Citations

Abstract Introduction Few treatments options are available for patients (pts) with relapsed/refractory multiple myeloma (RRMM) who have previously been treated with lenalidomide (LEN) and bortezomib (BORT), and their prognosis is poor. Pomalidomide (POM) is a distinct IMiD® immunomodulatory agent with a mechanism of action consisting of direct anti-myeloma, stromal-support inhibitory, and immunomodulatory effects. In randomized phase 2 and 3 trials (MM-002 and MM-003), POM plus low-dose dexamethasone (POM+LoDEX) demonstrated marked efficacy in RRMM pts who had received multiple prior therapies, including LEN and BORT. This side-by-side analysis presents the most recent survival and safety data from these trials. Methods The MM-002 and MM-003 trials enrolled pts with ≥ 2 prior therapies, including LEN and BORT. In MM-002, pts received POM (4 mg/day on days 1–21 of each 28-day cycle) alone or in combination with LoDEX (40 mg/week). In MM-003, pts were randomized 2:1 to receive POM+LoDEX or high-dose DEX alone (HiDEX) (40 mg/days 1–4, 9–12, 17–20 in a 28-day cycle); HiDEX was chosen as the comparator to isolate the effects of POM, as at the time of trial design it was the standard salvage therapy for heavily pretreated pts. Thromboprophylaxis was required for all pts treated with POM and pts at high risk of developing venous thromboembolism. Data cutoff was February 1, 2013 for MM-002 and March 1, 2013 for MM-003. The primary endpoint in both trials was progression-free survival (PFS). Secondary endpoints included overall survival (OS), response rates, duration of response, and safety. Results In each study, pts had received a median of 5 prior therapies (range 1-17), and all pts had received prior LEN and BORT. In MM-002, 113 pts were treated with POM+LoDEX and 108 were treated with POM alone (60% of POM alone pts subsequently received DEX). A total of 79% of pts were LEN refractory; 62% were refractory to both LEN and BORT; and 35% had received LEN as their last prior therapy. With a median follow-up of 14.2 months (mos), median PFS was 4.2 mos, OS was 16.5 mos, and overall response rate (ORR, defined as at least a partial response) was 33% with POM+LoDEX (Table 1). In MM-003, 302 pts were treated with POM+LoDEX and 153 pts were treated with HiDEX (50% of HiDEX pts subsequently received POM). A total of 94% of pts were LEN refractory; 74% were both LEN and BORT refractory; and 29% had received LEN as their last prior therapy. Survival outcomes were similar in MM-003; with a median follow-up of 10 mos, median PFS was 4.0 mos, OS was 12.7 mos, and ORR was 31% with POM+LoDEX. In both trials, LEN as last prior therapy did not impact response, PFS, or OS vs the overall population. Commonly observed adverse events (AEs) are presented in Table 2 for pts treated with POM+LoDEX. Grade 3 and 4 neutropenia was 28% and 13% in MM-002, and 26% and 22% in MM-003 for the POM+LoDEX arms, respectively. AEs were generally manageable for POM+LoDEX in MM-002 and MM-003 with dose interruptions (67% for both) and reductions (29% and 26%, respectively), and standard supportive care, including growth factor support (46% and 43%), red blood cell transfusions (45% and 49%), platelet transfusions (14% and 20%), and anti-infective agents (89% in both trials). Rates of POM discontinuation due to treatment-related AEs were low (2–4% with POM+LoDEX). In MM-002 and MM-003, 49% and 51% of pts in the POM+LoDEX arms experienced neutropenia of any grade. With appropriate AE management, 9% and 23% had dose interruptions, 4% and 8% had dose reductions, and 1 pt in both MM-002 and MM-003 discontinued due to neutropenia. Febrile neutropenia developed in 3% and 10% of pts; 1% and 4% had dose interruptions, 0% and 2% had dose reductions, and no pts discontinued due to febrile neutropenia in the MM-002 and MM-003 studies, respectively. The majority of infections occurred in the absence of neutropenia of any grade (54% in MM-002 and 66% in MM-003). The rate of POM discontinuation due to infection was low (1% in MM-002 and 2% in MM-003). Conclusion In both the MM-002 and MM-003 trials, POM+LoDEX consistently extended PFS in advanced RRMM pts. PFS, OS, and ORR were not negatively impacted in patients who were refractory to LEN or BORT, even as last prior therapy. Both trials demonstrated that with dose modifications and supportive care POM was well tolerated, leading to few discontinuations. POM+LoDEX should be considered a standard of care for pts with advanced RRMM who have exhausted LEN and BORT. Disclosures: Siegel: Celgene Corporation: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Onyx: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Millennium: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau. Richardson:Millennium: Membership on an entity’s Board of Directors or advisory committees; Johnson & Johnson: Membership on an entity’s Board of Directors or advisory committees; Celgene Corporation: Membership on an entity’s Board of Directors or advisory committees. Dimopoulos:Celgene Corporation: Honoraria, Membership on an entity’s Board of Directors or advisory committees. Chen:Celgene Corporation: Consultancy, Honoraria, Research Funding. Song:Celgene Corporation: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau. Vij:Onyx: Consultancy, Research Funding; Millenium: Speakers Bureau; Celgene Corporation: Consultancy, Research Funding, Speakers Bureau. Bahlis:Celgene Corporation: Consultancy, Honoraria, Research Funding. Baz:Millenium: Research Funding; Bristol Myers Squibb: Research Funding; Novartis: Research Funding; Karyopharm: Research Funding; Sanofi: Research Funding; Celgene Corporation: Research Funding. Hofmeister:Celgene Corporation: Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau. Weisel:Celgene Corporation: Consultancy, Honoraria, Research Funding. Jagannath:Millennium: Honoraria; Celgene Corporation: Honoraria. Lonial:Millennium: Consultancy; Novartis: Consultancy; Bristol Myers Squibb: Consultancy; Sanofi: Consultancy; Onyx: Consultancy; Celgene Corporation: Consultancy. Delforge:Celgene Corporation: Honoraria. Talpaz:Ariad, Sanofi, Novartis: Membership on an entity’s Board of Directors or advisory committees; Ariad, Novartis, BMS, Pfizer: Speakers Bureau; Ariad, BMS, Sanofi, INCYTE: Research Funding. Moreau:Celgene Corporation: Honoraria, Speakers Bureau. San Miguel:Jansen, Celgene Corporation, Onyx, Novartis, Millenium: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees. Karlin:Janssen: Honoraria; Celgene Corporation: Consultancy, Expert board committee Other, Honoraria. Goldschmidt:Celgene Corporation, Janssen, Novartis: Consultancy, Honoraria, Research Funding. Oriol:Celgene Corporation: Consultancy. Alegre:Janssen: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Celgene Corporation: Membership on an entity’s Board of Directors or advisory committees, Research Funding. Cavo:Millennium: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees; Onyx: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees; Celgene Corporation: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees. Martinez-Lopez:Celgene Corporation: Honoraria, Research Funding. Lacy:Celgene Corporation: Research Funding. Chen:Celgene Corporation: Employment, Equity Ownership. Casey:Celgene Corporation: Employment, Equity Ownership. Sternas:Celgene Corporation: Employment, Equity Ownership. Zaki:Celgene Corporation: Employment, Equity Ownership. Jacques:Celgene Corporation: Employment, Equity Ownership. Anderson:Onyx: Consultancy, Equity Ownership; Gilead: Consultancy, Equity Ownership; sanofi aventis: Consultancy, Equity Ownership; Oncopep: Consultancy, Equity Ownership; Acetylon: Consultancy, Equity Ownership; Celgene Corporation: Consultancy, Equity Ownership.

Abstract Background LGH447 is a novel, specific pan-Pim kinase inhibitor in development for the treatment of patients with multiple myeloma (MM) and other hematologic malignancies. The PIM kinase gene family encodes 3 serine/threonine protein kinases that have roles in cell cycle progression and survival. In human disease, elevated levels of Pim1 and Pim2 are associated with hematologic malignancies, with MM showing the highest level of Pim2 expression. In preclinical studies, a majority of MM cell lines proved sensitive in vitro to LGH447-mediated Pim inhibition, exhibiting a dose-dependent decrease in cell proliferation. Furthermore, LGH447 was well tolerated and demonstrated significant inhibition of tumor growth in xenograft mouse models of MM as compared with control animals, supporting the clinical development of LGH447 in MM patients. Methods Patients with relapsed/refractory MM for whom no effective treatment options exist were enrolled on this first-in-human, multicenter, open-label phase 1 dose-escalation study (CLGH447X2101). Escalating doses of single-agent LGH447 were administered orally on a continuous daily dosing schedule. Treatment continued until disease progression, unacceptable toxicity, consent withdrawal, or death. The primary objective was to estimate the maximum tolerated dose (MTD) of LGH447 administered as a single agent, orally, once daily. Secondary objectives included assessing the safety, tolerability, preliminary antimyeloma activity, and pharmacokinetic (PK) profiles of LGH447. Dose escalation followed a Bayesian logistic regression model based on dose-limiting toxicities (DLTs) occurring in cycle 1. Adverse events (AEs) were graded according to National Cancer Institute-Common Terminology Criteria for Adverse Events v4.03. Efficacy assessments were made by investigators according to International Myeloma Working Group (IMWG) uniform response criteria with modifications. Following determination of the MTD for LGH447, additional patients will be enrolled in an expansion cohort to further characterize the safety and tolerability profile of LGH447. Results At the data cutoff, 19 patients have been treated at the following doses: 70 mg (n = 5), 150 mg (n = 6), 200 mg (n = 4), 250 mg (n = 4), with enrollment ongoing in dose escalation. Median age was 66 years (range, 41-75 years). Most patients (94.7%) presented with baseline Eastern Cooperative Oncology Group performance status 0-1. Most patients (73.7%) had received ≥ 2 prior regimens (median 4; range, 1-11), 89.5% had received prior bortezomib, and 84.2% had received prior lenalidomide and/or thalidomide (68.4% and 47.4%, respectively). Ten patients are ongoing at doses between 150-250 mg, with a median duration of exposure of 6 weeks (range, 1-26.6 weeks), and 9 patients discontinued (disease progression [n = 6], AEs [n = 2], withdrawal of consent [n = 1]). There was 1 DLT consisting of grade 3 thrombocytopenia at the 200 mg dose level and no reported suspected unexpected serious AEs. The majority of AEs regardless of study drug relationship were grade 1/2. Most common grade 3/4 AEs were thrombocytopenia (31.6%), anemia (21.1%), and neutropenia (15.8%). No deaths have occurred on study. LGH447 displayed time-dependent PK with a 3- to 6-fold accumulation from day 1 to steady state (day 14). After a single oral dose, area under the curve and maximum concentration increased somewhat more than in proportion to the dose from 70 to 250 mg. Evidence of single-agent activity, as determined by investigators using IMWG criteria, has been seen in multiple patients, with best response to date being a very good partial response (VGPR). Conclusion In heavily treated patients with relapsed/refractory MM, LGH447 was generally well tolerated and exhibited evidence of single-agent efficacy in multiple patients, validating Pim kinase inhibition as a promising therapeutic rationale and supporting its further clinical development in patients with MM and other hematologic malignancies. Dose escalation is ongoing and updated results will be presented. Disclosures: Ocio: BMS: Consultancy; Arry-520: Consultancy; Pharmamar: Research Funding; Celgene: Honoraria, Research Funding; Onyx: Consultancy, Research Funding; Novartis: Honoraria. Thomas:Novartis: Research Funding; Celgene: Research Funding; Immunomedics: Research Funding; Pharmacyclics: Membership on an entity’s Board of Directors or advisory committees; Onyx: Membership on an entity’s Board of Directors or advisory committees; Millenium: Research Funding. Günther:Novartis: Consultancy, Research Funding. Lebovic:Celgene: Speakers Bureau; Allos/Spectrum: Speakers Bureau; Genentech: Speakers Bureau; Onyx: Speakers Bureau. Kumar:Onyx: Consultancy, Research Funding; Millennium: Consultancy, Research Funding; Celgene: Consultancy, Research Funding. Jakubowiak:Onyx: Consultancy, Honoraria, Speakers Bureau; Millennium: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Speakers Bureau; BMS: Consultancy, Honoraria. Song:Novartis: Employment. Xiang:Novartis: Employment. Hynds:Novartis: Employment. Vanasse:Novartis: Employment. Goh:Jannsen: Research Funding; BMS: Membership on an entity’s Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Hospira: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding.

Abstract Abstract 1875 Introduction: Carfilzomib (CFZ) is a next-generation proteasome inhibitor that has demonstrated durable single-agent antitumor activity in patients (pts) with relapsed and/or refractory multiple myeloma (R/R MM). Previously we have shown that unfavorable cytogenetic features, defined as presence of any of del 13 or hypodiploidy by metaphase cytogenetic analysis and/or del 17p13, t(4;14), t (14;16) by fluorescence in situ hybridization (FISH), did not appreciably affect overall (≥PR) and clinical benefit (≥MR) response rates (ORR and CBR) in PX-171-003-A1, a large phase 2 study of single-agent CFZ in pts with R/R MM (Jakubowiak et al. Ann Oncol. 2011;22(S4): Abstract 117). The objectives of the present analysis were to evaluate the impact of specific cytogenetic abnormalities on efficacy and treatment outcomes. Methods: Pts with unfavorable cytogenetic abnormalities (defined above) were eligible for inclusion in this analysis. All pts received CFZ at 20 mg/m2 IV on days 1, 2, 8, 9, 15, and 16 of 28-day cycles (C) and were dose-escalated to 27 mg/m2 at C2. Pts were treated for up to 12 C. Responses were assessed by International Myeloma Working Group criteria, with minimal response (MR) by European Group for Blood and Marrow Transplantation criteria. Assessments were confirmed by an Independent Review Committee (IRC). Results: A total of 234 pts were included in this analysis. Metaphase cytogenetic data were available for 203 pts (87%), and FISH data were available for 210 pts (90%); 178 pts had both (76%). Seventy-five of 234 pts (32%) had ≥1 abnormality and represented the unfavorable group in this analysis. Of these, 49 (65%) had abnormalities detected via metaphase cytogenetics, 47 (63%) by FISH, and 21 (28%) by both methods. Characteristics of pts in the unfavorable and normal/favorable groups were comparable overall, with the exception of a higher proportion of pts with International Staging System stage II/III in the unfavorable group (83% vs 64%). Response rates per the IRC, presented previously, included an ORR of 30% for pts with ≥1 abnormality compared with 23% for pts with none. The corresponding CBRs were 34% and 40%, respectively. Duration of response (DOR) and time to progression (TTP) values were 7 months (mo) (95% CI 4–9) and 4 mo (95% CI 3–6), respectively, for pts with ≥1 abnormality and 8 mo (95% CI 6–12) and 5 mo (95% CI 3–6), respectively, for pts with none. The ORRs, CBRs, and disease control rates (DCRs) according to specific cytogenetic abnormalities are presented below. Response rates were largely unaffected by the presence of specific unfavorable cytogenetic abnormalities, with the possible exceptions of trends toward a higher response rate for t(4;14) and a lower rate for t(14;16), although the latter abnormality was only noted in 3 pts. The trend for better response rates in pts with t(4;14) corresponded to a DOR of 5.6 mo (95% CI 2.8–10.2). In contrast, the DOR appeared shorter for the subgroup of pts with del 17p13 (4.6 mo, 95% CI: 3.7–Not reached). Time-to-event endpoints including TTP are being analyzed for these and the other subpopulations, and data on these will be presented, along with overall survival stratified by cytogenetic abnormality. Conclusions: CFZ demonstrated comparable response rates in pts with relapsed/refractory MM in both the absence and presence of unfavorable cytogenetic abnormalities in the 003-A1 study. Similarly, in the phase 2 PX-171-004 study, no significant difference in response rates between unfavorable and normal/favorable groups has been observed in a population of less heavily-pretreated pts with relapsed or R/R MM. Taken together, the results of these and other analyses to date suggest that responses to single-agent CFZ can be achieved in heavily pretreated pts and that overall, these responses appear not to be significantly influenced by poor prognostic cytogenetic features. Further analyses from studies with CFZ in newly diagnosed MM and in less heavily-pretreated pts are needed to determine whether a trend toward lower response rates and DOR for pts with del 17p13 is consistently observed in other populations. Disclosures: Jakubowiak: Ortho Biotech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Honoraria, Speakers Bureau; Millennium Pharmaceuticals, Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Onyx Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Exelixis: Consultancy, Honoraria. Off Label Use: Use of the investigational agent carfilzomib, proteasome inhibitor, in the treatment of relapsed and/or refractory multiple myeloma. Siegel:Millennium: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Singhal:Celgene: Speakers Bureau; Millennium: Speakers Bureau; Onyx Pharmaceuticals: Research Funding. Martin:Celgene: Honoraria; Onyx Pharmaceuticals: Consultancy. Lonial:Onyx: Consultancy; Bristol-Myers Squibb: Consultancy; Novartis: Consultancy; Celgene: Consultancy; Millennium Pharmaceuticals, Inc.: Consultancy; Merck: Consultancy. Kukreti:Celgene: Honoraria. Bahlis:Celgene: Honoraria, Speakers Bureau. Alsina:Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Allergan: Research Funding. Kunkel:Onyx Pharmaceuticals: Consultancy; Threshold: Consultancy; VLST biothech: Consultancy. Wong:Onyx Pharmaceuticals: Employment, Equity Ownership. Orlowski:Onyx Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees. Stewart:Celgene Corporation: Consultancy, Research Funding; Millenium: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Onyx: Consultancy, Research Funding. Jagannath:Millennium: Honoraria; Celgene: Honoraria; Onyx Pharmaceuticals: Honoraria; Merck: Honoraria; OrthoBiotec. Imedex: Membership on an entity's Board of Directors or advisory committees; Medicom World Wide: Membership on an entity's Board of Directors or advisory committees; Optum Health Education: Membership on an entity's Board of Directors or advisory committees; PER Group: Membership on an entity's Board of Directors or advisory committees. Wang:Onyx Pharmaceuticals: Research Funding.

Abstract Abstract 985 Introduction: CFZ is a novel and highly selective epoxyketone proteasome inhibitor currently in clinical development for the treatment of multiple myeloma (MM). Ph 1 and 2 studies with CFZ have demonstrated durable single-agent antitumor activity in pts with relapsed or refractory (R/R) MM. The present study, PX-171-003-A1, was an open-label, single-arm Ph 2b trial and enrolled patients with multiply relapsed MM whose disease was refractory (defined as <25% response on, or progression during or <60 days after completion of, therapy) to their last treatment regimen. Patients must have received ≥2 prior therapies including: 1) bortezomib (BTZ) and either thalidomide (THAL) or lenalidomide (LEN), and 2) an alkylating agent. Materials and Methods: Pts received CFZ at 20 mg/m2 on a QDx2 schedule (Days 1, 2, 8, 9, 15, and 16 every 28 days) in cycle (C) 1 and were dose escalated to 27 mg/m2 on the same schedule thereafter for up to 12 C. Pts completing 12 C were eligible to enter an extension study (PX-171-010). The primary endpoint was overall response rate (ORR) (≥ partial response [PR]). Secondary endpoints included: clinical benefit response (CBR) (ORR + Minimal response [MR]), duration of response for ≥PR (DOR), overall survival (OS), time to progression (TTP), progression free survival (PFS), and safety. Responses and progression were determined according to the International Myeloma Working Group (IMWG) criteria and were assessed and confirmed by an Independent Response Committee (IRC). Results: 266 pts were enrolled with a median duration of MM of 5.4 years including 83% whose disease had progressed on or within 60 d of last therapy and 17% whose disease had achieved <25 % response to the regimen immediately preceding study entry. Of the 266 pts enrolled pts, 257 were evaluable for response; 9 patients were considered not evaluable based on missing baseline or lacking at least one post-baseline M-protein. An ORR (≥PR) of 24% with a median DOR of 7.4 mo (range 6.2–10.3) was determined. Responses are detailed in the table. The CBR (ORR + MR) was 36%. Median DOR of pts with MRs was 6.3 months, indicating that long-term MRs were observed. An additional 32% (83 pts) achieved SD for at least 6 wks. To date, 79 pts (30%) completed ≥6 C and >11% of pts have completed all 12 C of protocol specified therapy and most have entered the extension protocol; 15 pts remain on study (all >10 C). OS and TTP data for the overall population will also be reported. The enrolled pts in this study were heavily pretreated having received a median of 5 prior lines of therapy (range 1–20, median of 13 anti-myeloma agents). 85% of pts had received at least 2 and 37% had received at least 3 drugs in the regimen just prior to entering the study. Prior anti-myeloma agents included 99.6% (265/266 pts) BTZ (median 2 prior regimens containing BTZ), 99.6% either THAL (74%) or LEN (94%), 98% corticosteroids, 91% alkylating agents, and 74% stem cell transplant; 65% of pts were refractory to BTZ at any point in time prior to study entry. The most common treatment-emergent adverse events ≥ Grade (G) 3 regardless of relationship to study drug were predominantly hematologic and included thrombocytopenia (22%), anemia (20%), lymphopenia (10%), pneumonia (8%), neutropenia (8%), fatigue (7%), hyponatremia (5%), and hypercalcemia (5%). Although 206 pts (77%) had G1/2 peripheral neuropathy (PN) at baseline, new onset PN was infrequent and G ≥3 PN occurred in <1%. Interestingly, in this subset of patients, efficacy response was nearly identical to that seen in the full study population with an ORR (≥PR) of 24%. Conclusions: Single-agent CFZ achieved durable responses in pts with R/R MM whose disease had relapsed after all available therapies including BTZ and immunomodulatory agents. The CBR and median DOR achieved with this steroid-sparing regimen establish that CFZ has the potential to offer substantial clinical benefit to patients with relapsed or refractory disease. CFZ was well-tolerated and side effects were clinically manageable with no new or unexpected toxicities observed. Importantly, exacerbation of pre-existing PN was uncommon. Cumulative side effects were not observed, allowing prolonged single-agent dosing for chronic disease control. Disclosures: Siegel: Millenium: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Martin:Celgene: Honoraria; Onyx: Consultancy. Wang:Celgene: Research Funding; Onyx: Research Funding; Millenium: Research Funding; Novartis: Research Funding. Vij:Onyx: Honoraria. Jakubowiak:Millennium Pharmaceuticals, Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria; Centocor Ortho Biotech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Exelixis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Jagannath:Millenium, OrthoBiotec, Celgene, Merck, Onyx: Honoraria; Imedex, Medicom World Wide, Optum Health Education, PER Group: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Lonial:Millennium: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Onyx: Consultancy, Research Funding. Kukreti:Celgene: Honoraria; Roche: Honoraria; Ortho Biotech: Honoraria. Alsina:Millenium: Consultancy, Research Funding; Celgene: Research Funding; Novartis: Consultancy. Zonder:Millenium: Consultancy, Honoraria, Research Funding; Cephalon: Research Funding; Celgene: Honoraria. Wong:Onyx Pharmaceuticals: Employment. Vallone:Onyx Pharmaceuticals: Employment. Chang:Onyx Pharmaceuticals: Employment. Kauffman:Onyx Pharmaceuticals: Employment. Stewart:Millennium: Consultancy; Celgene: Honoraria. Singhal:Celgene: Speakers Bureau; Takeda/Millenium: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Onyx : Research Funding.

Abstract Background: Peripheral T-cell lymphoma (PTCL) is a heterogeneous group of non-Hodgkin lymphomas associated with poor prognosis and repeated recurrence for most subtypes. Currently, anthracycline-based therapies such as cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) or CHOP-like therapies are recommended as the first-line treatment for PTCL, but the prognosis remains poor with most patients relapsing within 5 years. Thus, improved treatment strategies are still needed. Belinostat is a potent, pan-histone deacetylase inhibitor that was recently approved in the United States for the treatment of patients with relapsed or refractory PTCL (R/R PTCL). Approval was based on results from the pivotal Phase 2 BELIEF study (O'Connor et al, JCO, 2015) of belinostat in R/R PTCL, which demonstrated durable clinical benefit (objective response rate [ORR] 25.8%) and tolerability. Since belinostat (Bel) and each of the components of the CHOP regimen target different aspects of the cell cycle with different mechanisms of action, there is potential for a synergistic effect of a Bel-CHOP combination treatment regimen for patients with PTCL. Methods: Patients with PTCL received CHOP in association with 1000 mg/m2 of belinostat on various schedules, repeated every 21-days for up to 6 cycles. The cohort schema followed a traditional "3+3" dose escalation design. The objective of Part A of the study was to determine the Maximum Tolerated Dose (MTD) of the Bel-CHOP combination. Once the MTD was determined, at least 10 more patients were to be treated in the Expansion Phase (Part B). Belinostat was to be administered as a 1000 mg/m2 IV infusion once daily for up to 5 days, depending on the assigned cohort (Fig 1). The starting cohort was Cohort 3 (CHOP + 1000 mg/m2 of daily belinostat on Days 1-3). Patients received primary prophylaxis with growth factor (G-CSF) support. Dose-limiting toxicities (DLT) were considered during the 1st cycle and included: non-hematological toxicity Grades 3-4, platelet count &lt; 25 X 109/L at any time or ANC &lt; 0.5 X 109/L lasting more than 7 days despite G-CSF administration. The primary endpoint of the study was the determination of the MTD of the Bel-CHOP combination. Secondary endpoints included safety, tolerability and ORR (complete response [CR] + partial response [PR]) and pharmacokinetics. Results: A total of 23 patients were enrolled in the study, 11 of which were treated in Part A. One patient in Part A was deemed inevaluable because the patient died due to disease progression before completing Cycle 1. The MTD was determined to be 1000 mg/m2 on Days 1-5 (Cohort 5); 12 more patients were then treated at this dose level (Part B). The only DLT experienced in the study was in Cohort 3 (Grade 3 Nausea and Vomiting). At the time of this abstract, 18/23 patients (78%) have completed all 6 cycles of Bel-CHOP, with 87% completing at least 4 cycles. Ten patients (43%) had at least one serious adverse event (SAE) and 18 (78%) had at least one Grade 3 or 4 adverse event (AE). The most frequent Grade 3/4 AEs were hematological in nature: neutrophil count decreased (26%), anemia (22%), neutropenia (17%) and white blood cell count decreased (17%). The ORR for the18 patients that have completed an End of Study Visit is 89% (16/18), with the vast majority achieving a CR [72% (n=13)], and 17% (n=3) a PR. Progressive disease was reported in 2 patients. Conclusions: These results demonstrate that the combination of belinostat with CHOP (Bel-CHOP) is well tolerated, with all components of CHOP and belinostat being given at their standard therapeutic doses. The rates of AEs were consistent with those typically reported with CHOP alone, and clinical activity was demonstrated with a response rate of 89% based on 18 evaluable patients. Thus, Bel-CHOP is a promising new regimen in PTCL that will be further tested in a Phase 3 randomized trial. Table. Table. Figure 1. Summary of Demographic and Baseline Characteristics AITL= angioimmunoblastic T-cell lymphoma; ALCL =anaplastic large-cell lymphoma; ALK = anaplastic lymphoma kinase; NOS = not otherwise specified Figure 1. Summary of Demographic and Baseline Characteristics. / AITL= angioimmunoblastic T-cell lymphoma; ALCL =anaplastic large-cell lymphoma; ALK = anaplastic lymphoma kinase; NOS = not otherwise specified Disclosures Barta: Seattle Genetics: Research Funding. Bhat:Spectrum Pharmaceuticals, Inc: Employment. Song:Spectrum Pharmaceutical, Inc: Employment. Choi:Apectrum Pharmaceuticals, Inc: Employment. Allen:Spectrum Pharmaceuticals, Inc: Employment. Foss:Spectrum Pharmaceuticals; Celgene: Seattle Genetics: Infinity; Millenium: Consultancy, Honoraria, Research Funding, Speakers Bureau.

Abstract Both genome wide association studies (GWAS) of common variation and exome wide association studies (EXWAS) of rare variation have successfully identified disease susceptibility variants for a variety of diseases. One GWAS of inherited susceptibility to Acute Myeloid Leukemia (AML) has been conducted, but no EXWAS have been performed to measure risk of AML attributable to low-frequency constitutional genetic variation. We performed the first EXWAS of risk of AML as a nested case-control study in the DISCOVeRY-BMT (Determining the Influence of Susceptibility Conveying Variants Related to one-Year mortality after BMT) cohorts. The DISCOVeRY-BMT parent study examined transplant-related mortality in leukemia patients undergoing unrelated donor allogeneic BMT. To identify low frequency variants and genes contributing to increased susceptibility to AML we used genotype data from the Illumina HumanExome BeadChip typed in the DISCOVeRY-BMT cohorts; the HumanExome BeadChip contains 242,901 variants, which are mainly protein-coding variants. The optimal sequence kernel association test (SKAT-O) was used to analyze gene-level associations with risk of AML. These gene-based tests evaluate the cumulative effects of multiple single gene variants on risk of AML. Analyses were performed in all European American AML cases and two subtypes: 1) de novo AML, 2) de novo AML with normal cytogenetics. Models were adjusted for age at transplant and principal components to control for population stratification. For gene-based tests at least 2 variants with minor allele frequency (MAF) ≤ 5%, were required to be present in the gene. This yielded a total of 13,687 genes tested, and a Bonferroni corrected significance level of P<3.65 x 10-6. Association tests were performed in 1,189 AML cases reported to CIBMTR 2000-08 (Cohort 1) and 327 AML cases reported to CIBMTR from 2009-11 (Cohort 2). Controls in Cohorts 1 (n=1,986) and 2 (n= 515) were 10/10 HLA-matched unrelated donors who passed a comprehensive medical exam and deemed healthy. We used metaSKAT to combine Cohorts 1 and 2 and obtain p-values of association with AML. We present the results of gene-level tests significant in both cohorts. The likely pathogenicity of these variants was determined in silico using SIFT, PolyPhen and MutationTaster. Patient characteristics are in Table 1. DNMT3A, on chromosome 2, was associated in the gene-based test with risk of AML (Pmeta=1.70x10-9, Table 2). Three missense variants at MAF <1% comprise both overall AML and de novo AML gene-based association: exm177559 (Asn->Ser), exm177507 (Arg->His), and exm177543 (Arg->Trp). Normal cytogenetics de novo AML gene-based assocations consisted of only 2 of these variants: exm177559 and exm177507 (Table 2). While prevalence of exm177507 is <1% for all AML cases, in de novo AML with normal cytogenetics the MAF was higher at 3%. The other 2 variants had a MAF<1% irrespective of subtype. Somatically, DNMT3A is most frequently mutated in hematologic malignancies, with >30% of de novo AML cases with a normal karyotype and >10% of MDS patients having DNMT3A mutations. Although these are germline gene associations all three of the variants found have been reported somatically in hematologic malignancies. In 200 AML cases from The Cancer Genome Atlas (TCGA) p.R882H (represented as exm177507 on the exome chip) was a frequent somatic mutation (25%). Exm177543 (p.R635W) and exm177559 (p.N501S) are reported in the Catalogue of Somatic Mutations in Cancer (COSMIC) as somatic mutations involved in hematopoietic and lymphoid tissue in both cell lines and humans. Exm177507 and exm177543 show evidence of pathogenicity in all three in silico tools, while exm177559 was reported as deleterious and disease causing by Sift and MutationTaster, respectively. Our results show that multiple potentially pathogenic missense germline variants in DNMT3A comprise the gene-based association with AML, specifically de novo AML with normal cytogenetics. Given the functional nature of these variants it is possible germline risk stratification could be informative in determining AML risk, and subsequently development of AML harboring DNMT3A mutations. Confirmation of these findings in additional cohorts could have implications for individualized risk screening, prediction and prognosis. Additional cytogenetic subgroup analyses, including treatment-related AML, are underway. Disclosures Hahn: Novartis: Equity Ownership; NIH: Research Funding. McCarthy:Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; The Binding Site: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gamida Cell: Honoraria, Membership on an entity's Board of Directors or advisory committees. Sucheston-Campbell:NIH/NCI: Research Funding.

Abstract Background: Retinoblastoma (RB) is the most frequent pediatric retinal tumor. In the present study, to elucidate chemoresistance mechanisms and identify potential biomarkers in RB, we utilized RNA sequencing (RNAseq) technological platforms to reveal transcriptome profiles and identify any differentially expressed genes (DEGs) between an etoposide drug-resistant subline (Y79/EDR) and parental Y79 cells. Methods: To test whether Y79/EDR cells showed resistance to antineoplastic agents for RB, we treated the cells with etoposide, carboplatin and vincristine and analyzed them with a Cell Counting Kit-8 (CCK-8). Y79/EDR and parental Y79 cells were used for RNAseq and bioinformatics analysis to enable a genome-wide review of DEGs between the two lines using the DESeq R package (1.10.1). Then, DEG enrichment in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways was analyzed with KOBAS software. Next, real-time quantitative reverse transcription polymerase chain reaction (real time QRT-PCR) and cytotoxicity assays were performed to experimentally and functionally validate the identified candidate biomarkers. Results: Y79/EDR cells showed resistance to etoposide, carboplatin and vincristine at different concentrations. In total, 524 transcripts were differentially expressed in Y79/EDR cells based on analysis of fragments per kilobase of transcript per million fragments mapped (FPKM); among these, 57 genes were downregulated and 467 genes were upregulated in Y79/EDR cells compared to parental Y79 cells. We selected candidate DEGs, including ARHGAP9 , HIST1H4H , RELN , DDIT4 , HK2 , STC1 and PFKFB4, for mRNA expression validation with real time QRT-PCR assays and found that the expression levels determined by real time QRT-PCR were consistent with the RNAseq data. Further studies involving downregulation of ARHGAP9 with a specific siRNA showed that ARHGAP9 altered the cellular sensitivity of Y79 cells to etoposide and carboplatin. Conclusion: Our initial findings provided a genomic view of the transcription profiles of etoposide-induced acquired resistance in RB. Follow-up studies indicated that ARHGAP9 might be a chemoresistance biomarker in RB, providing insight into potential therapeutic targets for overcoming acquired chemoresistance in RB. These findings can aid in understanding and overcoming chemoresistance during treatment of RB in the clinic.

Abstract Abstract 3031 Background: Treatment-induced peripheral neuropathy (TIPN) can be a debilitating side-effect as well as a therapy-limiting complication in multiple myeloma (MM). Thalidomide (THAL) and bortezomib (BTZ) are two therapies frequently associated with TIPN in MM. Carfilzomib (CFZ) is a novel and highly selective epoxyketone proteasome inhibitor that differs from BTZ both structurally and mechanistically. CFZ overcomes BTZ-resistance in vitro, lacks the off-target activities of BTZ in preclinical studies, and does not cause neurotoxicity in long-term (6–9 month) chronic animal toxicology studies (Kirk et al. Blood, 2008). Single-agent CFZ produces durable responses in relapsed or refractory (R/R) MM without dose-limiting PN. Here we report on the clinical experience with single-agent CFZ in the Ph 2b PX-171-003-A1 trial in patients (pts) with R/R MM and Grade (G) 1/2 PN at study entry. Methods: Pts received CFZ at 20 mg/m2 IV, on Days 1, 2, 8, 9, 15, and 16 in a 28-day cycle (C) for the first C followed by 27 mg/m2 thereafter for up to 12 C. Pts completing 12 C were eligible to enter an extension study. Responses and progression were determined according to the International Myeloma Working Group (IMWG) criteria and were assessed by an Independent Review Committee (IRC). PN data were collected for all pts on study and included neuropathy history, neurological physical exam and PN-related quality of life data (FACT-GOG/NTx v 4.0 scores) collected at screening. Prospective neurological exams and subjective reporting of PN occurred every 2 cycles until study discontinuation to proactively assess for PN. Adverse event (AE) data were also collected, with AEs reported as ‘neuropathy peripheral', ‘neuropathic pain', ‘neuropathy', and ‘peripheral sensory neuropathy' included as PN. AE reports of ‘paraesthesias' and ‘dysesthesias' were counted separately. Results: Of the 266 pts with R/R MM in PX-171-003-A1, 237 (89%) had a history of PN which was attributable to prior anti-myeloma therapy, including THAL (108 pts/41%), BTZ (134 pts/50%), or both BTZ and THAL (17 pts/6.4%). 206 of the 266 (77%) had G1/2 PN at baseline and a median disease duration of 5.9 years. This subset with active PN at baseline had received a median of 5 prior lines of therapy (range 1–20), with a median 13 anti-myeloma agents, and a median of 2 prior BTZ- and 1 prior THAL- containing regimens. Prior therapies included 100% BTZ, and 100% either THAL (77%) or prior lenalidomide (95%). Responses in the subset of pts with baseline PN were nearly identical to those seen in the full study population with an overall response rate (ORR; ≥ partial response [PR]) of 24% and a clinical benefit response rate (CBR; ≥ minimal response [MR]) of 36%. The median duration of response (≥PR) was 7.4 mo (95% CI 5.6–not reached) and median duration of MR was 6.3 months in both the overall and PN-baseline cohorts. OS and TTP data will also be reported. The most common treatment-emergent ≥G3 adverse events regardless of relationship to study drug were primarily hematologic and were as follows: thrombocytopenia (24%), anemia (21%), lymphopenia (11%), pneumonia (9%), neutropenia (9%), fatigue (7%), hypercalcemia (7%), and hyponatremia (6%). Although 77% of pts had G1/2 PN at baseline, new onset PN was infrequent with PN AEs of any grade reported in 31 (15%) pts and G3 PN reported in only 1 (0.4%) pt. New onset or worsening of paraesthesias (6.8%) and dysesthesias (0%) was also infrequent. Conclusions: Analysis of the subset of pts (77%) with active PN (G1/2) in this single-agent Ph 2 trial of CFZ in pts with R/R MM demonstrated that PN has no impact on depth or durability of responses, or on the tolerability of CFZ, in heavily pretreated pts with multiply relapsed and refractory MM. Reports of new or worsening PN were very uncommon, and paraesthesias and dysesthesia were generally infrequent and mild. CFZ can be given to pts with baseline PN with little risk of exacerbation; prolonged therapy is possible in this population. Disclosures: Martin: Celgene: Honoraria; Onyx: Consultancy. Singhal:Celgene: Speakers Bureau; Takeda/Millenium: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Onyx: Research Funding. Vij:Onyx: Honoraria. Wang:Celgene: Research Funding; Onyx: Research Funding; Millenium: Research Funding; Novartis: Research Funding. Stewart:Millennium: Consultancy; Celgene: Honoraria. Jagannath:Millenium, OrthoBiotec, Celgene, Merck, Onyx: Honoraria; Imedex, Medicom World Wide, Optum Health Education, PER Group: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Lonial:Millennium: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Onyx: Consultancy, Research Funding. Jakubowiak:Millennium Pharmaceuticals, Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria; Centocor Ortho Biotech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Exelixis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Kukreti:Celgene: Honoraria; Roche: Honoraria; Ortho Biotech: Honoraria. Alsina:Millenium: Consultancy, Research Funding; Celgene: Research Funding; Novartis: Consultancy. Zonder:Millenium: Consultancy, Honoraria, Research Funding; Cephalon: Research Funding; Celgene: Honoraria. Wong:Onyx Pharmaceuticals: Employment. Vallone:Onyx Pharmaceuticals: Employment. Chang:Onyx Pharmaceuticals: Employment. Kauffman:Onyx Pharmaceuticals: Employment. Siegel:Millenium: Consultancy, Honoraria; Celgene: Consultancy, Honoraria.

Abstract Introduction: In multiple myeloma, randomized trials of maintenance therapy using thalidomide or lenalidomide following autologous transplant (ASCT) demonstrated prolonged progression-free survival (PFS), but overall survival benefit was inconsistent. The MY.10 trial (n=332) demonstrated improved PFS with thalidomide-prednisone maintenance therapy, but quality of life was inferior and overall survival was not improved. As a randomized trial with a no-treatment control arm and biospecimen collection, MY.10 provides a unique opportunity to identify predictors of benefit from therapy that could be used to personalize treatment. Immunomodulatory drug action is mediated in part through binding to cereblon (CRBN) and downregulation of IRF4. Candidate single nucleotide polymorphisms (SNPs) were selected from the CRBN/IRF4 pathway and other genes previously associated with myeloma prognosis, drug response and toxicity from literature review. The aim of this study was to investigate associations between candidate SNPs and benefit from immunomodulatory compound-based maintenance therapy, as well as prognostic impact. Methods: Genomic DNA was extracted from samples preserved in Trizol¨. SNPs were genotyped using TaqMan¨ genotyping assays on the ViiA7 qPCR platform. Analysis was performed on 187 patients with available samples and clinical data (86 in treatment arm; 101 in observation arm). Cox regression models were performed using SAS clinical 2.0 for prognostic impact of a single SNP on PFS, assessed with and without adjusted covariates (age, stage, performance status and response to ASCT). In treatment benefit analysis, PFS was modeled with genotype, treatment assignment and their interaction term. Results: SNPs with significant prognostic impact for PFS in all 187 patients were found in CRBN (rs1672753) (HR 0.59, 95%CI 0.4-0.86; p=0.006) and the following SNPs which had been found to be prognostic in prior studies were validated: CYP1A1 (rs1048943) (HR 1.98, 95%CI 1.19-3.27; p=0.008), CYP1B1 (rs1056836) (HR 0.72, 95%CI 0.52-0.99; p=0.043), and trend toward significance for SNP in CYP1A2 (rs2069514) (HR 2.02, 95%CI 0.98-4.15; p=0.057). Of these, only the CYP1A1 SNP was found to be possibly predictive of greater benefit from maintenance therapy. A SNP in ABCA1 (rs363717), previously associated with thalidomide-induced neuropathy,‎ was prognostic in this study (HR 1.44, 95%CI 1.03-2.02; p=0.033) but not predictive of treatment benefit. Table 1 lists SNPs associated with a differential level of benefit from maintenance therapy, including SNPs in FAM179a and ICAM1 that were possibly associated with harm from maintenance therapy. Table 1. SNPs and treatment interaction with significant impact on PFS. HR represent hazard ratio of treatment versus observation for a given genotype group. Asterisk Indicates trend toward significance. Wildtype Heterozygote & mutant p-value interaction Gene dbSNP ID SNP HR 95% CI HR 95% CI FAM179A rs1053667 T>C 0.46 0.33, 0.66 2.28 0.78, 6.65 0.003 ICAM1 rs1799969 G>A 0.51 0.36, 0.73 1.75 0.83, 3.70 0.007 CASP3 rs1049216 A>G 0.82 0.54, 1.25 0.41 0.25, 0.69 0.029 IRF4 rs12203592 C>T 0.69 0.47, 1.02 0.38 0.21, 0.69 0.062* CYP1A1 rs1048943 A>G 0.62 0.44, 0.87 0.11 0.02, 0.52 0.079* Conclusion: Previously identified SNPs in drug metabolism and drug efflux genes were validated to be prognostic in this cohort. The prognostic but not predictive significance of a SNP in CRBN suggests a possible role for CRBN in multiple myeloma disease biology independent of immunomodulatory therapy. SNPs predictive of differing degrees of benefit from immunomodulatory maintenance were found in genes involved in immunomodulatory activation, drug action and cell adhesion mediated drug resistance; SNPs in FAM179A and ICAM1 were possibly associated with harm from thalidomide maintenance and could potentially be used to identify patients unsuitable for immunomodulatory maintenance therapy. These results may be applicable to lenalidomide and pomalidomide, since immunomodulatory compounds exhibit similar chemical structures and mechanisms of action. Validation of these SNPs in prospective clinical trials involving other immunomodulatory can test this hypothesis. Further studies are needed to confirm our findings. Disclosures Off Label Use: thalidomide and prednisone maintenance for multiple myeloma. Bahlis:Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Amgen: Consultancy; Johnson & Johnson: Speakers Bureau; Johnson & Johnson: Consultancy; Johnson & Johnson: Research Funding. Song:Celgene Canada: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. White:Celgene Canada: Honoraria, Research Funding. Chen:Celgene: Consultancy, Honoraria, Research Funding. Seftel:Celgene: Honoraria, Research Funding. Howsen-Jan:Celgene: Honoraria, Research Funding. Reece:Amgen: Honoraria; Bristol-Myers Squibb: Research Funding; Merck: Research Funding; Novartis: Honoraria, Research Funding; Onyx: Consultancy; Millennium Takeda: Research Funding; Lundbeck: Honoraria; Otsuka: Research Funding; Janssen-Cilag: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Shepherd:Celgene: Honoraria, Research Funding. Chen:Celgene: Honoraria, Research Funding. Djurfeldt:Celgene: Research Funding. Reiman:Soricimed Biopharma Inc: Consultancy, Other: Scientific Advisory Board for Soricimed.

Abstract Introduction: Diffuse large B-cell lymphoma (DLBCL) is an aggressive non-Hodgkin’s lymphoma (NHL) comprising 3 molecular subtypes: germinal center B-cell (GCB), activated B-cell (ABC) and class III. ABC patients (pts) have a poor prognosis. The immunomodulatory drug lenalidomide (Len) produces durable responses in pts with aggressive NHL (Witzig 2011), with preferential activity reported in non-GCB DLBCL (Hernandez-Ilizaliturri 2011). Methods: This randomized, multicenter, open-label, phase 2/3 study was conducted to determine the efficacy and safety of single-agent Len vs single-agent investigator’s choice (IC) in relapsed/refractory DLBCL pts who received ≥2 prior therapies, or were ineligible for stem cell transplantation or further combination chemotherapy. DLBCL subtype (GCB vs non-GCB) was determined by a central pathology lab using immunohistochemistry (IHC) per the Hans method (Hans 2004). Pts were stratified by subtype, then randomized 1:1 to receive Len (25 mg/day, 21 days of 28-day cycle) or IC (gemcitabine, rituximab, etoposide, or oxaliplatin) until progressive disease (PD), unacceptable toxicity, or voluntary withdrawal. In the event of radiologically confirmed PD, pts in the IC arm were allowed to cross over to Len. The primary endpoint for Stage 1 was overall response rate (ORR), as determined by an Independent Response Assessment Committee. Progression-free survival (PFS), overall survival (OS) and subtype analysis using gene expression profiling (GEP) were exploratory endpoints. Concordance of GEP and IHC was evaluated from 3 separate laboratories. Results: IHC subtyping agreement rate among the 3 laboratories ranged from 87.5%-97.9%, and sensitivity of IHC to detect ABC or GCB subtypes vs GEP ranged from 92.3%-100.0%. By IHC, 102 DLBCL pts (GCB, n=48; non-GCB, n=54) were treated with ≥1 dose of Len or IC (modified intent-to-treat population) in Stage 1. In this heavily pretreated population, >90.0% of pts received ≥2 prior systemic chemotherapies; 25 pts in Len and 32 pts in IC received ≥3 prior systemic chemotherapy regimens. Median age was 65 y in the IC arm vs 69 y in the Len arm. Twenty-nine pts crossed over from IC to Len after confirmed PD. All pts, regardless of subtype or therapy group, experienced ≥1 treatment-emergent adverse event, with neutropenia, anemia, and thrombocytopenia being the most common. Efficacy data are presented in the Table. Pts with GCB or non-GCB DLBCL (per IHC) treated with Len had similar ORR, but the data suggested greater improvements in PFS and OS with Len vs IC in the non-GCB pts. In an exploratory analysis of pts subtyped by GEP, ABC pts treated with Len vs IC-treated showed greater improvements in ORR, PFS, and OS compared with GCB pts. Prespecified criterion to advance to Stage 2 was a 2-sided 15% significance level in ORR in favor of Len based on IHC-defined subtype. The data did not fulfill this requirement, and Stage 2 was not opened. Conclusion: Len monotherapy showed clinical activity in heavily pretreated pts with DLBCL. The data suggest improved ORR, PFS, and OS with Len vs IC in the non-GCB population as defined by IHC, and the difference appears to be more pronounced in the ABC population as defined by GEP. Subtyping by GEP is warranted in further studies of Len in DLBCL. Abstract 628. Table 1.Table. Efficacy DataBy IHCBy GEPOverallGCBNon-GCBGCBABCLen(n=51)IC(n=51)Len(n=23)IC(n=25)Len(n=28)IC(n=26)Len(n=14)IC(n=16)Len(n=11)IC(n=16)ORR, % (95% CI)27.5 (15.9-41.7)11.8 (4.4-23.9) 26.1 (10.2-48.4)12.0 (2.5-31.2)28.6 (13.2-48.7)11.5 (2.4-30.2)21.4 (4.7-50.8)12.5 (1.6-38.3)45.5 (16.7-76.6)18.8 (4.0-45.6)P Value .079 .279 .179 .642 .206PFS, med wk (95% CI)13.6 (8.6-17.7)7.9 (6.3-9.0) 10.1 (8.3-22.3)29.0 (6.3-20.6)15.1 (8.3-24.1)7.1 (5.3-8.4)13.2 (8.3-24.9)7.1 (6.0-20.6)82.0 (7.3-NA)6.2 (4.3-10.1)P Value .041 .550 .021 .506 .105HR (95% CI) 0.64 (0.41-0.99) 0.82 (0.43-1.57) 0.50 (0.27-0.92) 0.77 (0.35-1.68) 0.44 (0.15-1.23)OS, med wk (95% CI)31.0 (16.6-41.3)24.6 (12.7-33.9) 30.0 (14.9-44.4)24.9 (13.7-58.3)32.3 (15.9-48.1)20.4 (10.3-33.9)30.0 (18.0-34.6)20.1 (13.7-36.9)108.4 (9.6-108.4)18.6 (6.6-48.0)P Value .673 .526 .253 .767 .144HR (95% CI) 0.91 (0.59-1.41) 1.23 (0.65-2.34) 0.70 (0.38-1.30) 1.12 (0.52-2.42) 0.47 (0.17-1.33) Abbreviations: CI, confidence interval; HR, hazard ratio; med, median; NA, not applicable/not available. Disclosures Czuczman: Celgene: Consultancy. Off Label Use: This abstract describes a clinical trial of lenalidomide, which is an orally-available immunomodulatory agent under investigation for treating patients with diffuse large B-cell lymphoma.. Davies:GlaxoSmithKlein: Research Funding; Hoffman La Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding. Wagner-Johnston:Celgene: Research Funding. Gascoyne:Celgene: Consultancy, Research Funding. Salles:Pfizer: Honoraria; Gilead: Honoraria; Jansen: Honoraria; Hoffman La Roche: Honoraria; Celgene: Honoraria; Mundipharma: Honoraria. Witzig:Celgene Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding. Zinzani:Mundipharma: Honoraria; Pfizer: Honoraria; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria; Millennium Takeda: Honoraria; Celgene: Honoraria; Teva: Membership on an entity's Board of Directors or advisory committees. Wright:Celgene: Research Funding. Staudt:Celgene Corporation: Research Funding. Repici:Celgene: Employment. Song:Celgene: Employment. Manzke:Celgene: Employment.