Bachanová, Veronika

7515 Background: Primary refractory disease (PRD) and early relapse (ER) are predictors of poor prognosis in classic Hodgkin lymphoma (cHL). In this multicenter retrospective study, we describe outcomes of PRD and ER in pts with relapsed/refractory (R/R) cHL treated with salvage therapy (ST) and autologous stem cell transplant (ASCT). Methods: Of 14 sites, adult patients with R/R cHL who received ST and underwent ASCT were enrolled. PRD was defined as progression on frontline chemoimmunotherapy or within 6 months of diagnosis. ER was defined as relapse from 6 months-1 yr of diagnosis. Pts who relapsed >1 yr of diagnosis were called late relapses (LR). Study objectives were Overall response rates (ORR), CR rates, PFS, and OS. Results: Of 986 total pts, 160 had PRD, 365 had ER and 461 had LR. Significantly higher number of pts with PRD, but not ER, had bulky disease (41% vs 27%, p<0.01) and B symptoms (53% vs 38%, p<0.001) than LR. Higher proportions of pts with PRD and ER required >1 line of ST (44% vs 30% vs 23%, p<0.001) before ASCT and received BV maintenance (25% vs 24% vs 16%, p<0.05). When adjusted for B symptoms and Bulky disease, PRD and ER had significantly lower ORR (65% vs 76% vs 84%, p<0.001) and CR (37% vs 46% vs 57%, p<0.001) to first ST than LR. Pts with PRD and ER had significantly lower PFS (56.3%, 61.4%, vs 77.6%, p<.0001) and OS (93% vs 89% vs 94%, p=0.01) than LR. In pts with ER, Brentuximab/bendamustine (BBV) and brentuximab vedotin/nivolumab (BV/nivo) had a trend towards higher ORR (92% vs 92% vs 75%) but significantly higher CR (79.2% vs 76% vs 42%, p<0.01) than platinum based chemotherapy (PBC). In pts with PRD, BBV and BV/Nivo had a statistically insignificant trend towards higher ORR and CR than PBC. The table shows 2 yr PFS by type of ST in PRD, ER, LR. There was no difference in PFS by time to relapse in BV/nivo, CPI and miscellaneous agents. BV/Nivo had a significantly higher PFS than PBC in PRD (88% vs 48%, p<0.05) and ER (95% vs 57%, p<0.05). There was no difference in PFS of PBC and other ST in PRD, ER or LR. OS was not significantly associated with type of ST in either group. Conclusions: PRD and ER are associated with lower response to ST and survival after ASCT compared to late relapse. In pts with PRD and ER, BV/Nivo has high ORR and CR and leads to significantly higher PFS comparable to pts with late relapse and may be preferable ST regardless of time to relapse. [Table: see text]

Abstract Background: Pts with LBCL primary refractory to or relapsed ≤ 12 mo after first-line (1L) therapy may have poor outcomes with SOC, including salvage CT and ASCT, which underscores a critical unmet need. Liso-cel is an autologous CD19-directed, defined composition, 4-1BB CAR T cell product administered at equal target doses of CD8 + and CD4 + CAR + T cells. In the TRANSCEND NHL 001 study (NCT02631044) in pts with R/R LBCL (≥ 2 prior lines of therapy), liso-cel treatment resulted in an ORR of 73% (CR rate, 53%), 2% grade ≥ 3 cytokine release syndrome (CRS), and 10% grade ≥ 3 neurological events (NE) (Abramson et al. Lancet 2020). Here we present a prespecified interim analysis of TRANSFORM (NCT03575351; SOC vs liso-cel as 2L therapy in pts with R/R LBCL). Methods: TRANSFORM is a pivotal, global, randomized, multicenter, phase 3 study comparing efficacy and safety of SOC (Arm A; R-DHAP, R-ICE, or R-GDP per investigator choice followed by BEAM + ASCT) vs liso-cel (Arm B). Pts were adults (aged ≤ 75 years), eligible for ASCT, and with LBCL primary refractory to or relapsed ≤ 12 mo after 1L therapy. Key inclusion criteria were ECOG PS ≤ 1 and adequate organ function (LVEF ≥ 40%; serum CrCl &gt; 45 mL/min); pts with secondary CNS lymphoma were allowed. Key exclusion criteria were prior gene or anti-CD19-targeted therapy, and active infection. Pts in Arm A were to receive 3 cycles of CT. Responding pts (CR or PR) were to proceed to BEAM + ASCT. Pts in Arm B were to undergo lymphodepletion with fludarabine/cyclophosphamide followed by liso-cel at a target dose of 100 × 10 6 CAR + T cells. Bridging therapy with an Arm A CT regimen was allowed. Crossover to receive liso-cel was allowed in Arm A for pts not achieving CR or PR after 3 cycles of CT or not in CR after ASCT, or demonstrating PD at any time. Primary endpoint is event-free survival (EFS) based on independent review committee per Lugano 2014 criteria, defined as time from randomization to death from any cause, PD, failure to achieve CR or PR by 9 weeks after randomization, or start of new antineoplastic therapy, whichever occurred first. Key secondary endpoints included in the testing strategy are CR rate, PFS, and OS. P value significance threshold for endpoints to reject the null hypothesis was ≤ 0.012. Results: A total of 184 pts were randomized, with 92 pts in each arm. Baseline characteristics were well balanced between both arms (Table). Of 91 treated pts in Arm A (1 pt withdrew consent), 43 received BEAM + ASCT, of which 28 achieved CR with CT. Fifty pts crossed over to receive liso-cel. In Arm B, 90 pts received liso-cel infusion; 58 pts (63%) received bridging therapy. Two Arm B pts were not infused (1 each due to manufacturing failure and rapid progression). Median EFS and PFS were significantly longer, and CR rate was significantly improved for Arm B vs Arm A. For Arms A and B, respectively, median EFS was 2.3 vs 10.1 mo (HR, 0.349; P &lt; 0.0001), median PFS was 5.7 vs 14.8 mo (HR, 0.406; P = 0.0001), and CR rate was 39% vs 66% (P &lt; 0.0001). OS data were immature at the time of this analysis with a median follow-up of 6.2 mo (range, 0.9-20.0), but a numerical trend favored Arm B (HR, 0.509; 95% CI, 0.258-1.004; P = 0.0257). Cellular kinetics in Arm B showed a median t max of 10 d (range, 6‒22). No new liso-cel safety signals were detected in the 2L setting. In Arm B, any-grade CRS was reported in 49% of pts, with grade 1 in 37% and grade 2 in 11%. Only 1 pt had grade 3 CRS (onset at Day 9, which resolved in 2 days). Any-grade NEs were reported in 12% of pts and were also primarily low grade (grade 3, 4%). No grade 4 or 5 CRS or NEs were reported. In Arm B, 24% of pts received tocilizumab, 17% received corticosteroids, and none received vasopressors. The most common TEAEs in both arms were cytopenias. Prolonged cytopenias in Arm B (ie, grade ≥ 3 at 35 d after infusion) were reported in 43% of pts; the majority recovered within 2 mo after infusion. Conclusions: In the TRANSFORM study, liso-cel demonstrated statistically significant and clinically meaningful improvement in the primary endpoint, EFS, as well as in key secondary efficacy endpoints (CR rate and PFS) compared with SOC as 2L therapy in pts with LBCL primary refractory to or relapsed ≤ 12 mo after 1L therapy. Safety results in the 2L setting were consistent with the liso-cel safety profile in 3L or later LBCL, and no new safety concerns were identified. Liso-cel improved outcomes vs SOC and exhibited a favorable safety profile, providing support for liso-cel as a potential new SOC for 2L treatment in pts with R/R LBCL. Figure 1 Figure 1. Disclosures Kamdar: SeaGen: Speakers Bureau; ADC Therapeutics: Consultancy; Celgene: Other; TG Therapeutics: Research Funding; KaryoPharm: Consultancy; Celgene (BMS): Consultancy; Genetech: Other; Genentech: Research Funding; Adaptive Biotechnologies: Consultancy; AbbVie: Consultancy; Kite: Consultancy; AstraZeneca: Consultancy. Arnason: Juno/BMS: Honoraria. Glass: BMS: Consultancy; Roche: Consultancy, Research Funding, Speakers Bureau; Riemser: Research Funding; Kite: Consultancy; Novartis: Consultancy; Helios Klinik Berlin-Buch: Current Employment. Bachanova: KaryoPharma: Membership on an entity's Board of Directors or advisory committees; Incyte: Research Funding; FATE: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gamida Cell: Membership on an entity's Board of Directors or advisory committees, Research Funding. Ibrahimi: Karyopharm Theraputics: Divested equity in a private or publicly-traded company in the past 24 months. Mielke: Immunicum: Other: Data safety monitoring board; Novartis: Speakers Bureau; Miltenyi: Other: Data safety monitoring board; DNA Prime SA: Speakers Bureau; Gilead/KITE: Other: Travel support, Expert panel ; Celgene/BMS: Speakers Bureau. Mutsaers: BMS: Consultancy; AstraZeneca: Research Funding. Hernandez-Ilizaliturri: Kite: Other: Advisory Boards; Amgen: Other: Advisory Boards; Pharmacyclics: Other: Advisory Boards; BMS: Other: Advisory Boards; Celgene: Other: Advisory Boards; Incyte: Other: Advisory Boards; AbbVie: Other: Advisory Boards; Gilead: Other: Advisory Boards; Epyzime: Other: Advisory Boards. Izutsu: Novartis: Honoraria, Research Funding; MSD: Research Funding; Kyowa Kirin: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Incyte: Research Funding; Huya Biosciences: Research Funding; Genmab: Honoraria, Research Funding; Fuji Film Toyama Chemical: Honoraria; Eisai: Honoraria, Research Funding; Daiichi Sankyo: Honoraria, Research Funding; Chugai: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Beigene: Research Funding; Bayer: Research Funding; AstraZeneca: Honoraria, Research Funding; Allergan Japan: Honoraria; AbbVie: Honoraria; Ono Pharmaceutical: Honoraria, Research Funding; Pfizer: Research Funding; Solasia: Research Funding; Symbio: Honoraria; Takeda: Honoraria, Research Funding; Yakult: Research Funding. Morschhauser: Celgene: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; Genentech, Inc.: Consultancy; Janssen: Honoraria; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Epizyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Speakers Bureau; Chugai: Honoraria; Servier: Consultancy; AstraZenenca: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Genmab: Membership on an entity's Board of Directors or advisory committees; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees. Lunning: Karyopharm: Consultancy; AstraZeneca: Consultancy; Legend: Consultancy; Verastem: Consultancy; Janssen: Consultancy; Myeloid Therapeutics: Consultancy; Daiichi-Sankyo: Consultancy; Novartis: Consultancy; Spectrum: Consultancy; Celgene, a Bristol Myers Squibb Co.: Consultancy; AbbVie: Consultancy; Acrotech: Consultancy; Beigene: Consultancy; ADC Therapeutics: Consultancy; TG Therapeutics: Consultancy; Morphosys: Consultancy; Kite, a Gilead Company: Consultancy; Kyowa Kirin: Consultancy. Maloney: Amgen: Honoraria; Celgene: Honoraria, Other: Rights to royalties from Fred Hutchinson Cancer Research Center for patents licensed to Juno Therapeutics/Bristol Myers Squibb; A2 Biotherapeutics: Honoraria, Other: Stock options; BMS: Honoraria, Other: Rights to royalties from Fred Hutchinson Cancer Research Center for patents licensed to Juno Therapeutics/Bristol Myers Squibb; Celgene: Other: Research funding was paid to my institution, Research Funding; Umoja: Honoraria; Janssen: Honoraria; Legend Biotech: Honoraria; Genentech: Honoraria; Novartis: Honoraria; MorphoSys: Honoraria; Juno therapeutics: Other: Research funding was paid to my institution, Research Funding; Navan Technologies: Honoraria, Other: Stock options; Kite Pharma: Honoraria, Other: Research funding was paid to my institution, Research Funding; Juno Therapeutics: Honoraria, Other: Rights to royalties from Fred Hutchinson Cancer Research Center for patents licensed to Juno Therapeutics/Bristol Myers Squibb. Crotta: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Montheard: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Previtali: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Stepan: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Ogasawara: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Mack: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Abramson: Bluebird Bio: Consultancy; EMD Serono: Consultancy; Kymera: Consultancy; BeiGene: Consultancy; Incyte Corporation: Consultancy; Astra-Zeneca: Consultancy; Allogene Therapeutics: Consultancy; Seagen Inc.: Research Funding; AbbVie: Consultancy; Novartis: Consultancy; Kite Pharma: Consultancy; Morphosys: Consultancy; C4 Therapeutics: Consultancy; Bristol-Myers Squibb Company: Consultancy, Research Funding; Genmab: Consultancy; Karyopharm: Consultancy; Genentech: Consultancy. OffLabel Disclosure: Liso-cel is a CAR T cell therapy approved for use in the third line for R/R LBCL. This trial reports data from the pivotal trial in the second line.

Abstract Introduction: Clinical trials of novel salvage therapies (ST) have encouraging outcomes for relapsed/refractory classic Hodgkin lymphoma (R/R cHL) after autologous stem cell transplant (ASCT); yet studies comparing novel ST with conventional salvage chemotherapy are lacking. In a single center cohort, we demonstrated that bendamustine/brentuximab (BBV) had higher overall response rates (ORR) and complete response (CR) rates in ASCT-eligible R/R cHL (Desai et al JCO, 2021). Herein we report comparative outcomes of novel and conventional ST in R/R cHL who undergo ASCT, in a large multicenter retrospective cohort. Methods: Consecutive R/R cHL pts who underwent ASCT at 12 institutions across United States were included. Demographics and clinical variables at relapse including age, sex, B symptoms, stage, bulky disease (BD, single mass &gt; 6 cm) extra nodal disease (END), primary refractory disease (PRD) and early relapse (ER, within 1 year) were recorded by electronic health records review. Study objectives were ORR, CR to first ST, post-ASCT PFS and OS by final ST. Time to event endpoints were defined from date of ASCT. Results: From 12 participating institutions, 853 pts of R/R cHL who underwent ASCT were eligible for this study. Median age was 33 (14-72) years, 457 (54%) were male, 446 (52%) had BD, 257 (30%) had advanced stage, 271 (32%) had END, 369 (43%) had B symptoms, 142 (17%) had PRD and 307 (36%) had ER. All 853 received at least 1 ST, 245 received 2 ST, 71 received 3 ST and 26 received 4 ST. Seven groups of ST were identified: 1. Conventional platinum-based chemotherapy (PBC) group including ICE, DHAP and ESHAP 2. BBV 3. Brentuximab Vedotin and nivolumab (BV/Nivo) 4. BV alone (BV) 5. gemcitabine-based chemotherapy (Gem) 6. checkpoint inhibitors (CPI) and 7. other miscellaneous agents (Misc). 1st ST was as follows: 553 had PBC; 69 had BBV; 48 had BV/Nivo; 65 had BV; 49 had Gem; 4 had CPI and 63 had Misc. There was no significant difference in the baseline characteristics by type of 1 st ST (data not shown). BBV had significantly higher ORR (92% vs 79%, p&lt;0.001) and CR rate (80% vs 49%, p &lt;0.001) compared to PBC. BV/Nivo had significantly higher CR rate (67% vs 49%, p &lt;0.001) and a trend towards higher ORR (86% vs 79%, p = 0.1) compared to PBC. BV had significantly lower ORR (62% vs 79%, p &lt;0.001) and CR rate (34% vs 49%, p &lt;0.001) compared to PBC. There was no difference in ORR and CR rate of PBC, Gem, CPI and Misc agents. Final ST prior to ASCT was PBC in 451, BBV in 76, BV/Nivo in 48, BV in 87, CPI in 24, Gem in 90 and Misc in 64. Table 1 lists K-M estimates of 2-year survival probabilities for different Final ST groups. Median follow up was 3 (range 0.1-13) years. BV/Nivo group had significantly higher proportion of patients with PRD and BD than PBC, no other differences in baseline characteristics were identified amongst ST groups (data not shown). BV/Nivo (HR: 0.1 (CI 95:0.02-0.4), p&lt;0.01) and CPI (HR: 0.12 (CI 95:0.03-0.5), p&lt;0.01) had significantly higher PFS than PBC. There was no significant difference in PFS between other ST groups (Figure 1a). Type of ST was not significantly associated with difference in OS (Figure 1b). 536 pts underwent ASCT in CR, 273 underwent ASCT in partial response (PR) and 31 underwent ASCT with progressive disease (PD). Pre-ASCT PR (HR 1.6 (CI 95:1.3-2.6), p&lt;0.001) and PD (HR: 4.1 (CI 95: 2.5-6.8), p&lt;0.001) predicted significantly lower PFS compared to CR (Figure 2a). OS was also significantly lower in pts with pre-ASCT PR (HR 1.7 (CI 95: 1.2-1.6), p&lt;0.001) and PD (HR 5.3 (CI 95: 2.8-10), p&lt;0.001) (Figure 2b). Higher number of pre-ASCT ST predicted lower PFS (HR 1.3 (CI 95: 1.1-1.6), p&lt;0.001) and OS (HR 1.5 (CI 95: 1.2-1.8), p&lt;0.001). In pts with pre-ASCT CR, all 36 who had pre-ASCT CR after BV/Nivo were alive and relapse free for follow up of 0.1-5 yrs. BV/Nivo was associated with significantly higher PFS (HR 0.1 (CI 95: 0.01-0.7), p &lt;0.05) but not OS compared to PBC in this subgroup. Increasing number of pre-ASCT ST predicted worse PFS (HR 1.5 (CI 95: 1.2-2.0), p&lt;0.01) and OS (HR 2.2 (CI 95: 1.4-3.4), p&lt;0.001) in this subgroup as well. Conclusions: BV/Nivo has a higher CR rate and better post-ASCT PFS compared to conventional chemotherapy and can lead to durable remissions in pts with pre-ASCT CR. BBV had a higher response rate and similar post-ASCT survival to conventional chemotherapy. BV had lower response rates compared to chemotherapy. Novel ST such as BV/Nivo and BBV may be preferable to conventional chemotherapy in R/R cHL. Figure 1 Figure 1. Disclosures Spinner: Notable Labs: Honoraria. Bachanova: FATE: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Research Funding; KaryoPharma: Membership on an entity's Board of Directors or advisory committees; Gamida Cell: Membership on an entity's Board of Directors or advisory committees, Research Funding. Dorritie: SITC presentation: Honoraria; Genmab: Research Funding; University of Pittsburgh/UPMC Hillman Cancer Center: Current Employment; Janssen: Research Funding; F. Hoffman-La Roche Ltd: Research Funding; Juno/BMS: Research Funding; Kite, a Gilead Company: Research Funding; OncLive/Institutional Perspectives on Cancer presentation: Honoraria. Arai: Magenta Therapeutics: Research Funding. Maurer: Nanostring: Research Funding; Morphosys: Membership on an entity's Board of Directors or advisory committees, Research Funding; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; Celgene: Research Funding; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees. Diefenbach: Genentech, Inc./ F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Research Funding; IMab: Research Funding; Morphosys: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Merck Sharp & Dohme: Consultancy, Honoraria, Research Funding; Perlmutter Cancer Center at NYU Langone Health: Current Employment; AbbVie: Research Funding; IGM Biosciences: Research Funding; Incyte: Research Funding; Trillium: Research Funding; Gilead: Current equity holder in publicly-traded company; MEI: Consultancy, Research Funding. Nowakowski: Kyte Pharma: Consultancy; Ryvu Therapeutics: Consultancy; Selvita: Consultancy; Curis: Consultancy; Karyopharm Therapeutics: Consultancy; Celgene/Bristol Myers Squibb: Consultancy, Research Funding; Roche: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; MorphoSys: Consultancy; Bantham Pharmaceutical: Consultancy; Daiichi Sankyo: Consultancy; Zai Labolatory: Consultancy; Incyte: Consultancy; Kymera Therapeutics: Consultancy; TG Therapeutics: Consultancy; Blueprint Medicines: Consultancy; Nanostrings: Research Funding. Advani: Astellas/Agensys: Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Bristol Myer Squibb: Membership on an entity's Board of Directors or advisory committees; Cell Medica: Membership on an entity's Board of Directors or advisory committees; Forty Seven: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genetech Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceutical: Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Kura: Research Funding; Kyowa: Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Millenium: Research Funding; Pharmacyclics: Consultancy, Research Funding; Portola Pharmaceuticals: Consultancy; Regeneron: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees.

7541 Background: FT516 is an investigational, NK cell cancer immunotherapy derived from a clonal master iPSC line. FT516 is engineered with a novel hnCD16 Fc receptor, demonstrated preclinically to maximize antibody-dependent cellular cytotoxicity (Zhu et al. Blood 2020). FT516 can be mass produced and made available off-the-shelf for broad pt access and multi-dose administration. Methods: This is a Phase I trial of FT516 combined with rituximab (R) in pts with R/R BCL. Treatment consists of 2 cycles, each with 3 days lympho-conditioning (fludarabine 30 mg/m 2 and cyclophosphamide 500 mg/m 2 ) and 1 dose of R followed by 3 weekly infusions of FT516 (planned doses 30-900 million/dose) with IL-2 (6 MIU after each FT516 dose). The primary objective is to identify the incidence of dose-limiting toxicity (DLT)/dose cohort and the recommended Phase II dose using a standard 3+3 design. Additional objectives include safety, tolerability, preliminary activity, pharmacokinetics, and immunogenicity. Results: Six pts (5 DLBCL, 1 FL, median age 65.5 y) have completed (5) or discontinued (1) study treatment after the DLT period (data cutoff 9 Dec 2020): 2 received 30 million cells/dose, 3 received 90 million cells/dose, and 1 received 300 million cells/dose. All pts received > 1 prior R-containing regimen, and median number of prior therapies was 3 (range 2-6), including CAR-T in 3 pts. FT516 was primarily administered in the outpatient setting. No FT516-related Grade ≥3 adverse events (AEs) or serious AEs, and no events of cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), or graft-versus-host disease (GvHD) of any grade were reported. DLT (Grade 4 neutrophil count decreased, not recovered to baseline by D29) was reported in the first pt at 30 million cells/dose and R dosing of 375 mg/m 2 weekly x 4/cycle, resulting in modification of R dosing to once/cycle; no DLTs were observed with modified R dosing. Most common all grade AEs in ≥3 pts: fatigue (4 pts) and decreased appetite, nausea, neutrophil count decreased, and headache (3 pts each). Grade ≥3 AEs in ≥2 pts: neutrophil count decreased (3 pts) and febrile neutropenia and platelet count decreased (2 pts each); none considered related to FT516. Host anti-product B- or T-cell immunogenicity was not observed. Three of 4 pts treated at ≥90 million cells/dose achieved objective response (2 complete responses [CRs] and 1 partial response). Conclusions: Administration of up to 6 doses of FT516 cells, including up to 300 million cells/dose, appears to be safe and tolerable, without CRS, ICANS, or GvHD. Activity was observed, including CRs, in heavily pretreated pts. Dose escalation is ongoing. Updated clinical and translational data will be presented. Clinical trial information: NCT04023071.

AbstractIntroductionWhile most patients with mantle cell lymphoma (MCL) receive therapy shortly after diagnosis, a subset of patients with indolent‐behaving disease can safely defer treatment. In this subgroup, we evaluated the importance of treatment intensity in patients with MCL who defer initial therapy.MethodsOut of 1134 patients with MCL from 12 academic centers, we analyzed 219 patients who initiated therapy at least 90 days after diagnosis. Patients who received induction with high‐dose cytarabine and/or autologous stem cell transplantation (ASCT) in first remission were considered to have received intensive therapy (n = 88) while all other approaches were non‐intensive (n = 131).ResultsThere was no difference in progression‐free (PFS; P = .224) or overall survival (OS; P = .167) in deferred patients who received non‐intensive vs. intensive therapy. Additionally, univariate and multivariate Cox proportional hazards models were performed for PFS and OS. Treatment at an academic center (HR 0.43, P = .015) was associated with improved OS in both univariate and multivariate models, while intensity of treatment was not associated with improved OS in either model.ConclusionsThese results indicate that intensified initial treatment is not associated with improved survival after deferring initial therapy, although prospective studies are needed to determine which of these patients with MCL may benefit from intensive therapy.