Ansell, Stephen M.

Abstract Background: Vitamin D insufficiency (VDI) has been associated with inferior outcomes in patients with follicular lymphoma (FL) treated with chemotherapy and an anti-CD20 monoclonal antibody (immunochemotherapy; IC), but whether this association holds for other FL treatment strategies is not known. Furthermore, the subset of FL patients who experience clinical failure (progression, treatment failure) within 12 months of diagnosis have an inferior outcome compared to those achieving event-free status at 12 months (EFS12). We tested the hypothesis that VDI is predictive of early clinical failure (failure to achieve EFS12), overall survival (OS), and lymphoma-specific survival (LSS) among FL patients overall and in subgroups who were initially observed, treated with IC, rituximab monotherapy, or other therapies. Methods: We evaluated this hypothesis in a prospective cohort study of 642 newly diagnosed patients with grade 1-3a FL enrolled from 2002-2012 in the Molecular Epidemiology Resource of the Iowa/Mayo Lymphoma SPORE. Serum 25-hydroxyvitamin D [25(OH)D] was measured by liquid chromatography-tandem mass spectroscopy, and VDI was defined as serum total 25(OH)D <20 ng/mL (per Institute of Medicine criteria) determined within 120 days of diagnosis. We used logistic regression to estimate Odds Ratios (ORs) and 95% confidence intervals (CIs) and Cox regression to estimate hazard ratios (HRs) and 95% CIs. We adjusted for FLIPI, body mass index, and month of blood draw; for the full cohort, we additionally adjusted for treatment. Results: The mean age at diagnosis was 60 years (range 23-93); 19% of patients had VDI. The median follow-up period was 59 months (range 1-144), with 297 events and 78 deaths (42 due to lymphoma). Treatment included IC (N=252), observation (N=218), rituximab monotherapy (N=76), or other (N=96). OS and EFS curves are shown in figures 1 and 2. In the full cohort, VDI was associated with inferior EFS12 (OR=2.05; 95% CI 1.18-3.54), OS (HR=2.35; 95% CI 1.37-4.02), and LSS (HR=2.97; 95% CI 1.52-5.80). In the IC subset, VDI was associated with inferior EFS12 (OR=3.00; 95% CI 1.26-7.13), OS (HR=2.86; 95% CI 1.39-5.85), and LSS (HR=2.96; 95% CI 1.29-6.79). VDI was associated with inferior OS in patients who were observed (HR=2.25; 95% CI 1.20-6.76) or received other therapies (HR=3.06; 95% CI 1.01-9.24). VDI was positively but not statistically significantly associated with inferior EFS12 in the patients who were observed (OR=1.71; 95% CI 0.70-4.17) or received other therapies (OR=2.31; 95% CI 0.41-13.07), with low power for these associations; LSS could not be estimated due to lack of deaths. There were too few events (N=10) and deaths (N=5) in the R-monotherapy group for analysis. Conclusions: We confirm previous findings that vitamin D insufficiency is associated with adverse long-term prognosis among patients with FL treated with IC, and extend these findings to patients who are initially observed or treated with other therapies. For the first time, we observed an association of vitamin D insufficiency with early clinical failure, suggesting a potentially modifiable factor to address in this subset of patients with poor outcomes. Whether treating VDI improves outcomes in FL warrants assessment. Disclosures Ansell: BMS, Seattle Genetics, Merck, Celldex and Affimed: Research Funding. Nowakowski:Celgene: Research Funding; Morphosys: Research Funding; Bayer: Consultancy, Research Funding.

Abstract Introduction: REGN1979 is a hinge-stabilized CD20xCD3bispecific full-length antibody (Ab) based on an IgG4isotype modified to reduce Fc binding. It is designed to bind T cells (via CD3) and CD20-expressing cells. Cross-linking results in specific, local T cell activation and engagement ofcytolytic functions, independent of T cell receptor mediated recognition. This mechanism of action (MOA) is distinct from approved anti-CD20 Abs, and may provide additional therapeutic benefit. This report describes safety and clinical outcomes in 25 patients (pts) treated with REGN1979. Methods: The study uses a 3+3 design to assess safety, pharmacokinetics (PK), pharmacodynamics (PD), and activity of REGN1979 inpts with NHL and CLL, in separate dose escalation cohorts. REGN1979 is administered IV over 1-4 hours, weekly (QW) for 4 doses followed by every 4 weeks (Q4W) for 5 doses. Each dose level (DL) consists of an initial starting dose followed by a higher (step-up) dose.Pts with either progressive disease (PD) after initial response or suboptimal initial response could be retreated. Results: As of clinical cut-off, 25pts had been enrolled and treated with REGN1979 at flat doses ranging from 0.03 - 3.0 mg: 20pts with NHLand 5pts with CLL. NHL subtypes included DLBCL (n=12), FL (n=6), and MCL (n=2). Allpts hada medianof3 (range 1-7) prior regimens, and received a median of 5 (range 2-9) doses of REGN1979. Sixpts remained on initial treatment, 3pts completed treatment, and 16pts discontinued treatment (14 for PD; 2 subject decision). Of 4pts who entered retreatment, 2pts remained ongoing. The most common treatment-related treatment-emergent AEs (TR-TEAEs) were pyrexia (56%), infusionrelated reaction (IRR) (40%), chills (36%), cytokine release syndrome (CRS) (28%), fatigue (24%), tachycardia (24%), hypomagnesaemia (20%) and hypotension (20%). Grade >= 3 TR-TEAEs occurred in 8 pts(32%): IRR (12%), CRS (8%), hypotension (8%), and pyrexia, tachycardia, dyspnea, anemia, hypoxia, hypertension, tachypnea, transaminases increased, and tumor pain each in 1 pt(4%). All were grade 3 with the exception of 1 ptwith grade 4 hypotension. There were no protocol-defined DLTs, nor grade 5 TEAE. No ptsdiscontinued REGN1979 due to TR-TEAE. IRR and CRS events were most commonly reported with the first administration of both initial and step-up dose with incidence and severity decreasing with increasing exposure. Tenptsreported at least one TR-SAE: CRS (24%), IRR (20%), and increased AST and tumor pain, each in 1pt(4%). Threeptswith aggressive lymphoma who discontinued REGN1979 due to PD died of their disease within 30 days of their last dose. Notably, modifications to pre-medication(s) and drug administration instructions have improved tolerability (fewer and less severe IRR/CRS). No clinically significant CNS TEAEs have been observed. CT-based (Cheson, 2007) anti-tumor activity was observed in 11 ptswith NHL: PR [n=4,median duration of 50d];SD [n=7, median duration of >196d]. The overall response rate (ORR) in NHL ptsacross DLs was 20%. In 2 highest dose levels, ORR was 27% (Fig 1). Of the 14pts evaluated by PET, 4pts had a partial metabolic response, withmedian duration of 244d perLugano Criteria. Twopts with CLL attained SD as best overall response. PK: REGN1979 concentrations in serum increased with increasing DL and were variable across pts. Variability was less at higher DLs and also decreased over time during therapy. At DLs tested, REGN1979 concentrations did not notably increase over time during treatment. PD/Cytokines: At the lowest dose tested, 0.03 mg, transient B-cell depletion was observed inpts with measurable circulating B cells.Samples from 12pts were available for cytokine analysis. Interim analysis indicates REGN1979 induces cytokine release as expected based on MOA. An increase in IL-6, IL-10 and to lesser extent IFN-γ was observed. The magnitude of cytokine response generally correlated with symptomatic IRR/CRS. Conclusion: REGN1979 demonstrated an acceptable safety profile at flat doses of 0.03 - 3.0 mg (< 1% of rituximab dose) inpts with NHL and CLL. Most TEAEs were associated with IRR/CRS, and were managed with supportive therapy and modification to REGN1979 administration. No clinically significant neurological toxicity was observed. Preliminary antitumor activity demonstrates increased activity at higher doses. Dose escalation and treatment schedule optimization continue. Disclosures Brown: Acetylon, Gilead: Research Funding; Celgene, Roche/Genentech, Gilead, Infinity, Janssen, Pharmacyclics, ProNai, Sun BioPharma: Consultancy. Arnason:Gilead: Consultancy. O'Brien:Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria. Chavez:Janssen: Speakers Bureau. Ansell:BMS, Seattle Genetics, Merck, Celldex and Affimed: Research Funding. Topp:Amgen: Consultancy, Honoraria, Other: travel, Speakers Bureau; Roche: Honoraria, Other: travel; Boehringer: Consultancy, Other: Travel, Research Funding; Jazz: Consultancy; Pfizer: Consultancy, Other: Travel. Adriaens:Regeneron Pharmaceuticals Inc.: Employment, Equity Ownership. Ufkin:Regeneron Pharmaceuticals Inc.: Employment, Equity Ownership. Kostic:Regeneron Pharmaceuticals Inc.: Employment, Equity Ownership. Paccaly:Regeneron Pharmaceuticals Inc.: Employment, Equity Ownership. Gao:Regeneron Pharmaceuticals Inc: Employment, Equity Ownership. Trail:Regeneron Pharmaceuticals Inc: Employment, Equity Ownership. Lowy:Regeneron Pharmaceuticals Inc: Employment, Equity Ownership. Brownstein:Regeneron Pharmaceuticals Inc: Employment, Equity Ownership.

Abstract Background Recent genome wide association studies (GWAS) of Hodgkin lymphoma (HL) have identified several associations at both HLA and non-HLA loci. However, much of HL heritability remains unexplained. Methods To identify novel risk loci, we performed a meta-analysis of 3 HL GWAS including a total of 1,810 cases and 7,879 controls. Results were replicated in an independent set of 1,163 cases and 2,580 controls, for a total of 3,097 and 11,097 cases and controls combined, respectively. participants in discovery and replication stages were of European descent. quality control and imputation we conducted a meta-analysis addressing 1,004,829 variants (λ= 1.10, λ1000= 1.03). Associations between SNP genotypes and HL risk were evaluated under a log-additive model of inheritance adjusting for sex, study center and significant principal components to control for population stratification. We performed an analysis with all HL cases and then conducted stratified analyses by histological subtype (classical, nodular sclerosis and mixed cellularity), age at diagnosis (nodular sclerosis among those diagnosed at 15- 35 years in all studies, and those diagnosed at 35 and older years in the European Study only) and EBV tumor status (negative and positive). We then used a bioinformatic approach (FunciSNP) to identify potential functional variants associated with HD risk correlated with risk loci of interest. We extracted publically available ENCODE data on biofeatures to identify potential functional motifs associated with the index SNP or correlated SNPs. Finally, we measured expression levels of the two alternative mRNA transcripts in lymphoblastoid cell lines (LCLs) from 49 post-therapy HL patients and 25 unaffected controls. RT-PCR was carried out in triplicate. Relative expression levels were calculated relative to TBP as housekeeping gene. Linear models were used to assess correlation between genotype and TCF3expression levels. Results The meta-analysis identified a novel susceptibility variant at chromosome 19p13.3 (rs1860661) associated with HL risk (Odds Ratio [OR]= 0.78, P=2.0*10-8, I2=0%). variant is located in intron 2 of TCF3 (also known as E2A), a regulator of B- and T-cell lineage commitment. was also significantly associated with HL (OR= 0.85, P=0.002) in the replication series of 1,281 cases and 3,218 controls. the combined analysis consisting of the discovery and replication sets, rs1860661was strongly associated with HL (OR=0.81,=3.5*10-10), with no evidence of heterogeneity between contributing studies (Phom=0.41, I2=0%). The number of G alleles defined by rs1860661 was significantly associated with a reduced risk of each HL subtype except EBV positive HL. rs1860661 and two correlated SNPs, rs10413888 (r2=0.90) and rs8103453 (r2=0.89) identified by FunciSNP analysis map in or near marks of open chromatin and in DNAse hypersensitivity sites in TCF3 in CD20+ B cell lines., the protective minor alleles of these SNPs as defined by the G-G-G haplotype map to the binding sites for ZBTB7a (rs10413888 and rs1860661) and (rs8103453) transcription factors, likely improving the binding efficiency to the sites which may result in increased transcription rates of TCF3. TCF3 is encoded by two alternative transcripts (E12 and E47). Higher expression levels of TCF3-E47, whose transcription start site is located close to rs1860661, was associated with the rs1860661-G allele in controls (P=0.02), but not in HL patients (P=0.22). Conclusion/Discussion TCF3 is essential for the commitment of lymphoid progenitors to both B-cell and T-cell lineage development. A molecular and phenotypic hallmark of classical HL is the loss of the B-cell phenotype in HRS cells, including lack of demonstrable B-cell receptor and most B-cell specific markers such as CD19 or CD20. HRS cells have a low level of TCF3, particularly homodimers of the isoform E47, due to expression of the ABF-1 and ID2 inhibitors that bind to TCF3. Thus, higher TCF3 levels in HRS precursor cells may lead to enhanced retention of the B cell phenotype, thereby conferring a protective effect. These data suggest a link between the 19p13.3 locus including TCF3 and HL risk, indicating that TCF3 could be relevant to HL etiology and pathogenesis. Disclosures: Link: Genentech: Consultancy; Millenium: Consultancy; Pharmacyclics: Consultancy; Spectrum: Consultancy.

Abstract Background Long-term outcomes from autologous stem cell transplant (ASCT) in patients (pts) with relapsed/refractory (R/R) Hodgkin lymphoma (HL) are significantly better in patients who achieve a complete remission (CR) from salvage chemotherapy prior to ASCT. However, standard salvage therapy produces variable CR rates (19%-60%) and is associated with significant toxicity. Brentuximab vedotin and bendamustine are highly active when administered as single agents to pts with R/R HL (34% and 33% CR rates, respectively) and have manageable safety profiles. 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 primary refractory disease or in first relapse (ClinicalTrials.gov #NCT01874054). Methods Pts received an outpatient IV infusion of 1.8 mg/kg brentuximab vedotin on Day 1 with bendamustine on Days 1 and 2 of 3-week cycles for up to 6 cycles. Pts could undergo ASCT any time after Cycle 2 and post-transplant resume treatment with brentuximab vedotin as monotherapy for up to 16 total doses. Phase 1 was designed to determine the recommended dose of bendamustine, with an initial dose of 90 mg/m2 and a de-escalation scheme to be implemented if it exceeded the maximum tolerated dose. 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. Enrollment is complete and long-term follow-up for PFS and OS continues. Results Fifty-five pts (56% female) with a median age of 36 yrs (range, 19-79) were enrolled. Fifty-one percent of pts had relapsed disease and 49% of pts had primary refractory disease after frontline therapy. A median of 13.8 mos (range, 3-98) had elapsed since initial diagnosis. No dose-limiting toxicities 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 and a median of 9 cycles (range, 1-14) of single-agent brentuximab vedotin. The main toxicity observed with the combination was infusion-related reactions (56% overall). The most common symptoms (≥10%) were pyrexia (26%), chills (20%), dyspnea and nausea (15% each), flushing (13%), and hypotension (11%). Premedication with corticosteroids and antihistamines was instituted with a protocol amendment and appeared effective. Before the amendment, 6 pts (24% of treated pts) discontinued treatment prematurely because of IRRs; post-amendment, IRRs led to treatment discontinuation for 2 pts (7%). The CR rate of the combination was 74% (39/53 pts evaluable for response) and the overall objective response rate (CR and partial remission) was 93% (49/53 pts). The CR rate was 64% and 84% for refractory and relapsed pts, respectively. Stem cell collection after first-line mobilization (G-CSF± plerixafor) was successful in 93% of pts (37/40). Median number of CD34+ cells collected was 4.1 x106 (Q1, Q3: 3.0, 5.4) in a median of 2 (range, 1-5) apheresis sessions. Median time to neutrophil and platelet engraftment was 11 days (range, 9-21) and 13 days (range, 9-39), respectively. Pts have been followed for a median of approximately 1 year from first dose (median = 418 days; range, 118-635) and approximately 10 mos (314 days; range, 13-553) from ASCT. To date, 12 progression events have been observed: 7 in the 40 pts who underwent transplant and 5 in the 13 pts who did not undergo transplant. The estimated 12-mos PFS is 80% for both the transplanted population (95% CI: 70%, 90%) and the overall population (95% CI: 60%, 90%). Three of the 12 progression events were deaths; 2 pts died from progression of their HL and 1 pt died from septic shock after transplant. 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 induced a very high CR rate that compares favorably with historical data. The regimen has a manageable safety profile, with the most significant side effect being IRRs that can be successfully managed by premedication. The estimated 12-mos PFS rate of 80% demonstrates response durability, making the combination a promising salvage regimen for pts with HL in the first relapse setting. Progression-Free Survival Figure 1. Figure 1. Disclosures 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. This study evaluates brentuximab vedotin in HL patients with primary refractory disease or in first relapse. . Sawas:Seattle Genetics, Inc.: Research Funding. Agura:Seattle Genetics, Inc.: Research Funding. Matous:Takeda Pharmaceuticals International Co.: Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Seattle Genetics, Inc.: Research Funding, Speakers Bureau. Ansell:Bristol-Myers Squibb: Research Funding; Celldex: Research Funding. Crosswell:KIYATEC (employment); Gilead (common stock ownership and research funding): Employment, Equity Ownership, Research Funding. Islas-Ohlmayer:Seattle Genetics, Inc.: Research Funding. Behler:Seattle Genetics, Inc.: Research Funding; Onyx Pharmaceuticals: Speakers Bureau. Cheung:Seattle Genetics, Inc.: Research Funding. Forero-Torres:Seattle Genetics, Inc.: Research Funding. Vose:Seattle Genetics, Inc.: Honoraria, Research Funding. Josephson:Seattle Genetics, Inc.: Employment, Equity Ownership. Advani:Seattle Genetics, Inc.: Research Funding; Genetech: Consultancy.

Background: The DIAL study is testing the efficacy of dual immunomodulation in patients with advanced aggressive B cell non-Hodgkin lymphoma (B-NHL). Sponsored by the Cancer Therapy Evaluation Program (CTEP), the trial combines the use of a programmed cell death protein 1 (PD-1) inhibitor (nivolumab) with an agonist of the CD27 receptor (varlilumab) in a randomized phase 2 design. CD27, a co-stimulatory receptor, regulates T cell activation in the context of T cell receptor (TCR) engagement through interaction with CD70. T cell exhaustion plays a major role in immune evasion in B-NHL. Varlilumab is an agonistic IgG1 monoclonal antibody that recognizes CD27 leading to prevention or reversal of exhaustion in pre-clinical models. Varlilumab also demonstrates direct anti-tumoral activity in xenograft models of human lymphoma cell lines via antibody-dependent cell-mediated cytotoxicity. Phase 1 data supports the safety and tolerability of single-agent varlilumab in advanced hematologic malignancies (NCT01460134). We hypothesize that CD27 activation synergizes with PD-1 inhibition resulting in a superior anti-lymphoma effect compared to PD-1 blockade alone. The study will also evaluate the effect of these agents on tumor and immune cells using immunohistochemistry (IHC), mass cytometry (CyTOF), multiplex ELISA, imaging mass cytometry (IMC), and whole exome sequencing. Methods: The trial is enrolling patients with advanced aggressive B-NHL. Standard inclusion criteria and prior treatment with at least 2 lines of standard therapy are required. Prior autologous stem cell transplant and/or chimeric antigen receptor (CAR) T cell therapy is allowed. Patients with active CNS disease are excluded. Eligible patients are randomized to treatment with single-agent nivolumab (group 1) or dual immunotherapy with nivolumab and varlilumab. Group 1 is allowed to cross-over at the time of progression. Nivolumab will be administered intravenously (IV) every 2 weeks (240 mg) for 4 months followed by monthly dosing thereafter (480 mg). Varlilumab will be given IV every 4 weeks (3 mg/kg). Response assessment will be done by PET-CT scan every 12 weeks. Primary outcome is overall response rate (ORR) according to the LYRIC criteria. The trial will enroll 48 patients per arm, allowing 80% power to detect at least 20% increase in ORR in the experimental arm (group 2) assuming a 25% ORR in the control arm (group 1). The trial is registered (NCT03038672) and open to participation to members of the Experimental Therapeutics Clinical Trials Network (ETCTN) and Early Drug Development Opportunity Program (EDDOP). Figure Disclosures Tun: BMS: Research Funding; Celgene: Research Funding; Curis: Research Funding; TG Therapeutics: Research Funding; Mundi-pharma: Research Funding; DTRM Biopharma: Research Funding. Bartlett:Pharmacyclics: Research Funding; Merck: Research Funding; Incyte: Research Funding; ADC Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Research Funding; Millennium: Research Funding; Kite Pharma: Research Funding; Janssen: Research Funding; Immune Design: Research Funding; Affimed: Research Funding; Autolus: Research Funding; Bristol-Myers Squibb: Research Funding; Celgene: Research Funding; Forty Seven: Research Funding; Genentech, Inc.: Research Funding; Gilead: Research Funding. Kline:Merck: Honoraria; Merck: Research Funding. Awan:Janssen: Consultancy; Gilead: Consultancy; Sunesis: Consultancy; Genentech: Consultancy; Abbvie: Consultancy, Speakers Bureau; Pharmacyclics: Consultancy, Research Funding; AstraZeneca: Consultancy, Speakers Bureau. Lazaryan:Kadmon: Consultancy. Ansell:Affimed: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Affimed: Research Funding; Affimed: Research Funding; Affimed: Research Funding; LAM Therapeutics: Research Funding; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; LAM Therapeutics: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Regeneron: Research Funding; Regeneron: Research Funding; Regeneron: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Trillium: Research Funding; Trillium: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Trillium: Research Funding; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Mayo Clinic Rochester: Employment; Trillium: Research Funding; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Bristol-Myers Squibb: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Trillium: Research Funding. Diefenbach:Bristol-Myers Squibb: Consultancy, Research Funding; Denovo: Research Funding; Genentech: Consultancy, Research Funding; Incyte: Research Funding; LAM Therapeutics: Research Funding; MEI: Research Funding; Merck: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Millenium/Takeda: Research Funding; Trillium: Research Funding.

BACKGROUND: Angioimmunoblastic T cell lymphoma (AITL) has a unique histological phenotype with a relatively small number of malignant T-cells and an extensive infiltrate of normal cells including T-cells, B-cells, NK cells and FDCs. The malignant cell has a T follicular helper (Tfh) cell phenotype with increased expression of immune checkpoint molecules including PD-1 and ICOS. With the routine use of antibodies targeting immune checkpoint molecules, clinical results in limited numbers of AITL patients have thus far been mixed with some responding patients but also some who rapidly progress. Because both malignant T-cells and normal T-cells in AITL may be PD-1 positive, we conducted a study to compare the phenotype of normal T-cells and malignant T-cells within the tumor microenvironment. We also evaluated whether soluble immune checkpoint molecules in the peripheral blood differed between AITLs, controls, and other PTCL subgroups. METHODS: We designed a novel CyTOF antibody (Ab) panel comprised of 37 markers to identify and characterize cells of T, B, NK, macrophage and FDC lineages within a cohort of biopsy specimens from 6 AITL patients compared to 6 normal controls (2 LN, 4 tonsil). Soluble immune receptors and ligands were then measured by multiplex ELISA on peripheral blood from 8 AITLs, 5 controls, and 32 additional samples from PTCL subtypes including PTCL-NOS, ALCL and CTCL. RESULTS: Malignant T-cells in AITL specimens could clearly be identified by viSNE mapping based on CyTOF expression of CD4, CD5, BCL6, CD10 (variable), CXCR5 (variable), PD-1 and ICOS. Aberrant loss of CD3 and CD7 on malignant T-cells was commonly seen. Expression of other immune checkpoint molecules was assessed. Malignant cells expressed high levels of TIGIT and moderate levels of CD27, but malignant T-cell populations were negative for expression of TIM3, LAG3, and CTLA-4. A substantial proportion of normal T-cells also expressed immune checkpoint molecules including PD-1 and CD27, and a subset of these cells also expressed TIGIT and ICOS. A small minority of normal T-cells expressed TIM3, LAG3, and CTLA-4. As others have described, the normal Tfh cell population had an immunophenotype that was otherwise relatively similar to the malignant population, but distinguishable via viSNE mapping with our CyTOF Ab panel. Expression of PD-L1 could be detected on NK-cells, macrophages, and a few select populations of normal T cells, but not on B-cells or FDCs. Malignant T-cells did not express PD-L1. Due to the potential importance of immune checkpoint molecules in this disease, we then measured soluble checkpoint receptors and ligands in the serum. Soluble PD-1 was significantly increased in the peripheral blood of AITL when compared to normal controls (average 2637 pg/mL (SE = 512.1) in AITL vs 57.87 (SE = 16.88) in controls). Similarly, soluble PD-L1 was significantly increased in AITL compared to normal controls (13.8 (SE = 10.5) in AITL vs 0.94 (SE = 0.25) in controls). CONCLUSIONS: Malignant T-cells in AITL have a unique phenotype which was able to be reliably identified through use of viSNE mapping with our CyTOF Ab panel. Furthermore, malignant T-cells were found to consistently express additional immune regulatory molecules beyond PD-1 and ICOS, including TIGIT and CD27. However, a substantial subset of normal T-cells have a very similar phenotype suggesting that activation of T-cells in this disease will likely stimulate both normal and malignant T-cells. This may explain the rapid disease progression seen in a subset of AITL patients treated with PD-1 blockade. Furthermore, soluble PD-1 is significantly increased in the serum of AITL patients and may explain the overall lack of clinical efficacy of anti-PD-1 antibodies in treating AITL. Disclosures Cerhan: NanoString: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding. Ansell:LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Trillium: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Bristol-Myers Squibb: Research Funding; Seattle Genetics: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Affimed: Research Funding; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; Regeneron: Research Funding; Affimed: Research Funding; Affimed: Research Funding; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; Affimed: Research Funding; Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Affimed: Research Funding; Trillium: Research Funding; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Trillium: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; LAM Therapeutics: Research Funding.

BACKGROUND: Axi-cel is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy that is approved for treatment of relapsed/refractory (R/R) large B-cell lymphoma and is associated with high response rates and durable remissions. Recent data show that axi-cel is effective across various adverse prognostic features, namely cell of origin, disease bulkiness, and extranodal disease, among others. Hypoalbuminemia is a known adverse prognostic factor in lymphomas. It is unknown if axi-cel overcomes the adverse prognostic feature of hypoalbuminemia in R/R large B-cell or transformed follicular lymphoma. METHODS: We conducted a retrospective analysis of patients treated with axi-cel across three Mayo Clinic campuses (Rochester, Jacksonville, and Phoenix) from 06/01/2018 until 04/01/2019. The primary objective of this analysis was to assess the impact of hypoalbuminemia (defined at day 0, prior to infusion) on outcome after axi-cel therapy. RESULTS: A total of 50 (male=37, 74%) patients (pts), median age of 53 (26-67) years received axi-cel. The median number of prior lines of therapy was 3 (2-8) (Table 1). Two pts had no available serum albumin levels at time of axi-cel infusion. Seven (15%) of 48 pts had serum albumin levels lower than 3.5 g/dL (median= 3.3 g/dL (range 2.6-3.4)) and the median follow up of survivors was 7.6 (1.9-14.3) months. The best overall response rate (ORR) and complete remission (CR) rates in these pts were 57% and 57%, respectively. One (14%) patient had stable disease and 2 (29%) had disease progression. The median overall survival (OS) for pts with hypoalbuminemia was not reached. On the other hand, 41 (85%) pts had a normal serum albumin level (median=4.0 (range 3.5-5.1) g/dL) and the median follow up for survivors was 6.3 months. The best objective response rate (ORR) and complete remission (CR) rates in these pts were 82% and 44%, respectively. The median OS for pts with normal serum albumin was 14 (95%CI=6.3-29.6) months. There was no significant difference at 6-months and 1-year OS between pts with hypoalbuminemia vs. those with normal baseline serum albumin levels [6-month=100% vs. 79%(95%CI=64-93%); 1-year (100% vs. 54% (95%CI=26-82%), p=0.17] (Figure 1). All grades cytokine release syndrome (CRS) was diagnosed in all 7 pts with hypoalbuminemia (100%) and in 38 of 41 (92%) pts without hypoalbuminemia. There was no difference in the median duration of CRS between pts with or without hypoalbuminemia [6 (range 1-11) days vs 5 (range 1-19) days, p=0.89]. Neurotoxicity (all grades) was observed in 5 (71%) pts with hypoalbuminemia compared 26 (63%) with normal albumin levels. There was no statistically significant difference in median duration of neurotoxicity between pts with hypoalbuminemia and those with normal baseline albumin levels [9 (range 1-10) days vs. 3 (range 0-25) days, p= 0.72]. CONCLUSIONS: Hypoalbuminemia does not have a significant impact on the outcomes of axi-cel therapy, including the incidence of CRS or neurotoxicity. These results need to be validated in a large collaborative multicenter study. Further investigation is needed to assess the prognostic impact of severe hypoalbuminemia (<3g/dL) on axi-cel therapy. Disclosures Ansell: Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Trillium: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Affimed: Research Funding; LAM Therapeutics: Research Funding; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Affimed: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Trillium: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Mayo Clinic Rochester: Employment; Trillium: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Bristol-Myers Squibb: Research Funding; Seattle Genetics: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Affimed: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Affimed: Research Funding. Bennani:Seattle Genetics: Other: Advisory board; Kite Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Adicet Bio: Other: Advisory board; Seattle Genetics: Other: Advisory board; Purdue Pharma: Other: Advisory board; Adicet Bio: Other: Advisory board; Purdue Pharma: Other: Advisory board; Purdue Pharma: Other: Advisory board; Adicet Bio: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board. Paludo:Verily Life Sciences: Research Funding; Celgene: Research Funding; Verily Life Sciences: Research Funding; Celgene: Research Funding. Tun:DTRM Biopharma: Research Funding; Mundi-pharma: Research Funding; BMS: Research Funding; Celgene: Research Funding; Curis: Research Funding; TG Therapeutics: Research Funding. Foran:Agios: Honoraria, Research Funding. Kharfan-Dabaja:Daiichi Sankyo: Consultancy; Pharmacyclics: Consultancy.

Introduction: Current classifications of low-grade B-cell lymphomas (LGL), including splenic marginal zone lymphomas (SMZL), nodal marginal zone lymphomas (NMZL), and Lymphoplasmacytic lymphomas (LPL) are based on a mixture of clinical features and morphologic, immunophenotypic, and genetic findings from the tumor biopsy specimen. While this approach to classification makes pathologic diagnosis more precise, the corresponding clinical impact for the timing and choice of treatment is limited, and differentiating between cases can be challenging. Although LGL are considered indolent and the 10-year overall survival (OS) is about 80%, 70% of cases will eventually require treatment and approximately 30% of patients display a more aggressive phenotype and have a poor prognosis. Consequently, further investigations into the driving genetic, biological, and immune mechanisms of LGL are essential for early identification of high-risk patients and design of personalized treatments. Materials and Methods: RNA-seq was performed on 63 newly diagnosed LGL patient samples from the Mayo Clinic/University of Iowa Lymphoma SPORE: SMZL (N=48), NMZL (N=6), LPL (N=5), MALT (N=2), and BCL (N=2) as well as 5 normal memory B cell controls (CD19+CD27+). For identification of biologic clusters, filtered RNA-seq data was analyzed using the Non-negative Matrix Factorization (NMF) clustering tool from the Broad Institute against the normal samples. Each cluster was analyzed for differential gene expression. This analysis generated cluster-specific T values for each gene. Genes that were significantly associated with a cluster (FDR<0.05) were analyzed for genetic ontology. Cibersort was used to deconvolute the tumor microenvironment (TME). We performed whole exome sequencing (WES) analyses on 60/63 matched LGL to characterize mutations and copy number alterations. Results: WES revealed the presence of previously reported mutations in genes such as MYD88, SPEN, NOTCH, and KLF2 as well as copy number alterations 7q31.2, BCL6, TNFAIP3, and BCL2. NMF clustering of RNA-seq data resulted in a best fit of 5 clusters, named LGL1 through LGL4 and "Normals". Pathologic subtypes were not exclusive to a specific cluster. Differential RNA expression analysis resulted in gene sets that were differentially expressed in each cluster. A cluster signature of the top 1% of associated genes (N=94) was created for each. LGL1 genes were associated with higher BCR signaling. LGL2 was characterized by regulatory dysfunction, particularly concerning mitochondrial integrity. LGL3 genes were associated with high TME and NOTCH and STAT signaling components. Specifically, LGL3 was associated with high CD8+ T-cell and M2 macrophage TME presence. LGL4 was distinguished by the presence of aggressive genetic programs related to B-cell activation such as NF-kB and IRF4. Consequently, LGL4 patients had significantly poorer rates of event-free survival (EFS) (P=0.029) and OS (P=0.006) when compared against the other groups. The top 1% gene signature (N=94) was next validated against an independent cohort of 84 LGL samples with gene expression data (SMZL [N=34], NZML [N=24], and LPL [N=24]). A similar cluster pattern emerged, with pathological subtypes distributing across LGL classifications based on respective transcriptomic signatures. Association of DNA variants within each cluster was also analyzed, but due to the low frequency of genomic variants detected in LGL, nothing was significantly associated. However, we did see an enrichment of BCL2, BCL6, and TNFAIP3 alterations in LGL4 and an overall lower driver gene mutation frequency in LGL2. Conclusions: Gaining a greater understanding of LGL based on their genetic, biologic, and immune profiles will establish a valuable platform for clinicians to identify high-risk cases and make better therapeutic decisions. Using a large cohort of well-annotated cases we identify novel clusters of LGL that present unique genomic and clinical profiles. Our study lays the groundwork for a precision therapy approach in LGL in which DNA or RNA profiles can be used to identify patients early in treatment who may not benefit from the current standard of care and who would benefit from closer monitoring and targeted agents. Disclosures Anagnostou: American Society of Hematology, Mayo Clinic/Iowa Lymphoma SPORE, Mayo Clinic Immune Monitoring Core, Mayo Clinic Hematology Small Grant: Research Funding. Ansell:Bristol-Myers Squibb: Research Funding; Regeneron: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; LAM Therapeutics: Research Funding; Affimed: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; Affimed: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Trillium: Research Funding; Bristol-Myers Squibb: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; LAM Therapeutics: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Trillium: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Affimed: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; LAM Therapeutics: Research Funding; Affimed: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; LAM Therapeutics: Research Funding; Mayo Clinic Rochester: Employment. Cerhan:Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; NanoString: Research Funding. Novak:Celgene Coorperation: Research Funding.

Background: Central nervous system (CNS) involvement by peripheral T cell lymphoma (PTCL) is a rare condition. Among primary CNS lymphomas, only 2% are secondary to PTCL, while the risk of CNS relapse in all cases of PTCL is estimated at 2% to 6%. Little is known about the presentation and outcomes of PTCL patients with CNS involvement given the rarity of this entity. In this study, we describe patient characteristics, histology, and clinical course of patients with CNS involvement by PTCL. Methods: The Mayo Clinic Lymphoma Database was used to identify PTCL patients with primary or secondary CNS involvement seen at our institution between 2000 and 2018. A total of 12 patients were identified and their medical records were reviewed for patient and disease characteristics, CNS-directed treatment modality, and outcomes. The Kaplan-Meier method was used for time-to-event analysis. Results: The median age at CNS diagnosis was 63 years (range 41 to 76) and 11 (93%) patients were male. The histological diagnoses were PTCL, NOS in 9 (75%) patients, enteropathy-associated T-cell lymphoma in 2 (17%) patients, and angioimmunoblastic T-cell lymphoma in 1 (8%) patient. Five patients presented with primary T-cell CNS lymphoma (all with a PTCL, NOS histology), while the remaining 7 (58%) patients also had systemic involvement. All patients presented with neurologic symptoms at the time of CNS involvement diagnosis including: focal motor deficits in 6 patients (unilateral upper extremity weakness, gait impairments, and hemiparesis), cognitive decline in 5 patients (memory impairments, reduced attention, and confusion), headache in 4 patients, and seizure in 3 patients. The CNS disease location included the brain parenchyma in 9 (75%) patients, leptomeninges in 1 (8%) patient, and lumbar plexus in 1 (8%) patient. One patient (8%) had positive CSF finding only without radiologic evidence of involvement. CSF analysis was performed in 11 patients. Elevated protein levels were noted in 3 (27%) patients, malignant cells in 2 (18%), and no clear abnormalities in the remaining 6 (55%) patients. Concomitant bone marrow involvement was seen in only 1 patient. Elevated LDH was seen in 2 patients. The a median LDH was 195 U/L (range 139 to 4,360) The most common CNS-directed therapies were: high-dose methotrexate (MTX)-based regimens in 8 (67%) patients, including high-dose MTX in combination with temozolomide (n=2), or cytarabine and thiotepa (n=2). Intrathecal MTX, temozolomide and dexamethasone, lenalidomide, high-dose steroids, and surgical resection were the treatment modality used for one patient each. At a median follow up of 18 months, eight (75%) out of 12 patients were not alive at the time of last follow up. The median overall survival (OS) from diagnosis was 16 months (95% CI: 2.8-173). The median progression free survival (PFS) from initiation of CNS-directed therapy was 9 months (95% CI: 1.6-33) (figure). Four patients had a PFS longer than 12 months. These 4 patients were treated with: temozolomide/dexamethasone, high-dose MTX, lenalidomide, and high-dose MTX followed by cytarabine/thiothepa. Conclusion: CNS involvement by T-cell lymphoma is a rare complication that carries a poor prognosis. Early onset of neurologic symptoms should trigger prompt investigation of CNS involvement. Despite the short OS and PFS, some patients may achieve a relatively longer disease free interval. Disclosures Bennani: Adicet Bio: Other: Advisory board; Seattle Genetics: Other: Advisory board; Purdue Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Seattle Genetics: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board; Kite Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Adicet Bio: Other: Advisory board; Purdue Pharma: Other: Advisory board; Purdue Pharma: Other: Advisory board; Adicet Bio: Other: Advisory board; Kite Pharma: Other: Advisory board. Cerhan:Celgene: Research Funding; NanoString: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees. Nowakowski:Celgene: Consultancy, Research Funding; Bayer: Consultancy, Research Funding; Curis: Research Funding; F. Hoffmann-La Roche Ltd: Research Funding; Genentech, Inc.: Research Funding; MorphoSys: Consultancy, Research Funding; NanoString: Research Funding; Selvita: Membership on an entity's Board of Directors or advisory committees. Ansell:Mayo Clinic Rochester: Employment; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding. Paludo:Celgene: Research Funding; Verily Life Sciences: Research Funding; Verily Life Sciences: Research Funding; Celgene: Research Funding.

Background: Diffuse large B-cell lymphomas (DLBCL) are a heterogeneous group of aggressive B-cell non-Hodgkin lymphomas (NHL). Primary mediastinal B-cell lymphoma (PMBCL) is often grouped and managed as DLBCL, yet PMBCL is biologically and clinically different. Although about two-third of patients are cured with initial therapy, those who are refractory or progress within the first two years do poorly and will die from their disease. There is an unmet need for effective therapeutic approaches in this patient population. Evasion of the host immune responses is an important mechanism for inducing resistance to cancer therapy. Strategies to block molecular and cellular mediators of cancer induced immunosuppression such as programmed death -1 receptor (PD-1) have been explored. Targeting PD-1 immune checkpoints has the potential to play a major role in cancer therapy by reversing tumor immune escape. Trials using PD-1 blockers in advanced hematological malignancies demonstrated remarkable activity in Hodgkin lymphoma. Unfortunately, results in the DLBCL cohort with nivolumab were marginal and short lived. A phase 1b trial in heavily pre-treated relapsed/refractory (RR) PMBCL using pembrolizumab (a PD-1 blocker) showed that it was safe and active with an ORR of 41%. In recent years, several signaling pathways implicated in DLBCL pathogenesis have been targeted, including the PI3K-AKT-mTOR pathway. Copanlisib, a pan-PI3K inhibitor, with particularly potent PI3K-α/PI3K-δ inhibition, showed activity in both indolent and aggressive NHL, with a safer toxicity profile than the FDA-approved agent idelalisib. In a preclinical DLBCL mouse model, treatment with copanlisib resulted in effective down regulation of tumor‐infiltrating T-regulatory cells (Tregs). In the same model, copanlisib, when combined with a surrogate anti‐mouse PD‐1, showed in vivo responses in 75% vs 0% in the monotherapy groups. These data support the rational for the combination of copanlisib and checkpoint blockade in DLBCL. We developed a phase 2 prospective study with two RR cohorts (DLBCL and PMBCL), treated with the combination of copanlisib and nivolumab. Study Design: copanlisib hydrochloride 60 mg is given IV on days 1, 8 and 15 of cycles 1-8 and days 1 and 15 of subsequent cycles. Nivolumab 240 mg IV is given on days 1 and 15 of cycles 1-8 and 480 mg on day 1 of subsequent cycles. Cycles repeat every 28 days for up to 2 years in the absence of disease progression or unacceptable toxicity. Copanlisib dose will be determined using a safety cohort in 6 patients. The primary outcome is to assess ORR defined as complete and partial responses (CR+PR). Secondary outcomes are to evaluate safety of the combination; to assess progression free survival (PFS), duration of response (DOR), CR rate, and overall survival (OS). Exploratory objectives are to characterize the effects of the copanlisib and nivolumab combination regimen on tumor cells, tumor microenvironment and the immune response in RR DLBCL and PMBCL. We will also do Lymph3CX assay as an integrated biomarker to distinguish between DLBCL and PMBCL. Key inclusion criteria: adult patients with RR DLBCL and PMBCL who have measurable disease with at least one lesion that is >15mm in the longest diameter on cross-sectional imaging; After failure of ASCT or after failure of frontline therapy in subjects who declined or are not ASCT candidates; and have appropriate organ function. Key exclusion criteria: High grade B-cell lymphomas; Active, known or suspected autoimmune disease or patients on any prohibited therapies; History of active CNS involvement or leptomeningeal involvement This study is expected to enroll a maximum of 96 (6 safety cohort, 44 DLBCL and 46 PMBCL) evaluable patients. We anticipate accruing 10 additional patients to account for ineligibility, cancellation, or other reasons. Therefore, the study is expected to accrue a maximum of 106 patients. The largest success proportion where the proposed treatment regimen would be considered ineffective in DLBCL is 25% and 30% in PMBCL. The smallest success proportion that would warrant subsequent studies with the proposed regimen is 45% in DLBCL and 50% in PMBCL. This design has a 90% power with a 1-sided 10% level test. This study is conducted through NCI-CTEP (NCI Protocol #10193; NCT03484819) and is funded by Bayer. The study is to open in fall of 2019 at 11 ECTCN sites, and is available to interested sites to join in. Figure. Disclosures Bennani: Kite Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Purdue Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Purdue Pharma: Other: Advisory board; Adicet Bio: Other: Advisory board; Adicet Bio: Other: Advisory board; Purdue Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board; Kite Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Adicet Bio: Other: Advisory board. Nowakowski:Celgene: Consultancy, Research Funding; Selvita: Membership on an entity's Board of Directors or advisory committees; NanoString: Research Funding; MorphoSys: Consultancy, Research Funding; Genentech, Inc.: Research Funding; F. Hoffmann-La Roche Ltd: Research Funding; Curis: Research Funding; Bayer: Consultancy, Research Funding. Rimsza:NanoSting: Patents & Royalties: Named inventor on a patent licensed to NanoSting [Institution]. Ansell:Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Regeneron: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Regeneron: Research Funding; Mayo Clinic Rochester: Employment; Trillium: Research Funding; LAM Therapeutics: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Seattle Genetics: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Trillium: Research Funding; LAM Therapeutics: Research Funding; Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Affimed: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Affimed: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Affimed: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding.