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Abstract We have recently reported that event-free survival at 24 months from diagnosis (EFS24) is a robust endpoint for assessment of disease related outcome for newly diagnosed patients with diffuse large B-cell lymphoma (DLBCL) treated with anthracycline-based immunochemotherapy (IC). Patients who achieve EFS24 following IC have a subsequent overall survival that is equivalent to the age and sex matched general population. The IPI was developed in the pre-rituximab era using OS/EFS endpoints. While the IPI is associated with outcome in the IC era, the original survival estimates for the IPI risk groups are outdated. The IPI is also a discrete risk classifier, with only 6 possible groups. Here we remodel the IPI using EFS24 as the endpoint in a large international cohort of patients treated with IC. This model provides an individual level 0-100% risk of failing to achieve EFS24 for each patient and can be used for patient prognosis, treatment stratification, and risk assessment. Methods Newly diagnosed DLBCL patients treated with immunochemotherapy from the University of Iowa/Mayo Clinic SPORE Molecular Epidemiology Resource, NCCTG N0489 clinical trial, GELA LNH2003B program, and a Lyon, France based hospital registry were included in the original EFS24 study. Patients with a relapse, progression, unplanned re-treatment, or death due to any cause within 730 days of diagnosis were considered a failure for the EFS24 endpoint. Patients alive and progression/relapse free at 730 days from diagnosis with no subsequent treatment following initial IC were considered a success for the EFS24 endpoint. Variables selected for potential model inclusion were the IPI components (age, stage, ECOG PS, number of extranodal sites, and LDH), as well as standard clinical variables typically reported in studies of DLBCL: presence of B-symptoms, bone marrow involvement, bulky disease (>10 cm), and sex. The IPI24, a prognostic model for EFS24, was developed using logistic regression models. Model building began by fitting the classic IPI score (0-5), then allowing individual IPI variables to carry different model weights and number of categories, followed by dropping insignificant variables, finally adding any additional significant variables. Model performance was assessed using bias corrected c-statistics, AIC, and R2 values. Model selection was done using the complete case set with multiple imputation on the full dataset used to refine parameter estimates for the final model. Results 1596 total patients were available for modeling. The median age was 62 (range 18-93) and 53% were male; 33% were IPI 0-1, 25% were IPI 2, 25% were IPI 3, and 17% were IPI of 4-5. The failure rate for achieving EFS24 was 29%. All variables but sex (p=0.33) were univariately associated with EFS24 (p<6.4x10-5). The original IPI had good prognostic ability for EFS24 (c=0.696, p=2.2x10-32). Allowing multiple categories for ECOG PS, stage, and age (continuous) improved model fit and prognostic ability (c=0.727). The number of extranodal sites was not significant when IPI variables were modeled separately and was removed from the model. Sex and bulky disease were additional significant variables when added to the model. Thus, the final IPI24 model contained the following risk predictors: male sex, ECOG PS (0 vs. 1 vs 2 vs 3-4), stage (I vs. II, vs. III vs. IV), LDH (elevated vs. normal range), bulky disease > 10cm, and age (continuous). This model resulted in improved fit and prognostic ability (c=0.749) over the standard IPI (c=0.696, bootstrap p<0.001). Model validation was performed on an additional 158 patients from the SPORE MER and showed good concordance (c=0.697). Additional validation is planned in a larger set of independent patients. Conclusion The IPI24, generated using standard clinical variables, yields an individual risk prediction for failing to achieve EFS24 following IC for treatment of DLBCL. The IPI24 has superior prognostic ability to the standard IPI and can be implemented in the clinic using a nomogram or as a simple electronic application. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 3949 Acute kidney injury (AKI) is a common but serious sequela of multiple myeloma. Recently, the International Myeloma Working Group (IMWG) introduced a new renal response criteria with complete (CRenal), partial (PRenal) and minimal (MRenal) responses. This study compares the IMWG criteria with other models to determine their correlation with overall survival (OS). Patients with multiple myeloma and AKI were identified from centers around the world. OS was calculated from the day of AKI. Renal function was assessed by estimated glomerular filtration rate (eGFR) via MDRD method. Hematologic response was the best achieved as assessed by International Uniform Response Criteria for Multiple Myeloma. Only patients with peak serum creatinine (Scr) ≥ 2.0 mg/dl were included. Separate analyses were performed on the newly diagnosed (ND) versus previously treated (PT) patients. A total of 158 patients were collected from centers in United States, United Kingdom, France and Austria. Fourteen patients were excluded for having peak Scr < 2.0 mg/dl and one for repeated episodes of AKI. Median age of the 143 patients was 64 (34 – 87) years, 58.7% were male and 115 were newly diagnosed. Median Scr was 5.1 (2.0 to 18.6) mg/dl and median eGFR was 10.6 (2.8 – 36.5) ml/min/1.72 m2. Dialysis was required in 49.3%, and 72.9% were dialysis independent at the end of the study. By IMWG criteria, median OS ranged between 6.0 months (m) in PT patients with no renal response (NRenal) to 23.7m in patients with CRenal, p = 0.34 (Table 1). In ND patients, OS was 31.4m in NRenal vs 73.8m in CRenal (p = 0.08). However, OS was similar between PRenal and CRenal, p = 0.70 (Figure 1). If only patients with a hematologic PR or better were analyzed, the OS range was 6.0m in NRenal to 23.7m in CRenal in PT patients (p = 0.85) and 36.6m in NRenal to 73.8m in CRenal in ND patients, p = 0.73.Table 1.Previously TreatedNMedian SurvivalNMedian Survival (>PR) CRenal323.7 m323.7 m PRenal413.1 m312.8 m MRenal512.0 m119.2 m NRenal166.0 m56.0 m p-value0.340.85Newly Diagnosed CRenal2273.8 m2273.8 m PRenal27Not Reached23Not Reached MRenal2265.6 m1965.6 m NRenal4331.4 m2136.6 m p-value0.080.73Figure 1.Overall survival (OS) of 115 patients evaluated by the IMWG renal response criteria. OS was not significantly different by Log-Rank test between patients with CRenal and NRenal, p = 0.08.Figure 1. Overall survival (OS) of 115 patients evaluated by the IMWG renal response criteria. OS was not significantly different by Log-Rank test between patients with CRenal and NRenal, p = 0.08. The best model tested was one that defined renal response (RR) as regaining or maintaining dialysis independence and no response (NR) as dialysis dependence. RR was associated with a superior survival for both PT patients (13.5 m vs 6.0m (NR), p = 0.03) and ND patients (73.8m vs 20.1m (NR), p < 0.001). RR increased with the depth of hematologic response, p = 0.04. RR occurred in 75% of the PT patients with hematologic PR or better and 66.7% in those with less than PR, p = 0.64. In ND patients, RR occurred in 85.7% of those with PR or better and 54.6% of those with PR or less, p = 0.003. This may explain the differences in OS when hematologic response was considered. In PT patients with hematologic PR or better, renal response did not improve OS (21m vs 6m, p = 0.28) but it remained beneficial in the ND patients (73.8m vs 35.1m, p = 0.04, Figure 2). Renal response was not significantly associated with OS for any patient with hematologic response that was VGPR or better. In a multivariate analysis, RR (p = 0.001), ND (p <0.001) and PR or better hematologic response (p = 0.046) were associated with OS.Figure 2.In a separate model, 83 newly diagnosed patients with hematologic response of PR or better were evaluated. Patients who were dialysis independent achieved a renal response (RR) and those who remained on dialysis had no response (NR). Patients with RR had a superior overall survival than patients with NR. Renal response was independent of a hematologic response of PR or better.Figure 2. In a separate model, 83 newly diagnosed patients with hematologic response of PR or better were evaluated. Patients who were dialysis independent achieved a renal response (RR) and those who remained on dialysis had no response (NR). Patients with RR had a superior overall survival than patients with NR. Renal response was independent of a hematologic response of PR or better. The results of our study suggest renal response is important to OS but the depth of response was not as important. Renal response was most important when the hematologic response was less than a VGPR. This supports renal response as part of the overall response assessment in multiple myeloma patients. Based on our results, reducing the number of response categories and simplifying the current consensus criteria seems justified. Median survival of the 143 patients evaluated by the IMWG renal response criteria. Overall survival was calculated by Kaplan Meier method. Differences in survival were evaluated by Log-Rank test. Disclosures: Ludwig: Mundipharma, Janssen-Cilag: Research Funding, Speakers Bureau. Hutchison:The Binding Site: Honoraria.

Abstract Abstract 4013 Background: In recent years, azacytidine (AZA) has become the standard of treatment for high risk myelodysplasia (MDS). The approved schedule of AZA uses a 75mg/m2/d s.c. regimen for 7 days based on the CALGB-9221 (Silverman, JCO 2002) and the AZA-001 studies (Fenaux, Lancet Oncol 2009). The clinical response rates after AZA have been extensively presented but there is only limited data on the rates of cytogenetic response (CyR). Based on the review of the literature, there are no specific cytogenetic data published on prospective trials. Methods: We based our analysis on a randomized phase 2 study from the US Leukemia Intergroup (E1905 study, NCT00313586) testing 10 days of AZA (50mg/m2/d s.c.) vs 10 days of AZA+ the histone deacetylase inhibitor entinostat (4 mg/m2/d PO days 3 and day 10). MDS, CMML, and AML with myelodysplasia-related changes were included. This analysis includes all patients with cytogenetic abnormalities (at baseline or acquired following treatment) with available cytogenetic follow-up (cycle 6). Of 150 patients, 70 demonstrated baseline cytogenetic abnormalities. To date, forty patients (27 MDS and 13 AML) were evaluable for both time points. Karyotypes were performed at local laboratories, and reviewed centrally (RPK and GH). Cytogenetic response was assessed using IWG 2000 (Cheson et al, Blood 2000) criteria. Results: The clinical response rate (CR+PR+ trilineage HI) according to IPSS cytogenetic risk stratification were of 20%, 33%, and 35% for favorable, intermediate and poor cytogenetic risk groups respectively (p=NS). Patients with Chr 7 abnormalities (i.e. -7 or -7q, n=18) had a response rate of 28% including 17% CR. Of patients with complete cytogenetic data, the rate of overall CyR was 52% (n=21): 22% (n=9) complete CyR, 30% (n=12) partial CyR. This represents a complete CyR of 13% and a partial CyR of 23% as a proportion of all treated patients with initial cytogenetic abnormalities (including those who did not receive six cycles of therapy). To date, confirmatory FISH analyses were available for 4 patients with CyR (2 CCyR and 2 PCyR). All four had complete clearance of their cytogenetic clone. Among the cytogenetic responders, 15 had MDS and 6 had AML (p=NS). CyR did not differ between the two treatment arms. CyR and clinical response were highly correlated (p<0.001): all patients with complete CyR and 7/10 partial CyR had a clinical CR. Only 3 patients (1 CCyR and 2 PCyR) had a CyR without associated clinical response. Among 8 patients with cytogenetic progression, 3 pts showed increased frequency of a known aberration and 5 showed new or additional aberration including 2 cases involving Chr7. 65 AZA-treated patients from AZA001 had comparable cytogenetic results available. Only 3 patients experienced complete CyR 4.6% with 33.8% partial CyR (n=22). In contrast, the reported rate of clinical response was similar in the two studies. Complete CyR were more frequent in the E1905 10 days AZA schedule compared to the 7 days AZA schedule (p=0.007). There was no difference in overall CyR between the two studies. Conclusions: Both the standard AZA schedule and the 10 day schedule administered on E1905 lead to high rates of cytogenetic response. The novel schedule explored in E1905 demonstrated a particularly high rate of complete CyR (22%) with complete clearance of abnormal clone by FISH in 4 tested patients. Further prospective comparison of different AZA schedules will be needed to confirm this higher rate of complete CyR and determine its clinical significance. Disclosures: Beach: Celgene: Employment. Gore:Celgene: Consultancy, Research Funding, stock options; Syndax: Consultancy.

Abstract Introduction: Nivolumab (nivo) is a fully human IgG4 monoclonal antibody (mAb) targeting programmed death receptor-1 (PD-1). Nivo has demonstrated clinical activity and an acceptable safety profile in a phase 1b study (NCT01592370; CheckMate 039) in patients (pts) with relapsed/refractory hematologic malignancies. In pts diagnosed with Hodgkin lymphoma (HL), after a median 86 weeks of follow-up, 7/20 responders maintained a response for >1.5 years (Ansell S et al. Blood 2015;126:583), and after a median follow-up of 67 weeks, clinical activity (investigator-assessed objective response rate) was demonstrated in follicular lymphoma (FL; 40%), diffuse large B-cell lymphoma (DLBCL; 36%), mycosis fungoides (15%), and peripheral T-cell lymphoma (PTCL; 40%) (Lesokhin AM et al. J Clin Oncol 2016;34:2698). CheckMate 039 also included a cohort of pts who had received nivo in combination with ipilimumab (ipi), a fully human mAb targeting cytotoxic T-lymphocyte antigen 4 (CTLA-4). Combination of CTLA-4 and PD-1 blockade has shown superior efficacy compared with nivo or ipi alone in preclinical studies and solid tumor malignancies (Wolchok JD et al. N Engl J Med 2013;369:122; Larkin JM et al. N Engl J Med 2015;373:22; Antonia SJ et al. Lancet Oncol 2016;17:883). The aim of this cohort study was to evaluate the safety and efficacy of combined immune checkpoint blockade (nivo+ipi) in pts with the following hematologic malignancies: HL, B-cell non-Hodgkin lymphoma (B-NHL; FL and DLBCL), T-cell NHL (T-NHL; cutaneous T-cell lymphoma [CTCL] and PTCL]), and multiple myeloma (MM). Methods: Nivo+ipi were given at 3 mg/kg IV and 1 mg/kg IV, respectively, every 3 weeks for 4 doses, followed by nivo monotherapy (3 mg/kg) every 2 weeks for up to 2 years. Pts with any of the above histologies, relapsed or refractory disease after ≥2 prior lines of therapy, and adequate organ function were included in the study. Prior systemic therapy may have included chemotherapy and autologous hematopoietic stem cell transplantation (auto-HSCT). Prior anti-PD-1 therapy and allogeneic (allo)-HSCT were not permitted. The primary endpoint was safety. Secondary endpoints included investigator-assessed objective response rate (ORR), best overall response, duration of response (DOR), and progression-free survival (PFS). Results: In total, 65 pts were treated with nivo+ipi (31 HL, 15 B-NHL, 11 T-NHL, 7 MM, and 1 with primary mediastinal B-cell lymphoma [PMBL] who was included in the overall safety cohort only). Median (range) number of prior systemic therapies was 4 (2, 10; HL), 3, (1, 16; B-NHL), 4 (1, 11; T-NHL), and 5 (2, 20; MM). Among patients with HL, only 13% (4/31) had prior auto-HSCT. 2 pts with HL and 1 with T-NHL proceeded to allo-HSCT after stopping study therapy. Across all cohorts, median follow-up was 11.4 months. 5 pts (8%) discontinued due to a drug-related adverse event (AE). The most common drug-related AEs of any grade were fatigue (17 pts [26%]), pyrexia (15 [23%]), and diarrhea (12 [18%]). 19 pts (29%) had a drug-related AE of grade ≥3. 31 pts (48%) had a serious AE. 24 pts (37%) died: HL 2 pts, B-NHL 11, T-NHL 6, MM 4, PMBL 1. Among those pts, 22 (34%) were from disease progression (HL 2 pts, B-NHL 10, T-NHL 5, MM 4, PMBL 1); no deaths were due to an AE. Clinical outcome data are presented (Table). Conclusions: These are the first reported data of combination checkpoint blockade therapy in hematologic malignancies. Overall, the combination of nivo+ipi in these heavily pretreated patients demonstrated a safety and efficacy profile similar to that previously reported for nivo monotherapy in HL, NHL, and MM. Additional follow-up may further clarify the role of ipi in this cohort of patients. In this predominantly transplant-naïve group of patients with HL, the efficacy of nivo+ipi was similar to that seen in patients with relapsed/refractory HL treated with nivo alone. Funding: Bristol-Myers Squibb (BMS). Medical writing: S Addison, Caudex, funded by BMS Disclosures Ansell: BMS, Seattle Genetics, Merck, Celldex and Affimed: Research Funding. Gutierrez:Bayer Health Care Pharmaceuticals, Inc.: Other: Traveling and Lodging- Food and Beverage; E.R. Squibb & Sons, LLC (Bristol Myers Squibb): Consultancy, Other: Travel and Lodging; Incyte Corporation: Consultancy; Pfizer Inc: Consultancy; Merck Sharp & Dohme Corporation: Consultancy, Other: Travel and Lodging; Pharmacyclics LLC, An AbbVie Company: Other: Food and Beverage. Shipp:Cell Signaling: Honoraria; Bristol-Myers Squibb: Consultancy, Research Funding; Bayer: Research Funding; Merck, Gilead, Takeda: Other: Scientific Advisory Board. Moskowitz:Seattle Genetics: Research Funding; Seattle Genetics, Merck: Consultancy. Borello:Bristol-Myers Squibb: Research Funding, Speakers Bureau. Popa-Mckiver:Bristol-Myers Squibb: Employment, Equity Ownership. Farsaci:Bristol-Myers Squibb: Employment. Zhu:Bristol-Myers Squibb: Employment. Armand:Sequenta Inc: Research Funding; Pfizer: Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Infinity Pharmaceuticals: Consultancy; Roche: Research Funding; Merck: Consultancy, Research Funding.

Abstract Abstract 1881 Background: Drug-disease modeling and simulation has recently been proposed to support drug development decisions in patients with liquid and solid tumors (Claret et al J Clin Oncol, 27:4103-4108, 2010; Wang et al. Clin Pharmacol Ther, 86:167-174, 2009). We hypothesized that similar modeling based on a decrease in M-protein may be applied in multiple myeloma. The objective was to use a modeling and simulation approach to leverage available lenalidomide multiple myeloma data and support pomalidomide development decisions by, 1) developing a drug-independent link between tumor burden reduction (as assessed by change from baseline in serum M-Protein) and survival and PFS and 2) simulating expected survival and PFS based on interim M-protein data of the phase 1/2 trial (CC-4047-MM02, NCT00833833) of pomalidomide (POM) in patients with relapsed and refractory multiple myeloma who have received at least 2 prior therapies including lenalidomide (LEN) and bortezomib. Methods: M-Protein measurements were modeled as a function of time from 704 patients included in two phase 3 clinical studies of LEN plus dexamethasone (DEX) vs. DEX (MM010, Dimopoulos, NEJM 357, 2123–2132, 2007 and MM009, Weber, NEJM 357, 2133–2142, 2007). Models were developed for survival and PFS times as a function of change in M-protein level at end-of-cycle 2 (week 8) from baseline as well as other prognostic factors. Interim M-protein data from the ongoing MM-002 POM study (217 patients) were modeled to simulate clinical endpoints. Results: Based on lenalidomide Phase 3 data, week-8 change in M-Protein (p < 0.00001), ECOG performance status (p < 0.0009), baseline albumin, hemoglobin and creatinine levels (p < 0.01) were significant independent predictors of survival when week-8 change in M-Protein (p < 0.00001) and baseline hemoglobin (p < 0.001) were significant independent predictors of PFS. Observed survival and PFS distributions over 100 weeks in lenalidomide studies and difference between the two treatments (LEN + DEX vs. DEX) were consistent with the 95% confidence intervals (CI) of the models. Model predictions (95% PIs) of median survival and PFS based on week-8 change in M-Protein following treatment with POM and POM + DEX are presented in the table below. The recently disclosed observed medians and 95% CIs for all endpoints and all arms from MM-002 are included in the model. Conclusions: Change in M-protein level as a continuous longitudinal biomarker appears to be a potential indicator to assess drug effect in multiple myeloma studies using modeling and simulation based on early interim data. PFS predicted by the model and the actual PFS are similar and thus may support end-of-Phase 2 decision (Bruno et al Clin Pharmacol Ther 86:136-138, 2009). Current simulations indicate encouraging results for POM in a refractory multiple myeloma patient population who have received prior treatment that includes lenalidomide and bortezomib but these exploratory methods require confirmation as part of ongoing studies. Disclosures: Bruno: Pharsight: Employment; Celgene Corporation: Research Funding. Off Label Use: Pomalidomide is not an FDA licensed product for multiple myeloma treatment. Jonsson:Pharsight: Employment; Celgene Corporation: Research Funding. Zaki:Celgene Corporation: Employment. Jacques:Celgene Corporation: Employment. Swern:Celgene Corporation: Employment. Richardson:Millennium Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Johnson & Johnson: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees. Claret:Celgene Corporation: Consultancy, Research Funding; Pharsight: Employment.

Abstract Abstract 4112 We report the characterization of BMS-911543, a potent and functionally selective small molecule inhibitor of the Janus kinase family (JAK) member, JAK2. BMS-911543 is a reversible inhibitor of JAK2 with a biochemical IC50 of 0.001 μ M and Ki of 0.48 nM. It has over 74- and 350-fold selectivity against the other JAK family members, JAK3 and JAK1, respectively. Further, examination of > 450 other kinases did not reveal significant inhibitory activity for this JAK2 inhibitor. Functionally, BMS-911543 displayed potent anti-proliferative and pharmacodynamic (PD) effects in mutated JAK2-expressing cell lines dependent upon JAK2-STAT signaling and had little activity in cell types dependent upon other pathways such as JAK1 and JAK3. BMS-911543 was evaluated in colony growth assays using primary progenitor cells isolated from patients with JAK2V617F-positive myeloproliferative disease (MPD) and resulted in an increased anti-proliferative response in MPD cells as compared with those from healthy volunteers. Similar to these in vitro observations, BMS-911543 was also highly active in in vivo models of JAK2-pSTAT signaling in multiple species (mouse, rat, dog and monkey) with sustained pathway suppression being observed after a single oral dose. Additionally, BMS-911543 was evaluated for effects in a JAK2V617F-expressing SET-2 xenograft model system and displayed a minimally effective dose of <2 mg/kg on pSTAT5 pathway suppression, which lasted up to 8 hours. BMS-911543 was also compared to pan-JAK inhibitors in a mouse model of immunosuppression. At low dose levels active in JAK2-dependent PD models, no effects were observed on antigen-induced IgG and IgM production whereas a pan-JAK family inhibitor showed pronounced effects at all dose levels tested. The mechanistic selectivity of BMS-911543 to pan-JAK family inhibitors was extended through comparative analysis of these inhibitors in whole genome gene expression profiling experiments performed in sensitive cell types. In this comparison, BMS-911543 modulated a distinct subset of transcriptional changes as compared to pan-JAK inhibitors, thereby defining a minimal set of transcriptional changes underlying the pharmacologic effects of JAK2 inhibition. Collectively these results define the mechanistic basis for a differential therapeutic index between selective JAK2 and pan-JAK family inhibition pre-clinically and suggest a therapeutic rationale for the further characterization of BMS-911543 in patients with MPD and in other disorders characterized by constitutively active JAK2 signaling. Disclosures: Purandare: Bristol-Myers Squibb: Employment. McDevitt:Bristol-Myers Squibb: Employment. Gottardis:Bristol-Myers Squibb: Employment. You:Bristol-Myers Squibb: Employment. Lombardo:Bristol_Myers Squibb: Employment. Penhallow:Bristol-Myers Squibb: Employment. Vuppugalla:Bristol-Myers Squibb: Employment. Trainor:Bristol-Myers Squibb: Employment. Lorenzi:Bristol-Myers Squibb: Employment.

Abstract Classical Hodgkin lymphomas (cHLs) include infrequent malignant Hodgkin Reed-Sternberg (HRS) cells within an extensive but ineffective inflammatory/immune cell infiltrate. HRS cells exhibit frequent copy number alterations (CNAs) of 9p24.1/CD274 (PD-L1)/PDCD1LG2(PD-L2), ranging from low-level polysomy to relative copy gain and high-level amplification, all associated with increased expression of programmed death receptor-1 (PD-1) ligands on the tumor cell. PD-1 ligands engage the PD-1 receptor on T cells, inhibiting T cell activation and anti-tumor immune responses. cHL patients (pts) with the highest-level 9p24.1 alterations, PD-L1/PD-L2 amplification, have inferior progression-free survival (PFS) after standard primary chemotherapy (Roemer et al. J Clin Oncol 2016). Given the demonstrated responsiveness of cHL to PD-1 blockade, we examined the prevalence and type of 9p24.1 genetic alterations, PD-L1 expression, and association of these alterations with clinical outcome in pts receiving nivolumab (nivo; anti-PD-1) for relapsed/refractory (R/R) cHL. CheckMate205 is a multicenter, multicohort, phase 2 trial of nivo in R/R cHL. This analysis focused on 2 cohorts: pts with recurrent cHL following autologous stem cell transplantation (ASCT) and subsequent brentuximab vedotin (BV) (cohort B), and pts with R/R cHL following ASCT and BV given pre- or post-ASCT (cohort C). Pts received nivo 3 mg/kg every 2 weeks. Best overall response (BOR) and PFS were assessed by an independent radiological review committee (IRRC). In pts with available tumor biopsies, 9p24.1 genetic alterations were evaluated via fluorescence in situ hybridization (FISH) assay; probes encompassed CD274 (PD-L1, red) or PDCD1LG2 (PD-L2, green)and included a centromeric control (aqua).Dual immunohistochemical staining of PD-L1/PAX5 was performed to delineate PD-L1 expression in PAX5dim+ HRS cells and PAX5- cells in the tumor microenvironment. A modified PD-L1 H-score (range 0-300) was calculated by multiplying the percentage of PAX5+ (malignant) or PAX5- (non-malignant) cells with positive staining (0-100%) and the average intensity of positive staining (1-3+; ≥50 RS cells counted). All p-values are nominal. 96 pts had evaluable baseline tumor biopsy specimens; all 96 had detectable 9p24.1 alterations: polysomy in 10/96 (10%), copy gain in 56/96 (58%), amplification in 28/96 (29%), and presumptive rearrangement (split-apart FISH signal) in 2/96 (2%) (Figure). There was a significant association between PD-L1 protein expression (H-score) and the level of 9p24.1 alterations in HRS cells (p=0.002) (Figure). We next evaluated the association between BOR and defined 9p24.1 alterations and PD-L1 H-scores. The level of 9p24.1 CNAs was significantly associated with BOR (p=0.01); no pts with progressive disease (PD) had genomic amplification and no pts with complete response (CR) had polysomy. Similarly, there was significant association between PD-L1 H-score in HRS cells and BOR (p=0.02); all pts with PD had PD-L1 H-scores in quartiles (Q) 1/2, whereas most pts with CR had PD-L1 H-scores in Q4. We also assessed the association of PFS with 9p24.1 status and PD-L1 H-scores. The level of 9p24.1 alterations was associated with PFS; pts with 9p24.1 amplification had the most favorable PFS with nivo. HRS cell PD-L1 H-score (by quartiles) was also significantly associated with PFS (p=0.048), as pts with PD-L1 H-scores in Q1/Q2 had significantly shorter PFS than those with scores in Q3/Q4 (p=0.01). In contrast, there was no association between PD-L1 expression on non-malignant cells in the tumor microenvironment and PFS (p=0.43). In conclusion, all evaluable pts in this study had genetic alterations of 9p24.1/PD-L1/PD-L2 and copy number-dependent increased expression of PD-L1 in HRS cells. Although high-level alterations of 9p24.1 and increased PD-L1 expression were previously linked with inferior response to standard primary chemotherapy, we now associate these parameters with more favorable outcomes to targeted PD-1 blockade. These analyses also highlight the importance of quantifying and delineating PD-L1 expression in HRS cells and non-malignant cells in the tumor microenvironment in cHL biopsy evaluation. While further research is needed to guide possible use in clinical practice, these data advance understanding of 9p24.1 alterations and PD-L1 expression as prognostic biomarkers in cHL. Disclosures Engert: Takeda, BMS: Consultancy, Honoraria, Research Funding. Zinzani:Abbvie: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; MorphoSys: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Celegene: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Timmerman:Bristol-Myers Squibb, Kite Pharma, Valor Biopharmaceuticals, Janssen: Research Funding; Seattle Genetics, Genmab, Celgene: Consultancy, Honoraria. Ansell:BMS, Seattle Genetics, Merck, Celldex and Affimed: Research Funding. Armand:Bristol-Myers Squibb: Consultancy, Research Funding; Pfizer: Research Funding; Sequenta Inc: Research Funding; Roche: Research Funding; Merck: Consultancy, Research Funding; Infinity Pharmaceuticals: Consultancy. Kuruvilla:BMS: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Amgen: Honoraria; Celgene: Consultancy, Honoraria; Merck: Honoraria; Roche Canada: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Lundbeck: Honoraria. Cohen:Bristol-Myers Squibb: Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium/Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Infinity: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Collins:Takeda: Consultancy, Honoraria, Speakers Bureau. Trneny:Roche, Celgene, Takeda, Janssen, Gilead, Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche, Celgene: Research Funding. Farsaci:Bristol-Myers Squibb: Employment. Kato:Bristol-Myers Squibb: Employment. Sumbul:Bristol-Myers Squibb: Employment. Rodig:Bristol-Myers Squibb: Honoraria, Research Funding; Perkin Elmer: Membership on an entity's Board of Directors or advisory committees. Shipp:Bayer: Research Funding; Merck, Gilead, Takeda: Other: Scientific Advisory Board; Cell Signaling: Honoraria; Bristol-Myers Squibb: Consultancy, Research Funding.

Abstract Background: We previously reported that Lenalidomide combined with R-CHOP (R2CHOP) has significant activity in non-GCB (non-germinal center B-cell) subtype of DLBCL as defined by immunohistochemistry (IHC) using Hans algorithm (J Clin Oncol. 2015 Jan 20;33(3):251-7). However, defining non-GCB subtype of DLBCL by IHC as opposed to the "gold standard" gene expression profiling (GEP) is subject to technical limitations and its prognostic value has not reproduced in some recently published studies. In addition, recent reports questioned prognostic value of GEP in prospective clinical trials as opposed to initial reports from retrospective case series. To address these concerns, we assessed outcomes by cell of origin (COO) as determined via GEP using NanoString Lymphoma Subtyping Test (LST) on formalin-fixed paraffin-embedded (FFPE) tissue on patients enrolled in a phase 2 study of R2CHOP and an independent comparison cohort of patients treated with RCHOP alone. Methods: Eligible patients for R2CHOP phase 2 study MC078E were adults with newly diagnosed, untreated, stages II-IV CD20 positive DLBCL. Patients received oral lenalidomide 25 mg days 1-10 with standard dose R-CHOP every 21 days for 6 cycles. All patients received pegfilgrastim on day 2 of each cycle and aspirin prophylaxis. DLBCL molecular subtype was determined by GEP using NanoString LST, a multiplexed digital gene expression assay performed on the nCounter® Dx Analysis System and reported as GCB vs ABC vs unclassified. A comparison cohort of RCHOP treated DLBCL patients was generated from the prospectively enrolled Mayo Clinic component of the Lymphoma SPORE Molecular Epidemiology Resource (MER). MER patients meeting the same inclusion criteria as MC078E with available tissue were selected based via matching on age, stage, and IPI to the MC078E patients. Event-free survival was defined as time from diagnosis (MER) or study registration (MC078E) to progression, re-treatment, or death. EFS24 was defined as being event-free at 24 months. Associations between COO and outcome were assessed via log-rank tests due to censoring for EFS24. Results: 50 MC078E R2CHOP patients enrolled between 2008 and 2013,124 matched MER RCHOP patients diagnosed between 2003 and 2012 were assessed for COO. Median follow up in 70 patients still alive was 7.9 years (1.9-13.0) in RCHOP treated patients and 4.4 years (1.9-5.5) for 24 in R2CHOP treated patients still alive. Median age was 65 years (range 35-89) in RCHOP treated patients and 69 years (22-87) in R2CHOP patients (p=0.485). 53 RCHOP treated patients (43%) and 31 R2CHOP treated patients (62%) had intermediate-high or high IPI (p=0.021). COO was GCB, ABC, and unclassified DLBCL subtype in 80, 31 and 13 patients in the 124 RCHOP cohort and 33, 13 and 4 patients in the R2CHOP treated patients, respectively (see table). EFS24 was inferior for ABC (48%) compared to GCB DLBCL 71% in MER RCHOP treated patients (p=0.013). In contrast, in R2CHOP treated pts, EFS24 was not different between ABC vs GCB DLBCL 69% vs 67% (p= 0.674). Conclusion: Cell of origin classification of DLBCL determined by NanoString LST remains prognostic in a series of prospectively enrolled DLBCL patients treated with RCHOP. R2CHOP shows promising efficacy in ABC DLBCL as defined by NanoString LST, where the addition of lenalidomide to RCHOP appears to mitigate the negative impact of an ABC molecular subtype on the outcome. Table Table. Disclosures Nowakowski: Morphosys: Research Funding; Bayer: Consultancy, Research Funding; Celgene: Research Funding. Maurer:Kite Pharma: Research Funding; Celgene: Research Funding. Storhoff:NanoString Technologies, Inc.: Employment, Other: Stock option. Dennis:NanoString Technologies, Inc.: Employment, Other: Stock option. Gandhi:Celgene Corporation: Employment, Equity Ownership. Thakurta:Celgene: Employment, Equity Ownership. Hagner:Celgene Corporation: Employment, Equity Ownership. Rimsza:NCI/NIH: Patents & Royalties: L.M. Rimsza is a co-inventor on a provisional patent, owned by the NCI of the NIH, using Nanostring technology for determining cell of origin in DLBCL..

Abstract Introduction: The programmed death-1 (PD-1) immune checkpoint pathway regulates T-cell-mediated antitumor immune responses in solid tumors and hematologic malignancies. Nivolumab (Bristol-Myers Squibb, Ono Pharmaceutical) is a fully human IgG4 PD-1-blocking monoclonal antibody with demonstrated efficacy in a range of tumors. Results from an independent cohort of 23 pts with R/R cHL in a phase 1 study (CA209-039) showed that nivolumab was well tolerated and yielded an overall response rate (ORR) of 87% (Ansell et al, N Engl J Med, 2015). This raises important questions including the necessary duration of treatment, the relevance of the depth of response (complete response [CR] vs partial response [PR]), the duration of response, and the feasibility of retreatment. Here, we present the clinical course and post-treatment outcomes from extended follow-up of these pts to shed some light on these questions. Methods: Pts with R/R cHL received nivolumab 3 mg/kg at weeks (wks) 1 and 4, and then every 2 wks for up to 2 years (yrs). Therapy was stopped earlier in pts with intolerance to treatment or progressive disease (PD) without evidence of clinical benefit. Pts who discontinued treatment due to toxicity were followed for up to 120 days after discontinuation; other pts were followed for 1 yr after discontinuation. Responding pts discontinued after confirmed CR or 16 wks after unconfirmed CR, or continued treatment for up to 2 yrs if they had PR or stable disease (SD). Pts who discontinued treatment with ongoing CR, PR, or SD could be retreated for confirmed PD occurring <1 yr after nivolumab discontinuation. Responses were evaluated using the Revised Response Criteria for Malignant Lymphoma (Cheson et al, J Clin Oncol, 2007). The primary endpoint was safety, and the key secondary endpoint was antitumor activity. Results: A total of 23 pts with R/R cHL were treated. The median follow-up observation time is now 86 wks (range: 32-107 wks). Of 20 responders (14 PR, 6 CR), 10 have had durable responses per protocol assessment; their treatment durations and response characteristics are shown in Table 1. Responses were maintained in 2 pts (#5 and #6) after discontinuing nivolumab for >40 wks and in 1 pt (#7) after stopping due to toxicity. Eight pts with durable responses have received nivolumab for >1 yr, including 7 pts who have been in response for >1.5 yrs. One pt (#2) with an initial CR experienced a relapse 43 wks after treatment was discontinued, and achieved a second response (CR) after retreatment with nivolumab. Of the 10 remaining responders, 4 eventually progressed (time to progression [TTP] range: 21.4-92 wks), 1 discontinued treatment due to toxicity with no PD within the 120-day follow-up period, and 5 discontinued nivolumab to undergo stem cell transplant (SCT; 4 allogeneic, 1 autologous) after achieving remission. Time to CR for all responders ranged from 3-88 wks after starting nivolumab, including 2 pts with initial PRs that converted to CRs with continued treatment. All 5 pts who proceeded to SCT had responded to nivolumab within 16 wks of starting treatment (4 PR, 1 CR). Three pts had a best overall response of SD (1 discontinued due to toxicity without documented PD within the 120-day follow-up period; 2 subsequently discontinued for PD [TTP: 15 and 15.3 wks, respectively]). Overall, 3 pts discontinued nivolumab due to adverse events (AEs; Grade 2 peripheral neuropathy, Grade 3 myelodysplastic syndrome, Grade 3 pancreatitis). Grade 1 or 2 immune-related AEs (IR-AEs) occurred in 4 of 10 pts and resolved without treatment in 2 pts. The incidence of IR-AEs did not increase with time on treatment. Conclusions: In pts with R/R cHL, nivolumab was well tolerated and produced a high ORR. Responses occurred within 16 wks of nivolumab initiation in 15 of 20 pts. Early responses to nivolumab allowed 5 pts to proceed to SCT and lasted ≥1 yr in 7 of 10 pts who did not pursue SCT. One pt achieved CR again after retreatment with nivolumab when relapse occurred within 1 yr of discontinuing treatment following an initial CR. Table 1. Treatment and Response Parameters for Pts with Durable Ongoing Responses Pt # Best Response Duration of Response, wks Time to First Response, wks Time on Treatment, wks 1 PR 90.7 3.6 96+ 2 CR 82.1 7.1 91+ 3 PR 73.1 7.6 82.4+ 4 PR 71.4 14.9 88+ 5 CR 71.1 3.1 24.9 6 CR 65.1 7.1 22.9 7 PR 55.9 15.3 70.9 8 CR 48.3 39 87 9 CR 45.3 55 82.9 10 PR 41.7 38.7 82.1+ +Still on treatment Disclosures Ansell: Bristol-Myers Squibb: Research Funding; Celldex: Research Funding. Armand:BMS: Research Funding; Infinity: Consultancy, Research Funding; Sequenta, Inc.: Research Funding; Merck: Consultancy, Research Funding. Timmerman:Valor Biotherapeutics: Research Funding; Janssen: Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding. Shipp:BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy; Merck: Membership on an entity's Board of Directors or advisory committees. Bradley Garelik:Bristol-Myers Squibb: Employment. Zhu:Bristol-Myers Squibb: Employment. Lesokhin:Efranat: Consultancy; Genentech: Research Funding; Aduro: Consultancy; Janssen: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy, Research Funding.

Abstract Background: The anti-apoptotic proteins BCL-2 and MCL-1 promote multiple myeloma (MM) cell survival. Bortezomib (BTZ) can inhibit MCL-1 activity by stabilizing the MCL-1 antagonist, NOXA. Venetoclax is an orally bioavailable, highly selective BCL-2 inhibitor, which enhances BTZ efficacy in MM xenograft models. This Phase 1 study evaluates venetoclax with BTZ and dexamethasone (Dex) in patients (pts) with relapsed/refractory MM. Methods: Objectives include safety, pharmacokinetics, preliminary efficacy and maximum therapeutic dose of venetoclax with BTZ and Dex. A fixed dose of venetoclax ranging from 50 to 800 mg PO daily, according to dose cohort assignment, was given in combination in cycles (C) 1-11 and alone in C12 and beyond. Dose escalation decisions were made using the continual reassessment method. Pts received BTZ (1.3 mg/m2 SC, days [D] 1, 4, 8, 11) and Dex (20 mg PO, D1, 2, 4, 5, 8, 9, 11, 12) in cycles (C)1-8 (21D), then BTZ + Dex (D1, 8, 15, 22) in C9-11 (35D). Results: Forty-one pts were enrolled as of June 15, 2015 (pts in each cohort: 50 mg, n=3; 100 mg, n=5; 200 mg, n=6; 300 mg, n=7; 400 mg, n=6; 500 mg, n=7; 600 mg, n=5; 800 mg, n=2). Median age was 65 (38-79); 15/26 F/M. 14 were ISS stage I, 11 stage II, 11 stage III, 5 missing. Median (range) number of prior lines of therapy was 5 (1-15). Thirty-five pts had received prior BTZ (10 refractory), 34 prior lenalidomide (22 refractory); 29 had undergone stem cell transplantation. Based on FISH analysis, 5 pts had MM with t(11;14); 3 with t(4;14), 20 with del 17p, and 10 with del 13q. Treatment-emergent AEs occurring in ≥20% of pts were constipation (37%), diarrhea (37%), thrombocytopenia (32%), asthenia (29%), insomnia (29%), anemia (27%), peripheral neuropathy (27%), dyspnea (24%), peripheral edema (22%), and nausea (20%). Grade 3/4 AEs in ≥10% of pts were thrombocytopenia (20%), and anemia (17%). SAEs occurred in 18 pts; SAEs in ≥2 pts were cardiac failure, embolism, pyrexia, respiratory failure, sepsis, thrombocytopenia (n=2 each, no SAEs were venetoclax-related). Twenty-nine pts have discontinued treatment: 23 due to PD, 2 due to AEs [adenocarcinoma; cardiac and respiratory decompensation attributed to Dex (DLT at 300 mg)], and 4 withdrew consent. Three deaths occurred (all due to PD). No TLS occurred. In preliminary PK analyses (n=41), dose-normalized venetoclax exposure when given with BTZ+Dex was similar when compared to venetoclax monotherapy in MM as well as CLL and NHL pts. Forty of 41 pts were evaluable for efficacy. All responses occurred in BTZ sensitive or naïve pts. Median (range) duration or response was 5.9 (0-14.1) months in all pts, 8.5 (2.3-11.4) months in BTZ naïve pts, and 4.7 (0-14.1) months in BTZ-sensitive pts. Conclusions: Venetoclax with BTZ and Dex has an acceptable safety profile in heavily pretreated MM pts; no new safety signals were identified compared to other venetoclax studies. These early data suggest the combination of proteasome and BCL-2 inhibition resulted in anti-tumor activity. Responses were observed only in pts naïve or sensitive to prior BTZ (ORR = 100% and 58%, respectively) and occurred in all dose cohorts. The study is currently enrolling pts in the 1000 mg dose escalation cohort. Figure 1. Figure 1. Disclosures Moreau: Celgene, Janssen, Takeda, Novartis, Amgen: Membership on an entity's Board of Directors or advisory committees. Off Label Use: Venetoclax is an investigational drug that is not yet approved in this indication. Roberts:AbbVie and Genentech: Research Funding; Walter and Eliza Hall Institute of Medical Research: Employment. Agarwal:Amgen, Millennium: Consultancy; Celgene, Onyx: Speakers Bureau; AbbVie: Research Funding. Facon:Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Millenium: Membership on an entity's Board of Directors or advisory committees; Onyx: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Pierre Fabre: Membership on an entity's Board of Directors or advisory committees. Kumar:Skyline, Noxxon: Honoraria; Celgene, Millennium, Onyx, Janssen, Noxxon, Sanofi, BMS, Skyline: Consultancy; Celgene, Millennium, Onyx, Novartis, Janssen, Sanofi: Research Funding. Touzeau:AbbVie: Research Funding. Darden:AbbVie: Employment, Equity Ownership. Morris:AbbVie: Employment, Equity Ownership. Ross:AbbVie: Employment, Equity Ownership. Salem:AbbVie: Employment, Equity Ownership. Munasinghe:AbbVie: Employment, Equity Ownership. Zhu:AbbVie: Employment, Equity Ownership. Leverson:AbbVie: Employment, Equity Ownership. Maciag:AbbVie: Employment, Equity Ownership. Enschede:AbbVie: Employment, Equity Ownership. Verdugo:AbbVie: Employment, Equity Ownership. Humerickhouse:AbbVie: Employment, Equity Ownership. Harrison:Celgene: Honoraria, Research Funding; Janssen: Research Funding, Speakers Bureau; AbbVie: Research Funding.