20.8, and 13.5 months for all, treatment-naive, and relapsed/refractory disease patients, respectively. Anti-Id cellular immune responses were detected in 13 of 18 (72%) patients and humoral immune responses in 17 of 83 (20%) patients. Adverse events were usually mild-to-moderate. The most common adverse event was injection site reactions. Mitumprotimut-T/GM-CSF-induced anti-Id cellular immune responses in most patients. The occurrence of late CRs and favorable EFS suggested a clinical benefit of active immunotherapy and led to a placebo-controlled phase 3 trial.

Background: Standard therapeutic regimens for older HL patients (pts) may confer significantly increased toxicity and inferior survival compared with younger pts. Reported complete remission (CR) rates for older pts are 45-76% with 2-year (yr) progression-free survival (PFS) rates of 50-71% (eg, Evens et al. Blood 2012). With a goal of improving outcomes for older cHL pts, this multicenter phase 2 study tested Bv given sequentially before and after standard AVD chemotherapy. Methods: Older pts (aged ≥60 yrs) with stage IIB-IV, untreated cHL were eligible. Pts received 2 'lead-in' doses of single-agent Bv 1.8 mg/kg (q 3 weeks) followed by 6 cycles of standard AVD. Supportive antibiotics were encouraged & granulocyte growth factor was allowed. Responding pts proceeded to consolidation (Cx) therapy with 4 Bv cycles. Study design was a Simon 2-stage; the primary endpoint was CR rate after AVD (ie, prior to Bv Cx) using revised Cheson with FDG-PET; pts must have received 2 cycles of AVD to be evaluable for response. The study was considered promising if >70% of evaluable pts demonstrated CR. Univariate & multivariate analyses (MVA) were performed using Cox proportional hazard regression for associations between lab and clinical factors (including co-morbidities assessed by the Cumulative Illness Rating Scale (CIRS)) with survival. Results: 48 pts enrolled to the study (8/2012-8/2016) with 41 being evaluable for response. Characteristics for all pts included: median age 69 yrs (60-88); 30M:18F; median ECOG PS of 1 (21% PS=2); 82% stage III/IV disease (bone marrow involved 23%); and IPS 3-7 in 60%. No pts had loss of activities of daily living (ADL) at baseline, while 12% had loss of instrumental ADLs. Median CIRS co-morbidity score at baseline was 6 (0-20). 6 pts received 1 pt were neutropenia (60%); infection (15%), febrile neutropenia (8%); transaminitis (6%); renal insufficiency (6%); urinary infection (6%); pneumonia (6%); hyponatremia (6%); fatigue (6%); febrile neutropenia (6%); diarrhea (4%); pancreatitis (4%), & peripheral neuropathy (PN) (4%). 33% of all pts experienced grade 2 PN (6% motor/27% sensory); the majority were reversible. Treatment related mortality on study was 2% (n=1 pancreatitis). Reasons for study discontinuation were: completed treatment (52%); toxicity/AEs (33%); withdrew consent/refused additional treatment (9%); & progressive disease or death (6%). Finally, for pt prognostication, increasing age (continuous) (P=0.005), female (P=0.05) & increased CIRS (continuous) (P=0.006) were associated with inferior PFS on univariate analysis; on MVA, only increasing age remained significant (HR 1.19 per yr >60, 95%CI 1.02-1.37, P=0.02). Conclusions: Bv-AVD incorporating Bv sequentially before and after chemotherapy represents among the best-reported outcomes to date for untreated older cHL pts. Efforts to maintain these robust remission and survival rates, but with less toxicity, should be a focus of ongoing investigation. This should include response-adapted design and integration of other novel agents (eg, checkpoint inhibitors), especially for pts with advanced ages and/or multiple co-morbidities. Disclosures Evens: Novartis: Consultancy; Affimed: Consultancy; Merck: Consultancy; Kite Pharma: Consultancy; Amgen: Consultancy; Celgene: Consultancy; Millennium: Consultancy; AbbVie: Consultancy; Pharmacyclics: Consultancy; Seattle Genetics: Consultancy; • Spectrum Pharmaceuticals: Consultancy. Advani: Spectrum: Consultancy; Gilead: Consultancy; Agensys: Research Funding; Bayer Healthcare Pharmaceuticals: Research Funding; Merck: Research Funding; Celgene: Research Funding; Seattle Genetics: Research Funding; Kura: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Nanostring: Consultancy; FortySeven: Research Funding; Janssen: Research Funding; Cell Medica: Research Funding; Millennium: Research Funding; Pharmacyclics: Consultancy; Sutro: Consultancy; Juno Therapeutics: Consultancy; Pharmacyclics: Research Funding; Infinity: Research Funding; Genentech: Research Funding. Fanale: ONYX: Research Funding; CELGENE: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; TAKEDA: Honoraria, Research Funding; AMGEN: Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; SEATTLE GENETICS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; GENENTECH: Research Funding; MERCK: Membership on an entity's Board of Directors or advisory committees, Research Funding; MOLECULAR TEMPLATES: Research Funding; ADC THERAPEUTICS: Research Funding. Winter: Merck: Research Funding; Glaxo-Smith-Kline: Research Funding. Gordon: Janssen: Other: Data Monitoring Committee. Hamlin: Celgene: Consultancy, Honoraria; Portola: Consultancy, Honoraria, Other: research support; Incyte: Other: research support; Gilead: Consultancy, Honoraria; Novartis: Other: research support; Seattle Geneitcs: Other: research support.

Introduction: Follicular lymphoma (FL) is characterized by an indolent clinical course, but patients with this disease bear a risk of transformation to diffuse large B-cell lymphoma (DLBCL) or high-grade B-cell lymphoma (HGBL). DLBCL transformed from FL (tDLBCL) traditionally has been associated with an aggressive course and a post-transformation survival of 0.6-1.7 years. However, a more recent study showed longer survivals in these patients, challenging the notion that transformation universally portends a poor prognosis in the immunotherapy era. Presence of concurrent FL at the time of diagnosis of DLBCL (cDLBCL/FL) also raises the possibility of transformation, but its clinical significance has not been elucidated in the literature. In this study, we analyzed and compared outcomes of tDLBCL, cDLBCL/FL, and de novo DLBCL. We also characterized the prevalence of MYC/BCL2/BCL6 gene rearrangements in tDLBCL and cDLBCL/FL cohorts and evaluated the impact of dual rearrangements (double hit, DH) on clinical outcomes. Methods: Patients diagnosed with DLBCL or B cell lymphoma unclassifiable with features intermediate between DLBCL and Burkitt lymphoma, also known as HGBL (BCLU/HGBL), treated at Northwestern University or University of Pennsylvania from 1/2010 to 7/2016 were included. Patients with Burkitt lymphoma, primary CNS and HIV-associated lymphoma were excluded. Transformation was defined as presence of DLBCL/ BCLU/HGBL in cases with an antecedent diagnosis of FL by at least 6 months. We divided our cohort into three groups: 1. De novo DLBCL or BCLU/HGBL with no prior history of FL (dDLBCL) 2. Transformed FL (tDLBCL) and 3. DLBCL or BCLU/HGBL with concurrent FL (cDLBCL/FL). Progression free survival (PFS) was defined as time from diagnosis to radiographic progression, regimen change, death or last follow-up. Overall survival (OS) was defined as time from diagnosis to death or last follow-up. Kaplan-Meier (KM) survival analyses, using a log-rank p-values were performed for PFS and OS to compare the three diagnosis groups (dDLBCL, tDLBCL, and cDLBCL; alpha=0.05) and pairwise comparisons of combinations of diagnosis (dDLBCL and tDLBCL+cDLBCL) and double hit status (accounting for multiple comparisons with a Bonferroni corrected alpha=0.013). Fluorescence in situ hybridization for MYC, BCL2 and BCL6 rearrangements was performed using break-apart probes per the policy of each institution. Results: A total of 293 pts, including 233 dDLBCL, 37 tDLBCL, and 23 cDLBCL/FL were included. 50% of the tDLBCL received at cytotoxic chemotherapy before transformation for precedent FL. Age and sex distribution, as well as clinical characteristics including stage, ECOG performance status, IPI score, and primary refractoriness were similar amongst the three groups. LDH was more likely to be elevated in dDLBCL (75%), as compared to tDLBCL(63%) and cDLBCL/FL (47%)( p=0.02%). Additionally, non-bone marrow extra-nodal disease was seen more often in dDLBCL (72%), as compared with tDLBCL (53%) and cDLBCL/FL (43%)( p Conclusions: DLBCLs transformed from FL or with concurrent diagnosis of FL (composite lymphoma) demonstrated similar clinical outcomes in our study. However, dual rearrangements are more prevalent in these patients and drive inferior survival similar to DH status in de novo DLBCL. Figure 1 Figure 1. Disclosures Landsburg: Curis: Consultancy, Research Funding; Takeda: Research Funding. Winter: Merck: Research Funding; Glaxo-Smith-Kline: Research Funding. Pro: Seattle Genetics: Consultancy; Takeda: Consultancy, Research Funding; Celgene: Consultancy, Research Funding. Gordon: Janssen: Other: Data Monitoring Committee. Karmali: Celgene: Speakers Bureau. Kaplan: Millennium: Research Funding; Takeda: Research Funding; Seattle Genetics: Research Funding; Janssen: Research Funding.

Incorporation of the anti-CD20 monoclonal antibody rituximab into front-line regimens for diffuse large B-cell lymphoma (DLBCL) has resulted in improved survival. Despite this progress, many patients develop refractory or recurrent DLBCL and then receive autologous hematopoietic stem cell transplantation (AuHCT). It is unclear to what extent pre-transplant exposure to rituximab affects outcomes following AuHCT. Outcomes of 994 patients receiving AuHCT for DLBCL between 1996 and 2003 were analyzed according to whether rituximab was (n=176, “+R” group) or was not (n=818, “ −R” group) administered with front-line or salvage therapy prior to AuHCT. The +R group had superior progression-free survival (50% versus 38%, p=0.008) and overall survival (57% versus 45%, p=0.006) at 3 years. Platelet and neutrophil engraftment were not affected by exposure to rituximab. Non-relapse mortality (NRM) did not differ significantly between the +R and −R groups. In multivariate analysis, the +R group had improved progression-free survival (relative risk of relapse/progression or death 0.64, p

Purpose To evaluate patient-specific immunotherapy with mitumprotimut-T (idiotype keyhole limpet hemocyanin [Id-KLH]) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in CD20+ follicular lymphoma. Patients and Methods Patients with treatment-naive or relapsed/refractory disease achieving a complete response (CR), partial response (PR), or stable disease (SD) with four weekly rituximab infusions were randomly assigned to mitumprotimut-T/GM-CSF or placebo/GM-CSF, with doses given monthly for six doses, every 2 months for six doses, and then every 3 months until disease progression (PD). Randomization was stratified by prior therapy (treatment-naive or relapsed/refractory) and response to rituximab (CR/PR or SD). The primary end point was time to progression (TTP) from randomization. Results A total of 349 patients were randomly assigned; median age was 54 years, 79% were treatment naive, and 86% had stage III/IV disease. Median TTP was 9.0 months for mitumprotimut-T/GM-CSF and 12.6 months for placebo/GM-CSF (hazard ratio [HR] = 1.384; P = .019). TTP was comparable between the two arms in treatment-naive patients (HR = 1.196; P = .258) and shorter with mitumprotimut-T/GM-CSF in relapsed/refractory disease (HR = 2.265; P = .004). After adjusting for Follicular Lymphoma International Prognostic Index (FLIPI) scores, the difference in TTP between the two arms was no longer significant. Overall objective response rate, rate of response improvement, and duration of response were comparable between the two arms. Toxicity was similar in the two arms; 76% of adverse events were mild or moderate, and 94% of patients had injection site reactions. Conclusion TTP was shorter with mitumprotimut-T/GM-CSF compared with placebo/GM-CSF. This difference was possibly due to the imbalance in FLIPI scores.

PURPOSE OF REVIEW To critically assess recent advances in the treatment of indolent non-Hodgkin lymphoma with a focus on immunologically based therapies. RECENT FINDINGS Modern treatment strategies, including monoclonal antibodies targeting lymphoma-associated antigens, radioimmunotherapy, therapeutic vaccination and allogeneic hematopoietic stem cell transplantation, have the potential to profoundly impact clinical outcomes in indolent lymphoma therapy. The results of randomized phase III trials now indicate that the addition of rituximab to combination chemotherapy prolongs progression-free and overall survival compared to chemotherapy alone. It is anticipated that similar improvements in outcomes will be associated with other immunologic strategies. SUMMARY Many questions remain unanswered regarding the optimal treatment approach for patients with indolent lymphoma. Randomized phase III trials addressing the key issues in patient management are ongoing. Continued follow-up of treated patients will be required to assess the character and frequency of long-term toxicities, and to provide insights into the best sequencing of treatments. It is likely that combinations of new treatment strategies will have the greatest impact on long-term clinical outcome. New insights into the underlying biology of the indolent lymphomas are anticipated to help guide therapy for individual patients and to provide new therapeutic targets.

// Zijun Y. Xu-Monette 1,* , Meifeng Tu 2,* , Kausar J. Jabbar 1 , Xin Cao 1 , Alexandar Tzankov 3 , Carlo Visco 4 , Qingqing Cai 1 , Santiago Montes-Moreno 5 , Yuji An 1 , Karen Dybkaer 6 , April Chiu 7 , Attilio Orazi 8 , Youli Zu 9 , Govind Bhagat 10 , Kristy L. Richards 11 , Eric D. Hsi 12 , William W.L. Choi 13 , J. Han van Krieken 14 , Jooryung Huh 15 , Maurilio Ponzoni 16 , Andres J.M. Ferreri 16 , Xiaoying Zhao 17 , Michael B. Moller 18 , John P. Farnen 19 , Jane N. Winter 20 , Miguel A. Piris 5 , Roberto N. Miranda 1 , L. Jeffrey Medeiros 1 and Ken H. Young 1,21 1 Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA 2 Peking University Cancer Hospital and Institute, Beijing, China 3 University Hospital, Basel, Switzerland 4 San Bortolo Hospital, Vicenza, Italy 5 Hospital Universitario Marques de Valdecilla, Santander, Spain 6 Aalborg University Hospital, Aalborg, Denmark 7 Memorial Sloan-Kettering Cancer Center, New York, NY, USA 8 Weill Medical College of Cornell University, New York, NY, USA 9 The Methodist Hospital, Houston, TX, USA 10 Columbia University Medical Center and New York Presbyterian Hospital, New York, NY, USA 11 University of North Carolina School of Medicine, Chapel Hill, NC, USA 12 Cleveland Clinic, Cleveland, OH, USA 13 University of Hong Kong Li Ka Shing Faculty of Medicine, Hong Kong, China 14 Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands 15 Asan Medical Center, Ulsan University College of Medicine, Seoul, Korea 16 San Raffaele H. Scientific Institute, Milan, Italy 17 Zhejiang University School of Medicine, Second University Hospital, Hangzhou, China 18 Odense University Hospital, Odense, Denmark 19 Gundersen Lutheran Health System, La Crosse, WI, USA 20 Feinberg School of Medicine, Northwestern University, Chicago, IL, USA 21 The University of Texas School of Medicine, Graduate School of Biomedical Sciences, Houston, Texas, USA * These authors made equal contributions to this work Correspondence to: Ken H. Young, email: // Keywords : ABC, BCL2, CD5, diffuse large B-cell lymphoma, NF-κB Received : December 29, 2014 Accepted : January 02, 2015 Published : March 08, 2015 Abstract CD5 is a pan-T-cell surface marker and is rarely expressed in diffuse large B-cell lymphoma (DLBCL). Large-scale studies of de novo CD5 + DLBCL are lacking in Western countries. In this study by the DLBCL Rituximab-CHOP Consortium, CD5 was expressed in 5.5% of 879 DLBCL patients from Western countries. CD5 + DLBCL was associated with higher frequencies of >1 ECOG performance status, bone marrow involvement, central nervous system relapse, activated B-cell–like subtype, Bcl-2 overexpression, and STAT3 and NF-κB activation, whereas rarely expressed single-stranded DNA-binding protein 2 (SSBP2), CD30 or had MYC mutations. With standard R-CHOP chemotherapy, CD5 + DLBCL patients had significantly worse overall survival (median, 25.3 months vs . not reached, P < .0001) and progression-free survival (median, 21.3 vs. 85.8 months, P < .0001) than CD5 – DLBCL patients, which was independent of Bcl-2, STAT3, NF-κB and the International Prognostic Index. Interestingly, SSBP2 expression abolished the prognostic significance of CD5 expression, suggesting a tumor-suppressor role of SSBP2 for CD5 signaling. Gene-expression profiling demonstrated that B-cell receptor signaling dysfunction and microenvironment alterations are the important mechanisms underlying the clinical impact of CD5 expression. This study shows the distinctive clinical and biological features of CD5 + DLBCL patients in Western countries and underscores important pathways with therapeutic implications.

S224 516 Nuclear coexpression of NF-kB subunit c-Rel and p53 mutants confers significantly poor survival in diffuse large B-cell lymphoma patients treated with rituximab-CHOP immunochemotherapy: A Report from the International DLBCL Rituximab-CHOP Consortium Ling Li, Zijun Y. Xu-Monette, Chi Y. Ok, Ganiraju C. Manyam, Carlo Visco, Alexander Tzankov, Santiago Montes-Moreno, Karen Dybkaer, April Chiu, Attilio Orazi, Youli Zu, Govind Bhagat, Kristy L. Richards, Eric D. Hsi, William W.L. Choi, J. Han van Krieken, Jooryung Huh, Maurilio Ponzoni, Andres J.M. Ferreri, John P. Farnen, Michael B. Moller, Miguel A. Piris, Jane N. Winter, L. Jeffrey Medeiros, Ken H. Young Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA; Department of Biostatistics and Bioinformatics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA; San Bartolo Hospital, Vicenza, Italy; University Hospital, Basel, Switzerland; Hospital Universitario Marques de Valdecilla, Santander, Spain; Aalborg University Hospital, Aalborg, Denmark; Memorial Sloan-Kettering Cancer Center, New York, NY, USA; Weill Medical College of Cornell University, New York, NY, USA; The Methodist Hospital, Houston, TX, USA; Columbia University Medical Center and New York Presbyterian Hospital, New York, NY, USA; University of North Carolina School of Medicine, Chapel Hill, NC, USA; Cleveland Clinic, Cleveland, OH, USA; University of Hong Kong Li Ka Shing Faculty of Medicine, Hong Kong, China; Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; Asan Medical Center, Ulsan University College of Medicine, Seoul, Korea; San Raffaele H. Scientific Institute, Milan, Italy; Gundersen Lutheran Health System, La Crosse, WI, USA; Odense University Hospital, Odense, Denmark; Feinberg School of Medicine, Northwestern University, Chicago, IL, USA

High-dose therapy followed by autologous hematopoietic stem-cell transplantation is the preferred therapy for relapsed chemotherapy-sensitive aggressive non-Hodgkin lymphoma, and may play a role in the treatment of high-risk first-remission aggressive lymphomas, mantle-cell lymphomas and relapsed follicular lymphomas. The primary cause of failure of this approach is disease recurrence despite initial responses. Traditional high-dose regimens have relied upon myeloablative combinations of chemotherapy with or without total body irradiation. In the Western world, over 90% of lymphomas are of B-cell origin, and the vast majority of those that come to transplant remain CD20-positive. The development of radioimmunotherapeutic approaches targeting this antigen allows for either dose escalation with stem-cell support, or the addition of targeted therapy to conditioning regimens either as a replacement for total body irradiation or in addition to myeloablative chemotherapy regimens. Results to date with yttrium-90 ibritumomab tiuxetan (Zevalin ® ) and I-131 tositumomab (Bexxar ® ) suggest that the addition of radioimmunoconjugate therapy to conventional conditioning regimens results in a toxicity profile similar to that seen with chemotherapy conditioning alone. Demonstration of improved disease control will ultimately require phase-III studies, though preliminary results are promising.

Follicular lymphoma (FL) is characterized by its responsiveness to initial therapy, a pattern of repeated relapses, and a tendency for histologic progression to a process resembling diffuse, large B-cell lymphoma. Treatment decisions are complicated by the many effective options now available including combinations of conventional chemotherapy and monoclonal antibody, radioimmunotherapy, new targeted agents, and autologous and allogeneic stem cell transplantation. For selected patients, "watch and wait" or involved field irradiation may still be the most appropriate strategy. When therapy is required, a combination of rituximab and conventional chemotherapy results in improved outcomes compared to chemotherapy alone. Radioimmunotherapy alone or in combination with chemotherapy is an attractive strategy for patients with relapsed disease and may prove to be appropriate first line therapy. The role of stem cell transplant in FL requires further investigation. Novel agents with varied mechanisms of action continue to be developed. Enrollment of patients into clinical trials designed to address the many unanswered questions in FL is essential to improving clinical outcomes.

Over the past two decades, the incidence of follicular lymphoma has increased. Contemporary treatments include combinations of chemotherapy and monoclonal antibodies, radioimmunotherapy, new targeted agents and stem-cell transplantation. Prognostic tools are becoming more important in helping clinicians and patients decide on the most appropriate therapeutic regimens. Gene expression profiling and biomarkers are promising additions to this armamentarium. When patients do require therapy, the addition of rituximab to chemotherapy seems to improve remission duration and may improve overall survival. Radioimmunotherapy capitalises on the capacity to target radiation directly to malignant cells, and is currently approved for the treatment of relapsed/refractory follicular lymphoma. Further investigation is needed to clarify the role of stem-cell transplantation in follicular lymphoma. Only well-designed clinical trials can provide answers to the many questions that remain regarding the optimal treatment and sequence of treatments for patients with follicular lymphoma.

Targeted radioimmunotherapy, including yttrium 90-labeled ibritumomab tiuxetan (Zevalin) and iodine I 131 tositumomab (Bexxar), has the potential to increase the cure rate for patients with CD20+ B-cell malignancies who are undergoing autologous hematopoietic stem cell transplantation. The results of phase I and II trials suggest that radioimmunoconjugates can be safely combined with high-dose chemotherapy, although the optimal approach remains to be established. This review focuses on the use of 90Y ibritumomab tiuxetan combined with high-dose chemotherapy in the setting of autologous hematopoietic stem cell transplantation.