Goy, Andre Henri

Abstract Introduction Patients with mantle cell lymphoma (MCL) typically respond to initial therapy and almost inevitably relapse with frequent chemoresistance over time and poor outcome. Multiple phase II studies have established the efficacy and safety of lenalidomide, an immunomodulatory agent with tumoricidal and antiproliferative properties, in relapsed/refractory MCL. The prospective phase II multicenter MCL-001 “EMERGE” study led to FDA approval of lenalidomide for patients with relapsed/refractory MCL after 2 prior treatments, that included bortezomib. The activity of lenalidomide was seen regardless of MIPI, number of prior therapies, prior high dose therapy, bulky disease or high tumor burden. One of the most established prognostic factors in MCL is the proliferation index Ki67 (MIB1), now confirmed both in standard and dose-intensive high-dose therapy strategies. We present here longer follow-up of efficacy and safety from the MCL-001 study in patients relapsed/refractory to bortezomib and the potential relationship between Ki-67 and efficacy outcomes. Methods Patients with heavily pretreated MCL, that included prior bortezomib, received lenalidomide 25 mg/day PO, days 1-21 in 28-day cycles until disease progression or intolerability. Primary study endpoints were overall response rate (ORR) and duration of response (DOR); secondary endpoints included complete response (CR), time to response (TTR), progression-free survival (PFS), overall survival (OS), and safety. Response rates and time-to-event data were analyzed by independent central reviewers per modified IWG criteria and Kaplan-Meier estimates respectively (data cut-off March 20, 2013). Ki-67 was examined as an exploratory endpoint by immunohistochemistry for 81/134 patients (60%) either performed on biopsy samples for 24 patients, or based on the Ki-67 scores reported in local pathology reports for 57 patients. Results Median age for the enrolled intent-to-treat patient population (N=134) was 67 years (range, 43-83; 63% ≥65 years). The median number of previous therapies was 4 (range, 2-10; 78% received ≥3), 93% stage III/IV, and 72% were <6 months from last prior treatment. At a median follow-up of 13.2 months, the ORR was 28% (CR/CRu 8%), with a median DOR of 16.6 months (95% CI, 9.2-26.7; median not reached in patients with CR/CRu) by central review. Median TTR was 2.3 months (95% CI, 1.7-13.1), with a median time to CR/CRu of 4.1 months (95% CI, 1.9-13.2). Median PFS was 4.0 months (95% CI, 3.6-6.9), and median OS was 20.9 months (95% CI, 13.7-24.4). The average dose intensity of lenalidomide was 20 mg/day, for a median duration of 94.5 days (range, 1-1,256). Dose reductions or interruptions due to adverse events (AEs) occurred in 40% and 58% of patients, respectively. Neutropenia (44%), thrombocytopenia (28%), and anemia (11%) were the most common treatment-related grade 3/4 AEs. Ki-67 results were available in 81/134 patients, and efficacy data were categorized using 30% and 50% cut-off thresholds for Ki-67 expression (Table 1). Although patient numbers were limited, the ORR was similar in both lower and higher Ki-67 group, but those with lower Ki-67 levels demonstrated better CR rates, DOR and survival outcomes compared with patients with elevated Ki-67. Conclusions Single-agent lenalidomide in heavily pretreated patients with relapsed/refractory MCL post-bortezomib showed durable long-term efficacy with a consistent safety profile. Consistent with what is reported in the literature, high Ki-67 is associated with poor outcome in our cohort with shorter OS. Though based on retrospective evaluation and subsets of patients, the ORR to lenalidomide was similar in both low and high Ki-67 groups, suggesting lenalidomide can be active in patients expressing high levels of Ki67. Prospective studies are needed to confirm these findings. Disclosures: Goy: Celgene: Consultancy, Research Funding, Speakers Bureau. Off Label Use: This is a phase 2 clinical study of safety and efficacy for lenalidomide in patients with MCL. Williams:Celgene: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Research Funding. Drach:Celgene: Honoraria. Ramchandren:Celgene: Research Funding. Zhang:Celgene: Employment. Cicero:Celgene: Employment. Fu:Celgene: Employment. Heise:Celgene: Employment, Equity Ownership. Witzig:Celgene: Research Funding.

Abstract Abstract 2477 Background: Aurora A kinase (AAK) is a key mitotic regulator, inhibition of which results in mitotic spindle defects, mitotic delay, and apoptosis. AAK is amplified or overexpressed in a number of heme-lymphatic malignancies. This phase 1, multicenter study (NCT00697346) is the first to assess safety, tolerability, and pharmacokinetics (PK) of the investigational AAK inhibitor alisertib (MLN8237) in patients with advanced hematologic malignancies. Methods: Patients aged ≥18 years with relapsed/refractory hematologic malignancy, confirmed radiographically or clinically evaluable disease, and ECOG performance status 0–2, were eligible for inclusion. Patients with prior allogeneic transplant were excluded; there was no restriction on the number of prior therapies. Patients received escalating doses (standard 3+3 design) of alisertib as either a powder-in-capsule (PIC) or enteric coated tablet (ECT) formulation. Alisertib PIC was administered as a twice-daily (BID) loading dose on Day 1, then once daily (QD) on Days 2–14 or 2–21, followed by 14 or 7 days' rest, respectively, in 28-day cycles. Alisertib ECT administration followed the same scheme in the first dose group, and subsequent groups received divided (BID) doses for 7 days plus 14 days' rest in 21-day cycles. Endpoints included maximum tolerated dose (MTD), dose-limiting toxicity (DLT), safety, PK, and response. Results: 55 patients were included (PIC n=28, ECT n=27); median age was 61 years (range 27–82), 42% had prior ASCT, and 78% had received ≥3 prior therapies. 60% of patients had non-Hodgkin's lymphoma, 35% multiple myeloma, and 5% chronic lymphocytic leukemia/small lymphocytic lymphoma. Patients received a median of 2 cycles (range 1–14); 8 patients are ongoing. The MTD on the alisertib PIC 14-day + 14 days' rest schedule was 45 mg QD, established following occurrence of DLTs in four patients at higher dose levels: Gr 4 thrombocytopenia, Gr 4 neutropenia (65 mg QD); Gr 3 febrile neutropenia, Gr 4 thrombocytopenia (90 mg QD). In patients receiving alisertib ECT, the MTD was determined as 50 mg BID on a 7-day + 14 days' rest schedule; four DLTs were observed in three patients: at 40 mg QD for 14 days, one patient had Gr 4 febrile neutropenia, and one patient had Gr 4 bullous dermatitis and Gr 4 neutropenia; at 50 mg BID for 7 days, one of nine patients had Gr 4 neutropenia. The most common drug-related adverse events (AEs) were neutropenia (PIC 46%, ECT 63%), thrombocytopenia (39%, 41%), and diarrhea (29%, 41%); most common Gr ≥3 drug-related AEs were neutropenia (PIC 36%, ECT 52%), thrombocytopenia (29%, 26%), and anemia (14%, 26%). 24 patients (PIC n=12, ECT n=12) had serious AEs; the most common was febrile neutropenia (PIC n=1, ECT n=4). Tolerability appeared generally similar between the PIC and ECT formulations. Six patients (PIC n=3, ECT n=3) died during the study (PIC: renal failure, airway obstruction, progressive large cell lymphoma; ECT: progressive myeloma [n=2], hypercalcemia); no deaths were considered to be related to alisertib. Alisertib absorption was rapid with an overall median Tmax of 2 hours. The overall mean terminal half-life following multiple dosing was 19 hours. The mean peak/trough (P/T) ratio was 5 following QD dosing as PIC. The mean accumulation ratio and P/T ratio were 2.5 and 2.1, respectively, following BID dosing as ECT. At data cut-off (29 March, 2011), 42 patients were evaluable for response. Antitumor activity was observed in five patients (PIC n=3, ECT n=2) who had partial responses; 11 patients had a best response of stable disease (PIC n=6, ECT n=5) and 26 had progressive disease (PIC n=14, ECT n=12). Seven patients received ≥5 cycles of therapy, including one patient (PIC group; post-transplant grade 3B follicular lymphoma) with resolution of B symptoms who received alisertib for >1 year. Conclusions: The MTDs of the PIC and ECT formulations of alisertib are 45 mg QD for 14 days (+14 days' rest) and 50 mg BID for 7 days (+ 14 days' rest), respectively, in patients with advanced, non-leukemic hematologic malignancies. AEs were generally manageable and were consistent with inhibition of AAK in highly proliferative tissues (gastrointestinal and hematologic AEs). Current data support further investigation and expansion at the MTDs is ongoing. Data from PK, safety, and tolerability collectively support the progression of ECT formulation at 50 mg BID for 7 days in a 21-day cycle into phase 2 development. Disclosures: Off Label Use: Investigational agent in clinical development for the treatment of advanced hematologic malignancies and solid tumors. Goy:Millennium Pharmaceuticals, Inc.: 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, Speakers Bureau; GSK: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genentech: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Reeder:Millennium Pharmaceuticals, Inc.: Institutional research funding; Novartis: Institutional research funding; Celgene: Institutional research funding. Zhou:Millennium Pharmaceuticals, Inc.: Employment. Danaee:Millennium Pharmaceuticals, Inc.: Employment. Xiao:Millennium Pharmaceuticals, Inc.: Employment. Benaim:Millennium Pharmaceuticals, Inc.: Employment, Equity Ownership. Shea:Millennium Pharmaceuticals, Inc.: Consultancy, Research Funding.

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

Abstract Introduction Ibrutinib has become a new standard of care in patients with previously treated CLL/SLL based on the phase 3 RESONATE study (Byrd, et al. NEJM 2014) and other trials evaluating ibrutinib mainly as a single agent in CLL. The first randomized, double-blind, placebo-controlled phase 3 study (HELIOS) investigating ibrutinib in combination with bendamustine and rituximab (BR) was recently reported (Chanan-Khan, et al. ASCO 2015), with ibrutinib significantly extending progression-free survival and reducing the risk of progression/death by 80%. The study design provides an opportunity to examine the overall safety and management of adverse events (AEs) with ibrutinib and placebo in a blinded manner that previously has not been possible. Here we examine the safety and management of AEs with ibrutinib + BR vs placebo + BR in HELIOS. Methods Patients with active CLL/SLL following ≥ 1 prior line of systemic therapy were randomized 1:1 to receive BR (≤ 6 cycles) with either ibrutinib 420 mg daily or placebo (n = 289 in each group). Safety was a secondary end point. Results Median exposure to ibrutinib and placebo was 14.7 and 12.8 months, respectively. Rates of infection in the ibrutinib + BR and placebo + BR arms were similar (all-grade, 70.4%; grade ≥ 3, 26.8% vs all-grade, 70.0%; grade ≥ 3, 22.6%, respectively) but exposure-adjusted analysis reveals an overall lower rate of infections with ibrutinib + BR vs placebo + BR (10.3/100 vs 11.2/100 patient-months), with similar rates of grade ≥ 3 infections (2.4/100 patient-months each arm). Rates of all-grade (grade 3/4) anemia were 22.3% (3.5%) with ibrutinib + BR and 28.9% (8.0%) with placebo + BR. Patients also required fewer transfusions with ibrutinib + BR (23%) vs placebo + BR (29%), the majority of which were red blood cell transfusions. Similar proportions of patients used growth factors in both arms (54% vs 52%, respectively). Grade 3/4 neutropenia was reported at similar rates in both arms (53.7% vs 50.5%, respectively); however, fewer patients discontinued due to treatment-related neutropenia with ibrutinib + BR (1.0%) vs placebo + BR (2.8%). Rates of thrombocytopenia were slightly higher with ibrutinib + BR (30.7%) than placebo + BR (24.0%), but rates of grade 3/4 events were similar between arms (15.0% each arm). Atrial fibrillation (AF) was observed more frequently in patients on ibrutinib + BR than placebo + BR (7.3% vs 2.8% overall and 2.8% vs 0.7% grade 3/4, respectively). However, only 4 patients with grade 3/4 AF discontinued therapy in the ibrutinib arm. No patients with grade 1/2 AF discontinued treatment. One-third of patients held ibrutinib treatment to manage AF, with all restarting at the same dose (420 mg). Median (range) time to onset was 3.0 (0.3-17.5) months with ibrutinib + BR and 2.4 (0.6-18.9) months with placebo + BR. Importantly, in those with a prior history of AF or abnormal heart rhythm, only 7/25 receiving ibrutinib + BR and 2/22 receiving placebo + BR developed AF/atrial flutter on study. The rates of any-grade bleeding were 31.0% and 14.6%, respectively, with the majority being grade 1 (77.5% and 69.0%, respectively). Low rates of grade 3/4 major bleeding were observed in the ibrutinib + BR (2.1%) and placebo + BR (1.7%) arms. Many patients (41.8% ibrutinib + BR, 41.1% placebo + BR) were receiving concomitant anticoagulant/antiplatelet medication. A low rate of treatment-related lymphocytosis was observed in both arms (7.0% ibrutinib + BR, 5.9% placebo + BR). The majority of cases resolved within 2 weeks. Conclusions In this randomized, double-blind, placebo-controlled trial, the addition of ibrutinib to BR was well tolerated and did not significantly impact the safety profile of BR. In addition, ibrutinib was associated with reduced rates of anemia and transfusional support. Consistent with its known toxicity profile, patients in the ibrutinib + BR arm had higher rates of bleeding (mostly grade 1 or 2) and AF; however, few patients discontinued therapy as a result of these AEs. A prior history of AF or abnormal heart rhythm did not lead to recurrent episodes in the majority of cases. Taken together, the results from HELIOS establish the significant efficacy of ibrutinib and also the overall positive risk-benefit profile of ibrutinib + BR. Disclosures Cramer: Janssen: Other: Travel grant, Research Funding, Speakers Bureau; Hoffman LaRoche: Other: Travel grant, Research Funding, Speakers Bureau; Astellas: Other: Travel grant; Glaxo Smith Klein/Novartis: Research Funding; Gilead: Other: Travel grant, Research Funding; Mundipharma: Other: Travel grant. Demirkan:Celgene: Other: Travel reimbursement; Amgen: Consultancy. Fraser:Hoffman LaRoche: Consultancy, Honoraria; Janssen: Honoraria, Research Funding, Speakers Bureau; Celgene: Honoraria, Research Funding. Santucci Silva:Janssen: Other: Travel reimbursement, Research Funding; GSK: Research Funding; Celgene: Research Funding; Merck: Research Funding; Novartis: Other: Travel reimbursement; Hoffman LaRoche: Other: Travel reimbursement, Research Funding. Janssens:Roche: Consultancy, Speakers Bureau; Mundipharma: Speakers Bureau; Janssen: Consultancy. Goy:Allos, Biogen Idec, Celgene, Genentech, and Millennium. Gilead: Speakers Bureau; Celgene: Consultancy, Research Funding, Speakers Bureau. Mayer:Janssen: Research Funding. Dilhuydy:Roche: Honoraria, Other: Travel reimbursement; Janssen: Honoraria, Other: Travel reimbursement; Mundipharma: Honoraria. Bartlett:Medimmune: Research Funding; Novartis: Research Funding; Pfizer: Research Funding; Genentech: Research Funding; ImaginAB: Research Funding; Astra Zeneca: Research Funding; Pharmacyclics: Research Funding; Janssen: Research Funding; Gilead: Consultancy; Seattle Genetics: Consultancy, Research Funding; Millenium: Research Funding; Celgene: Research Funding. Rule:Roche: Consultancy, Other: Travel reimbursement; Gilead: Research Funding; Celgene: Consultancy, Other: Travel reimbursement; J&J: Consultancy, Other: Travel reimbursement, Research Funding. Sun:Janssen/J&J: Employment, Equity Ownership. Phelps:Janssen/J&J: Employment, Equity Ownership. Mahler:Janssen: Employment, Other: Travel reimbursement. Salman:Janssen/J&J: Employment, Equity Ownership. Howes:Janssen/J&J: Employment, Equity Ownership. Hallek:AbbVie: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Roche: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Gilead: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Pharmacyclics: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Celgene: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Boehringher Ingelheim: Honoraria, Other: Speakers Bureau and/or Advisory Boards; Mundipharma: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Janssen: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding.

Abstract Introduction Recent results from the HELIOS phase 3 study in relapsed/refractory CLL/SLL demonstrated that the addition of ibrutinib to chemoimmunotherapy with bendamustine/rituximab (BR) leads to an 80% reduction in risk of progression or death compared with placebo + BR (Chanan-Khan et al. ASCO 2015). In addition to prolongation of progression-free survival (PFS; median not reached vs 13.3 months; hazard ratio: 0.203, 95% confidence interval: 0.150-0.276, p<0.0001), overall response rate (ORR) and rates of complete response (CR) or CR with incomplete marrow recovery (CRi) were significantly improved with ibrutinib + BR (ORR: 82.7% vs 67.8%; CR/CRi: 10.4% vs 2.8%). Here we report additional analyses on the quality of response with ibrutinib combined with BR. Methods In total, 578 patients (pts) with relapsed/refractory CLL/SLL requiring treatment were randomized 1:1 (289 per arm) to receive BR (≤ 6 cycles) with either ibrutinib (420 mg daily) or placebo. Purine analog refractoriness (yes vs no) and number of prior therapies (1 vs > 1) were stratification factors. Pts with deletion 17p (del17p; > 20% of cells) were excluded. All pts were required to have ≥ 1 abnormal lymph node (LN; defined as a measurable lesion > 1.5 cm). The primary end point was independent review committee (IRC)-assessed PFS. In this analysis, individual parameters of response (LN, spleen, overall radiology, absolute lymphocyte count [ALC], complete blood count [CBC], and bone marrow [BM]) were evaluated. Minimal residual disease (MRD) was assessed by flow cytometry using an 8-color panel (Rawstron AC, et al. Leukemia. 2007;21:956-964); MRD samples were collected at confirmation of suspected CR (bone marrow) and every 3 months thereafter (peripheral blood). Rate of MRD-negative response was defined as the proportion of pts who reached negative disease status (< 0.01%, ie, < 1 CLL cell/10,000 leukocytes) in any sample. Reported MRD rates are based on the intent-to-treat (ITT) population. Results The ORR assessed by the IRC was 82.7% with ibrutinib + BR vs 67.8% with placebo + BR (p < 0.0001), and was consistent with ORR reported by the treating physician (investigator assessed) (ORR: 86.2% vs 68.9%, p < 0.0001). However, rates of CR/CRi were higher by investigator assessment (21.4%, ibrutinib + BR vs 5.9%, placebo + BR) than IRC (10.4% vs 2.8%). The IRC employed an independent evaluation of radiological scans including stringent evaluation of LN and volumetric assessment of spleen size-the main reasons for the difference in CR/CRi rates between investigator and IRC assessment. At baseline, similar proportions of pts in each arm had bulky disease defined as LN > 5 cm (54%-58%) or abnormal spleen (~40%) as assessed by IRC. Complete resolution of previous CLL/SLL manifestations as assessed by the IRC was achieved more often in the ibrutinib + BR arm in comparison with placebo + BR for LN (34.6% vs 15.2%), spleen (56.7% vs 37.0%), overall radiology (21.1% vs 9.0%), and BM (19.7% vs 5.9%). Rates of normalization of ALC (> 90%) and CBC (> 70%) were high and similar in the 2 arms. MRD was assessed in 120 pts treated with ibrutinib + BR and 57 pts treated with placebo + BR and was negative in 37 pts and 14 pts, respectively, which corresponds with an MRD-negative response rate of 12.8% vs 4.8% for ibrutinib + BR vs placebo + BR (p = 0.0011). Investigator-determined responses by different levels of MRD are shown in Table 1. The percentage of pts with an MRD level < 1% was higher with ibrutinib + BR vs placebo + BR (32.2% vs 11.8%). Moreover, the percentage of pts with an MRD level < 0.1% was higher for ibrutinib + BR vs placebo + BR (24.6% vs 7.6%) suggesting that the depth of response with ibrutinib + BR was superior. Kaplan-Meier plots by MRD level (Figure 1) show that a lower MRD level was associated with a longer PFS. However, pts in the ibrutinib + BR arm had a more sustained response at every MRD level compared with pts in the placebo + BR arm. Conclusions Pts treated with ibrutinib + BR showed not only a higher ORR, but also a greater depth of response, with more CRs and a higher rate of resolution of LN, spleen, and BM involvement. Furthermore, the rate and depth of MRD negativity was improved, and appeared to last longer in pts treated with ibrutinib + BR compared with pts receiving placebo + BR. With a median follow up of 17 months in the ibrutinib + BR arm, no MRD-negative pts and few MRD-positive pts had progressed, thus evaluating a trend in PFS with MRD negativity is currently limited in this arm. Disclosures Cramer: Gilead: Other: Travel grant, Research Funding; Glaxo Smith Klein/Novartis: Research Funding; Astellas: Other: Travel grant; Mundipharma: Other: Travel grant; Janssen: Other: Travel grant, Research Funding, Speakers Bureau; Hoffman LaRoche: Other: Travel grant, Research Funding, Speakers Bureau. Off Label Use: Combination of bendamustine, obinutuzumab and ibrutinib for treatment of CLL. Fraser:Hoffman LaRoche: Consultancy, Honoraria; Janssen: Honoraria, Research Funding, Speakers Bureau; Celgene: Honoraria, Research Funding. Demirkan:Amgen: Consultancy; Celgene: Other: Travel reimbursement. Santucci Silva:Merck: Research Funding; Celgene: Research Funding; GSK: Research Funding; Janssen: Other: Travel reimbursement, Research Funding; Hoffman LaRoche: Other: Travel reimbursement, Research Funding; Novartis: Other: Travel reimbursement. Janssens:Mundipharma: Speakers Bureau; Roche: Consultancy, Speakers Bureau; Janssen: Consultancy. Goy:Allos, Biogen Idec, Celgene, Genentech, and Millennium. Gilead: Speakers Bureau; Celgene: Consultancy, Research Funding, Speakers Bureau. Mayer:Janssen: Research Funding. Dilhuydy:Roche: Honoraria, Other: Travel reimbursement; Janssen: Honoraria, Other: Travel reimbursement; Mundipharma: Honoraria. Bartlett:Millenium: Research Funding; Medimmune: Research Funding; Novartis: Research Funding; Pfizer: Research Funding; Genentech: Research Funding; ImaginAB: Research Funding; Astra Zeneca: Research Funding; Pharmacyclics: Research Funding; Janssen: Research Funding; Gilead: Consultancy; Seattle Genetics: Consultancy, Research Funding; Celgene: Research Funding. Rule:Roche: Consultancy, Other: Travel reimbursement; J&J: Consultancy, Other: Travel reimbursement, Research Funding; Celgene: Consultancy, Other: Travel reimbursement; Gilead: Research Funding. Sun:Janssen/J&J: Employment, Equity Ownership. Phelps:Janssen/J&J: Employment, Equity Ownership. Mahler:Janssen: Employment, Other: Travel reimbursement. Salman:Janssen/J&J: Employment, Equity Ownership. Schaffer:Janssen: Employment. Balasubramanian:Pharmacyclics LLC, an AbbVie Company: Equity Ownership; Janssen: Employment, Equity Ownership. Howes:Janssen/J&J: Employment, Equity Ownership. Hallek:AbbVie: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Celgene: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Pharmacyclics: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Gilead: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Boehringher Ingelheim: Honoraria, Other: Speakers Bureau and/or Advisory Boards; Roche: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Mundipharma: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Janssen: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding.

Abstract Introduction Ibrutinib is a first-in-class, once-daily, oral, covalent inhibitor of BTK that has excellent single-agent activity in patients with previously treated CLL/SLL, based on results of published clinical studies. In the HELIOS trial, addition of ibrutinib to BR resulted in an 80% reduction in disease progression or death and confirmed for the first time, in a randomized setting, the benefit of ibrutinib-based therapy compared with standard chemoimmunotherapy (CIT) in previously treated patients (Chanan-Khan et al. ASCO 2015). In patients with CLL or SLL, deletion 17p (del17p) and 11q (del11q), complex karyotype, unmutated IgVH, and elevated ZAP70 are known high-risk prognostic factors. The current analysis reports on the efficacy of ibrutinib + BR vs placebo + BR in patients in the HELIOS trial with relevant high-risk biomarkers. Methods HELIOS is a randomized, double-blind, placebo-controlled, phase 3 study. Patients with active CLL/SLL following ≥ 1 prior therapy were randomized 1:1 to receive BR (≤ 6 cycles) with either ibrutinib (420 mg daily) (n = 289) or placebo (n = 289). Patients with del17p (> 20% of cells) were excluded. Ninety patients in the placebo arm with independent review committee (IRC)-confirmed progressive disease crossed over to ibrutinib, per protocol amendment. The primary end point was IRC-assessed progression-free survival (PFS), and overall survival (OS) was a secondary end point. A total of 287 patients in each arm had data available for at least 1 biomarker, and this population was used for the biomarker analyses. Correlation of biological risk factors at baseline with PFS and OS was analyzed using Kaplan-Meier analysis and curves compared using log-rank tests. Hazard ratios (HRs) were estimated using univariate Cox proportional hazards models. Results At a median follow-up of 17 months, IRC-assessed PFS was significantly longer with ibrutinib + BR vs placebo + BR in the overall study population (median not reached vs 13.3 months, respectively; HR: 0.203; 95% CI: 0.150-0.276; p < 0.0001). All subgroups of patients, including those with adverse prognostic parameters, e.g., del11q, complex karyotype, unmutated IgVH and elevated ZAP70 levels, had a significantly longer PFS with the addition of ibrutinib to BR as compared with placebo + BR (Table 1). As expected, each of these adverse prognostic parameters had a negative impact on PFS in the placebo + BR arm, e.g., the median PFS was shortest in patients with complex karyotype [8.5 months vs 13.8 months in patients without complex karyotype] and in patients with unmutated IgVH (11.3 months vs 22.1 months in patients with mutated IgVH). Interestingly, in the ibrutinib + BR arm, the adverse impact of these risk factors could not be detected (median PFS not reached irrespective of presence of risk factors). For example, in Figure 1 showing the PFS curves stratified by both del11q status and treatment, the outcome for patients in the ibrutinib + BR arm with del11q was similar to those without, with a trend toward better outcome in the del11q patients (e.g., longer PFS - not reached vs 24.9 months), unlike for patients in the placebo + BR arm (11.01 months vs 13.86 months). In patients with del11q, unmutated IgVH, or elevated ZAP70, there were also statistically significant benefits in OS for those receiving ibrutinib + BR vs placebo + BR (del11q: HR: 0.326, 95% confidence interval [CI], 0.122-0.870; p = 0.025; unmutated IgVH: HR: 0.515, 95% CI, 0.298-0.890: p = 0.017; elevated ZAP70, HR 0.536, 95% CI, 0.289-0.994: p = 0.048). Addition of ibrutinib also increased PFS in patient subgroups with other cytogenetic or clinical prognostic markers (such as del13q or bulky disease) compared with placebo. Conclusions All subgroups of patients, irrespective of adverse risk factors, such as del11q, complex karyotype, elevated ZAP70, and unmutated IgVH, benefit from the addition of ibrutinib to BR compared with placebo + BR. The negative impact of these known risk factors is apparent in patients in the placebo + BR arm, but is not seen in patients in the ibrutinib + BR arm. These results suggest that ibrutinib + BR is a suitable treatment regimen for all patients with previously treated CLL/SLL, including those with high-risk prognostic markers. Disclosures Cramer: Janssen: Other: Travel grant, Research Funding, Speakers Bureau; Hoffman LaRoche: Other: Travel grant, Research Funding, Speakers Bureau; Mundipharma: Other: Travel grant; Glaxo Smith Klein/Novartis: Research Funding; Astellas: Other: Travel grant; Gilead: Other: Travel grant, Research Funding. Fraser:Janssen: Honoraria, Research Funding, Speakers Bureau; Hoffman LaRoche: Consultancy, Honoraria; Celgene: Honoraria, Research Funding. Santucci Silva:Janssen: Other: Travel reimbursement, Research Funding; GSK: Research Funding; Celgene: Research Funding; Merck: Research Funding; Novartis: Other: Travel reimbursement; Hoffman LaRoche: Other: Travel reimbursement, Research Funding. Dilhuydy:Roche: Honoraria, Other: Travel reimbursement; Janssen: Honoraria, Other: Travel reimbursement; Mundipharma: Honoraria. Goy:Allos, Biogen Idec, Celgene, Genentech, and Millennium. Gilead: Speakers Bureau; Celgene: Consultancy, Research Funding, Speakers Bureau. Mato:Celgene: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding; Gilead: Consultancy, Other: Travel, Accommodations, Expenses; Pharmacyclics LLC, an AbbVie Company: Consultancy, Other: Travel, Accommodations, Expenses; TA Therapeutics: Research Funding. Damle:Janssen: Employment. Phelps:Janssen/J&J: Employment, Equity Ownership. Mahler:Janssen: Employment, Other: Travel reimbursement. Salman:Janssen/J&J: Employment, Equity Ownership. Schaffer:Janssen: Employment. Howes:Janssen/J&J: Employment, Equity Ownership. Balasubramanian:Pharmacyclics LLC, an AbbVie Company: Equity Ownership; Janssen: Employment, Equity Ownership.

Abstract Abstract 2799 Background: Aurora A kinase (AAK) is important in a diverse set of mitotic processes and is amplified or overexpressed in a number of heme-lymphatic malignancies. MLN8237 is an investigational, orally administered, selective AAK inhibitor in clinical development for the treatment of hematologic and solid tumors. This multicenter study (NCT00697346) is the first phase 1 program to assess safety and pharmacology of MLN8237 in patients with advanced hematologic malignancies. Methods: Eligible patients were aged ≥18 yr, had response-evaluable, relapsed or refractory hematologic malignancies, and had ECOG performance status 0–2; there was no restriction on the number of prior therapies, but prior allogeneic transplant was excluded. Patients received escalating doses of MLN8237 as powder-in-capsule formulation in a 3+3 design. Endpoints included safety, dose-limiting toxicity (DLT), maximum tolerated dose (MTD), pharmacokinetics, and response. Results: Twenty-eight patients were included; median age was 62 yr (range 41–74), 50% were male, 86% were white, and 43% had prior transplant. Diagnoses were non-Hodgkin's lymphoma (68%), including diffuse large B-cell (DLBCL), mantle cell, follicular, and small lymphocytic lymphoma; multiple myeloma (29%); and chronic lymphocytic leukemia (4%). Seventy-nine percent of patients had received ≥3 prior therapies. Patients initially received a 21-day treatment schedule of MLN8237 25 or 35 mg (BID loading dose on Day 1, then QD on Days 2–21) followed by a 7-day rest period (28-day cycles). Based on results with the first two cohorts, subsequent cohorts received a 14-day treatment schedule of MLN8237 35, 45, 65, or 90 mg (BID loading dose on Day 1, then QD on Days 2–14) followed by a 14-day rest period (28-day cycles). Median number of cycles administered was 2 (range 1–14+). After escalation to 90 mg (maximum administered dose), two DLTs per cohort led to de-escalation to 65 mg and then 45 mg, which was the MTD on the 14-day schedule. The most common treatment-related adverse events (AEs) were neutropenia (46%), thrombocytopenia (36%), and asthenic conditions (32%); grade ≥3 treatment-related AEs were reported in 14 (50%) patients, and 13 (46%) had a serious AE. DLTs included grade 3–4 myelosuppression associated with infection or delay in treatment, which were generally manageable by reduction in dose or schedule. AEs were generally reversible and manageable, although 5 (18%) patients discontinued due to AEs. Three patients died, from causes (renal failure; airway obstruction; progressive large cell lymphoma) not considered related to MLN8237. Following multiple doses, an overall median Tmax of 2 hr, a mean t1/2 of 23 hr, and a peak/trough ratio of 5 were observed. The geometric mean of steady-state AUC increased from 19,534 to 30,811 nM*hr when the daily dose was increased from 25 to 65 mg. With the 14-day schedule, antitumor activity was observed in a patient with relapsed DLBCL treated with 65 mg and reduced to 45 mg, who enrolled after disease progression following ifosfamide-carboplatin-etoposide (ICE) salvage therapy. A durable PR coupled with resolution of B symptoms sustained for >1 yr was observed in a patient with post-transplant grade 3B follicular lymphoma treated with 35 mg, escalated per protocol to 45 mg and then 65 mg. Stable disease (SD; 5 months) was observed in a patient with myeloma treated at 90 mg. Conclusions: MLN8237 toxicities were consistent with AAK inhibition in proliferating tissue (chiefly bone marrow), and were generally manageable. The MTD was 45 mg on the 14-day schedule in these patients with advanced hematologic malignancies. Antitumor activity was observed, and repeat cycles were tolerable over 6–12 months in some patients who achieved PR or SD. The results support further investigation of MLN8237 in heme-lymphatic malignancies, and ongoing clinical development includes alternative schedules and formulations. Disclosures: Padmanabhan: Millennium Pharmaceuticals, Inc.: Consultancy, Research Funding. Off Label Use: Investigational agent in clinical development for the treatment of advanced hematologic malignancies. Shea:Millennium Pharmaceuticals, Inc: Consultancy, Research Funding. Vose:Millennium Pharmaceuticals, Inc.: Research Funding. Goy:Millennium Pharmaceuticals, Inc., Celgene, GSK, Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Zhou:Millennium Pharmaceuticals, Inc.: Employment. Liu:Millennium Pharmaceuticals, Inc.: Employment. Fingert:Millennium Pharmaceuticals, Inc.: Employment, Equity Ownership. Fowler:Millennium Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Honoraria, Research Funding; Cephalon: Research Funding; Genentech: Honoraria, Research Funding; Celgene: Honoraria.

Abstract INTRODUCTION: PR-171 is a novel, irreversible proteasome inhibitor under investigation for the treatment of hematological malignancies. In preclinical studies, PR-171 was well tolerated in rats and monkeys when given daily × 5 (QDx5), every two weeks. Proteasome inhibition determined in blood and other tissues one hour after dosing at the maximum tolerated dose (MTD) was >80%. Despite the irreversible mechanism of action, the half-life of recovery of proteasome inhibition in tissues was approximately 24 hours. PR-171 was effective in suppression of tumor growth in xenograft studies in mice when administered QDx2 every week for three weeks. Two phase I dose-escalation studies have been initiated, aimed at determining the safety, tolerability, and clinical response to PR-171. METHODS: Two different dose-intensive schedules were employed in these phase I studies. In PX-171-001, PR-171 was administered on a two week cycle, QDx5 with nine days rest, while in PX-171-002, PR-171 was administered on a four week cycle, QDx2 weekly for three weeks with 12 days rest. The objective of these studies was to evaluate the safety and effectiveness of single-agent PR-171 administered according to a modified Fibonacci dose escalation scheme in cohorts of three. Patients with multiple myeloma (MM), non-Hodgkin Lymphoma (NHL), Hodgkin disease, or Waldenstrom’s Macroglobulinemia who received two or more prior treatments were eligible. RESULTS: Both studies were initiated with a dose of 1.2 mg/m2. Thus far, a total of 15 and 23 subjects have been enrolled in PX-171–001 and -002, respectively. PR-171 has been well tolerated at the highest doses thus far, 8.4 and 15 mg/m2, respectively. Proteasome inhibition in whole blood at the highest dose levels exceeded 75%, and in peripheral blood mononuclear cells inhibition exceeded 65%, one hour after the first dose. There have been no dose-limiting toxicities, no adverse events (AEs) considered probably related to study medication, no dose-related increases in the incidence or severity of AEs, and no incidence of painful peripheral neuropathy on either study. Although the MTD has not yet been identified on either study, preliminary evidence of efficacy has been observed with reduction in myeloma paraprotein levels and symptomatic improvement in patients on both protocols. Eleven subjects remain on study with stable disease (SD), which has been observed in MM and NHL patients on both studies, lasting up to eight months. CONCLUSION: PR-171 is well-tolerated in relapsed and refractory MM and NHL patients at proteasome inhibition levels of more than 75%. Several subjects have achieved long-lasting SD, reduction in paraprotein levels or symptomatic improvement. Further data from these ongoing trials will be discussed at the meeting.

Abstract Background: Patients (pts) with refractory aggressive non-Hodgkin lymphoma (NHL) have poor outcomes with currently available therapies, with a complete response (CR) rate of 8%, a partial response (PR) rate of 18%, and median overall survival (OS) of 6.6 months (mo) as demonstrated in the 635 pt SCHOLAR-1 meta-analysis (Crump, ASCO 2016; abstract 7516). ZUMA-1 is the first multicenter trial of anti-CD19 chimeric antigen receptor (CAR) T cells in refractory, aggressive NHL (NCT02348216). The phase 1 portion of ZUMA-1 showed ongoing CRs at 12+ mos in 43% of pts (Locke, ESMO 2016; abstract 1048O). The pivotal phase 2 portion of ZUMA-1 comprises 2 cohorts based on tumor type: DLBCL (cohort 1) and primary mediastinal B-cell lymphoma or transformed follicular lymphoma (cohort 2). Here, we present results of a prespecified interim analysis from cohort 1. Methods: Pts received a target dose of 2 × 106 anti-CD19 CAR T cells/kg after a low-dose conditioning regimen of cyclophosphamide (500 mg/m2) and fludarabine (30 mg/m2) daily for 3 days. The primary endpoint is objective response rate (ORR) per 2007 IWG criteria. Key secondary endpoints include duration of response, frequency of adverse events (AEs), and levels of CAR T cells and serum cytokines. Key inclusion criteria include age ≥18 years, ECOG performance status (PS) 0-1, and refractory disease defined as progressive disease or stable disease as best response to last line of therapy, or disease progression ≤12 mos after autologous stem cell transplant (ASCT). Pts must have received a prior anti-CD20 antibody and an anthracycline-containing regimen. A prespecified interim analysis was to be conducted to determine early efficacy with a nominal alpha level of 0.017 in 50 treated pts in cohort 1 with a minimum follow-up of 3 mos. Results: In total, 111 pts from 22 institutions were enrolled and leukapheresed, and 101 pts received KTE-C19. As of August 24, 2016, 51 pts in cohort 1 were eligible for analysis. Median age was 58 years (range, 25-76), 73% were male, 71% had ECOG PS 1, 78% were refractory to ≥2 lines of therapy, 20% relapsed ≤12 mos of ASCT, and 61% were treated with ≥3 lines of prior therapy. KTE-C19 was successfully manufactured in 99% of pts enrolled. Average turnaround time from apheresis to receipt of KTE-C19 at the clinical site was 17.4 days. With an ORR of 76%, the study met the primary endpoint (P<0.0001; exact binomial test comparing observed ORR to a historical control assumption of 20%), with 47% CRs and 29% PRs. 92% of responses occurred within the 1st mo, and 39% of pts had ongoing responses (CR in 33%) at 3 mos. Responses were seen across key covariates, including refractory subgroup (refractory to chemotherapy=76%, relapse post ASCT=80%). Kaplan-Meier estimates of progression-free survival at 1 and 3 mos were 92% and 56%, respectively. The most common grade ≥3 treatment-emergent AEs were neutropenia (67%), anemia (39%), thrombocytopenia (29%), febrile neutropenia (27%), and encephalopathy (24%). Grade ≥3 cytokine release syndrome (CRS) and neurologic events occurred in 20% and 29% of pts, respectively. There was 1 grade 5 KTE-C19-related event of hemophagocytic lymphohistiocytosis. CAR T cells expanded within 14 days of KTE-C19 infusion, and peak expansion was associated with ongoing response at mo 3 (P=0.008). Pts who developed grade ≥3 neurological events had increased serum levels of IL-15 (P=0.0002), IL-6 (P=0.003); IL-10 (P=0.009) and IP-10 (P=0.0003). Cytokines/chemokines returned to baseline levels in most pts by day 28. Data from 93 pts with at least 1 mo of follow-up at the data cutoff will be presented. Conclusions: ZUMA-1 is the first reported multicenter trial of CAR T cell therapy in pts with refractory aggressive NHL. KTE-C19 induced a nearly 6-fold higher CR rate compared to historical outcomes in SCHOLAR-1. Efficacy strongly associated with peak CAR T levels. Central manufacturing, logistics, and AE management were successfully implemented across 22 sites, most with no prior CAR T therapy experience. Results from cohort 2 of ZUMA-1 are also presented (Abstract #998). KTE-C19 demonstrated significant clinical benefit in pts with no curative treatment options. Supported in part by funding from The Leukemia & Lymphoma Society Therapy Acceleration Program®. Drs Neelapu and Locke contributed equally to this study. Disclosures Neelapu: Kite Pharma: Membership on an entity's Board of Directors or advisory committees, Research Funding. Locke:Kite: Membership on an entity's Board of Directors or advisory committees. Miklos:pharmacyclics: Research Funding; Kite Pharma: Research Funding; Roche: Research Funding; Novartis: Research Funding. Jacobson:Kite: Membership on an entity's Board of Directors or advisory committees. Siddiqi:Pharmacyclics: Speakers Bureau; Janssen: Speakers Bureau; Seattle Genetics: Speakers Bureau. Lin:Mayo Clinic: Employment; Janssen: Research Funding. Timmerman:Bristol-Myers Squibb, Kite Pharma, Valor Biopharmaceuticals, Janssen: Research Funding; Seattle Genetics, Genmab, Celgene: Consultancy, Honoraria. Goy:COTA: Membership on an entity's Board of Directors or advisory committees; Janssen/Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Research funding for clinical trials through institution, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Research funding for clinical trials through institution; Acerta: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genentech: Other: Research funding for clinical trials through institution. Smith:Abbvie: Research Funding; Celgene: Honoraria; Spectrum: Honoraria; Genentech: Honoraria. Deol:Jazz Pharmaceuticals: Consultancy. Avivi:Tel Aviv Sourasky Medical center: Consultancy, Other: consultancy to :BMS Roche. Westin:Genentech: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Spectrum: Membership on an entity's Board of Directors or advisory committees; ProNAi: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Chavez:Janssen: Speakers Bureau. Levy:Kite Pharma: Consultancy; Five Prime Therapeutics: Consultancy; Innate Pharma: Consultancy; Beigene: Consultancy; Corvus: Consultancy; Dynavax: Research Funding; Pharmacyclics: Research Funding. Reagan:Seattle Genetics: Research Funding. Bot:Kite Pharma: Employment, Equity Ownership. Rossi:Kite Pharma: Employment, Equity Ownership. Navale:Kite Pharma: Employment, Equity Ownership. Jiang:Kite Pharma: Employment, Equity Ownership. Aycock:Kite Pharma: Employment, Equity Ownership. Elias:Kite: Employment, Equity Ownership. Wiezorek:Kite Pharma: Employment, Equity Ownership. Go:Kite Pharma: Employment, Equity Ownership.

Abstract Abstract 905 Introduction: Though dose-intensive strategies using chemoimmunotherapy have significantly improved mantle cell lymphoma (MCL) outcomes with prolonged progression-free survival (PFS), most patients still relapse over time. In the relapsed setting, MCL patients often develop chemoresistance and have a poor overall prognosis. The immunomodulatory agent lenalidomide has demonstrated tumoricidal and antiproliferative effects in MCL and clinical activity and safety in multiple phase II studies in aggressive non-Hodgkin's lymphoma. The objective of the MCL-001 “EMERGE” study was to examine the safety and efficacy of single-agent lenalidomide in subjects with MCL who relapsed or were refractory to bortezomib. Methods: This phase II, multicenter, single-arm, open-label study examined single-agent lenalidomide administered at 25 mg/d PO on days 1–21 of a 28-day cycle until disease progression, unacceptable toxicity, or voluntary withdrawal. The subjects were required to have had prior treatment with rituximab, cyclophosphamide and anthracycline (or mitoxantrone), and to have relapsed or progressed (<12 months) after or were refractory to bortezomib. The primary endpoints were overall response rate (ORR) and duration of response (DOR); secondary endpoints included complete response (CR), PFS, time to progression (TTP), overall survival (OS) and safety. Efficacy data were measured by investigators and an independent central review committee according to modified International Working Group criteria and analyzed by SAS. Results: 134 subjects with relapsed or refractory MCL who were heavily pretreated (no limitation in number of prior therapies) were enrolled. The median age was 67 y (range, 43–83), two-thirds of them being 65 y or older and 93% with advanced stage disease (stage III-IV). The median number of prior therapies was 4 (range, 2– 10) with 78% of subjects having received ≥ 3 prior lines of treatment. The ORR to single-agent lenalidomide was 28% (CR/CRu 8%; Table 1) by independent central review, with a median DOR of 16.6 mo (95% CI, 7.7–26.7; Figure 1). The ORR was 32% (CR/CRu 16%) by investigator assessment, with a median DOR of 18.5 mo. Median time to response (central review) was 2.2 mo (3.7 mo to achieve CR). The median PFS was 4.0 mo (95% CI, 3.6–5.6); median OS was 19.0 mo (95% CI, 12.5–23.9). Subjects received an average dose of 20 mg/d of lenalidomide. Lenalidomide was dose reduced in 38% of subjects; treatment discontinuation due to an adverse event (AE; primarily myelosuppression) was reported in 19% of subjects. The most common grade 3/4 AEs were neutropenia (43%), thrombocytopenia (28%), anemia (11%), pneumonia (8%) and fatigue (7%). Other AEs (any grade) included tumor flare reaction (13 subjects, 10%), deep vein thrombosis (5 subjects, 4%), pulmonary embolism (3 subjects, 2%) and invasive second primary malignancies (3 subjects, 2%). Conclusions: The EMERGE study demonstrated rapid and durable efficacy of lenalidomide in MCL subjects who relapsed or progressed after or were refractory to bortezomib. These results in heavily pretreated MCL subjects (median of 4 prior treatments), and with an expected toxicity profile support single-agent lenalidomide in subjects with relapsed or refractory MCL after bortezomib. Disclosures: Goy: Pfizer: Advisory board member, Advisory board member Other; Seattle Genetics: Advisory board member Other; J&J: Advisory board member, Advisory board member Other; Pharmacyclics: Advisory board member, Advisory board member Other; Millenium: Advisory board member, Advisory board member Other, Speakers Bureau; Celgene: Advisory board member Other. Off Label Use: This is a phase 2 clinical study of safety and efficacy for lenalidomide in patients with MCL. Sinha:Celgene: Research Funding. Williams:Celgene: Clincial Trial Research Support, Advisory Boards, Data Safety Committee Member, Consultant Other, Consultancy. Drach:Celgene: Speakers Bureau; Janssen: Speakers Bureau; Roche: Research Funding. Ramchandren:Seattle Genetics: Speakers Bureau. Herbrecht:Pfizer: Advisory board member Other. Zhang:Celgene: Employment. Cicero:Celgene: Employment. Fu:Celgene: Employment. Witzig:Celgene : Research Funding.