Bennani, N. Nora

e15020 Background: Durable responses were seen in registration trials for CAR-T in NHL across poor prognostic groups including early relapse post stem cell transplant (ASCT). Multi-center reports of real-world practice noted patients who received BT prior to CAR-T had decreased survival. The impact of last ST and response to BT on clinical outcome are examined here. Methods: Retrospective chart review was performed on 47 patients who received axicabtagene ciloleucel from June 2016 – September 2019 at Mayo Clinic, Rochester. ST was defined as last therapy prior to leukapheresis and grouped into categories – non-ASCT (chemotherapy, and immunotherapy), and ASCT. BT was defined as therapy given between leukapheresis and CAR-T. Response to therapy was evaluated using 2014 Lugano criteria. Event free survival (EFS) was defined as time from CAR-T infusion to progression, next treatment, or death. Results: The ST distribution was 77% non-ASCT [chemo 66% (31), and immunotherapy 11% (5)], and 23% (11) ASCT. EFS was significantly prolonged for the ASCT (median not reached) vs non-ASCT (median 3.8 months, p = 0.03) despite no difference in median prior lines of therapy. This may reflect more aggressive disease in the non-ASCT arm, as time from start of ST to leukapheresis was shorter (median non-ASCT 2.2 months vs. ASCT 4.4 months, p = 0.0008). Patients received BT if there were concerns for symptomatic progression during CAR-T manufacturing that would reduce the likelihood to receive CAR-T. Sixty-two percent (29) patients received BT (11 chemo, and 18 immunotherapy). The EFS did not differ between the type of BT. However, patients who progressed after BT had worse EFS than those who achieved stable disease or partial response (median 2.8 vs 8.7 months, p = 0.03). Conclusions: Patients who received CAR-T as the next treatment after ASCT had better EFS than those after other types of ST. While patients who received BT have worse survival than those who didn’t, having some control of lymphoma progression with BT was associated with better EFS than those who continued to have progressive disease.

3028 Background: Chimeric antigen receptor T-cell (CAR-T) therapy induces complete remission (CR) in 30-40% of patients with non-Hodgkin lymphoma (NHL). However, for patients who do not achieve CR as their first response, predictors for achieving CR as best response can guide management between careful observation or early intervention. Increased absolute lymphocyte count to absolute monocyte count ratio (ALC/AMC) predicts better response rates and survival in NHL patients receiving chemotherapy and/or autologous stem cell transplant. We evaluated the prognostic impact of ALC/AMC in CAR-T therapy for NHL. Methods: This was a retrospective review of patients who received CAR-T for NHL from June 2016-August 2019. ALC/AMC was assessed at the start of lymphodepletion (LD) chemotherapy. The receiver operator curve (ROC) was used to determine the best cutoff for ALC/AMC in predicting CR at 3 months. Event-free survival (EFS) was defined from time of CAR-T infusion to relapse or death, whichever occurred first. Overall survival (OS) was defined from time of infusion to death of any cause. Results: Forty-seven patients received axicabtagene ciloleucel, with a median follow-up of 14 months. By ROC, ALC/AMC > 0.8 before LD chemotherapy was predictive of achieving CR at 3 months. Baseline characteristics were similar between the high (n = 30) and low (n = 17) ALC/AMC groups. Patients with an ALC/AMC > 0.8 at the time of LD chemotherapy were more likely to achieve CR at 3 months (46% vs. 12%, p = 0.01), 6 months (52% vs. 0%, p < 0.0005), and 12 months (42% vs. 0%, p = 0.01). Correspondingly, the EFS and OS were significantly shorter in patients with ALC/AMC≤0.8 vs. those > 0.8 (median EFS: 2 vs. 13 months, P < 0.0001) and (median OS: 15 months vs. not reached, P = 0.03), respectively. Association between ALC/AMC ratio and EFS and OS remained consistent in multivariate Cox models after adjusting for other prognostic variables, including abnormal lactate dehydrogenase and increased ferritin level at infusion day. Conclusions: ALC/AMC > 0.8 before lymphodepletion chemotherapy is a strong predictor for complete remission as well as improved event-free and overall survival for axicabtagene ciloleucel in NHL.

PURPOSE Axicabtagene ciloleucel (axi-cel) is an autologous CD19-directed chimeric antigen receptor (CAR) T-cell therapy approved for relapsed/refractory large B-cell lymphoma (LBCL) on the basis of the single-arm phase II ZUMA-1 trial, which showed best overall and complete response rates in infused patients of 83% and 58%, respectively. We report clinical outcomes with axi-cel in the standard-of-care (SOC) setting for the approved indication. PATIENTS AND METHODS Data were collected retrospectively from all patients with relapsed/refractory LBCL who underwent leukapheresis as of September 30, 2018, at 17 US institutions with the intent to receive SOC axi-cel. Toxicities were graded and managed according to each institution’s guidelines. Responses were assessed as per Lugano 2014 classification. RESULTS Of 298 patients who underwent leukapheresis, 275 (92%) received axi-cel therapy. Compared with the registrational ZUMA-1 trial, 129 patients (43%) in this SOC study would not have met ZUMA-1 eligibility criteria because of comorbidities at the time of leukapheresis. Among the axi-cel–treated patients, grade ≥ 3 cytokine release syndrome and neurotoxicity occurred in 7% and 31%, respectively. Nonrelapse mortality was 4.4%. Best overall and complete response rates in infused patients were 82% (95% CI, 77% to 86%) and 64% (95% CI, 58% to 69%), respectively. At a median follow-up of 12.9 months from the time of CAR T-cell infusion, median progression-free survival was 8.3 months (95% CI, 6.0 to15.1 months), and median overall survival was not reached. Patients with poor Eastern Cooperative Oncology Group performance status of 2-4 and elevated lactate dehydrogenase had shorter progression-free and overall survival on univariable and multivariable analysis. CONCLUSION The safety and efficacy of axi-cel in the SOC setting in patients with relapsed/refractory LBCL was comparable to the registrational ZUMA-1 trial.

Introduction: With the expanding use of CAR-T cell therapy, which is associated with serious adverse effects (AEs), there is a need to characterize the patient's experience over time to guide patient/provider education, and help optimize symptom management. This study reports on longitudinal evaluation of patient-reported quality of life (QOL) and symptom burden of CAR-T cell therapy compared with established forms of cellular therapy i.e autologous stem cell transplant (autoSCT) and allogeneic SCT (alloSCT). Methods: Patients with hematologic malignancies were prospectively recruited in three cohorts: CAR-T, autoSCT and alloSCT. The primary endpoint was change in QOL from baseline, using the FACT-G questionnaire. Secondary endpoints were patient-reported AEs (PRO-AEs) using 7 items from the PRO-CTCAE and assessment of cognition/memory using the NeuroQOLv2 questionnaire. PRO-CTCAE data was graded using a composite score (combining frequency, severity, and interference) and rates, using a method adjusting for pre-existing baseline symptoms, were compared using Fisher's exact test. We also evaluated the time profile of PRO-AEs using the Toxicity over Time (ToxT) approach, a longitudinal approach to AE analysis (Thanarajasingam Lancet Onc 2016). Patients completed questionnaires at baseline, week 2 and monthly thereafter. Results: From 07/2018 to 06/2019, 93 patients were recruited (CAR-T: 20; autoSCT: 37; alloSCT: 36). At data cut-off, week 2 and months 1, 2 and 3 data were available in 74, 62, 46 and 35 patients, respectively. There was no difference in patient age across the 3 groups (median age 63, range 23-77; p=0.26). Baseline QOL by FACT-G total score (mean=83.4, SD=14.7; p=0.77), side effect bother by FACT-G GP5 (66/93 [71%] a little bit or less; p=0.72), activities and function (70/93 [75%] fairly normal activities or no limitations; p=0.68) and cognition by NeuroQOL t-score (mean=52.2, SD=8.13; p=0.39) were similar across 3 groups at baseline. The CAR-T group experienced significantly less worsening in QOL (FACT-G) than both autoSCT and alloSCT groups (Fig. 1a). Worsening in overall QOL nadired at week 2, after which QOL gradually returned to baseline in all groups. When comparing changes from baseline in overall QOL, statistically significant differences between groups were evident at week 2 (CAR-T vs autoSCT p&lt;0.001; vs alloSCT p&lt;0.001), month 1 (CAR-T vs autoSCT p=0.02; vs alloSCT p=0.003), month 2 (CAR-T vs autoSCT p=0.02; vs alloSCT p=0.001) and month 3 (CAR-T vs autoSCT p=NS; vs alloSCT p=0.03). Results for physical (Fig. 1b) and functional well-being (WB) were similar, with significantly less QOL worsening at week 2 in CAR-T vs autoSCT and alloSCT groups. The most common PRO-AEs (Table 1) in the CAR-T group were decreased appetite (59%), diarrhea (53%) and fatigue (44%). There was no statistically significant difference in the PRO-AEs between CAR-T and autoSCT groups. However, patients undergoing alloSCT had significantly higher proportion of PRO-AEs vs the CAR-T group, except for neuropathy and sad feelings. AutoSCT and alloSCT groups had significant worsening of FACT-G side effect bother (GP5) at week 2, which was significantly different from that of the CAR-T group, following which the side effect bother gradually returned to baseline. (Fig. 1c) This was the first application of ToxT to PRO-CTCAE data (graphs not shown). Bar charts of maximum grade frequency and stream plots of mean grade over time demonstrate that mouth sores, fatigue, diarrhea and decreased appetite peak at week 2 and improve by month 3, and are of lesser severity in the CAR-T vs autoSCT and alloSCT groups. The trajectory of maximum grade across all PRO-AEs was similar by group as overall side effect burden by FACT-G GP5. Heatmap visualization demonstrated significant intra-patient variability and allowed inspection of data completeness. No difference in cognition and memory was observed across the three groups over the first three months. (Fig. 1d) Conclusion: This study is the first to our knowledge to provide comprehensive PRO data comparing QOL, patient-reported AEs and cognition in CAR-T cell therapy vs. auto- and alloSCT, and the first application of ToxT to PRO-CTCAE data. Short-term QOL, including physical and functional WB domains was better in the CAR-T group vs. SCT groups. These data can serve as a guide for patient education and symptom management in CAR-T cell therapy. Co-senior authors: SKK & ACD Disclosures Paludo: Celgene: Research Funding; Celgene: Research Funding; Verily Life Sciences: Research Funding; Verily Life Sciences: Research Funding. Gertz:Johnson and Johnson: Speakers Bureau; Celgene: Consultancy; Appellis: Consultancy; Amyloidosis Foundation: Research Funding; DAVA oncology: Speakers Bureau; Physicians Education Resource: Consultancy; Amgen: Consultancy; Janssen: Consultancy; Abbvie: Other: personal fees for Data Safety Monitoring board; Medscape: Consultancy, Speakers Bureau; Prothena Biosciences Inc: Consultancy; Teva: Speakers Bureau; Research to Practice: Consultancy; Annexon: Consultancy; Alnylam: Consultancy; International Waldenstrom Foundation: Research Funding; Ionis/Akcea: Consultancy; Spectrum: Consultancy, Research Funding; i3Health: Other: Development of educational programs and materials; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Proclara: Membership on an entity's Board of Directors or advisory committees; Springer Publishing: Patents & Royalties. Dispenzieri:Akcea: Consultancy; Intellia: Consultancy; Janssen: Consultancy; Pfizer: Research Funding; Takeda: Research Funding; Celgene: Research Funding; Alnylam: Research Funding. Ansell:Trillium: Research Funding; LAM Therapeutics: Research Funding; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Trillium: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Regeneron: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; Affimed: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Affimed: Research Funding; Seattle Genetics: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding. Bennani:Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Adicet Bio: Other: Advisory board; Adicet Bio: Other: Advisory board; Purdue Pharma: Other: Advisory board; Purdue Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Seattle Genetics: Other: Advisory board; Seattle Genetics: Other: Advisory board; Kite Pharma: Other: Advisory board; Adicet Bio: Other: Advisory board; Kite Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board; Purdue Pharma: Other: Advisory board. Kumar:Takeda: Research Funding; Celgene: Consultancy, Research Funding; Janssen: 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.

Introduction: Peripheral T-cell lymphomas (PTCL) are a heterogeneous group of mature aggressive T-cell non-Hodgkin lymphomas. They carry a worse prognosis for most subtypes compared with their B-cell counterparts. Despite the recent approval of newer therapies, the response rate and duration of clinical benefit is short and the outlook for patients with relapsed/refractory (RR) PTCL remains poor. There is therefore a need for novel effective therapies in PTCL. Targeting the profoundly immunosuppressive tumor microenvironment (TME) in PTCL is one such approach. Preclinical data show that malignant cells in PTCL overexpress programmed death ligand 1 (PD-L1), which signals via programmed death-1 (PD-1) receptor, and provides an inhibitory signal further suppressing antitumor immunity. PD-1/PD-L1/2 interactions in PTCL are particularly complicated as both the receptor and ligands can be expressed on the malignant T-cell. While the use of anti-PD-1 blocking antibodies has shown remarkable efficacy particularly in relapsed Hodgkin lymphoma, only a small number of patients with PTCL have been treated with checkpoint blockade. We conducted an investigator-initiated phase 2 prospective study of single-agent nivolumab for RR PTCL. We report here the results of the prespecified interim analysis. Study design and patient selection: Nivolumab was given at a flat dose of 240 mg intravenously (IV) every 2 weeks for 8 cycles then 480 mg IV every 4 weeks starting cycle 9. The primary objective was to assess the overall response rate (ORR) defined as proportion of subjects achieving either a partial response (PR) or complete response (CR) within 12 cycles of treatment. Secondary objectives were to assess safety and tolerability of nivolumab in PTCL and to assess progression-free survival (PFS), duration of response (DOR) and overall survival (OS). Pre-planned sample size was 39, assuming that an ORR of 10% or less would be considered negative and an ORR of 30% or greater would warrant further study. We used a one-stage design with an interim analysis (upon enrolling 12 subjects) based on a Simon optimal design to assess efficacy. This design had a 90% power with a 1-sided 10% level test. The Duffy and Santner method was utilized to determine confidence intervals for the ORR. Kaplan-Meier methods were used to assess PFS, OS, and DOR. This study was sponsored by Bristol-Myers Squibb (NCT03075553). Results: Twelve patients who received at least one cycle of nivolumab were included in this interim analysis. Patient characteristics are illustrated in table 1. Half (6/12) of the patients had angioimmunoblastic T-cell lymphoma (AITL), 3/12 had PTCL, not otherwise specified (NOS), one had ALK negative anaplastic large cell lymphoma (ALK- ALCL). Most (11/12) were advanced stage (stage 4), had extranodal disease and half of the patients had received a prior autologous transplant. The ORR was 33% (4/12) (95% CI: 12.3 - 63.7%): 1 CR seen in ALK-ALCL; 2 PR, 1 in PTCL, NOS and 1 in enteropathy associated T-cell lymphoma; 1 CR in AITL. The median DOR was 3.6 months (95% CI: 1.9-6.9). The median PFS for all 12 patients was short at 1.9 months (95% CI: 1.5-8.7); median OS was 7.9 months (95% CI: 3.4-10.8) (Panel A). Hyperprogressive disease (defined as dramatic progression within 1 cycle of treatment) occurred in 4 patients. Observed grade 3 and higher adverse events (AEs) were as follows: non-hematologic AEs in 5/12 (41.7%), while hematologic AEs were seen in 3/12 (25%) patients. Conclusions: Nivolumab had modest clinical activity in patients with R/R PTCL and the study met the criteria at interim analysis to continue accrual. However, due to the high number of patients with hyperprogressive disease, the moderate activity of the drug, and short DOR, a decision was made to halt the study. These findings likely reflect the distinct biology of PTCL and should be considered when designing future studies using checkpoint inhibitors in these diseases. Further studies are indicated using nivolumab in combination (rather than a single-agent) and use of biomarkers to better predict the responders. Disclosures Bennani: Purdue Pharma: Other: Advisory board; Adicet Bio: Other: Advisory board; Seattle Genetics: Other: Advisory board; Adicet Bio: Other: Advisory board; Purdue Pharma: Other: Advisory board; Adicet Bio: Other: Advisory board; Seattle Genetics: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board; Purdue Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board. Nowakowski:Selvita: Membership on an entity's Board of Directors or advisory committees; NanoString: Research Funding; Celgene: Consultancy, Research Funding; Bayer: Consultancy, Research Funding; Curis: Research Funding; F. Hoffmann-La Roche Ltd: Research Funding; Genentech, Inc.: Research Funding; MorphoSys: Consultancy, Research Funding. Ansell:Merck: Other: research funding for clinical trials; Seattle Genetics: Other: research funding for clinical trials; Takeda: Other: research funding for clinical trials; Bristol Myers Squibb: Other: research funding for clinical trials; Regeneron: Other: research funding for clinical trials; Affimed: Other: research funding for clinical trials; Pfizer: Other: research funding for clinical trials; AI Therapeutics: Other: research funding for clinical trials.

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.

AbstractHistological transformation in Waldenström macroglobulinemia (WM) is an uncommon complication, with limited data, particularly regarding the impact of MYD88 L265P mutation on transformation. We examined risk factors and outcomes associated with transformation in WM, highlighting the role of MYD88 L265P mutation. Patients with WM seen at Mayo Clinic, Rochester, USA and University Hospital of Reims, France, between 01/01/1996 and December 31, 2017 were included; 50 (4.3%) of 1147 patients transformed to a high‐grade lymphoma, with median time‐to‐transformation of 4.5 (range 0‐21) years in the transformed cohort. The MYD88 L265P mutation status was known in 435/1147 (38%) patients (406 with non‐transformed WM and 29 patients in transformed cohort). On multivariate analysis, MYD88 WT status alone was an independent predictor of transformation (odds ratio, 7[95%CI: 2.1‐23]; P = .003). Additionally, the MYD88 WT status was independently associated with shorter time‐to‐transformation (HR 7.9 [95%CI: 2.3‐27; P = .001]), with a 5‐year transformation rate of 16% for MYD88 WT vs 2.8% with MYD88 L265P mutated patients. Patients with transformation demonstrated a significant increase in risk of death compared to patients who did not transform (HR 5.075; 95%CI: 3.8‐6.8; P < .001). In conclusion, the MYD88 WT status is an independent predictor of transformation and associated with a shorter time‐to‐transformation. Additionally, transformation conferred an inferior overall survival in patients with WM.

M.T.J. and M.D.J. contributed equally; A.G. and F.L.L. contributed equally. Introduction Axicabtagene ciloleucel (axi-cel) is an autologous anti-CD19 CAR T-cell therapy that is approved for the treatment of adults with relapsed or refractory large B-cell lymphoma (LBCL) who have failed at least two prior systemic lines of therapy. In the ZUMA-1 trial that led to axi-cel approval, 93% of patients developed cytokine release syndrome (CRS) (Neelapu, Locke et al. NEJM 2018). CRS is a non-antigen-specific toxicity that occurs as a result of CAR T and bystander immune cell activation. Whether lack of development of CRS after treatment with axi-cel is associated with inferior lymphoma outcomes is unknown. Here we evaluate the outcomes of patients that did not develop CRS after receiving axi-cel in a large multicenter cohort. Methods and Results The US Lymphoma CAR T Consortium includes seventeen US academic centers that contribute data independently of manufacturers. As of 8/31/2018, 300 patients were apheresed with intent to manufacture standard of care axi-cel for LBCL. In this study, we analyzed 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, 25 patients (9%) did not develop CRS and 251 patients (91%) developed CRS following axi-cel infusion. CRS was graded according to Lee criteria (Lee et al. Blood 2014) or CARTOX (Neelapu SS et al. Nat Rev Clin Oncol. 2018). At baseline, a higher proportion of patients in the no CRS group had ECOG score of 0-1 (no CRS group 100% vs. CRS group 82%, p= 0.019) and IPI score of 0-2 (no CRS group 72% vs. CRS group 46%, p = 0.019) After CAR T cell infusion, patients who did not develop CRS had a lower chance of developing grade 3 or higher neurotoxicity (no CRS group 4% vs. CRS group 35%, p=0.001), lower rates of ICU admission (no CRS group 8% vs. CRS group 35%, p = 0.006), and shorter length of hospital stay (median 10 days for no CRS group vs 14 days for CRS group, p &lt; 0.001). Of the 25 patients who had grade 0 CRS, 23 (92%%) also had grade 0 neurotoxicity. In univariate analysis, no CRS was associated with lower complete response (CR) rate (no CRS group 40% vs. CRS group 66%, p=0.015) but no statistically significant difference in overall response rate (ORR) (no CRS group 72% vs. CRS group 84%, p= 0.158). In relation to CRS there was no difference in treatment related mortality among the two groups (CRS group 4% vs. no CRS group 4.4%, p = 0.85). In multivariate analysis correcting for confounding features, no CRS was associated with statistically significant lower complete response rate (p = 0.002), but there was no significant difference in ORR (p = 0.13), overall survival (P=0.15), progression free survival (P=0.16), and time to progression (P= 0.14) between the two groups (figure 1.). Conclusions In this large cohort of LBCL patients receiving axi-cel with median follow up of 9 months, patients that did not develop CRS, compared with those that developed CRS, achieved lower rates of complete response but there was no difference in overall response rate, progression free survival, time to progression, overall survival, and treatment related mortality between the two groups. Disclosures Jain: Kite/Gilead: Consultancy. Nastoupil:Bayer: Honoraria; TG Therapeutics: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Genentech, Inc.: Honoraria, Research Funding; Gilead: Honoraria; Janssen: Honoraria, Research Funding; Novartis: Honoraria; Spectrum: Honoraria. 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. 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; 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; Bellicum Pharmaceuticals: Research Funding; Fresenius Biotech: Research Funding; Astellas: Research Funding. Deol:Agios: Other: Advisory board; Novartis: Other: Advisory board; Kite: Other: Advisory board. Sehgal:Juno/Celgene: Research Funding; Merck: Research Funding; Kite/Gilead: Research Funding. Goy:Acerta: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Grants outside of the submitted work, Research Funding; University of Nebraska: 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; Hakensackumc: Research Funding; Hackensack University Medical Center, RCCA: Employment; 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; 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. Hill:Kite: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Takeda: Research Funding; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celegene: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Research Funding; TG therapeutics: Research Funding; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Research Funding. Andreadis:Juno: Research Funding; Celgene: Research Funding; Novartis: Research Funding; Roche: Equity Ownership; Jazz Pharmaceuticals: Consultancy; Kite: Consultancy; Gilead: Consultancy; Genentech: Consultancy, Employment; Pharmacyclics: Research Funding; Merck: Research Funding. Munoz:Incyte: Research Funding; Portola: Research Funding; AstraZeneca: Speakers Bureau; Fosunkite: Speakers Bureau; Pfizer: Consultancy; Alexion: Consultancy; Bristol-Myers Squibb: Consultancy; Pharmacyclics /Janssen: Consultancy, Research Funding, Speakers Bureau; Bayer: Consultancy, Speakers Bureau; Merck: Consultancy; 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. Chavez:Janssen Pharmaceuticals, Inc.: Speakers Bureau; Genentech: 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. Bennani:Purdue Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Purdue Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Seattle Genetics: Other: Advisory board; Adicet Bio: Other: Advisory board; Adicet Bio: Other: Advisory board; Adicet Bio: Other: Advisory board; Kite Pharma: Other: Advisory board; Kite Pharma: Other: Advisory board; Kite Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Purdue Pharma: Other: Advisory board. 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:Becton Dickinson: Research Funding; Miltenyi Biotech: Membership on an entity's Board of Directors or advisory committees; 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; 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; 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; Juno: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Neelapu:Poseida: Research Funding; Cellectis: Research Funding; Precision Biosciences: Consultancy; Cell Medica: Consultancy; Novartis: Consultancy; Incyte: Consultancy; Celgene: Consultancy, Research Funding; Allogene: Consultancy; Acerta: Research Funding; Unum Therapeutics: Consultancy, Research Funding; Pfizer: Consultancy; Kite, a Gilead Company: Consultancy, Research Funding; BMS: Research Funding; Merck: Consultancy, Research Funding; Karus: Research Funding. Ghobadi:Wugen: Consultancy; Celgene: Consultancy; EUSA: Consultancy; Kite Pharma a Gilead Company: Consultancy, Research Funding, Speakers Bureau. Locke:Novartis: Other: Scientific Advisor; Cellular BioMedicine Group Inc.: Consultancy; Kite: Other: Scientific Advisor.

Background Burkitt NHL (BL) is a rare hematologic malignancy that occurs in younger adults and is highly curable with aggressive chemoimmunotherapy induction regimens. Unfortunately, patients that are refractory or relapse after these regimens fare poorly and treatment guidelines are not well established. The typical approach is with standard platinum-based salvage regimens; those who obtain a complete remission (CR) become eligible for autologous or allogeneic stem cell transplantation (SCT). Chimeric antigen receptor T (CAR-T) cell therapy and bispecific antibodies offer potential novel approaches for these patients, especially those who are unable to achieve remission in order to proceed with SCT; however, CAR-T therapy is not approved nor even tested in BL other than promising single case reports (Avigdor A, Bone Marrow Transplant. 2018 May 24). The goal of this study was to learn the clinical features and outcome of R/R BL in order to design a prospective strategy for novel therapy use in relapsed/refractory (R/R) BL patients. Methods We reviewed the Mayo Clinic Lymphoma database to find cases of BL diagnosed and treated between 1/1/2000 - 9/30/2018. Forty-two cases were identified and 32 (76%) entered CR and never relapsed; 10 (24%) did not respond or relapsed and are the focus of this report. Demographic, clinical response to treatment regimens, and long-term outcomes were extracted from the Mayo Clinic electronic medical record. Results The 10 patients with R/R BL had a median age of 41 years (range, 28-59); all had received aggressive chemoimmunotherapy induction regimens; 7 were primary refractory and 3 relapsed within 3 months (2-4) of achieving first CR. All 3 patients that relapsed did so in the central nervous system (CNS) despite receiving CNS prophylaxis with their induction therapy regimen. The response to salvage therapy was 30% (3/10) with 10% CR and 30% (3/10) proceeded to autologous SCT (no patients made it to allogenic SCT). The median progression free survival (PFS) and overall survival (OS) from diagnosis of all 10 patients was 4 months (1-9) and 70% (7/10) died within 6±4 months from date of relapse. The 3 patients with relapsed BL survived 7, 10, and17 months from date of relapse. The 3 patients who did survive to receive a SCT lived 2, 4, and 13 months from date of SCT. None of the 10 patients survived past 26 months from date of diagnosis. Conclusions Patients with R/R BL represent an uncommon and unique subset of aggressive NHL that require a new therapeutic approach such as CAR-T. Our study demonstrates the very poor outcome with traditional salvage therapies and the very short OS of these young, otherwise healthy patients. We recommend that these patients be considered as emergencies and referred promptly for novel therapies such as CAR-T trials at the very first sign of treatment failure. Waiting with the intent of attaining response to traditional therapies is futile. Insurance approval initiation and harvesting of T-cells should be rapidly performed, preferably prior to initiating salvage therapy, given the rapid clinical deterioration and demise of these patients. Disclosures Kenderian: Lentigen: Research Funding; Novartis: Patents & Royalties, Research Funding; Tolero: Research Funding; Humanigen: Other: Scientific advisory board , Patents & Royalties, Research Funding; Morphosys: Research Funding; Kite/Gilead: Research Funding. Bennani:Kite Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Adicet Bio: Other: Advisory board; Adicet Bio: Other: Advisory board; Seattle Genetics: Other: Advisory board; Purdue Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Purdue Pharma: Other: Advisory board; Purdue Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Adicet Bio: Other: Advisory board; Kite Pharma: Other: Advisory board; Kite Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Bristol-Myers Squibb: Research Funding. Nowakowski:Selvita: Membership on an entity's Board of Directors or advisory committees; NanoString: Research Funding; MorphoSys: Consultancy, Research Funding; Genentech, Inc.: Research Funding; F. Hoffmann-La Roche Ltd: Research Funding; Curis: Research Funding; Bayer: Consultancy, Research Funding; Celgene: Consultancy, Research Funding.