Michot, Jean‐Marie

e19046 Background: While outcomes in pts with R/R FL have improved with current SOC treatments (Tx), there remains a need for safe, efficacious, and convenient Tx options. GOLCA is a potential, first-in-class, oral CELMoD designed for Tx of lymphoma, with preferential distribution to lymphoid organs and enhanced activity in lymphoma cell lines. GOLCA induces rapid and deep degradation of Ikaros and Aiolos, leading to direct cell killing and immunomodulatory activity. GOLCA + R was well tolerated and effective in heavily pretreated pts in the two-part Ph 1/2 study, CC-99282-NHL-001. Here, we provide longer f/u in pts with R/R FL from Part B of the study. Methods: Pts with R/R FL with ≥2 prior lines of Tx (≥1 if prior anti-CD20 Tx) received GOLCA orally, once daily at 0.2 mg (n=22) or 0.4 mg (n=38) ± R for up to 2 y or until progressive disease (PD)/unacceptable toxicity. Primary endpoints included safety and RP2D determination; secondary endpoints are preliminary efficacy and PK. Results: As of September 15, 2025, 60 pts were enrolled. In 0.2 and 0.4 mg groups, median prior Tx lines were 3 and 3, 32% and 32% had prior lenalidomide (LEN), 27% and 29% had prior T-cell–redirecting Tx (CAR T and/or bispecific antibody) and 32% and 32% were refractory to last regimen. Tx is ongoing in 6 (27%) and 17 (45%) pts at 0.2 and 0.4 mg, respectively; discontinuations (d/c) were mostly due to PD. Neutropenia, an on-target side effect of GOLCA, was the most common grade 3/4 Tx-emergent adverse event (TEAE) occurring in 59% and 68% of pts at 0.2 and 0.4 mg, followed by anemia (9% and 16%) and febrile neutropenia (9% and 8%). Median time to resolution of neutropenia was 8 days. Dose reductions occurred in 14% and 37% of pts at 0.2 and 0.4 mg, most commonly due to neutropenia (5% and 21%) and febrile neutropenia (5% and 5%). No d/c or deaths were from GOLCA-related TEAEs. Non-hematologic TEAEs were infrequent and mostly low grade. In efficacy-evaluable pts (GOLCA 0.2 and 0.4 mg + R, n=22 and n=36), median f/u was 14.03 months (mo), overall response rate (ORR) was 77% (complete response rate [CRR], 41%) at 0.2 mg, and 97% (CRR, 78%) at 0.4 mg. In the 0.4 mg group, responses were consistent in high-risk subsets including pts with prior LEN (ORR, 100%; CRR, 75%) and/or T-cell–redirecting Tx (ORR, 91%; CRR, 64%). GOLCA 0.4 mg + R demonstrated durable responses (median DOR, 9.17 mo; 91% of pts who achieved a CR remained in CR at cutoff). Conclusions: With longer f/u, GOLCA + R demonstrated promising efficacy with durable responses and no new safety signals. The 0.4 mg group had higher ORR and CRR than 0.2 mg, including in pts with prior LEN-based and/or T-cell–redirecting Tx, with a manageable safety profile at both doses. The results support the development of GOLCA + R as a fixed-duration, chemotherapy-free outpatient Tx in the Ph 3 GOLSEEK-4 study in 2L+ FL (NCT06911502). Clinical trial information: NCT03930953 .

Abstract Introduction While outcomes in patients with R/R FL have improved with T-cell–redirecting treatments (e.g. CAR T-cell therapy, bispecific antibodies), there remains an unmet need for safe, efficacious, and more convenient chemotherapy-free treatment options (Caridà et al, Eur J Haematol. 2025). GOLCA is a potential, first-in-class, oral CELMoD agent designed for the treatment of lymphoma, with preferential distribution to lymphoid organs and enhanced activity in lymphoma cell lines. GOLCA drives the closed, active conformation of cereblon to induce rapid and deep degradation of Ikaros and Aiolos, leading to direct cell killing (agnostic of cell of origin) and immunomodulatory activity. In the two-part, multicenter, first-in-human Phase 1/2 study (CC-99282-NHL-001; NCT03930953), GOLCA was well tolerated and effective in patients with R/R FL (Cordoba et al, ICML 2025, #441). Here, we provide longer follow-up in patients with R/R FL from Part B of the study. Methods Patients with R/R FL with ≥ 2 prior lines of therapy (≥ 1 in Part B if prior anti-CD20 therapy) were included in the study. Patients received GOLCA monotherapy orally, once daily at different dosing schedules in Part A. In Part B, GOLCA was dosed at 0.2 or 0.4 mg (14 days on/14 days off) ± R. Total GOLCA treatment duration was up to 2 years or until progressive disease (PD)/unacceptable toxicity. Primary objectives included safety and recommended Phase 2 dose determination. Results As of April 3, 2025, a total of 72 patients with R/R FL were enrolled: 12 in Part A (GOLCA monotherapy) and 60 in Part B Cohort D (22 received GOLCA 0.2 mg + R; 38 received GOLCA 0.4 mg + R). Patients were heavily pre-treated. Median number of prior treatments was 4.5 (range, 2–6) in Part A and 3 (range, 1–12) in Part B Cohort D. Approximately one-third of the treated patients were exposed to prior T-cell–redirecting therapy, approximately one-third had prior lenalidomide (len) exposure, and approximately one-third were refractory to the last regimen received. At the time of data cutoff, in Part A, 4 patients completed 2 years of GOLCA, remaining in remission at last follow-up; 8 discontinued due to PD. In Part B Cohort D, 41% of patients treated with 0.2 mg and 63% with 0.4 mg were ongoing. PD was the most common reason for discontinuation. In the safety evaluable population (n = 60; GOLCA 0.2 or 0.4 mg + R), neutropenia, an on-target side effect of GOLCA, was the most common grade 3/4 treatment-emergent adverse event (TEAE) and occurred in 65% of patients, followed by anemia (13%) and febrile neutropenia (8%). Serious AEs related to GOLCA occurred in 22% of patients, most commonly infections (17%) and febrile neutropenia (7%); pulmonary embolism occurred in 1 patient with 0.2 mg. The most common causes of GOLCA interruption in the overall safety population were infections (32%) and neutropenia (18%). Dose reductions were mostly due to neutropenia (10%) and febrile neutropenia (5%). No discontinuations or deaths occurred from GOLCA-related TEAEs. Non-hematologic TEAEs were infrequent and mostly low grade, with the most common being gastrointestinal disorders (7%). In the efficacy evaluable patients (n = 56; GOLCA 0.2 or 0.4 mg + R) at a median follow-up of 10.8 months, the overall response rate (ORR) was 89% (complete response rate [CRR], 61%). With 0.2 mg, ORR was 81% (CRR, 43%) and with 0.4 mg, ORR was 94% (CRR, 71%). In the 0.4-mg group, responses were consistent in high-risk subsets, including patients with prior len (ORR, 100%; CRR, 73%) and/or T-cell–redirecting therapy (ORR, 91%; CRR, 64%). With GOLCA 0.4 mg, 10 patients had response lasting > 12 months, including 5 with prior T-cell–redirecting therapy and 6 with prior len. Conclusions With additional follow-up, GOLCA + R continued to show promising efficacy with durable responses and no new safety signals. A higher ORR/CRR and similar tolerability were observed with GOLCA 0.4 mg + R vs GOLCA 0.2 mg + R, including in patients with prior len-based and/or T-cell–redirecting treatment. These data support continued development of GOLCA 0.4 mg + R as a fixed-duration, chemotherapy-free, outpatient option in the ongoing Phase 3 GOLSEEK-4 study in 2L+ FL (NCT06911502).

Abstract Introduction LINVO, a human B-cell maturation antigen (BCMA)xCD3 bispecific antibody, was recently approved for triple-class exposed (TCE) RRMM after ≥3 prior therapies (EU) or ≥4 prior lines of therapy (US), demonstrating high efficacy and a generally manageable safety profile. Combining LINVO with an anti-CD38 mAb, such as DARA or ISA, may provide additional benefit to pts with RRMM. Here we report pooled safety and efficacy results from the LINVO + DARA and LINVO + ISA cohorts during the dose-finding portion of the Phase 1b LINKER-MM2 trial (NCT05137054). Methods Eligible pts were aged ≥18 years with RRMM that progressed after ≥3 lines of therapy (LoTs), or ≥2 LoTs if TCE or double-class refractory (immunomodulatory drug [IMiD] + proteasome inhibitor [PI]). Prior treatment (tx) with DARA or ISA was allowed if previously tolerated and ≥6 months (mos) or ≥3 mos washout, respectively, had elapsed since last exposure. Tx began with LINVO monotherapy (Cycle [C]0; 28-day cycle) consisting of 2 step-up doses (5 mg, 25 mg) and 2 full doses (dose level [DL]1 100 mg; DL1b 150 mg; DL2 200 mg) before standard dosing of DARA or ISA was added at C1. LINVO was given once weekly in C1–3 and once every 2 weeks in C4+. At the end of 2024, dosing once every 4 weeks was implemented after C6 if a very good partial response or better (≥VGPR) was achieved. Dexamethasone premedication was required during the first 2 cycles and then given per label for DARA or ISA. Primary endpoints: dose-limiting toxicities (DLTs) and tx-emergent adverse events (TEAEs). Key secondary endpoints: overall response rate (ORR), duration of response (DOR), progression-free survival (PFS), and rate of minimal residual disease (MRD) negativity. The analyses reported here combine the LINVO + DARA and LINVO + ISA cohorts. Results As of May 7, 2025, 42 pts were enrolled. All pts were included in the safety analysis set: DL1 (DARA, n=12; ISA, n=6), DL1b (n=6; n=10), or DL2 (n=8; n=0); 37 were included in the efficacy analysis set: DL1 (DARA, n=11; ISA, n=5), DL1b (n=5; n=9), or DL2 (n=7; n=0). At baseline, all pts had received ≥1 PI (refractory to ≥1 PI: 76%) or ≥1 IMiD (refractory to ≥1 IMiD: 86%), and 21 pts (50%) had received prior DARA or ISA (refractory to DARA or ISA: 33% [DARA, n=4; ISA, n=10]). Median number of prior LoTs was 3 (range 2–8), including 50% of pts with TCE and 21% with triple-class refractory disease. Median age was 68 years (range 42–86); male, 57%; ISS stage III at study entry, 12%; high-risk cytogenetics, 31%; bone marrow plasma cells ≥50%, 31%; and soft tissue plasmacytomas, 33% (extramedullary, 12%). Median follow-up duration was 14.8 mos for DL1 (DARA 21.3; ISA 11.3), 7.6 mos for DL1b (DARA 13.5; ISA 5.2), and 5.9 mos for DL2 (all DARA), with 44%, 50%, and 63% of pts still receiving tx, respectively. The most common TEAEs were anemia (any grade [Gr] 48%; Gr 3/4 26%), neutropenia (41%; 41%), diarrhea (38%; 2%), and thrombocytopenia (38%; 17%). Cytokine release syndrome was reported in 33% of pts (all Gr 1/2 events except 1 Gr 3 event during the step-up period that fully resolved). No pts experienced immune effector cell-associated neurotoxicity syndrome (ICANS). Infections were reported in 32 pts (any Gr 76%; Gr ≥3 40%), and 3 resulted in death (1 tx related: cytomegalovirus [CMV] pneumonia; 2 tx unrelated: C. diff colitis and lower respiratory infection). One DLT was observed at DL1b in the ISA cohort (Gr 3 Epstein–Barr virus pharyngitis) and 1 was observed at DL2 in the DARA cohort (Gr 5 CMV pneumonia). Among efficacy evaluable pts, ORR was 75% at DL1 (12/16; ≥VGPR rate 75%), 93% at DL1b (13/14; ≥VGPR rate 57%), and 86% at DL2 (6/7; ≥VGPR rate 86%). Of 10 MRD-evaluable pts, all were MRD negative (<10−5by clonoSEQ or EuroFlow). The 12-mo DOR rate was 79% (95% confidence interval [CI] 52–92; median DOR not reached) and 12-mo PFS rate was 73% (95% CI 53–86; median PFS not reached). Pharmacokinetic analyses showed LINVO concentrations were not affected by the addition of DARA or ISA. ConclusionsIn pts with heavily pretreated RRMM, half of whom had prior anti-CD38 mAb exposure, the combination of LINVO and DARA or ISA was feasible, inducing a high rate of deep and durable responses, and exhibiting a safety profile similar to that reported for each individual drug. These preliminary data support continued development of LINVO plus an anti-CD38 mAb for the tx of pts with MM.

Abstract Patients with relapsed/refractory diffuse large B-cell lymphoma progressing after chimeric antigen receptor T-cell (CAR-T) therapy have dismal outcomes. The prespecified post–CAR-T expansion cohort of the ELM-1 study investigated the efficacy and safety of odronextamab, a CD20×CD3 bispecific antibody, in patients with disease progression after CAR-Ts. Sixty patients received IV odronextamab weekly for 4 cycles followed by maintenance until progression. The primary end point was objective response rate (ORR) by independent central review. The median number of prior lines of therapy was 3 (range, 2-9), 71.7% were refractory to CAR-Ts, and 48.3% relapsed within 90 days of CAR-T therapy. After a median follow-up of 16.2 months, ORR and complete response (CR) rate were 48.3% and 31.7%, respectively. Responses were similar across prior CAR-T products and time to relapse on CAR-T therapy. Median duration of response was 14.8 months and median duration of CR was not reached. Median progression-free survival and overall survival were 4.8 and 10.2 months, respectively. The most common treatment-emergent adverse event was cytokine release syndrome (48.3%; no grade ≥3 events). No cases of immune effector cell–associated neurotoxicity syndrome were reported. Grade ≥3 infections occurred in 12 patients (20.0%), 2 of which were COVID-19. Odronextamab monotherapy demonstrated encouraging efficacy and generally manageable safety, supporting its potential as an off-the-shelf option for patients after CAR-T therapy. This trial was registered at www.clinicaltrials.gov as #NCT02290951.

Introduction: GOLCA is a potential first-in-class CELMoDTM agent for the treatment of lymphoma, purposefully designed to target the proteins Ikaros/Aiolos to produce dual immunomodulatory and anti-tumor activity, with preferential distribution to lymphoid organs. Pharmacodynamic data in pts with R/R FL show that, combined with RTX, the immunomodulatory effects of GOLCA are significantly increased (Chavez et al, EHA 2024, #1132). GOLCA as monotherapy (mono) and + RTX has been shown to be well-tolerated and effective in pts with R/R DLBCL (Chavez et al, ASH 2023, #4496) and R/R FL (Chavez et al, EHA 2024, #1132). Here, we report 30 mo follow up of pts with R/R FL who received GOLCA mono, and updated safety/efficacy of GOLCA + RTX from the ongoing Phase 1/2 CC-99282-NHL-001 study (NCT03930953). Methods: Pts with R/R FL with ≥ 2 prior lines of therapy (L) received GOLCA mono at different dosing schedules during part A (dose exploration) and GOLCA ± RTX at 0.2 mg or 0.4 mg days (d) 1-14 every 28 d (q28d) in part B (dose expansion). Total treatment duration with GOLCA was up to 2 years or until progressive disease or unacceptable toxicity, whichever occurred first. The efficacy-evaluable population consisted of pts completing ≥ 1 cycle of GOLCA and having baseline tumor assessment and ≥ 1 post-baseline tumor assessment or clinical progression or disease-related death. Results: As of May 31, 2024, 63 pts with R/R FL have enrolled: GOLCA mono (n = 19) at various dosing schedules and GOLCA + RTX at 0.2 mg (n = 22) or 0.4 mg (n = 22) on d1-14 q28d schedule. The median time from diagnosis to first dose of GOLCA was 68 mo (range, 23-136) and 59 mo (range, 15-309) in GOLCA mono and + RTX cohorts, respectively. The median number of prior therapies received was 4 (range, 2-11), and 3 (range, 1-12) in GOLCA mono and + RTX cohorts, respectively. In the GOLCA mono and + RTX cohorts, 9/19 (47%) and 13/43 (30%) pts had received prior lenalidomide (len)-based therapy, with 5/9 and 7/13 having len-refractory disease, respectively. In the GOLCA + RTX cohort, 10/43 (23%) had prior CAR T cell therapy and 6/43 (14%) had prior anti-CD20xCD3 bispecific antibody with or without CAR T cell therapy. In the GOLCA + RTX-treated safety population (n = 43), the incidence of treatment emergent adverse events (TEAEs) was similar across 0.2 and 0.4 mg dose levels (DL). The most frequent grade (G) 3+ TEAEs were neutropenia (44%) and anemia (12%). The incidence of febrile neutropenia was 7%. Serious adverse events occurred in 30% of pts, with febrile neutropenia and pneumonia being the most common, in 2 pts (5%) each, as well as pulmonary embolism in 1 pt. Neutropenia led to GOLCA dose interruption in 4 pts (9%) and dose reduction in 1 pt (2%). No pts discontinued treatment because of GOLCA-related TEAEs. Non-hematological TEAEs (e.g., GI toxicity, rash, fatigue) were all low-grade (except 1 pt with G3 fatigue). There were no new safety signals identified for GOLCA mono (part A) at the 30-mo follow up period. In the efficacy-evaluable population, at a median follow up of 6 mo (range 3-18), the ORR and CRR in the GOLCA + RTX cohort (n = 29) were 57% and 29% at 0.2 mg dose (n = 14) and 93% and 67% at 0.4 mg dose (n = 15), respectively. The median time to response was 2 mo (first response assessment). At the 0.4 mg DL of GOLCA + RTX, consistent responses were seen in pts at 2L/3L and 4L+, including in those with prior exposure to len-based therapies and/or T-cell-redirecting therapy. At the 0.4 mg DL, 12/14 (86%) pts remained in response at the time of data cut-off. In pts receiving GOLCA mono across different dose schedules in part A (n = 12), ORR and CRR were 67% and 42%, respectively. Responses were durable, with median DOR of 22 mo (range, 2-51) at a median follow up of 30 mo. 33% of pts (4/12) have completed 2 yrs of protocol defined GOLCA treatment and remain in response at the 1 yr post-treatment follow-up period, without requiring any intervening treatment. Conclusions: GOLCA 0.4 mg + RTX was well tolerated and highly active in heavily pre-treated pts with R/R FL, including those with prior exposure to len-based therapies and/or T-cell-redirecting therapies. Treatment with fixed-duration GOLCA mono led to durable responses including a subset of pts remaining treatment free, without progression at extended follow up. These data further support development of GOLCA + RTX as a fixed-duration, chemotherapy-free, outpatient treatment option in pts with R/R FL, and also pts with newly diagnosed advanced stage FL (NCT06425302).

Introduction CD19-directed CAR T-cell therapies are an important option for the management of relapsed/refractory (R/R) DLBCL. Studies suggest that ~50% of pts receiving CAR T-cell therapies will relapse within 6 months, with an estimated overall survival (OS) of only 5 months. Additionally, 25-35% of pts do not receive subsequent treatment, indicating a high unmet need. CD19 loss is a potential mechanism of resistance to CAR T-cell therapies; thus, treatments that target alternate B-cell antigens are an attractive option. Here, we report for the first time the primary analysis of the ELM-1 expansion cohort investigating the efficacy and safety of odronextamab, a CD20×CD3 bispecific antibody, in pts with R/R DLBCL progressing after CAR T-cell therapy (NCT02290951). Methods Pts aged ≥18 with DLBCL and disease progression after CAR T-cell therapy received intravenous odronextamab weekly in 21-day (D) cycles during Cycles (C) 1-4, with steroid prophylaxis and step-up dosing in C1 (described previously), followed by 160 mg on D 1, 8, and 15 of C2-4. After C4, odronextamab maintenance treatment continued at 320 mg Q2W until disease progression or unacceptable toxicity. Pts with complete response (CR) for ≥9 months transitioned to Q4W dosing. All pts received infection prophylaxis. The primary analysis was conducted when all pts had completed ≥9 months of follow-up. Primary endpoint was objective response rate (ORR), as 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. Exploratory endpoints included immune biomarker assessment. Results As of January 22, 2024, 60 pts were treated and evaluable for efficacy and safety, with median follow-up of 16.2 months. Prior CAR T-cell therapies were axi-cel (50%), tisa-cel (12%), liso-cel (10%), and not specified (28%). Median time since prior CAR T-cell therapy was 6.5 months (range 1.2-46.2). Median age was 63 years (range 27-82; aged ≥75 years: 10%), and 65% were male. Pts had received a median of 3 prior lines of therapies (range 2-9); 77% of pts were refractory to their last therapy, 77% were double refractory, and 72% were refractory to prior CAR T-cell therapy. 48% of pts relapsed within 90 D of CAR T-cell therapy, and 67% relapsed within 180 D. Of the 20 pts with available tumor biopsies at baseline, 10 were CD19(-) and only 2 were CD20(-). 92% of pts completed C1 and 52% completed ≥4 C of treatment. The median duration of treatment was 12 weeks (range 0.7-154.1). The ORR and CR rate by ICR were 48% and 32%, respectively, and were consistent across pts with high-risk features and across prior CAR T products. ORR in pts relapsing in ≤90 D was 21% (6/29) and in pts relapsing in ≤180 D was 33% (13/40). ORR was observed even in pts with low CD20. Median DOR was 14.8 months (95% CI 2.8-not estimable [NE]) and median duration of CR was not reached (NR) (95% CI 3.3-NE); the probability of maintaining CR for 24 months was 68%. Median PFS was 4.8 months (95% CI 2.6-5.4) and median OS was 10.2 months (95% CI 4.6-15.8). Median PFS and OS in complete responders was NR. T-cell counts increased at Week 14 and demonstrated a functional phenotype (CD69 expression and TEMRA count), which was confirmed by ex vivo stimulation. T-cell expansion was observed regardless of CAR T product or time from CAR T administration. The most common TEAE was CRS (any grade [G]: 48%; G1: 25%; G2: 23%; G≥3: 0%). G≥3 TEAEs occurred in 77% of pts (most common: neutropenia 17%, anemia 13%, and neutrophil and white blood cell count decrease 10% each). Five pts (8%) permanently discontinued odronextamab due to AEs (COVID-19, pneumonia, encephalopathy, epilepsy, and gait disturbance [n=1 each]). There was one treatment-related death (COVID-19 pneumonia). No cases of ICANS were reported. G≥3 infections occurred in 12 pts (20%); 2 were due to COVID-19. No cases of tumor flare or TLS were reported. Conclusions ELM-1 is the only study to prospectively evaluate efficacy and safety of a CD20×CD3 bispecific antibody in pts with R/R DLBCL progressing after CAR T-cell therapy. Odronextamab monotherapy was associated with encouraging efficacy and generally manageable safety in a setting with limited treatment options and historically dismal outcomes. Efficacy was observed even in pts relapsing in ≤90 D, supporting the potential of odronextamab as an accessible, off-the-shelf option in the post-CAR T setting.

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 Introduction: Plamotamab (XmAb13676) is a humanized bispecific antibody that binds both CD20 and CD3 to recruit cytotoxic T cells to kill CD20 expressing malignant cells. Interim results of an ongoing first-in-human (FIH), dose-escalation study (XmAb13676-01; NCT02924402) in subjects with relapsed/refractory (R/R) non-Hodgkin's lymphoma (NHL) are reported. Methods: The study is an FIH, multi-center, open-label, phase 1, dose-escalation study in subjects with R/R NHL with a standard 3 + 3 design. The primary objectives are to determine safety, tolerability, and the maximum tolerated dose (MTD) or recommended dose of plamotamab. Secondary objectives include preliminary anti-tumor activity and pharmacokinetics/pharmacodynamics of plamotamab. This study has 3 Parts: Part A, escalating dose cohorts that establish an initial priming dose as part of repeated weekly infusions at a fixed, weight-based dose in a 28-day cycle; Part B, with a dosing schedule consisting of a priming dose on Cycle 1 Day 1, established in Part A, followed by step-up dosing (SUD) on subsequent weeks; and Part C is an SUD regimen with flat and less frequent dosing. Cytokine release syndrome (CRS) prophylaxis with dexamethasone, antihistamine, and acetaminophen was mandated prior to each administration of plamotamab. Treatment was continued for 2 cycles or longer if there was evidence of therapeutic benefit. Results: At data cut-off (01Jul2021), 80 subjects with NHL have been treated. Subjects had a median age of 62 years (range 32-89), a median of 4 prior therapies (range 1-10), and had been diagnosed a median of 28 months (range 6-353) prior to treatment in the study. The most common treatment-related adverse event was CRS. Overall, 50 subjects (62.5%) experienced CRS, with 4 (5.0%) experiencing Grade ≥ 3 CRS. No related neurotoxicity >Grade 2 has been observed. Treatment responses for NHL were assessed by the Lugano criteria or International Working Group criteria for Waldenström Macroglobulinemia. There have been 23 objective responses (43.4% overall response rate [ORR]) and 13 (38.2%) at doses of ≥ 80 µg/kg or flat dosing in all evaluable subjects with NHL and diffuse large cell B-cell lymphoma, respectively. In the efficacy-evaluable, follicular lymphoma population, at doses of 80-360 µg/kg or flat dosing, objective responses were observed in 8/10 (80%) subjects. After implementation of flat dosing, as opposed to weight-based dosing, a 50% ORR (4/8 evaluable subjects) has been observed in NHL subjects in that cohort. An MTD has not been reached, and dose escalation is ongoing. Overall, 4 out of 16 (25%) evaluable subjects with prior CAR-T therapy responded to plamotamab. Conclusions: Plamotamab demonstrated evidence of clinical activity in heavily pretreated subjects with R/R NHL. CRS was generally manageable with premedication. The study is ongoing with further optimization of dose and schedule. Figure 1 Figure 1. Disclosures Patel: Kite Pharma: Consultancy, Speakers Bureau; Genentech: Consultancy; Morphosys: Consultancy; Bristol Myers Squibb: Consultancy, Speakers Bureau; BeiGene: Consultancy; Janssen: Consultancy; AstraZeneca: Consultancy, Research Funding, Speakers Bureau; Pharmacyclics: Consultancy; Abbvie: Consultancy; TG Therapeutics: Consultancy, Speakers Bureau; MEI Pharma: Consultancy; ADC Therapeutics: Consultancy; Lilly: Consultancy. Michot: GSK: Honoraria; Celgene: Honoraria; MSD: Consultancy, Honoraria; Innate Pharma: Research Funding; Incyte: Research Funding; H3 biomedecine: Research Funding; GSK: Consultancy, Honoraria, Research Funding; Genentech: Research Funding; Gamamabs: Research Funding; Forma: Research Funding; Exelixis: Research Funding; Eos: Research Funding; Eisai: Research Funding; Debiopharm: Research Funding; Daiichi Sankyo,: Research Funding; Clovis: Research Funding; Chugai: Research Funding; Boeringer Ingelheim: Research Funding; Celgene: Research Funding; Blueprint: Research Funding; Beigene: Research Funding; Bayer: Research Funding; Argen-x: Research Funding; Amgen: Research Funding; Agios: Research Funding; Aduro: Research Funding; Abbvie: Research Funding; ASTEX: Research Funding, Speakers Bureau; Astra Zeneca: Honoraria, Research Funding; Roche: Honoraria; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding. Chanan-Khan: Alpha2 Pharmaceuticals, NonoDev, Starton: Current holder of stock options in a privately-held company; Ascentage: Research Funding; Cellectar: Current equity holder in publicly-traded company; Alpha2 Pharmaceuticals: Patents & Royalties: Tabi; Ascentage, Starton, Cellectar, NonoDev, Alpha2 Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; BeiGene, Jansen, Ascentage: Honoraria; BieGene, Jansen, Ascentage: Consultancy. Ghesquieres: Janssen: Honoraria; Mundipharma: Consultancy, Honoraria; Roche: Consultancy; Celgene: Consultancy, Honoraria; Gilead Science: Consultancy, Honoraria. Byrd: Vincerx Pharmaceuticals: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Novartis, Trillium, Astellas, AstraZeneca, Pharmacyclics, Syndax: Consultancy, Honoraria; Newave: Membership on an entity's Board of Directors or advisory committees. Cartron: Roche, Celgene-BMS: Consultancy; Danofi, Gilead, Novartis, Jansen, Roche, Celgene-BMS, Abbvie, Takeda: Honoraria. Portell: Acerta/AstraZeneca: Research Funding; Xencor: Research Funding; SeaGen: Research Funding; Targeted Oncology: Honoraria; Aptitude Health: Honoraria; Abbvie: Research Funding; Pharmacyclics: Honoraria; Kite: Honoraria, Research Funding; Merck: Honoraria, Research Funding; BeiGene: Honoraria, Research Funding; Morphosys: Honoraria; TG Therapeutics: Honoraria, Research Funding; Genentech: Research Funding; VelosBio: Research Funding. Solh: Jazz Pharmaceuticals: Consultancy; Partner Therapeutics: Research Funding; BMS: Consultancy; ADCT Therapeutics: Consultancy, Research Funding. Wierda: Loxo Oncology, Inc.: Research Funding; GSK/Novartis: Research Funding; Pharmacyclics LLC, an AbbVie Company: Research Funding; Miragen: Research Funding; Sunesis: Research Funding; Gilead Sciences: Research Funding; KITE Pharma: Research Funding; Genentech: Research Funding; Janssen: Research Funding; Juno Therapeutics: Research Funding; Acerta Pharma Inc.: Research Funding; Xencor: Research Funding; AstraZeneca: Research Funding; Cyclacel: Research Funding; Oncternal Therapeutics, Inc.: Research Funding; Karyopharm: Research Funding; Genzyme Corporation: Consultancy; AbbVie: Research Funding. Johnson: Xencor: Current equity holder in publicly-traded company, Divested equity in a private or publicly-traded company in the past 24 months, Ended employment in the past 24 months. Garcha: Xencor: Current Employment, Current equity holder in publicly-traded company, Current holder of stock options in a privately-held company; Promedim: Ended employment in the past 24 months. Ribrag: AstraZeneca: Membership on an entity's Board of Directors or advisory committees; GSK: Research Funding; MSD Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Infinity Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Servier: Consultancy, Membership on an entity's Board of Directors or advisory committees; Argen-X: Research Funding; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Astex Pharmaceuticals: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees; Nanostring: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; PharmaMar: Honoraria, Membership on an entity's Board of Directors or advisory committees; Epizyme: Honoraria, Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees. Liebowitz: Xencor: Current Employment, Current equity holder in publicly-traded company, Divested equity in a private or publicly-traded company in the past 24 months. Phillips: Incyte: Consultancy, Other: received travel expenses from Incyte, Research Funding; ADCT, BeiGene, Bristol Myers Squibb, Cardinal Health, Incyte, Karyopharm, Morphosys, Pharmacyclics, Seattle Genetics: Consultancy; AbbVie: Consultancy, Research Funding; AstraZeneca: Consultancy; BMS: Consultancy, Research Funding; Genentech: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Consultancy, Research Funding.