Ansell, Stephen M.

Abstract Introduction: Classical Hodgkin lymphoma (cHL) is characterized by Reed Sternberg (RS) cells surrounded by an extensive but ineffective inflammatory/immune cell infiltrate. Recent studies suggest that Hodgkin RS cells have developed mechanisms that exploit the programmed cell death-1 (PD-1) pathway to evade immune detection. In cHL, chromosome 9p24.1 gain is a frequent structural alteration that increases the gene dosage of the PD-1 ligands, PD-L1 and PD-L2, and their induction via JAK/STAT signaling. Epstein-Barr Virus (EBV) infection also increases the expression of the PD-1 ligands in EBV-positive cHL. Ligand binding to PD-1 receptor-positive activated T cells induces “T cell exhaustion,” a reversible inhibition of T cell activation and proliferation. Nivolumab (BMS-936558, Bristol-Myers Squibb) is a fully human IgG4 monoclonal PD-1 blocking antibody that potentiates anti-tumor T cell activity, and exhibits clinical efficacy in several solid tumors. We hypothesized that nivolumab may augment anti-tumor activity in patients with relapsed or refractory (R/R) cHL, including those who had failed brentuximab vedotin (BV), and evaluated the PD-1 blocking antibody. These are the first analyses being reported with PD-1 antibody for the treatment of cHL. Methods: Patients with R/R cHL were included as an independent cohort in a dose escalation and cohort expansion phase I study of nivolumab in lymphoma and multiple myeloma (MM). Results for patients with non-Hodgkin lymphoma and MM are reported separately. Patients with cHL received nivolumab 3 mg/kg every 2 weeks until confirmed tumor progression or excessive toxicity. Responses were evaluated using standard criteria. The primary endpoint was safety; key secondary endpoints included anti-tumor activity and expression of immunomodulatory proteins in tumor biopsies. Results: Twenty-three patients were enrolled with R/R cHL. Patients were heavily pre-treated, 87% had received ≥ 3 prior treatment regimens, 78% had prior autologous stem cell transplant (ASCT), and 78% had prior BV treatment. Drug-related adverse events (AEs) of any grade occurred in 78% of patients, the most common of which were rash (22%), decreased platelet count (17%), diarrhea, nausea, pruritus, fatigue, and pyrexia (each at 13%). Drug-related grade 3/4 AEs occurred in 22% of patients. Three patients experienced 1 serious AE each (grade 3 myelodysplastic syndrome [MDS], grade 3 pancreatitis, and grade 2 lymph node pain). The objective response rate (ORR) was 87% (20/23), with 4 patients (17%) achieving a complete response (CR) and 16 (70%) obtaining a partial response (PR). The remaining 3 patients (13%) had stable disease (SD). All 23 patients had a reduction in tumor burden at 1 or more efficacy assessments during treatment with nivolumab (Figure). Among the 18 patients who had previously failed BV, the ORR was 89% (16/18), with 6% (1/18) achieving CR and 83% (15/18) PR. Progression-free survival (PFS) rate at 24 weeks was 86% (95% CI, 62-95%). The median overall survival (OS) has not been reached (range, 21+ to 75+ weeks). Six of 23 patients elected to discontinue study treatment to undergo stem cell transplantation, 2 patients discontinued due to toxicities (MDS and thrombocytopenia in 1 patient; pancreatitis in 1 patient), 4 patients discontinued due to disease progression, and 11 patients continue on study as of June 16, 2014. In a subset of study patients (10/23), PD-L1 and PD-L2 copy numbers in RS cells were assessed using fixed tumor biopsy specimens and a 3-probe fluorescence in situ assay (PD-L1,PD-L2, and control centromeric probe). In all tumors, RS cells had copy gains of PD-L1 and PD-L2, as a result of either polysomy or amplification; these tumors also exhibited increased protein expression of PD-L1. RS cells were also largely positive for pSTAT3, indicative of active JAK/STAT signaling. Conclusions In patients with R/R cHL, nivolumab-mediated PD-1 blockade is safe and tolerable with a safety profile similar to that in solid tumors. The frequent and long-lasting responses in heavily pretreated, R/R patients, including those who have failed BV, highlight the importance of the PD-1 pathway in cHL, and the genetically defined sensitivity to PD-1 blockade in this disease. Based on these results, the FDA granted nivolumab breakthrough status in relapsed cHL and a large, multinational, phase II trial of this therapy is underway. Figure 1 Figure 1. Disclosures Armand: Merck: Consultancy. Off Label Use: Nivolumab was tested for the treatment of hematologic malignancies.. Ansell:Bristol-Myers Squibb: Research Funding. Lesokhin:Bristol-Myers Squibb: Consultancy, Research Funding. Timmerman:Bristol-Myers Squibb: Research Funding. Borrello:Bristol-Myers Squibb: Research Funding. Rodig:Bristol-Myers Squibb: Research Funding. Zhu:Bristol-Myers Squibb: Employment. Grosso:Bristol-Myers Squibb: Employment, Equity Ownership. Kim:Bristol-Myers Squibb: Employment. Shipp:Merck: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: 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, Research Funding; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Sanofi: Research Funding; Janssen R&D: Membership on an entity's Board of Directors or advisory committees.

Abstract Background: Deubiquitinating enzyme (DUB) inhibitors are an emerging class of compounds, which are increasingly being regarded for their anti-cancer activity and therapeutic potential. The 19S regulatory particle of the proteasome contains two DUBs, USP14 and UCHL5, which are critical for the proper unfolding and deubiquitination of proteins prior to their entry into the 20S proteasome β-catalytic core. In B/plasma cell malignancies such as Waldenströms macroglobulinemia (WM) and multiple myeloma (MM), protein homeostasis and optimal proteasome functionality are paramount for tumor survival. This is evidenced by the success of 20S proteasome inhibition with bortezomib and carfilzomib, which have demonstrated remarkable clinical benefit in patients with WM or MM. As such, the proteasome degradation pathway represents a highly attractive and clinically validated, yet still largely unexplored therapeutic target. Here, we provide first evidence of the cytotoxic effects and molecular sequelae associated with a novel 19S proteasome DUB inhibitor, VLX1570, which selectively targets USP14 and UCHL5, in preclinical models of B/plasma cell cancers and their drug resistant tumor subclones. Materials: VLX1570 was obtained from Vivolux AB, Sweden. Bortezomib was purchased from Sellekchem, Houston TX. Human myeloma cell lines (OPM2, U266, KMS11), human WM cell lines (BCWM.1, MWCL-1 and RPCI-WM1), their respective bortezomib-resistant (BR) subclones as well as ibrutinib-resistant (IR) derivatives of BCWM.1 and RPCI-WM1 were used in experiments (total n=12). Peripheral blood mononuclear cells (PBMCs) from healthy donors were used to assess for cytotoxicity of VLX1570 in non-tumor cells. Results: A 72hr MTS assay first established sensitivity of plasma cell cancer models towards VLX1570, including drug resistant subclones (EC50 range, 20 – 90nM). Next we assessed whether loss of viability was due to apoptosis and observed dose-dependent annexin-V staining in ~50 – 70% of wild-type MM and WM cells, ~45 – 55% in corresponding BR models and ~50% in IR subclones when exposed to VLX1570 (100nm – 500nM) for 24hrs. VLX1570 was tested at similar concentrations in PBMCs and induced minimal cell death. To understand if VLX1570-induced apoptosis was mitochondrial mediated, we assessed mitochondrial outer membrane permeability (MOMP) in all plasma cell cancer models treated with the DUB inhibitor (100 – 500nM) and found a dose-dependent increase in MOMP (p<0.00025 – 0.000001). Activation of the mitochondrial/intrinsic apoptotic pathway was also evidenced by cleavage of caspase-9 and 3 on immunoblot analysis. As inhibition of protein deubiquitination results in accumulation of polyubiquitinated protein conjugates, we examined global ubiquitinated protein levels and found increasing amounts of high molecular weight poly-ubiquitinated protein in VLX1570 treated tumor cells in a dose-dependent manner. This prompted us to further delineate the potential cellular response mechanisms that relay the antitumor activity of VLX1570 in malignant plasma cells. Immunoblot analysis of drug sensitive and (bortezomib or ibrutinib) resistant MM and WM cell lines revealed several changes in ER stress response proteins, notably induction of HSP70 and splicing of XBP1; the latter event which was less prominent in BR cell lines treated with bortezomib. This suggested the ability of VLX1570 to overcome resistance through a rapid and potent proteotoxic effect, which overwhelmed the tumor cells stress response mechanisms beyond its capacity for survival. Finally, as abnormalities in the NFkB signaling pathway are implicated in malignant plasma cell survival, we found markedly decreased nuclear translocation of NFkB (p-P65) protein in tumor cells treated with VLX1570. Conclusions: The DUBs of the 19S proteasome cap offer an attractive target within the proteasome degradation system and whose inhibition by VLX1570 is able to circumvent mechanisms that support resistance to b-catalytic PI (bortezomib) or BTK inhibitor (ibrutinib) therapy. The studies undertaken thus far, coupled with more rigorous mechanistic and in vivo efficacy analyses currently underway, provides rational for the clinical development of DUB inhibitors for use in malignant B/plasma cell malignancies. Disclosures Martin: Janssen: Honoraria.

Abstract Background Patients (pts) with Hodgkin lymphoma (HL) who have relapsed/refractory disease after frontline therapy typically undergo salvage chemotherapy followed by high-dose conditioning and autologous stem cell transplant (ASCT). Improved outcomes have been reported for pts who achieve complete remission (CR) with salvage chemotherapy prior to ASCT. Variable CR rates (19%-60%) and significant toxicities are associated with standard salvage therapy in the first relapse setting. Brentuximab vedotin and bendamustine have independent mechanisms of action and are highly active with manageable safety profiles when administered as single agents to pts with HL who relapse after ASCT (brentuximab vedotin: 34% CR [Younes, 2012]; bendamustine: 33% CR [Moskowitz, 2013]). This phase 1/2, single-arm, 2-stage, open-label study was designed to evaluate the safety and efficacy of brentuximab vedotin in combination with bendamustine for the treatment of pts with HL in first relapse (ClinicalTrials.gov #NCT01874054). Methods Pts received an outpatient IV infusion of 1.8 mg/kg brentuximab vedotin on Day 1 with 90 mg/m2 bendamustine on Days 1 and 2 of 3-week cycles for up to 6 cycles. Pts could undergo ASCT any time after Cycle (C) 2 and post-transplant resume treatment with brentuximab vedotin as monotherapy for up to16 total doses. Phase 1 was designed to determine the recommended dose of bendamustine in combination with brentuximab vedotin. During this phase, the dose of bendamustine was to be de-escalated if ≥4/10 pts experienced dose-limiting toxicity (DLT), defined as any C1 toxicity requiring a dose delay of ≥14 days. During phase 2, bendamustine was administered at the recommended dose in order to assess the CR rate of the combination. Response was assessed by the investigator per Cheson 2007. Results Forty-five pts (58% female) with a median age of 35 yrs (range, 19-79) have been enrolled. Fifty-eight percent of pts had relapsed disease and 42% of pts primary refractory disease after frontline therapy. A median of 13.1 mos (range, 3- 98) had elapsed since initial diagnosis. No DLTs were observed in the safety cohort, thus the recommended dose of bendamustine in combination with brentuximab vedotin was 90 mg/m2. Pts received a median of 2 cycles (range, 1-6) of the combination. The main toxicity observed with the combination was infusion-related reactions. The most common symptoms (≥10%) were dyspnea (13%), flushing (13%), and chills (11%). The majority of reactions occurred within 24 hours of C2 infusion and were considered related to both agents. Premedication with corticosteroids and antihistamines was instituted with a protocol amendment and appeared effective. Prior to the amendment, 36% (9/25 unique pts) of treated pts had reactions that were either serious adverse events (SAEs) (n=6), Grade 3 in severity (n=8), and/or led to treatment discontinuation (n=6). Following premedication implementation, 15% (3/20 unique pts) of treated pts had such events (0 SAEs, 1 treatment discontinuation, and 2 Grade 3 toxicities). The CR rate of the combination was 82% (28/34 pts evaluable for response) and the overall objective response rate (CR and partial remission) 94% (32/34 pts). The majority of CRs (24/28 pts) were achieved after 2 cycles of combination therapy. Stem cell mobilization and collection was considered adequate in all 24 pts who underwent the procedure. The median number of CD34+ cells collected was 4.3 x106 (range, 1.7- 16.0 x106) in a median of 2 apheresis sessions (range, 1-5). To date, 20 pts have undergone ASCT, the majority after C2 (12 pts) or C3 (6 pts), and 13 pts have resumed brentuximab vedotin as monotherapy. One patient with CR developed progressive disease 3 cycles post-transplant. The median duration of remission for pts who obtained a CR has not been reached (95% CI: 8.7,– [range, 0.03+-10.4+ months]). Conclusions The outpatient regimen of brentuximab vedotin 1.8 mg/kg on Day 1 in combination with bendamustine 90 mg/m2 on Days 1 and 2 of 3-week cycles has a manageable safety profile with premedication. The very high CR rate observed on combination treatment compares favorably with historical data. The durability of responses observed to date and the success of stem cell mobilization and collection suggest that the regimen may represent a promising approach for maximizing responses prior to ASCT in pts with HL who are either relapsed or are refractory after frontline therapy. Disclosures LaCasce: Seattle Genetics, Inc.: Research Funding. Off Label Use: Brentuximab vedotin is indicated in the US for treatment of patients with Hodgkin lymphoma after failure of autologous stem cell transplant or after failure of at least two prior multi-agent chemotherapy regimens in patients who are not ASCT candidates and for the treatment of patients with systemic anaplastic large cell lymphoma after failure of at least one prior multi-agent chemotherapy regimen. Bociek:Seattle Genetics, Inc.: Research Funding. Matous:Celgene: Consultancy, Speakers Bureau; Onyx: Speakers Bureau; Takeda Pharmaceuticals International Co.: Speakers Bureau; Seattle Genetics, Inc.: Research Funding, Speakers Bureau. Sawas:Seattle Genetics, Inc.: Research Funding. Caimi:Seattle Genetics, Inc.: Equity Ownership, Research Funding. Ansell:Seattle Genetics, Inc.: Research Funding. Islas-Ohlmayer:Seattle Genetics, Inc.: Research Funding. Cheung:Seattle Genetics, Inc.: Research Funding. Agura:Seattle Genetics, Inc.: Research Funding. Behler:Onyx Pharmaceuticals: Speakers Bureau; Seattle Genetics, Inc.: Research Funding. Crosswell:Seattle Genetics, Inc.: Consultancy, Equity Ownership, Research Funding, Travel expenses Other. Vose:Seattle Genetics, Inc.: Honoraria, Research Funding. Josephson:Seattle Genetics, Inc.: Employment, Equity Ownership. Advani:Janssen Pharmaceuticals: Research Funding; Genentech: Research Funding; Pharmacyclics: Research Funding; Celgene: Research Funding; Takeda International Pharmaceuticals Co.: Research Funding; Seattle Genetics, Inc.: Research Funding, Travel expenses Other.

Abstract Introduction DLBCL is the most common lymphoid neoplasm in adults (Swerdlow 2016). While durable CRs are achieved in approximately 70% of patients (pts) with frontline RCHOP therapy (Pfreundschuh 2008), pts with high-risk features often experience disease resistance or relapse. In Part 1 of an ongoing study, pts with high-intermediate or high risk DLBCL by international prognostic index (IPI) scores, regardless of CD30 expression by IHC, were treated with 1.2 or 1.8 mg/kg brentuximab vedotin (BV) combined with RCHOP. After 3 of the first 10 pts treated at 1.8 mg/kg BV+RCHOP developed Grade 3 peripheral neuropathy (per Standardized MedDRA Query [SMQ]), all pts enrolled subsequently received treatment with 1.2 mg/kg BV+RCHOP. Following completion of enrollment in Part 1, the protocol was amended to enroll a non-randomized portion of the study (Part 2) evaluating the safety and efficacy of 1.8 mg/kg BV+RCHP (Yasenchak 2015), followed by an open-label, randomized portion comparing BV+RCHP to RCHOP (Part 3). Initial results from Part 2 and updated results from Part 1 are reported here. Methods For Part 2 of the study, pts with CD30-expressing high-intermediate and high-risk DLBCL were treated with up to 6 cycles of 1.8 mg/kg BV+RCHP (NCT01925612). Key inclusion criteria were CD30 expression by IHC performed by a local pathology lab and standard IPI scores of 3-5 or age-adjusted IPI (aaIPI) scores of 2-3 (high-intermediate/high risk). CD30 expression was confirmed by a central pathology lab, although CD30 expression by local pathology lab was required for eligibility. Disease response was evaluated with PET/CT per Cheson 2007. Results At the time of analysis for this ongoing study, 11 pts in Part 2 were treated with BV+RCHP (7 male, 4 female; 22-78 yrs). Of these pts, 9 had high-intermediate risk (IPI 3, aaIPI 2) and 2 had high risk disease (IPI 4-5, aaIPI 3), 6 had Stage IV disease, and 6 had an ECOG score of 2. At the end of treatment, the overall response rate was 91% (9 CR, 1 PR); 1 pt had PD after Cycle 4. The most frequent (>20%) treatment-emergent adverse events (AEs) were alopecia and nausea (73% each); fatigue (64%); constipation and peripheral sensory neuropathy (55% each); neutropenia and throat irritation (36% each); and chills, diarrhea, headache, and stomatitis (27% each). Grade 3 or 4 AEs occurred in 8 pts and 5 pts had serious AEs, which included febrile neutropenia, bacteremia, nausea, pneumocystis jiroveci pneumonia, pulmonary embolism, and vomiting. Peripheral sensory neuropathy occurred in 6 pts and all were Grade 1 or 2 events; no peripheral motor neuropathy AEs were reported. No AEs were fatal or led to discontinuation. One pt discontinued treatment after Cycle 4 due to disease progression. For the first 51 pts in Part 1, the progression-free survival (PFS) at 18 months for pts with CD30 expression (25 pts) or without detectable CD30 expression (24 pts) by IHC was 79% (95% CI: 57%, 91%) versus 58% (95% CI: 36%, 75%), respectively. Overall survival for pts was 92% (95% CI: 71%, 98%) versus 71% (95% CI: 48%, 85%), respectively. Ten pts had pre-existing peripheral neuropathy (per SMQ) at study entry. Treatment-emergent peripheral neuropathy (per SMQ) was observed in 75% of pts (38/51) who received BV+RCHOP; 55% of these pts (21/38) had resolution of all or some peripheral neuropathy events. Conclusions 1.8 mg/kg BV+RCHP is active as frontline treatment in CD30-expressing, high-intermediate/high risk DLBCL. When combined with RCHP, 1.8 mg/kg BV appears to be well-tolerated. The PFS and OS for pts with CD30-expression who received BV+RCHOP appear promising. The study is currently ongoing in pts with CD30-expressing high-intermediate/high risk DLBCL to assess the safety and activity of 1.8 mg/kg BV+RCHP versus standard RCHOP. Disclosures Halwani: Bristol Myers-Squibb: Research Funding; Kyowa Hakko Kirin: Research Funding; Takeda: Research Funding; Genentech: Research Funding; AbbVie: Consultancy, Other: Travel Expenses, Research Funding; Seattle Genetics: Consultancy, Research Funding; Immune Design: Research Funding; Miragen: Research Funding; Pharmacyclics: Consultancy; Amgen: Research Funding. Yasenchak:Seattle Genetics: Research Funding. Farber:Seattle Genetics: Research Funding. Burke:Pfizer: Consultancy; Janssen: Consultancy; Incyte: Consultancy; TG Therapeutics: Other: Travel Expenses; Millenium: Consultancy. Fayad:Seattle Genetics: Consultancy, Research Funding. Holkova:Seattle Genetics: Research Funding. Knapp:Insys Therapeutics, Inc.: Consultancy, Other: Travel, Accommodations, Expenses; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding. Kolibaba:Gilead: Consultancy, Research Funding; Celgene: Research Funding; TG Therapeutics: Research Funding; Takeda Pharmaceuticals International Co.: Research Funding; Seattle Genetics: Research Funding; Pharmacyclics: Research Funding; janssen: Research Funding; GSK: Research Funding; Genentech: Research Funding; Acerta: Research Funding. Patel-Donnelly:Seattle Genetics: Research Funding. Yimer:Ariad Pharmaceuticals: Consultancy; Biotheranostics: Consultancy; Bluebird Bio: Equity Ownership; Kite Pharma: Equity Ownership; Clovis Oncology: Equity Ownership; Juno Therpeutics: Equity Ownership; Seattle Genetics: Research Funding. Smith:Celgene: Consultancy, Speakers Bureau; Seattle Genetics: Research Funding. Levy:Janssen: Speakers Bureau; Amgen: Speakers Bureau; Takeda Pharmaceuticals International Co.: Speakers Bureau; Seattle Genetics: Research Funding; Actinium Pharmaceuticals, Inc.: Research Funding. Seetharam:Seattle Genetics: Research Funding. Belada:Seattle Genetics: Research Funding. Brooks:Seattle Genetics: Research Funding. Kingsley:Gilead: Equity Ownership; Pharmacyclics LLC, an AbbVie Company: Equity Ownership. Wagner-Johnston:Seattle Genetics: Research Funding. Ruffner:Forma Therapeutics: Consultancy; Sydnax: Consultancy; Seattle Genetics: Employment, Equity Ownership; Array Biopharma: Employment; Medivation: Employment. Bartlett:Gilead: Consultancy.

Abstract Regulatory T-cells (TREG) are the gateway to immune function and typically regulate immune cell activation. Cytokines, including interleukin-2 (IL-2), induce T-cell differentiation and promote a regulatory phenotype. Once activated via the IL-2 receptor (IL-2R), a cascade of events in T-cells initiate signal transducer and activator of transcription 5 (STAT5) and Forkhead box P3 (FOXP3) activation which appear to function as important regulators of this immunologic pathway and promote the development and function of TREG cells. In non-Hodgkin lymphoma (NHL), we have found that intratumoral TREG cells are increased in number and suppress immune function. In previous work, we have found that TREG cells inhibit T-cell proliferation, suppress cytokine production and limit effector cell cytotoxicity. We have also shown that increased serum levels of soluble sIL-2Rα is a prognostic factor in NHL and that sIL-2Rα can bind to IL-2 and promote its signaling thereby increasing TREG cell numbers. In this study, we developed a strategy to inhibit the binding of IL-2 to sIL-2Rα with the goal of suppressing the induction of FOXP3 and decreasing TREG cell numbers. To do this, we developed peptides designed to disrupt the interaction between IL2 and sILRα. In collaboration with CMDBioscienceSM, we developed and analyzed 22 peptide compounds derived by structure-based computational design. Initially, we screened each peptide at increasing concentrations using an ELISA assay to test the inhibition of IL-2/IL-2Rα binding by the solubilized peptide. Candidate peptides were then further tested using upregulation of pSTAT5 and FOXP3 in T-cells measured by flow cytometry as a measure of inhibition of IL-2 signaling. The peptides were developed according to different design hypotheses and grouped into different families; the screening ELISA results indicated 4 promising peptides that inhibited IL2/IL2Rα binding (up to 100% inhibition; max peptide concentration of 100uM). These peptides were then used to determine their effect on STAT5 and FOXP3 expression. A lead candidate peptide consistently reduced the expression of FOXP3 and STAT5 expression compared to cells not exposed to peptide. Use of the peptide to disrupt IL-2 signaling inhibited the development of cells with a TREG phenotype. We conclude that structure-based peptide design can be used to identify novel peptide inhibitors that block IL-2/IL-2Rα signaling and inhibit STAT5 and FOXP3 upregulation. These peptides could be used as new therapeutic agents to limit immune suppression by TREG cells and promote a more effective anti-tumor immune response in NHL. Disclosures No relevant conflicts of interest to declare.

Abstract Background: EBV+ DLBCL not otherwise specified (EBV+ DLBCL NOS) is defined by the 2016 WHO Classification of Tumors of Hematopoietic and Lymphoid Tissues as EBV+ DLBCL in patients without a history of known immunosuppression. Among Asian patients, adverse outcomes have been associated with EBV+ vs EBV- DLBCL, and circulating EBV has been found in the majority of patients. Outcome studies of unselected North American patients are few and non-confirmatory. No formal assessment of immunosuppression status has been incorporated into these analyses, leading to the variable inclusion of patients with a history of immunocompromised states. We sought to determine the prevalence, presenting clinical and pathology characteristics, and outcomes of DLBCL by EBV and immunosuppression status in an unselected prospective cohort study of North American patients. Methods: From 2002-2012, we enrolled consecutive, newly diagnosed patients with lymphoma who were ≥ 18 years and HIV negative into the Molecular Epidemiology Resource (MER). Clinical, laboratory, and treatment data were abstracted from medical records. All DLBCL patients with available tissue microarrays (TMAs), excluding primary mediastinal DLBCL and post-transplant lymphoproliferative disorders, were included. Medical records were reviewed using a standard protocol to classify patients as immunocompromised based on a documented history of primary immunodeficiency or iatrogenic immunosuppression. DLBCL cell of origin was classified as germinal center (GCB) vs non-GCB using the Hans algorithm. CD30 was determined using immunohistochemistry; positivity cutoff was 20% of neoplastic cells. EBV testing was performed by in-situ hybridization for EBV encoded small RNAs (EBERs), and scored by an expert hematopathologist. Event free survival (EFS) was defined as time from diagnosis until recurrence, retreatment, or death due to any cause. Associations with EFS and Overall Survival (OS) were obtained using the methods of Kaplan-Meier (KM). Hazard Ratios (HRs) and 95% confidence intervals (CIs) were estimated from Cox regression models. Results: 1,100 patients with DLBCL were enrolled into the MER; 362 had TMAs available for this analysis. Median age was 63 years (range 20-89) and 59% were male. 89.5% of patients were treated with immunochemotherapy. 16 cases (4.4%) were EBV+, and 39 cases (10.8%) were considered immunocompromised. EBV positivity was more common in immunocompromised vs immunocompetent patients, with a trend towards significance (10.3% vs 3.7%; P = 0.08). The non-GCB subtype was more frequent in EBV+ vs EBV- DLBCL (62.5% vs 34.1%; P < 0.01), but similar between immunocompromised vs immunocompetent patients (48.7% vs 33.7%; P = 0.10). CD30 positivity was also more frequent in EBV+ vs. EBV- DLBCL (25.0% vs 8.1%; P < 0.01), but similar between immunocompromised vs immunocompetent patients (12.8% vs 8.4%, respectively; P = 0.45). With a median follow-up of 59 months (range 0.7-155.2) there were 151 events and 119 deaths. KM curves by EBV and immunosuppression status are shown in the figure. There was no association of EBV positivity with EFS (HR = 0.76; 95% CI 0.34-1.72) or OS (HR = 0.99; 95% CI 0.43-2.25). A history of immunosuppression was not associated with EFS (HR = 1.17; 95% CI 0.72-1.89) or OS (HR = 1.02; 95% CI 0.58-1.78). In the subset of immunocompetent patients, there was no association of EBV positivity with EFS (HR = 0.54; 95% CI 0.17-1.70) or OS (HR = 0.71; 95% CI 0.23-2.25). Similar results were obtained after adjustment for the International Prognostic Index. Circulating viral DNA was detected in 2/5 EBV+ and 4/49 EBV- DLBCL patients. Conclusions: The prevalence of EBV+ DLBCL NOS is <5% among patients in a large North American cohort, similar to other western populations. There was no evidence of an association of EBV or immunosuppression status with EFS or OS, with low power for detecting associations with EBV. Circulating viral DNA was infrequent among either EBV+ or EBV- DLBCL patients. While immunosuppression has been previously shown to be a risk factor for DLBCL, it was not found to be associated with EFS or OS. Overall, these results suggest divergent outcomes among EBV+ DLBCL patients between western and non-western populations, underscoring differences in host factors or circulating viral strains. Disclosures Ansell: BMS, Seattle Genetics, Merck, Celldex and Affimed: Research Funding.

Abstract Introduction New treatment strategies are improving outcomes for patients with Hodgkin (HL) and non-Hodgkin lymphoma (NHL) but achieving durable responses and cure in the relapsed patient remain a challenge. Both the mTORC1 inhibitor everolimus (RAD001) and the IMiD, lenalidomide (LEN) have efficacy as single agents in patients with relapsed and refractory (R/R) HL and NHL. Individually, LEN and RAD present a low toxicity profile and in combination may offer synergistic therapeutic efficacy by unique mechanisms of action. A phase I/II clinical trial of RAD and LEN was designed to explore the tolerability, toxicity and to determine the maximum tolerated dose (MTD) of this combination for the Phase II study. The results of phase I/II data are reported here. Methods MC0981 was activated on January 10, 2011. In phase I, the study enrolled a total of 25 patients and RAD 5 mg daily + LEN 10 mg/d X 21d in a 28-day cycle was defined as the MTD. The phase II opened on May 14, 2013, and closed on Feb 19, 2014, during which 33 patients were enrolled and were treated until progression of disease. Eligibility required age ≥18, biopsy proven relapsed or refractory NHL or HL, ECOG PS 0- 2, measurable disease, Hb >9g/dl, ANC ≥1200/uL, platelet ≥ 50,000/uL, creatinine ≤1.5xULN and willingness to sign informed consent. Women of child bearing potential had pregnancy testing and all patients followed recommendations for contraception. Follow up data was analyzed as of July 2014. Results A total of 58 patients were enrolled to this study and fifty five are evaluable for analysis (2 never started therapy, 1 deemed ineligible). The median age was 62 years (21-82) and 38 (69.1%) were male. Sixty-five percent had stage IV disease and 42% had 4 or more prior treatments including stem cell transplantation in 49%. Histologies included HL (n=10) and NHL (n=45 with 23 DLBCL, 2 FL-III, 5 LPL, 3 MCL, 2 MF, and 3 other). At least 1 Gr≥3 adverse event was seen in 74.5% of patients. The most common Gr≥3 toxicities were hematologic - neutropenia (30.9%), and thrombocytopenia (21.8%), and anemia (10.9%). Nine of 55 patients (16%) had Gr≥3 infection; 2 with skin infection, 1 with cholecystitis, 1 with lung infection, 1 with pharyngitis 1 with otitis externa, 1 with otitis media, and 1 with pleural infection and 1 with upper respiratory tract infection. Seven patients discontinued treatment due to adverse events. At this time, 44% (25/55) remain progression-free. A documented tumor response, as overall response rate (ORR) was seen in 20% (11/55) with 1CR, 8PR, and 2MR; 17 remain on therapy; and 22 deaths have occurred with a median survival of 15.0 months (95% CI 7.5-NR). Median follow up time was 5.5 (range, 0.7- 41.0) months. The median duration of response (DOR) in those responding is 19.4 months. Conclusions In a heavily pretreated population with baseline compromised bone marrow function, the combination of everolimus and lenalidomide is feasible with a modest ORR and a surprisingly long DOR. Future studies in more defined groups of NHL or HL are necessary to better predict which patients will be long-term responders. This trial is sponsored by Novartis and Celgene Disclosures Off Label Use: mTORC1 inhibitor (Everolimus) and the Immunomodulatory (IMiD) drug Lenalidomide for patients with Heavily Pretreated Relapsed Lymphoma . Mikhael:Onyx: Research Funding; Celgene: Research Funding; Sanofi: Research Funding; Novartis: Research Funding. Nowakowski:Celgene, Morphosis: Consultancy. Witzig:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding. Reeder:Millennium, Celgene, Novartis: Research Funding.

Abstract Introduction: Nivolumab, a fully human IgG4 monoclonal antibody targeting programmed death receptor-1, has recently been FDA approved for classical Hodgkin lymphoma (cHL) that has relapsed or progressed after autologous stem cell transplantation (ASCT) and post-transplantation brentuximab vedotin (BV). CheckMate 205 (NCT02181738) is a phase 2, international, multicohort study evaluating nivolumab monotherapy in patients with cHL after failure of ASCT. At minimum 6 months' follow-up of Cohort B (205B) which included patients who had received BV after disease recurrence following ASCT, objective response rate (ORR) per independent radiologic review committee (IRRC) was 66% and 6-month progression-free survival (PFS) was 77%, with an acceptable safety profile (Younes et al. Lancet Oncol 2016; Jul 20 [Epub ahead of print]). Here we report outcomes with longer follow-up (minimum 12-month follow-up) in 205B. Primary results from Cohort A, which enrolled patients who relapsed after ASCT but were BV-naïve, will also be presented for the first time as data were not available at time of abstract submission. Methods: CheckMate 205 was designed to evaluate the efficacy and safety of nivolumab monotherapy in patients with cHL who relapsed after ASCT in 3 cohorts: 205A (BV-naive patients; n = 63); 205B (BV after failed ASCT; n = 80); 205C (BV at any time prior to study drug; n = 100). Nivolumab was given at 3 mg/kg intravenously every 2 weeks until disease progression or unacceptable toxicity in 205A and 205B. The primary endpoint was IRRC-assessed ORR. Results: 80 patients were treated in Cohort 205B; the median age was 37 years (range 18-72). Patients had received a median of 4 prior regimens (range 3-15). At data cut-off (April 2016) with median duration of follow-up of 15.4 months (range 1.9-18.5), 43 patients (54%) still remained on therapy. IRRC-assessed ORR for patients in 205B was 68% (95% confidence interval [CI], 56%, 78%). CR and partial response (PR) rates per IRRC were 8% (3%, 16%) and 60% (48%, 71%), respectively. With longer follow-up, the median duration of response was prolonged to 13.1 months (95% CI, 8.7, not reached; range, 0.0+, 14.2+). The median duration of CR (DOCR) was not reached (95% CI, 4.6, not available [NA]; range, 0.7+, 10.4+) and the median duration of PR was 13.1 months (95% CI, 7.79, NA; range, 0.0+, 13.4+) (Table 1). IRRC median PFS was 14.8 months (95% CI, 11.3 months, NA); 12-month PFS was 54.6% (95% CI, 40.9%, 66.4%), and 12-month overall survival (OS) was 94.9% (median OS not reached). Of 37 patients (46%) who discontinued nivolumab, the most common reasons were disease progression (n = 19 [24%]), allogeneic stem cell transplant (n = 7 [9%]) and adverse events (n = 5 [6%]). Seventy-four patients (93%) had drug-related adverse events (AEs) of any grade. The most common drug-related AEs were fatigue (28%), infusion reaction (20%), arthralgia (15%), and rash (15%). 29% of patients had Grade 3-4 drug-related AEs; the most common were increased lipase (8%), neutropenia (5%), and increased aspartate aminotransferase (4%). The most common serious AEs were pyrexia, pneumonia, tumor progression, arrhythmia, infusion reaction, and meningitis (≤4% each). Conclusions: In this report with extended 12-month follow-up, longer remissions are noted following nivolumab monotherapy in relapsed cHL, including durable PRs in heavily pretreated patients. Nivolumab has an acceptable safety profile, similar to previously reported. Primary results following nivolumab monotherapy in BV-naïve patients with cHL who progressed after ASCT (Cohort 205A) will also be presented at the meeting. Study funding: Study funded by Bristol-Myers Squibb. Professional writing assistance was provided by K. Jesien of Caudex and funded by Bristol-Myers Squibb. Disclosures Timmerman: Seattle Genetics, Genmab, Celgene: Consultancy, Honoraria; Bristol-Myers Squibb, Kite Pharma, Valor Biopharmaceuticals, Janssen: Research Funding. Engert:Takeda, BMS: Consultancy, Honoraria, Research Funding. Armand:Bristol-Myers Squibb: Consultancy, Research Funding; Pfizer: Research Funding; Roche: Research Funding; Infinity Pharmaceuticals: Consultancy; Merck: Consultancy, Research Funding; Sequenta Inc: Research Funding. Collins:Takeda: Consultancy, Honoraria, Speakers Bureau. Kuruvilla:Roche Canada: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Amgen: Honoraria; Merck: Honoraria; BMS: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Lundbeck: Honoraria. Cohen:Millennium/Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: 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; Pharmacyclics: 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; Bristol-Myers Squibb: Research Funding. 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. De Boer:NKI-AVL: Employment. Shipp:Cell Signaling: Honoraria; Merck, Gilead, Takeda: Other: Scientific Advisory Board; Bayer: Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding. Rodig:Bristol-Myers Squibb: Honoraria, Research Funding; Perkin Elmer: Membership on an entity's Board of Directors or advisory committees. Kato:Bristol-Myers Squibb: Employment. Sumbul:Bristol-Myers Squibb: Employment. Ansell:BMS, Seattle Genetics, Merck, Celldex and Affimed: Research Funding.

Abstract Background: Despite advances in chemotherapy, relapsed/refractory (R/R) Hodgkin lymphoma (HL) remains a significant clinical challenge and an unmet medical need. HL has a unique biology in which a small number of malignant Hodgkin Reed-Sternberg (HRS) cells propagate an immunosuppressive microenvironment. We hypothesized that using immune checkpoint inhibitor therapy to activate the immune cells in the tumor microenvironment, and concurrently targeting HRS cells with the CD30 antibody-drug conjugate brentuximab vedotin (BV), could overcome tumor cell resistance. E4412 is a Phase 1 ECOG-ACRIN sponsored study of the combination of BV and ipilimumab (IPI) and nivolumab (Nivo) in patients with R/R HL. Here we present the preliminary safety and response data on the patients treated with BV + Nivo (Arms D and E). Methods: Patients with confirmed R/R HL were treated with Nivo 3mg/kg and BV 1.2mg/kg (Arm D: Dose Level 1) or 1.8mg/kg (Arm E: Dose Level 2) in dose escalation with a 3+3 design and an expansion cohort (Arm F) of 9 patients. BV and Nivo are given every 21 days for 16 cycles; Nivo may be continued for an additional year (total 2 years of Nivo therapy). Dose limiting toxicity (DLT) was defined for purposes of dose escalation within the first cycle of therapy. Patients are followed for toxicity up to 30 days beyond their last treatment. Results: As of 7/20/2016 10 patients (1 ineligible) have been treated with BV + Nivo. We report the data on the dose escalation population: 3 patients: Arm D, 7 patients: Arm E. Data will be updated to include the full BV + Nivo dose escalation and dose expansion cohorts (Arms D, E & F) (N = 19) by the time of the Annual Meeting. Median age was 46; (range: 25-53). Six patients were male. Patients were heavily pretreated with a median of 3 prior therapies. Six patients had prior SCT (5 autologous, 1 allogeneic); 2patients had prior treatment with BV. Safety: Ten of 10 patients are evaluable for safety. Overall safety profiles show that the regimen of BV + Nivo was extremely well tolerated. One patient out of 7 in dose level 2 experienced a DLT (pneumonitis grade 3 with grade 3 dyspnea and hypoxia, and typhilits grade 3), this patient had received a prior SCT, and made a full recovery from his toxicities. Per protocol he discontinued further therapy. No other DLTs were noted for the remaining 9 patients. Common and relevant toxicities considered at least possibly related to drug during any cycle of treatment are shown in Table 1. There were no Grade 4 treatment related adverse events (AEs). The only additional grade 3 AEs noted were one each grade 3 rash and puritis. The most common grade 1-2 treatment related adverse events were: transaminitis (9), peripheral sensory neuropathy (6), and rash (3). Other AEs of interest included: diarrhea (3), blurry vision (2), and myalgias (2). One grade 1-2 infusion reaction was noted, this patient was able to receive subsequent therapy with pre-medication. Response: Eight of 10 patients are evaluable for response. One patient is not yet evaluable. For the 8 evaluable patients the overall response rate (ORR) for the combination of BV + Nivo was 100%, with a CR rate of 62.5% (5/8), with 95% CI of 0.25-0.91. One patient was ineligible for laboratory studies that were out of range at screening, however this patient continues on therapy, and also had a response. One of 5 CRs occurred at in dose level 1 (BV 1.2 mg/kg). Both patients who had been treated with prior BV achieved CRs. The progression free survival (PFS) to date is 100% with a median follow-up of 0.3 years. Conclusion: In this first reported study of the combination of the checkpoint inhibitor Nivo and the ADC BV therapy was well tolerated with one DLT, and primarily grade 1 and 2 toxicities. In a heavily pretreated patient population, 20% of whom had had prior BV and 60% of whom were s/p ASCT, the ORR of 100% and CR rate of 62.5% suggests a deepening of response compared to either therapy alone. Optimization of this combination strategy is planned with ongoing accrual to cohorts receiving BV + Nivo, and BV + Ipi + Nivo. Data will be updated to include the full BV + Nivo cohort (N = 19) by the time of the Annual Meeting. Disclosures Diefenbach: Seattle Genetics: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Research Funding; Merck: Research Funding; Genentech: Research Funding; Incyte: Research Funding; LAM Therapeutics: Research Funding; Molecular Templates: Research Funding; Oncomed: Research Funding; This study was coordinated by the ECOG-ACRIN Cancer Research Group (Robert L. Comis, MD and Mitchell D. Schnall, MD, PhD, Group Co-Chairs) and supported by the National Cancer Institute of the National Institutes of Health under the following award number: Research Funding. Hong:This study was coordinated by the ECOG-ACRIN Cancer Research Group (Robert L. Comis, MD and Mitchell D. Schnall, MD, PhD, Group Co-Chairs) and supported by the National Cancer Institute of the National Institutes of Health under the following award number: Research Funding. Cohen:Seattle Genetics: Consultancy, Honoraria, Research Funding; BMS: Research Funding. Advani:Stanford University: Employment; Juno: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Research Funding; Spectrum: Consultancy, Honoraria; Sutro: Consultancy, Honoraria; Genentech: Consultancy, Honoraria, Research Funding; Kura: Research Funding; Merck: Research Funding; Celgene: Research Funding; Janssen: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Agensys: Research Funding; Pharmacyclics: Research Funding; Infinity: Research Funding; Millennium: Research Funding; FortySeven: Consultancy, Honoraria; Kyowa Hakko Kirin: Consultancy, Honoraria. Kahl:This study was coordinated by the ECOG-ACRIN Cancer Research Group (Robert L. Comis, MD and Mitchell D. Schnall, MD, PhD, Group Co-Chairs) and supported by the National Cancer Institute of the National Institutes of Health under the following award number: Research Funding. Ansell:BMS, Seattle Genetics, Merck, Celldex and Affimed: Research Funding.

Abstract Background Brentuximab vedotin (BV) is an antibody-drug conjugate directed against CD30, a receptor that engages the CD30 ligand expressed on immune cells in the tumor microenvironment, promoting tumor cell growth (Montanari 2014, Hansen 2014). Through disruption of the microtubule network, BV induces apoptotic cell death, and may initiate an antitumor immune response (i.e., immunogenic cell death) through the induction of endoplasmic reticulum (ER) stress (Gardai 2015). Nivolumab is a fully human monoclonal PD-1 blocking antibody that prevents tumor immune evasion. Both agents have independent high single-agent response rates in patients (pts) with relapsed or refractory (R/R) Hodgkin lymphoma (HL), and when used in combination, may exhibit mechanistic synergy. Given the demonstrated efficacy of both BV and nivolumab, together these agents could yield improved CR rates prior to ASCT in pts with R/R HL, and potentially better long-term outcomes. Methods A phase 1/2 study is ongoing to evaluate the safety and antitumor activity of BV administered in combination with nivolumab as first salvage therapy in pts with R/R classical HL after standard frontline chemotherapy (NCT02572167). Adult pts are treated in 21-day cycles for up to 4 cycles (12 weeks). Pts receive 1.8 mg/kg BV on Cycle 1 Day 1, and 3 mg/kg nivolumab on Cycle 1 Day 8. For cycles 2 through 4, BV and nivolumab are administered on Day 1 of each cycle at the same doses. After completion of the Cycle 4 response assessment, pts are eligible to undergo ASCT. Investigator assessment of lymphoma response and progression is per the Lugano Classification Revised Staging System for malignant lymphoma (Cheson 2014). Results Twenty-five pts (60% female) with a median age of 32 years (range, 18-69) have been enrolled to date. Sixty percent of pts have relapsed disease, 36% have primary refractory disease (failure to achieve CR with frontline therapy, or relapse within 3 months of completing frontline therapy), and 1 pt (4%) has unknown status. At the time of enrollment, 32% of pts presented with extranodal disease and 16% with bulky disease. At the time of the data extract, 23 pts had received treatment. An increased incidence of infusion-related reactions (IRRs) was observed at the start of combination treatment in Cycle 2 during the BV infusion leading to 1 dose delay. Premedication with corticosteroids (hydrocortisone 100 mg or equivalent) and antihistamines at Cycles 2-4 was instituted through a protocol amendment. Six pts have completed combination treatment, and all have achieved an objective response (ORR, 100%), with 3 of 6 achieving a complete metabolic response (CmR, 50%). All 6 pts have proceeded directly to ASCT. Median number of CD34+ cells collected was 12.9 x106 cells/kg (range, 5-26) in a mean number of 1.7 apheresis sessions (range, 1-2). Adverse events (AEs) for all pts are summarized prior to ASCT. Eighteen of the 23 treated pts (78%) experienced adverse events (AEs). Fifteen pts (65%) had AEs ≤ Grade 2 in severity and 3 pts (13%) experienced Grade 3 AEs. No pts experienced Grade 4 AEs pre-ASCT. Fatigue was the most common AE occurring in 35% of pts, followed by nausea (26%), rash (22%), dyspnea, myalgia, and pruritus (17% each). One pt experienced a treatment-related serious adverse event (SAE) of dehydration, hypercalcemia, and acute kidney injury. Immune-related adverse events (IrAEs) were experienced by 3 pts; 2 pts who experienced Grade 1 rash treated with topical steroids, and 1 pt who experienced Grade 1 hypothyroidism. No pts have discontinued treatment prematurely. In addition to Reed-Sternberg cells, CD30 is expressed on activated T cells. Preliminary biomarker data indicate a BV-induced decrease in the percentage of CD4+ T regulatory (Treg) cells at C1D8, with no decrease in proliferating CD8+ T cells, and no significant decrease observed in the percentage of CD4+ Th1 cells compared to baseline for 5 of 6 pts (83%). Nivolumab induced a robust expansion of T cells at C1D15. Conclusions Early data suggest the combination of BV and nivolumab is an active and well-tolerated salvage therapy in pts with R/R HL. While an elevated incidence of IRRs has been observed, toxicities with this regimen appear to be tolerable overall. The preliminary antitumor activity suggests this combination may be a promising option for R/R HL pts. Updated results will be shared at the time of presentation. Disclosures Herrera: Pharmacyclics: Research Funding; Merck: Research Funding; Immune Design: Research Funding; Genentech: Research Funding; Adaptive Biotechnologies: Research Funding; Seattle Genetics: Research Funding. Bartlett:Gilead: Consultancy. Moskowitz:BMS: Honoraria, Research Funding; Seattle Genetics: Honoraria, Research Funding. Feldman:Abbvie/Pharmacyclics/Janssen: Speakers Bureau; Seattle Genetics: Consultancy, Research Funding, Speakers Bureau; Celgene: Consultancy, Speakers Bureau. LaCasce:Seattle Genetics: Research Funding; Forty Seven Inc.: Consultancy. Ansell:Bristol Myers Squibb: Research Funding; Seattle Genetics: Research Funding; Celldex: Research Funding; Affimed: Research Funding. Fenton:Seattle Genetics: Employment, Equity Ownership. Kato:Bristol-Myers Squibb: Employment. Fong:Seattle Genetics: Employment, Equity Ownership.