Search

Background: The rapid global spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains the international public health concern of the decade. Early clinical data suggest that patients (pts) with hematologic malignancies are vulnerable to severe forms of SARS-CoV-2 and have higher mortality rates than the general population. Greater understanding of risk factors and outcomes associated with SARS-CoV-2 in pts with hematologic malignancies is crucial in order to develop individualized risk-benefit analyses to guide care. Herein, we report a cohort study from a Comprehensive Cancer Center evaluating outcomes in pts with hematologic malignancies who developed SARS-CoV-2. Methods: Adult pts at Northwestern Memorial Hospital with a current/prior hematologic malignancy and laboratory-confirmed SARS-CoV-2 infection confirmed by quantitative RT-PCR from nasopharyngeal swabs between March-July, 2020 were identified using electronic health records. Data were collected and analyzed based on epidemiologic, laboratory, and clinical characteristics. Severity of illness was defined by level of care (ambulatory, inpatient), need for advanced respiratory support (high flow nasal cannula, BiPAP, mechanical ventilation), incidence of thrombotic events, incidence of acute kidney injury (AKI), and/or death. Statistical analyses of risk factors, severity, and outcomes were performed. Subgroup analyses based on antineoplastic treatment status and receipt of SARS-CoV-2 -directed therapy were made. Active cancer treatment was defined as antineoplastic therapy within 12 months of SARS-CoV-2 diagnosis. Results: Demographic (Table 1) and clinical (Table 2) data were recorded from 73 SARS-CoV-2 infected pts. Sixty (80%) pts had lymphoid and 15 (20%) had myeloid neoplasms, 2 with concurrent lymphoid and myeloid neoplasms. Thirty-seven (51%) pts were undergoing active treatment for their malignancy. Twenty-one pts (29%) were managed in the ambulatory setting while 52 (71%) required hospital admission. Twenty-five (34%) pts required advanced respiratory support including 14 (19%) who required mechanical ventilation. Four pts (6%) had thrombotic events and 31 (42%) received SARS-CoV-2-directed therapies. Sixteen pts (22%) died during the study period. Pts on active cancer treatment had higher rates of hospital admission (81% v 60%; p=0.05) and AKI (51% v 29%; p=0.04) but similar rates of death compared with pts not on active treatment (24% v 20%; p=0.66) (Table 3). Comparing pts who received SARS-CoV-2 -directed therapy versus no therapy: pts on therapy had longer median lengths of stay (11 v 7 days; p=0.04) and higher rates of hospital admission (94% v 55%; p=0.0003) but similar rates of death (23% v 21%; p=0.91); pts in the ICU on SARS-COV-2 -directed therapy had lower rates of death (38% v 88% p=0.02) than pts who did not receive such therapy (Table 4). Twenty-six pts (36%) were tested for viral clearance, defined as two serial negative swabs ≥24 hours apart. Of these, 17 (65%) achieved clearance with a median time of 51 days (range 15-119 days). Thirteen pts (18%) had antibody (Ab) testing. Ten (77%) had detectable Abs: 8 were positive for IgG, 1 for IgG and IgM, and 1 had unspecified positivity. Notably, all 3 pts with undetectable Abs were on active cancer treatment. Conclusion: We demonstrate that pts with hematologic malignancies are exceptionally vulnerable to severe forms of SARS-CoV-2 with high mortality rates. The incidence of thrombotic events was low, an unexpected finding in the setting of a hyperinflammatory syndrome. Prolonged time to viral clearance was observed, a finding which may cause potential delays in the resumption of cancer-directed therapies. Notably, the majority of pts who received antibody testing had detectable antibodies suggesting that pts with hematologic malignancies may be able to mount an immune response to early vaccination. Accordingly, close monitoring, aggressive therapy, and early vaccination, when available, may be warranted for this population. Larger studies are needed to confirm our findings and help guide management of pts with hematologic malignancies during the SARS-CoV-2 pandemic. Disclosures Altman: Bristol-Myers Squibb: Consultancy; Janssen: Consultancy; Immune Pharmaceuticals: Consultancy; Syros: Consultancy; Genentech: Research Funding; Novartis: Consultancy; Amphivena: Research Funding; Amgen: Research Funding; Aprea: Research Funding; ImmunoGen: Research Funding; Celgene: Research Funding; Boehringer Ingelheim: Research Funding; Fujifilm: Research Funding; Kartos: Research Funding; AbbVie: Other: advisory board, Research Funding; Kura Oncology: Other: Scientific Advisory Board - no payment accepted, Research Funding; BioSight: Other: No payment but was reimbursed for travel , Research Funding; Daiichi Sankyo: Other: Advisory Board - no payment but was reimbursed for travel; Agios: Other: advisory board, Research Funding; Glycomimetics: Other: Data safety and monitoring committee; Astellas: Other: Advisory Board, Speaker (no payment), Steering Committee (no payment), Research Funding; Theradex: Other: Advisory Board; ASH: Consultancy; Cancer Expert Now: Consultancy; France Foundation: Consultancy; PeerView: Consultancy; PrIME Oncology: Consultancy. Winter:Delta Fly Pharma: Consultancy; Amgen: Consultancy; Epizyme: Other: DSMB; CVS/Caremark: Consultancy; Ariad/Takeda: Consultancy; Norvartis: Consultancy, Other: DSMB; Merck: Membership on an entity's Board of Directors or advisory committees, Other: advisory board; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: advisory board. Gordon:Zylem Biosciences: Patents & Royalties: Patents, No Royalties. Pro:Verastem Oncology: Research Funding. Ma:TG Therapeutics: Research Funding; Juno: Research Funding; Novartis: Research Funding; Kite: Consultancy, Honoraria; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; BeiGene: Honoraria, Research Funding, Speakers Bureau; Bioverativ: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau. Karmali:BMS/Celgene/Juno: Honoraria, Other, Research Funding, Speakers Bureau; Takeda: Research Funding; Karyopharm: Honoraria; Gilead/Kite: Honoraria, Other, Research Funding, Speakers Bureau; AstraZeneca: Speakers Bureau; BeiGene: Speakers Bureau.

Background: DLBCL is highly heterogeneous in underlying biology and clinical behavior. Several high-risk disease features and poor prognostic factors are associated with a higher propensity for refractory disease or relapse after standard R-CHOP therapy; these subset patients require novel strategies to improve upon outcomes. Single-agent TAK-659, a novel oral SYK inhibitor, has demonstrated efficacy in heavily pre-treated DLBCL (Gordon et al., Clin Cancer Res, 2020). We report results of a phase I single institution, single arm dose escalation study that assessed safety of 1 st line treatment with R-CHOP and adjunctive TAK-659 for treatment naïve high-risk DLBCL. Methods: Patients aged ≥18 years, ECOG 0-2 with untreated stage I-IV DLBCL with high-risk features defined as, ABC/non-GCB subtype, high-intermediate or high-risk NCCN-IPI (score ≥4), MYC gene rearranged by FISH including double hit lymphoma (DHL), double expressing DLBCL (DEL; overexpression of MYC ≥40% AND BCL2 ≥50% by IHC respectively), or previously treated transformed low-grade lymphoma without prior exposure to anthracycline, were eligible. Patients were treated with R-CHOP for 1 cycle on or off study followed by combined treatment with R-CHOP and TAK-659 for an additional 5 cycles on study. TAK-659 was dosed daily with dosing escalated from 60mg (dose level 1), to 80mg (dose level 2) to 100mg (dose level 3) based on a 3+3 design. The primary objective was to determine the safety and establish the maximum tolerated dose of TAK-659 when combined with R-CHOP in the front-line treatment of high-risk DLBCL. Secondary objectives were to assess preliminary efficacy of this combination as determined by overall response rate (ORR) by PET-CT (Lugano 2014 criteria), progression free survival (PFS), overall survival (OS) and establish the pharmacokinetics of TAK-659 according to dose. Results: 12 pts were enrolled from Dec 2019 to Nov 2021. The median age was 64 yrs (range 25-75); 8 (67%) had stage III/IV disease, 4 (33%) with high risk NCCN-IPI ≥ 4. Histology included 7 (58%) with de novo DLBCL (4 GCB, 3 non-GCB subtype DLBCL) including 7 (58%) with DEL, 3 (25%) with transformed FL, 1 (8%) with Richter's and 1 (8%) with DHL. Dose level 3 (100 mg) was established as the MTD. PKs were measured pre- and post-dose D1 and D15 of cycle 2; Cuzick's test signaled an increase in AUC by dose level on D1 (p = 0.01) but not on D15 (Fig 1). ORR was 100% (CR 92%; Fig 2). With a median follow-up of 14.2 months, 1 pt had primary refractory disease (ABC and DEL), 2 pts with CR subsequently progressed (1 non-GC DLBCL, 1 Richter's) and 1 died of cardiogenic shock unrelated to study drug. The 12-month PFS and OS rates were 82% and 90% respectively with estimated 18-month PFS and OS rates of 68% and 90% respectively. The most common treatment related adverse events (TRAEs) attributed to TAK-659 were lymphopenia (n=12, 100%), infection (6=, 50%), AST elevation (n = 12, 100%) and ALT elevation (n = 10, 83%) (Table). Incidence and severity of transaminitis was consistent with prior reports for this agent. Most common grade 3/4 toxicities were hematologic. Median number of cycles of TAK-659 delivered was 5 (range 3-5). TRAEs led to TAK-659 dose modifications in 8 (67%) pts, though none at dose level 1: 2 (17%) required permanent dose reductions (both for lung infections), while 5 (42%) required discontinuation (4 for infection, and 1 for febrile neutropenia). R-CHOP administration was delayed in 2 pts because of TAK-659 related TRAEs. Aside from dose modifications of vincristine for peripheral neuropathy, no additional dose modifications for R-CHOP were needed. Infections encountered included bacterial and opportunistic infections (1 each for PJP, CMV and aspergillosis) and 1 case of COVID. Growth factor prophylaxis and anti-fungal therapy were not mandated; PJP prophylaxis was advised for CD4 counts < 200 at initial diagnosis. Conclusion: TAK-659, a novel SYK inhibitor combined with R-CHOP in pts with newly diagnosed high-risk DLBCL including DLBCL transformed from follicular lymphoma and DEL produces high CR rates; survival at 12 months appears promising. A dose of 60 mg was well tolerated, did not require dose modifications and maintained a similar AUC to the MTD of 100 mg with ongoing treatment. Opportunistic infections were noted with this treatment combination suggesting that patients should receive aggressive anti-microbial prophylaxis with future evaluation of this combination. Figure 1 Figure 1. Disclosures Karmali: BeiGene: Consultancy, Speakers Bureau; Morphosys: Consultancy, Speakers Bureau; Kite, a Gilead Company: Consultancy, Research Funding, Speakers Bureau; Takeda: Research Funding; Karyopharm: Consultancy; EUSA: Consultancy; Janssen/Pharmacyclics: Consultancy; AstraZeneca: Speakers Bureau; BMS/Celgene/Juno: Consultancy, Research Funding; Genentech: Consultancy; Epizyme: Consultancy; Roche: Consultancy. Ma: Beigene: Research Funding, Speakers Bureau; Juno: Research Funding; AstraZeneca: Honoraria, Research Funding, Speakers Bureau; Loxo: Research Funding; Janssen: Research Funding, Speakers Bureau; Abbvie: Honoraria, Research Funding; TG Therapeutics: Research Funding; Pharmacyclics: Research Funding, Speakers Bureau. Winter: BMS: Other: Husband: Data and Safety Monitoring Board; Agios: Other: Husband: Consultancy; Actinium Pharma: Consultancy; Janssen: Other: Husband: Consultancy; Epizyme: Other: Husband: Data and Safety Monitoring Board; Gilead: Other: Husband: Consultancy; Ariad/Takeda: Other: Husband: Data and Safety Monitoring Board; Karyopharm (Curio Science): Honoraria; Merck: Consultancy, Honoraria, Research Funding; Novartis: Other: Husband: Consultancy, Data and Safety Monitoring Board. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. OffLabel Disclosure: TAK-659 will be discussed for the treatment of DLBCL (not FDA approved for this indication)

Introduction The treatment of aggressive B-cell NHL has evolved rapidly over the last 5 years, owing to the FDA approval of 3 CD19 CAR T-cell constructs (CARTs) along with other novel targeted therapies. Real world practice data suggest that CARTs have been successfully administered in populations typically excluded from clinical trials. However, data on how to best utilize novel targeted agents as a pathway to CARTs and feasibility of CARTs in rare histologies remains limited. This retrospective multicenter study describes patient (pt) selection and practice patterns in pts treated with CD19 CARTs and provides insight on feasibility of CARTs in special populations. Methods Adult pts with R/R aggressive B-cell NHL treated with CD19 CARTs between 2015- 2020 across 12 US academic centers were identified. Data on demographic and clinical characteristics, disease and toxicity outcomes were collected. Univariate analyses (UVA) were performed to determine impact of demographic/clinical variables on survival. Survival curves were calculated using Kaplan-Meier method. Subgroup analysis was performed for pts with secondary central nervous system lymphoma (sCNSL). Results Clinical and demographic features were recorded from 400 pts (Table 1). Median age was 59 years (range 18-84). Of 271 pts with immunohistochemistry data, 79 (29%) had double-expressor lymphoma. Of 178 pts with FISH data captured, 62 (35%) had double/triple-hit lymphoma. Most common histological subtypes included 271 (68%) pts with de novo DLBCL, 81 (20%) with transformed FL, 13 (3%) with Richter's syndrome, and 8 (2%) with PMBCL. Rare histologies included 7 (2%) with transformed MZL, 5 (1%) with PTLD and 2 (0.5%) with grey zone lymphoma. 24 (6%) pts had sCNSL at time of CART apheresis. Two (0.5%) pts were HIV-positive. Median number of lines of therapy prior to CART was 2 (range 1-8); 182 (46%) pts received ≥ 3 lines. 114 (28%) pts previously had an autologous stem cell transplant. Targeted therapies used as salvage regimens at any point prior to CART are listed in Table 2: commonly used salvage targeted therapies included lenalidomide based therapy (imids, n=37, 9%), BTK inhibitors (BTKis, n=30, 8%), checkpoint inhibitors (CBIs, n=17, 4%) and polatuzumab-containing regimens (n=10, 3%). 2 (1%) pts received loncastuximab, and no pts received tafasitamab. Six (1.5%) pts proceeded to CART despite complete response to most recent pre-CART therapy. 191 (48%) pts received bridging between apheresis and CART infusion, choice of bridging noted in Table 2: the majority received chemotherapy (n=103, 54%); 28 (15%) received radiation (XRT); 25 (13%), 24 (13%) and 18 (9%) pts received imids, polatuzumab-containing regimens, or BTKis, respectively. With median follow-up of 22.4 months (mo) for the overall group, median (m) PFS was 11 mo (n=363); mOS, was 27 mo (n=397; Fig 1). Pts with sCNSL had a mPFS and mOS of 2 and 4 mo, respectively (Fig 1). On UVA, factors predicting poorer PFS and OS in the overall group included ≥3 pre-CART lines (p For outcomes according to bridging regimens: mPFS after CART for most commonly used systemic bridging therapies was 86 days (d) for platinum-based chemotherapy, 77 d for imids, 90 d for BTKis, 98 d for polatuzumab-bendamustine/rituximab, and 274 d for XRT. Median PFS for XRT bridging (274 d) was statistically better when compared to mPFS for listed systemic therapies combined (p Conclusion Survival outcomes with CARTs in our data set are consistent with those reported in clinical trial settings. CARTs are utilized in real world practice in rare subsets of aggressive R/R B-cell NHL not routinely included in clinical trials. Despite early data suggesting pts with sCNSL benefit from CART, our data suggest outcomes with CART are dismal in this group. Targeted therapies including imids, polatuzumab, BTKis and CBIs are feasible choices for salvage and/or bridging as a pathway to CARTs. Bridging with XRT resulted in improved mPFS post CART as compared to bridging with systemic therapies and suggests differences in pt selection for each with systemic therapies likely favored in those with more widespread disease burden. Minimal use of CD19-targeted agents pre-CART is attributed to later approval of these agents and concern for potential loss of CD19 antigen leading to CART resistance. Figure 1 Figure 1. Disclosures Cohen: Janssen, Adicet, Astra Zeneca, Genentech, Aptitude Health, Cellectar, Kite/Gilead, Loxo, BeiGene, Adaptive: Consultancy; Genentech, BMS/Celgene, LAM, BioINvent, LOXO, Astra Zeneca, Novartis, M2Gen, Takeda: Research Funding. Shouse: Kite Pharma: Speakers Bureau; Beigene: Honoraria. Hess: ADC Therapeutics: Consultancy; BMS: Speakers Bureau. Stephens: Beigene: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; Epizyme: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Adaptive: Membership on an entity's Board of Directors or advisory committees; Arqule: Research Funding; Mingsight: Research Funding; JUNO: Research Funding; Celgene: Consultancy; CSL Behring: Consultancy; AstraZeneca: Consultancy; Abbvie: Consultancy; Innate Pharma: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding. Ma: Loxo: Research Funding; AstraZeneca: Honoraria, Research Funding, Speakers Bureau; Juno: Research Funding; Beigene: Research Funding, Speakers Bureau; Abbvie: Honoraria, Research Funding; Janssen: Research Funding, Speakers Bureau; TG Therapeutics: Research Funding; Pharmacyclics: Research Funding, Speakers Bureau. Winter: BMS: Other: Husband: Data and Safety Monitoring Board; Actinium Pharma: Consultancy; Janssen: Other: Husband: Consultancy; Gilead: Other: Husband: Consultancy; Agios: Other: Husband: Consultancy; Epizyme: Other: Husband: Data and Safety Monitoring Board; Merck: Consultancy, Honoraria, Research Funding; Novartis: Other: Husband: Consultancy, Data and Safety Monitoring Board; Ariad/Takeda: Other: Husband: Data and Safety Monitoring Board; Karyopharm (Curio Science): Honoraria. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. Danilov: Astra Zeneca: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Honoraria, Research Funding; Takeda Oncology: Research Funding; TG Therapeutics: Consultancy, Research Funding; Abbvie: Consultancy, Honoraria; Beigene: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; Gilead Sciences: Research Funding; Bristol-Meyers-Squibb: Honoraria, Research Funding; Rigel Pharm: Honoraria; Bayer Oncology: Consultancy, Honoraria, Research Funding; SecuraBio: Research Funding. Shah: Umoja: Consultancy; Legend: Consultancy; Kite: Consultancy; Miltenyi Biotec: Consultancy, Honoraria, Research Funding; Lily: Consultancy, Honoraria, Research Funding; Epizyme: Consultancy; Incyte: Consultancy. Barta: Seagen: Honoraria; Daiichi Sankyo: Honoraria; Acrotech: Honoraria; Kyowa Kirin: Honoraria. Epperla: Genzyme: Honoraria; Karyopharm: Other: Ad Board; Beigene: Speakers Bureau; Verastem: Speakers Bureau. Torka: TG Therapeutics: Membership on an entity's Board of Directors or advisory committees. Karmali: Epizyme: Consultancy; BeiGene: Consultancy, Speakers Bureau; EUSA: Consultancy; Roche: Consultancy; AstraZeneca: Speakers Bureau; Morphosys: Consultancy, Speakers Bureau; Karyopharm: Consultancy; Takeda: Research Funding; BMS/Celgene/Juno: Consultancy, Research Funding; Janssen/Pharmacyclics: Consultancy; Genentech: Consultancy; Kite, a Gilead Company: Consultancy, Research Funding, Speakers Bureau.

Introduction: Treatment of relapsed and refractory aggressive B cell lymphomas is challenging, especially after autologous stem cell transplant or chimeric antigen receptor T cell therapy. CpG oligodeoxynucleotides (CpGs) mimic bacterial DNA and bind to toll-like receptor 9 (TLR9). TLR9 is expressed in the endosomes of innate immune cells and B lymphocytes as well as B cell lymphomas. CpG binding to TLR9 in these cells leads to a pro-inflammatory response and induces apoptosis of lymphoma cells by altering NF-kB activation. However, clinical utility of CpGs is limited due to difficulties delivering the DNA directly to the innate immune cells and lymphoma cells, and these DNA strands are easily degraded in biological fluids. Therefore, we designed a nano-carrier to deliver two classes of CpGs to improve clinical efficacy of CpGs in treating lymphoma. Class B CpGs (B-CpGs) mainly stimulate B cells while class C CpGs (C-CpGs) act on both B cells and plasmacytoid dendritic cells. Though C-CpGs are the focus of current clinical trials, B-CpGs may have a special a role in the treatment of lymphoma due to their more potent, direct cytotoxic effect on the malignant lymphoma cells. Here, we evaluated the anti-lymphoma effect of the combination of B-CpG nanoparticles (BNP) and C-CpG nanoparticles (CNP) by optimizing lymphoma cell death and immune stimulation. Methods: BNP and CNP were synthesized by surface-functionalizing gold nanoparticles with modified B-CpGs and C-CpGs, followed by purification via centrifugation. We used a dual flank tumor murine lymphoma model to evaluate the local and systemic anti-lymphoma efficacy of the CpG NPs and screen for the most effective formulation. A20 lymphoma tumors were implanted on both flanks of Balb/c mice. When the tumors were 5-7mm in diameter, various treatments were injected intratumorally on days 1, 4, and 8 on the side with the larger tumor. Treatment groups include PBS, B-CpG, C-CpG, B+C-CpG, BNP, CNP, BNP+CNP. Free CpGs were injected at 50ug/ml in 50ul (2.5ug CpG per injection) and nanoparticles at 100nM (equivalent to 50ug/ml CpGs) in 50ul. Tumor growth were measured every other day. Event is defined as tumor volume > 3cm 3. Second, we used an advanced disease lymphoma model to evaluate intravenous delivery of combination NPs. We implanted A20 lymphoma cells on a flank tumor (on day -14), then we injected A20 cells intravenously to mimic advanced disease (on day -7). We treated the mice with intravenous (tail vein) injections of PBS, B+C-CpG, or BNP+CNP on days 1, 4, and 8. Results: We found that the combination of BNP and CNPs had the most significant reduction in total tumor volume (TTV) (treated + untreated tumor size) (393mm 3 on day 22). The PBS group demonstrated rapid tumor growth (TTV 3516mm 3). The experimental treatment groups, B-CpG (TTV 949mm 3),, C-CpG (TTV 2230mm 3), B+C-CpGs (TTV 1680mm 3), BNP (TTV 1224mm 3), and CNP (1894mm 3) had similar TTV growth curves. Separating the treated tumor and untreated tumor growth curves, we found that B-CpG and BNP along with combination of BNP+CNP had the best tumor suppression on the treated side. This is not surprising as B-CpG sequences are more directly cytotoxic to lymphoma cells versus C-CpGs. Interestingly, combination nanoparticle treatment (BNP+CNP) was the only group that had significantly reduced tumor growth of the untreated tumor compared with all other conditions (p Conclusions: Overall, the combination of class B and class C CpG nanoparticles can generate a strong in situ anti-lymphoma vaccination response, presumably through the combination of by combining the superior cytotoxicity of BNPs with the enhanced immune stimulation effect of the CNPs. Further evaluation of the combined mechanism of action of this dual CpG nanoparticle approach and toxicity studies are in progress. Disclosures Thaxton: Zylem biosciences: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding.

Dosing with duvelisib 25 mg BID has been shown to be efficacious in iNHL, most notably the pivotal phase 2 DYNAMO study (NCT01882803) in follicular lymphoma (FL). The TEMPO study (NCT04038359) was designed to examine the effects of prespecified 2-week dose holidays on tumor responses and safety/tolerability in patients with iNHL (FL, MZL), based on data from a phase 3 trial (DUO) in CLL/SLL which demonstrated no negative impacts of (unscheduled) dose interruptions on response. In TEMPO, patients were randomized to receive duvelisib 25 mg BID for one 10-week cycle followed by 25 mg BID on Weeks 3 and 4 of each subsequent 4-week cycles (Arm 1) or duvelisib 25 mg BID on Weeks 1, 2, 5, 6, 9 and 10 of one 10-week cycle, then on Weeks 3 and 4 of each subsequent 4-week cycles (Arm 2). Patients continued treatment until disease progression, unacceptable toxicity, or withdrawal. As of May 5, 2021 data cutoff, a total of 65 treated pts had at least 4 months of follow up on or after study drug treatment. Across both arms, the median age was 63 years (range 34-85), and 47 (72.3%) of the patients remained on study treatment at the time of this analysis (table 1). 18 of 65 pts (27.7%) discontinued therapy; 13 of 65 pts (19.7%) discontinued due to PD: 7 out of 33 (21.2%) in arm 1 and 6 out of 32 (18.8%) in arm 2. Of the remaining 5 pts (out of 65 patients) that discontinued, all were in arm 1: 4 out of 33 pts (12.1%) due to adverse events and 1 out of 33 (3%) due to study drug interruption > 42 days. Across both arms, the ORR was 60% (39 of 65 pts), and the CR rate was 12.3% (8 of 65 pts). See table 2 for responses by arm. Grade > 3 AEs were higher in Arm 1 vs Arm 2, with the exception of neutropenia: elevated ALT/AST was 30.3%/27.3% vs 3.1%/3.1%; neutropenia 9.1% vs 18.8%; GI disorders 9.1% vs 0; infections 9.1% vs 3.1%; rash 6.1% vs 3.1%; and drug reaction with eosinophilia 3% vs 0 -- respectively. Discontinuation of study drug due to AEs only occurred in arm 1, in 5 out of 33 patients (15.2%), and were due to ALT/AST elevations (2 of 33 pts, 6.1%); skin and subcutaneous tissue disorders (2 of 33 pts, 6.1%); and pneumonia (1 of 33 pts, 3.0%). In summary, based on this interim analysis, continuous dosing followed by intermittent dosing (arm 1) and intermittent dosing (arm 2) are both efficacious in patients with iNHL. The ORR and CR are similar to those seen in DYNAMO. The study confirms the overall safety profile of duvelisib, demonstrating that intermittent dosing may well decrease the incidence of side effects without compromising efficacy. Figure 1 Figure 1. Disclosures Vorobyev: Janssen, Roche, Sanofi, Takeda, Biocad, Abbvie: Other: Advisory Boards, Speakers Bureau; Astellas, Novartis, AstraZeneca: Speakers Bureau. Tarella: ADC-THERAPEUTICS: Other: ADVISORY BOARD; Abbvie: Other: ADVISORY BOARD. Litwak: Secura Bio: Current Employment. Cohan: Secura Bio: Current Employment. Flinn: Celgene: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Great Point Partners: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; BeiGene: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Agios: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; IGM Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; AbbVie: Consultancy, Other: All Consultancy and Research Funding payments made to Sarah Cannon Research Institute, Research Funding; Verastem: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Curis: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Incyte: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Infinity Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Forty Seven: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; ArQule: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Novartis: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Merck: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Constellation Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Unum Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Teva: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Trillium Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; AstraZeneca: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; MorphoSys: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Forma Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Takeda: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Acerta Pharma: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; TG Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Loxo: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Kite, a Gilead Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Nurix Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Pharmacyclics LLC, an AbbVie Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Roche: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Iksuda Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Janssen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Juno Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Seagen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Rhizen Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Genentech: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Gilead Sciences: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Calithera Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Karyopharm Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Pfizer: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Portola Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Triphase Research & Development Corp.: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Century Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Hutchison MediPharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Vincerx Pharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Sarah Cannon Research Institute: Current Employment; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Seagen: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Unum Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute, Research Funding; Johnson & Johnson: Current holder of individual stocks in a privately-held company; Seattle Genetics: Research Funding. Zinzani: CELLTRION: Other: Advisory board, Speakers Bureau; GILEAD: Other: Advisory board, Speakers Bureau; JANSSEN-CILAG: Other: Advisory board, Speakers Bureau; BMS: Other: Advisory board, Speakers Bureau; TG Therapeutics: Other: Advisory board, Speakers Bureau; TAKEDA: Other: Advisory board, Speakers Bureau; SERVIER: Other: Advisory board, Speakers Bureau; MSD: Consultancy, Other: Advisory board, Speakers Bureau; Beigene: Other, Speakers Bureau; Incyte: Other, Speakers Bureau; KYOWA KIRIN: Other, Speakers Bureau; EUSAPHARMA: Consultancy, Other, Speakers Bureau; ROCHE: Other, Speakers Bureau; SANDOZ: Other: Advisory board; NOVARTIS: Consultancy, Other, Speakers Bureau; ADC Therap.: Other; VERASTEM: Consultancy, Other: Advisory board, Speakers Bureau. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. OffLabel Disclosure: duvelisib is a PI3K inhibitor indicated for the treatment of relapsed/refractory CLL/SLL and FL. The approved dose of duvelisib is 25mg BID. A cycle consists of every 28 days.

Introduction: Radioimmunotherapy is a targeted approach to cancer care. It has been shown to improve progression-free survival and quality of life in people with specific types of non-Hodgkin's lymphoma, including CD20- and CD37-positive B-cell lymphoma (Barr et al., 2018 NCT00770224; Green & Press, 2017; Kolstad et al., 2018 NCT01796171; Witzig et al., 2002). It has also been shown to increase the proportion of people who achieve complete response to therapy (Green & Press, 2017). Although CD20-targeted therapy has been approved in the US and Europe for nearly two decades, its use remains limited. At its peak in the UK in 2007, only 57 people with lymphoma were treated with the therapy (Rojas et al., 2019). However, research is ongoing; a PubMed search for 'radioimmunotherapy' and 'lymphoma' produces 1,097 articles in the past 20 years, including over 300 articles in the past ten years. With novel applications (CD37- and CD22-targeted) currently under investigation, it is increasingly important to understand potential system and policy barriers to uptake, such that existing roadblocks are overcome. Tackling these challenges is essential to ensuring that radioimmunotherapy is appropriately integrated into relevant clinical guidelines and care pathways. Aim: To better understand the policy and system barriers to integration of existing and novel radioimmunotherapy into lymphoma care in the US and the UK. Methodology: We conducted a structured literature review, taking a systems approach, to explore each of the five domains of the health system as outlined in the Radioligand Therapy Readiness Assessment Framework (Figure 1. Five core domains of the health system, with subdomains; The Health Policy Partnership, 2021). This approach allowed us to gain a holistic understanding of what integration of radioimmunotherapy involves and identify potential barriers, from clinical development through to patient care. We also conducted semi-structured interviews with lymphoma experts in the US (N=5) and UK (N=6), including clinicians and nurses ('clinical experts', N=8) and patient advocates ('advocates', N=3). Our work was guided by national expert advisory groups in each country. Results: While the US and UK health systems are organized and funded very differently, the literature and expert interviews revealed many common strategic challenges to the integration of radioimmunotherapy. These were: 1) low awareness and understanding of radioimmunotherapy among newly licensed healthcare professionals (an issue raised by n=8 clinical experts); 2) limited awareness by patient advocates, patients and policymakers (n=3 advocates); 3) caution around uptake of new radioimmunotherapy agents based on limited access to and use of older treatments (n=7 clinical experts); 4) nonexistent referral pathways and unclear models of working which discourage shared care and hinder multidisciplinary coordination (n=4 clinical experts); 5) lack of recent clinical data and research to support evidence-based use (n=5 clinical experts); 6) reimbursement concerns (n=5 clinical experts). Policy implications: Taking a systems approach to explore potential barriers to integration of radioimmunotherapy has allowed us to explore potential adaptations needed to achieve multisectoral and multidisciplinary working. Our findings reveal that professional societies, policymakers and patient advocacy groups will need to work together to overcome these barriers by: 1) reaching consensus on timing and eligibility criteria for use of radioimmunotherapy; 2) creating accurate and consistent patient-friendly information; 3) efficiently updating clinical training and treatment guidelines to include approved radioimmunotherapy; 4) developing evidence-based and personalized referral and treatment pathways which ensure consistency of care; and 5) investing in data collection and analysis to continually inform practice. Figure 1 Figure 1. Disclosures Morgan: Nordic Nanovector: Consultancy; Advanced Accelerator Applications: Consultancy. Merkel: Advanced Accelerator Applications: Consultancy; Amgen: Consultancy; AstraZeneca: Consultancy; Bayer: Consultancy; Bristol-Myers Squibb: Consultancy; Curium: Consultancy; Johnson & Johnson: Consultancy; MSD: Consultancy; Nordic Nanovector: Consultancy; Novartis: Consultancy. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. Buscombe: Advanced Accelerator Applications Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Wait: Bayer: Consultancy; Curium: Consultancy; Johnson & Johnson: Consultancy; MSD: Consultancy; Advanced Accelerator Applications: Consultancy; Nordic Nanovector: Consultancy; Shionogi: Consultancy; Bristol-Myers Squibb: Consultancy; Amgen: Consultancy; AstraZeneca: Consultancy. Dreyling: Genmab: Consultancy; Celgene: Consultancy, Research Funding, Speakers Bureau; Amgen: Speakers Bureau; Astra Zeneca: Consultancy, Speakers Bureau; Bayer HealthCare Pharmaceuticals: Consultancy, Research Funding, Speakers Bureau; BeiGene: Consultancy; Gilead/Kite: Consultancy, Research Funding, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Janssen: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Roche: Consultancy, Research Funding, Speakers Bureau; Abbvie: Research Funding. Mittra: Advanced Accelerator Applications Novartis: Consultancy, Honoraria, Research Funding; Curium: Consultancy, Honoraria; Nordic Nanovector: Research Funding. Gopal: Janssen: Consultancy, Honoraria, Research Funding; Cellectar: Consultancy, Honoraria; Bristol Meyers Squibb: Research Funding; SeaGen: Consultancy, Honoraria, Research Funding; I-Mab bio: Consultancy, Honoraria, Research Funding; Incyte: Honoraria; MorphoSys: Honoraria; Servier: Consultancy, Honoraria; Genetech: Consultancy, Honoraria, Research Funding; IGM Biosciences: Research Funding; Astra-Zeneca: Research Funding; Karyopharm: Consultancy, Honoraria; Takeda: Research Funding; Teva: Research Funding; Agios: Research Funding; Kite: Consultancy, Honoraria; ADC Therapeutics: Consultancy, Honoraria; Acrotech: Consultancy, Honoraria; Merck: Consultancy, Honoraria, Research Funding; Epizyme: Consultancy, Honoraria; Nurix Inc: Consultancy, Honoraria; Beigene: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Research Funding.

Background: The standard of care (SOC) treatment (Tx) in the curative setting for patients (pts) with relapsed/refractory (R/R) large B-cell lymphoma (LBCL) after 1st-line (1L) chemoimmunotherapy (CIT) is high-dose therapy with autologous stem cell rescue (HDT-ASCT) if responsive to 2L CIT; however, as many pts do not respond to or cannot tolerate 2L CIT, or are not intended for HDT-ASCT, outcomes remain poor. Axi-cel is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved for R/R LBCL after ≥2 prior systemic therapies. Since CAR T-cell therapy may benefit pts in earlier lines of therapy, we conducted ZUMA-7 (NCT03391466), a global, randomized, Phase 3 trial of axi-cel vs SOC in pts with 2L R/R LBCL, and report here the results of the primary analysis (PA). Methods: Eligible pts were ≥18 y with LBCL, ECOG PS 0-1, R/R disease ≤12 mo of adequate 1L CIT (including anti-CD20 monoclonal antibody and an anthracycline), and intended to proceed to HDT-ASCT. Pts were randomized 1:1 to axi-cel or SOC, stratified by 1L Tx response and 2L age-adjusted IPI (sAAIPI). In the axi-cel arm, pts received a single infusion of 2×10 6 CAR T cells/kg after conditioning (3 d; cyclophosphamide 500 mg/m 2/day and fludarabine 30 mg/m 2/day). Optional bridging Tx was limited to corticosteroids (CIT was not allowed). In the SOC arm, pts received 2-3 cycles of an investigator-selected, protocol defined, platinum-based CIT regimen; pts with partial response or complete response (CR) proceeded to HDT-ASCT. Disease assessments by PET-CT per Lugano Classification occurred at timepoints specified from randomization. Although there was no planned trial crossover between arms, pts not responding to SOC could receive CAR T-cell therapy off protocol. Axi-cel was hypothesized to result in a 50% improvement in event-free survival (EFS: time to earliest date of disease progression, death from any cause, or new lymphoma Tx) vs SOC. The PA was event-driven, and the primary endpoint was EFS by blinded central review. Key secondary endpoints, tested hierarchically, were objective response rate (ORR) and overall survival (OS; interim analysis); safety was also a secondary endpoint. Level of CAR T cells was an exploratory endpoint. Results: As of 3/18/21, 359 pts were enrolled globally. The median age was 59 y (range, 21-81; 30% ≥65 y). Overall, 74% of pts had primary refractory disease and 46% had high sAAIPI (2-3). Of 180 pts randomized to axi-cel, 170 (94%) were infused; of 179 pts randomized to SOC, 64 (36%) reached HDT-ASCT after 2L CIT. The primary endpoint of EFS was met (HR: 0.398; P Conclusions: ZUMA-7, the first randomized, global, multicenter Phase 3 study of axi-cel vs 2L SOC in R/R LBCL, demonstrated a statistically significant and clinically meaningful improvement in EFS. Axi-cel showed superiority over SOC with >4-fold greater median EFS, 2.5-fold greater EFS at 2 y, double the CR rate, and more than double the percentage of pts receiving definitive Tx. Safety of axi-cel was manageable and at least consistent with 3L axi-cel therapy. Axi-cel may replace CIT/HDT-ASCT as the SOC for 2L R/R LBCL. These data are reported on behalf of all ZUMA-7 investigators and contributing Kite members. Disclosures Locke: Novartis: Consultancy, Other, Research Funding; Janssen: Consultancy, Other: Scientific Advisory Role; Kite, a Gilead Company: Consultancy, Other: Scientific Advisory Role, Research Funding; Iovance Biotherapeutics: Consultancy, Other: Scientific Advisory Role; GammaDelta Therapeutics: Consultancy, Other: Scientific Advisory Role; Umoja: Consultancy, Other; Wugen: Consultancy, Other; Takeda: Consultancy, Other; Legend Biotech: Consultancy, Other; EcoR1: Consultancy; Emerging Therapy Solutions: Consultancy; Gerson Lehrman Group: Consultancy; Cowen: Consultancy; Calibr: Consultancy, Other: Scientific Advisory Role; Moffitt Cancer Center: Patents & Royalties: field of cellular immunotherapy; Cellular Biomedicine Group: Consultancy, Other: Scientific Advisory Role; BMS/Celgene: Consultancy, Other: Scientific Advisory Role; Bluebird Bio: Consultancy, Other: Scientific Advisory Role; Amgen: Consultancy, Other: Scientific Advisory Role; Allogene Therapeutics: Consultancy, Other: Scientific Advisory Role, Research Funding. Miklos: Pharmacyclics, Amgen, Kite, a Gilead Company, Novartis, Roche, Genentech, Becton Dickinson, Isoplexis, Miltenyi, Juno-Celgene-Bristol Myers Squibb, Allogene, Precision Biosciences, Adicet, Adaptive Biotechnologies: Research Funding; Adaptive Biotechnologies, Novartis, Juno/Celgene-BMS, Kite, a Gilead Company, Pharmacyclics-AbbVie, Janssen, Pharmacyclics, AlloGene, Precision Bioscience, Miltenyi Biotech, Adicet, Takeda: Membership on an entity's Board of Directors or advisory committees; Kite, a Gilead Company, Amgen, Atara, Wugen, Celgene, Novartis, Juno-Celgene-Bristol Myers Squibb, Allogene, Precision Bioscience, Adicet, Pharmacyclics, Janssen, Takeda, Adaptive Biotechnologies and Miltenyi Biotechnologies: Consultancy; Pharmacyclics: Patents & Royalties. Jacobson: Kite, a Gilead Company: Consultancy, Honoraria, Other: Travel support; Lonza: Consultancy, Honoraria, Other: Travel support; Precision Biosciences: Consultancy, Honoraria, Other: Travel support; Novartis Pharmaceuticals Corporation: Consultancy, Honoraria, Other: Travel support; Nkarta: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Other: Travel support, Research Funding; Celgene: Consultancy, Honoraria, Other: Travel support; Humanigen: Consultancy, Honoraria, Other: Travel support; Axis: Speakers Bureau; Clinical Care Options: Speakers Bureau. Perales: Cidara: Honoraria; Omeros: Honoraria; Merck: Honoraria; Servier: Honoraria; Medigene: Honoraria; Takeda: Honoraria; Miltenyi Biotec: Honoraria, Other; Sellas Life Sciences: Honoraria; Kite/Gilead: Honoraria, Other; Novartis: Honoraria, Other; Incyte: Honoraria, Other; Equilium: Honoraria; Karyopharm: Honoraria; NexImmune: Honoraria; Celgene: Honoraria; Nektar Therapeutics: Honoraria, Other; MorphoSys: Honoraria; Bristol-Myers Squibb: Honoraria. Kersten: Novartis: Consultancy, Honoraria, Other: Travel support; Kite, a Gilead Company: Consultancy, Honoraria, Other: Travel support, Research Funding; Roche: Consultancy, Honoraria, Other: Travel support, Research Funding; BMS/Celgene: Consultancy, Honoraria; Takeda: Research Funding; Celgene: Research Funding; Miltenyi Biotec: Consultancy, Honoraria, Other: Travel support. Oluwole: Janssen: Consultancy; Kite, a Gilead Company: Consultancy, Research Funding; Pfizer: Consultancy; Curio Science: Consultancy. Ghobadi: Amgen: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Honoraria, Research Funding; Atara Biotherapeutics: Consultancy; Wugen: Consultancy; Celgene: Consultancy. McGuirk: Juno Therapeutics: Consultancy, Honoraria, Research Funding; Kite/ Gilead: Consultancy, Honoraria, Other: travel accommodations, expense, Kite a Gilead company, Research Funding, Speakers Bureau; Novartis: Research Funding; Gamida Cell: Research Funding; Pluristem Therapeutics: Research Funding; Bellicum Pharmaceuticals: Research Funding; Allovir: Consultancy, Honoraria, Research Funding; Magenta Therapeutics: Consultancy, Honoraria, Research Funding; EcoR1 Capital: Consultancy; Novartis: Research Funding; Fresenius Biotech: Research Funding; Astelllas Pharma: Research Funding. Pagel: Incyte/MorphoSys: Consultancy; Gilead: Consultancy; AstraZeneca: Consultancy; Actinium Pharmaceuticals: Consultancy; Pharmacyclics/AbbVie: Consultancy; BeiGene: Consultancy; Epizyme: Consultancy; MEI Pharma: Consultancy; Kite, a Gilead Company: Consultancy. Muñoz: Targeted Oncology, OncView, Kyowa, Physicians' Education Resource, and Seagen: Honoraria; Pharmacyclics, Abbvie, Bayer, Kite, a Gilead Company, Pfizer, Janssen, Juno/Celgene, Bristol Myers Squibb, Kyowa, Alexion, Beigene, Fosun Kite, Innovent, Seagen, Debiopharm, Karyopharm, Genmab, ADC Therapeutics, Epizyme, Beigene, and Servier: Consultancy; Kite, a Gilead Company, Kyowa, Bayer, Pharmacyclics, Janssen, Seagen, Acrotech, Aurobindo, Beigene, Verastem, AstraZeneca, Celgene/Bristol Myers Squibb, Genentech, and Roche: Speakers Bureau; Bayer, Kite, a Gilead Company, Celgene, Merck, Portola, Incyte, Genentech, Pharmacyclics, Seagen, and Janssen, Millennium: Research Funding; OncView: Honoraria; Kyowa Kirin: Honoraria; Physicians' Education Resource: Honoraria. Farooq: Kite, a Gilead Company: Honoraria. Van Meerten: Kite, a Gilead Company: Honoraria; Janssen: Consultancy. Reagan: Genentech: Research Funding; Kite, a Gilead Company: Consultancy; Curis: Consultancy; Seagen: Research Funding. Sureda: Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GSK: Consultancy, Honoraria, Speakers Bureau; Roche: Other: Support for attending meetings and/or travel; Bluebird: Membership on an entity's Board of Directors or advisory committees; Mundipharma: Consultancy; BMS/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Research Funding, Speakers Bureau. Flinn: Loxo: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; AbbVie: Consultancy, Other: All Consultancy and Research Funding payments made to Sarah Cannon Research Institute, Research Funding; Gilead Sciences: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Forma Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Pfizer: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Takeda: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Kite, a Gilead Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Calithera Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Juno Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; ArQule: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Karyopharm Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Nurix Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Great Point Partners: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; BeiGene: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Seagen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; MorphoSys: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Trillium Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Constellation Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Unum Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Janssen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Genentech: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Curis: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Celgene: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Novartis: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; AstraZeneca: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Roche: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; IGM Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Iksuda Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Verastem: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Portola Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Infinity Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Rhizen Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Forty Seven: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Incyte: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Agios: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Teva: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; TG Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Merck: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Acerta Pharma: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Triphase Research & Development Corp.: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Century Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Hutchison MediPharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Vincerx Pharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Sarah Cannon Research Institute: Current Employment; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Seagen: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Unum Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute, Research Funding; Johnson & Johnson: Current holder of individual stocks in a privately-held company; Seattle Genetics: Research Funding. Vandenberghe: Bristol Myers Squibb/Celgene: Consultancy; Pfizer: Research Funding; Gilead Sciences: Consultancy, Other: Travel support; Miltenyi Biotec: Consultancy; Novartis: Consultancy; Janssen: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy. Song: GlaxoSmithKline: Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Janssen: Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb: Honoraria; Kite, a Gilead Company: Honoraria; Sanofi: Honoraria. Dickinson: Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Takeda: Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria; Celgene: Research Funding; Amgen: Honoraria; Roche: Consultancy, Honoraria, Other: travel, accommodation, expenses, Research Funding, Speakers Bureau; Gilead Sciences: Consultancy, Honoraria, Speakers Bureau; MSD: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria. Minnema: Janssen: Consultancy; Alnylam: Consultancy; Kite/Gilead: Consultancy; Cilag: Consultancy; Celgene: Other: Travel expenses; BMS: Consultancy. Riedell: Kite/Gilead: Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BeiGene: Consultancy; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; Calibr: Research Funding; Tessa Therapeutics: Research Funding; Xencor: Research Funding; MorphoSys: Research Funding. Leslie: Karyopharm Therapeutics: Honoraria, Speakers Bureau; BeiGene: Consultancy, Honoraria, Speakers Bureau; Celgene/BMS: Consultancy, Honoraria, Speakers Bureau; Merck: Consultancy; Abbvie: Consultancy, Honoraria; Kite, a Gilead Company: Consultancy, Honoraria, Speakers Bureau; TG Therapeutics: Consultancy, Honoraria, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Pharmacyclics: Consultancy, Honoraria, Speakers Bureau; ADC Therapeutics: Consultancy; Epizyme: Consultancy, Honoraria, Speakers Bureau; PCYC/Janssen: Consultancy, Honoraria, Speakers Bureau; Seagen: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Speakers Bureau. Chaganti: Kite, a Gilead Company: Consultancy, Honoraria, Other: Travel support, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Other: Travel support, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Celgene-BMS: Consultancy, Honoraria, Other: Travel support; Atara Bio: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Research Funding; Incyte: Honoraria, Speakers Bureau. Yang: Kite, a Gilead Company: Current Employment. Filosto: Tusk Therapeutics: Patents & Royalties: or other intellecular property; Gilead Sciences: Other: stock or other ownership ; Kite, a Gilead Company: Current Employment. Schupp: Gilead Sciences: Current equity holder in publicly-traded company; Kite, a Gilead Company: Current Employment, Honoraria, Other: Travel support. To: NantWorks: Ended employment in the past 24 months; Kite, a Gilead Company: Current Employment, Other: stock or other ownership . Cheng: Kite, a Gilead Company: Current Employment, Other: Travel support; Gilead Sciences: Other: stock or other ownership . Gordon: Bristol Myers Squibb: Honoraria, Research Funding; Zylem Biosciences: Patents & Royalties: Patents, No royalties. Westin: Genentech: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Curis: Research Funding; Iksuda Therapeutics: Consultancy; Umoja: Consultancy; ADC Therapeutics: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; MorphoSys: Consultancy, Research Funding; Morphosys: Research Funding; 47 Inc: Research Funding.

Background: Genomic copy number alterations (CNAs) of chromosome 9p24.1 characterize classic Hodgkin lymphoma (cHL) leading to increased expression of programmed cell death ligands -1 and -2 (PD-L1 and PD-L2). Amplifications and high level copy number gains (CNG) have been associated with advanced stage cHL and inferior treatment outcomes with standard chemotherapy. Few studies have assessed 9p24.1 genomic alterations in the frontline setting in the context of PD-1 blockade monotherapy. We conducted a phase 2 clinical trial of sequential pembrolizumab (PEM) x 3 followed by doxorubicin, vinblastine, and dacarbazine (AVD) chemotherapy (4-6 cycles) in newly diagnosed cHL. Interim response to single agent PEM was assessed by PET-CT and by decline in metabolic tumor volume (MTV). Herein, we report updates after extended follow-up of patients (median 33.1 months), and results of correlative studies analyzing 9p24.1 CNAs and PD-1 pathway expression. Methods: Pre-treatment diagnostic biopsy specimens were double stained for PD-L1 (E1L3N, XP Cell Signaling) and PAX5, single stained for PD-L2 and pSTAT3, and scored by two expert hematopathologists (QC, LBS) for percentage positive cells and intensity of staining. A modified H score was calculated as the product of staining intensity (0-3) and percentage of positive tumor cells (0-100%), ranging from 0 - 300 was calculated for PD-L1, PD-L2, and pSTAT3. Fluorescence in situ hybridization (FISH) to assess chromosome 9p24.1 CNAs was performed by co-hybridizing PD-L1/PD-L2 probes (target) with the centromeric 9 probe (control). In each case, the percentage and magnitude of 9p24.1 CNAs were evaluated. Four FISH categories were defined based on the target:control ratio and total copy numbers (CNs) of the target per Hodgkin Reed-Sternberg (HRS) cell to include: amplification (ratio≥3), copy number gain (CNGs) (1≤ratio The relationships between PD-1 pathway markers, genomic alterations, and response to single agent PEM by MTV were assessed statistically using Fisher's Exact test, Kruskal-Wallis test, or Spearman's rank correlation as appropriate. PD-L1 H Scores were grouped into terciles of approximately equal size for categorical analysis. Response was defined as a complete metabolic response (CMR), ≥ 90% reduction in MTV (near CMR), or partial response with < 90% reduction by MTV (PR). Kaplan-Meier curves were used to analyze progression-free survival (PFS) and overall survival (OS). Results: Thirty patients were enrolled from September 2017 through August 1, 2019; 28 had tissue available for FISH analysis and 29 for immunohistochemistry. Patient responses to single agent PEM were PMR in 11 (36.7%), near-CMR in 8 (26.7%), and CMR in 11 (36.7%). CMR rate following AVD x 2 was 100%. With the extended follow-up (median 33.1 months, range 26.0-43.0), PFS and OS both remained at 100% (Figures 1a, 1b). Among 28 cases with available FISH analysis, all patients demonstrated genomic alterations in 9p24.1. The highest level alteration was amplification in 14 patients (50%) and copy number gain in 14 (50.0%) Six of 22 examined cases were EBER-positive. Forty-one percent (n=7) of patients with a CMR or near CMR had amplifications in 9p24.1, compared to 64% (n=7) with a PMR following PEM monotherapy (p=0.2). The median PD-L1 H score was 215 (range 20-300). Of 29 patients assessed, 28% had PD-L1 H scores in the first tercile (H-score 1-190), 34% in the second tercile (190-240), and 38% in the third tercile (240-300). There was no association between response to single agent PEM and 9p24.1 alteration, PD-L1, PD-L2 or STAT3 H-scores, % residual disomy, or EBER status (see Figure 1c for PD-L1 results). Conclusions: We found that after extended follow-up, sequential pembrolizumab and AVD chemotherapy remains a highly effective strategy with 100% of patients remaining alive without relapse. The high response rates observed at all PD-L1/PD-L2 levels in this clinical study suggest that even low levels of PD ligand expression may be sufficient for response to PD-1 blockade in previously untreated cHL. We gratefully acknowledge support from Merck & Co. Figure 1 Figure 1. Disclosures Allen: Kyowa Kirin: Consultancy; Secure Bio: Consultancy; ADC Therapeutics: Consultancy; MorphoSys: Consultancy; Epizyme: Consultancy. Advani: Astellas/Agensys: Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Bristol Myer Squibb: Membership on an entity's Board of Directors or advisory committees; Cell Medica: Membership on an entity's Board of Directors or advisory committees; Forty Seven: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genetech Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceutical: Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Kura: Research Funding; Kyowa: Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Millenium: Research Funding; Pharmacyclics: Consultancy, Research Funding; Portola Pharmaceuticals: Consultancy; Regeneron: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. Winter: Actinium Pharma: Consultancy; BMS: Other: Husband: Data and Safety Monitoring Board; Novartis: Other: Husband: Consultancy, Data and Safety Monitoring Board; Ariad/Takeda: Other: Husband: Data and Safety Monitoring Board; Epizyme: Other: Husband: Data and Safety Monitoring Board; Agios: Other: Husband: Consultancy; Gilead: Other: Husband: Consultancy; Janssen: Other: Husband: Consultancy; Karyopharm (Curio Science): Honoraria; Merck: Consultancy, Honoraria, Research Funding.

Introduction: Approximately 30-35% of patients with classic Hodgkin Lymphoma will prove refractory to frontline therapy or relapse subsequently. Traditional second-line chemotherapy regimens including ifosfamide, carboplatin, and etoposide (ICE) result in complete response rates of ~50%. Achievement of complete metabolic response (CMR) assessed by PET/CT imaging prior to autologous hematopoietic stem cell transplant (AHSCT) predicts favorable progression free survival (PFS) and overall survival (OS). PD-1 blockade is a well-established therapeutic strategy for the treatment of cHL. Pembrolizumab (PEM) is a checkpoint inhibitor targeting PD-1 currently FDA approved as monotherapy in relapsed cHL. We hypothesized that PEM in combination with ICE (PEM-ICE) chemotherapy would be a safe and effective regimen that would yield high CMR rates prior to AHSCT. Methods: This single arm, phase II, multi-institutional clinical trial evaluated the addition of PEM to ICE chemotherapy in AHSCT eligible patients with relapsed and refractory cHL (NCT03077828). The regimen consisted of 21 day cycles of PEM 200 mg IV on day 1 with standard ICE including ifosfamide 5 g/m2 with MESNA as a 24hr continuous infusion on day 2, carboplatin AUC 5 IV (max 800 mg) on day 2, and etoposide 100 mg/m2/day IV on days 1 to 3. Two cycles of PEM-ICE were followed by stem cell mobilization/collection. One cycle of PEM 200 mg IV monotherapy was then administered. Our primary endpoint was the rate of CMR on PET/CT (PET2) imaging defined as a Deauville score of ≤ 3. Images were reviewed centrally. An optional third cycle of PEM-ICE was permitted for patients achieving CMR to allow for appropriate timing of AHSCT. Secondary objectives included clinical outcomes (PFS and OS), safety and tolerability, and transplantation related metrics including ability to collect stem cells and time to engraftment. Results: A total of 42 patients were enrolled with 37 patients evaluable for the primary endpoint. Median age was 34 (19-70) with female predominance (n=27, 64%). 16 patients had primary refractory disease. The CMR rate assessed by PET/CT imaging following 2 cycles of PEM-ICE was 86.5% (95% CI, 71.2-95%), meeting our primary endpoint of improvement over historical outcomes to 70%. The PET2 ORR was 97.3% with 11% PR and 2.7% PD. PET2 scores were Deauville 1 in 45% (n=17), Deauville 2 in 27.0% (n=10), Deauville 3 in 8.1% (n=3), Deauville 4 in 13.5% (n=5), and Deauville 5 in 5.4% (n=2). New areas of PET-positivity in two cases were biopsied showing noncaseating granuloma in one case and EBV but no cHL in another. Five patients received the optional third cycle of PEM-ICE chemotherapy with 35 of the 37 evaluable patients proceeding to AHSCT. Seven patients had radiation as part of the conditioning regimen with an additional 4 patients receiving consolidative radiation following transplant. After a median follow up of 27 months, the median PFS was 26.9 months with survival probability at 24 months of 88.2% (Figure 1). Median OS was not reached with too few events but remained 95.1% at 27 months. The addition of PEM to ICE did not impair stem cell mobilization and all patients successfully collected, with 35 (87%) within 2 apheresis sessions (range 1-7). No patients had engraftment delays or failure. Of the 42 patients, all received at least one dose of PEM and were therefore eligible for toxicity analyses. 34 patients (81%) experienced adverse events (AEs) attributed to PEM and 22 patients (52.3%) had grade 3-4 AEs comprised of cytopenias, elevated AST/ALT, hyponatremia, hypophosphatemia, and fatigue. Five patients had severe AEs attributed to PEM which included anemia, back pain, decreased EF, fever, and thrombocytopenia. There were no significant PEM-related autoimmune events that delayed a patient's treatment on protocol. There were two grade 5 toxicities on the protocol including a patient with cardiac arrest during stem cell collection and a patient with acute respiratory distress syndrome attributed to engraftment syndrome. Both were judged "possibly" related to PEM. Conclusions: Pembrolizumab with ICE chemotherapy is a tolerable and efficacious regimen with high CMR rate as assessed by PET/CT. Despite short follow up, patients had excellent PFS and OS in the post-transplant setting. The results support further investigation of PEM-ICE as second-line treatment for AHSCT eligible patients with relapsed and refractory classical Hodgkin lymphoma. Figure 1 Figure 1. Disclosures Casulo: BMS: Research Funding; Verastem: Research Funding; Genentech: Research Funding; Gilead: Research Funding. Allen: Kyowa Kirin: Consultancy, Honoraria, Research Funding; Daichii Sankyo: Consultancy, Honoraria; Secure Bio: Consultancy, Honoraria. Karmali: Epizyme: Consultancy; AstraZeneca: Speakers Bureau; Roche: Consultancy; Genentech: Consultancy; EUSA: Consultancy; Janssen/Pharmacyclics: Consultancy; Karyopharm: Consultancy; Morphosys: Consultancy, Speakers Bureau; BeiGene: Consultancy, Speakers Bureau; Kite, a Gilead Company: Consultancy, Research Funding, Speakers Bureau; BMS/Celgene/Juno: Consultancy, Research Funding; Takeda: Research Funding. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. Winter: Actinium Pharma: Consultancy; BMS: Other: Husband: Data and Safety Monitoring Board; Karyopharm (Curio Science): Honoraria; Novartis: Other: Husband: Consultancy, Data and Safety Monitoring Board; Merck: Consultancy, Honoraria, Research Funding; Ariad/Takeda: Other: Husband: Data and Safety Monitoring Board; Epizyme: Other: Husband: Data and Safety Monitoring Board; Agios: Other: Husband: Consultancy; Gilead: Other: Husband: Consultancy; Janssen: Other: Husband: Consultancy. OffLabel Disclosure: new combination of study agent with standard of care chemotherapy regimen

BACKGROUND: Maintenance rituximab in MCL has improved survival and supports the exploration of maintenance with novel targeted agents. Ibrutinib is a BTK inhibitor approved for relapsed/refractory MCL. We report the final analysis of safety and efficacy of Ibrutinib maintenance (I-M) as monotherapy following chemo-immunotherapy induction for treatment-naive MCL in a multicenter phase II trial. METHODS: Pts with CR/PR to frontline chemo-immunotherapy (+/- autologous stem cell transplant (autoSCT)) received I-M 560 mg daily for up to 4 years. The primary endpoint was 3-year PFS rate. Secondary endpoints were to determine PR to CR conversions, median OS and the safety profile of I-M. Minimal residual disease (MRD) was measured using an NGS-MRD assay on peripheral blood (detection resolution of 1 cell per million; clonoSEQ®; Adaptive Biotechnologies) prior to and 1, 6 and 18-24 mo(s) after initiation of I-M. RESULTS: 36 pts were enrolled to complete accrual. Median age was 60 years (range 46-90). For induction, most pts were treated with BR (n=17, 47%) or a cytarabine-containing regimen (n=18, 50%). Eighteen (50%) pts underwent autoSCT. Thirty-four (94%) and 2 (6%) had CR and PR as best response to induction respectively, with 1 PR to CR conversion on I-M. At a median follow-up of 47 months, 10 (28%) pts completed a full I-M course, 7 (19%) remain on I-M, 15 (42%) discontinued I-M for treatment related adverse events (TRAEs) and 4 (11%) discontinued I-M for other reasons (PD x 1, secondary malignancies requiring treatment x 2, death cause unknown x 1). Three pts died during I-M, 2 deaths deemed unrelated to I-M (aspiration pneumonia, 2 nd malignancy) and 1 from unknown cause; 1 pt was lost to follow-up. Four pts were treated with rituximab maintenance after stopping I-M prematurely for toxicity without evidence of disease progression prior to or after change in therapy. At the time of data cut-off, MRD was assessed in 22 of 36 pts (available samples) at varying time points (Fig 1) with a dominant clone identified in all 22 pts. Pts were deemed MRD (-) if no sequences were detected at a threshold of 10 -6. Seventeen pts were MRD (-), 4 MRD indeterminate and 1 MRD (+) with radiographic CR after induction; the latter remained MRD (+) at 18 months with CR. All MRD indeterminate pts were MRD (-) when checked after 1 month on I-M. Six pts MRD (-) post-induction became MRD (+) during their I-M course. Of these pts, 2 reverted to MRD (-) with continued I-M; of the remaining 4 pts, 1 had PD and the others maintain stable clinical responses with ongoing I-M though MRD has not been rechecked. 3-year PFS and OS rates were 91% and 94% respectively (Figure 2A, B). PFS was improved in pts who received autoSCT prior to enrollment (Fig 2C, p=0.03) with a trend for improved OS (Figure 2D, p=0.057). MRD did not correlate with PFS (p=0.65) and OS (p=0.45) given few events. Atrial fibrillation/flutter occurred in 10 pts (28%; G1-2 n=7, 19%, G≥3 n = 3, 8%), 8 (22%) with new onset and 2 (6%) with worsening grade. HTN occurred in 20 pts (55%; G1-2 n=13, 33%, G≥3 n = 7, 22%), 15 (42%) with new onset and 5 (14%) with worsening grade. Incidences of both atrial fibrillation/flutter and HTN increased over time with ongoing I-M exposure (Table). Four pts had a 2 nd solid malignancy, 2 while on treatment and 2 after stopping I-M. TRAEs led to permanent dose reductions in 8 (22%) pts, 2 for neutropenia, 2 for fatigue, 2 for myalgias, 1 each for diarrhea and mucositis. Fifteen (42%) pts permanently discontinued I-M, most commonly for atrial fibrillation/flutter (n=8, 22%; n=5, 14% for G1-2). CONCLUSION: I-M 560 mg daily after response to frontline chemo-immunotherapy is feasible in MCL and results in durable PFS and OS. Toxicities including rates of high-grade atrial fibrillation/flutter and HTN are consistent with ibrutinib's known safety profile with increased incidence with longer exposure; discontinuation of I-M for atrial fibrillation/flutter in 22% of pts is higher than expected. Changes in NGS-MRD were noted in a small number of pts during maintenance. Extended follow-up and correlation of changes in MRD with PFS and OS are needed to determine clinical relevance of I-M and MRD status. Further studies evaluating maintenance with next generation BTK inhibitors as alternatives to ibrutinib should be explored to mitigate toxicity. Figure 1 Figure 1. Disclosures Karmali: Takeda: Research Funding; Genentech: Consultancy; Roche: Consultancy; Epizyme: Consultancy; Morphosys: Consultancy, Speakers Bureau; BeiGene: Consultancy, Speakers Bureau; Janssen/Pharmacyclics: Consultancy; BMS/Celgene/Juno: Consultancy, Research Funding; AstraZeneca: Speakers Bureau; Karyopharm: Consultancy; Kite, a Gilead Company: Consultancy, Research Funding, Speakers Bureau; EUSA: Consultancy. Abramson: Seagen Inc.: Research Funding; Allogene Therapeutics: Consultancy; Astra-Zeneca: Consultancy; Incyte Corporation: Consultancy; BeiGene: Consultancy; Kymera: Consultancy; Bluebird Bio: Consultancy; Genmab: Consultancy; EMD Serono: Consultancy; Bristol-Myers Squibb Company: Consultancy, Research Funding; Novartis: Consultancy; Kite Pharma: Consultancy; Morphosys: Consultancy; C4 Therapeutics: Consultancy; AbbVie: Consultancy; Karyopharm: Consultancy; Genentech: Consultancy. Stephens: JUNO: Research Funding; Abbvie: Consultancy; Adaptive: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Innate Pharma: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; AstraZeneca: Consultancy; CSL Behring: Consultancy; Celgene: Consultancy; Mingsight: Research Funding; Arqule: Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Epizyme: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding. Winter: Ariad/Takeda: Other: Husband: Data and Safety Monitoring Board; Actinium Pharma: Consultancy; BMS: Other: Husband: Data and Safety Monitoring Board; Gilead: Other: Husband: Consultancy; Janssen: Other: Husband: Consultancy; Epizyme: Other: Husband: Data and Safety Monitoring Board; Agios: Other: Husband: Consultancy; Novartis: Other: Husband: Consultancy, Data and Safety Monitoring Board; Merck: Consultancy, Honoraria, Research Funding; Karyopharm (Curio Science): Honoraria. Ma: Juno: Research Funding; Beigene: Research Funding, Speakers Bureau; AstraZeneca: Honoraria, Research Funding, Speakers Bureau; Loxo: Research Funding; Janssen: Research Funding, Speakers Bureau; Abbvie: Honoraria, Research Funding; TG Therapeutics: Research Funding; Pharmacyclics: Research Funding, Speakers Bureau. Petrich: Daiichi-Sankyo: Current Employment; Abbvie: Ended employment in the past 24 months. Hochberg: Leuko: Consultancy; Trapelo Health: Consultancy. Kuhr: Adaptive Biotechnologies: Current Employment. Lee: Adaptive Biotechnologies: Current Employment. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. OffLabel Disclosure: We will report on the use of ibrutinib maintenance after front-line induction therapy in MCL.

Background : LBCLs are prevalent and aggressive subtypes of NHL, with limited treatment options and historically poor outcomes in the third- or later-line setting. Liso-cel is an autologous, CD19-directed, defined composition, 4-1BB CAR T cell product administered at equal target doses of CD8 + and CD4 + CAR + T cells. TRANSCEND NHL 001 (NCT02631044) is a seamless design, pivotal, phase 1 study evaluating liso-cel in patients (pts) with R/R LBCLs (Abramson et al. Lancet 2020). We present 2-year follow-up data from the LBCL cohort. Methods: Pts ≥ 18 years of age with R/R DLBCL not otherwise specified (NOS, including de novo and transformed from any indolent lymphoma), high-grade B-cell lymphoma (HGBCL) with MYC and BCL2 and/or BCL6 rearrangements, primary mediastinal B-cell lymphoma (PMBCL), or follicular lymphoma grade 3B (FL3B) after ≥ 2 lines of therapy and with ECOG PS 0-2 were eligible. Pts with grade 3 or 4 cytopenias, mild to moderate organ dysfunction, and secondary CNS lymphoma were allowed. Bridging therapy was allowed at clinician discretion but reconfirmation of PET-positive disease was required before lymphodepletion with fludarabine and cyclophosphamide. Primary endpoints were treatment-emergent AEs (TEAE) and ORR. Key secondary endpoints were CR rate, duration of response (DOR), PFS, and OS. TEAEs, including investigator-identified neurological events (NE) related to liso-cel, were graded using NCI CTCAE v4.03; cytokine release syndrome (CRS) was graded per Lee 2014 criteria in the liso-cel-treated set (all pts who received ≥ 1 dose of liso-cel). ORR was assessed by an independent review committee (IRC) per Lugano 2014 criteria in the efficacy-evaluable set (all pts with confirmed PET-positive disease who received ≥ 1 dose of liso-cel). Pts were followed for 2 years after the last dose of liso-cel and were then asked to enroll in a separate long-term follow-up study for up to 15 years (NCT03435796). Results: A total of 345 pts underwent leukapheresis. In the liso-cel-treated set (N = 270), median age was 63 years (range, 18-86); 41% of pts were ≥ 65 years of age. Histologies included DLBCL NOS (de novo, 51%; transformed from indolent lymphoma, 29%), HGBCL (13%), PMBCL (6%), and FL3B (1%). Seven pts (3%) had secondary CNS lymphoma. Pts received a median of 3 prior lines of systemic therapy (range, 1-8) and 33% had prior autologous HSCT (prior allogeneic HSCT, 3%). Of all pts, 67% were chemotherapy refractory, 45% had never achieved CR, and 59% received bridging therapy. As of the Jan 4, 2021 data cut, study is ongoing; 268 pts had ≥ 24 months (mo) of follow-up, died, or withdrew from the study. Responses per IRC (ORR, 73%; CR rate, 53%) in the efficacy-evaluable set (N = 257) were durable with a median (95% CI) DOR of 23.1 mo (8.6-not reached), median PFS of 6.8 mo (3.3-12.7), and median OS of 27.3 mo (16.2-45.6) (Table). At 24 mo, the probabilities (95% CI) of continued response, PFS, and OS were 49.5% (41.4%-57.0%), 40.6% (34.0%-47.2%), and 50.5% (44.1%-56.5%), respectively. During the 90-day treatment-emergent (TE) reporting period, 79% of pts in the liso-cel-treated set (N = 270) had grade ≥ 3 TEAEs; 45% had serious TEAEs. CRS and NE of any grade occurred in 42% and 30% of pts, respectively (grade 3-4 CRS, 2%; grade 3-4 NE, 10%). Median (range) time to onset of CRS and NE was 5 (1-14) and 9 (1-66) days, respectively. Grade ≥ 3 infections and laboratory-based prolonged cytopenia at Day 29 occurred in 12% and 37% of pts, respectively. In the post-TE (Day 91 to end of study) reporting period, which included 17 pts who received liso-cel re-treatment, 23% of pts in the liso-cel-treated set (N = 249) had grade ≥ 3 AEs and 17% had serious AEs. The most common grade ≥ 3 AEs in the post-TE period were neutropenia (7%), anemia (6%), thrombocytopenia (4%), and febrile neutropenia (4%). Grade ≥ 3 infections occurred in 5% of pts. In the post-TE period, 100 pts (37% of all pts) died, mostly due to disease progression (86% of all post-TE deaths; 32% of all pts). CAR T cells were present in peripheral blood for up to 4 years. Conclusions: Liso-cel demonstrated durable remissions with estimated 2-year DOR and PFS rates of 49.5% and 40.6%, respectively, and a favorable safety profile in the extended follow-up analysis of this large CAR T cell study in R/R LBCLs. Most CAR T cell-associated AEs occurred within the initial 90-day TE reporting period. No new safety signals were observed during long-term follow-up. Figure 1 Figure 1. Disclosures Abramson: Genmab: Consultancy; Kite Pharma: Consultancy; C4 Therapeutics: Consultancy; Bristol-Myers Squibb Company: Consultancy, Research Funding; Kymera: Consultancy; Bluebird Bio: Consultancy; EMD Serono: Consultancy; Novartis: Consultancy; Morphosys: Consultancy; BeiGene: Consultancy; Allogene Therapeutics: Consultancy; Astra-Zeneca: Consultancy; Incyte Corporation: Consultancy; Seagen Inc.: Research Funding; AbbVie: Consultancy; Karyopharm: Consultancy; Genentech: Consultancy. Palomba: Rheos: Honoraria; Novartis: Consultancy; Lygenesis: Honoraria; Priothera: Honoraria; Juno: Patents & Royalties; Notch: Honoraria, Other: Stock; Pluto: Honoraria; Seres: Honoraria, Other: Stock, Patents & Royalties, Research Funding; Magenta: Honoraria; WindMIL: Honoraria; Kite: Consultancy; Ceramedix: Honoraria; Nektar: Honoraria; Wolters Kluwer: Patents & Royalties; PCYC: Consultancy; BeiGene: Consultancy. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. Lunning: Myeloid Therapeutics: Consultancy; Spectrum: Consultancy; TG Therapeutics: Consultancy; AbbVie: Consultancy; Morphosys: Consultancy; Karyopharm: Consultancy; Beigene: Consultancy; Daiichi-Sankyo: Consultancy; Novartis: Consultancy; Kyowa Kirin: Consultancy; Legend: Consultancy; Janssen: Consultancy; ADC Therapeutics: Consultancy; Acrotech: Consultancy; Verastem: Consultancy; Celgene, a Bristol Myers Squibb Co.: Consultancy; AstraZeneca: Consultancy; Kite, a Gilead Company: Consultancy. Wang: Molecular Templates: Research Funding; BGICS: Honoraria; Miltenyi Biomedicine GmbH: Consultancy, Honoraria; Oncternal: Consultancy, Research Funding; Bayer Healthcare: Consultancy; Physicians Education Resources (PER): Honoraria; InnoCare: Consultancy, Research Funding; CAHON: Honoraria; OMI: Honoraria; Loxo Oncology: Consultancy, Research Funding; The First Afflicted Hospital of Zhejiang University: Honoraria; Lilly: Research Funding; Scripps: Honoraria; AstraZeneca: Consultancy, Honoraria, Research Funding; Clinical Care Options: Honoraria; Celgene: Research Funding; Imedex: Honoraria; Pharmacyclics: Consultancy, Research Funding; Chinese Medical Association: Honoraria; Mumbai Hematology Group: Honoraria; Dava Oncology: Honoraria; Moffit Cancer Center: Honoraria; Epizyme: Consultancy, Honoraria; DTRM Biopharma (Cayman) Limited: Consultancy; Genentech: Consultancy; CStone: Consultancy; Kite Pharma: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Anticancer Association: Honoraria; BeiGene: Consultancy, Honoraria, Research Funding; Hebei Cancer Prevention Federation: Honoraria; Newbridge Pharmaceuticals: Honoraria; Juno: Consultancy, Research Funding; BioInvent: Research Funding; VelosBio: Consultancy, Research Funding; Acerta Pharma: Consultancy, Honoraria, Research Funding. Arnason: Juno/BMS: Honoraria. Maloney: Janssen: Honoraria; MorphoSys: Honoraria; Novartis: Honoraria; Celgene: Honoraria, Other: Rights to royalties from Fred Hutchinson Cancer Research Center for patents licensed to Juno Therapeutics/Bristol Myers Squibb; BMS: Honoraria, Other: Rights to royalties from Fred Hutchinson Cancer Research Center for patents licensed to Juno Therapeutics/Bristol Myers Squibb; Amgen: Honoraria; Celgene: Other: Research funding was paid to my institution, Research Funding; Juno therapeutics: Other: Research funding was paid to my institution, Research Funding; Kite Pharma: Honoraria, Other: Research funding was paid to my institution, Research Funding; Navan Technologies: Honoraria, Other: Stock options; A2 Biotherapeutics: Honoraria, Other: Stock options; Umoja: Honoraria; Genentech: Honoraria; Legend Biotech: Honoraria; Juno Therapeutics: Honoraria, Other: Rights to royalties from Fred Hutchinson Cancer Research Center for patents licensed to Juno Therapeutics/Bristol Myers Squibb. Andreadis: Merck: Research Funding; BMS: Research Funding; CRISPR Therapeutics: Research Funding; GenMAB: Research Funding; Novartis: Research Funding; Roche: Current equity holder in publicly-traded company, Ended employment in the past 24 months; Epizyme: Honoraria; Incyte: Honoraria; TG Therapeutics: Honoraria; Kite: Honoraria; Karyopharm: Honoraria; Atara: Consultancy, Honoraria. Sehgal: Juno/Celgene: Research Funding; Kite/Gilead: Research Funding. Ghosh: Bristol Myers Squibb: Consultancy, Honoraria, Research Funding, Speakers Bureau; Genentech: Research Funding; Karyopharma: Consultancy, Honoraria; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; Genmab: Consultancy, Honoraria; Epizyme: Honoraria, Speakers Bureau; Seattle Genetics: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Incyte: Consultancy, Honoraria; TG Therapeutics: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; ADC Therapeutics: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; Adaptive Biotech: Consultancy, Honoraria; AbbVie: Honoraria, Speakers Bureau. Kostic: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Kim: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Ogasawara: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Dehner: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Siddiqi: BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Juno Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics LLC, an AbbVie Company: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; TG Therapeutics: Research Funding; Kite Pharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BeiGene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Speakers Bureau; Oncternal: Research Funding.

Background: Anti-CD19 chimeric antigen receptor T-cell therapy (CART) is a highly active therapy for relapsed/refractory (R/R) aggressive B-cell lymphoma. Nonetheless, most patients (pts) ultimately develop progressive disease (PD). There is little guidance on the optimal treatment approach(es) for these pts. We performed a multicenter retrospective analysis with a primary objective to assess treatment patterns and outcomes in pts with R/R aggressive B-cell lymphoma who develop PD after anti-CD19 CARTs. Methods: Pts with aggressive B-cell lymphoma treated with anti-CD19 CART between 2015 and 2020 across 12 US academic medical centers were included. Demographic and clinical characteristics were collected along with CART toxicities and response. Regimens administered as salvage post CART were assessed. Univariate analyses (UVA) were performed to determine impact of demographic and clinical variables on survival outcomes. All p-values were two-tailed. Survival curves were calculated using the Kaplan-Meier method. Results: A total of 400 pts received anti-CD19 CARTs and were included for analysis. For the entire cohort: median PFS and OS from time of CART infusion were 11 months [mo] and 27 mo respectively. On log-rank testing, pts who received ≥3 lines of pre-CART therapy and those with refractory disease pre-CART had significantly worse PFS (p=0.004 & 0.001) and OS (both p With median follow-up 22.4 mo, 190 pts (48%) had PD after CART; demographic and clinical variables of pts with and without PD are detailed in Table 1. Biopsy to confirm PD and assess CD19 status was done in 69 pts (36%) with CD19 negative relapse seen in 11 (16%). Of pts with PD, median PFS and OS from time of PD was 83 days (in pts who received salvage) and 174 days (for all PD pts) respectively. Pts with PD were more likely to have elevated LDH (p=0.001) and extranodal disease (p=0.003) at apheresis. For pts with PD after CART: 125 (65.5%) received further therapies. Pts were more likely to receive salvage therapies if their best response to CART was CR (p=0.026) or PR (p=0.015). Response rates of select first- and second-line therapies and PFS of first line therapies received after CART failure are detailed in figure 1. ORR and CRs were highest for polatuzumab, bendamustine, & rituximab (pola-BR; 73% & 40%), followed by BTK inhibitors (BTKi; 50% & 38%), and bispecific antibodies (bsAb) (50% & 25%). Five of 7 pts who received a BTKi had non-germinal center (GC) cell of origin (COO; 1 unknown COO). On log-rank testing, pts with elevated LDH (p=0.003) at time of apheresis and those with intermediate/high IPI (p=0.013) had inferior PFS with first salvage regimens. Median PFS was highest for pola-BR (4.5 mo, n=14), followed by bsAb (2.5 mo, n=8), lenalidomide +/- anti-CD20 antibody (1.8 mo, n=13), checkpoint inhibitors (CPI; 1.6 mo, n=10), BTKi (1.2 mo, n=8), radiation alone (1.2 mo; n=17), chemotherapy (1.1 mo, n=12), and tafasitamab + lenalidomide (0.9 mo, n=5). Median PFS for all treated pts was 1.8 mo. OS from start of first salvage regimen was highest for CPI (OS 12.4 mo, n=10), followed by pola-BR (8.9 mo, n=14), BTKi (8.8 mo, n=8), lenalidomide +/- anti-CD20 (8.7 mo, n=13), radiation alone (7.1 mo, n =17), bsAb (5.9 mo, n=8), chemotherapy (5.4 mo, n=12), and tafasitamab + lenalidomide (1.2 mo, n=5). 12 pts (6.3%) later received an allogeneic hematopoietic cell transplant (alloHCT). In alloHCT pts at last follow-up, 10 were evaluable for response: 7 had CR and 5 remain in CR. Clinical characteristics of pts who received alloHCT are detailed in table 2. Notably, median age was 59 years (41-68), 1 (8.3%) had a prior alloHCT, and 6 (50%) had prior autologous HCT. The majority had CR or PR as best response to CART (CR n=6, 50%; PR n=3, 25%), and only 1 pt (8.3%) with PD as best response to CART was salvaged with alloHCT. Conclusions: This is the largest reported analysis to date of pts with aggressive B-cell lymphoma who develop PD post-CART. The highest ORRs were with pola-BR, bsAb, and BTKi as first line of salvage. High response rates with BTKi may be attributed to non-GC COO in the majority of treated pts and perhaps a beneficial immunomodulatory effect on previously administered CARTs. AlloHCT remains a potential curative therapy for select pts with over half with durable remission; however, few ultimately received alloHCT. Despite increased use of novel therapies, survival in pts who progress after CART is still dismal warranting more effective therapies. Figure 1 Figure 1. Disclosures Epperla: Genzyme: Honoraria; Karyopharm: Other: Ad Board; Beigene: Speakers Bureau; Verastem: Speakers Bureau. Torka: TG Therapeutics: Membership on an entity's Board of Directors or advisory committees. Hess: ADC Therapeutics: Consultancy; BMS: Speakers Bureau. Cohen: Janssen, Adicet, Astra Zeneca, Genentech, Aptitude Health, Cellectar, Kite/Gilead, Loxo, BeiGene, Adaptive: Consultancy; Genentech, BMS/Celgene, LAM, BioINvent, LOXO, Astra Zeneca, Novartis, M2Gen, Takeda: Research Funding. Ma: Abbvie: Honoraria, Research Funding; Beigene: Research Funding, Speakers Bureau; Loxo: Research Funding; Juno: Research Funding; AstraZeneca: Honoraria, Research Funding, Speakers Bureau; Janssen: Research Funding, Speakers Bureau; TG Therapeutics: Research Funding; Pharmacyclics: Research Funding, Speakers Bureau. Winter: Gilead: Other: Husband: Consultancy; Janssen: Other: Husband: Consultancy; Ariad/Takeda: Other: Husband: Data and Safety Monitoring Board; Epizyme: Other: Husband: Data and Safety Monitoring Board; Agios: Other: Husband: Consultancy; Actinium Pharma: Consultancy; BMS: Other: Husband: Data and Safety Monitoring Board; Merck: Consultancy, Honoraria, Research Funding; Novartis: Other: Husband: Consultancy, Data and Safety Monitoring Board; Karyopharm (Curio Science): Honoraria. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. Danilov: Bayer Oncology: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Honoraria, Research Funding; Rigel Pharm: Honoraria; Takeda Oncology: Research Funding; TG Therapeutics: Consultancy, Research Funding; Abbvie: Consultancy, Honoraria; Beigene: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; SecuraBio: Research Funding; Astra Zeneca: Consultancy, Honoraria, Research Funding; Bristol-Meyers-Squibb: Honoraria, Research Funding; Gilead Sciences: Research Funding. Stephens: Adaptive: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Epizyme: Membership on an entity's Board of Directors or advisory committees; JUNO: Research Funding; Mingsight: Research Funding; CSL Behring: Consultancy; Novartis: Research Funding; Abbvie: Consultancy; AstraZeneca: Consultancy; Arqule: Research Funding; Celgene: Consultancy; Innate Pharma: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding. Shah: Miltenyi Biotec: Consultancy, Honoraria, Research Funding; Umoja: Consultancy; Incyte: Consultancy; Kite: Consultancy; Legend: Consultancy; Epizyme: Consultancy; Lily: Consultancy, Honoraria, Research Funding. Shouse: Beigene Pharmaceuticals: Honoraria; Kite Pharmaceuticals: Speakers Bureau. Barta: Acrotech: Honoraria; Daiichi Sankyo: Honoraria; Seagen: Honoraria; Kyowa Kirin: Honoraria. Karmali: Karyopharm: Consultancy; EUSA: Consultancy; Roche: Consultancy; Janssen/Pharmacyclics: Consultancy; Genentech: Consultancy; Morphosys: Consultancy, Speakers Bureau; Epizyme: Consultancy; Kite, a Gilead Company: Consultancy, Research Funding, Speakers Bureau; BMS/Celgene/Juno: Consultancy, Research Funding; AstraZeneca: Speakers Bureau; Takeda: Research Funding; BeiGene: Consultancy, Speakers Bureau.

Background: Mantle cell lymphoma (MCL) is an aggressive subtype of B-cell non-Hodgkin lymphoma (NHL). Most patients with MCL relapse after first-line immunochemotherapy, with poor responses to salvage therapy. Chimeric antigen receptor (CAR) T cell therapy has shown clinical efficacy in patients with relapsed/refractory (R/R) NHL. We report the results of the dose-finding and dose-expansion parts of the ongoing phase 1 TRANSCEND NHL 001 study (NCT02631044) in patients with R/R MCL (MCL cohort) who received lisocabtagene maraleucel (liso-cel), an investigational, CD19-directed, defined composition, 4-1BB CAR T cell product administered at equal target doses of CD8+ and CD4+ CAR+ T cells. Methods: Eligible patients had confirmed MCL (cyclin D1 expression, t[11;14]) with R/R disease after ≥1 prior line of therapy. After lymphodepleting chemotherapy, patients received liso-cel infusion at 1 of 2 dose levels (DLs): DL1 (50 × 106 CAR+ T cells) or DL2 (100 × 106 CAR+ T cells). Bridging therapy was allowed between leukapheresis and initiation of lymphodepleting chemotherapy. Primary endpoints were safety and objective response rate (ORR). Secondary endpoints included complete response (CR) rate, duration of response, progression-free survival, overall survival, and pharmacokinetics (PK). Results: At data cutoff, 41 patients had undergone leukapheresis and 32 had received liso-cel (DL1, n = 6; DL2, n = 26). Among the 32 patients who received liso-cel, the median (range) age was 67 (36‒80) years and 27 patients (84%) were male. Twelve patients (37.5%) had blastoid morphology, 23 (72%) had documented Ki67 ≥30%, 7 (22%) had a TP53 mutation, and 11 (34%) had a complex karyotype. Patients had a median (range) sum of the product of perpendicular diameters before lymphodepleting chemotherapy of 28.7 (0-209.6) cm2 and median lactate dehydrogenase of 251.5 (117-811) U/L. Patients had received a median (range) of 3 (1-7) prior systemic therapies, and most (72%) were refractory to their last prior therapy. Of 28 patients (87.5%) who had received a prior Bruton tyrosine kinase inhibitor, 11 (34%) were refractory to the therapy. Seventeen patients (53%) received bridging therapy. Eighteen patients (56%) had serious treatment-emergent adverse events (TEAEs), and 27 (84%) had grade ≥3 TEAEs, primarily neutropenia (41%), anemia (34%), and thrombocytopenia (31%). Grade ≥3 thrombocytopenia was more frequent at DL2 (n = 9/26 [35%]) than at DL1 (n = 1/6 [17%]). Prolonged grade ≥3 cytopenias (present at study Day 29) occurred in 11 patients (34%). Sixteen patients (50%; DL1, n = 2/6 [33%]; DL2, n = 14/26 [54%]) had cytokine release syndrome (CRS), including 1 grade 4 event at DL2. There were no grade 3 or 5 CRS events. Median (range) time to CRS onset and resolution was 6 (2‒10) days and 4 (2‒9) days, respectively. Nine patients (28%) had neurological events (NEs), all at DL2, including 3 grade 3 NEs. No grade 4 or 5 NEs were reported. Median (range) time to NE onset and resolution was 8 (2‒25) days and 3 (1‒51) days, respectively. Ten patients (31%) received tocilizumab and/or corticosteroids for treatment of CRS and/or NEs. Grade 5 TEAEs occurred in 2 patients (at DL2): one patient with high tumor burden had tumor lysis syndrome and 1 patient had cryptococcal meningoencephalitis. DL2 was selected for dose expansion. Of 32 patients, 27 responded to liso-cel (ORR, 84%: DL1, n = 4/6 [67%]; DL2, n = 23/26 [88%]), and 19 (59%) achieved a CR (DL1, n = 2/6 [33%]; DL2, n = 17/26 [65%]). Among the 12 patients with blastoid morphology, 9 patients had a response (ORR, 75%), including 7 (58%) who achieved a CR. Overall, the median (range) time to first CR was 1 (1-6) month. At data cutoff, 20 (74%) of 27 responders were censored with an ongoing response or had completed the study. Median (range) follow-up duration was 10.9 (1.2-24.8) months for DL1 and 3.1 (0.4-23.0) months for DL2. Preliminary PK analysis indicated that median maximum expansion was higher among patients at DL2 than at DL1. Conclusions: In this phase 1 study of patients with R/R MCL, treatment with liso-cel was associated with a low incidence of grade ≥3 CRS and NEs, late onset of CRS/NEs, and promising clinical activity. Dose confirmation is ongoing at DL2 in the MCL cohort. Disclosures Palomba: Pharmacyclics: Honoraria; Juno: Honoraria; Celgene: Honoraria; Merck: Honoraria; Novartis: Honoraria; Regeneron: Research Funding; Juno: Research Funding; Genentech: Research Funding. Gordon:Zylem Biosciences: Patents & Royalties: Patents, No Royalties. Siddiqi:Juno: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; BeiGene: Other: DMC member; Juno Therapeutics, Pharmacyclics LLC, an AbbVie Company, AstraZeneca, Celgene, Kite Pharma, and BeiGene: Consultancy; Pharmacyclics LLC, an AbbVie Company, Seattle Genetics, Janssen, and AstraZeneca: Speakers Bureau; Pharmacyclics LLC, an AbbVie Company, Juno Therapeutics, KITE Pharma, AstraZeneca, TG Therapeutics, Celgene, Oncternal, and BeiGene: Research Funding; AstraZeneca: Other: Travel/accommodations/expenses; Astrazenca: Membership on an entity's Board of Directors or advisory committees; PCYC: Membership on an entity's Board of Directors or advisory committees. Abramson:Celgene: Honoraria, Other: Scientific Advisory Board; Juno Therapeutics: Other: Scientific Advisory Board; AbbVie: Other: Scientific Advisory Board; EMD Serono: Other: Scientific Advisory Board; Genentech/Roche: Other: Scientific Advisory Board; Janssen: Other: Scientific Advisory Board; Karyopharm: Other: Scientific Advisory Board; Gilead: Other: Scientific Advisory Board; Verastem: Other: Scientific Advisory Board; Bayer: Other: Scientific Advisory Board; Merck: Other; KIte Pharma: Other; Novartis: Other; Amgen: Other; Seattle Genetics: Other; Allogene: Other; Morphosys: Other; C4 Therapeutics: Other; BeiGene: Other; AstraZeneca: Honoraria; Incyte: Honoraria. Kamdar:Seattle Genetics: Speakers Bureau; Karyopharm: Consultancy; BMS: Consultancy; Abbvie: Consultancy; AstraZeneca: Consultancy; Pharmacyclics: Consultancy. Lunning:Acrotech: Consultancy; ADC Therapeutics: Consultancy; Bristol Meyers Squibb: Consultancy, Honoraria, Research Funding; Curis: Research Funding; Gilead: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Kite: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; TG Therapeutics: Research Funding; Verastem: Consultancy, Honoraria; AstraZeneca: Consultancy, Honoraria; Legend: Consultancy; Beigene: Consultancy, Honoraria; Aeratech: Consultancy, Honoraria. Maloney:Kite, a Gilead Company: Consultancy, Honoraria, Research Funding; MorphoSys: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Gilead Sciences: Consultancy, Honoraria; A2 Biotherapeutics: Consultancy, Current equity holder in publicly-traded company, Honoraria; Juno Therapeutics: Consultancy, Honoraria, Patents & Royalties: Patents are pending, but not issued, licensed, no royalties, no licensees., Research Funding; Bioline Rx: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding. Andreadis:Genentech: Other: Spouse Employee (salary and stock); Novartis: Research Funding; Celgene/Juno: Research Funding; Amgen: Research Funding; Merck: Research Funding; Gilead/Kite: Other: Advisor; Jazz Pharmaceuticals: Other: Advisor; Astellas: Other: Advisor; Seattle Genetics: Other: Advisor; Karyopharm: Other: Advisor; Incyte: Other. Arnason:Regeneron: Consultancy; Juno: Consultancy. Ghosh:Forty Seven Inc: Consultancy, Other: Research Bureau, Research Funding; Genmab: Consultancy, Speakers Bureau; AbbVie: Speakers Bureau; Karyopharm: Consultancy; Juno/Celgene/Bristol-Myers Squibb: Consultancy, Research Funding; Kite/Gilead: Consultancy, Speakers Bureau; AstraZeneca: Speakers Bureau; Roche/Genentech: Research Funding; SGN: Consultancy, Research Funding, Speakers Bureau; TG Therapeutics: Consultancy, Research Funding; Celgene/Bristol-Myers Squibb: Speakers Bureau; Janssen: Consultancy, Research Funding, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding, Speakers Bureau. Mehta:Innate Pharmaceuticals: Research Funding; Kite/Gilead: Research Funding; Merck: Research Funding; Gelgene/BMS: Research Funding; Oncotartis: Research Funding; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Juno Parmaceuticals/BMS: Research Funding; fortyseven Inc/Gilead: Research Funding; Takeda: Research Funding; Roche-Genentech: Research Funding; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Affimed: Research Funding. Farazi:Juno Therapeutics, a Bristol-Myers Squibb Company: Current Employment; Bristol-Myers Squibb: Current equity holder in publicly-traded company. Garcia:Juno Therapeutics, a Bristol-Myers Squibb Company: Current Employment; Bristol-Myers Squibb Company: Current equity holder in publicly-traded company. Dehner:Juno Therapeutics, a Bristol-Myers Squibb Company: Current Employment; Bristol-Myers Squibb: Current equity holder in publicly-traded company. Ogasawara:Bristol-Myers Squibb: Current Employment; Bristol-Myers Squibb: Current equity holder in publicly-traded company. Gao:Bristol-Myers Squibb: Current equity holder in publicly-traded company; Bristol-Myers Squibb: Current Employment. Wang:Juno: Consultancy, Research Funding; Acerta Pharma: Research Funding; Loxo Oncology: Consultancy, Research Funding; AstraZeneca: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; InnoCare: Consultancy; Kite Pharma: Consultancy, Other: Travel, accommodation, expenses, Research Funding; Pharmacyclics: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Janssen: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; MoreHealth: Consultancy; Lu Daopei Medical Group: Honoraria; Beijing Medical Award Foundation: Honoraria; OncLive: Honoraria; Molecular Templates: Research Funding; Verastem: Research Funding; Dava Oncology: Honoraria; Guidepoint Global: Consultancy; Pulse Biosciences: Consultancy; Celgene: Consultancy, Other: Travel, accommodation, expenses, Research Funding; Oncternal: Consultancy, Research Funding; Nobel Insights: Consultancy; OMI: Honoraria, Other: Travel, accommodation, expenses; Targeted Oncology: Honoraria; BioInvent: Research Funding; VelosBio: Research Funding.

Background Patients treated with chronic immunosuppression face a six-fold increase in their cumulative lifetime risk of lymphoma relative to age-matched immunocompetent counterparts. These malignances represent a spectrum of lymphoid and plasmacytic histologies collectively referred to as post-transplant lymphoproliferative disorders (PTLD). Accurate risk-stratification and optimal treatment strategies are unclear given wide histologic and clinical heterogeneity. Current standard-of-care models include immunosuppression reduction and sequential, response-adapted chemoimmunotherapy platforms, however 80% of patients will require chemotherapy exposure. Overall response rates (ORR) are >90%, however relapse is common and serious treatment-related toxicities including infection and allograft rejection pose significant challenges. Several risk-stratification schemes have been proposed to direct initial therapy and predict clinical outcomes, however their external validity has been inconsistent across patient populations. We report here the results of a single-center retrospective study assessing the treatment patterns and outcomes of patients diagnosed with PTLD and provide a risk-assessment profile that may help improve clinical outcomes. Methods Patients with a diagnosis of PTLD were identified by Electronic Medical Records database query. Inclusion criteria were: age ≥ 18 years at the time of diagnosis, confirmation of PTLD by internal pathology review, primary diagnosis from 2008-2018, and receipt of therapy and surveillance care at Northwestern University in Chicago, Illinois, USA. Exploratory univariate analyses were performed using Kaplan-Meier estimates with 95% confidence intervals and log-rank p-values for time-to-event outcomes; significance was set at p < 0.05. Response to treatment and disease progression were classified per provider-specific interpretations of clinical data as assessed by patient chart review. ORR is defined as complete or partial response. Progression-free survival (PFS) is defined as time from diagnosis to disease progression; patients who died before restaging or who were lost to follow-up were censored. Overall survival (OS) is defined as time from diagnosis to death from any cause; patients who were alive at last follow-up were censored. Results A total of 182 patients were identified by database query and 111 patients met our inclusion criteria. Demographics data are provided (Figure 1A). Five-year PFS and OS were 55.7% and 87.2%, respectively (Figure 1B). 92.6% of patients treated with immunosuppression agents underwent dose reduction and 16.8% experienced graft rejection, of which 27.8% required re-transplantation. Exploratory univariate analyses were performed on the following clinical factors: age, LDH, Ann-Arbor Stage, presence of extranodal disease, histologic EBER positivity, ECOG PS, comorbid conditions (type II diabetes, obesity, and coronary artery disease), CNS involvement, transplant type, presence of EBV viremia, and PTLD subtype. Established risk stratification models, including the IPI, R-IPI, Leblond score, Ghobrial score, and PTLD prognostic index, were applied to this cohort. We identified elevated LDH (p=0.04) and IPI score >3 (p=0.015) as predictors of PFS (Figure 1C); elevated LDH (p=0.02) and thoracic allograft transplantation (p=0.03) were predictors of OS (Figure 1D). The PTLD prognostic index significantly predicted PFS (p=0.03) and OS (p=0.013) (Figure 1E). 50.4% received Rituximab monotherapy prior to risk-stratification for combination chemoimmunotherapy; ORR and CR rates with Rituximab monotherapy were 67.9% and 41.1%, respectively. Overall response to Rituximab monotherapy was found to be a significant predictor of PFS (p Conclusions This study represents one of the largest retrospective cohorts of PTLD patients to date. We show that the PTLD prognostic index is the most accurate risk stratification tool in predicting PFS and OS in this patient population and may have utility in guiding therapeutic approaches in PTLD patients. LDH, IPI score, and type of allograft transplantation are significant clinical variables in predicting clinical outcomes. Furthermore, response to Rituximab monotherapy was a significant predictor of PFS; improving frontline outcomes to high-risk patients remains a critical unmet need. Figure Disclosures Winter: Epizyme: Other: DSMB; Delta Fly Pharma: Consultancy; Amgen: Consultancy; CVS/Caremark: Consultancy; Ariad/Takeda: Consultancy; Norvartis: Consultancy, Other: DSMB; Merck: Membership on an entity's Board of Directors or advisory committees, Other: advisory board; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: advisory board. Gordon:Zylem Biosciences: Patents & Royalties: Patents, No Royalties. Karmali:BeiGene: Speakers Bureau; BMS/Celgene/Juno: Honoraria, Other, Research Funding, Speakers Bureau; Gilead/Kite: Honoraria, Other, Research Funding, Speakers Bureau; Takeda: Research Funding; Karyopharm: Honoraria; AstraZeneca: Speakers Bureau. Ma:AbbVie: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; BeiGene: Honoraria, Research Funding, Speakers Bureau; Bioverativ: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Kite: Consultancy, Honoraria; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; Juno: Research Funding; Novartis: Research Funding; TG Therapeutics: Research Funding. Ganger:Mallinkrodt: Consultancy; Gilead: Speakers Bureau. Pro:Verastem Oncology: Research Funding.

Introduction: Although radiation therapy (RT) has limited clinical efficacy for advanced stage lymphoma, RT has been used as a method for in situ vaccination to generate an abscopal effect. Frank et al. combined low dose RT with class C CpG deoxynucleotides (CpGs) for the treatment of advanced stage indolent lymphoma (Cancer Discovery, 2018). CpGs are toll-like receptor 9 agonists and activates the innate immune system. The overall response rate was high (89.6%) in this trial but only 7 of 29 patients (pts) (24%) had partial response and 1 had a complete response (3%). Unlike external beam RT, photothermal therapy (PTT) using gold nanoparticles (AuNPs) can generate a strong in situ vaccination effect by heat ablation of tumors (Bear et al. PLOS One, 2013). (Figure 1A) The ablation induced increased CD8 T cell infiltration in non-treated tumors and dendritic cell maturation in the draining lymph nodes, but it also increased systemic immune suppression via increased myeloid suppressor cells (MDSCs) in a melanoma model. MDSCs differentiate into active macrophages when stimulated by CpGs. Other PTT methods have been evaluated in combination with check-point inhibitors with success in solid tumor murine models (Liu et al. Immunotherapy 2018; Chen et al. Nature Comm. 2016). Therefore, we hypothesized that PTT in combination with CpG can elicit a stronger the in situ vaccination effect compared with RT with CpG in a murine lymphoma model. Methods: PTT is achieved by exciting branched AuNP (BNP) with a near infrared (NIR) laser (808nm). For the dual lymphoma model, A20 lymphoma cells in Matrigel were injected into the right flank of BALB/c mice to establish a primary tumor. Three days later, a secondary tumor was established in the left flank. When the tumor reached 5 mm in diameter, PTT with CpG (sequence 2395) or RT (10Gy) with CpG of the primary tumor were performed. Control groups included PTT without CpG, CpG only, BNP with CpG without PTT, and PBS. Sixteen days after PTT or RT, mice are euthanized and flow cytometry was performed on the primary tumor, secondary tumor, spleen, and draining lymph nodes and analyzed for T cells and dendritic cells (DC). Results: Within 5 minutes after PTT, the temperature of the treated primary tumor reached almost 60°C. The primary tumor growth was inhibited for both RT/CpG and PTT/CpG treatment groups compared with the PBS control group. RT/CpGs treated primary tumors demonstrated re-growth 14 days (D14) after treatment while PTT/CpG treated tumors did not (p Conclusion: Overall, we demonstrated as a proof-of-concept that PTT/CpG generated a stronger in situ vaccination effect when compared with RT/CpG therapy in lymphoma. In addition, we have described the immune responses after PTT in combination with CpG in a lymphoma model, showing increased dendritic cell maturation and T cell mediated immune response. Further studies including dosing schedule, combination therapy with check-point inhibitors or other immune based treatments will move this technology closer to clinical practice. Disclosures Gordon: Zylem Biosciences: Patents & Royalties: Patents, No Royalties.

Background: Chromosome 9p24.1/PD-L1/PD-L2 genomic copy number alterations (CNAs) including amplifications and copy number gains (CNGs) are predominant features of classic Hodgkin lymphoma (cHL) and lead to overexpression of the programmed death-1 (PD-1) ligands 1 and 2 (PD-L1 and PD-L2). Amplifications and high level CNGs have been associated with advanced stage cHL and inferior treatment outcomes with standard chemotherapy. There are few studies that correlate 9p24.1/PD-L1/PD-L2 amplifications or CNGs with response to PD-1 blockade monotherapy in the frontline setting. We conducted a phase 2 clinical trial of sequential pembrolizumab (PEM) x 3 followed by doxorubicin, vinblastine, dacarbazine (AVD) chemotherapy (4-6 cycles) for newly diagnosed cHL. Interim response to single agent PEM was assessed by PET-CT and by decline in metabolic tumor volume (MTV). Herein, we report the results of correlative studies analyzing 9p24.1 CNAs, PD-1 pathway expression and response to PD-1 blockade. Methods: Pre-treatment diagnostic biopsy specimens were double stained for PD-L1 (E1L3N, XP Cell Signaling) and PAX5, single stained for PD-L2 and pSTAT3, and scored by two expert hematopathologists (QC, LBS) for percentage positive cells and intensity of staining. A modified H score was calculated as the product of staining intensity (0-3) and percentage of positive tumor cells (0-100%), ranging from 0 - 300. Fluorescence in situ hybridization to assess (FISH) chromosome 9p24.1 CNAs was performed by co-hybridizing PD-L1/PD-L2 probes (target) with the centromeric 9 probe (control). In each case, the percentage and magnitude of 9p24.1 CNAs were evaluated. Four FISH categories were defined based on the target: control ratio and the total copy numbers (CNs) of the target per Hodgkin Reed-Sternberg (HRS) cell to include: amplification (ratio≥3, CNs≥ 6), copy number gain (CNGs) (1≤ratio Results: Thirty patients were enrolled from September 2017, through August 1, 2019; 28 had tissue available for FISH analysis and 29 for immunohistochemistry. Response to single agent PEM was PR in 11 (36.7%), near-CMR in 8 (26.7%), and CMR in 11 (36.7%). CMR rate following AVD x 2 was 100%. All patients in this analysis had genomic alterations, although 5 patients did not reach the cut off of 10%. The highest level alteration was amplification in 11 patients (36.7%), copy gain in 7 (23.3%), polysomy in 5 (16.7%) and disomy in 5 (16.7%) (Table 1). The average 9p24.1 copy number per HRS cell was 3.1 (range 2-8.1). Six of 22 examined cases were EBER-positive. There was no evidence of a statistical relationship between response to single agent PEM and 9p24.1 alteration, PD-L1, PD-L2 or STAT3 H-scores, or EBER status. We found PD-L1 H Score tercile differed statistically by FISH category (P=.024, Fisher's Exact Test). Notably, there were no patients with amplification in the lowest tercile. More compelling, we found a positive association between PD-L1 H Score and average 9p24.1 locus copy number (Spearman's ρ=.36, P=.063, Fig 1a) and a negative association between PD-L1 H Score and percent disomic cells (Spearman's ρ= -0.21, P=0.29, Fig 1b) although the statistical significance of these results was limited by the small sample size. Conclusions: Our data is consistent with prior reports indicating a positive association between 9p24.1 genetic alterations and PD-L1 expression. The high response rates observed at all PD ligand levels seen in this clinical study suggests that even low levels of PD ligand expression may be sufficient for response to PD-1 blockade in previously untreated cHL. Disclosures Allen: Bayer:Consultancy, Other;Imbrium:Consultancy, Other;Research to Practice:Speakers Bureau;Clinical Care Options:Speakers Bureau;Curio Sciences:Honoraria.Evens:Merck:Consultancy, Honoraria, Research Funding;Pharmacyclics:Consultancy, Honoraria;Novartis:Consultancy, Honoraria;MorphoSys:Consultancy, Honoraria;Research To Practice:Honoraria, Speakers Bureau;Abbvie:Consultancy, Honoraria;Mylteni:Consultancy, Honoraria;Seattle Genetics:Consultancy, Honoraria, Research Funding;Epizyme:Consultancy, Honoraria, Research Funding.Advani:Celgene, Forty Seven, Inc., Genentech/Roche, Janssen Pharmaceutical, Kura, Merck, Millenium, Pharmacyclics, Regeneron, Seattle Genetics:Research Funding;Astra Zeneca, Bayer Healthcare Pharmaceuticals, Cell Medica, Celgene, Genentech/Roche, Gilead, KitePharma, Kyowa, Portola Pharmaceuticals, Sanofi, Seattle Genetics, Takeda:Consultancy.Pro:Verastem Oncology:Research Funding.Karmali:Takeda:Research Funding;BeiGene:Speakers Bureau;BMS/Celgene/Juno:Honoraria, Other, Research Funding, Speakers Bureau;Karyopharm:Honoraria;AstraZeneca:Speakers Bureau;Gilead/Kite:Honoraria, Other, Research Funding, Speakers Bureau.Gordon:Zylem Biosciences:Patents & Royalties: Patents, No Royalties.Winter:Amgen:Consultancy;Epizyme:Other: DSMB;Norvartis:Consultancy, Other: DSMB;CVS/Caremark:Consultancy;Ariad/Takeda:Consultancy;Delta Fly Pharma:Consultancy;Merck:Membership on an entity's Board of Directors or advisory committees, Other: advisory board;Karyopharm:Membership on an entity's Board of Directors or advisory committees, Other: advisory board.

BACKGROUND: Ibrutinib is a BTK inhibitor approved for relapsed/refractory MCL. We evaluated the safety and efficacy of single-agent ibrutinib maintenance (I-M) following frontline chemo-immunotherapy for MCL in a multicenter phase II trial. Herein, we report preliminary results. METHODS: Patients (Pts) received I-M 560 mg daily for up to 4 years after complete/partial response (CR/PR) to frontline chemo-immunotherapy (+/- autoSCT). The 3-year PFS rate was the primary endpoint. Secondary endpoints were PR to CR conversions, median OS and toxicity. After identifying a trackable clone using archived tissue obtained at diagnosis, minimal residual disease (MRD) was measured using NGS (detection resolution of 1 cell per million; clonoSEQ®; Adaptive Biotechnologies) on peripheral blood at 4 time-points: baseline (after induction but prior to starting I-M) and then at 1, 6 and 18-24 mo(s) after initiation of I-M. RESULTS: 36 pts were enrolled between 7/2014-7/2018. Median age was 60 years (range 46-90). For induction, 17 (47%) received BR, 18 (50%) a cytarabine-containing regimen and 1 (3%) R-CHOP. Eighteen (50%) had autoSCT in CR1. Post-induction +/- autoSCT, 33 (92%) had a CR and 3 (8%) had a PR as best response respectively. One patient converted from PR to CR on I-M. Median f/u was 34.6 months. 5 (14%) pts completed the 4-year I-M course and 15 (42%) remain on I-M (median 31 cycles, range 2-52). Sixteen (44%) pts discontinued I-M early due to: treatment related adverse events (TRAEs; n=12), second malignancies considered unrelated to I-M (n=2), PD (n=1) and death of unknown cause (n=1). Three pts died, 2 deaths deemed unrelated to I-M (aspiration pneumonia, 2nd malignancy) and 1 from unknown cause; 1 pt was lost to follow-up. The most common grade ≥ 3 TRAEs during I-M were neutropenia, HTN, infection, bleeding and atrial fibrillation/flutter (Table 1). TRAEs led to permanent dose reductions in 9 (25%) pts, most commonly for neutropenia (n=3), and I-M discontinuation in 12 (33%), 6 for new onset atrial fibrillation/flutter, 1 each for myalgias, rash, pericardial effusion, mucositis, TIA, subdural hematoma/bleed. Notably, I-M was discontinued in the majority of pts with new onset atrial fibrillation/flutter though not typical of current practice. At the time of data cut-off, MRD was assessed in 21 of 36 pts at varying time points (Figure 1) with remaining samples not yet collected/analyzed. After induction but prior to I-M, 16 pts were confirmed MRD (-), 4 were MRD indeterminate and 1 was MRD (+). Four pts MRD (-) prior to I-M became MRD (+) with follow-up, 2 induced with hyperCVAD, 1 with BR and 1 with R-CHOP + autoSCT prior to I-M; 2 of these pts reverted back to MRD (-) status with ongoing I-M. Of the 2 pts with persistent MRD (+) disease, 1 had clinical progression and the other maintains radiographic CR. Post induction, all MRD indeterminate pts were MRD (-) when checked after 1 month on I-M. The pt who was MRD (+) after front-line treatment (Nordic regimen + autoSCT) remains MRD (+) after 30 cycles of I-M without clinical relapse. MRD correlations with PFS and OS have not yet been performed. CONCLUSION: I-M 560 mg daily is feasible in pts with MCL after response to frontline chemo-immunotherapy. Grade ≥ 3 rates of atrial fibrillation/flutter are consistent with ibrutinib's known safety profile. NGS-based assessments demonstrate that most pts are MRD negative after intensive induction. Longer follow-up and correlation of MRD with PFS and OS are needed to determine the clinical relevance of I-M and MRD status. Disclosures Karmali: BeiGene: Speakers Bureau; AstraZeneca: Speakers Bureau; Karyopharm: Honoraria; Takeda: Research Funding; BMS/Celgene/Juno: Honoraria, Other, Research Funding, Speakers Bureau; Gilead/Kite: Honoraria, Other, Research Funding, Speakers Bureau. Stephens:Arqule: Research Funding; Innate: Consultancy; Juno: Research Funding; Acerta: Research Funding; MingSight: Research Funding; Janssen: Consultancy; Karyopharm: Consultancy, Research Funding; Beigene: Consultancy; Pharmacyclics: Consultancy; Gilead: Research Funding; Verastem: Research Funding. Winter:Norvartis: Consultancy, Other: DSMB; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: advisory board; Epizyme: Other: DSMB; Delta Fly Pharma: Consultancy; Amgen: Consultancy; CVS/Caremark: Consultancy; Ariad/Takeda: Consultancy; Merck: Membership on an entity's Board of Directors or advisory committees, Other: advisory board. Ma:Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; BeiGene: Honoraria, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Research Funding; Bioverativ: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; Juno: Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Kite: Consultancy, Honoraria; TG Therapeutics: Research Funding. Petrich:AbbVie: Current equity holder in publicly-traded company; Daiichi-Sankyo: Current Employment. Hochberg:Intervention Insights: Consultancy; Leuko: Consultancy. Kuhr:Adaptive Biotechnologies: Current Employment. Gordon:Zylem Biosciences: Patents & Royalties: Patents, No Royalties. Pro:Verastem Oncology: Research Funding. OffLabel Disclosure: maintenance ibrutinib after frontline therapy in MCL

BACKGROUND: The human c-MYC oncogene is rearranged or overexpressed in approximately 12% or 37% of aggressive B-cell non-Hodgkin lymphomas (NHL), respectively. Relapses within 18-24 months are observed in more than 50% of these patients when treated with standard chemoimmunotherapy. Ixazomib is an orally bioavailable proteasome inhibitor that is FDA approved for multiple myeloma and has been shown to down-regulate MYC in lymphoma models (Ravi et al., 2016). It has also demonstrated preclinical activity in aggressive NHL, including double-hit (DH) lymphoma. Herein, we report results of a multicenter phase I/II study evaluating the safety and efficacy of induction chemotherapy with DA-EPOCH-R in combination with ixazomib followed by ixazomib maintenance in aggressive MYC-aberrant NHL. METHODS: Adult patients with aggressive MYC-aberrant NHL defined as MYC-overexpression (> 40%) by IHC, MYC-amplification (>4 copies) by FISH, and/or MYC-rearrangement by FISH were eligible. Ixazomib was administered in conjunction with 6 cycles of DA-EPOCH-R. Intrathecal methotrexate prophylaxis was administered using institutional guidelines. Ixazomib was continued as maintenance for up to one year in responders. During phase I, an accelerated titration design was employed to determine the MTD of ixazomib (doses of 2.3 mg, 3 mg or 4 mg) in combination with DA-EPOCH-R. During induction, ixazomib was administered twice per cycle (1 cycle = 21 day), day 1 and day 8 or 15 based on blood counts. For maintenance, ixazomib was dosed at 4 mg weekly. Based on phase I results, 3mg of ixazomib was chosen as the RP2D for phase II. The primary objective was to determine MTD in phase I and to evaluate the efficacy of ixazomib given with DA-EPOCH-R as measured by 12-month PFS rate in phase II. Secondary objectives were to evaluate safety and assess ORR post-induction and OS in all phase I/II patients. RESULTS: Thirty-eight patients were enrolled between 10/2015 and 9/2019 and 36 were evaluable for response. Median age was 63 years (range 31-77) and 27 were male (71%), 86% had advanced stage, 46% had DH or triple hit lymphoma (28% and 18%, respectively), and 89% had an IPI of 2 or higher (Table 1). Twenty-nine (76.3%) patients completed all 6 cycles of induction therapy with DA-EPOCH-R and 25 (65.8%) patients were able to undergo dose escalation of DA-EPOCH-R. Two (5.3%) patients had ixazomib dose reductions during induction and 10 (26.3%) patients had discontinuation of ixazomib during induction. Reasons for early discontinuation during induction included peripheral neuropathy, concomitant comorbidities, progressive disease, and death. Of the 21 (55.3%) patients who received maintenance therapy, 5 (23.8%) had ixazomib dose reductions, and 9 (42.9%) had discontinuation of ixazomib during maintenance. Reasons for early discontinuation during maintenance included peripheral neuropathy, patient preference, and progressive disease. Treatment-related adverse events (TRAEs) of interest occurring in b % 10 % of patients are noted in Table 2. The ORR after induction was 89% with an associated CR rate was 61%. One patient received autologous transplant as consolidation and did not pursue maintenance as a result. Estimated 24-months PFS and OS were 66.9% (95% CI, 50.7% to 88.4%) and 78.7% (95% CI, 65.10% to 95.52%), respectively. Of the 21 patients who received maintenance, sixteen had a CR while 5 had a PR. In those who achieved a PR and went on to receive maintenance, 1 patient converted to CR and 1 maintained a PR with ongoing response at last follow-up. Two patients progressed and 1 has not yet been re-evaluated for response. At a median follow up of 17.6 months (range: 14-19 months), 7 patients had PD. Six patients died, 3 from PD, 1 from respiratory failure, 1 from sepsis, and 1 from natural causes considered unrelated to study drug. CONCLUSION: In this older population with aggressive MYC-aberrant NHL, DA-EPOCH-R induction with adjunctive ixazomib followed by maintenance ixazomib appears to be safe and effective. It is notable that 31% of patients had ixazomib dose reduction or discontinuation during induction and only 55% of patients initiated maintenance, which may have compromised the efficacy of this approach. Exploratory analysis of clinical and histological variables is ongoing and will be presented at the meeting. Improving frontline outcomes for this subset of patients remains a critical unmet need. Disclosures Karmali: Karyopharm: Honoraria; AstraZeneca: Speakers Bureau; BeiGene: Speakers Bureau; Takeda: Research Funding; Gilead/Kite: Honoraria, Other, Research Funding, Speakers Bureau; BMS/Celgene/Juno: Honoraria, Other, Research Funding, Speakers Bureau. Hamadani:Takeda Pharmaceutical Company; Spectrum Pharmaceuticals; Astellas Pharma: Research Funding; ADC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme, AstraZeneca: Speakers Bureau; Janssen R&D; Incyte Corporation; ADC Therapeutics; Celgene Corporation; Pharmacyclics, Omeros, AbGenomics, Verastem, TeneoBio: Consultancy. Gordon:Zylem Biosciences: Patents & Royalties: Patents, No Royalties. Winter:Norvartis: Consultancy, Other: DSMB; Ariad/Takeda: Consultancy; CVS/Caremark: Consultancy; Delta Fly Pharma: Consultancy; Amgen: Consultancy; Epizyme: Other: DSMB; Merck: Membership on an entity's Board of Directors or advisory committees, Other: advisory board; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: advisory board. Ma:TG Therapeutics: Research Funding; Novartis: Research Funding; Juno: Research Funding; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; Kite: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Gilead: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; Bioverativ: Consultancy, Honoraria; BeiGene: Honoraria, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Research Funding. Fenske:Medical College of Wisconsin: Current Employment. Shah:Cell Vault: Research Funding; Miltenyi Biotec: Honoraria, Research Funding; Celgene: Consultancy, Honoraria; Incyte: Consultancy; TG Therapeutics: Consultancy; Verastim: Consultancy; Lily: Consultancy, Honoraria; Kite Pharma: Consultancy, Honoraria. Jagadeesh:Verastem: Membership on an entity's Board of Directors or advisory committees; Debiopharm Group: Research Funding; MEI Pharma: Research Funding; Regeneron: Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding. Klein:Takeda: Membership on an entity's Board of Directors or advisory committees. Petrich:AbbVie: Current equity holder in publicly-traded company; Daiichi-Sankyo: Current Employment. Evens:Epizyme: Consultancy, Honoraria, Research Funding; Merck: Consultancy, Honoraria, Research Funding; Pharmacyclics: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; MorphoSys: Consultancy, Honoraria; Research To Practice: Honoraria, Speakers Bureau; Abbvie: Consultancy, Honoraria; Mylteni: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria, Research Funding. Pro:Verastem Oncology: Research Funding. OffLabel Disclosure: Ixazomib is an orally bioavailable proteasome inhibitor that is FDA approved for multiple myeloma. It has also demonstrated preclinical activity in aggressive NHL, including double-hit (DH) lymphoma.

In this issue of Blood , LaCasce et al present data on the incorporation of brentuximab vedotin (BV) with bendamustine (BVB) in patients with recurrent/refractory classical Hodgkin lymphoma (HL) that might be practice-changing. 1

Autologous stem cell transplantation (ASCT) remains the standard of care for patients with relapsed/refractory (RR) classical Hodgkin lymphoma (cHL) who respond to salvage chemotherapy. However, relapse after ASCT remains a frequent cause of treatment failure, with poor subsequent prognosis. Because cHL is uniquely vulnerable to programmed cell death-1 (PD-1) blockade, PD-1 blockade given as consolidation after ASCT could improve ASCT outcomes. We therefore conducted a multicohort phase 2 study of pembrolizumab in patients with RR cHL after ASCT, hypothesizing that it would improve the progression-free survival (PFS) at 18 months after ASCT (primary end point) from 60% to 80%. Pembrolizumab was administered at 200 mg IV every 3 weeks for up to 8 cycles, starting within 21 days of post-ASCT discharge. Thirty patients were treated on this study. The median age was 33 years, and 90% were high-risk by clinical criteria. Seventy-seven percent completed all 8 cycles. Toxicity was manageable, with 30% of patients experiencing at least 1 grade 3 or higher adverse event (AE), and 40% at least 1 grade 2 or higher immune-related AE. Two patients were lost to follow-up in complete remission at 12 months. The PFS at 18 months for the 28 evaluable patients was 82%, meeting the primary end point. The 18-month overall survival was 100%. In conclusion, pembrolizumab was successfully administered as post-ASCT consolidation in patients with RR cHL, and resulted in a promising PFS in a high-risk patient cohort, supporting the testing of this strategy in a randomized trial. This trial was registered at www.clinicaltrials.gov as #NCT02362997.

Background: MCL carries a poor overall prognosis despite high response rates to induction chemotherapy. Maintenance strategies have impacted survival in MCL but optimal strategies have yet to be defined. Despite profound activity of ibrutinib, a selective BTK inhibitor, in relapsed/refractory MCL, ibrutinib maintenance (I-M) following induction for treatment-naive MCL has not been explored. We report preliminary results of a multicenter phase II trial assessing efficacy and safety of I-M for MCL after frontline induction. Methods: Patients (pts) with MCL with complete or partial response (CR/PR) to frontline chemo-immunotherapy +/- autologous stem cell transplantation (autoSCT) received I-M 560 mg daily for up to 4 years. The primary objective was 3 year PFS rate with I-M. Secondary objectives were PR to CR conversions, median OS after 4 years and toxicity. Measurable residual disease (MRD) assessments using an NGS-MRD Assay (detection resolution of < 1 cell per million; Adaptive Biotechnologies) on peripheral blood and/or PBMCs were planned at 4 time points: prior to I-M initiation and at 1, 6 and 18-24 mo(s) after initiation of I-M. Results: Accrual is complete (n=36). Median age was 60 (range 46-90), 28 pts (78%) were males, 28 (78%) had advanced stage and 9 (25%) had extranodal disease. 18 (50%), 7 (19%) and 11 (31%) had low vs intermediate vs high risk MIPI respectively. For induction, 17 (47%) received bendamustine-rituximab (BR), 18 (50%) a cytarabine-based regimen, and 1 (3%) R-CHOP. 18 (50%) had autoSCT in CR1 prior to enrollment. 33 (92%) and 3 (8%) had CR and PR with induction respectively with 1 PR to CR conversion on I-M. Median follow-up from initiation of induction therapy was 33 mos. With a median follow-up of 24.5 mos from initiation of I-M, 1 pt had disease progression (PD) and 2 others died, 1 from hepatic cholangiocarcinoma 2 years after I-M discontinuation for toxicity (atrial fibrillation) and 1 from unknown cause. 20/36 (56%) pts remain on I-M (median 24 cycles, range 1-52). Sixteen pts discontinued ibrutinib, including 3 for completion of 4 years of I-M. Of the remaining 13 who discontinued, TRAEs accounted for 10 (77%) and the other 3 were for uterine cancer (n=1), PD (n=1), and death of unknown cause (n=1) (Table 1). Atrial fibrillation/atrial flutter accounted for 50% (n=5) of TRAEs that led to I-M discontinuation. 9 (25%) pts required permanent dose reductions for TRAEs with neutropenia (n=3), myalgias (n=2), and fatigue (n=2) being the most common. Collectively, TRAEs led to dose reductions/ interruptions/ discontinuations in 25 (69%) pts. At time of data cut-off, (July 2019), using a trackable dominant clone identified from tissue at diagnosis, MRD was assessed in 12 patients at varying time points (Figure 1). In these 12 pts, 6 were induced with BR, 5 with a cytarabine-based regimen, and 1 with R-CHOP and 5 were consolidated with autoSCT prior to enrollment. Prior to I-M initiation, 9 pts were MRD (-) and 3 had indeterminate MRD status. Indeterminate results corresponded with total cell counts below the level of detection and quantification with our assay. Those with indeterminate MRD status were confirmed to be MRD (-) with subsequent evaluation after 1 month of I-M. 3 of 12 (25%) pts became MRD (+) on I-M. The first reverted back to MRD (-) status and remains MRD (-) with clinical CR on > 3 years of I-M. The second pt was treated with hyperCVAD with PR prior to I-M. This patient required several dose interruptions for neutropenia just prior to MRD detection with clinical PD leading to discontinuation of therapy after 9 months of I-M. The third pt was treated with R-CHOP + autoSCT with PR prior to I-M and maintains a PR despite MRD conversion on > 2 years of I-M. Further analysis of dynamic changes in dominant and non-dominant clones associated with I-M is ongoing. Conclusions: I-M is feasible in MCL pts who respond to frontline chemo-immunotherapy +/- autoSCT with manageable toxicities consistent with the known safety profile of ibrutinib. Guidelines to discontinue I-M for atrial fibrillation were strictly upheld in this protocol though not typical of current practice. NGS can be used to assess MRD with induction and maintenance therapy and demonstrates that most pts are MRD negative after intensive induction. Longer follow-up, evaluation of dynamic changes in MRD, and PFS and OS data are needed to assess clinical relevance of I-M and importance of MRD status, and may support larger, controlled studies. Disclosures Karmali: Gilead/Kite; Juno/Celgene: Consultancy, Speakers Bureau; Takeda, BMS: Other: Research Funding to Institution; Astrazeneca: Speakers Bureau. Abramson:AbbVie Inc, Amgen Inc, Bayer HealthCare Pharmaceuticals, Celgene Corporation, EMD Serono Inc, Genentech, Gilead Sciences Inc, Janssen Biotech Inc, Juno Therapeutics, a Celgene Company, Karyopharm Therapeutics, Kite Pharma Inc, Merck, Novartis, Seattle Gen: Consultancy. Stephens:Karyopharm: Research Funding; Gilead: Research Funding; Acerta: Research Funding. Winter:Merck: Consultancy, Research Funding. Ma:Genentech: Consultancy; Gilead: Research Funding; Astra Zeneca: Consultancy, Research Funding, Speakers Bureau; Acerta: Research Funding; Abbvie: Research Funding; Incyte: Research Funding; Janssen: Consultancy, Speakers Bureau; Kite: Consultancy; Juno: Research Funding; Xeme: Research Funding; Pharmacyclics: Consultancy, Research Funding, Speakers Bureau; Beigene: Research Funding; Bioverativ: Consultancy; Novartis: Research Funding. Petrich:Abbvie: Employment, Equity Ownership. Kuhr:Adaptive Biotechnologies: Employment, Other: shareholder. Gordon:Zylem LLC: Other: co-founder; research in nanoparticles in cancer; Bayer: Other: Advisory Board; Juno/Celgene: Other: Advisory Board, Research Funding; Gilead: Other: Advisory Board. Pro:Takeda: Consultancy, Honoraria, Other: Travel Expenses; Celgene: Consultancy, Honoraria; Kyowa Hakka Kirin: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria, Other: Travel Expenses, Research Funding. OffLabel Disclosure: We will discuss results of our trial looking at ibrutinib maintenance in frontline MCL

Introduction: Hematologic malignancies, including B cell lymphomas such as diffuse large B cell lymphoma (DLBCL) and follicular lymphoma (FL), have increased demands for cholesterol and cholesteryl esters to maintain membrane anchored pro-proliferative and pro-survival signaling pathways, including B cell receptor signaling. Recent evidence suggests that certain cancer cell lines, including several anaplastic large T cell lymphoma (ALCL) cell lines, are auxotrophic for cholesterol and are sensitive to cholesterol reduction-induced ferroptosis (Garcia-Bermudez, Nature 2019), an iron dependent form of programmed cell death characterized by accumulation of lipid peroxides. We have developed a cholesterol depleting functional lipoprotein-like nanoparticle (Flip-NP) that specifically targets the high-affinity HDL receptor, scavenger receptor type B1 (SCARB1), which maintains cellular and cell membrane cholesterol homeostasis. Our prior data demonstrated that Flip-NPs induce B cell lymphoma cell death in vitro and in in vivo xenograft models. Accordingly, we hypothesized that the mechanism of cell death by Flip-NPs in B cell lymphomas is ferroptosis, and that Flip-NPs would be potent therapy for an expanded number of cholesterol-addicted malignancies, including ALCL. Methods: After informed consent, primary B cell lymphoma cells were isolated from excisional biopsies from patients with FL or DLBCL. The SUDHL4 [germinal center (GC) DLBCL], Ramos [Burkitt's lymphoma], SUDHL1 [ALCL] and SR-786 [ALCL] cell lines were used for in vitro experiments. SCARB1 expression was quantified using flow cytometry and western blot analysis. Cell viability was quantified using the MTS assay and flow cytometry. Ferroptosis was measured using the lipophilic antioxidant ferrostatin-1 or the iron chelator deferoxamine. Gene expression changes were quantified using RT-qPCR. Lipid peroxidation was measured using C11-BODIPY and flow cytometry. SUDHL1 and SUDHL4 flank tumor xenografts were initiated in SCID-beige mice, with Flip-NPs administered 3 times per week IV. Results: Primary B cell lymphoma cells were isolated from patients with FL (n=4) or DLBCL (n=2), and all samples expressed some level of SCARB1 by flow cytometry. Flip-NPs increased cell death in 3 of the 4 FL samples and 1 of 2 DLBCL samples. In Ramos and SUDHL4 cells, RT-qPCR data showed that Flip-NP-mediated cholesterol reduction led to up-regulation of cholesterol biosynthesis genes and down-regulation of glutathione peroxidase-4 (GPX4), a critical protein responsible for degradation of lipid peroxides. Correspondingly, as shown with C11-BODIPY, Flip-NP treatment increased lipid peroxide accumulation in Ramos and SUDHL4 cells. Addition of ferrostatin-1 or deferoxamine reduced Flip-NP induced cell death, demonstrating that the mechanism-of-action of Flip-NPs involves, at least in part, ferroptosis. Given the sensitivity of cholesterol auxotrophic cell lines to cholesterol reduction-induced ferroptosis, we tested the efficacy of the Flip-NPs against cholesterol auxotrophic ALK+ ALCL cell lines SUDHL1 and SR-786. SCARB1 was expressed in both cell lines. Flip-NPs potently induced cell death in both SUDHL1 and SR-786 cells in vitro. In vivo, systemic administration of Flip-NPs reduced tumor volumes in both SUDHL4 and SUDHL1 tumor xenograft models. Conclusions: Our data show that Flip-NPs reduce GPX4 expression and increase lipid peroxide accumulation in B cell lymphoma cell lines, resulting in ferroptosis. Expanding on these results, Flip-NP efficacy was also demonstrated in cholesterol auxotrophic ALK+ ALCL cell lines and primary patient-derived B cell lymphoma cells. These in vitro results translated to in vivo murine models, as systemic administration of Flip-NPs potently reduced DLBCL and ALK+ ALCL tumor xenograft burden. Flip-NPs are a molecularly targeted, first-in-class therapy that may be effective for malignancies reliant upon cellular cholesterol. Disclosures Behdad: Pfizer: Other: Speaker; Thermo Fisher: Membership on an entity's Board of Directors or advisory committees; Loxo-Bayer: Membership on an entity's Board of Directors or advisory committees. Karmali:Astrazeneca: Speakers Bureau; Takeda, BMS: Other: Research Funding to Institution; Gilead/Kite; Juno/Celgene: Consultancy, Speakers Bureau. Thaxton:Zylem: Other: Co-founder of the biotech company Zylem. Gordon:Juno/Celgene: Other: Advisory Board, Research Funding; Gilead: Other: Advisory Board; Bayer: Other: Advisory Board; Zylem LLC: Other: co-founder; research in nanoparticles in cancer.

Background: Pembrolizumab (PEM), an anti-PD-1 antibody is approved for the treatment of relapsed/refractory cHL based on results of a pivotal trial demonstrating an overall response rate (ORR) of 69% and 22% complete response (CR) rate. To investigate the impact of PEM monotherapy in previously untreated patients (pts), we conducted a phase 2 clinical trial of sequential PEM followed by AVD chemotherapy for untreated cHL. Herein, we report the primary analysis of response (PET2) to single agent PEM in the frontline setting and the results of interim FDG18-FDG PET-CT (PET3) following AVD x 2. Methods: Pts > 18 years of age with newly diagnosed cHL stages I-IV, including early stage pts with at least 1 risk factor according to NCCN criteria, were eligible. Pts were treated sequentially with 3 cycles of PEM at 200 mg every 3 weeks followed by an interim PET-CT (PET2) for primary analysis. Subsequently, pts received 4-6 cycles of AVD chemotherapy based on initial stage, with PET-CT's repeated after 2 cycles of AVD and at the end of therapy. There was no consolidative radiotherapy. Response to single agent PEM was assessed by Lugano criteria and decline in total metabolic tumor volume (TMV). We hypothesized that PEM monotherapy prior to AVD would result in a CR rate of 50% and would reduce the frequency of PET-positivity on the interim PET (PET3) following 2 cycles of AVD compared to prior reports. Results: Thirty pts enrolled from September 2017- March 2019 with a data cutoff of June 14, 2019. The median age of participants was 30 (range, 21-77), and 4 pts were ages >60. Eleven were male, and the majority (83%) were Caucasian. Twelve pts had early unfavorable disease (6 each with elevated ESR, B-symptoms, and bulky mediastinal masses). Eighteen pts had advanced stage disease (5 Stage 3, 13 Stage 4; IPS score 3 -4 in 7, 1-2 in 10). Adverse risk factors for all 30 pts included bulky disease or large mediastinal mass (n=12), B-symptoms (n=14) and extranodal disease (n=16). Overall therapy was well tolerated and most adverse events were grade 1-2. Related events of any grade included hypertension (n=10), rash (n=9), anemia (n=8), infusion reactions (n=5), elevated liver function tests (n=5), arthralgias (n=4) and hypo- or hyperthyroidism (n=3). Grade 3 and 4 events (whether or not judged to be related) were as follows Gr3: lymphopenia (n=4), febrile neutropenia (n=3), neutropenia (n=3), hypertension (n=2), diarrhea (n=1), hyperglycemia (n=1), and hyponatremia (n=1); Gr 4: neutropenia (n=10); transaminitis (n=1); sepsis (n=1). The only Grade 3 or 4 immune-related adverse event was the one grade 4 transaminitis that resolved with steroid administration and a delay in therapy. Eleven of 30 pts achieved CR (37%; Deauville 1-3) following initial PEM monotherapy including three with large mediastinal masses. Four additional patients with bulky disease and four others had major reductions in disease following PEM monotherapy, but did not achieve CR by Lugano criteria (Fig 1A). To better characterize the depth of response, we quantitated the decline in total metabolic tumor volume (TMV) (Fig 1B). Eight of the 17 pts with < CR to PEM monotherapy for whom TMV could be analyzed had > 90% reduction in TMV. A single pt had an atypical response with clearance of original disease sites, but development of new sites that resolved after two cycles of AVD. Across all pts, the CR (Deauville 1-3) rate following 2 cycles of AVD, was 100%. Median follow up is 6.5 (range: 1 - 12) months among those who have completed therapy. No pt has required a change in treatment, relapsed, or progressed, with progression-free and overall survival rates both at 100%. Conclusion: Although the study did not meet its primary endpoint, our data demonstrate that 3 cycles of PEM is highly active in pts with newly diagnosed early unfavorable or advanced stage cHL. PEM monotherapy resulted in > 90% reduction in TMV in the majority of pts, and when followed by AVD x's 2, CR in 100%. No pts have experienced progression or change of therapy to date and treatment was overall very well tolerated. This radiotherapy- and bleomycin-free approach warrants further investigation in larger trials to confirm response rates and assess efficacy compared with other novel combinations in the frontline setting. Disclosures Pro: Takeda: Consultancy, Honoraria, Other: Travel Expenses; Celgene: Consultancy, Honoraria; Kyowa Hakka Kirin: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria, Other: Travel Expenses, Research Funding. Karmali:Gilead/Kite; Juno/Celgene: Consultancy, Speakers Bureau; Takeda, BMS: Other: Research Funding to Institution; Astrazeneca: Speakers Bureau. Gordon:Gilead: Other: Advisory Board; Juno/Celgene: Other: Advisory Board, Research Funding; Zylem LLC: Other: co-founder; research in nanoparticles in cancer; Bayer: Other: Advisory Board. Winter:Merck: Consultancy, Research Funding.

Background: Immunocompromised patients (pts) face an approximate 6-fold increase in lifetime risk of lymphoid malignancies compared with immunocompetent counterparts. Additionally, up to 80% of post-transplant lymphoproliferative disease (PTLD) cases are driven by EBV-associated mechanisms of tumorigenesis. Approximately 70% will express CD30 and over 80% will express CD20. Recent studies of chemoimmunotherapy (CIT) have reported median overall survival (OS) of 2-4 years and treatment-related mortality (TRM) rates of 13-50%. Moreover, solid organ transplant (SOT) pts are at significant risk of graft rejection when CIT is employed, possibly due to "off target" depletion of regulatory T-cell populations. R monotherapy induction, followed by response-stratified use of CIT, has been evaluated (Trappe, et al, JCO, 2016). However, ~75% of pts had an inadequate response to R alone and required subsequent CIT; 2-yr OS for the population as a whole was ~70%. BV is an anti-CD30 antibody-drug conjugate that received accelerated FDA approval for previously untreated CD30+ T-cell lymphoma and Hodgkin lymphoma. We hypothesized that a combination of BV and R would yield improved breadth and depth of response compared with R monotherapy induction, would spare pts subsequent exposure to CIT, and result in favorable OS. Methods: We report here results of a phase I/II multicenter study investigating the efficacy and safety of BV+R as frontline therapy in pts diagnosed with immunosuppression-associated CD30+ and/or EBV+ lymphoid malignancies. Induction consisted of R 375 mg/m2 given days 1, 8, 15, 22 and BV 1.2 mg/kg given days 1, 8, 15, of a 28-day cycle, followed by restaging. Those with progression were removed from study. Pts with stable disease were offered study discontinuation or completion of one consolidation cycle followed by repeat disease assessment. Pts with partial response or complete response (CR) could receive either consolidation followed by maintenance therapy (MT) or move directly to MT without consolidation. Consolidation was identical to induction dosing; MT consisted of BV 1.8 mg/kg every 3 weeks and R 375 mg/m2 every 6 weeks for up to 1 year of therapy. Toxicity was defined using CTCAE 4.0 and response (Cheson, 2007) was assessed at the end of induction, consolidation (if given), and after cycles 4 and 7 of BV. Results: A total of 22 pts were entered in the trial. Toxicity and response data are available for 20 pts. Median age was 67 years (range, 30-79) and 14 pts (64%) were male (range, 30-79 years). Fourteen pts (64%) had received either a SOT or hematopoietic allograft requiring immunosuppression, 3 pts required immunosuppression for underlying rheumatologic conditions, and 3 pts were found to have EBV-associated lymphoid malignancies in the absence of iatrogenic immunosuppression (Table 1). Overall response rate was 70%, including a CR rate of 60%. With median follow-up of 26.1 month, the probability of progression-free survival at 1 year was 75.2% and 67.6% at 3 years (Fig 1). Probability of OS was 89.2% at both 1-year and 3-year follow-up (Fig 1). Median time to best response was 28 days. Three pts withdrew consent after induction, 2 pts died (1 death related to treatment), and 1 patient was lost to follow-up. Seven pts (31%) required dose adjustments or delay of medication administration during induction therapy and 45% required discontinuation of therapy due to toxicity within 1 year. The most frequent grade 3/4 toxicities were peripheral neuropathy, neutropenia, lymphopenia, and pancreatitis. The most frequent adverse events of any grade were fatigue, nausea, abdominal pain, pancytopenia, and peripheral neuropathy (Table 2). Conclusions: The combination of BV + R had an acceptable safety profile and appeared effective in achieving early remissions when used as frontline therapy for PTLD and other immunosuppression-related lymphomas. Specifically, over half of pts achieved CR, and 75% have been spared exposure to multi-agent cytotoxic chemotherapy. Furthermore, survival and PFS data were encouraging compared with historical controls. However, nearly half of pts discontinued therapy within 1 year due to toxicity suggesting poor long-term tolerance of the regimen and that earlier cessation of therapy may be warranted. Further studies are needed to confirm these efficacy results and to determine optimal BV+R dosing regimens and durations. Disclosures Pro: Seattle Genetics: Consultancy, Honoraria, Other: Travel Expenses, Research Funding; Takeda: Consultancy, Honoraria, Other: Travel Expenses; Celgene: Consultancy, Honoraria; Kyowa Hakka Kirin: Consultancy, Honoraria. Gordon:Gilead: Other: Advisory Board; Bayer: Other: Advisory Board; Juno/Celgene: Other: Advisory Board, Research Funding; Zylem LLC: Other: co-founder; research in nanoparticles in cancer. Karmali:Gilead/Kite; Juno/Celgene: Consultancy, Speakers Bureau; Astrazeneca: Speakers Bureau; Takeda, BMS: Other: Research Funding to Institution. Winter:Merck: Consultancy, Research Funding. Ma:Astra Zeneca: Consultancy, Research Funding, Speakers Bureau; Xeme: Research Funding; Bioverativ: Consultancy; Beigene: Research Funding; Pharmacyclics: Consultancy, Research Funding, Speakers Bureau; Kite: Consultancy; Janssen: Consultancy, Speakers Bureau; Genentech: Consultancy; Abbvie: Research Funding; Incyte: Research Funding; Juno: Research Funding; Acerta: Research Funding; Gilead: Research Funding; Novartis: Research Funding. Behdad:Pfizer: Other: Speaker; Thermo Fisher: Membership on an entity's Board of Directors or advisory committees; Loxo-Bayer: Membership on an entity's Board of Directors or advisory committees. Petrich:AbbVie: Employment, Equity Ownership. Smith:Portola Pharmaceuticals: Research Funding.

Background: Despite excellent outcomes in the front-line management of classical Hodgkin lymphoma (cHL), patients with relapsed or refractory disease typically undergo second-line cytotoxic chemotherapy before proceeding to consolidation with autologous hematopoietic stem cell transplant (autoHSCT). Pre-transplant F18-FDG-PET imaging is a well-established predictor of outcomes following autoHSCT; a complete metabolic response (CMR) to second-line therapy defined as a Deauville score 1-3 predicts a favorable outcome and is a requirement for transplant at many centers. The PD-1 pathway plays an important role in the pathogenesis of cHL and checkpoint inhibition with agents including PEM and nivolumab have shown efficacy as monotherapy in heavily pretreated disease. We hypothesized that the addition of PEM to ICE (ifosfamide, carboplatin, and etoposide) chemotherapy will increase the rate of CMR by PET-CT prior to autoHSCT without impairing the mobilization of peripheral blood progenitor cells (PBPC) or engraftment. Here we present interim safety and toxicity data from this ongoing trial (NCT03077828) including the yields of PBPC mobilization and engraftment. Methods: Enrollment criteria include patients age >18 years medically fit for autoHSCT with relapsed/refractory cHL and excludes those with prior PD-1 inhibitor exposure, CNS involvement, more than 2 prior regimens or history of autoimmune disease. Patients are treated with 2 cycles of PEM 200 mg IV on day 1 in combination with ICE chemotherapy (ifosfamide 5000 mg/m2 day 2 CIV over 24hr, carboplatin AUC 5 IV day 2, etoposide 100 mg/m2 IV days 1-3) on a Q21 day cycle. PBPC mobilization and harvest are performed per institutional protocol on recovery post-cycle #2. A cycle of PEM 200 mg IV is then administered as monotherapy followed by response assessment with PET-CT. Patients with Deauville scores ≤3 proceed to autoHSCT per institutional protocol. A third cycle of PEM+ICE is optional following the PET-CT assessment. Neither the conditioning regimen nor management during transplantation is dictated by the protocol. Results: As of July 2019, 23 of 40 planned patients have evaluable safety and toxicity data. One patient had inconclusive pathology and was removed from study after one cycle of PEM-ICE but is included for this report. The median age was 32 (range 19-62) and 17 of 23 patients were females (74%). 8 patients were refractory to first-line therapy, and 9 relapsed within one year of treatment. 19 patients had received ABVD. Following protocol directed therapy, all but one patient had successful mobilization and collection; one had a severe allergic reaction to filgrastim and underwent bone marrow harvest instead. 16 patients collected in a single day of apheresis; the remainder collected within 4 days. The median number of stem cells harvested was 12.6 x 106 CD34+ cells/kg (range 4.2 - 46.1 x 106/kg). 3 patients underwent the 3rd cycle of PEM + ICE chemotherapy. 3 patients had Deauville scores >3 on FDG-PET response assessment; two had biopsies showing only benign processes and proceeded to transplant. Following stem cell reinfusion, all patients successfully engrafted, with a median time to absolute neutrophil and platelet recovery of 11 days (range: 9 - 24) and 12 days (range: 9 - 23), respectively. The combination of PEM + ICE chemotherapy was well tolerated. There were no reports of pneumonitis, colitis, hepatitis, or endocrinopathies. The most common toxicities were cytopenias, mucositis, diarrhea and febrile neutropenia. A single death on protocol was deemed secondary to advanced cardiovascular disease discovered mid-treatment during the patient's pre-transplant assessment. There was no clinical evidence to suggest an inflammatory process resulting in the cardiac arrest. Conclusions: The combination of PEM with ICE chemotherapy in relapsed / refractory cHL appears tolerable and safe. We found no significant hindrance to peripheral blood stem cell harvest and PEM- related AEs were uncommon. Additionally, pre-treatment with a checkpoint inhibitor prior to autoHSCT appears safe thus far and does not appear to delay engraftment. Disclosures Casulo: Celgene: Research Funding; Gilead: Honoraria, Other: Travel, accommodation, expenses; Roche: Other: Travel, accommodation, expenses. Karmali:Takeda, BMS: Other: Research Funding to Institution; Gilead/Kite; Juno/Celgene: Consultancy, Speakers Bureau; Astrazeneca: Speakers Bureau. Pro:Celgene: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Other: Travel Expenses; Kyowa Hakka Kirin: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria, Other: Travel Expenses, Research Funding. Mehta:Millennium/Takeda, Celgene; stock in Celgene, Bristol-Myers Squibb and Bluebird: Speakers Bureau. Gordon:Bayer: Other: Advisory Board; Juno/Celgene: Other: Advisory Board, Research Funding; Gilead: Other: Advisory Board; Zylem LLC: Other: co-founder; research in nanoparticles in cancer. Winter:Merck: Consultancy, Research Funding.

Introduction: Aggressive B cell lymphomas are clinically challenging, especially in the relapsed/refractory setting. Synthetic DNAs containing the unmethylated cytosine-phosphate-guanine (CpG) deoxynucleotides motif are potent stimulants of the innate immune system. CpGs bind to toll-like receptor 9 (TLR9) in the endosomes. Activation of TLR9 leads to G1-phase arrest of lymphoma cells and induces apoptosis via the Fas ligand pathway. Class B CpGs are linear single stranded DNA that stimulate B cells, while class C CpGs form a duplex secondary structure and act on both B cells and dendritic cells. Witzig et al. (Am J Hematol 2013) used class B CpGs in combination with radioimmunotherapy for B cell lymphomas and had an overall response rate of 93% with 63% complete responses. More recently, Frank et al. (Cancer Discovery 2018) used class C CpGs in combination with radiation to treat advanced stage indolent lymphoma and found that both treated and untreated sites had significant lymph node shrinkage. However, only 7 of 29 qualified for partial response. We have previously shown that CpG conjugated gold nanoparticles (NPs) improve macrophage stimulation. Therefore, we hypothesize that CpG-conjugated gold NPs can enhance the CpG's anti-lymphoma effects though direct and immune mediated mechanisms (Figure 1A). Material and Methods: Using a previously verified triethylene glycol modified CpG (tmCpG) design, we synthesized class B tmCpG NPs (1826 for mice, 2006 for human) and class C tmCpG NPs (2395). Lymphoma cell lines (SUDHL4, Ramos, A20) and bone marrow derived dendritic cells (JAWSII) were used in in vitro and in vivo assays. Viability was measured by MTS and apoptosis by annexin V-PI flow cytometry. For dual tumor studies, A20 lymphoma cells were injected subcutaneously in both flanks of BALB/c mice. The side with the larger tumor was treated with either PBS, free CpG, or tmCpG NPs intratumorally on days 1, 4, and 8. Tumors were monitored for growth and, when either tumor reached 2 cm3, the mice were euthanized. Results: Changing the CpG sequence did not alter the monolayer formation on the nanoparticles, and 1nM of tmCpG NPs are equivalent to 0.5ug/ml of CpGs. Class C tmCpG NPs (2395) tend to form aggregates during washing and collection phases but could be sonicated back into suspension. Both class B (1826 and 2006) and class C (2395) tmCpG NPs significantly reduced viability of SUDHL4, Ramos, and A20 cells, compared with free CpGs, while having no effect on the viability of JAWSII cells. tmCpG NPs induced lymphoma cell death by apoptosis as measured by annexin V-PI. In in vivo studies, both class B free CpG and class B tmCpG NP groups had reduced tumor growth and improved survival compared with PBS controls. Nine of 15 mice (60%) in the tmCpG NP group had no detectable tumor on the treated side, while only 4 of 15 mice (27%) in the free CpG group had no tumors. On the untreated side, there was no difference in tumor growth between the three groups. In another dual tumor study, the class C tmCpG NPs trended towards a reduction of tumor growth in both the treated and untreated tumors by comparison to free CpG or PBS but the sample size was too small (n=4) to achieve statistical significance. One of the 4 mice in the class C tmCpG NP group had complete resolution of both treated and untreated tumors, while all of the PBS and free CpG mice died before day 28, suggesting that there was an abscopal effect generated by using the nanoparticle construct (Figure 1B). Conclusions: The tmCpG NP design significantly improved cytotoxicity of CpGs toward lymphoma compared with free CpGs. Class B tmCpG NPs had stronger direct cytotoxic effects at the treated tumor site compared with free CpG, while class C tmCpG NPs had immune effects at the distant untreated sites. Future studies should focus on re-engineering the platform to stabilize and optimize tmCpG NPs for improved anti lymphoma activity. Disclosures Karmali: Gilead/Kite; Juno/Celgene: Consultancy, Speakers Bureau; Takeda, BMS: Other: Research Funding to Institution; Astrazeneca: Speakers Bureau. Thaxton:Zylem: Other: Co-founder of the biotech company Zylem. Gordon:Juno/Celgene: Other: Advisory Board, Research Funding; Gilead: Other: Advisory Board; Zylem LLC: Other: co-founder; research in nanoparticles in cancer; Bayer: Other: Advisory Board.

Background Duvelisib, an oral dual PI3K-δ and PI3K-γ inhibitor, is approved by the US Food and Drug Administration for the treatment of adult patients with relapsed or refractory (R/R) follicular lymphoma (FL) after ≥ 2 prior systemic therapies. In multiple phase 1-3 studies that included patients with iNHL, duvelisib was shown to be efficacious, with a favorable risk-benefit profile. This study will evaluate whether duvelisib efficacy at the approved 25 mg twice daily (BID) dose can be achieved and maintained with an acceptable or improved safety profile by the inclusion of prespecified 2-week drug holidays in patients with R/R iNHL. Study Design and Methods TEMPO is a randomized, open-label, multicenter, international, phase 2 study of duvelisib in adult patients with R/R iNHL in whom ≥ 1 line of prior therapy has failed. The primary objective is to evaluate the efficacy of duvelisib administered with prescribed drug holidays, with the primary endpoint of overall response rate (ORR) by the 2007 revised International Working Group criteria. Key secondary endpoints include ORR by the 2014 Lugano criteria, progression-free survival, overall survival, time to treatment failure, duration of response, lymph node response rate, time to the first response, adverse event profile, and determination of pharmacokinetics parameters. Exploratory objectives include assessment of quality of life and biomarkers of treatment response and toxicity. Key inclusion criteria include histologically confirmed FL grades 1 to 3a, marginal zone lymphoma (splenic, nodal, or extranodal) or small lymphocytic lymphoma, radiological evidence of disease progression and ≥ 1 bidimensionally measurable lesion ≥ 1.5 cm, adequate organ function, and Eastern Cooperative Oncology Group performance status ≤ 2. Key exclusion criteria include prior allogeneic hematopoietic stem cell transplant; previous treatment with a PI3K inhibitor; history of drug-induced colitis or drug-induced pneumonitis; ongoing treatment for systemic infection; central nervous system NHL; prolonged QT interval; history of tuberculosis treatment within the 2 past years; history of stroke, unstable angina, myocardial infarction, or ventricular arrhythmia requiring medication or mechanical control within the past 6 months; history of or concurrent interstitial lung disease of any severity and/or severely impaired lung function; ongoing treatment with chronic immunosuppressants; and any unstable or severe uncontrolled medical condition. A total of 102 patients are planned to be enrolled. Patients will be randomized 1:1 to 2 arms and stratified by number of prior therapies (1 or > 1), bulky disease status (longest diameter of baseline lesion < 5 cm or ≥ 5 cm), and time since last recurrence (≥ 24 months or < 24 months). In arm 1, patients will receive duvelisib 25 mg BID for one 10-week (W) cycle followed by 25 mg BID on W3 and W4 of each subsequent 4-week cycle. In arm 2, patients will receive duvelisib 25 mg BID on W1, W2, W5, W6, W9, and W10 of one 10-week cycle and then on W3 and W4 of each subsequent 4-week cycle. Patients will be treated until disease progression, unacceptable toxicity, or withdrawal. This study will test the null hypothesis that the ORR in each arm is ≤ 30% against the alternative that the ORR is ≥ 55%. The study has a 2-stage design. In stage 1, 15 patients will be enrolled in each arm, with response assessment after ≥ 3 cycles. If there are fewer than 6 partial or complete responses, consideration may be given to terminating the arm. Otherwise, in stage 2, 36 additional patients will be enrolled, for a total of 51 per arm. Enrollment is planned to be initiated in August 2019. Approximately 50 sites will be open for enrollment across the United States, Europe, and Asia. Disclosures Karmali: Takeda, BMS: Other: Research Funding to Institution; Gilead/Kite; Juno/Celgene: Consultancy, Speakers Bureau; Astrazeneca: Speakers Bureau. Youssoufian:Verastem Oncology: Consultancy, Equity Ownership. Sprott:SMOC Therapeutics: Employment, Equity Ownership; Verastem Oncology: Employment, Equity Ownership. Weaver:FemtoDx: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties: Inventor; Verastem Oncology: Employment, Equity Ownership, Patents & Royalties: Inventor; Hillstream Biopharma: Consultancy, Equity Ownership. Narasimhan:Verastem: Employment, Equity Ownership. Lustgarten:Verastem: Employment. Patrick:Verastem Oncology: Employment. Zalutskaya:Verastem Inc: Employment, Equity Ownership. Gordon:Gilead: Other: Advisory Board; Juno/Celgene: Other: Advisory Board, Research Funding; Zylem LLC: Other: co-founder; research in nanoparticles in cancer; Bayer: Other: Advisory Board. OffLabel Disclosure: Duvelisib (DUV), a dual PI3K-delta,gamma inhibitor, is US FDA approved at 25 mg twice daily (BID) for the treatment of R/R chronic lymphocytic leukemia or small lymphocytic lymphoma after at least 2 lines of prior therapy and R/R follicular lymphoma after at least two prior systemic therapies.

Background : CAR T cell therapies have demonstrated high response rates in patients (pts) with R/R B cell NHL. Liso-cel is an investigational anti-CD19, defined composition, 4-1BB CAR T cell product administered at target doses of CD4+ and CD8+ CAR T cells. The seamless phase 1 TRANSCEND NHL 001 study evaluated liso-cel in pts with R/R large B cell NHL (NCT02631044). We present data with long-term follow-up from pts treated in the DLBCL cohort. Methods: Pts aged ≥18 yrs in the DLBCL cohort had R/R DLBCL not otherwise specified (NOS; including transformed from any indolent lymphoma), high-grade B cell lymphoma (HGBCL) with MYC and BCL2 and/or BCL6 rearrangements, primary mediastinal B cell lymphoma (PMBCL), or follicular lymphoma grade 3B (FL3B). Pts had R/R disease after ≥2 lines of therapy and ECOG PS 0‒2. Pts with grade 3/4 cytopenias, mild-moderate organ dysfunction, and secondary CNS lymphoma were eligible. Bridging therapy was allowed, but pts had to have PET-positive disease before lymphodepletion (LD) with fludarabine and cyclophosphamide. Liso-cel was administered at 1 of 3 target dose levels (DLs) of 50×106 (DL1), 100×106 (DL2), or150×106 (DL3) viable CAR+ T cells in the dose-finding cohorts. All dose levels were expanded, and DL2 was chosen as the target DL for dose confirmation. Primary endpoints were treatment-emergent adverse events (TEAEs) and overall response rate (ORR). Secondary endpoints included CR rate, DOR, PFS, PFS ratio, and OS. TEAEs, including investigator-identified neurological events (NE) related to liso-cel, were graded using CTCAE criteria; CRS was graded per the Lee criteria (2014). ORR was assessed by independent review using the Lugano criteria. Data from all liso-cel-treated pts in the DLBCL cohort were analyzed across DLs. Results: A total of 342 pts were leukapheresed; 268 pts received liso-cel (DL1, n=51; DL2, n=176; DL3, n=41). Twenty-four pts received nonconforming product; product could not be manufactured for 2 pts. Pts did not receive liso-cel primarily due to death (n=33). In the optimized manufacturing process, median time from leukapheresis to liso-cel availability was 24 days. Median age was 63 (range, 18‒86) yrs, including older subpopulations (≥65 yrs, 41%; ≥75 yrs, 10%); 65% of pts were male. At screening, 58% had ECOG PS 1. Pts were heavily pretreated and had aggressive disease: 26% had ≥4 prior lines of systemic therapy (median of 3; range, 1‒8); 34% underwent prior auto-HSCT and 3% prior allo-HSCT; 67% were chemorefractory; and 44% had never achieved CR. 59% required bridging therapy. 22% had LDH ≥500 U/L and 28% had SPD ≥50 cm2 before LD. Outcomes were similar between DLs; therefore, data were pooled. Twenty-five pts were treated in the outpatient setting. Safety analysis showed 79% of pts had grade ≥3 TEAEs, primarily cytopenias (neutropenia, 60%; anemia, 37%; thrombocytopenia, 27%). CRS or NE occurred in 47% of pts. Any grade CRS occurred in 42% of pts at a median onset of 5 days; only 2% had grade ≥3 CRS. NEs occurred in 30% of pts (grade ≥3, 10%) at a median onset of 9 days (Table). 19% of pts received tocilizumab and 21% received corticosteroids for CRS and/or NEs. Four grade 5 TEAEs related to liso-cel and LD occurred (diffuse alveolar damage, pulmonary hemorrhage, multiple organ dysfunction syndrome, cardiomyopathy). Prolonged grade ≥3 cytopenia (based on laboratory assessment at Day 29) was reported in 37% of pts. Safety was similar between age groups, histologies, and pts with organ dysfunction. The study met all primary and secondary efficacy endpoints. Among pts evaluable for efficacy (n=255), ORR was 73% (95% CI, 67‒78); the CR rate was 53% (95% CI, 47‒59). Responses were similar across all pt subgroups (Table). Median DOR was 13.3 mo (95% CI, 8.2‒not reached [NR]) with 10.8 mo of median follow-up; median DOR for pts in CR was NR (13.3‒NR). Median PFS was 6.8 mo (95% CI, 3.3‒11.8). Median OS was 19.9 mo (95% CI, 10.9‒NR). Overall, PFS after liso-cel infusion was substantially longer than PFS from the immediate prior therapy. Conclusions: Liso-cel demonstrated durable clinical activity with a favorable safety profile in this large study of CAR T cell therapy in R/R large B cell NHL. Low incidence and late onset of CRS and NE allowed for outpatient administration. Clinically meaningful efficacy was observed across histologic subgroups and those with poor prognosis, including pts who were refractory, elderly, comorbid, and/or had high tumor burden. Disclosures Abramson: AbbVie Inc, Amgen Inc, Bayer HealthCare Pharmaceuticals, Celgene Corporation, EMD Serono Inc, Genentech, Gilead Sciences Inc, Janssen Biotech Inc, Juno Therapeutics, a Celgene Company, Karyopharm Therapeutics, Kite Pharma Inc, Merck, Novartis, Seattle Gen: Consultancy. Palomba:Kite Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Merck & Co Inc.: Consultancy; MSK (IP for Juno and Seres): Patents & Royalties; Noble Insights: Consultancy; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Seres Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; STRAXIMM: Membership on an entity's Board of Directors or advisory committees; Evelo: Equity Ownership; Hemedicus: Speakers Bureau. Gordon:Gilead: Other: Advisory Board; Bayer: Other: Advisory Board; Juno/Celgene: Other: Advisory Board, Research Funding; Zylem LLC: Other: co-founder; research in nanoparticles in cancer. Lunning:Spectrum: Consultancy; Seattle Genetics: Consultancy; Portola: Consultancy; OncLive: Consultancy; Novartis: Consultancy; Kite: Consultancy; Gilead Sciences, Inc.: Consultancy; DAVA: Consultancy; Bayer: Consultancy; AbbVie: Consultancy; TG Therapeutics: Consultancy, Research Funding; MiRagen: Research Funding; Juno Therapeutics: Consultancy, Research Funding; Janssen Scientific Affairs, LLC: Consultancy, Research Funding; Curis: Research Funding; VANIUM: Consultancy; Verastem: Consultancy. Wang:Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Pharmacyclics: Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; MoreHealth: Consultancy, Equity Ownership; Acerta Pharma: Consultancy, Research Funding; Kite Pharma: Consultancy, Research Funding; Guidepoint Global: Consultancy; BioInvent: Consultancy, Research Funding; VelosBio: Research Funding; Loxo Oncology: Research Funding; Celgene: Honoraria, Research Funding; Juno Therapeutics: Research Funding; Aviara: Research Funding; Dava Oncology: Honoraria. Arnason:Celgene/Juno: Consultancy; Regeneron Pharmaceuticals, Inc.: Consultancy. Mehta:Pharmacyclics: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Spectrum: Consultancy, Speakers Bureau; Imbrium therapeutics: Consultancy; Roche-Genentech: Research Funding; Incyte: Research Funding; Kite/Gilead: Research Funding, Speakers Bureau; Takeda: Research Funding; Rhizen: Research Funding; ADC therapeutics: Research Funding; Forty Seven Inc: Research Funding; Juno/Celgene: Research Funding; Affimed: Research Funding; Seattle Genetics: Research Funding, Speakers Bureau; Astex: Research Funding; TG Therapeutics: Research Funding; miRagen: Research Funding; Kyowa-Kirin: Consultancy, Speakers Bureau; Astra-Zeneca: Speakers Bureau; Sanofi: Consultancy. Maloney:Celgene,Kite Pharma: Honoraria, Research Funding; Juno Therapeutics: Honoraria, Patents & Royalties: patients pending , Research Funding; BioLine RX, Gilead,Genentech,Novartis: Honoraria; A2 Biotherapeutics: Honoraria, Other: Stock options . Andreadis:Juno: Research Funding; Pharmacyclics: Research Funding; Genentech: Consultancy, Employment; Kite: Consultancy; Gilead: Consultancy; Jazz Pharmaceuticals: Consultancy; Roche: Equity Ownership; Novartis: Research Funding; Celgene: Research Funding; Merck: Research Funding. Sehgal:Merck: Research Funding; Juno/Celgene: Research Funding; Kite/Gilead: Research Funding. Ghosh:AstraZeneca: Honoraria, Speakers Bureau; Bristol-Myers Squibb: Honoraria, Speakers Bureau; Gilead: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; SGN: Consultancy, Honoraria, Research Funding, Speakers Bureau; TG Therapeutics: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Research Funding; Genentech: Research Funding; Forty Seven Inc: Research Funding. Albertson:Juno Therapeutics, a Celgene Company: Employment, Equity Ownership. Garcia:Celgene: Employment, Equity Ownership. Kostic:Juno Therapeutics, a Celgene Company: Employment. Li:Juno Therapeutics, a Celgene Company: Employment. Kim:Juno Therapeutics, a Celgene Company: Employment. Siddiqi:TG Therapeutics: Research Funding; Kite, A Gilead Company: Research Funding; Seattle Genetics: Speakers Bureau; Janssen: Speakers Bureau; AstraZeneca: Consultancy, Research Funding, Speakers Bureau; PCYC: Consultancy, Research Funding, Speakers Bureau; Juno Therapeutics: Consultancy, Other: travel support, Research Funding; Celgene: Research Funding; BeiGene: Research Funding.

Epstein-Barr virus (EBV) is associated with Hodgkin lymphoma (HL) and can be detected by in situ hybridization (ISH) of viral nucleic acid (EBER) in tumor cells. We sought to determine whether plasma EBV-DNA could serve as a surrogate for EBER-ISH and to explore its prognostic utility in HL. Specimens from the Cancer Cooperative Intergroup Trial E2496 were used to compare pretreatment plasma EBV-DNA quantification with EBV tumor status by EBER-ISH. A cutoff of >60 viral copies/100 µL plasma yielded 96% concordance with EBER-ISH. Pretreatment and month 6 plasma specimens were designated EBV(-) or EBV(+) by this cutoff. Patients with pretreatment EBV(+) plasma (n = 54) had inferior failure-free survival (FFS) compared with those with pretreatment EBV(-) plasma (n = 274), log-rank P = .009. By contrast, no difference in FFS was observed when patients were stratified by EBER-ISH. Pretreatment plasma EBV positivity was an independent predictor of treatment failure on multivariate analyses. At month 6, plasma EBV(+) patients (n = 7) had inferior FFS compared with plasma EBV(-) patients (n = 125), log-rank P = .007. These results confirm that plasma EBV-DNA is highly concordant with EBER-ISH in HL and suggest that it may have prognostic utility both at baseline and after therapy. This trial was registered at www.clinicaltrials.gov as #NCT00003389.

Uniformly adopted response criteria are essential for assessment of therapies incorporating conventional chemotherapy and chemoimmunotherapy regimens. Recently, immunomodulatory agents, such as immune checkpoint inhibitors, have demonstrated impressive activity in a broad range of lymphoma histologies. However, these agents may be associated with clinical and imaging findings during treatment suggestive of progressive disease (PD) despite evidence of clinical benefit (eg, tumor flare or pseudo-progression). Considering this finding as PD could lead to patients being prematurely removed from a treatment from which they actually stand to benefit. This phenomenon has been well described with checkpoint blockade therapy in solid tumors and anecdotally seen in lymphoma as well. To address this issue in the context of lymphoma immunomodulatory therapy, a workshop was convened to provide provisional recommendations to modify current response criteria in patients receiving these and future agents in clinical trials. The term “indeterminate response” was introduced to identify such lesions until confirmed as flare/pseudo-progression or true PD by either biopsy or subsequent imaging.

Increased tumor-associated macrophages (TAMs) are reported to be associated with poor prognosis in classic Hodgkin lymphoma (CHL). We investigated the prognostic significance of TAMs in the E2496 Intergroup trial, a multicenter phase 3 randomized controlled trial comparing ABVD and Stanford V chemotherapy in locally extensive and advanced stage CHL. Tissue microarrays were constructed from formalin-fixed, paraffin-embedded tumor tissue and included 287 patients. Patients were randomly assigned into training (n = 143) and validation (n = 144) cohorts. Immunohistochemistry for CD68 and CD163, and in situ hybridization for EBV-encoded RNA were performed. CD68 and CD163 IHC were analyzed by computer image analysis; optimum thresholds for overall survival (OS) were determined in the training cohort and tested in the independent validation cohort. Increased CD68 and CD163 expression was significantly associated with inferior failure-free survival and OS in the validation cohort. Increased CD68 and CD163 expression was associated with increased age, EBV-encoded RNA positivity, and mixed cellularity subtype of CHL. Multivariate analysis in the validation cohort showed increased CD68 or CD163 expression to be significant independent predictors of inferior failure-free survival and OS. We demonstrate the prognostic significance of TAMs in locally extensive and advanced-stage CHL in a multicenter phase 3 randomized controlled clinical trial.

We investigated a recent (January 1999 to December 2009) cohort of 95 elderly Hodgkin lymphoma subjects. At diagnosis, median age was 67 years (range, 60-89 years), whereas 61% had significant comorbidity, 26% were unfit, 17% had a geriatric syndrome, and 13% had loss of activities of daily living. Overall response rate to therapy was 85%, whereas incidence of bleomycin lung toxicity was 32% (with associated mortality rate, 25%). With 66-month median follow-up, 2-year and 5-year overall survival were 73% and 58%, respectively (advanced-stage, 63% and 46%, respectively). Most International Prognostic Score factors were not prognostic on univariate analyses, whereas Cox multivariate regression identified 2 risk factors associated with inferior overall survival: (1) age more than 70 years (2.24; 95% CI, 1.16-4.33, P = .02) and (2) loss of activities of daily living (2.71; 95% CI, 1.07-6.84, P = .04). Furthermore, a novel survival model based on number of these risk factors (0, 1, or 2) showed differential 2-year OS of 83%, 70%, and 13%, respectively (P < .0001) and 5-year OS of 73%, 51%, and 0%, respectively (P < .0001).

The RAS/RAF/MEK/ERK signaling pathway has been largely unexplored as a potential therapeutic target in lymphoma. The novel 2nd generation anti-MEK small molecule, AZD6244, down-regulated its direct downstream target, phospho-ERK (pERK) in germinal center and nongerminal center diffuse large B-cell lymphoma (DLBCL) cell lines and primary cells. Similar decreased pERK levels were noted despite constitutive activation (CA) of MEK. Consequently, several lymphoma-related ERK substrates were down-regulated by AZD6244 including MCT-1, c-Myc, Bcl-2, Mcl-1, and CDK1/2. AZD6244 induced time- and dose-dependent antiproliferation and apoptosis in all DLBCL cell lines and fresh/primary cells (IC50 100nM-300nM). Furthermore, AZD6244 resulted in significantly less tumor compared with control in an in vivo DLBCL SCID xenograft model. Cell death was associated with cleaved PARP, caspases-8, -9, and -3, and apoptosis was caspase-dependent. In addition, there was stabilization of FoxO3a, activation of BIM and PUMA, and a significant decrease in c-Myc transcripts. Moreover, siRNA knockdown of BIM abrogated AZD6244-related apoptosis, while shRNA knockdown of ERK minimally sensitized cells. Finally, manipulation of AKT with transfection of OCI-LY3 cells with CA-AKT or through chemical inhibition (LY294002) had minimal effect on AZD6244-induced cell death. Altogether, these findings show that the novel anti-MEK agent, AZD6244, induced apoptosis in DLBCL and that cell death was BIM-dependent.

Background: Pembrolizumab (PEM), a PD-1 inhibitor, is US FDA approved for the treatment of relapsed/refractory cHL based on results of a pivotal trial demonstrating an overall response rate of 69% and complete response (CR) rate of 22%. We hypothesized that PEM monotherapy would result in a higher CR rate (50%) in previously untreated patients owing to greater immunocompetence. Consequently, we initiated a phase 2 clinical trial of upfront sequential PEM and AVD (Adriamycin, Vinblastine, Dacarbazine) chemotherapy. While several of the initial patients had dramatic responses to PEM x's 3 on PET2, they only met Lugano criteria for partial responses. In an attempt to better reflect and quantify the response to checkpoint inhibition, we amended our protocol to include additional analysis of metabolic tumor volume (MTV) and total lesion glycolysis (TLG) which have been investigated as predictors of response in cHL and DLBCL. Herein, we report an interim analysis of toxicity and efficacy, measured by Deauville score, MTV and TLG in the first 13 patients to complete PEM monotherapy. Methods: Patients ≥ 18 years of age with newly diagnosed cHL stages I-IV, including unfavorable early stage disease with at least one risk factor according to the NCCN criteria, were eligible. Patients had a pre-therapy PET-CT, followed by 3 cycles of PEM at 200 mg every 3 weeks and interim PET-CT (PET2) after single agent PEM for primary analysis. Subsequently, patients received 4-6 cycles of AVD chemotherapy based on initial stage. MTV representing the total volume of the metabolically active tumor in a volume of interest (VOI) was calculated using the fixed 41% SUVmax threshold corresponding to the dimensions of the tumor. TLG, combining the volumetric and metabolic information of FDG-PET, was calculated by multiplying the SUVmean of the segmented VOI and the MTV. These measurements were performed using SyngoVia software, Multi-foci segmentation tool (Siemens). Blinded central review of the visually assessed Deauville score was performed, and if different from the report by one of four nuclear medicine radiologists, a second central review was performed to adjudicate. Correlative studies include serum and biopsy samples pre/post PEM to assess immune biomarkers of response. Results: Fifteen patients were enrolled from September 2017, through a data cut off of July 10, 2018, at Northwestern University. Thirteen patients have completed lead-in PEM monotherapy and have undergone PET2. Median age was 30 years (range, 23-77). Eight patients had unfavorable early stage disease and 7 had advanced stage. Early stage risk factors included bulky disease (n=8), B-symptoms (n=5), and elevated ESR (n=5). Overall, therapy was well tolerated. Grade 3 events included lymphopenia (n=1) and diarrhea (n=1). Only one grade 4 immune-related adverse event (transaminitis) occurred, which resolved with steroid therapy and a delay in therapy. PET2 was scored as Deauville 2 or 3 in six cases including three with large mediastinal masses, and as D 4 or 5 in 7 cases with residual activity (Figure 1). PET2 MTV and TLG could be calculated for 12 of 13 cases, (MTV: 42 - 774 cm2, median 134 cm2; TLG: 257 - 5924; median 814). All 12 patients who completed a subsequent scan (PET3) after 2 cycles of AVD are now in a metabolic CR (Deauville 1-3), including all 7 cases with residual activity after PET2. Conclusion: These interim data suggest that upfront PEM x's 3 is highly active in previously untreated cHL. PEM monotherapy resulted in complete metabolic responses in some patients including those with large mediastinal masses, and near complete responses, best represented by the decline in MTV and TLG compared with Deauville scores or Lugano criteria. Our preliminary data suggest that MTV and TLG are useful additional interim indicators of biologic activity when assessing response after PD-1 inhibitor therapy. Disclosures Allen: Merck: Research Funding; Bayer: Consultancy. Evens:Bayer: Consultancy; Janssen: Consultancy; Affimed: Consultancy; Novartis: Consultancy; Tesaro: Research Funding; Abbvie: Consultancy; Seattle Genetics, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Acerta: Consultancy; Pharmacyclics International DMC: Membership on an entity's Board of Directors or advisory committees. Pro:kiowa: Honoraria; Takeda Pharmaceuticals: Honoraria, Other: Travel expenses; portola: Honoraria; Seattle Genetics: Consultancy, Other: Travel expenses, Research Funding. Advani:Millenium: Other: Institutional Research Support; Merck: Other: Institutional Research Support; Kura: Other: Institutional Research Support; Agensys: Other: Institutional Research Support; Takeda: Other: Consultancy/Advisory Role; Roche/Genentech: Other: Consultancy/Advisory Role, Institutional Research Support; Pharmacyclics: Other: Institutional Research Support; Cell Medica: Other: Consultancy/Advisory Role; Kyowa: Other: Consulting/Advisory Role; Janssen Pharmaceutical: Other: Institutional Research Support; Autolus: Other: Consultancy/Advisory Role; Regeneron Pharmaceuticals, Inc.: Other: Institutional Research Support; Seattle Genetics: Other: Consultancy/Advisory role, Institutional Research Support; Bayer Healthcare Pharmaceuticals: Other: Consultancy/Advisory Role; AstraZeneca: Other: Consultancy/Advisory Role; Bristol Myers Squibb: Other: Consultancy/Advisory role and Institutional Research Support; Forty Seven, Inc: Other: Institutional Research Support; Celgene: Other: Institutional Research Support; Gilead/Kite: Other: Consultancy/Advisory Role; Infinity: Other: Institutional Research Support. Winter:Merck: Honoraria, Research Funding.

Introduction: Diffuse large B cell lymphoma (DLBCL) cells have an increased demand for cholesterol and cholesteryl esters to maintain membrane-anchored pro-survival signaling pathways, such as B cell receptor (BCR) signaling. In addition to BCR-mediated stimulation of de novo cholesterol synthesis, another mechanism employed by lymphoma cells to maintain cholesterol and cholesteryl ester homeostasis is by binding cholesterol-rich HDLs via the high-affinity receptor, scavenger receptor type B-1 (SCARB1). We previously reported that, unlike normal B cells, DLBCL cells highly express SCARB1, and that synthetic, cholesterol-poor high-density lipoprotein (HDL)-like nanoparticles (HDL NPs) exquisitely target SCARB1, deplete cellular cholesterol, and induce lymphoma cell death in vitro and in vivo. Given the critical role of cholesterol in maintaining proper membrane organization for BCR-mediated intracellular signaling, we hypothesized that HDL NP binding to SCARB1 and subsequent cellular cholesterol depletion modulates the organization of the cell membrane, reduces intracellular signaling downstream of membrane-anchored pathways like the BCR, and modulates the expression of genes relevant to cholesterol synthesis. Collectively, these mechanisms potently induce lymphoma cell death. Methods: We focused on germinal center (GC) DLBCL and Burkitt's Lymphoma (BL), due to the previously reported sensitivity of the SUDHL4 (GC DLBCL) and Ramos (BL) cell lines to HDL NP-induced cell death. In addition to SUDHL4 and Ramos, we tested the GC DLBCL cell line SUDHL6 and the BL cell lines Raji, Daudi and Namalwa. HDL NPs were synthesized, purified and characterized using standard protocols. Cell viability was quantified using the MTS assay, and total cholesterol levels were measured using the Amplex Red cholesterol assay. A blocking antibody against SCARB1 was used to inhibit binding of HDL NPs to the receptor. Confocal microscopy was used to visualize changes in membrane organization of SUDHL4 and Ramos cells following HDL NP treatment. Changes in the phosphorylation of signaling kinases (e.g. AKT, ERK1/2) following HDL NP treatment was measured using phospho-kinase arrays, phos-flow analysis, and western blot assays. RNA was harvested from cells treated with the HDL NPs for 48 hours and analyzed using Illumina's HT-12 microarray and RT-qPCR. Protein expression changes were measured using western blot assays. Results: HDL NPs potently induced cell death in all of the GC DBLCL and BL cell lines, all of which expressed SCARB1, with HDL NP IC50 values between 1 ~ 5 nM. As expected, HDL NP-induced cell death correlated with reduced total cellular cholesterol levels. Inhibition of HDL NP binding to SCARB1 by antibody blockade protected cells from HDL NP-induced cell death. HDL NP treatment induced a reorganization of the plasma membrane in SUDHL4 and Ramos cells, resulting in clustering of SCARB1, a phenomenon not seen in cholesterol-rich human HDL or saline controls. HDL NP treatment led to a decrease in the phosphorylation of a number of kinases downstream of BCR signaling, including AKT, ERK1/2, LCK and LYN over time. HDL NPs demonstrated synergy with small molecule inhibitors of various signaling kinases, such as ATK (inhibitor = GDC-0068) and SYK (inhibitor = R406), in Ramos and SUDHL4 cells. By microarray analysis and RT-qPCR, HDL NPs up-regulated a number of cholesterol biosynthesis genes, as well as the cell cycle inhibitor p21 and the pro-apoptotic protein APOPT1. Conclusions: These data demonstrate that HDL NPs bind SCARB1, altering the organization of the plasma membrane and reducing cellular cholesterol levels. Collectively, this results in decreased membrane-anchored pro-survival signaling, changes in gene expression pathways, and, ultimately, lymphoma cell death. Enhancing cholesterol depletion strategies, such as the combination of the targeted cholesterol depletion agent HDL NP with small molecule inhibitors of signaling kinases (e.g. AKT and SYK inhibitors), represents a novel and targeted therapeutic strategy for DLBCL and may be broadly applicable to other malignancies dependent on cholesterol homeostasis and membrane-anchored signaling pathways. Disclosures Karmali: Gilead: Speakers Bureau; AstraZeneca: Speakers Bureau. Thaxton:AuraSense: Other: Co-founder of the biotech company AuraSense.

Our laboratory has recently discovered a novel candidate oncogene, MCT-1, amplified in human T-cell lymphoma and mapped to chromosome Xq22-24. This region is amplified in a subset of primary B-cell non-Hodgkin lymphoma (NHL), suggesting that increased copy number of a gene(s) located in this region confers a growth advantage to some primary human lymphomas. We examined a diverse panel of lymphoid malignancies for the expression of MCT-1. We demonstrated that there are significantly increased levels of MCT-1 protein in a panel of T-cell lymphoid cell lines and in non-Hodgkin lymphoma cell lines. Furthermore, we identified a subset of primary diffuse large B-cell lymphomas that exhibited elevated levels of MCT-1 protein. Interestingly, all transformed follicular lymphomas in our study demonstrated elevated protein levels of MCT-1. There was no detectable MCT-1 protein in leukemic cells from patients with chronic lymphocytic leukemia or in any healthy lymphoid tissue examined. Lymphoid cell lines overexpressing MCT-1 exhibited increased growth rates and displayed increased protection against apoptosis induced by serum starvation when compared with matched controls. We found that MCT-1—overexpressing cells show constitutively higher levels of phosphorylated PKB/Akt protein, especially under serum starvation. Activation of survival pathways may be an additional function of the MCT-1 gene. Our data suggest that high levels of MCT-1 protein may be associated with a high-risk subset of lymphoid neoplasms and may further support the potential role of MCT-1 in promoting human lymphoid tumor development. (Blood. 2003;102: 297-302)

Background: Standard therapeutic regimens for older HL patients (pts) may confer significantly increased toxicity and inferior survival compared with younger pts. Reported complete remission (CR) rates for older pts are 45-76% with 2-year (yr) progression-free survival (PFS) rates of 50-71% (eg, Evens et al. Blood 2012). With a goal of improving outcomes for older cHL pts, this multicenter phase 2 study tested Bv given sequentially before and after standard AVD chemotherapy. Methods: Older pts (aged ≥60 yrs) with stage IIB-IV, untreated cHL were eligible. Pts received 2 'lead-in' doses of single-agent Bv 1.8 mg/kg (q 3 weeks) followed by 6 cycles of standard AVD. Supportive antibiotics were encouraged & granulocyte growth factor was allowed. Responding pts proceeded to consolidation (Cx) therapy with 4 Bv cycles. Study design was a Simon 2-stage; the primary endpoint was CR rate after AVD (ie, prior to Bv Cx) using revised Cheson with FDG-PET; pts must have received 2 cycles of AVD to be evaluable for response. The study was considered promising if >70% of evaluable pts demonstrated CR. Univariate & multivariate analyses (MVA) were performed using Cox proportional hazard regression for associations between lab and clinical factors (including co-morbidities assessed by the Cumulative Illness Rating Scale (CIRS)) with survival. Results: 48 pts enrolled to the study (8/2012-8/2016) with 41 being evaluable for response. Characteristics for all pts included: median age 69 yrs (60-88); 30M:18F; median ECOG PS of 1 (21% PS=2); 82% stage III/IV disease (bone marrow involved 23%); and IPS 3-7 in 60%. No pts had loss of activities of daily living (ADL) at baseline, while 12% had loss of instrumental ADLs. Median CIRS co-morbidity score at baseline was 6 (0-20). 6 pts received 1 pt were neutropenia (60%); infection (15%), febrile neutropenia (8%); transaminitis (6%); renal insufficiency (6%); urinary infection (6%); pneumonia (6%); hyponatremia (6%); fatigue (6%); febrile neutropenia (6%); diarrhea (4%); pancreatitis (4%), & peripheral neuropathy (PN) (4%). 33% of all pts experienced grade 2 PN (6% motor/27% sensory); the majority were reversible. Treatment related mortality on study was 2% (n=1 pancreatitis). Reasons for study discontinuation were: completed treatment (52%); toxicity/AEs (33%); withdrew consent/refused additional treatment (9%); & progressive disease or death (6%). Finally, for pt prognostication, increasing age (continuous) (P=0.005), female (P=0.05) & increased CIRS (continuous) (P=0.006) were associated with inferior PFS on univariate analysis; on MVA, only increasing age remained significant (HR 1.19 per yr >60, 95%CI 1.02-1.37, P=0.02). Conclusions: Bv-AVD incorporating Bv sequentially before and after chemotherapy represents among the best-reported outcomes to date for untreated older cHL pts. Efforts to maintain these robust remission and survival rates, but with less toxicity, should be a focus of ongoing investigation. This should include response-adapted design and integration of other novel agents (eg, checkpoint inhibitors), especially for pts with advanced ages and/or multiple co-morbidities. Disclosures Evens: Novartis: Consultancy; Affimed: Consultancy; Merck: Consultancy; Kite Pharma: Consultancy; Amgen: Consultancy; Celgene: Consultancy; Millennium: Consultancy; AbbVie: Consultancy; Pharmacyclics: Consultancy; Seattle Genetics: Consultancy; • Spectrum Pharmaceuticals: Consultancy. Advani: Spectrum: Consultancy; Gilead: Consultancy; Agensys: Research Funding; Bayer Healthcare Pharmaceuticals: Research Funding; Merck: Research Funding; Celgene: Research Funding; Seattle Genetics: Research Funding; Kura: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Nanostring: Consultancy; FortySeven: Research Funding; Janssen: Research Funding; Cell Medica: Research Funding; Millennium: Research Funding; Pharmacyclics: Consultancy; Sutro: Consultancy; Juno Therapeutics: Consultancy; Pharmacyclics: Research Funding; Infinity: Research Funding; Genentech: Research Funding. Fanale: ONYX: Research Funding; CELGENE: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; TAKEDA: Honoraria, Research Funding; AMGEN: Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; SEATTLE GENETICS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; GENENTECH: Research Funding; MERCK: Membership on an entity's Board of Directors or advisory committees, Research Funding; MOLECULAR TEMPLATES: Research Funding; ADC THERAPEUTICS: Research Funding. Winter: Merck: Research Funding; Glaxo-Smith-Kline: Research Funding. Gordon: Janssen: Other: Data Monitoring Committee. Hamlin: Celgene: Consultancy, Honoraria; Portola: Consultancy, Honoraria, Other: research support; Incyte: Other: research support; Gilead: Consultancy, Honoraria; Novartis: Other: research support; Seattle Geneitcs: Other: research support.

Introduction: Follicular lymphoma (FL) is characterized by an indolent clinical course, but patients with this disease bear a risk of transformation to diffuse large B-cell lymphoma (DLBCL) or high-grade B-cell lymphoma (HGBL). DLBCL transformed from FL (tDLBCL) traditionally has been associated with an aggressive course and a post-transformation survival of 0.6-1.7 years. However, a more recent study showed longer survivals in these patients, challenging the notion that transformation universally portends a poor prognosis in the immunotherapy era. Presence of concurrent FL at the time of diagnosis of DLBCL (cDLBCL/FL) also raises the possibility of transformation, but its clinical significance has not been elucidated in the literature. In this study, we analyzed and compared outcomes of tDLBCL, cDLBCL/FL, and de novo DLBCL. We also characterized the prevalence of MYC/BCL2/BCL6 gene rearrangements in tDLBCL and cDLBCL/FL cohorts and evaluated the impact of dual rearrangements (double hit, DH) on clinical outcomes. Methods: Patients diagnosed with DLBCL or B cell lymphoma unclassifiable with features intermediate between DLBCL and Burkitt lymphoma, also known as HGBL (BCLU/HGBL), treated at Northwestern University or University of Pennsylvania from 1/2010 to 7/2016 were included. Patients with Burkitt lymphoma, primary CNS and HIV-associated lymphoma were excluded. Transformation was defined as presence of DLBCL/ BCLU/HGBL in cases with an antecedent diagnosis of FL by at least 6 months. We divided our cohort into three groups: 1. De novo DLBCL or BCLU/HGBL with no prior history of FL (dDLBCL) 2. Transformed FL (tDLBCL) and 3. DLBCL or BCLU/HGBL with concurrent FL (cDLBCL/FL). Progression free survival (PFS) was defined as time from diagnosis to radiographic progression, regimen change, death or last follow-up. Overall survival (OS) was defined as time from diagnosis to death or last follow-up. Kaplan-Meier (KM) survival analyses, using a log-rank p-values were performed for PFS and OS to compare the three diagnosis groups (dDLBCL, tDLBCL, and cDLBCL; alpha=0.05) and pairwise comparisons of combinations of diagnosis (dDLBCL and tDLBCL+cDLBCL) and double hit status (accounting for multiple comparisons with a Bonferroni corrected alpha=0.013). Fluorescence in situ hybridization for MYC, BCL2 and BCL6 rearrangements was performed using break-apart probes per the policy of each institution. Results: A total of 293 pts, including 233 dDLBCL, 37 tDLBCL, and 23 cDLBCL/FL were included. 50% of the tDLBCL received at cytotoxic chemotherapy before transformation for precedent FL. Age and sex distribution, as well as clinical characteristics including stage, ECOG performance status, IPI score, and primary refractoriness were similar amongst the three groups. LDH was more likely to be elevated in dDLBCL (75%), as compared to tDLBCL(63%) and cDLBCL/FL (47%)( p=0.02%). Additionally, non-bone marrow extra-nodal disease was seen more often in dDLBCL (72%), as compared with tDLBCL (53%) and cDLBCL/FL (43%)( p Conclusions: DLBCLs transformed from FL or with concurrent diagnosis of FL (composite lymphoma) demonstrated similar clinical outcomes in our study. However, dual rearrangements are more prevalent in these patients and drive inferior survival similar to DH status in de novo DLBCL. Figure 1 Figure 1. Disclosures Landsburg: Curis: Consultancy, Research Funding; Takeda: Research Funding. Winter: Merck: Research Funding; Glaxo-Smith-Kline: Research Funding. Pro: Seattle Genetics: Consultancy; Takeda: Consultancy, Research Funding; Celgene: Consultancy, Research Funding. Gordon: Janssen: Other: Data Monitoring Committee. Karmali: Celgene: Speakers Bureau. Kaplan: Millennium: Research Funding; Takeda: Research Funding; Seattle Genetics: Research Funding; Janssen: Research Funding.