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Supplementary Figure from Phase Ib/II Study of Enzalutamide with Samotolisib (LY3023414) or Placebo in Patients with Metastatic Castration-Resistant Prostate Cancer

Purpose:To report efficacy and safety of samotolisib (LY3023414; PI3K/mTOR dual kinase and DNA-dependent protein kinase inhibitor) plus enzalutamide in patients with metastatic castration-resistant prostate cancer (mCRPC) following cancer progression on abiraterone.Patients and Methods:In this double-blind, placebo-controlled phase Ib/II study (NCT02407054), following a lead-in segment for evaluating safety and pharmacokinetics of samotolisib and enzalutamide combination, patients with advanced castration-resistant prostate cancer with progression on prior abiraterone were randomized to receive enzalutamide (160 mg daily)/samotolisib (200 mg twice daily) or placebo. Primary endpoint was progression-free survival (PFS) assessed by Prostate Cancer Clinical Trials Working Group criteria (PCWG2). Secondary and exploratory endpoints included radiographic PFS (rPFS) and biomarkers, respectively. Log-rank tests assessed treatment group differences.Results:Overall, 13 and 129 patients were enrolled in phase Ib and II, respectively. Dose-limiting toxicity was not reported in patients during phase Ib and mean samotolisib exposures remained in the targeted range despite a 35% decrease when administered with enzalutamide. In phase II, median PCWG2-PFS and rPFS was significantly longer in the samotolisib/enzalutamide versus placebo/enzalutamide arm (3.8 vs. 2.8 months; P = 0.003 and 10.2 vs. 5.5 months; P = 0.03), respectively. Patients without androgen receptor splice variant 7 showed a significant and clinically meaningful rPFS benefit in the samotolisib/enzalutamide versus placebo/enzalutamide arm (13.2 months vs. 5.3 months; P = 0.03).Conclusions:Samotolisib/enzalutamide has tolerable side effects and significantly improved PFS in patients with mCRPC with cancer progression on abiraterone, and this may be enriched in patients with PTEN intact and no androgen receptor splice variant 7.

Background: Umbralisib is an oral, once-daily, novel, dual inhibitor of phosphatidylinositol-3-kinase-delta (PI3Kδ) and casein kinase-1ε (CK1ε) that exhibits improved selectivity for the delta isoform of PI3K. Ublituximab is a novel anti-CD20 monoclonal antibody glycoengineered for enhanced antibody-dependent cellular cytotoxicity that targets a unique epitope on CD20. U2 has been well-tolerated and demonstrated promising activity in heavily pre-treated CLL patients. Herein, results are presented for the randomized, multicenter, Phase 3 UNITY-CLL trial (NCT02612311), which evaluated U2 vs O+Chl in patients with TN and R/R CLL. Methods: Patients ≥18 years of age with treatment-naïve (TN) or relapsed/refractory (R/R) CLL requiring treatment per iwCLL criteria with adequate organ function and ECOG PS ≤2 were eligible. Stratification factors included treatment status (TN vs R/R) and del(17p) status. Patients were initially randomized 1:1:1:1 to receive U2, O+Chl, umbralisib monotherapy, or ublituximab monotherapy. Following establishment of contribution comparing U2 to the single agents, patients were randomized 1:1 to U2 or O+Chl. Umbralisib was given orally at 800 mg once-daily until progression or removal from treatment for other reasons. Ublituximab was administered intravenously at 900 mg on Days 1/2 [split 150/750 mg], 8, and 15 of Cycle 1, Day 1 of Cycles 2 - 6, and on Day 1 every 3 cycles after Cycle 6. O was given intravenously at 1000 mg on Days 1/2 [split 100/900], 8, and 15 of Cycle 1, and Day 1 of Cycles 2 - 6. Chl was given orally at 0.5 mg/kg on Day 1 and 15 of Cycles 1 - 6. Each cycle was 28 days. The primary endpoint was independent review committee (IRC)-assessed progression-free survival (PFS) of U2 vs O+Chl. Key secondary endpoints included IRC-assessed overall response rate (ORR), complete response (CR), undetectable minimal residual disease (uMRD), duration of response (DOR), and safety (assessed from the first dose until 30 days after the last dose of study medication in each arm) as well as contribution of umbralisib and ublituximab to the U2 combination. Results: From Feb 2016 - Oct 2017, 421 pts were randomized to the U2 (n=210) or O+Chl (n=211) arms. The median age was 67 y (range, 36-91); 57% of patients (n=240) were treatment-naïve; 43% (n=181) had R/R CLL (median number of prior treatments = 1); 10% had del(17p), 20% del(11q), and 56% were IgHV unmutated. 66% were male. Demographics were well-balanced between treatment arms. At a median follow-up of 36.2 mos, U2 significantly prolonged PFS vs O+Chl (median 31.9 mos vs 17.9 mos; HR 0.546, 95% CI 0.413-0.720, P The median treatment duration was 23 mos for U2 (range, 0.1 - 49 mos) and 5 mos (range, 0.1 - 7 mos) for O+Chl. G3/4 AEs of interest regardless of causality (U2 vs O+Chl) included neutropenia (30.6% vs 34.7%), thrombocytopenia (3.4% vs 13.1%), diarrhea (12.1% vs 2.5%), infusion related reaction (1.9% vs 3.5%), elevated AST/ALTs (8.3% vs 2%), colitis (3.4% vs 0%) and pneumonitis (2.9% vs 0%). AEs led to treatment discontinuation in 34 patients (16.5%) on U2 and 16 patients (7.6%) on O+Chl. Conclusions: UNITY-CLL is the first randomized Phase 3 study in CLL of a PI3Ki vs. chemoimmunotherapy, and the first randomized study of a PI3Ki in treatment-naive CLL. U2 exhibited a well-tolerated safety profile, and significantly improved PFS vs. standard of care chemoimmunotherapy in patients with treatment-naive and relapsed/refractory CLL. Figure Disclosures Gribben: Janssen: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; Celgene: Research Funding; Abbvie: Honoraria. Jurczak:Celgene: Research Funding; Afimed: Research Funding; Sandoz-Novartis: Consultancy; European Medicines Agency,: Consultancy; AstraZeneca: Consultancy; Takeda: Research Funding; Janssen China R&D: Consultancy, Research Funding; BeiGene: Consultancy, Research Funding; Bayer: Research Funding; Acerta: Consultancy, Research Funding; Pharmacyclics: Research Funding; Maria Sklodowska-Curie National Research Institute of Oncology, Krakow, Poland: Current Employment; MEI Pharma: Research Funding; Nordic Nanovector: Research Funding; Servier: Research Funding; Merck: Research Funding; Gilead Sciences: Research Funding; Epizyme: Consultancy; Roche: Research Funding; MorphoSys: Research Funding; TG Therapeutics, Inc.: Research Funding; Jagiellonian University, Krakow, Poland: Ended employment in the past 24 months. Jacobs:Sanofi Genzyme: Speakers Bureau; Genentech: Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Verastem: Consultancy; Seattle Genetics: Consultancy; Astra Zeneca: Consultancy, Speakers Bureau; AbbVie: Consultancy, Speakers Bureau; Pharmacyclics: Research Funding, Speakers Bureau; TG Therapeutics, Inc.: Research Funding. Giannopoulos:BMS-Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding; Janssen: Honoraria. Wrobel:Janssen-Cilag: Honoraria, Research Funding, Speakers Bureau. Zafar:Bristol Meyers Squibb: Honoraria, Other: TRAVEL, ACCOMODATIONS, EXPENSES (paid by any for-profit health care company); Florida Cancer Specialists and Research Institute: Current Employment; Sarah Canon Research Institute: Research Funding; Karyopharm: Honoraria; AstraZeneca: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Danilov:Nurix: Consultancy; Celgene: Consultancy; Astra Zeneca: Consultancy, Research Funding; Aptose Biosciences: Research Funding; Gilead Sciences: Research Funding; Verastem Oncology: Consultancy, Research Funding; Pharmacyclics: Consultancy; Abbvie: Consultancy; BeiGene: Consultancy; Takeda Oncology: Research Funding; Karyopharm: Consultancy; TG Therapeutics: Consultancy; Genentech: Consultancy, Research Funding; Rigel Pharmaceuticals: Consultancy; Bristol-Myers Squibb: Research Funding; Bayer Oncology: Consultancy, Research Funding. Burke:Gilead: Consultancy; Epizyme: Consultancy; Adaptive: Consultancy; Kura: Consultancy; Astra Zeneca: Consultancy; Bayer: Consultancy; Bristol Myers Squibb: Consultancy; AbbVie: Consultancy; Adaptive Biotechnologies: Consultancy; Morphosys: Consultancy; Verastem: Consultancy; Roche: Consultancy; Seattle Genetics: Speakers Bureau; Celgene: Consultancy. Goldschmidt:Bristol-Myers Squibb: Speakers Bureau; Amgen: Consultancy; Blue Ridge Cancer Care: Current Employment. Huntington:Genentech: Consultancy; Astrazeneca: Honoraria; TG Therapeutics: Research Funding; Pharmacyclics: Honoraria; Novartis: Consultancy; Celgene: Consultancy, Research Funding; Bayer: Consultancy, Honoraria; AbbVie: Consultancy; DTRM: Research Funding. Pinilla Ibarz:AstraZeneca: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Novartis: Consultancy; Sunesis Pharmaceuticals: Consultancy; TG Therapeutics: Consultancy; Sanofi: Consultancy; Pharmacyclics: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Abbvie: Consultancy, Speakers Bureau. Sharman:Bristol Meyers Squibb: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; Roche: Consultancy, Research Funding; Acerta: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; BeiGene: Research Funding. Siddiqi:AstraZeneca: Consultancy, Research Funding, Speakers Bureau; Pharmacyclics: Consultancy, Research Funding, Speakers Bureau; Celgene: Consultancy, Research Funding; Juno: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; BeiGene: Consultancy, Research Funding; Oncternal: Research Funding; TG Therapeutics: Research Funding; Janssen: Speakers Bureau; Seattle Genetics: Speakers Bureau. Brander:MEI Pharma: Other, Research Funding; Pfizer: Consultancy, Other; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Other, Research Funding; Novartis: Consultancy, Other; Teva: Consultancy, Honoraria; Tolero: Research Funding; ArQule: Consultancy, Other, Research Funding; Ascentage: Other, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Tolero: Research Funding; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; NCCN: Other; Verastem: Consultancy, Honoraria, Other, Research Funding; Teva: Consultancy, Honoraria; Novartis: Consultancy, Other; AstraZeneca: Consultancy, Honoraria, Other, Research Funding; BeiGene: Other, Research Funding; DTRM: Other, Research Funding; NCCN: Other; Genentech: Consultancy, Honoraria, Other, Research Funding; Juno/Celgene/BMS: Other, Research Funding. Kolibaba:TG Therapeutics, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Research Funding; Sumitomo Dainippon Pharma Oncology: Consultancy, Other; Verastem: Honoraria; Genentech: Research Funding; Gilead: Research Funding; Janssen: Research Funding; McKesson Life Sciences: Consultancy; Novartis: Research Funding; Pharmacyclics: Research Funding; Acerta: Research Funding; AbbVie: Research Funding; Atara Biotech: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Cell Therapeutics: Research Funding; Compass Oncology: Ended employment in the past 24 months. Ghosh:Karyopharm: Consultancy; Genmab: Consultancy, Speakers Bureau; AbbVie: Speakers Bureau; AstraZeneca: Speakers Bureau; Celgene/Bristol-Myers Squibb: Speakers Bureau; Forty Seven Inc: Consultancy, Other: Research Bureau, Research Funding; Janssen: Consultancy, Research Funding, Speakers Bureau; Juno/Celgene/Bristol-Myers Squibb: Consultancy, Research Funding; Kite/Gilead: Consultancy, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding, Speakers Bureau; SGN: Consultancy, Research Funding, Speakers Bureau; TG Therapeutics: Consultancy, Research Funding; Roche/Genentech: Research Funding. Sportelli:TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Miskin:TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. O'Connor:Astex Pharmaceuticals: Honoraria, Research Funding; Celgene: Honoraria, Other: Data Safety Monitoring Committee, Research Funding; TG Therapeutics: Current Employment, Current equity holder in publicly-traded company; Kymera Therapeutics: Current equity holder in private company, Honoraria, Membership on an entity's Board of Directors or advisory committees; Nomocan: Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Mundipharma: Other: Consulting; Servier: Consultancy. Weiss:TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Flinn:Iksuda Therapeutics: Consultancy; Curis: Research Funding; Infinity Pharmaceuticals: Research Funding; F. Hoffmann-La Roche: Research Funding; Vincera Pharma: Consultancy; Karyopharm Therapeutics: Research Funding; Gilead Sciences: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Verastem: Consultancy, Research Funding; Triphase Research & Development Corp.: Research Funding; Trillium Therapeutics: Research Funding; TG Therapeutics: Consultancy, Research Funding; Teva: Research Funding; Seattle Genetics: Consultancy, Research Funding; ArQule: Research Funding; Unum Therapeutics: Consultancy, Research Funding; Incyte: Research Funding; Forma Therapeutics: Research Funding; Loxo: Research Funding; BeiGene: Consultancy, Research Funding; Kite Pharma: Consultancy, Research Funding; MorphoSys: Consultancy, Research Funding; Forty Seven: Research Funding; Genentech, Inc.: Research Funding; Great Point Partners: Consultancy; IGM Biosciences: Research Funding; Juno Therapeutics: Consultancy, Research Funding; Acerta Pharma: Research Funding; AbbVie: Consultancy, Research Funding; Celgene: Research Funding; Johnson & Johnson: Other; Yingli Pharmaceuticals ≠: Consultancy, Research Funding; Rhizen Pharmaceuticals: Research Funding; Roche: Consultancy, Research Funding; Curio Science: Consultancy; Nurix Therapeutics: Consultancy; Takeda: Consultancy, Research Funding; Calithera Biosciences: Research Funding; Merck: Research Funding; Constellation Pharmaceuticals: Research Funding; Agios: Research Funding; Portola Pharmaceuticals: Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; Pfizer: Research Funding; Novartis: Research Funding.

Background Ramucirumab-an IgG1 vascular endothelial growth factor receptor 2 antagonistplus docetaxel was previously reported to improve progression-free survival in platinum-refractory, advanced urothelial carcinoma. Here, we report the secondary endpoint of overall survival results for the RANGE trial.Methods We did a randomised, double-blind, phase 3 trial in patients with advanced or metastatic urothelial carcinoma who progressed during or after platinum-based chemotherapy. Patients were enrolled from 124 investigative sites (hospitals, clinics, and academic centres) in 23 countries. Previous treatment with one immune checkpoint inhibitor was permitted. Patients were randomly assigned (1:1) using an interactive web response system to receive intravenous ramucirumab 10 mg/kg or placebo 10 mg/kg volume equivalent followed by intravenous docetaxel 75 mg/m 2 (60 mg/m 2 in Korea, Taiwan, and Japan) on day 1 of a 21-day cycle. Treatment continued until disease progression, unacceptable toxicity, or other discontinuation criteria were met. Randomisation was stratified by geographical region, Eastern Cooperative Oncology Group performance status at baseline, and visceral metastasis. Progression-free survival (the primary endpoint) and overall survival (a key secondary endpoint) were assessed in the intention-to-treat population. The study is registered with ClinicalTrials.gov, NCT02426125; patient enrolment is complete and the last patient on treatment is being followed up for safety issues.Findings Between July 20, 2015, and April 4, 2017, 530 patients were randomly allocated to ramucirumab plus docetaxel (n=263) or placebo plus docetaxel (n=267) and comprised the intention-to-treat population. At database lock (March 21, 2018) for the final overall survival analysis, median follow-up was 7.4 months (IQR 3.5-13.9). In our sensitivity analysis of investigator-assessed progression-free survival at the overall survival database lock, median progression-free survival remained significantly improved with ramucirumab compared with placebo (4.1 months [95% CI 3.3-4.8] vs 2.8 months [2.6-2.9]; HR 0.696 [95% CI 0.573-0.845]; p=0.0002). Median overall survival was 9.4 months (95% CI 7.9-11.4) in the ramucirumab group versus 7.9 months (7.0-9.3) in the placebo group (stratified HR 0.887 [95% CI 0.724-1.086]; p=0.25). Grade 3 or worse treatment-related treatment-emergent adverse events in 5% or more of patients and with an incidence more than 2% higher with ramucirumab than with placebo were febrile neutropenia (24 [9%] of 258 patients in the ramucirumab group vs 16 [6%] of 265 patients in the placebo group) and neutropenia (17 [7%] of 258 vs six [2%] of 265). Serious adverse events were similar between groups (112 [43%] of 258 patients in the ramucirumab group vs 107 [40%] of 265 patients in the placebo group). Adverse events related to study treatment and leading to death occurred in eight (3%) patients in the ramucirumab group versus five (2%) patients in the placebo group.Interpretation Additional follow-up supports that ramucirumab plus docetaxel significantly improves progression-free survival, without a significant improvement in overall survival, for patients with platinum-refractory advanced urothelial carcinoma. Clinically meaningful benefit might be restricted in an unselected population. Copyright (C) 2019 Elsevier Ltd. All rights reserved.

Summary Background Pre-clinical and clinical evidence suggests that simultaneous blockade of VEGF receptor-2 (VEGFR-2) and PD-1 or PD-L1 enhances antigen-specific T-cell migration, antitumour activity, and has favourable toxicity. In this study, we aimed to assess the safety and preliminary antitumour activity of ramucirumab (an IgG1 VEGFR-2 antagonist) combined with pembrolizumab (an IgG4 PD-1 antagonist) in patients with previously treated advanced gastric or gastro-oesophageal junction adenocarcinoma, non-small-cell lung cancer, or urothelial carcinoma. Methods We did a multicohort, non-randomised, open-label, phase 1a/b trial at 16 academic medical centres, hospitals, and clinics in the USA, France, Germany, Spain, and the UK. We enrolled adult patients aged 18 years or older with histologically confirmed gastric or gastro-oesophageal junction adenocarcinoma (cohorts A and B), non-small-cell lung cancer (cohort C), or urothelial carcinoma (cohort D), whose disease had progressed on one or two lines of previous therapy (for those with gastric or gastro-oesophageal junction adenocarcinoma) or one to three lines of previous therapy (for those with non-small-cell lung cancer and urothelial carcinoma) that included platinum (for all tumour types) or fluoropyrimidine or both (for gastric or gastro-oesophageal junction adenocarcinoma). Eligibility criteria included presence of measurable disease and an Eastern Cooperative Oncology Group performance status of 0–1. Patients with previously untreated gastric or gastro-oesophageal junction adenocarcinoma and non-small-cell lung cancer were also enrolled (in two additional separate cohorts); the results for these cohorts will be reported separately. The first 21-day treatment cycle was a dose-limiting toxicity observation period (phase 1a; safety run-in), followed by a phase 1b cohort expansion stage. Pembrolizumab 200 mg was administered intravenously on day 1, and intravenous ramucirumab was administered at 8 mg/kg on days 1 and 8 for cohort A or at 10 mg/kg on day 1 for cohorts B, C, and D, every 3 weeks, until disease progression or other discontinuation criteria were met. The primary endpoint was the safety and tolerability of ramucirumab in combination with pembrolizumab assessed by the incidence of adverse events in both phase 1a and 1b and as dose-limiting toxicities during phase 1a. The safety and activity analysis set included all patients who received at least one dose of study treatment. This trial is registered with ClinicalTrials.gov , number NCT02443324 , and is no longer enrolling patients. Findings Between July 30, 2015 and June 24, 2016, we enrolled and treated 92 patients (41 with gastric or gastro-oesophageal junction adenocarcinoma, 27 with non-small-cell lung cancer, and 24 with urothelial carcinoma). Median follow-up was 32·8 months (IQR 28·1–33·6). During the first cycle of treatment (phase 1a safety run-in; n=11), one patient with gastro-oesophageal junction adenocarcinoma who received the 8 mg/kg dose of ramucirumab had grade 3 abdominal pain, colitis, hepatitis, interstitial lung disease, and jaundice, and grade 4 cholestasis, and died on treatment on day 40; the death was deemed related to progressive disease. No additional dose-limiting toxicities occurred and the decision was made to maintain the full planned doses of ramucirumab and pembrolizumab in phase 1b (n=81). Treatment-related adverse events occurred in 75 (82%) of 92 patients, the most common of which was fatigue (in 33 patients [36%]), predominantly of grade 1 or 2 severity. 22 patients (24%) had one or more treatment-related adverse events of grade 3 or worse, most commonly hypertension (six patients; 7%) and colitis (five patients; 5%). Serious adverse events occurred in 53 (58%) of 92 patients, and were deemed related to treatment in 22 (24%) patients. The most common treatment-related serious adverse events were abdominal pain in patients with gastric or gastro-oesophageal junction adenocarcinoma (in three [7%] of 41 patients); asthenia and myocardial infarction in patients with non-small-cell lung cancer (two [7%] of 27 patients), and colitis in patients with urothelial carcinoma (two [8%] of 24 patients). Six (7%) of 92 patients discontinued treatment because of treatment-related adverse events, and one death (from pulmonary sepsis in a patient with gastric or gastro-oesophageal junction adenocarcinoma) was deemed related to treatment. The number of patients achieving an objective response was three (7%; 95% CI 1·5–19·9) of 41 in the gastric or gastro-oesophageal junction adenocarcinoma cohort, eight (30%; 13·8–50·2) of 27 in the non-small-cell lung cancer cohort, and three (13%, 2·7–32·4) in the urothelial carcinoma cohort. Interpretation Ramucirumab in combination with pembrolizumab showed a manageable safety profile with favourable antitumour activity in patients with previously treated advanced gastric or gastro-oesophageal junction adenocarcinoma, non-small-cell lung cancer, and urothelial carcinoma. Our results contribute to the growing evidence that supports dual inhibition of the VEGF–VEGFR2 and PD-1–PD-L1 pathways. This combination could be further explored with or without chemotherapy, especially for patients with tumours for which single-agent checkpoint inhibitors have shown no additional benefit over chemotherapy. Funding Eli Lilly and Company, and Merck and Co.

Purpose: To report efficacy and safety of samotolisib (LY3023414; PI3K/mTOR dual kinase and DNA-dependent protein kinase inhibitor) plus enzalutamide in patients with metastatic castration-resistant prostate cancer (mCRPC) following cancer progression on abiraterone. Patients and Methods: In this double-blind, placebo-controlled phase Ib/II study (NCT02407054), following a lead-in segment for evaluating safety and pharmacokinetics of samotolisib and enzalutamide combination, patients with advanced castration-resistant prostate cancer with progression on prior abiraterone were randomized to receive enzalutamide (160 mg daily)/samotolisib (200 mg twice daily) or placebo. Primary endpoint was progression-free survival (PFS) assessed by Prostate Cancer Clinical Trials Working Group criteria (PCWG2). Secondary and exploratory endpoints included radiographic PFS (rPFS) and biomarkers, respectively. Log-rank tests assessed treatment group differences. Results: Overall, 13 and 129 patients were enrolled in phase Ib and II, respectively. Dose-limiting toxicity was not reported in patients during phase Ib and mean samotolisib exposures remained in the targeted range despite a 35% decrease when administered with enzalutamide. In phase II, median PCWG2-PFS and rPFS was significantly longer in the samotolisib/enzalutamide versus placebo/enzalutamide arm (3.8 vs. 2.8 months; P = 0.003 and 10.2 vs. 5.5 months; P = 0.03), respectively. Patients without androgen receptor splice variant 7 showed a significant and clinically meaningful rPFS benefit in the samotolisib/enzalutamide versus placebo/enzalutamide arm (13.2 months vs. 5.3 months; P = 0.03). Conclusions: Samotolisib/enzalutamide has tolerable side effects and significantly improved PFS in patients with mCRPC with cancer progression on abiraterone, and this may be enriched in patients with PTEN intact and no androgen receptor splice variant 7.

Ramucirumab (anti-VEGFR2) plus pembrolizumab (anti-PD1) demonstrated promising antitumor activity and tolerability among patients with previously treated advanced cancers, supporting growing evidence that combination therapies modulating the tumor microenvironment may expand the spectrum of patients who respond to checkpoint inhibitors. Here we present the results of this combination in first-line patients with metastatic G/GEJ cancer. Twenty-eight patients (&ge, 18 years) with no prior systemic chemotherapy in the advanced/metastatic setting received ramucirumab (8 mg/kg days 1 and 8) plus pembrolizumab (200 mg day 1) every 3 weeks as part of JVDF phase 1a/b study. The primary endpoint was safety. Secondary endpoints included progression-free survival (PFS), objective response rate (ORR), and overall survival (OS). Tumors were PD-L1-positive (combined positive score &ge, 1) in 19 and -negative in 6 patients. Eighteen patients experienced grade 3 treatment-related adverse events, most commonly hypertension (14%) and elevated alanine/aspartate aminotransferase (11% each), with no grade 4 or 5 reported. The ORR was 25% (PD-L1-positive, 32%, PD-L1-negative, 17%) with duration of response not reached. PFS was 5.6 months (PD-L1-positive, 8.6 months, PD-L1-negative, 4.3 months), and OS 14.6 months (PD-L1-positive, 17.3 months, PD-L1-negative, 11.3 months). Acknowledging study design limitations, ramucirumab plus pembrolizumab had encouraging durable clinical activity with no unexpected toxicities in treatment-na&iuml, ve biomarker-unselected metastatic G/GEJ cancer, and improved outcomes in patients with PD-L1-positive tumors.

Background: Bruton tyrosine kinase inhibitors (BTKis) are important tools to treat B-cell malignancies. However, duration of treatment may be limited by adverse events (AEs). Zanubrutinib (zanu) is a BTKi approved for mantle cell lymphoma (MCL) and is in development for other hematologic malignancies. Data from phase 3 head-to-head trials of zanu vs ibrutinib (ibr) in pts with Waldenström macroglobulinemia (WM) or chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) demonstrated that pts treated with zanu showed lower rates of AEs leading to discontinuation (Blood 2020;136(18):2038-50; EHA 2021 LB1900). Preliminary results from BGB-3111-215 (NCT04116437) show that zanu was well-tolerated in pts who discontinued ibr and/or acalabrutinib (acala) treatment due to AEs (EHA 2021 EP642). Here, we report updated results from the BGB-3111-215 study with a median follow-up of 9 months. Methods: This study is an ongoing US, phase 2, multicenter, single-arm, open-label study. The safety and efficacy of zanu monotherapy (160 mg twice daily or 320 mg once daily) were evaluated in pts with B-cell malignancies who met criteria for continued treatment after having become intolerant to prior BTKi therapy. Pts were divided into cohort 1 (pts who were intolerant to ibr only) and cohort 2 (pts who were intolerant to acala alone/and ibr). Pts with documented progressive disease (PD) on prior BTKi therapy were excluded. Efficacy and safety, including recurrence of intolerant AEs to the prior BTKi, were evaluated. AEs were assessed for severity, seriousness, and relation to zanu; as well as dose reductions, holds, or discontinuations. Response was assessed by investigators based on response criteria for their respective indications (Blood 2008;131:2745; J Clin Oncol 2012;30:2820; J Clin Oncol 2014;32:3059; Br J Haemtol 2013;160:171). Disease parameters from study entry were the baseline for response assessment. Mutational analysis was performed on pts who discontinued treatment, and data will be shared once available. To support clinical findings, kinase selectivity was assessed using Kinome profiling at 100X IC50 (against BTK) for zanu, ibr, acala and its major metabolite, M27 (Reaction Biology Corp). Results: As of 7 June 2021 (data cutoff), 57 pts (n=44 CLL/SLL; n=9 WM; n=2 MCL; n=2 marginal zone lymphoma [MZL]) were enrolled in cohort 1, and 7 pts were enrolled in cohort 2 (n=4 CLL; n=1 WM; n=1 MCL; n=1 MZL). All received ≥1 dose of zanu and were analyzed for safety. The median age was 71 years (range, 49-91) in cohort 1 and 71 years (range, 65-76) in cohort 2; median duration of treatment was 8.7 months (range, 0.6-17.9) in cohort 1 and 8.2 months (range, 6.4-11.4) in cohort 2; median number of prior regimens was 1 (range, 1-12) in cohort 1 and 3 (range, 2-5) in cohort 2. Within cohort 2, 5 pts were intolerant to both ibr and acala. Median number of intolerant events per pt for both cohorts 1 and 2 was 2 (range, 1-5). Overall, 73% of pts did not experience recurrence of their ibr or acala intolerant events and 79% of recurrent events recurred at a lower severity (Figure 1). At cutoff, 54 pts remained on treatment. Reasons for treatment discontinuation were AEs (n=4), PD (n=4), physician's decision (n=1), and consent withdrawal (n=1). Grade ≥3 AEs were reported in 18 pts (28%), and serious AEs occurred in 7 pts (11%). AEs requiring dose interruptions occurred in 17 pts (27%), and AEs leading to dose reduction occurred in 3 pts (5%). One death, due to COVID-19, was reported. Pts demonstrated maintained (41%) and improved (53%) response with zanu treatment from their reported best overall response on prior BTKis for a total disease control rate of 94% (including a 42% partial response rate in pts with CLL/SLL, 30% in pts with WM, and a 20% very good partial response rate in pts with WM). Zanu also demonstrated good selectivity by kinase profiling. It showed >50% inhibition on 7/370 kinases, while ibr, acala, and M27 had more off-target binding (17, 15 and 23 kinases, respectively) at their respective 100X IC50 (BTK) concentrations (Figure 2). Conclusion: In pts with B-cell malignancies intolerant to ibr and/or acala, zanu treatment resulted in continued disease control or improved response. Zanu was well-tolerated, and most AEs that led to discontinuation of previous BTKi therapy did not recur or recurred at a lower grade. In support of clinical findings, differentiation between BTKi selectivity profiles favor zanu over ibr and acala. Figure 1 Figure 1. Disclosures Shadman: Abbvie, Genentech, AstraZeneca, Sound Biologics, Pharmacyclics, Beigene, Bristol Myers Squibb, Morphosys, TG Therapeutics, Innate Pharma, Kite Pharma, Adaptive Biotechnologies, Epizyme, Eli Lilly, and Atara Biotherapeutics, Adaptimmune: Consultancy; Mustang Bio, Celgene, Bristol Myers Squibb, Pharmacyclics, Gilead, Genentech, Abbvie, TG Therapeutics, Beigene, AstraZeneca, Sunesis, Atara Biotherapeutics, GenMab: Research Funding; Abbvie, Genentech, AstraZeneca, Sound Biologics, Pharmacyclics, Beigene, Bristol Myers Squibb, Morphosys, TG Therapeutics, Innate Pharma, Kite Pharma, Adaptive Biotechnologies, Epizyme, Eli Lilly, and Atara Biotherapeutics, Adaptimmune: Membership on an entity's Board of Directors or advisory committees. Flinn: Nurix Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Seagen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; MorphoSys: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Forty Seven: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Calithera Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Verastem: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Curis: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Takeda: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; IGM Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; AbbVie: Consultancy, Other: All Consultancy and Research Funding payments made to Sarah Cannon Research Institute, Research Funding; Portola Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Trillium Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Rhizen Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Incyte: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Acerta Pharma: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Agios: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Kite, a Gilead Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Gilead Sciences: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Karyopharm Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Forma Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Genentech: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; ArQule: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Triphase Research & Development Corp.: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Roche: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Pfizer: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Teva: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Infinity Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Unum Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Celgene: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Constellation Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Juno Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; AstraZeneca: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Iksuda Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Loxo: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Merck: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Novartis: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Great Point Partners: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; BeiGene: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Janssen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; TG Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Century Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Hutchison MediPharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Vincerx Pharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Sarah Cannon Research Institute: Current Employment; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Seagen: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Unum Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute, Research Funding; Johnson & Johnson: Current holder of individual stocks in a privately-held company; Seattle Genetics: Research Funding. Levy: Epizyme: Consultancy, Other: Promotional speaker; Amgen Inc.: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Gilead Sciences, Inc.: Consultancy, Honoraria, Speakers Bureau; GSK: Consultancy, Other: Promotional speaker; Morphosys: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; AbbVie: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Beigene: Consultancy, Honoraria, Speakers Bureau; Karyopharm: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Novartis: Consultancy, Other: Promotional speaker; Dova: Consultancy, Other: Promotional speaker; TG Therapeutics: Consultancy, Honoraria, Speakers Bureau; Bristol Myers Squibb: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Seattle Genetics: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau; Janssen Pharmaceuticals: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau. Burke: SeaGen: Consultancy, Speakers Bureau; Beigene: Consultancy, Speakers Bureau; MorphoSys: Consultancy; Bristol Myers Squibb: Consultancy; AstraZeneca: Consultancy; Epizyme: Consultancy; Verastem: Consultancy; Kura: Consultancy; Kymera: Consultancy; AbbVie: Consultancy; Adaptive Biotechnologies: Consultancy; Roche/Genentech: Consultancy; X4 Pharmaceuticals: Consultancy. Cultrera: Beigene: Research Funding. Yimer: Astrazeneca: Speakers Bureau; Karyopharm: Current equity holder in publicly-traded company, Speakers Bureau; Janssen: Speakers Bureau; Beigene: Speakers Bureau; GSK: Speakers Bureau; Sanofi: Speakers Bureau; Amgen: Speakers Bureau; Pharmacyclics: Speakers Bureau; Texas Oncology: Current Employment. Chaudhry: Medical Oncology Associates, PS (dba Summit Cancer Centers): Current Employment; Novartis, Immunomedics: Current holder of individual stocks in a privately-held company. Gandhi: TG Therapeutics: Honoraria; Karyopharm Therapeutics: Honoraria; GlaxoSmithKline: Honoraria. Kingsley: Comprehensive Cancer Centers of Nevada: Current Employment. Tumula: Texas Oncology: Current Employment. Manda: Morphosys: Honoraria; Genmab: Current equity holder in publicly-traded company. Chen: BeiGene: Current Employment, Divested equity in a private or publicly-traded company in the past 24 months. Cohen: BeiGene: Current Employment, Current equity holder in publicly-traded company, Other: Travel, Accommodations, Expenses. By: BeiGene, Ltd: Current Employment. Xu: Beigene: Current Employment; AstraZeneca: Ended employment in the past 24 months. Liu: BeiGene Co., Ltd: Current Employment, Current equity holder in publicly-traded company. Sharman: TG Therapeutics: Consultancy; Centessa: Current holder of stock options in a privately-held company, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics LLC, an AbbVie Company: Consultancy; BMS: Consultancy; AbbVie: Consultancy; BeiGene: Consultancy; AstraZeneca: Consultancy; Lilly: Consultancy.

Background: Umbralisib, a selective PI3Kδ and casein kinase-1epsilon (CK1ε) inhibitor, is pharmacologically distinct from other PI3K inhibitors and is administered orally once daily. Ublituximab is a novel anti-CD20 monoclonal antibody glycoengineered for enhanced antibody-dependent cellular cytotoxicity that targets a unique epitope on CD20. The primary analysis of the randomized, multicenter, Phase 3 UNITY-CLL trial (NCT02612311) demonstrated that the umbralisib+ublituximab (U2) combination prolonged progression-free survival (PFS) compared to chemoimmunotherapy in both treatment-naïve (TN) and previously treated (PT) populations (Gribben et al. 2020). Herein, results are presented for patients treated with U2 by treatment status. Methods: Patients ≥18 years of age with TN or PT CLL requiring treatment, per iwCLL criteria with adequate organ function and ECOG PS ≤2, were eligible. Patients were initially randomized 1:1:1:1 to receive U2, obinutuzumab+chlorambucil (O+Chl), umbralisib monotherapy, or ublituximab monotherapy. Stratification factors included treatment status (treatment-naïve vs. previously treated) and deletion 17p status. Umbralisib was administered orally at 800 mg once daily until progression or removal from treatment for other reasons. Ublituximab was administered intravenously at 900 mg on Days 1/2 [split 150/750 mg], 8, and 15 of Cycle 1, Day 1 of Cycles 2 - 6, and on Day 1 every 3 cycles after Cycle 6. The primary endpoint was independent review committee (IRC)-assessed PFS of U2 compared to O+Chl. Key secondary endpoints included IRC-assessed overall response rate (ORR), complete response, undetectable minimal residual disease (uMRD), duration of response, and safety, assessed from the first dose until 30 days after the last dose of study medication. While the primary analysis reported results for the pooled intent-to-treat population, the current analysis focuses on outcomes in patients treated with U2 by treatment status. Results: At data cut-off date of May 1, 2020, U2-treated patients had a median follow-up of 35.27 months. Of the 210 patients treated with U2, 119 were TN and 91 were PT. TN patients had a median age of 68 years (39 - 88 years) and 63% were male. Median PFS for U2 in TN patients was 38.5 mos (95% CI, 33.2, NE) with an estimated 24-mo PFS rate of 76.6%. IRC-assessed ORR was 84.0% (95% CI, 77.5%-90.6%). The median duration of exposure to umbralisib and ublituximab was 26.5 and 29.5 mos, respectively. In TN patients, AEs of special interest (AESI) of grade ≥3 included: neutropenia (24.1%), diarrhea (13.8%), ALT increased (12.1%), AST increased (7.8%), non-infectious colitis (2.6%), infusion-related reaction (IRR, 0.9%), and pneumonitis (0.9%). Discontinuation of either study drug due to these grade ≥3 AESI occurred in 5.2% (neutropenia), 2.6% (diarrhea), 3.4% (ALT increase), 1.7% (AST increase), 1.7% (colitis), 0.9% (IRR), and 0.9% (pneumonitis) of patients. PT patients had a median of 2 prior (1 - 9) lines of therapy, the median age was 65 years (43 - 87 years) and 65.9% were male. Median PFS was 19.5 mos (95% CI, 14.6-27.7) with an estimated 24-mo PFS rate of 41.3%. The IRC-assessed ORR was 82.4% (95% CI, 74.6%-90.2%). Among 14 patients previously treated with ibrutinib, the ORR was 57%. The median duration of exposure to umbralisib and ublituximab were 15.6 mos and 14.6 mos, respectively. In PT patients, AESI of grade ≥3 included: neutropenia (40.0%), diarrhea (10.0%), IRR (3.3%), ALT increase (3.3%), AST increase (2.2%), and non-infectious colitis (2.2%). Discontinuation of either study drug due to these grade ≥3 AESI occurred in 1.1% (ALT increase), 1.1% (AST increase), and 1.1% (colitis) of patients. Conclusions: U2 demonstrated a tolerable safety profile in both the TN and PT populations. These results mark the first randomized Phase 3 trial of a PI3K in TN CLL, establishing a new mechanism of action in this setting. Disclosures Jacobs: Genentech: Consultancy; Jannsen: Speakers Bureau; TG Therapeutics: Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding, Speakers Bureau; Verastem: Consultancy; AbbVie: Consultancy, Speakers Bureau; SecuraBio: Consultancy, Speakers Bureau; TeneoBio: Research Funding; MEI Pharma: Research Funding; Adaptive Biotechnologies: Consultancy; ADC Therapeutics: Consultancy. Jurczak: Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk: Research Funding; Morphosys: Research Funding; Mei Pharma: Research Funding; Merck: Research Funding; Loxo Oncology: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Research Funding; Epizyme: Research Funding; Debbiopharm: Research Funding; Celgene: Research Funding; Celtrion: Research Funding; BeiGene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Research Funding; Sandoz: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Research Funding; TG Therapeutics: Research Funding. Flinn: ArQule: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Loxo: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Gilead Sciences: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Constellation Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; MorphoSys: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Infinity Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Kite, a Gilead Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Acerta Pharma: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Agios: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Seagen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; AbbVie: Consultancy, Other: All Consultancy and Research Funding payments made to Sarah Cannon Research Institute, Research Funding; Nurix Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Celgene: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Curis: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Juno Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Incyte: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Verastem: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Forma Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Forty Seven: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Iksuda Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Great Point Partners: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Unum Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Karyopharm Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Genentech: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; BeiGene: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; AstraZeneca: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Novartis: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Takeda: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Calithera Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Portola Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Janssen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; IGM Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Pfizer: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; TG Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Merck: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Roche: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Rhizen Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Teva: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Trillium Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Triphase Research & Development Corp.: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Century Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Hutchison MediPharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Vincerx Pharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Sarah Cannon Research Institute: Current Employment; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Seagen: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Unum Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute, Research Funding; Johnson & Johnson: Current holder of individual stocks in a privately-held company; Seattle Genetics: Research Funding. Giannopoulos: Sandoz: Consultancy, Honoraria; Pfizer: Honoraria; Teva: Honoraria; Karyopharm: Consultancy, Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Bei-Gene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Astra-Zeneca: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; TG Therapeutics: Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; GSK: Consultancy, Honoraria, Research Funding; Polish Myeloma Consortium, Next Generation Hematology Association: Membership on an entity's Board of Directors or advisory committees; Sanofi-Genzyme: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding. Wróbel: Novartis: Honoraria, Speakers Bureau; BMS: Honoraria; Roche: Honoraria, Research Funding, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; BeiGene: Honoraria. Cultrera: Beigene: Research Funding. Danilov: Gilead Sciences: Research Funding; Bristol-Meyers-Squibb: Honoraria, Research Funding; Takeda Oncology: Research Funding; TG Therapeutics: Consultancy, Research Funding; Abbvie: Consultancy, Honoraria; Beigene: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; Rigel Pharm: Honoraria; Bayer Oncology: Consultancy, Honoraria, Research Funding; Astra Zeneca: Consultancy, Honoraria, Research Funding; SecuraBio: Research Funding; Genentech: Consultancy, Honoraria, Research Funding. Burke: Kymera: Consultancy; Adaptive Biotechnologies: Consultancy; Beigene: Consultancy, Speakers Bureau; Epizyme: Consultancy; AbbVie: Consultancy; MorphoSys: Consultancy; Verastem: Consultancy; Bristol Myers Squibb: Consultancy; Kura: Consultancy; Roche/Genentech: Consultancy; AstraZeneca: Consultancy; SeaGen: Consultancy, Speakers Bureau; X4 Pharmaceuticals: Consultancy. Goldschmidt: Ontada: Current Employment; Blue Ridge Cancer Care: Current Employment; Amgen: Honoraria, Speakers Bureau; BMS: Honoraria, Speakers Bureau; TG Therapeutics: Honoraria; G1 Therapeutics: Honoraria, Speakers Bureau. Beach: TG Therapeutics: Speakers Bureau. Huntington: TG Therapeutics: Research Funding; DTRM Biopharm: Research Funding; AbbVie: Consultancy; AstraZeneca: Consultancy, Honoraria; Flatiron Health Inc.: Consultancy; Bayer: Honoraria; Servier: Consultancy; Genentech: Consultancy; Novartis: Consultancy; Thyme Inc: Consultancy; SeaGen: Consultancy; Pharmacyclics: Consultancy, Honoraria; Celgene: Consultancy, Research Funding. Pinilla Ibarz: Sellas: Other: ), patents/royalties/other intellectual property; AbbVie, Janssen, AstraZeneca, Takeda: Speakers Bureau; AbbVie, Janssen, AstraZeneca, Novartis, TG Therapeutics, Takeda: Consultancy, Other: Advisory; MEI, Sunesis: Research Funding. Sharman: TG Therapeutics: Consultancy; Pharmacyclics LLC, an AbbVie Company: Consultancy; BeiGene: Consultancy; AstraZeneca: Consultancy; Centessa: Current holder of stock options in a privately-held company, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy; Lilly: Consultancy; AbbVie: Consultancy. Siddiqi: AstraZeneca: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees; Juno therapeutics: Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; BeiGene: Other: DSM Member, Speakers Bureau; PCYC: Speakers Bureau; Jannsen: Speakers Bureau; Dava Oncology: Honoraria; ResearchToPractice: Honoraria. Brander: Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; AstraZeneca: Research Funding; ArQule: Research Funding; DTRM: Research Funding; Ascentage: Research Funding; Genentech: Consultancy, Research Funding; Novartis: Research Funding; TG Therapeutics: Consultancy, Research Funding; AbbVie: Consultancy, Other: informCLL registry steering committee, Research Funding; Verastem: Consultancy; MEI Pharma: Research Funding; LOXO: Research Funding; NCCN: Other: panel member; ArQule/Merck: Consultancy; Juno Therapeutics/Celgene/Bristol Myers Squibb: Research Funding; BeiGene: Research Funding; Pfizer: Consultancy, Other: Biosimilars outcomes research panel. Shadman: Abbvie, Genentech, AstraZeneca, Sound Biologics, Pharmacyclics, Beigene, Bristol Myers Squibb, Morphosys, TG Therapeutics, Innate Pharma, Kite Pharma, Adaptive Biotechnologies, Epizyme, Eli Lilly, Adaptimmune , Mustang Bio and Atara Biotherapeutics: Consultancy; Mustang Bio, Celgene, Bristol Myers Squibb, Pharmacyclics, Gilead, Genentech, Abbvie, TG Therapeutics, Beigene, AstraZeneca, Sunesis, Atara Biotherapeutics, GenMab: Research Funding. Pagel: AstraZeneca: Consultancy; Gilead: Consultancy; Pharmacyclics/AbbVie: Consultancy; Incyte/MorphoSys: Consultancy; Actinium Pharmaceuticals: Consultancy; Kite, a Gilead Company: Consultancy; MEI Pharma: Consultancy; Epizyme: Consultancy; BeiGene: Consultancy. Dlugosz-Danecka: Janssen: Consultancy, Research Funding; Roche: Consultancy, Research Funding, Speakers Bureau; Servier: Consultancy, Speakers Bureau; Acerta Pharma: Research Funding; AbbVie: Research Funding; Macrogenics: Research Funding; Beigene: Research Funding; MEI Pharma: Research Funding; Incyte Corp.: Research Funding; Takeda: Research Funding. Ghosh: Janssen: Consultancy, Honoraria, Speakers Bureau; Incyte: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding, Speakers Bureau; ADC Therapeutics: Consultancy, Honoraria; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; TG Therapeutics: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Speakers Bureau; Karyopharma: Consultancy, Honoraria; Genentech: Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; Epizyme: Honoraria, Speakers Bureau; Genmab: Consultancy, Honoraria; Adaptive Biotech: Consultancy, Honoraria; AbbVie: Honoraria, Speakers Bureau. Kolibaba: TG Therapeutics: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Atara Biotechm: Consultancy; McKesson Specialty Health: Consultancy; Sunitomo Dainippon Pharma: Consultancy; Tolero Pharma: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Sportelli: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Miskin: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. O'Connor: Mundipharma: Consultancy; Nomocan: Consultancy; Kymera: Consultancy, Current equity holder in publicly-traded company; TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company; Dren: Consultancy, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Myeloid Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Weiss: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Gribben: Takeda: Honoraria; Novartis: Honoraria; Morphosys: Honoraria; Gilead/Kite: Honoraria; BMS: Honoraria; Abbvie: Honoraria; AZ: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; TG Therapeutics: Honoraria.

Background: Bruton tyrosine kinase (BTK) inhibitors (BTKi) have been shown to improve outcomes in patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL); however, adverse events (AEs) were the most common reason for ibrutinib and acalabrutinib discontinuation (median time ≤6 mo; Mato et al, Haematologica 2018;103:874; Yazdy et al, Blood 2019; Supplement1: 4311). Off-target effects of ibrutinib have been implicated in BTKi-related AEs. Zanubrutinib, a BTKi approved for treatment of mantle cell lymphoma (MCL) and in development for other hematologic malignancies, was specifically engineered to optimize selectivity and maximize BTK occupancy. In the head-to-head ASPEN trial of zanubrutinib vs ibrutinib in patients with Waldenström macroglobulinemia (WM), zanubrutinib showed a lower rate of AEs leading to death, discontinuation, dose reduction, and dose holds (Dimopoulos et al, EHA 2020; Abstract S225). We conducted a prospective clinical trial of zanubrutinib in patients with relapsed/refractory B-cell malignancies who have become intolerant to prior BTKi (ibrutinib and/or acalabrutinib) therapy. Methods : In this ongoing phase 2, multicenter, US, single-arm, open-label study (NCT04116437; BGB-3111-215), the safety and efficacy of zanubrutinib monotherapy (160 mg twice daily or 320 mg once daily) is being evaluated in patients with B-cell malignancies who meet requirements for treatment and have become intolerant to prior BTKi therapy. An intolerant event was defined as an unacceptable toxicity where, in the opinion of the investigator (INV), treatment should be discontinued despite optimal supportive care as a result of 1 of the following: grade ≥2 nonhematologic toxicities for >7 days (with or without treatment), grade ≥3 nonhematologic toxicity of any duration, grade 3 neutropenia with infection or fever, or grade 4 hematologic toxicity that persists to the point that the INV chose to stop therapy due to toxicity and not disease progression (PD). All enrolled patients must not have documented PD during prior BTKi therapy. Response assessment was evaluated by INV for CLL per modified International Workshop on CLL criteria (Hallek et al, Blood 2008;131:2745; Cheson et al, J Clin Oncol 2012;30:2820), for SLL, MCL, and marginal zone lymphoma per Lugano criteria (Cheson et al, J Clin Oncol 2014;32:3059), and for WM per modified 6th International Workshop on WM criteria (Owen et al, Br J Haemtol 2013;160:171). Disease parameters (imaging and laboratory parameters) performed at study entry were used as the baseline for response assessment. Results : As of 01 June 2020 (data cutoff), 17 patients with CLL/SLL were enrolled, received ≥1 dose of zanubrutinib, and were analyzed for safety. Median age was 70 years (range, 49-91) and median duration of treatment exposure was 3.02 mo (range, 0.56-7.59). The median number of prior regimens was 1 (range, 1-3). All patients had received ibrutinib. At data cut off, no patients had received acalabrutinib. At data cutoff, 16 patients remained on zanubrutinib treatment. One patient withdrew herself from the study following an AE (grade 3 syncope) unrelated, as per INV, to study treatment. Of the 31 BTKi-related AEs associated with intolerance (Table 1), 30 (96.8%) did not recur, and 1 event (3.2%; atrial fibrillation) recurred at a lower grade (grade 3 vs 2) and for a shorter duration (14 vs 3 days) vs the initial ibrutinib-intolerant event. Ten patients (58.8%) reported ≥1 AE. AEs reported in ≥10% of patients on zanubrutinib included dizziness (n=3; 17.6%) and cough (n=2; 11.8%). Grade ≥3 AEs were reported in 2 patients (11.8%): neutropenia and syncope (n=1 each; 5.9%). AEs of interest included hemorrhage and infections (n=3 each, 17.6%) and anemia, neutropenia, and atrial fibrillation (n=1 each; 5.9%). No AEs led to dose modification or treatment discontinuation. No serious AEs or deaths were reported. As of data cutoff, 10 patients were evaluable for efficacy with ≥1 response assessment. All 10 patients achieved at least stable disease, and 60% of these patients achieved a deepening of response since initiating zanubrutinib. Enrollment is ongoing and the presentation will include additional patients. Conclusions : Zanubrutinib demonstrated efficacy and tolerability in CLL/SLL patients who were intolerant to previous BTKi. These data suggest that zanubrutinib may provide a potential option after intolerance to other BTKi. Disclosures Shadman: Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; ADC Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BeiGene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; Atara Biotherapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Cellectar: Consultancy, Membership on an entity's Board of Directors or advisory committees; Verastem: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol Meyers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; TG therapeutics: Research Funding; Sound Biologics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Mustang Bio: Research Funding; MophoSys: Consultancy, Membership on an entity's Board of Directors or advisory committees; Acerta Pharma: Ended employment in the past 24 months; Sunesis: Research Funding; Gilead: Research Funding. Sharman:Celgene: Consultancy, Research Funding; Bristol Meyers Squibb: Consultancy, Research Funding; BeiGene: Research Funding; Roche: Consultancy, Research Funding; Acerta: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding. Levy:Amgen: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding; Bristol Meyers Squibb: Consultancy, Honoraria, Research Funding; BeiGene: Consultancy, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Research Funding; Baylor University Med Center: Current Employment; Takeda: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding. Misleh:Medical Oncology Hematology Consultants (MOHC): Current Employment; High Mark Blue Cross: Membership on an entity's Board of Directors or advisory committees. Zafar:Bristol Meyers Squibb: Honoraria, Other: TRAVEL, ACCOMODATIONS, EXPENSES (paid by any for-profit health care company); AstraZeneca: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Karyopharm: Honoraria; Sarah Canon Research Institute: Research Funding; Florida Cancer Specialists and Research Institute: Current Employment. Freeman:Summit Medical Group: Current Employment. Burke:Kura: Consultancy; Celgene: Consultancy; Gilead: Consultancy; Adaptive: Consultancy; Morphosys: Consultancy; Bristol Myers Squibb: Consultancy; Roche: Consultancy; AbbVie: Consultancy; Bayer: Consultancy; Astra Zeneca: Consultancy; Verastem: Consultancy; Epizyme: Consultancy; Seattle Genetics: Speakers Bureau; Adaptive Biotechnologies: Consultancy. Cultrera:Amgen: Speakers Bureau; Florida Cancer Specialists + Research Institute: Current Employment; Celgene: Speakers Bureau; AcroTech: Speakers Bureau; Verastem: Speakers Bureau. Yimer:BeiGene: Other: TRAVEL, ACCOMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding, Speakers Bureau; Takeda: Speakers Bureau; Sanofi: Speakers Bureau; Epizyme: Consultancy, Divested equity in a private or publicly-traded company in the past 24 months; Texas Oncology: Current Employment; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Speakers Bureau; Karyopharm: Consultancy, Divested equity in a private or publicly-traded company in the past 24 months, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Speakers Bureau; TG Therapeutics: Consultancy; Janssen: Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding, Speakers Bureau; Celgene, a Bristol-Myers Squibb Company: Consultancy, Membership on an entity's Board of Directors or advisory committees. Chen:BeiGene: Current Employment, Current equity holder in publicly-traded company. Zhang:BeiGene: Current Employment, Current equity holder in publicly-traded company, Divested equity in a private or publicly-traded company in the past 24 months. Cohen:BeiGene: Current Employment, Current equity holder in publicly-traded company, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Ro:BeiGene: Current Employment, Current equity holder in publicly-traded company; Amgen: Current equity holder in publicly-traded company. Huang:BeiGene: Current Employment, Current equity holder in publicly-traded company, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Flinn:Iksuda Therapeutics: Consultancy; Loxo: Research Funding; Kite Pharma: Consultancy, Research Funding; Karyopharm Therapeutics: Research Funding; IGM Biosciences: Research Funding; Infinity Pharmaceuticals: Research Funding; Unum Therapeutics: Consultancy, Research Funding; Juno Therapeutics: Consultancy, Research Funding; Acerta Pharma: Research Funding; Incyte: Research Funding; Janssen: Consultancy, Research Funding; Great Point Partners: Consultancy; Genentech, Inc.: Research Funding; AstraZeneca: Consultancy, Research Funding; ArQule: Research Funding; Agios: Research Funding; Takeda: Consultancy, Research Funding; Forty Seven: Research Funding; Calithera Biosciences: Research Funding; BeiGene: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; Trillium Therapeutics: Research Funding; Triphase Research & Development Corp.: Research Funding; Verastem: Consultancy, Research Funding; Yingli Pharmaceuticals ≠: Consultancy, Research Funding; Rhizen Pharmaceuticals: Research Funding; Johnson & Johnson: Other; Roche: Consultancy, Research Funding; Vincera Pharma: Consultancy; Celgene: Research Funding; Merck: Research Funding; Constellation Pharmaceuticals: Research Funding; Curio Science: Consultancy; MorphoSys: Consultancy, Research Funding; Curis: Research Funding; AbbVie: Consultancy, Research Funding; Teva: Research Funding; Pfizer: Research Funding; Nurix Therapeutics: Consultancy; Novartis: Research Funding; Seattle Genetics: Consultancy, Research Funding; Portola Pharmaceuticals: Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; Forma Therapeutics: Research Funding; F. Hoffmann-La Roche: Research Funding; Gilead Sciences: Consultancy, Research Funding. OffLabel Disclosure: Zanubrutinib has not been approved for R/R CLL/SLL, MZL, and WM in the US

e19506 Background: Many patients (pts) with B-cell malignancies require continuous treatment with Bruton tyrosine kinase inhibitors (BTKi). Adverse events (AEs) are a common reason for ibrutinib (ibr) or acalabrutinib (acala) discontinuation. Early data from BGB-3111-215 showed zanubrutinib (zanu) was well tolerated in pts with B-cell malignancies intolerant to ibr or acala. We report preliminary results with a median follow-up of 4.2 mo. Methods: Pts meeting protocol criteria for intolerance to ibr, acala or both (without documented progressive disease) were given zanu monotherapy (160 mg twice daily or 320 mg once daily). Recurrence of AEs that led to intolerance of prior BTKi and additional safety measures were assessed based on the Common Terminology Criteria for AEs v5.0. Investigators determined responses using disease status at study entry as baseline. Results: As of November 1, 2020 (cutoff), 44 pts (n=34 chronic lymphocytic leukemia/small lymphocytic lymphoma, n=6 Waldenström macroglobulinemia, n=2 mantle cell lymphoma, n=2 marginal zone lymphoma) were enrolled, received ≥1 dose of zanu, and analyzed for safety. Median age was 70.5 y (range, 49-91); median duration of treatment was 4.2 mo (range, 0.1-12.6). Median number of prior regimens was 2 (range, 1-12). Regarding prior BTKi, 39 pts received ibr only, 4 received ibr and acala, and 1 received acala only. The median number of ibr- or acala-intolerant AEs per pt was 2 (range, 1-5). 83% of ibr and 78% of acala intolerant events did not reccur on zanu; Table. At data cutoff, 43 pts remained on treatment; 1 withdrew consent due to zanu-unrelated grade 3 syncope. Overall, 34 pts (77.3%) reported any AE; most commonly reported AEs were myalgia (n=9; 20.5%), contusion (n=8; 18.2%), dizziness (n=7; 15.9%), fatigue (n=7; 15.9%), and cough (n=5; 11.4%). Grade ≥3 AEs were reported in 6 pts (13.6%), serious AEs in 1 pt (2.3%, febrile neutropenia and salmonella infection), AEs requiring dose interruptions in 6 pts (13.6%), and AEs leading to dose reduction in 2 pts (4.5%). No AEs led to zanu discontinuation. No deaths were reported. All efficacy evaluable pts (26/26 [100%]) maintained (10 [38.5%]) or achieved deepening (16 [61.5%]) of their response. Conclusions: Zanu provides an additional treatment option after intolerance to other BTKi, demonstrating tolerability and sustained or improved efficacy. Updated results will be presented. Recurrence and Severity Change of AEs Leading to Ibr or Acala Intolerance. Clinical trial information: NCT04116437. [Table: see text]

5009 Background: Preclinical and phase 1 results suggest PI3K/mTOR pathway inhibition may enhance androgen receptor inhibition. We report the results of a double-blind, placebo-controlled, randomized Phase 1b/2 study of ENZ±LY (a dual PI3K/mTOR inhibitor) in pts with mCRPC who progressed on abiraterone. Methods: Phase 1b pts received single-agent LY 200 mg twice daily (BID) for 1 wk prior to starting LY+ENZ. Phase 2 pts were randomized 1:1 to 160 mg daily ENZ with PL or 200 mg BID LY on a 28-d cycle. The primary objective was progression-free survival (PFS: serological, radiographic [rPFS], or death) by PCWG2 criteria. Secondary objectives were rPFS, safety, decline in PSA, and PK. Exploratory biomarker analyses included outcomes by presence of androgen receptor variant 7 (AR-V7). 92 primary PFS events were needed for the study to have at least 80% power at one-sided alpha=0.20. Results: LY+ENZ was tolerable during Phase 1b with 1 dose limiting toxicity observed in 13 enrolled pts. Mean LY exposures remained in an efficacious range despite a 30% average decrease when combined with ENZ. In Phase 2, 129 pts were randomized to LY+ENZ (N=65) and PL+ENZ (N=64) (Table). Median PCWG2-PFS was 3.7 mos (LY+ENZ) vs 2.9 mos (PL+ENZ) (HR 0.66, 95% CI 0.43, 0.99; p-value 0.0208). Conclusions: Combination LY+ENZ had a clinically manageable safety profile. The primary end-point of PCWG2-PFS was met and is supported by a clinically meaningful delay in rPFS in AR-V7 negative pts. The biomarker data provide important insights to inform future development strategies. Clinical trial information: NCT02407054. [Table: see text]

Diffuse large B-cell lymphoma (DLBCL) is the most common histology of non-Hodgkin lymphoma, representing 25% to 35% of new cases annually. The incidence of DLBCL has doubled in the past decades, highlighting the need for more effective treatment regimens.This article reviews the current protocols applicable to this aggressive lymphoma and discusses ongoing research that is focusing on molecular diagnostics, prognostic factors have also been defined for DLBCL.Patients with DLBCL vary in clinical presentation, prognosis, and response to current therapies. While current therapy in the rituximab era has led to improved outcomes with reduced toxicity, novel treatment approaches for localized, advanced, and relapsed/refractory DLBCL are being pursued in clinical trials. Several studies have shown promise, such as trials involving proteasome inhibitors, lenalidomide, and antibody drug conjugates.Recent discoveries in the spectrum of care for patients with DLBCL have prompted a renaissance for personalized cancer medicine and molecularly targeted therapy. Potential targets and novel drug combinations are undergoing continued study in the hope of achieving successful and personalized care of this disease.

Plasmablastic lymphoma (PBL) is a rare aggressive B-cell lymphoproliferative disorder. HIV-negative PBL has not been extensively reported. Nine HIV-negative PBL patients evaluated at Moffitt Cancer Center were studied. Eight patients had extranodal diseases. All patients were treated with CHOP or hyper-CVAD. Responses were observed in 8 cases (7 complete, 1 partial responses). Four patients underwent consolidation with autologous hematopoietic stem cell transplant (HSCT) in first complete remission (CR1). At median follow-up of 23.9 months, 7 patients were alive and 5 were disease-free. Aggressive induction chemotherapy and consolidation with autologous HSCT in CR1 might be considered for patients with HIV-negative PBL.

382 Background: Carfilzomib (CFZ) is an irreversible proteasome inhibitor (PI) that exhibits anti-proliferative and pro-apoptotic activity in solid and hematologic tumor cells i n vitro, and is US FDA approved for multiple myeloma. Proteasomes degrade cell cycle inhibitor proteins and inhibition of these proteins offers a novel therapy for the treatment of patients with neuroendocrine tumors (NET). This phase 2 study evaluated the efficacy of CFZ for patients with advance NETs. Methods: Pts with biopsy-proven, advanced, well-to-moderately differentiated NETs, including typical carcinoid and pancreatic islet cell tumors, were treated with CFZ 20 mg/m2 IV Days (D) 1 and 2, then 56 mg/m2 IV D 8, 9, 15, and 16 of Cycle (C) 1, followed by CZF 56 mg/m2 IV D 1, 2, 8, 9, 15, and 16 of C 2 and beyond. Pts continued study treatment (tx) until intolerable toxicity, disease progression, or withdrawal of consent. Restaging occurred every 3 cycles. The primary endpoint was overall response rate (ORR); secondary endpoints were disease control rate (DCR), progression free survival (PFS), and toxicity. Results: 62 pts were enrolled: median age 63 yrs, 61% female, 50% ECOG 0/50% ECOG 1. 65% of pts had carcinoid tumors and 35% of pts had pancreatic NET. The most common primary sites of disease were the pancreas (34%) and the small intestines (21%). 74% of pts had prior systemic therapy, 42% had prior surgery and 16% had prior radiotherapy. Median tx duration was 11 wks. At the time of data cutoff, 31% of pts remained on tx. 32% of pts discontinued due to progressive disease, 16% due AE, and 21% due to pt or physician decision. Two pts (3%) had a confirmed partial response (PR) and 1 pt (2%) had an unconfirmed PR; 4 ongoing patients have not yet been evaluated for response. The ORR was 3.23% (95% CI 0.4%, 11.2%), the DCR was 53.23% (CI 95% 40.1%, 66.0%), and median PFS was 8.1 months. The most frequently reported tx-related AEs were nausea (52%; Grade 3/4 [G3/4], 2%), fatigue (42%; G3/4, 3%), vomiting (36%; G3/4, 2%), and diarrhea (27%; G3/4, 5%). Conclusions: CFZ tx was well-tolerated in this pt population. Future plans will be determined once response data are available on all patients. Updated results will be presented. Clinical trial information: NCT02318784.

e18555Background: MDS is a heterogeneous group of clonal acquired hematologic disorders which is prevalent in the elderly population. Despite an intensive prognostic scoring system (IPSS-R) there a...

Abstract 4546 Introduction: Consolidation with autologous transplantation (AutoSCT) may extend progression free survival when administered following initial induction. Published data suggest intensive cytarabine containing induction may improve outcome when administered prior to autologous transplantation. Methods: We retrospectively evaluated all patients with MCL transplanted at our institution before 2010. We identified 57 patients, among whom 52 were transplanted in first or second remission. Results: 21 patients had received a cytarabine containing induction (most commonly R-HyperCVAD), among whom 14 also received cytarabine as a component of conditioning (BEAM+/−R). The most common induction in the remaining patients was R-CHOP. Among the 31 who did not receive a cytarabine based induction, 23 received cytarabine as a component of the pre-transplant conditioning regimen (BEAM+/−R). The median PFS for those getting cytarbine with induction and conditioning was approximately 28 months (at which time 51% of patients continued without progression). The median PFS for those getting cytarabine with conditioning only was approximately 38 months (at which time 47% continued without progression). Logrank analysis shows no statistically significant difference between these groups (p one-sided = 0.29). Alternatively, those who did not receive any cytarabine had a median PFS of 20 months, with no survival beyond 33 months. Logrank analysis shows this to be inferior to those receiving cytarabine with induction/conditioning (p one-sided = 0.049), as well as among those who received cytarabine with conditioning only (p one-sided = 0.001). Conclusions: In the absence of randomized comparisons it is difficult to draw firm conclusions on the role of induction. These analyses would suggest that among those with chemosensitive disease able to proceed to transplant, more modern conditioning with cytarabine containing regimens may make up for lack of exposure to this agent during induction. Disclosures: Sokol: Celgene: Honoraria, Speakers Bureau.

Abstract 5082 Introduction: Retrospective analyses suggest an improved outcome for patients with mantle cell lymphoma (MCL) in whom safe watchful waiting can be employed. We explored our own cohort of patients treated at the H Lee Moffitt Cancer Center in an effort to validate these data. Methods: We retrospectively identified 280 patients with MCL treated at our institution, for whom treatment data are available among 260. Patients were stratified according to whether they were treated within 3 months, within 3–12 months, and beyond 12 months. Treatment includes radiation, surgery, chemotherapy, immunotherapy, or any combination there-of. Median overall survival (OS) is calculated from date of diagnosis to death. Median progression free survival (PFS) is calculated from time of treatment start to progression or death. Results: Of 260 evaluable patients 191 were treated within 3 months of diagnosis, 33 were treated between 3–12mo, and 36 had received no treatment beyond one year. The median OS for each group were approximately 62mo, 74mo, and 130mo, respectively (Figure 1A). Median PFS following treatment initiation was nearly indistinguishable between the three groups, at approximately 24mo, 26mo, and 19mo, respectively (Figure 1B). Conclusions: Time to treatment of greater than 12 months may identify those with a more indolent course. However, once treatment is required, patients appear to experience similar treatment benefit. Disclosures: No relevant conflicts of interest to declare.

Abstract 4885 Background: B cell lymphoma, unclassifiable, with features intermediate between diffuse large B cell lymphoma (DLBCL) and Burkitt lymphoma (BL) or Burkitt like lymphoma is a high grade lymphoma, with a high proliferation index and a complex karyotype mostly involving MYC and BCL-2 genes, so called “double hit” as well as BCL-6 genes, so called “triple hit”. This high grade lymphoma shows an aggressive behavior for which the most appropriate therapeutic approach is not established. Methods: This was a single center retrospective review of patients with a confirmed diagnosis of B cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL from 2006 to 2012. The definitive diagnosis in all cases was based on morphological and phenotypic features, and genetic abnormalities involving MYC, BCL-2, and BCL-6. Clinicopathological data was extracted including age, gender, primary disease location, phenotypic subtype, genetic abnormalities by FISH, IPI scores, treatment regimens and survival data. Descriptive statistical analyses were utilized. Kaplan-Meier method was used to estimate OS and log rank test was used to compare the groups. All data were analyzed using SPSS version 19.0 statistical software. Results: 31 patients with “Double or Triple Hit” lymphomas were identified between 2006 and 2012. The age range at diagnosis was 33–87 years with median age of 71. 23 of 31 patients (74 %) were ≥ 60 years old. Male to female ratio was 1.58:1 (19:12). The median ECOG PS was 1. No patients had HIV. A majority of patients presented with extranodal disease 21 out of 31 patients and only 10 patients presented with nodal disease. The mean overall survival of the entire cohort was 28 months with ranges 3 to 40 months. 20 of 31 patients (65%) are currently alive. RCHOP was the most utilized treatment regimen in the cohort of alive patients 13 out of 20 patients (65%). Patients who presented with CNS disease had a worse prognosis when compared to the entire cohort with a mean overall survival of 13 months versus non CNS disease overall survival was 32 months (p=0.014). In patients treated with RCHOP for first line therapy the overall survival was 33 months versus 17 months for non RCHOP regimens first line (p=.048). The non RCHOP regimens included Hyper CVAD, ESHAP, and RICE. Conclusions: RCHOP was the most utilized treatment regimen in the cohort of alive patients. The treatment regimen with the best efficacy in this retrospective study was RCHOP in first line treatment of “Double or Triple Hit” lymphomas. CNS disease is associated with worse prognosis in patients with “Double or Triple Hit” lymphomas in this retrospective study. Disclosures: No relevant conflicts of interest to declare.

Abstract 4858 Background Primary central nervous system lymphoma (PCNSL) is a rare aggressive variant of diffuse large B cell lymphoma (DLBCL) with a poor prognosis. Optimal therapeutic strategies have not been defined yet in primary CNS lymphoma. High dose Methotrexate (HD MTX) is an effective chemotherapeutic agent with superior outcomes compared to historical studies using whole brain radiation therapy (WBRT). The combination of HD MTX with WBRT showed improved response rates compared to chemotherapy (CT) alone, but was associated with greater risk of neurotoxicity in patients >60 years old. Purpose To review clinicopathologic characteristics, therapy and outcomes of 59 patients with primary CNS DLBCL without HIV. Methods This was a single center retrospective review of pts with confirmed diagnosis of primary CNS DLBCL from 1999 to 2012. Data was extracted from the Moffitt Cancer Center (MCC) electronic records. Baseline demographics, clinical, pathological and treatment data were collected and analyzed. Patients were stratified according to their treatment regimens including HD MTX (3g/m2) alone or in combinations and WBRT alone or in combination with CT. Descriptive statistical analyses were utilized. Chi square analysis and t- test were performed to compare categorical and continuous variables. Kaplan-Meier method was used to estimate OS and log rank test was used to compare the groups. All data was analyzed using SPSS version 19.0 statistical software. Results 59 patients who underwent CT and/or WBRT for PCNSL between 1999 and 2012 were identified. The age range at diagnosis was 17–85 years with median age of 64. 35 of 59 patients (59%) were ≥ 60 years old. Male to female ratio was 1.27:1 (33:26). The median ECOG PS was 1. A majority of patients presented with motor deficits, 29 out of 59. The most common location of lymphoma was in the cerebral hemispheres. The median survival of the entire cohort was 37 months. 18 of 59 pts (25%) survived ≥ 60 months. In the cohort of pts that survived ≥ 60 months, a majority 16 of 18 (89%) received HD MTX. Patients treated with initial WBRT and chemotherapy revealed inferior overall survival (OS) compare to patients treated with induction chemotherapy alone (OS 37 months vs. 66 months) (p=0.011). Patients over the age of 60 had worse outcomes compared to patients who were less than the age of 60 (OS 33 months versus 70 months) (p=0.023). Conclusions HD MTX was the most frequently utilized CT regimen in the cohort of patients surviving > 60 months. Administering WBRT combined with chemotherapy was associated with worse outcomes in this retrospective analysis. Patients with primary CNS lymphoma who are older than 60 have worse outcomes in this retrospective analysis compared to patients younger than 60. Disclosures: Sokol: Celgene: Honoraria, Speakers Bureau.

e18503 Background: The initial clinical presentation of Mantle Cell Lymphoma is protean, ranging from single sites of indolent disease followed for years without therapy to aggressive disseminated disease that requires treatment within weeks of diagnosis. While many cases of Mantle Cell Lymphoma present with disseminated disease, other patients may present with symptoms related to a primary extranodal site of disease. The majority of these primary extranodal cases are diagnosed in the gastrointestinal tract, other cases have been noted in the skin, conjunctiva, testes and male genitourinary tract. Methods: Database review of 204 patients diagnosed with Mantle Cell Lymphoma at Moffitt Cancer Center between May 1992 and December 2010. Results: Three cases of Mantle Cell Lymphoma presented with symptoms related to primary extranodal sites in the urinary tract and male genital organs. Two cases of testicular involvement presented with gradual enlargement of the testes. In patient 1, the orchiectomy specimen harbored both seminoma and mantle cell lymphoma. Low level bone marrow involvement by mantle cell lymphoma was present and in the presence of indolent features he was treated for his primary seminoma and followed expectantly for mantle cell lymphoma. In patient 2, orchiectomy revealed a pleomorphic variant of mantle cell lymphoma with no other sites of disease on staging workup. He was treated with 6 cycles of R-CHOP and prophylactic IT methotrexate with a complete remission. A third patient presented with obstructive urinary symptoms and was found to have mantle cell lymphoma of the prostate. Additional staging revealed diffuse lymphadenopathy, colon and bone marrow involvement. A complete remission was obtained with 6 cycles of R-CHOP. None of these three patients was found to have evidence of CNS involvement at diagnosis or in followup with only the second patient receiving intrathecal prophylaxis. Conclusions: Mantle Cell Lymphoma may present with unusual extranodal involvement at diagnosis including sites and symptoms related to the genitourinary tract and testes. Diagnostic lumbar puncture and intrathecal prophylaxis should be considered in these patients.

e18506 Background: In-Situ Mantle Cell Lymphoma is a rare clinical entity that presents with involvement limited to the mantle zone of secondary follicles. Its true incidence may be underestimated and its natural history and clinical behavior remains poorly characterized given the small number of representative cases available in the literature. Current guidelines for patients diagnosed with In-Situ Mantle Cell Lymphoma advocate staging studies and close follow-up with treatment based on the clinical behavior of the disease. Methods: Database review of 204 patients diagnosed with Mantle Cell Lymphoma at Moffitt Cancer Center between May 1992 and December 2010 Results: Three cases of In-Situ Mantle Cell Lymphoma were found and analyzed. Patients 1 & 2 had disease isolated to a single lymph node at diagnosis. In these cases, there were long latency periods of 5 and 9 years between initial resection of a single nodal site and later presentation with active, diffuse disease. Neither patient received therapy until progression with more advanced disease. Patient 2, who had a 9-year latency period was found to have complex cytogenetics suggesting evolution of the malignant clone during this prolonged latency period. Patient 3 presented with in situ disease in an inguinal node in conjunction with diffuse extranodal lung and forehead involvement, all noted at the time of diagnosis. Patient 1 obtained remission with Bendamustine & Rituxamab. Patient 2 obtained remission with HyperCVAD and Autologous HSCT consolidation. Patient 3 obtained remission after R-CHOP. Patients 1 & 2, both with long latency periods remain alive and free of disease, while patient 3 relapsed with extranodal disease 3 years after initial therapy. Conclusions: The natural history of In Situ-Mantle Cell Lymphoma varies with prolonged latency periods present in some patients. The genetic profile of the lymphoma may evolve during these latency periods portending a more aggressive clinical course at progression. Patients with newly diagnosed In-Situ Mantle Cell Lymphoma with no other evidence of active disease should be followed expectantly with therapy reserved for those patients whose disease progresses during followup.

6608 Background: Several prognostic factors can predict the course of chronic lymphocytic leukemia (CLL). Among them, the IGVH mutational status and the presence of cytogenetic abnormalities are the strongest predictors of outcome. Mutated IGVH and deletion 13q independently confer a survival advantage. CLL patients with mutated IGVH in combination with deletion 13q have a better prognosis when compared to their unmutated IGVH counterparts. However, there is limited data on the outcome of patients harboring favorable deletion 13q and the unfavorable unmutated IGVH. This study aimed at identifying patients with these two indicators in order to obtain important prognostic information. Methods: We used the Moffitt Cancer Center Total Cancer Care (TCC) database to find patients with a diagnosis of CLL between January 1993 and December 2009. Individual charts were reviewed for demographic data and CLL cytogenetics, including IGVH mutation status and presence of deletion 13q. We analyzed the impact of having deletion 13q in combination with an unmutated IGVH on the overall survival (OS) for this subset of CLL patients using Kaplan Meier curves with SPSS statistical software. Results: 546 patients were identified during the aforementioned time period with a diagnosis of CLL. Median age was 62.5 years. 144 (26.4%) of these patients had IGVH and cytogenetic analysis available. 53 patients had 13q deletion as their sole genetic abnormality. Patients with unmutated IGVH and positive for deletion 13q were 19/53 (35.8%). Patients with mutated IGVH and positive for deletion 13q were 34/53 (64.2%). Patients with mutated IGVH and positive for deletion 13q had an OS of 17 years. While patients with unmutated IGVH and positive deletion 13q had a lower median OS of 12 years (91.2% vs 78.9%, p=0.05). Hazard ratio for patients with IGVH mutated and positive deletion 13q was 0.4, p=0.05. Conclusions: Mutated IGVH appears to be associated with improved OS in patients with isolated 13q deletion when compared to patients with unmutated IGVH and isolated 13q deletion. Further research is needed to assess these mutations in relation to other cytogenetic abnormalities in CLL.

e21123 Background: B cell lymphoma, unclassifiable, with features intermediate between diffuse large B cell lymphoma (DLBCL) and Burkitt lymphoma (BL) or Burkitt like lymphoma is a high grade lymphoma that is associated with a high proliferation index and a complex karyotype mostly involving MYC and BCL-2 genes, so called “double hit” as well as BCL-6 or CYCLIND1 genes, so called “triple hit”. This high grade lymphoma shows an aggressive behavior for which the most appropriate therapeutic approach is yet to be established. Methods: This was a single center retrospective review of pts with a confirmed diagnosis of B cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL from 2006 to 2011. The definitive diagnosis in all cases was based on morphological and phenotypic features, and genetic abnormalities involving MYC, BCL-2, BCL-6, and or CYCLIND1. Clinicopathological data was extracted including age, gender, primary disease location, phenotypic subtype, genetic abnormalities by FISH, IPI scores, treatment regimens and survival data . Descriptive statistical analyses were utilized. Kaplan-Meier method was used to estimate OS and log rank test was used to compare the groups. All data were analyzed using SPSS version 20.0 statistical software. Results: 22 pts with "Double or Triple Hit" lymphomas were identified between 2006 and 2011. The age range at diagnosis was 33-87 years with median age of 66. 16 of 22 pts (73%) were ≥ 60 years old. Male to female ratio was 1.75 :1 (14:8). The median ECOG PS was 1. No pts had HIV. A majority of pts presented with extranodal disease 17 with only 5 pts presenting with nodal disease. The median survival of the entire cohort was 9 months with ranges 32 to 2 months. 16 of 22 pts (73%) are currently alive. In the cohort of pts that are currently alive, 10 was treated with RCHOP and 6 with RHyperCVAD. Pts who presented with CNS disease had a worse prognosis when compared to the entire cohort with a median overall survival of 6.5 months (p=0.016). Conclusions: RCHOP was the most utilized treatment regimen in the cohort of alive patients. CNS disease is associated with worse prognosis in patients with "Double or Triple Hit" lymphomas.

8084 Background: Relapsed/refractory non-Hodgkin lymphomas (NHL) have no standard of care. A variety of salvage chemotherapy options are available. We previously reported results of our phase II trial using gemcitabine, rituximab and oxaliplatin (GROC) in the salvage setting for relapsed/refractory NHL in which we observed an overall response rate of 58% with an incidence of grade 3-4 thrombocytopenia of 9% and neutropenic fever of 3.5%, but no grade 3-4 non-hematologic toxicities. Here we update progression free survival (PFS) and overall survival (OS) data. Methods: This phase II, single-arm, multicenter study evaluated safety and efficacy of GROC in patients with relapsed/refractory NHL. Patients were treated on a 14 day cycle. On day 1, patients with CD20+ NHL received rituximab (375 mg/m2). On day 2, patients received gemcitabine (1000 mg/m2) and oxaliplatin (100 mg/m2). Granulocyte colony stimulating factor was given. Stem cell transplant (SCT) was considered after a minimum of 6 cycles. Results: A total of 58 patients were enrolled from the H. Lee Moffitt and the Auxilio Mutuo Cancer Centers. Ages ranged from 24 to 88 years (median 72 years). The majority of patients had an ECOG performance status of 0-1 (89%). Lymphoid neoplasms included large B-cell (79%), follicular (7%), lymphoblastic (1.8%), Burkitt (1.8%), primary mediastinal large B-cell (3.5%), and peripheral T-cell lymphoma (7%). Eighty-one percent of patients had stage III-IV disease, median IPI was 3, 40% had B-symptoms, 43% had bulky disease and 74% had an elevated LDH. Anthracycline-based therapy had been used in 91% of patients and 66% had received rituximab. Median PFS was 134 days (95% CI 115-153) and median OS was 296 days (95% CI 164-428). No difference in response was observed based on age >60, IPI, LDH or albumin levels. Prior therapy with rituximab (p=0.02) and initial response to front-line therapy (p=0.04) appear to correlate with improved outcomes. Nine patients went on for SCT. Conclusions: GROC is a useful salvage regimen for relapsed/refractory NHL with minimal toxicities and good clinical efficacy. Several patients were able to be successfully mobilized, collected and transplanted post GROC therapy.

6568 Background: Patients with chronic lymphocytic leukemia (CLL) have a higher incidence of second malignancies than the general population with one study showing the risk at 2.2 times the general popualtion. The increased incidence is thought to be due to immunosupression which results in decreased cell surveillance and proliferation of malignant cells. Our study aims to present the rate of second malignancies by cancer type in patients with CLL at our institution. Methods: The Moffitt Cancer Center Total Cancer Care (TCC) database was used to identify patients who had a diagnosis of CLL between January 1993-December 2009. Individual charts were reviewed to confirm the diagnosis of CLL, collect demographic data, and to assess for the presence of a second malignancy under an IRB approved protocol. A second malignancy was defined as another malignancy or transformation of CLL reported in the medical record. Second malignancy data was placed in three categories; skin cancers, solid tumor malignancy, and hematologic malignancy. Results: 546 CLL patients were included in the study. Median age was 62.5 years. 84 (43%) were Stage 0 and 62 (32%) were Stage 1 RAI at diagnosis indicating earlier disease. 266 (49%) patients had a second or secondary malignancy. A total of 304 cancers were identified. 14% of patients had more than one malignancy. Melanoma was identified in 44 (16.5%) patients and non-melanoma skin cancer was identified in 54 (20%). Lung cancer was identified as the most frequent solid tumor malignancy with 36 (13.5%) cases, followed by prostate (35), breast (21), colorectal (15), and bladder (14). 10 patients had a Richter’s transformation of their CLL. 26 patients developed either myelodysplastic syndrome or acute myelogenous leukemia. Conclusions: Second malignancies are frequent in CLL patients. Immunosupression, increased UV light exposure, longer life expectancy in low risk CLL, and tertiary cancer center referral bias are likely reasons for these increased rates. Further research is needed to identify the precise mechanism which cause patients with CLL to have higher rates of second malignancies and to identify if there is an increased risk of a specific type of malignancy in patients with CLL.

e18509 Background: Standard therapy for aggressive Non-Hodgkin’s lymphoma (NHL) consists of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone), however the 5 year relapse rate is 20%. Patients with relapsed/refractory (RR) NHL are offered autologous stem cell transplantation (SCT) after salvage chemotherapy demonstrates chemosensitivity and reduces tumor burden. No standard salvage regimen for RR-NHL exists. Frequently used regimens include R-ICE (rituximab, ifosfamide, carboplatin, etoposide) and R-ESHAP (rituximab, etoposide, methylprednisolone, cytarabine, cisplatin). Which regimen provides the greatest efficacy with least toxicity remains unclear. Methods: Patients diagnosed with RR aggressive NHL who received R-ICE or R-ESHAP between 1/1/2000 and 9/30/2011 were identified. Patients may have received either regimen after failure of initial therapy. The primary objective was to determine the overall response rate (ORR) for each regimen. Secondary objectives included determination of overall survival (OS), and proportion of patients able to receive SCT. OS for each regimen was compared using Kaplan-Meier survival curves. Continuous data was compared using the student’s T-test. Results: The median age was 59 years, 27% were female and 90% were described as Caucasian. 78% were diagnosed with diffuse large B cell lymphoma (DLBCL), 13% with transformed follicular lymphoma, 9% with related aggressive NHL subtypes. 55% had a revised International Prognosis Score of 2. Conclusions: No standard of care exists for management of RR-NHL. No regimen has shown superior efficacy or long term outcomes over another. Our trial suggests similar ORR and OS between two commonly used regimens. Although toxicity profiles differ between these regimens, discontinuation rates due to toxicity were similar. The choice of salvage regimen may be determined by ease of administration, toxicity profile and patient/physician preference rather than improved efficacy between R-ICE and R-ESHAP. [Table: see text]

Abstract 4620 Introduction: Although bendamustine is approved for the treatment of chronic lymphocytic leukemia (CLL), the combination of bendamustine and rituximab (BR) is currently under active investigation in the relapsed/refractory setting as well as for front-line use. Emerging data now suggests BR is acceptable for first-line use and indeed is listed in the NCCN Compendia as a first-line option. Herein, we report the results of a single-center retrospective review of BR use in first-, second- and third-line and beyond and its effects on response rate. Methods: We retrospectively reviewed 21 consecutive patients with CLL that received BR at the Moffitt Cancer Center (MCC) between July 2008 and November 2010. Bendamustine was dosed at 70 mg/m2 IV on Days 1 and 2 every 3–4 weeks; rituximab was dosed at 375 mg/m2 IV once with each cycle along with anti-microbial prophylaxis. Data collected included, but was not limited to age, gender, cytogenetic profile, number of previous therapies, Rai stage at time of treatment and response (based on 1996 NCI-WG definition). The primary objective was to assess response rates. The major secondary objective was to assess the effect of cytogenetics on response rates. All analyses were performed using descriptive statistics. Results: Twenty-one patients received treatment with BR; 7 patients received BR as first-line therapy, 7 received BR as second line therapy and the remaining 7 received BR as third-line therapy or beyond. The median age at time of treatment was 66; 12 of 21 patients were male (57%); All Rai Stages were represented, Stage 0 (n=1), Stage 1 (n=4), Stage 2 (n= 3), Stage 3 (n=5), Stage 4 (n=6). 38% of patients were positive for Del11q, 33% for Del13q, 9.5% for Del17p, and 9.5% for mutated IgVH. In previously untreated patients, 6/7 had a documented complete remission (CR) (71.4%) or partial (PR) (14.3%) response; one patient progressed (PD) on therapy. In second-line therapy, all patients had a documented CR (28.6%) or PR (71.4%). In patients treated with BR as 3rd or 4th line therapy, 3 patients had a CR, 2 patients had stable disease (SD), and 2 had PD. Of the 8 patients with Del11q, 37.5% achieved a CR, 4 had PR and 1 had PD. Of the 7 patients with Del13q, 4 achieved CR and 3 had a PR. Both patients with Del17p had PD. Of the 2 patients with mutated IgVH, one patient achieved a PR while the other had PD. Conclusion: Based on these results, the combination of bendamustine and rituximab in patients with CLL is efficacious and well tolerated in patients with both newly diagnosed and relapsed/refractory disease. Disclosures: Off Label Use: Bendamustine and rituximab for CLL. Ho:Genentech: Honoraria; Cephalon: Consultancy. Cultrera:Genentech: Speakers Bureau. Sotomayor:Genentech: Membership on an entity’s Board of Directors or advisory committees. Pinilla-Ibarz:Genentech: Speakers Bureau; Cephalon: Speakers Bureau.

4241 Background: Acute lymphocytic leukemia (ALL) incidence is approximately 4000 cases per year in the USA. Several standard induction regimens are used upfront for the treatment of ALL. The HyperCVAD regimen is currently a widely used upfront treatment option for adult ALL patients based on pioneer work at MD Anderson Cancer Center (MDACC). Here we present our experience with the HyperCVAD regimen treating ALL at Moffitt Cancer Center (MCC), representing the largest cohort treated with this regimen outside MDACC. Methods: Patients who were diagnosed and treated at MCC with ALL were identified through the MCC Total Cancer Care database. Individual charts were reviewed. All patients treated with the HyperCVAD regimen frontline were included in this analysis. The HyperCVAD regimen was administered as originally described at MDACC. Philadelphia positive patients were treated with addition of tyrosine kinase inhibitors (TKI) (imatinib or dasatinib). Descriptive data are reported, t-test was used to compare continuous variables, chi square test for categorical variables, Kaplan Meier curves were used for overall survival (OS). Log rank test was used to compare survival times between groups. Cox regression analysis was used for multivariable analysis. All analyses were conducted using SPSS version 19.0 Results: Between 1/1/2002 and 6/30/2011, 100 ALL patients were treated with HyperCVAD at MCC. The median age was 45 years (range 18–83), 26 were above age of 60 years and 26 were below age of 30 years. Sixty three percent were male and 37% were female. Sixty five percent were white, 6% were African America, 7% were Hispanic and 22% were described as other. B-Cell ALL accounted for 83% of patients, while the other 17% had T-Cell origin. Of the 100 patients, 23% of patients were Philadelphia chromosome positive, while 72% were negative, and in 5% karyotype was unknown. Splenomegaly was present at diagnosis in 18% of patients, while 17% presented with lymphadenopathy. Twenty-three percent of patients presented with a WBC of 50,000 or greater. CNS disease was noted in 9% of patients at diagnosis. Seventy-six percent achieved a complete response (CR), while 12% had refractory disease. Response to frontline was not documented in 12% of patients. The median overall survival was 27 months (95% CI 15.6–38.3). In univariable analysis, no difference in outcome was observed based on gender, race, Philadelphia chromosome positivity, B or T-cell origin, presence of lymphadenopathy, splenomegaly, WBC >50,000 or CNS disease at presentation. Age was a significant prognostic factor. The median OS for patients 60 years old (95% CI 6.9–25.1) (p= 0.006) (figure-1) The median OS was higher in patients who achieved CR with frontline chemotherapy. OS was 34 months (95% CI 22.5–45.4) compared to 13 months in patients who did not achieve CR after frontline (95% CI 7.3–18.7) (p=< 0.005). Thirty-eight patients proceeded to allogeneic SCT. The median OS was 40 months in patients who proceeded to allogeneic SCT compared with 16 months in patients who did not (p=0.002). In Cox regression analysis, achieving CR with frontline induction, and allogeneic SCT were statistically significant independent variables for OS for adult patients with ALL. The odds ratio was 3.4 in patients achieving CR with frontline therapy, and 3.1 in patients who underwent allogeneic SCT. Conclusion: To our knowledge, this cohort represents the largest group of ALL patients treated outside MDACC with HyperCVAD based regimens, with similar overall results in the setting of tertiary centers. Achievement of CR after frontline therapy, and undergoing allogeneic SCT were statistically significant prognostic indicators. The outcome of elderly patients (age >60) was inferior. In the elderly population there were lower rates of CR and less number of patients proceeded to allogeneic SCT. The outcome in Philadelphia chromosome positive ALL has improved with the introduction of TKI’s and allogeneic SCT. Disclosures: No relevant conflicts of interest to declare.

4229 Background: Acute Lymphocytic Leukemia (ALL) is a heterogeneous and devastating disease in patients of all ages. However, there are prognostic indicators which are associated with worse outcomes including the presence of the Philadelphia (Ph) chromosome and age greater than 60. The percentage of ALL patients with Ph-positive disease increases with age. Relapse rates are much higher in Ph-positive ALL and five year survival rates are Methods: Using the MCC Total Cancer Care database, patients were identified who were diagnosed and treated with ALL at MCC. Patient charts were reviewed individually, and all patients who were age 60 and above were included in this analysis. Hyper-CVAD was administered as originally described at M.D. Anderson Cancer Center (Kantarjian 2000). The remaining patients were treated with regimens including the Larson protocol, CALGB study 8801 regimen, ECOG 2993 and vincristine/glucocorticoid combinations. Ph-positive patients were treated with the addition of a TKI. Descriptive data were reported, t-test was used to compare continuous variables while chi square test was used for categorical variables. Kaplan Meier curves were used for OS and relapse free survival (RFS). Long rank test was used to compare survival times between groups. Cox regression analysis was used for multivariable analysis. All analyses were conducted using SPSS version 19.0 and Microsoft Excel 2010. Results: Between 1/1/2004 and 6/30/2011, a total of 41 patients (age 60 or greater) were treated at MCC for ALL. Fifty-six percent of these patients were male, 44% were female. The majority of patients were Caucasian (81%), 2% were African American and 17% were classified as other. Thirty-nine were diagnosed with precursor B-cell ALL (excluding Burkitts Leukemia) and 2 had the T-cell subtype. Nine of the patients were found to have Ph-positive disease and 30 had Ph-negative disease. Two patients had an unknown Ph chromosome status. ECOG performance status was 0–1 in 78% of the treated patients. Other leukemia prognostic indicators were evaluated demonstrating five percent with known CNS involvement, 10% with lymphadenopathy and 15% of patients with splenomegaly at the time of diagnosis. There were no differences in observed outcomes based on these demographics. Sixty-three percent of patients were treated with HyperCVAD based chemotherapy frontline. All 9 patients with Ph-positive disease received a tyrosine kinase inhibitor. Seven of these patients were treated with imatinib and 2 received dasatinib. Our review demonstrated a median OS for all patients over the age of 60 treated with any therapy was 24 months (95% CI 15–33). The OS for patients treated with HyperCVAD was 23 months (95% CI 14.9–31.1) as compared to 24 (95% CI 14.8–33.2) in those treated with other regimens (p=0.299)(fig 1). OS was 24 months (95% CI 14.8–33.2) in Ph-positive patients who were treated with a TKI as compared to 23 months (95% CI 12.7–33.3) in Ph-negative patients who were treated with standard chemotherapy (p=0.95). Two patients were able to proceed to allogeneic hematopoetic stem cell transplant. Conclusion: In our experience prognosis remains poor in older adults with ALL. There was no statistical significant difference observed in median OS based on the type of chemotherapy regimen used in this population. Outcomes do appear improved in older adults with Ph-positive ALL with the use of TKIs. Disclosures: No relevant conflicts of interest to declare.

Abstract 4973 Background/Rationale: Rituximab is an anti-CD-20 monoclonal antibody used in the management of lymphoproliferative disorders. Rituximab is indicated in maintenance therapy for follicular cell lymphoma and can be administered once every 2 months, once every 3 months, or weekly for 4 weeks every 6 months. The use of maintenance rituximab has improved progression free survival and overall survival in low grade follicular lymphomas. Although rapid rituximab infusions have been studied extensively, there is little data on the use of rapid infusions during maintenance therapy for low grade lymphomas. Herein we report our experience with rapid infusion rituximab in patients receiving maintenance therapy. Methods: All patients who received rapid infusion rituximab as maintenance therapy for low grade lymphoma between December 2007 and June 2011 were included. Patients were considered eligible for rapid infusions if they tolerated previous rituximab infusions and presented with a peripheral lymphocyte count of less than 4.8 k/μl. Rapid rituximab infusions were administered over 90 minutes (150 mL/hr for 30 minutes and then increased to 275 mL/hr until completion). Patients were monitored for signs and symptoms of reactions. In case of an infusion reaction supportive care medications were readily available. Demographic, laboratory and clinical data were collected. Adverse events were assessed through vital signs, symptoms of infusion related reaction and supportive care measures administered and graded according to the Common Terminology Criteria for Adverse Events Version 4. The primary and secondary objectives of this retrospective study were to evaluate the incidence of grade 3/4 and all grade infusion reactions with rapid rituximab infusions during maintenance therapy, respectively. Maintenance schedules were also compared with regards to incidence of infusion reactions. Results: A total of 105 patients received 629 rapid rituximab infusions. Patient demographics, laboratory, and clinical data are summarized in Table 1. All patients were eligible for rapid infusion rituximab according to institutional criteria. Two grade 2 infusion reactions and 4 grade 3 reactions were reported (1 patient experienced a grade 2 and 3 reaction); however none of these patients required hospitalization. All 5 patients received pharmacological and/or supportive care to relieve the symptoms associated with the reaction. Of these 5 patients, 3 patients went on to receive rapid infusions of rituximab; 2 patients were switched to standard infusion per physician request. The sample size was too small to determine if a correlation existed between infusion related reactions and the schedule of maintenance rituximab. Conclusion: The rapid infusion of rituximab in patients receiving maintenance therapy is well tolerated with minimal incidence of infusion-related reactions. Although the sample size was insufficient to assess differences in adverse effects according to the maintenance schedule, the low overall incidence of adverse effects suggests that rapid rituximab infusions are well tolerated regardless of maintenance schedule. Our study concludes rapid infusion rituximab is a safe and feasible option for maintenance therapy. Disclosures: Ho: Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees. Off Label Use: Maintenance Rituximab Therapy in Non-Hodgkin's Lymphoma. Cultrera:Genentech: Speakers Bureau. Sotomayor:Genentech: Membership on an entity's Board of Directors or advisory committees. Wetzstein:Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees.

4248 Background: According to US SEER data, 10.3% of patients diagnosed with Acute Lymphoblastic Leukemia (ALL) during 2004–2008 were 20–34 years old. The majority of patients, 60.3%, diagnosed were under 20, and the remainder were over 35 years of age. Many retrospective trials have looked at treatment of adolescents and young adults (AYA) with ALL, and overall survival (OS) rates after treatment with pediatric regimens versus adult protocols. European studies done in the early 2000’s found improvement in OS and progression free survival (PFS) in this population when treated with pediatric regimens. Differences in pediatric versus adult regimens include increased doses of non-myelosuppressive drugs such as glucocorticoids, Vincristine and Aspariginase, more frequent CNS prophylaxis, and longer maintenance therapy. These differences, unfortunately, often cause harsh toxicities, not well tolerated by adults. Here we present our experience at Moffitt Cancer Center (MCC), in treating AYA’s (age Methods: We used the MCC Total Cancer Care database to identify patients with ALL who underwent intensive therapy. Patient medical records were reviewed, and patients between 18–30 years of age were included in this analysis. Hyper-CVAD was the most common adult regimen, while CALGB 10403 and ECOG 2993 were the most common pediatric regimens. Descriptive data were reported, t-test was used to compare continuous variables while chi square test was used for categorical variables. Kaplan Meier curves were used for OS and PFS. Log rank test was used to compare survival times between groups. Cox regression was used for multivariable analysis. All analyses were conducted using SPSS version 19.0. Results: Between 1/1/2004 and 6/30/2011, 42 AYA ALL patients were treated at MCC. Males accounted for 74%, while 26% were female. Hyper-CVAD was used as frontline chemotherapy in 64% of patients, while 31% received a pediatric regimen. Of the 42 patients, 64% were white, 5% African American, 12% Hispanic and 19% were classified as other. Pre-B ALL made up 69% of patients, while 31% had T-cell origin. Cytogenetics category at diagnosis was adverse in 29% of patients, intermediate in 55% and favorable in 12% of the population, while 5% were unknown. Philadelphia chromosome was positive in 17%. At diagnosis 38% had lymphadenopathy, 33% had splenomegaly and 12% had CNS disease. Overall, 45% underwent allogeneic stem cell transplant (SCT) in CR1, while 55% did not. Overall, 85% of patients achieved CR, including 81% receiving Hyper-CVAD and 92% with pediatric regimens. Median PFS was 30.8 months (95% CI 21.9–39.7) for the entire AYA population, 31.2 months (95% CI 13.2–49.3) in the Hyper-CVAD group and 21.3 months (95% CI 0.0–49.6) in the pediatric regimen group. (P=0.124) (Figure 1) Median OS in the entire AYA population was 31 months (95% CI 15.3–46.7). OS with Hyper-CVAD was 31 months (95% CI 19.7–42.2) versus 30 months (95% CI 3.1–56.9) in the pediatric group (P=0.984). (Figure 2) Median PFS was 44.8 months in patients who had an allogeneic SCT versus 23 months in those who did not (P=0.009). Further, there was a trend toward worse outcomes in patients with adverse cytogenetics. Median OS in patients who had an allogeneic SCT was 39 months (95% CI 16.8–61.2) versus 31 months (95% CI 15.2–46.8) in those who did not. (P=0.424). In univariable analysis, no difference in outcome was found based on race, gender, T or B cell origin, lymphadenopathy or splenomegaly. Using Cox regression analysis, Philadelphia chromosome positivity (P= 0.009), elevated WBC (P=0.008) and CNS disease at diagnosis (P=0.029) were statistically significant independent variables for OS for all patients. Conclusion: Optimal treatment of AYA with ALL remains unclear. The role of pediatric versus adult regimens remains controversial, and further prospective investigation is necessary. In our experience, outcomes in AYA appear similar between Hyper-CVAD and pediatric regimens. Improvement in PFS is noted if patients are able to undergo allogeneic SCT. In addition, Philadelphia chromosome positivity, elevated WBC at diagnosis and CNS disease appear to be independent variables that negatively affect prognosis in these young patients, for whom more novel therapies are needed. Disclosures: No relevant conflicts of interest to declare.

Abstract 2879 Background: Non-Hodgkin's Lymphomas (NHL) are heterogeneous group hematologic malignancies. Although diffuse large B-cell lymphoma can be treated effectively with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) there is a relatively high relapse rate requiring alternative chemotherapy regimen. The optimal salvage regimen is not known. Intensive multi-agent chemotherapy in combination with rituximab yield often responses up to 50 to 60% in relapsed/refractory NHL. In this study we sought to evaluate the efficacy of gemcitabine, rituximab and oxaliplatin in combination as a useful salvage regimen in patients with relapsed or refractory NHL. Methods: This trial was designed as a prospective, open and uncontrolled phase II study. From May 2004 to December 2009, 59 patients with relapsed or refractory NHL from Auxilio Mutuo Cancer Center, (San Juan, PR) and H. Lee Moffitt Cancer Center & Research Institute (Tampa, FL) was enrolled in this study examining the efficacy of GROC on a 2 week schedule. On day 1, patients with CD20 positive NHL received rituximab at 375mg/m2 followed by gemcitabine (1000 mg/m2 to 1750mg/m2) and oxaliplatin (100mg/m2) on day 2 along with growth factor support on a day 14 of each cycle. Patients with CD20 negative malignancies (i.e. peripheral T-cell lymphoma) received only day 2 of therapy along with growth factor support. Primary endpoint was response rate. Secondary endpoints were toxicity evaluation, progression free and overall survival. Patients were followed for toxicity, response, progression free survival (PFS) and overall survival (OS). Patients were allowed to come off study for hematopoietic stem cell transplant (HSCT) consolidation after a minimum of six cycles of therapy. Results: 57 evaluable patients represented typical heterogeneity noted in NHL in North America. Most of the patients were male 63% (36 patients) with ages ranging from 24 to 88 (median 62) years old with 31% patients age 60 or greater. Histologies included large B-cell (79%), follicular (7%), lymphoblastic (1.8%), Burkitt's (1.8%), primary mediastinal large B-cell (3.5%), and peripheral T-cell lymphoma (7%). Twenty-one patients (37%) demonstrated extranodal disease at one or more sites at presentation indicating a more aggressive lymphoma. Median IPI (International Prognostic Index) score was 3 though most patients presented with advanced stage (III or IV). Most patients had received first line therapy utilizing an anthracycline based regimen such as CHOP, 89% (51 patients) and 65% (37 patients) percent having received prior rituximab therapy. Other utilized regimens included CHOP modifications, methotrexate plus cytarabine, bleomycin plus ESHAP (etoposide, solumedrol, cytarabine and cisplatin), and CHOP plus melatonin in at most one patient per therapy. The majority of patients after first line induction therapy were complete responders. In intent-to-treat analysis of responses a majority of the patients experienced either a CR (including unconfirmed, 14 of 57) or PR (19 of 57) demonstrating an overall response rate approaching 58%. Stable disease was observed in 10.5% (6) patients. Disease progression occurred in 29.8% (17) patients. Progression free survival ranged from zero to 67 with a median of 4 months. Overall survival measured from 1 to 38 months with a median of 7 months, follow-up of this population continues. At last follow-up 37% of (21 of 57) were alive. Toxicity profile of this regimen was similar to other salvage therapies used in this patient population with an increased incidence of grade 3/4 thrombocytopenia (9%) and neutropenic infections (3.5%). Several patients, 8, were able to proceed with adequate hematopoietic stem cell collection post GROC therapy for autologous HSCT. No grade 3 and 4 non-hematologic toxicities were observed. Conclusions: Our results demonstrate that in patients with advanced stage, relapsed or refractory non-Hodgkin's lymphomas, GROC is a useful salvage regimen with acceptable toxicities and comparable efficacy to similar salvage regimens. GROC can also be used as a bridge to auto-HSCT. Disclosures: Off Label Use: Bendamustine in the treatment of multiple myeloma. Sokol:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Cabanillas:Bayer Pharmaceuticals: Research Funding; Genentech: Research Funding.

Abstract 5082 Background: Prognosis for survival in mantle cell lymphoma (MCL) has recently been characterized using the MIPI algorithm. Using a retrospectively generated dataset of 150 patients with MCL seen at the H Lee Moffitt Cancer Center we sought to validate this approach in a more heterogeneous population. Methods: Patients were identified by physician survey, and through the use of our pathology and Total Cancer Care databases. Retrospective analysis was conducted with approval of our Institutional Review Board. In total 150 patients with MCL were identified, among whom MIPI data was available for 85 patients with a median followup of 36.8 months. Survival (expressed in months) was verified using our institutional records and the Social Security Death Index. Exploratory analysis of progression (n=79) and survival from the time of relapse (n=43) as stratified by MIPI were also conducted among evaluable patients. Data were compared using Kaplan-Meier survival analyses. Results: Median age was 65y (range 31–87), 73% male, 3% ECOG >1, 88% stage III/IV disease, 36% with extranodal involvement, and 38% with splenomegaly. Evaluation of the entire cohort shows median OS 57 (95% CI: 48, 70.9), median PFS 21.8 (95% CI: 14.2, 25.6), and median survival after relapse 27.6 (95% CI 25.4, 30.8). No benefit in OS was observed among patients receiving Cytarabine (HR 1.04, p=0.91) and/or Rituximab (HR 1.31, p=0.61) with initial chemotherapy. Relationship between PFS and survival after relapse demonstrated rho=0.51 (p Among 85 evaluable patients 36% had elevated LDH, while 36% were MIPI-Low, 38% MIPI-Int, and 28% MIPI-High. Stratification by MIPI shows median OS of 30.4 (12.4, 42) for MIPI-High, 64.8 (53,-) for MIPI-Int, and has not been reached by MIPI-Low, with little separation between MIPI-Low and MIPI-Int groups before 60 months. PFS was 6.3 (3.7,15) for MIPI-High, 25.6 (16.5,31) for MIPI Int, and 26.5 (14,40.3) for MIPI-Low, with little separation between MIPI-Low and MIPI-Int groups before 30 months. Survival after relapse was 12.4 (9.1,25.4) for MIPI-High, 34.2 (27.6,-) for MIPI-Int, and was not reached for MIPI-Low, again with little separation between MIPI-Low and MIPI-Int groups before 30 months. Conclusions: In our experience, the MIPI remains an effective tool for stratification of OS in MCL, however, extended followup is needed to realize such differences among those with MIPI-Low and MIPI-Int disease. The MIPI was similarly effective in predicting a poor PFS and survival from relapse among those with high risk disease, though was of less utility among MIPI-Low and MIPI-Int patients. Disclosures: No relevant conflicts of interest to declare.

Abstract 3122 Adult T-cell leukemia/lymphoma (ATL) is an aggressive, fatal malignancy of CD4+ T cells that is etiologically associated with infection by human T-cell leukemia virus-type. ATL has been classified into four main subtypes, indolent smoldering, chronic forms, acute and lymphomatous forms. Most individuals in the chronic stage of ATL eventually undergo progression to a highly aggressive acute stage. Compelling evidence supports a pivotal role for altered tumor suppressor genes involved in leukemogenesis and lymphomagenesis of ATL as well as progression of the disease from the chronic/smoldering to the acute/lymphomatous type. Further investigations are needed as to how the alteration of cell cycle regulatory genes are involved in the aberrant growth of HTLV-infected T cells. The emerging role of microRNAs in tumor development and viral infection has prompted investigations on the role of microRNA in ATL pathogenesis and progression. We therefore performed microRNA microarrays on 16 lymphomatous tissues of ATL patients and normal CD4 lymphocytes of 5 healthy donors. After normalization, we identified a set of aberrantly expressed miRNAs in ATL lymphoma samples when compared with control CD4 lymphocytes including 49 upregulated microRNAs and 89 downregulated microRNAs. MiR-150, miR-24, miR-221, miR-222, miR-142-5p, miR-92b, miR-93, miR-181a, miR-103, miR-107 stands out as highly elevated miRNAs in ATL samples while miR-30b, miR-34a, miR-20b, miR-196b, miR-361-5p, miR-520b/e are found downregulated in ATLL samples. Using gain-and-loss experimentations, we demonstrated miR-181a overexpression decreases, whereas miR-181a inhibition increases a proapoptotic protein, Bim, levels by directly targeting Bim. Furthermore computational analysis, and previous studies revealed that that miR-214, miR-22, miR-93 increased AKT activity by repressing PTEN expression, and miR-221/222 and miR-93 promoted cell proliferation through inhibition of CDKN1B (p27). Overall, this study demonstrated a distinct set of miRNAs that are known to be critical in cellular transformation, representing a novel molecular mechanism and potential therapeutic targets in ATL lymphoma. Disclosures: No relevant conflicts of interest to declare.

Abstract 4370 Introduction Bendamustine is indicated for the treatment of CLL and rituximab-refractory indolent NHL. Clinical trials have reported 25% incidence of infusion related reactions (IRR) in patients receiving bendamustine. While these reactions are well documented, there is no consensus on the optimal premedication regimen for the prevention of these adverse effects. The Moffitt Cancer Center (MCC) utilizes a regimen of ondansetron 16 mg PO and dexamethasone 10 mg IVP prior to each bendamustine infusion. Herein, we report our experience with our current premedication regimen with regards to the IRR as well as the incidence of febrile neutropenia (FN). Methods We retrospectively analyzed 79 consecutive patients receiving bendamustine infusions at MCC from June 2008 to June 2010 to determine the incidence of IRR and FN. Data collected include baseline laboratory values, diagnosis, dosing, number of bendamustine infusions, concurrent rituximab use, growth factor utilization, as well as safety data including the rate of adverse reactions, interventions, and hospitalization. The primary objective was to determine the incidence of IRR. Secondary objectives include incidence of febrile neutropenia and hospital admission rate. All analyses were performed using SPSS 17.0. Descriptive statistics were used to analyze data. Results 79 consecutive patients received a total of 513 bendamustine infusions at MCC. Median age was 68 years; M:F (52:27). The most common primary malignancies were indolent non-Hodgkin's lymphoma (NHL), 56%; chronic lymphocytic leukemia (CLL), 38%; and multiple myeloma (MM) 6.3%. Patients had received a median of 2 regimens prior to initiation of bendamustine. Bendamustine was utilized as first line treatment in 25% of patients, second line in 17.7%, third line in 25%, and fourth line or greater in 32.3% of patients. Bendamustine infusions were well-tolerated. Infusion-related reactions (IRR) occurred at a rate of 3.35% (17/513) with all reactions attributed to rituximab. Most commonly reported reactions reported were rigors (2%), chills (1%), and fever ( Conclusion Based on our experience with bendamustine, ondansetron and dexamethasone provide safe and effective prevention of infusion related reactions associated with bendamustine. Notably, all infusion reactions were attributed to rituximab infusions and no patients experienced an infusion related reaction when receiving bendamustine alone. This compares favorably to the initial reported infusion-related reactions with bendamustine alone (25%). In avoiding the use of other premedications, the likelihood of additional complications or adverse affects can be minimized. The overall incidence of FN was comparable to previously published studies. As may be expected, heavily pretreated patients had a higher incidence of FN (6% vs. 16%) than those who had received 1 or no previous treatments and may warrant growth factor support. Disclosures: Tombleson: Cephalon: Research Funding. Off Label Use: Bendamustine used for the treatment of myeloma. Ho:Cephalon: Consultancy, Research Funding. Pinilla-Ibarz:Cephalon: Speakers Bureau. Wetzstein:Cephalon: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Introduction: Epigenetic changes have been implicated in the pathogenesis of several human hematologic malignancies, including non-Hodgkin’s lymphomas (NHL). Vorinostat, a novel pan-histone deacetylase inhibitor (HDACi), has shown significant clinical activity in cutaneous T-cell lymphoma. This class of agents enhances transcription of target genes through histone hyperacetylation and through interactions with signal transduction mediators and transcription factors. Bortezomib is a reversible inhibitor of the chymotrypsin-like activity of the human 20s proteasome with established clinical activity in mantle cell lymphoma. The combination of vorinostat and bortezomib has exhibited synergism in several hematologic malignancy models. We sought to further explore the effects of these two agents in T-cell NHL cell lines and explore levels of apoptosis in response to combination treatment with vorinostat and bortezomib. Methods: A panel of T-cell NHL cell lines (SR, SUDHL1, SUPM2, SUPT1, L82, and HH), representing several different subtypes, were evaluated to assess the activity of vorinostat and bortezomib. Cells were plated at a concentration of 2 × 105 cells/mL and cultures were treated with varying concentrations of each agent (0.5 μM to 10 μM) and assessed after 24 hours for levels of apoptosis. Apoptosis and viability were analyzed through propidium iodide flow cytometry. Levels of apoptosis were considered significant at 30% cells in sub G0 phase. Further studies were undertaken to assess possible mechanisms of action contributing to this apoptosis. TRAIL, DR4, and DR5 concentrations were measured in these lines through ELISA and cell surface flow cytometry. Results: Heterogeneity was observed throughout the various T-cell NHL lines in response to vorinostat and bortezomib as single agents. After treatment with 1 μM of vorinostat and 5 nM of bortezomib, L82 cells (ALK negative anaplastic large cell lymphoma) exhibited approximately 40% and 60% apoptosis respectively (see figure 1). These concentrations of both vorinostat and bortezomib are consistent with clinically relevant maximum tolerated dose equivalents for each agent. IC50s were obtained for all cell lines tested within therapeutic ranges. Combination therapy resulted in additive levels of apoptosis in all cell lines, with a subset resulting with synergistic apoptotic levels as indicated by combination index values < 1 using the median effect method of Chou and Talalay (see figure 2). Apoptosis in L82 cells treated by a combination of suboptimal doses of each agent (vorinostat 0.5 μM and bortezomib 0.5 nM) was substantially higher at 35%. Similar results were noted for the SUPT1 and HH cell lines at levels of vorinostat 1 μM/bortezomib 1 nM and vorinostat 0.5 μM and bortezomib 1 nM respectively. In cells treated with vorinostat and bortezomib as single agents and in combination, upregulation in the components of the TRAIL dependent apoptotic system was noted. Transcriptional increases of DR5 and TRAIL mRNA was demonstrated in a dose dependent manner after single agent treatment of vorinostat and bortezomib in L82, SUDHL1, and HH cell lines. Further, flow cytometry and ELISA measurements demonstrated an increase in protein levels of DR5 and TRAIL in a dose dependent manner with both vorinostat and bortezomib. Conclusions: There is evidence that T-cell NHL cells are sensitive to both vorinostat and bortezomib as single agents and that there is synergy with combination therapy. TRAIL/DR5 expression may be altered by treatment with these agents and cause cell death through the extrinsic apoptotic pathway. These findings warrant further exploration of this combination in the clinical setting. FIGURE 1: Vorinostat and bortezomib activity in T-cell NHL T-cell NHL cell lines after treatment with vorinostat (A) and bortezomib (B) as single agents at varying concentrations. FIGURE 1:. Vorinostat and bortezomib activity in T-cell NHL . / T-cell NHL cell lines after treatment with vorinostat (A) and bortezomib (B) as single agents at varying concentrations. FIGURE 2: Synergism of vorinostat and bortezomib in T-cell NHL L82 cells after treatment with vorinostat and bortezomib in combination. FIGURE 2:. Synergism of vorinostat and bortezomib in T-cell NHL . / L82 cells after treatment with vorinostat and bortezomib in combination.

Abstract 1660 Recently, we have found that HDAC6 is overexpressed in MCL cell lines and in primary human MCL cells. Knocking-down HDAC6 in MCL cells with a shRNA lentiviral system resulted in cell cycle arrest and apoptosis induction. Interestingly, MCL cells lacking HDAC6 displayed a significantly decreased STAT3 phosphorylation and abrogation of IL-10 gene transcriptional activity. ACY1215 is a novel, selective, orally bioavailable HDAC6 inhibitor. Treatment of MCL cell lines with this agent resulted in decreased cell viability and proliferation. In addition, ACY1215 inhibits IL-10 production in a dose dependent manner. Bruton tyrosine kinase (BTK) is a member of Tec family of kinases with a very distinct role in B-cell antigen receptor (BCR) signaling. The selective BTK-inhibitor PCI-32765 has shown promising pre-clinical and clinical activity in MCL. In addition to their direct anti-lymphoma effects, disruption of BTK also induces positive immunological changes such as inhibition of the immunosuppressive STAT3/IL-10 signaling pathway1. The above observations led us to determine whether the direct antitumor effects and the immunological properties of ACY1215 and PCI-32765 could be potentiated when these agents are used in combination. First, the viability of MCL cells was decreased when they were treated in vitro with either PCI-32765 or ACY1215. However, combination of these two agents resulted in a 3-fold increase in apoptosis induction, pointing to a synergistic effect of BTK and HDAC6 inhibition in MCL. The additional findings that this approach can increase the immunogenicity of MCL cells and anti-MCL immune responses has provided the proper framework for combining the selective HDAC6 inhibitor ACY1215 with BTK inhibition as a novel therapeutic strategy in MCL. Disclosures: Chen-Kiang: Bristol Myers Squibb: Consultancy; Pfizer: Research Funding. Jones:Acetylon Pharmaceuticals, Inc: Employment.