Arnason, Jon

7013 Background: Liso-cel is an autologous, CD19-directed, 4-1BB CAR T cell product. In prespecified interim and primary analyses of TRANSFORM (NCT03575351), liso-cel showed significant improvements in efficacy vs SOC in pts with R/R LBCL. Here we report results after ~3-y FU. Methods: TRANSFORM is a randomized phase 3 study comparing liso-cel vs SOC (CT [R-DHAP, R-ICE, or R-GDP] then high-dose CT [HDCT] + ASCT) in adults aged ≤ 75 y with LBCL primary refractory to or relapsed ≤ 12 mo after first-line therapy and eligible for ASCT. Liso-cel arm pts underwent lymphodepletion followed by liso-cel (100 × 10 6 CAR + T cells). Bridging therapy was allowed. SOC arm pts received 3 cycles of CT; responding pts proceeded to HDCT + ASCT. Crossover to receive liso-cel was allowed for SOC arm pts if criteria were met. The primary endpoint was event-free survival (EFS) per independent review committee (IRC). Key secondary endpoints included CR rate and PFS per IRC, and OS. Endpoints were not statistically retested and are reported descriptively. Results: In total, 184 pts were randomized (92 per arm); baseline characteristics were reported (Abramson et al. Blood 2023). Median (range) FU was 33.9 mo (0.9–53.0). Median EFS, PFS, and duration of response (DOR) were longer for liso-cel vs SOC, similar to the primary analysis (Table). A total of 61 (66%) SOC arm pts crossed over to receive liso-cel. Median OS was not reached (NR) in either arm; 36-mo OS rates were numerically higher for liso-cel. Of 76 total deaths (liso-cel, n = 34; SOC, n = 42 [crossover pts, n = 33]), 10 occurred since the primary analysis (liso-cel, n = 6; SOC, n = 4 [all crossover pts]); most were due to disease progression or complications (n = 6). Safety results were consistent with the primary analysis. Cellular kinetics and B-cell aplasia will be presented. Conclusions: After median FU of 33.9 mo, liso-cel as 2L treatment in pts with primary refractory or early relapsed LBCL resulted in deepening of response and continued improvement in efficacy endpoints over SOC, confirming the ongoing benefit of liso-cel. Clinical trial information: NCT03575351 . [Table: see text]

Background Chimeric antigen receptor (CAR) T-cell therapies have recently been established as an important option for the management of relapsed/refractory (R/R) DLBCL. However, real-world studies suggest that approximately half of all patients (pts) receiving commercial CAR-T therapies will relapse within 6 months. These pts have a poor prognosis, with estimated overall survival (OS) of only 5 months, indicating a significant unmet need. Odronextamab is a novel, off-the-shelf, CD20×CD3 bispecific antibody that has demonstrated activity in both R/R follicular lymphoma and R/R DLBCL. We have previously reported encouraging results with odronextamab from the Phase 1 ELM-1 study (NCT02290951) in pts with R/R DLBCL post CAR-T therapy (Bannerji R, et al. Lancet Haematol. 2022). These results were consistent with the antitumor activity seen in pts with R/R DLBCL from the Phase 2 ELM-2 study (Kim WS, et al. ASH 2022). Here, we present an updated analysis of outcomes in a prespecified cohort of post CAR-T patients from ELM-1. Methods Intravenous odronextamab was administered weekly in 21-day cycles during Cycles (C) 1-4. Revisions to the step-up regimen were reported previously (Bannerji R, et al. Lancet Haematol. 2022). Odronextamab was administered with steroid prophylaxis and step-up doses of 0.7/4/20 mg during C1 to mitigate the risk of cytokine release syndrome (CRS), followed by 160 mg on Days (D) 1, 8, and 15 of C2-4. After C4, odronextamab maintenance treatment continued at 320 mg every 2 weeks until disease progression or unacceptable toxicity. Those pts who achieved a complete response (CR) that was durable for ≥9 months transitioned to dosing with 320 mg every 4 weeks. The primary endpoint was objective response rate (ORR), assessed by independent central review (ICR) according to the Lugano classification. Key secondary endpoints included duration of response (DoR), progression-free survival (PFS), and OS. Immune biomarker assessment was an exploratory endpoint. Results As of Dec 20, 2022, 46 pts were treated (safety-evaluable), with 44 pts evaluable for efficacy. For safety-evaluable pts, median age was 63 years (range 27-82), 67% male, 74% Ann Arbor stage III-IV, and 72% were refractory to CAR-T therapy administered in any prior line. 44 pts were evaluable for efficacy after 4.9 months median duration of follow-up. The ORR and CR rate by ICR were 48% (21/44) and 30% (13/44), respectively. Responses were durable, and both median DoR and median duration of CR were not reached. The probability of maintaining a response for 12 months was 62% and the probability of maintaining a CR for 9 months was 86%.A responder analysis of the subgroup of pts who achieved a CR will be presented. The CAR-T treated pts with DLBCL who were evaluable for biomarker analysis (n=10) had lower T-cell counts at baseline compared with CAR-T naive DLBCL pts (n=41 comparable pts who received odronextamab in ELM-2), yet the fold-change of T-cell expansion at C4D15 was greater in CAR-T treated pts versus CAR-T naive pts. T-cell dynamics, such as changes in activation, exhaustion, and memory subsets, will be presented. Safety was generally consistent with that previously reported. Six (13%) pts permanently discontinued odronextamab due to a treatment-emergent AE (device-related infection, pneumonia, dysphagia, gait disturbance, leukemia, and encephalopathy [n=1 each]). The most common treatment-emergent AE was CRS (any grade, 52%). The highest grade of CRS reported was Grade 2, and low-grade CRS events occurred in 46% of pts with the 0.7/4/20 mg step-up regimen. No cases of ICANS were reported in pts with the 0.7/4/20 mg regimen. Grade ≥3 infections occurred in 10 (22%) pts, with no Grade 5 events. No cases of tumor flare were reported. Conclusions Odronextamab monotherapy demonstrates encouraging antitumor activity in heavily pretreated pts who have progressed after CAR-T therapy, with a generally manageable safety profile. Durable CRs were achieved in this difficult-to-treat setting. These data support the potential role of odronextamab in the treatment paradigm for R/R DLBCL. Further studies to evaluate the optimal sequencing and combinations of odronextamab with CAR-T therapy are warranted.

Abstract Chimeric antigen receptor T-cell (CAR-T) therapy represents a major advance in cancer immunotherapy; however, it can be associated with life-threatening neurotoxicity linked to blood-brain barrier disruption and endothelial activation. Defibrotide was shown to reduce endothelial cell activation in vitro and is approved in the United States for treatment of veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) in patients with renal or pulmonary dysfunction after hematopoietic cell transplantation (HCT), and in the European Union for severe VOD/SOS after HCT in patients aged >1 month. Defibrotide may stabilize the endothelium during CAR-T therapy and reduce the rate of CAR-T–associated neurotoxicity. This phase 2 study evaluated the safety and efficacy of defibrotide for prevention of CAR-T–associated neurotoxicity in patients with relapsed/refractory large B-cell lymphoma receiving axicabtagene ciloleucel. Part 1 established the recommended phase 2 dose (RP2D; 6.25 mg/kg); 20 patients (from parts 1 and 2) receiving the RP2D were evaluable for efficacy. Rate of CAR-T–associated neurotoxicity by day 30 (primary end point) was ∼50%, lower than reported in the ZUMA-1 trial (64%). Median event duration of grade ≥3 neurotoxicity was 7 days. No unexpected defibrotide-related safety findings and defibrotide-related treatment-emergent adverse events or deaths were reported. Results showed modest reduction in rate of CAR-T–associated neurotoxicity and high-grade neurotoxicity event duration relative to historical data; however, reduction was unlikely to meet the primary end point, so the study was terminated early. Nevertheless, results contribute valuable data for potential therapeutic insight on the management of CAR-T–associated neurotoxicity. This trial was registered at www.clinicaltrials.gov as #NCT03954106.

Abstract This global phase 3 study compared lisocabtagene maraleucel (liso-cel) with a standard of care (SOC) as second-line therapy for primary refractory or early relapsed (≤12 months) large B-cell lymphoma (LBCL). Adults eligible for autologous stem cell transplantation (ASCT; N = 184) were randomly assigned in a 1:1 ratio to liso-cel (100 × 106 chimeric antigen receptor–positive T cells) or SOC (3 cycles of platinum-based immunochemotherapy followed by high-dose chemotherapy and ASCT in responders). The primary end point was event-free survival (EFS). In this primary analysis with a 17.5-month median follow-up, median EFS was not reached (NR) for liso-cel vs 2.4 months for SOC. Complete response (CR) rate was 74% for liso-cel vs 43% for SOC (P < .0001) and median progression-free survival (PFS) was NR for liso-cel vs 6.2 months for SOC (hazard ratio [HR] = 0.400; P < .0001). Median overall survival (OS) was NR for liso-cel vs 29.9 months for SOC (HR = 0.724; P = .0987). When adjusted for crossover from SOC to liso-cel, 18-month OS rates were 73% for liso-cel and 54% for SOC (HR = 0.415). Grade 3 cytokine release syndrome and neurological events occurred in 1% and 4% of patients in the liso-cel arm, respectively (no grade 4 or 5 events). These data show significant improvements in EFS, CR rate, and PFS for liso-cel compared with SOC and support liso-cel as a preferred second-line treatment compared with SOC in patients with primary refractory or early relapsed LBCL. This trial was registered at www.clinicaltrials.gov as #NCT03575351.

Abstract Lisocabtagene maraleucel (liso-cel) has shown promising efficacy in clinical trials for patients with relapsed/refractory large B-cell lymphoma (LBCL). We present health-related quality of life (HRQOL) results from the TRANSFORM study, the first comparative analysis of liso-cel vs standard of care (SOC) as second-line therapy in this population. Adults with LBCL refractory or relapsed ≤12 months after first-line therapy and eligible for autologous stem cell transplantation were randomized 1:1 to the liso-cel or SOC arms (3 cycles of immunochemotherapy in which responders proceeded to high-dose chemotherapy and autologous stem cell transplantation). HRQOL was assessed by European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire – 30 items and the Functional Assessment of Cancer Therapy-Lymphoma subscale. Patients with baseline and ≥1 postbaseline assessment were analyzed (liso-cel, n = 47; SOC, n = 43). The proportion of patients with meaningful improvement in global health status/quality of life (QOL) was higher, whereas deterioration was lower in the liso-cel arm vs SOC arm from day 126 to month 6. Mean change scores showed meaningful worsening in global health status/QOL at month 6, fatigue at day 29 and month 6, and pain at month 6 with SOC; mean scores for other domains were maintained or improved in both arms. Time to confirmed deterioration favored the liso-cel arm vs SOC arm in global health status/QOL (median: not reached vs 19.0 weeks, respectively; hazard ratio, 0.47; 95% confidence interval, 0.24-0.94). HRQOL was either improved or maintained from baseline in patients with relapsed/refractory LBCL in the liso-cel arm vs SOC arm as second-line treatment. This study is registered at clinicaltrials.gov as #NCT0357531.

Abstract Background: Pts with previously treated R/R aggressive LBCL have compromised health-related QOL (HRQOL). 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 a prespecified interim analysis of TRANSFORM (NCT03575351), a randomized, open-label, pivotal trial, liso-cel demonstrated statistically significant and clinically meaningful improvement in the primary endpoint of event-free survival and key secondary endpoints (complete response rate and progression-free survival) in adults with R/R LBCL after failure of first-line (1L) immunochemotherapy compared with SOC, with no new safety signals. Here we present results of the pt-reported outcomes (PRO) analysis from TRANSFORM. Methods: Adults (age ≤ 75 yrs) with R/R LBCL (≤ 12 mo after 1L therapy), who were eligible for autologous stem cell transplantation (ASCT), were randomized to receive either SOC (3 cycles of salvage chemotherapy [CT] and BEAM + ASCT for responding pts) or liso-cel after lymphodepletion. Crossover to receive liso-cel was allowed in the SOC arm for pts who failed treatment. The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire - 30 items (EORTC QLQ-C30) and the Functional Assessment of Cancer Therapy - Lymphoma Subscale (FACT-LymS) were administered at randomization (baseline) and on Days 29 (infusion of liso-cel or 2 cycles of salvage CT), 64 (1 mo post liso-cel or completion of CT), 126 (3 mos post liso-cel or 2 mos post ASCT), and Mo 6 and other prespecified timepoints up to Mo 36 or end of study. No PRO data were collected after crossover. The analysis was based on the PRO-evaluable population (pts with a baseline and ≥ 1 post-baseline assessment). Predefined thresholds determined clinically meaningful changes. Global health/QOL (GH/QOL), physical functioning, cognitive functioning, fatigue, pain, and FACT-LymS were the primary domains of interest based on their relevance to the study population and treatment. A linear mixed model for repeated measures (MMRM) analysis was performed to assess the between-treatment difference in overall least squares (LS) mean change from baseline for each primary domain, using data collected up to Day 126 for visits with a sample size per arm ≥ 10. Proportions of pts with meaningful change from baseline were assessed for each primary domain up to Mo 6. All analyses were descriptive only. Results: Of 184 randomized pts, 90 (49%) and 85 (46%), respectively, were included in the PRO-evaluable population for the EORTC QLQ-C30 (SOC vs liso-cel n=43 vs 47) and FACT-LymS (n=40 vs 45, respectively). The PRO assessment completion rate from baseline up to Mo 6 was ≥ 45%, which was lower than expected primarily due to operational challenges during the COVID-19 pandemic but was comparable for both arms. In the MMRM analysis, the liso-cel arm had more favorable overall LS mean changes from baseline to Day 126 than the SOC arm in most of the EORTC QLQ-C30 domains and FACT-LymS. In particular, the between-treatment differences for cognitive functioning (−2.09 vs 2.21) and fatigue (3.75 vs −1.95) for SOC versus liso-cel, respectively, exceeded the prespecified minimal important difference threshold (Table); in those domains, the SOC arm deteriorated while the liso-cel arm improved. In individual-level analyses, the proportion of pts with meaningful improvement for fatigue and GH/QOL was higher, while deterioration was lower, in the liso-cel arm versus SOC arm from baseline up to Mo 6 (Figure). At Mo 6, a higher proportion of pts experienced worsened fatigue (71% vs 18%) and a lower proportion experienced improved fatigue (29% vs 47%) in the SOC arm compared with the liso-cel arm; for GH/QOL, a higher proportion of pts worsened (57% vs 18%) and lower proportion improved (14% vs 53%), respectively. For the other primary domains, the proportions of pts with improvement or deterioration favored liso-cel or were similar between arms. Conclusions: Compared with SOC, liso-cel showed favorable improvement in most primary PRO domains, particularly EORTC QLQ-C30 cognitive functioning and fatigue and more pts showed PRO improvements and fewer showed deterioration by Mo 6 with liso-cel. The results were achieved despite only responders remaining in the SOC arm after salvage CT. HRQOL was either improved or maintained after liso-cel treatment in pts with R/R LBCL after failure of 1L therapy. Figure 1 Figure 1. Disclosures Abramson: Bristol-Myers Squibb Company: Consultancy, Research Funding; Morphosys: Consultancy; C4 Therapeutics: Consultancy; Kite Pharma: Consultancy; Kymera: Consultancy; Incyte Corporation: Consultancy; Bluebird Bio: Consultancy; Astra-Zeneca: Consultancy; Allogene Therapeutics: Consultancy; Novartis: Consultancy; EMD Serono: Consultancy; Genmab: Consultancy; Seagen Inc.: Research Funding; AbbVie: Consultancy; Karyopharm: Consultancy; Genentech: Consultancy; BeiGene: 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. 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. Liu: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Braverman: BMS: Current Employment, Current equity holder in publicly-traded company. Guo: Daiichi Sankyo: Consultancy; UCB: Consultancy; Janssen: Consultancy; Gilead: Consultancy; Bristol Myers Squibb: Consultancy; EMD Serono: Consultancy; Evidera: Current Employment. Shi: Bristol Myers Squibb: Consultancy. Kamdar: ADC Therapeutics: Consultancy; Adaptive Biotechnologies: Consultancy; TG Therapeutics: Research Funding; Genentech: Research Funding; AbbVie: Consultancy; KaryoPharm: Consultancy; Kite: Consultancy; AstraZeneca: Consultancy; SeaGen: Speakers Bureau; Celgene: Other; Genetech: Other; Celgene (BMS): Consultancy.

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 > 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 < 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 < 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.

BACKGROUND: Odronextamab (REGN1979) is a first-in-class, hinge-stabilized, fully human IgG4-based CD3 x CD20 bispecific antibody (bsAb) that has demonstrated encouraging safety, tolerability and preliminary efficacy in a first-in-human study of patients (pts) with relapsed/refractory (R/R) B-cell non-Hodgkin lymphoma (B-NHL). We report updated safety and efficacy data from the dose escalation and early dose expansion phase of the ongoing Phase (P)1 study (NCT02290951). METHODS: Odronextamab was administered using a step-up dose schedule consisting of an initial dose at Week (W)1, an intermediate dose at W2, and thereafter, a fixed weekly dose until W12 followed by maintenance Q2W dosing. Dexamethasone premedication was used to mitigate the risk for cytokine release syndrome (CRS). Key primary objectives were to assess safety and dose-limiting toxicities (DLTs), and to establish a maximum tolerated dose (MTD) and recommended P2 dosing regimen (RP2DR). Secondary objectives included a preliminary assessment of anti-tumor activity. RESULTS: As of Jun 25, 2020, 127 pts with R/R B-NHL have been treated at doses ranging from 0.03-320 mg. The study included pts with diffuse large B-cell lymphoma (DLBCL; n=71), follicular lymphoma (FL) Grade (Gr) 1-3a (n=37), mantle cell lymphoma (MCL; n=11), marginal zone lymphoma (n=6), and other B-NHLs (n=2). Pts were highly refractory (80.3%) and had received a median of 3 (range: 1‒11) prior lines of therapy; 29 pts (22.8%) received prior CAR T therapy (FL: 2; DLBCL: 25; MCL: 2) and 85 pts (66.9%) were double refractory to alkylator and anti-CD20 antibody, in any line of therapy. Median follow-up was 3.9 (0.4‒37.6) months (mo). No DLTs were reported during dose escalation and MTD was not reached with odronextamab doses up to 320 mg weekly. The most frequent treatment-related adverse events (AEs) of any grade were pyrexia (76.4%), CRS (62.2%), and chills (48.0%). Gr 3 CRS occurred in 8 pts (6.3%) and a Gr 4 CRS occurred in 1 pt (0.8%). Most of the CRS events occurred during the first 2 weeks of step-up dosing and resolved within a median of 2 days (range 1-41) with supportive care measures. No pts discontinued odronextamab treatment due to CRS. Gr 3 neurologic AEs were noted in 5 pts, of which only 3 (2.3%) were considered treatment-related: somnolence, syncope, and encephalopathy. None of these events required treatment discontinuation. There were no Gr 4 or higher neurologic AEs. Overall, 7 pts (5.5%) discontinued treatment due to treatment-related AEs. In pts with R/R FL Gr 1-3a, odronextamab demonstrated a broad window of therapeutic activity. In pts treated at doses of ≥5 mg (n=28), objective response rate (ORR) was 92.9%, and complete response (CR) rate was 75.0%; median duration of response (DoR) was 7.7 mo (range 0+-20.9+), with 13 of 21 CRs ongoing at last tumor assessment. The median duration of complete response (DoCR) was 8.1 mo (range 0+-19.9+) and follow-up is ongoing (Table). In pts with R/R DLBCL, encouraging activity was observed at higher odronextamab dose levels. In DLBCL pts who had not received prior CAR T therapy, treated at doses ≥80 mg (n=10), ORR and CR rate were 60%; median observed DoR was 10.3 mo (range 2.9-18.6+), with 4 of 6 CRs ongoing at last tumor assessment. The median DoCR was 9.5 mo (range 2.9-18.6+) and follow-up is ongoing. In DLBCL pts who were refractory to prior CAR T therapy, treated at doses ≥80 mg (n=21), ORR was 33.3%, and CR rate was 23.8%; median observed DoR was 2.8 mo (range 0+-18.9+), with 5 of 5 CRs ongoing at last tumor assessment. The median DoCR was 4.4 mo (range 0+-18.9+) and follow-up is ongoing. Based on an evaluation of preliminary antitumor activity and PK, RP2DR was identified for dose expansion cohorts. CONCLUSIONS: Odronextamab has demonstrated encouraging single agent antitumor activity in highly refractory pts with B-NHLs. Durable CRs have been observed in both indolent and aggressive B-NHL pts, including in pts refractory to CAR T therapy. Most CRs are ongoing at time of data cutoff, and updated data will be presented. Odronextamab has an acceptable safety and tolerability profile. Dexamethasone premedication and step-up dosing mitigates the risk for CRS and allows odronextamab administration up to 320 mg weekly without DLTs. A global P2 trial investigating odronextamab in R/R B-NHL is ongoing. Disclosures Bannerji: Regeneron Pharmaceuticals: Research Funding; AbbVie: Research Funding; Sanofi-Pasteur: Other: Spouse is employee; F. Hoffmann-La Roche Ltd/Genentech, Inc and Pharmacyclics LLC, an AbbVie Company: Research Funding. Allan:Acerta, Genentech, Abbvie, Sunesis, Ascentage, Pharmacyclics, Janssen, AstraZeneca, BeiGene: Consultancy; Abbvie, Janssen, AstraZeneca, Pharmacyclics: Honoraria; Celgene, Genentech, Janssen, TG Therapeutics: Research Funding. Arnason:Regeneron: Consultancy; Juno: Consultancy. Brown:Catapult: Consultancy; Sun: Research Funding; Loxo: Consultancy, Research Funding; Verastem: Consultancy, Research Funding; TG Therapeutics: Consultancy; Sunesis: Consultancy; Rigel Pharmaceuticals: Consultancy; Pfizer: Consultancy; Octapharma: Consultancy; Novartis: Consultancy; Nextcea: Consultancy; MEI Pharma: Consultancy; Kite: Consultancy; Juno/Celgene: Consultancy; Eli Lilly and Company: Consultancy; Dynamo Therapeutics: Consultancy; BeiGene: Consultancy; Gilead: Consultancy, Research Funding; Invectys: Membership on an entity's Board of Directors or advisory committees, Other: DSMC; Acerta: Consultancy; Genentech: Consultancy; Pharmacyclics: Consultancy; Morphosys: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other; Astra-Zeneca: Consultancy; Janssen: Honoraria; AbbVie: Consultancy. Advani:Celgene, Forty Seven, Inc., Genentech/Roche, Janssen Pharmaceutical, Kura, Merck, Millenium, Pharmacyclics, Regeneron, Seattle Genetics: Research Funding; Astra Zeneca, Bayer Healthcare Pharmaceuticals, Cell Medica, Celgene, Genentech/Roche, Gilead, KitePharma, Kyowa, Portola Pharmaceuticals, Sanofi, Seattle Genetics, Takeda: Consultancy. Ansell:Bristol Myers Squibb: Research Funding; Takeda: Research Funding; Trillium: Research Funding; ADC Therapeutics: Research Funding; Affimed: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; AI Therapeutics: Research Funding. O'Brien:Gilead, Pharmacyclics, TG Therapeutics, Pfizer, Sunesis: Consultancy, Research Funding; Kite, Regeneron, Acerta: Research Funding; Amgen, Astellas, Celgene, GlaxoSmithKline, Janssen Oncology, Aptose Biosciences Inc. Vaniam Group, AbbVie, Alexion, Verastem, Eisai, Juno Therapeutics, Vida Ventures: Consultancy. Duell:Morphosys: Research Funding. Martin:Sandoz: Consultancy; Karyopharm: Consultancy, Research Funding; Celgene: Consultancy; Teneobio: Consultancy; I-MAB: Consultancy; Bayer: Consultancy; Beigene: Consultancy; Cellectar: Consultancy; Incyte: Consultancy; Kite: Consultancy; Morphosys: Consultancy; Regeneron: Consultancy; Janssen: Consultancy. Li:Regeneron Pharmaceuticals, Inc: Current Employment, Current equity holder in publicly-traded company. Flink:Regeneron Pharmaceuticals, Inc: Current Employment, Current equity holder in publicly-traded company. Zhu:Regeneron Pharmaceuticals, Inc: Current Employment, Current equity holder in publicly-traded company. Weinreich:Regeneron Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Yancopoulos:Regeneron Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Sirulnik:Regeneron Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Chaudhry:Regeneron Pharmaceuticals, Inc: Current Employment, Current equity holder in publicly-traded company. Ambati:Regeneron Pharmaceuticals, Inc: Current Employment, Current equity holder in publicly-traded company. Topp:Amgen, Boehringer Ingelheim, KITE, Regeneron, Roche: Research Funding; Amgen, KITE, Novartis, Regeneron, Roche: Consultancy. OffLabel Disclosure: The data described in the abstract will report on use of odronextamab in a Phase 1 clinical trial of patients with B-NHL