Vose, Julie M.

8533 Background: Mantle cell lymphoma (MCL) is an aggressive form of non-Hodgkin lymphoma (NHL) with poor prognosis. The immunomodulatory agent lenalidomide shows consistent activity with tolerable safety in multiple phase II studies of relapsed/refractory aggressive NHL (NHL-002 and NHL-003) and MCL post-bortezomib (MCL-001). This pooled analysis further examined the efficacy and safety of single-agent lenalidomide in patients with relapsed/refractory MCL. Methods: Single-agent lenalidomide was given 25 mg/d PO on days 1-21 of 28-day cycles as tolerated for 52 weeks (NHL-002) or until disease progression (NHL-003 and MCL-001). All MCL patients received ≥1 prior treatment, including bortezomib in MCL-001. Efficacy data were examined by independent central review for MCL-001 and NHL-003 and by investigators for NHL-002. Results: 206 patients with relapsed/refractory MCL were studied. The median age was 67 y (range 33-84; 63% ≥65 y), 91% stage III/IV disease and 51% had received ≥4 prior regimens (76% prior bortezomib). Overall response rate (ORR) with lenalidomide was 32% (10% CR/CRu), with a median time to response of 2.1 months and median duration of response (DOR) of 16.6 months (not yet reached in patients with CR/CRu; Table). Kaplan-Meier estimates for median PFS and OS were 5.4 and 23.9 months, respectively. Mean daily dose of lenalidomide was 21 mg. Grade 3/4 AEs included neutropenia (44%), thrombocytopenia (29%), anemia (11%), and fatigue (7%). Other any-grade AEs included tumor flare reaction (7%), venous thromboembolic events (7%), and invasive second primary malignancies (3%). Conclusions: Lenalidomide produced rapid and durable responses in patients with relapsed/refractory MCL, and exhibited a predictable safety profile among 3 phase II studies of lenalidomide in heavily pretreated patients, including prior treatment with bortezomib. Clinical trial information: MCL-001: NCT00737529; NHL-002: NCT00179660; NHL-003: NCT00413036. [Table: see text]

8060 Background: ENKL is a rare and aggressive subtype of peripheral T-cell lymphoma. Due to its geographic predilection there is a paucity of data on clinical experiences from non-Asian countries. The purpose of this study was to analyze characteristics and outcomes of patients (pts) with ENKL identified from major academic centers in NA. Methods: Pts with newly diagnosed CD56+ ENKL were retrospectively identified. Analyses included disease characteristics, ethnicity, therapy, and outcomes. Results: 115 pts (63.5% Caucasian, 20% Asian, 16.5% other) were identified across 10 centers diagnosed between 5/1990-5/2011 (Era 1: pre-2000, n=16; Era 2: 2000-2005, n=45; Era 3: post-2005, n=54). Median age was 52 years (19-88). 75 (65%) had stage I/II disease and were treated with combined modality therapy (CMT) n=48, chemotherapy (CT) n=14 or radiotherapy (RT) n=14. 40 pts had stage III/IV disease and were treated with CT (n=23), CMT (n=12) or RT (n=5). CT regimens used alone or in CMT were either anthracycline-based (n=68) or other (n=29). 63% of stage I/II pts and 40% with stage III/IV achieved complete remission (CR). 30 pts underwent a stem cell transplant (SCT); 14 in first CR and 16 at progression/relapse (autologous, n=21; allogeneic, n=9). Pts with stage I/II disease had a better progression-free survival (PFS) and overall survival (OS) compared with stage III/IV (12 vs 5.2 months (p=0.003) and 41.5 vs 8.9 months (p<0.0001), respectively). For all stages, treatment with CMT compared with CT or RT alone was also associated with better PFS and OS, 18.0 vs 3.9 months (p<0.0001), and 41.5 vs 10.2 months (p=0.002) respectively. Non-anthracycline-based regimens were associated with better PFS (p=0.001) and OS (p=0.045). No survival differences were seen between Asian and non-Asian pts. Conclusions: This series represents one of the largest experiences of ENKL in NA. Our data are consistent with Asian studies in: 1) majority of pts present with early stage disease; 2) overall poor outcome; 3) superiority of CMT and non-anthracycline regimens. Advances in understanding biology and international collaborative efforts are required to improve outcome in this rare entity.

8066 Background: Lenalidomide, an immunomodulatory drug, is approved in the US for treatment of relapsed/refractory multiple myeloma and myelodysplastic syndromes associated with a deletion 5q[31] cytogenetic abnormality. Lenalidomide also has activity in chronic lymphocytic leukemia and cutaneous T-cell lymphoma. This study was designed to assess the safety and efficacy of lenalidomide monotherapy in patients with relapsed/refractory indolent non-Hodgkin's lymphoma (NHL). Methods: Patients with relapsed/refractory indolent NHL with measurable disease after at least 1 prior treatment regimen were eligible. Patients received 25 mg lenalidomide orally once daily on Days 1–21 every 28 days and continued therapy for 52 weeks as tolerated or until disease progression. Response and progression were evaluated using the IWLRC methodology. Results: As of enrollment cut-off, 43 patients received drug and 27 were evaluable for response. The median age was 63 (43–82) and 12 were female. Histology was small lymphocytic lymphoma [SLL] (n=12), follicular center lymphoma grades 1,2 [FCL] (n=12) and nodal marginal B-cell lymphoma [NML] (n=3). Median time from diagnosis to lenalidomide was 4.3 (0.4- 24) years and median number of prior treatment regimens was 3 (1–17). Seven patients (26%) exhibited an objective response (2 complete responses (CR), 1 complete response unconfirmed (CRu) and 4 partial responses (PR)), 9 had stable disease (SD) for a tumor control rate (TCR) of 59% and 11 progressive disease (PD). Responses were produced in each of the indolent histologic subtypes studied: SLL (3/12), FCL (3/12) and NML (1/3). Since most responses develop at ≥ 4 months, additional responses may be seen in early SD patients with longer follow-up. Five patients (12%) exhibited Grade 4 neutropenia, and Grade 3 adverse events were neutropenia (16%) and thrombocytopenia (14%). Conclusion: Lenalidomide oral monotherapy is active with manageable side effects in relapsed/refractory indolent NHL. [Table: see text]

Introduction MCL is a rare cancer, and current clinical practice guidelines list multiple reasonable treatment options for MCL. It can be challenging to select treatment (Tx) that optimizes outcomes for patients with a mixture of presenting features. In 2014, we developed an online MCL decision support tool designed to provide expert guidance on optimal treatment for defined patient scenarios. An analysis of the 2014 tool showed that Tx recommendations of community healthcare providers (HCPs) did not consistently align with experts for many patients with MCL (Gopalsamy, et al. Leuk Lymphoma. 2019 Mar 8:1-9). Here we report data from an updated version (2018) of this tool that captures evolving practice patterns among experts and community HCPs and the differences between these 2 groups. Methods In September 2018, a panel of 5 experts provided Tx recommendations for 240 patient scenarios in newly diagnosed or relapsed/refractory MCL. These distinct scenarios were defined by patient and disease characteristics that the experts considered important when making treatment choices, including disease setting, patient age and fitness, cytogenetic information, LDH and Ki67 levels, and information on any previous lines of therapy. To use the tool, HCPs entered specific patient/disease characteristics using expert-defined options along with the Tx planned for each case. The users were then shown the 5 MCL expert recommendations and were asked to indicate the impact of the expert recommendations on their planned Tx approach. Results A total of 387 HCPs entered 654 patient scenarios in the 2018 online tool. For HCPs who answered an optional question on how many patients with MCL they treat per year (n = 145), 81% indicated that they treated 10 or fewer patients with MCL per year, highlighting the rarity of this disease and lack of experience among many HCPs. Furthermore, 74% of these HCPs indicated that they refer &lt; 50% of their patients with MCL for clinical trials or to academic institutions for treatment. Among experts, the primary consensus for initial Tx recommendations for younger, fit patients with MCL were bendamustine/rituximab (BR) and R-HyperCVAD in both 2014 and 2018. In comparison, HCPs chose these 2 regimens for a minority of these patients with newly diagnosed MCL in both editions of the tool. For older or unfit patients, experts predominantly recommended BR (85% in 2014 and 75% in 2018), whereas only 35% to 40% of HCPs would choose this regimen in this setting (Table). Of note, nearly 20% of the HCPs indicated that they would recommend a very aggressive chemotherapy regimen for older or unfit patients. For patients with disease progression after chemoimmunotherapy, the recommendation of ibrutinib-based therapy increased among experts from 2014 to 2018 from 66% to 100%. By contrast, the percentage of HCPs using ibrutinib-based therapy remained low at 29% or 37% in the 2014 and 2018 tools, respectively. Another 14% of HCPs selected acalabrutinib, another approved BTK inhibitor, in 2018. In addition, approximately 20% of HCPs in both 2014 and 2018 were unsure of the optimal use of additional therapy (eg, ASCT or maintenance therapy) for their patients. Among users who answered an optional question on the tool's clinical impact, 47% indicated the expert recommendations changed their planned Tx and 38% indicated that expert recommendations confirmed their approach. Conclusions The analysis of data from this online tool found several areas of expert consensus regarding Tx for patients with MCL, particularly for patients who are progressing after initial chemoimmunotherapy. However, practice patterns of community HCPs did not align with expert recommendations for the majority of cases entered into the tool. The consistent Tx gap between practice patterns of community HCPs and expert recommendations over this time period suggests a continued need for online decision tools like this and other innovative approaches to involve experts in the care of patients with MCL. A detailed comparison of expert and user data from the online tool will be presented. Disclosures Ansell: LAM Therapeutics: Research Funding; LAM Therapeutics: Research Funding; Affimed: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Affimed: Research Funding; LAM Therapeutics: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Trillium: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Trillium: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; Seattle Genetics: Research Funding; LAM Therapeutics: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Mayo Clinic Rochester: Employment; Trillium: Research Funding; Seattle Genetics: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Regeneron: Research Funding; Mayo Clinic Rochester: Employment; Bristol-Myers Squibb: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Affimed: Research Funding; Affimed: Research Funding; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding. Leonard:Nordic Nanovector: Consultancy; Karyopharm Therapeutics: Consultancy; BeiGene: Consultancy; Sutro Biopharma: Consultancy; Gilead: Consultancy; MorphoSys: Consultancy; Merck: Consultancy; Nordic Nanovector: Consultancy; Akcea Therapeutics: Consultancy; MorphoSys: Consultancy; Miltenyi: Consultancy; Epizyme, Inc: Consultancy; AstraZeneca: Consultancy; Bayer Corporation: Consultancy; Celgene: Consultancy; AstraZeneca: Consultancy; ADC Therapeutics: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; Gilead: Consultancy; Bayer Corporation: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; Celgene: Consultancy; Karyopharm Therapeutics: Consultancy; Sutro Biopharma: Consultancy; Epizyme, Inc: Consultancy; Merck: Consultancy; Sandoz: Consultancy; Akcea Therapeutics: Consultancy; Miltenyi: Consultancy; Sandoz: Consultancy; ADC Therapeutics: Consultancy; BeiGene: Consultancy. Vose:Acerta Pharma: Honoraria, Other: Grants, Research Funding; Bristol-Meyers Squibb Company: Research Funding; Celgene Corporation: Research Funding; Incyte Corporation: Research Funding; Kite Pharma: Honoraria, Other: Grants, Research Funding; Novartis: Research Funding; Seattle Genetics: Research Funding; AbbVie: Consultancy, Honoraria; Epizyme: Consultancy, Honoraria; Legend Pharmaceuticals: Honoraria. Wang:BioInvent: Consultancy, Research Funding; Dava Oncology: Honoraria; Aviara: Research Funding; Juno Therapeutics: Research Funding; Celgene: Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; Pharmacyclics: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; VelosBio: Research Funding; Acerta Pharma: Consultancy, Research Funding; Kite Pharma: Consultancy, Research Funding; Guidepoint Global: Consultancy; MoreHealth: Consultancy, Equity Ownership; Loxo Oncology: Research Funding. Flowers:BeiGene: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Denovo Biopharma: Consultancy; Millenium/Takeda: Research Funding; V Foundation: Research Funding; Bayer: Consultancy; Acerta: Research Funding; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy, Research Funding; TG Therapeutics: Research Funding; Burroughs Wellcome Fund: Research Funding; Eastern Cooperative Oncology Group: Research Funding; National Cancer Institute: Research Funding; Optimum Rx: Consultancy; Spectrum: Consultancy; Pharmacyclics/Janssen: Consultancy, Research Funding; AstraZeneca: Consultancy; Gilead: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Karyopharm: Consultancy.

Introduction Brentuximab vedotin (BV) targets CD30, a receptor expressed on the Reed-Sternberg cells of classic Hodgkin lymphoma (cHL). Nivolumab (Nivo) restores antitumor immunity by blocking the PD-1 receptor on activated T-cells. In this phase 1/2 study, combination treatment (tx) with BV + Nivo demonstrated durable efficacy in patients (pts) with relapsed/refractory (R/R) cHL (Herrera, Blood 2018; NCT02572167). Biomarkers consistent with innate and adaptive immune activation were observed in the peripheral blood of pts treated with the combination regimen. Herein, we associate biomarkers in the peripheral blood with clinical response, and present follow-up results for pts who received BV + Nivo under staggered and concurrent dosing schedules. Methods Enrolled pts had cHL that relapsed or was refractory to frontline chemotherapy. In Parts 1 and 2 (staggered dosing), pts received up to 4 cycles of BV 1.8 mg/kg and Nivo 3.0 mg/kg given on Days 1 and 8 of Cycle 1, respectively, and together on Day 1 of Cycles 2-4. Pts in Part 3 (concurrent dosing) received the same dose of both agents on Day 1 of all 4 cycles. After investigators assessed response (Cheson 2014, with the incorporation of LYRIC [Cheson 2016] for pts in Part 3), pts could undergo ASCT. Results Demographics and baseline characteristics were similar across all treated pts (N=91) in the staggered and concurrent dosing cohorts; median age 34 years (yrs, range; 18-69), 42% with primary refractory disease, and 30% with relapse within 1 yr of frontline therapy. All 91 pts are off-tx and have been observed through the 100-day safety reporting period. A total of 86 pts (92%) completed all 4 cycles of BV + Nivo. Early tx discontinuations were due to; AE (peripheral neuropathy and increased GGT [1 pt each]), progressive disease (PD), investigator decision, and pt decision (1 pt each). Most common AEs prior to ASCT or additional salvage therapy were nausea (52%) and infusion-related reactions (IRRs, 43%). Excluding IRRs, 14% of pts had immune-related AEs requiring tx with systemic steroids, including rash (8%), pneumonitis (4%), and AST increased, diarrhea, and Guillain-Barre syndrome (1% each). The ORR for all-treated pts was 85%, with 67% complete response (CR). A total of 67 pts (74%) underwent ASCT after tx with BV + Nivo. There were 22 pts who received additional salvage therapy after BV + Nivo (7 PD, 6 partial response, 5 stable disease, and 4 CR at EOT), 17 of whom later underwent ASCT. At a median of 22.6 months (range; 1.2, 41.2) from the start of tx, the estimated 2-yr PFS rate in all treated pts was 78%, and for pts who underwent ASCT after tx with BV + Nivo was 91% (Figure 1). At 2 years, the estimated OS rate for all treated pts was 93%. Staggered and concurrent dosing of BV + Nivo resulted in increased levels of activated and dividing CD4+ T cells, activated and dividing CD8+ T cells (concurrent dosing-only), regulatory T cells (Tregs), and circulating plasmablasts in blood. We did not observe any associations between the magnitude of these changes and clinical response. Pts with CR exhibited trends for higher pre-tx blood levels of CD30+ Tregs and CD30+ Th subsets compared to pts without CR, suggesting BV depletion of these populations may have a role in the clinical mode of action of BV + Nivo. Although pre-tx levels of cytotoxic lymphocytes (CTLs) in blood did not differentiate pts with CR from other pts, pts in the lower quartile of pre-tx CTL levels showed significantly shorter PFS than other pts, suggesting a potential association between CTLs and disease control. Changes in blood cytokine and chemokine levels were observed after BV + Nivo, including increased levels of IL-18, IP-10, I-TAC, and sCD30, and decreased levels of TARC, IL-2Ra, and IL-6. Our analyses support strong correlations between pre-tx cytokine/chemokine levels and clinical benefit including trends linking lower pre-tx levels of IL-18, I-TAC, and IL-2RA to achieving CR and longer PFS. Conclusion BV + Nivo, both staggered and current dosing, showed tolerability and high CR rates with durable remissions among pts with R/R cHL. Analysis of blood biomarkers identified trends potentially linking baseline levels of CD30+ immune cells and the baseline pt inflammatory state with the activity of BV + Nivo. Together, these encouraging results support further investigation of BV + Nivo as initial salvage therapy in pts with R/R cHL. Figure 1 Disclosures Moskowitz: Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Erytech Pharma: Consultancy; Erytech Pharma: Consultancy; ADC Therapeutics: Consultancy; Merck: Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Merck: Research Funding; Merck: Research Funding; Cell Medica: Consultancy; Takeda Pharmaceuticals: Consultancy; Merck: Research Funding; ADC Therapeutics: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; Erytech Pharma: Consultancy; Takeda Pharmaceuticals: Consultancy; Incyte: Research Funding; Merck: Research Funding; Merck: Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Cell Medica: Consultancy; Takeda Pharmaceuticals: Consultancy; Cell Medica: Consultancy; ADC Therapeutics: Consultancy; Incyte: Research Funding; Takeda Pharmaceuticals: Consultancy; Takeda Pharmaceuticals: Consultancy; Merck: Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Cell Medica: Consultancy; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Takeda Pharmaceuticals: Consultancy; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Cell Medica: Consultancy; miRagen Therapeutics Inc: Consultancy, Research Funding; Incyte: Research Funding; Takeda Pharmaceuticals: Consultancy; Seattle Genetics: Consultancy, Honoraria, Research Funding; Takeda Pharmaceuticals: Consultancy; Cell Medica: Consultancy; ADC Therapeutics: Consultancy; Erytech Pharma: Consultancy; Erytech Pharma: Consultancy; Erytech Pharma: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; Erytech Pharma: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Incyte: Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Incyte: Research Funding; Cell Medica: Consultancy; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Erytech Pharma: Consultancy; Takeda Pharmaceuticals: Consultancy; Takeda Pharmaceuticals: Consultancy; Merck: Research Funding; Takeda Pharmaceuticals: Consultancy; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Incyte: Research Funding; Cell Medica: Consultancy; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Incyte: Research Funding; ADC Therapeutics: Consultancy; Merck: Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; ADC Therapeutics: Consultancy; Incyte: Research Funding; Incyte: Research Funding; Cell Medica: Consultancy; Incyte: Research Funding; ADC Therapeutics: Consultancy; Erytech Pharma: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; Erytech Pharma: Consultancy; Takeda Pharmaceuticals: Consultancy; Takeda Pharmaceuticals: Consultancy; Cell Medica: Consultancy; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Takeda Pharmaceuticals: Consultancy; Cell Medica: Consultancy; Erytech Pharma: Consultancy; Seattle Genetics: Consultancy, Honoraria, Research Funding; Erytech Pharma: Consultancy; Seattle Genetics: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Merck: Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Merck: Research Funding; Cell Medica: Consultancy; Seattle Genetics: Consultancy, Honoraria, Research Funding; Incyte: Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Incyte: Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Incyte: Research Funding; ADC Therapeutics: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; Erytech Pharma: Consultancy; Erytech Pharma: Consultancy; ADC Therapeutics: Consultancy; Incyte: Research Funding; ADC Therapeutics: Consultancy; miRagen Therapeutics Inc: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; ADC Therapeutics: Consultancy; ADC Therapeutics: Consultancy; ADC Therapeutics: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Cell Medica: Consultancy; Cell Medica: Consultancy; Seattle Genetics: Consultancy, Honoraria, Research Funding; Merck: Research Funding; Incyte: Research Funding; Merck: Research Funding; Merck: Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Erytech Pharma: Consultancy; Takeda Pharmaceuticals: Consultancy; ADC Therapeutics: Consultancy; Cell Medica: Consultancy; Seattle Genetics: Consultancy, Honoraria, Research Funding; Merck: Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; ADC Therapeutics: Consultancy; Seattle Genetics: Consultancy, Honoraria, Research Funding. Advani:Celmed: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Forty-Seven: Research Funding; Infinity Pharma: Research Funding; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead Sciences, Inc./Kite Pharma, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Regeneron: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kyowa Kirin Pharmaceutical Developments, Inc.: Consultancy; Merck: Research Funding; Kura: Research Funding; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Autolus: Consultancy, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Agensys: Research Funding; Cell Medica, Ltd: Consultancy; Stanford University: Employment, Equity Ownership; Seattle Genetics: Consultancy, Research Funding; Millennium: Research Funding; Janssen: Research Funding; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Bartlett:Affimed Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Celgene: Research Funding; Dynavax: Research Funding; Forty-Seven: Research Funding; Genentech: Research Funding; Gilead: Research Funding; Immune Design: Research Funding; Janssen: Research Funding; Kite Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Medimmune: Research Funding; Merck: Research Funding; Millennium: Research Funding; Novartis: Research Funding; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Seattle Genetics, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Vose:Acerta Pharma: Honoraria, Other: Grants, Research Funding; Bristol-Meyers Squibb Company: Research Funding; Celgene Corporation: Research Funding; Incyte Corporation: Research Funding; Kite Pharma: Honoraria, Other: Grants, Research Funding; Novartis: Research Funding; Seattle Genetics: Research Funding; AbbVie: Consultancy, Honoraria; Epizyme: Consultancy, Honoraria; Legend Pharmaceuticals: Honoraria. Ramchandren:Genentech: Research Funding; Seattle Genetics, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Research Funding; Pharmacyclics LLC, an Abbvie company: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; Sandoz-Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees. Feldman:Takeda: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding, Speakers Bureau; Seattle Genetics: Consultancy, Honoraria, Other: Travel expenses, Speakers Bureau; AbbVie: Honoraria, Other: Travel expenses, Speakers Bureau; Pharmacyclics: Honoraria, Other: Travel expenses, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Kite Pharma: Honoraria, Other: Travel expenses, Speakers Bureau; Bayer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding; Cell Medica: Research Funding; Roche: Research Funding; Corvus: Research Funding; Eisai: Research Funding; Kyowa Hakko Kirin: Research Funding; Pfizer: Research Funding; Portola Pharma: Research Funding; Roche: Research Funding; Trillium: Research Funding; Viracta: Research Funding. LaCasce:BMS: Consultancy; Research to Practice: Speakers Bureau; Humanigen: Consultancy; Seattle Genetics: Consultancy, Research Funding. Christian:Bristol-Myers Squibb: Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Membership on an entity's Board of Directors or advisory committees, Research Funding; Cephalon: Research Funding; Janssen: Research Funding; Immunomedics: Research Funding; Celgene: Research Funding; Acerta: Research Funding; Triphase: Research Funding; Millennium Pharmaceuticals Inc: Research Funding; Merck: Research Funding. Ansell:Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Affimed: Research Funding. Moskowitz:ADC Therapeutics: Research Funding; Merck: Consultancy, Research Funding; Seattle Genetics, Inc.: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Celgene: Consultancy; Pharmacyclics: Research Funding. Brown:Seattle Genetics, Inc.: Employment, Equity Ownership. Taft:Seattle Genetics, Inc.: Employment, Equity Ownership. Ansari:Seattle Genetics, Inc.: Employment, Equity Ownership. Zak:Seattle Genetics, Inc.: Employment, Equity Ownership. Sacchi:Seattle Genetics, Inc.: Research Funding. Manley:Seattle Genetics: Employment, Equity Ownership. Herrera:Merck: Consultancy, Research Funding; AstraZeneca: Research Funding; Adaptive Biotechnologies: Consultancy; Pharmacyclics: Research Funding; Immune Design: Research Funding; Kite Pharma: Consultancy, Research Funding; Genentech, Inc.: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Gilead Sciences: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding.

Introduction: Axicabtagene Ciloleucel (axi-cel), a CD19 chimeric antigen receptor (CAR) T-cell therapy, was approved for the treatment of relapsed/refractory aggressive B-cell non-Hodgkin lymphoma in October, 2017. In the ZUMA-1 trial leading to axi-cel FDA approval, patients (pts) with prior or active secondary central nervous system (CNS) lymphoma involvement were excluded. A recent publication of 8 pts with secondary CNS lymphoma who underwent Tisagenlecleucel CAR T cell therapy was reported (Frigault M.J.2019). Since the two FDA approved CAR T cell products have a different neurotoxicity profile, understanding outcomes of axi-cel in this setting is important. We report here the real-world experience of 17 pts treated with axi-cel who had a history of secondary CNS involvement or had active CNS disease at time of CAR T infusion. Methods: Seventeen academic centers from the US Lymphoma CAR T Consortium contributed data independently from the manufacturer. Data regarding secondary CNS involvement, management, and outcome were obtained in addition to CAR T therapy outcome for pts who were identified as having active, secondary CNS involvement at the time of evaluation for CAR-T therapy. Nine centers reported data on 17 cases with CNS involvement. Follow-up data was missing for one pt in the CNS cohort. Lee criteria or the modified Lee grading scale were used for cytokine release syndrome (CRS). CTCAEv4 or CARTOX grading were used for immune effector cells associated neurotoxicity syndrome (ICANS). All leukapheresed pts were included in the intention to treat (ITT) analysis for response rate and event-free survival (EFS). EFS was defined as date of leukapheresis until progression or death due to any cause. EFS was evaluated using Kaplan Meier curves with log-rank test. Differences in clinical characteristics and response between CNS and non-CNS pts were not formally tested due to small sample size and multiple comparison concerns. Results: With a data cut-off of 4/30/2019, 300 pts underwent leukapheresis with intention to manufacture standard of care axi-cel. By the time of leukapheresis, 17 (6%) had secondary CNS involvement (4 parenchymal disease, 10 leptomeningeal/CSF, 3 data not available). Compared to the non-CNS cohort, baseline demographics were comparable (Panel A). Manufactured axi-cel was within specification for 100% of the CNS cohort. There was a higher rate of bridging therapy use in the CNS cohort 82% (1 steroids only, 2 radiation therapy, 12 systemic therapy) vs 52% in non-CNS cohort; p=0.022. Time from leukapheresis to CAR T infusion was 3.5 days longer in the CNS cohort as opposed to the non-CNS cohort: median time of 29.5 (range 20-76) vs. 26 days (range 5-67), (p=0.029), respectively. The CAR T infusion rate was 88% for the CNS cohort (15/17) compared to 93% (262/283) in the non-CNS cohort. Among the 15 infused pts in the CNS cohort, 10 had resolution of CNS involvement, and 5 had persistent active CNS disease at time of CAR T infusion. After axi-cel infusion, the incidence of CRS and ICANS, of any grade or grade 3 or higher, were comparable between the CNS and non-CNS cohorts. Tocilizumab and steroid use were comparable between the two groups (Panel B). No seizures or cerebral edema were noted in the CNS cohort. With a median follow-up of 10.1 months from leukapheresis (range 7.6-12.6), the ITT best overall response rates (CR+PR) and ongoing responses at month 6 between CNS and non-CNS cohorts were 75% vs. 59%, and 41% vs. 31%, respectively (Panel B). In the 5 pts with active CNS disease at time of CAR T infusion, the response of CNS disease were 2 CR, 1 PR and 2 PD as best response. In the 10 pts with resolved CNS disease at time of CAR T infusion, 2 PD were seen and both occurred systemically. EFS from leukapheresis was not statistically significantly different between CNS and non-CNS cohorts (6 months EFS: CNS cohort, 36%; non-CNS cohort 57%. HR=1.58, 95% CI: 0.83-3.01, p=0.16, Panel C). Six month EFS from the date of infusion for the CNS cohort was 49.9% (Panel D). Conclusions: Pts attempting CAR T therapy with secondary CNS disease in the real world setting had similar rates of CAR T infusion, toxicity, and outcomes when compared to patients without CNS disease. Small sample size and limited follow-up caution the strength of conclusions for application to clinical practice, but these results support further investigation of CAR T in pts with history of or active secondary CNS lymphoma. Figure Disclosures Bennani: Seattle Genetics: Other: Advisory board; Adicet Bio: Other: Advisory board; Purdue Pharma: Other: Advisory board; Purdue Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Purdue Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Kite Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Adicet Bio: Other: Advisory board; Adicet Bio: Other: Advisory board; Kite Pharma: Other: Advisory board. Maurer:Celgene: Research Funding; Nanostring: Research Funding; Morphosys: Membership on an entity's Board of Directors or advisory committees. Nastoupil:Bayer: Honoraria; Spectrum: Honoraria; TG Therapeutics: Honoraria, Research Funding; Novartis: Honoraria; Janssen: Honoraria, Research Funding; Gilead: Honoraria; Genentech, Inc.: Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Jain:Kite/Gilead: Consultancy. Chavez:Novartis: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genentech: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees. Cashen:Seattle Genetics: Other: Speaker's Bureau; Novartis: Other: Speaker's Bureau; Celgene: Other: Speaker's Bureau. Reagan:Kite, A Gilead Company: Consultancy; Curis: Consultancy; Seattle Genetics: Research Funding. Oluwole:Pfizer: Consultancy; Spectrum: Consultancy; Gilead Sciences: Consultancy; Bayer: Consultancy. McGuirk:Novartis: Research Funding; Fresenius Biotech: Research Funding; Astellas: Research Funding; Bellicum Pharmaceuticals: Research Funding; Kite Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Gamida Cell: Research Funding; Pluristem Ltd: Research Funding; ArticulateScience LLC: Other: Assistance with manuscript preparation; Juno Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Deol:Novartis: Other: Advisory board; Kite: Other: Advisory board; Agios: Other: Advisory board. Sehgal:Juno/Celgene: Research Funding; Merck: Research Funding; Kite/Gilead: Research Funding. Goy:COTA: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Other: leadership role for profit healthcare company; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Astrazenca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; University of Nebraska: Research Funding; Hakensackumc: Research Funding; Takeda: Other: Grants outside of the submitted work; Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Grants outside of the submitted work; Pharmacyclics/Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Grants outside of the submitted work, Research Funding; Genentech: Other: Grants outside of the submitted work, Research Funding; Hackensack University Medical Center, RCCA: Employment; Acerta: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Grants outside of the submitted work, Research Funding. Hill:Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; TG therapeutics: Research Funding; AstraZeneca: Consultancy, Honoraria; Kite: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Celegene: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Consultancy, Research Funding; Takeda: Research Funding; Amgen: Research Funding. Vu:Celgene: Other: Stock. Andreadis:Genentech: Equity Ownership, Other: Spouse is Employee; Novartis: Honoraria, Research Funding; Amgen: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Gilead: Consultancy; Jazz Pharmaceuticals: Consultancy; Bayer: Consultancy. Munoz:Incyte: Research Funding; Portola: Research Funding; Celgene: Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Speakers Bureau; AstraZeneca: Speakers Bureau; Pharmacyclics LLC an AbbVie Company: Consultancy, Research Funding, Speakers Bureau; Kite Pharma: Consultancy, Research Funding, Speakers Bureau; Gilead: Consultancy, Speakers Bureau; Fosunkite: Speakers Bureau; Kyowa: Consultancy, Honoraria, Speakers Bureau. Vose:Acerta Pharma: Honoraria, Other: Grants, Research Funding; Bristol-Meyers Squibb Company: Research Funding; Celgene Corporation: Research Funding; Incyte Corporation: Research Funding; Kite Pharma: Honoraria, Other: Grants, Research Funding; Novartis: Research Funding; Seattle Genetics: Research Funding; AbbVie: Consultancy, Honoraria; Epizyme: Consultancy, Honoraria; Legend Pharmaceuticals: Honoraria. Miklos:Miltenyi Biotech: Membership on an entity's Board of Directors or advisory committees; Becton Dickinson: Research Funding; AlloGene: Membership on an entity's Board of Directors or advisory committees; Precision Bioscience: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Kite-Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding. Locke:Kite: Other: Scientific Advisor; Novartis: Other: Scientific Advisor; Cellular BioMedicine Group Inc.: Consultancy. Neelapu:Unum Therapeutics: Consultancy, Research Funding; BMS: Research Funding; Pfizer: Consultancy; Incyte: Consultancy; Poseida: Research Funding; Allogene: Consultancy; Merck: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Karus: Research Funding; Precision Biosciences: Consultancy; Cell Medica: Consultancy; Acerta: Research Funding; Cellectis: Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy. Lin:Novartis: Membership on an entity's Board of Directors or advisory committees; Juno: Membership on an entity's Board of Directors or advisory committees; Kite/Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; BlueBird Bio: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sorrento: Membership on an entity's Board of Directors or advisory committees.

MDJ and MTJ contributed equally; FLL and AG contributed equally. Introduction Axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tisa-cel) are autologous anti-CD19 CAR T-cell therapies approved for the treatment of adults with relapsed or refractory large B-cell lymphoma (LBCL) who have failed at least two lines of systemic therapy. In the ZUMA-1 trial that led to axi-cel approval, the median time between apheresis and delivery of CAR T cells to the treating facility was 17 days (Neelapu, Locke et al. NEJM 2018). Bridging therapy, defined as lymphoma therapy given between apheresis and the start of lymphodepleting chemotherapy, was not permitted on ZUMA-1. By contrast, the pivotal JULIET trial for tisa-cel (Schuster et al. NEJM 2019) had a median time from enrollment to infusion of 54 days and 92% of patients received bridging therapy. Whether bridging therapy affects lymphoma CAR T outcomes is unknown. Here we evaluate patients receiving bridging therapy for axi-cel in a large multicenter cohort. Methods and Results The US Lymphoma CAR T Consortium includes seventeen US academic centers that contribute data from lymphoma patients treated with standard of care (SOC) CAR T-cell therapy independently of manufacturers. As of 8/31/2018, 300 patients were apheresed with intent to manufacture SOC axi-cel for LBCL. Of the 23 patients that underwent apheresis for axi-cel and did not receive it, 20 had lymphoma progression or death that precluded CAR T infusion, of which 16 received bridging therapy. In this study, we analyze the modified intent-to-treat (mITT) population of 276 patients receiving CAR T infusion with a median follow up of 9 months. In this group, 146 (53%) patients received bridging therapy while 130 (47%) patients received no bridging therapy. Bridging therapy consisted of steroids alone (n = 35, 24%), chemotherapy (n = 73, 50%), radiation (n = 24, 16%), or targeted therapies (n = 14, 10%). At baseline, a higher proportion of patients in the bridging therapy group had an ECOG score of 2 - 4 vs. 0 - 1 (bridging 24.8%, no bridging 6.1%, p &lt;0.001), IPI score of 3 -5 vs. 0 - 2 (bridging 67.6%, no bridging 34.3%, p &lt;0.001), bulky disease greater than 10 cm (28.2% vs. 13.0%, p = 0.002), immunohistochemical double expression of MYC and BCL2 (42.5% vs. 24.6%, p =0.004) and would not have met all the eligibility criteria for ZUMA-1 for reasons other than bridging therapy (48.6% vs. 30.0%, p = 0.002). After axi-cel infusion, patients in the bridging group had similar rates of severe (grade 3 or higher) cytokine release syndrome (CRS) (8.2% vs. 5.3%, p = 0.34) and ICANS (35.2% vs. 28.2%, p = 0.25). However, the rate of ICU admission was higher in the bridging group (41.4% vs. 22.9%, p = 0.001) as was median length of hospital stay (15 vs. 14 days, p = 0.02). While data on cytopenias was not collected, use of G-CSF after CAR T therapy was higher in the bridging group (48.2% vs. 32.1%, p = 0.006). In terms of outcomes, in multivariate analysis correcting for confounding features, there was no statistically significant difference in overall response rate (p = 0.2), complete response rate (p = 0.19), and progression free survival (p = 0.3) between bridging and no bridging groups; but bridging therapy was associated with significantly poorer overall survival (p = 0.001) and lymphoma specific survival (p = 0.019) (figure 1.). Both death due to lymphoma (33.1% vs. 13.0%) and death due to treatment-related mortality (TRM) (6.9% vs. 1.5%) were higher in the bridging group (p &lt;0.001). Conclusions Lymphoma patients receiving bridging therapy had poorer prognostic factors at baseline and after axi-cel infusion experienced decreased lymphoma-specific and overall survival compared with patients with no bridging. This inferior outcome raises the possibility that bridging therapy may identify a sub-group of lymphoma patients with a different biology, or alternatively, bridging therapy may have an effect on the host or the tumor microenvironment that may impact CAR-T efficacy. With or without bridging, 7% of patients in our series did not receive axi-cel due to lymphoma progression and/or death. In addition, there may have been patients where bridging prevented progression or death prior to axi-cel infusion. Prospective evaluation of different bridging strategies is warranted to determine if any can improve outcomes after axi-cel, and/or if they should be utilized only for patients requiring emergent disease control during the manufacture period. Disclosures Jain: Kite/Gilead: Consultancy. Nastoupil:Bayer: Honoraria; Celgene: Honoraria, Research Funding; Genentech, Inc.: Honoraria, Research Funding; Gilead: Honoraria; Janssen: Honoraria, Research Funding; Novartis: Honoraria; TG Therapeutics: Honoraria, Research Funding; Spectrum: Honoraria. Lin:Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; BlueBird Bio: Research Funding; Kite/Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Sorrento: Membership on an entity's Board of Directors or advisory committees. Lunning:Curis: Research Funding; Janssen Scientific Affairs, LLC: Consultancy, Research Funding; Juno Therapeutics: Consultancy, Research Funding; MiRagen: Research Funding; TG Therapeutics: Consultancy, Research Funding; AbbVie: Consultancy; Bayer: Consultancy; DAVA: Consultancy; Gilead Sciences, Inc.: Consultancy; Kite: Consultancy; Novartis: Consultancy; OncLive: Consultancy; Portola: Consultancy; Seattle Genetics: Consultancy; Spectrum: Consultancy; VANIUM: Consultancy; Verastem: Consultancy. Reagan:Kite, A Gilead Company: Consultancy; Curis: Consultancy; Seattle Genetics: Research Funding. Oluwole:Pfizer: Consultancy; Spectrum: Consultancy; Gilead Sciences: Consultancy; Bayer: Consultancy. McGuirk:Juno Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Fresenius Biotech: Research Funding; Astellas: Research Funding; Bellicum Pharmaceuticals: Research Funding; Kite Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Gamida Cell: Research Funding; Pluristem Ltd: Research Funding; ArticulateScience LLC: Other: Assistance with manuscript preparation. Deol:Novartis: Other: Advisory board; Kite: Other: Advisory board; Agios: Other: Advisory board. Goy:University of Nebraska: Research Funding; Hakensackumc: Research Funding; Astrazenca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Hackensack University Medical Center, RCCA: Employment; Genentech: Other: Grants outside of the submitted work, Research Funding; Acerta: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Grants outside of the submitted work, Research Funding; Pharmacyclics/Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Grants outside of the submitted work, Research Funding; Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Grants outside of the submitted work; Takeda: Other: Grants outside of the submitted work; COTA: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Other: leadership role for profit healthcare company. Hill:Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Kite: Consultancy, Honoraria; Celegene: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria; Takeda: Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Consultancy, Honoraria; Genentech: Consultancy, Research Funding; TG therapeutics: Research Funding; Amgen: Research Funding. Munoz:Kyowa: Consultancy, Honoraria, Speakers Bureau; Seattle Genetics: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene/Juno: Consultancy, Research Funding; Genentech: Consultancy, Research Funding, Speakers Bureau; Kite/Gilead: Consultancy, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Consultancy; Alexion: Consultancy; Pfizer: Consultancy; Fosunkite: Speakers Bureau; AstraZeneca: Speakers Bureau; Portola: Research Funding; Incyte: Research Funding; Pharmacyclics /Janssen: Consultancy, Research Funding, Speakers Bureau; Bayer: Consultancy, Speakers Bureau; Merck: Consultancy. Chavez:Janssen Pharmaceuticals, Inc.: Speakers Bureau; Kite Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Genentech: Speakers Bureau. Vose:Acerta Pharma: Honoraria, Other: Grants, Research Funding; Bristol-Meyers Squibb Company: Research Funding; Celgene Corporation: Research Funding; Incyte Corporation: Research Funding; Kite Pharma: Honoraria, Other: Grants, Research Funding; Novartis: Research Funding; Seattle Genetics: Research Funding; AbbVie: Consultancy, Honoraria; Epizyme: Consultancy, Honoraria; Legend Pharmaceuticals: Honoraria. Miklos:Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Kite-Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; AlloGene: Membership on an entity's Board of Directors or advisory committees; Precision Bioscience: Membership on an entity's Board of Directors or advisory committees; Miltenyi Biotech: Membership on an entity's Board of Directors or advisory committees; Becton Dickinson: Research Funding; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees. Neelapu:Cellectis: Research Funding; Allogene: Consultancy; Incyte: Consultancy; BMS: Research Funding; Novartis: Consultancy; Karus: Research Funding; Celgene: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Merck: Consultancy, Research Funding; Acerta: Research Funding; Poseida: Research Funding; Unum Therapeutics: Consultancy, Research Funding; Pfizer: Consultancy; Precision Biosciences: Consultancy; Cell Medica: Consultancy. Bennani:Kite Pharma: Other: Advisory board; Kite Pharma: Other: Advisory board; Purdue Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Adicet Bio: Other: Advisory board; Adicet Bio: Other: Advisory board; Adicet Bio: Other: Advisory board; Seattle Genetics: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board; Purdue Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Purdue Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board. Andreadis:Pharmacyclics: Research Funding; Novartis: Research Funding; Roche: Equity Ownership; Celgene: Research Funding; Juno: Research Funding; Jazz Pharmaceuticals: Consultancy; Genentech: Consultancy, Employment; Merck: Research Funding; Gilead: Consultancy; Kite: Consultancy. Sehgal:Juno/Celgene: Research Funding; Merck: Research Funding; Kite/Gilead: Research Funding. Locke:Novartis: Other: Scientific Advisor; Kite: Other: Scientific Advisor; Cellular BioMedicine Group Inc.: Consultancy.

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

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