Siegel, David S.

Abstract Chimeric antigen receptor (CAR) T-cell therapy enriched for a memory-like phenotype may persist and function longer than a nonenriched product, thereby improving duration of response (DOR). We conducted a phase I study with bb21217 (NCT03274219), an anti–B-cell maturation antigen CAR T-cell therapy manufactured in the presence of the phosphoinositide 3-kinase inhibitor bb007 to enrich for T cells with a memory-like phenotype, in patients with relapsed/refractory multiple myeloma (N = 72). No new safety concerns were raised with bb21217 therapy (three cases each of grade ≥3 cytokine release syndrome and grade ≥3 neurotoxicity were observed). The objective response rate was 69.4% and the median DOR was 23.8 (95% confidence interval, 16.8–34.8) months. Analysis of the drug product established an association between early memory phenotype and robust expansion and depth of response. Examination of baseline characteristics indicated that tumor burden and prior therapies influenced DOR. The data indicate that generation of CAR T cells early in a disease course when tumor burden is lower and source material exhibits a more naïve phenotype may maximize the clinical benefit potential of the drug product.

Background Polyclonal autologous T cells that are epigenetically reprogrammed through mTOR inhibition and IFN-α polarization (RAPA-201) represent a novel approach to the adoptive T cell therapy of cancer. Ex vivo inhibition of mTOR results causes a shift towards T central memory (TCM) whereas ex vivo IFN-α promotes type I cytokines, with each of these functions known to enhance the adoptive T cell therapy of cancer. Rapamycin-resistant T cells polarized for a type II cytokine phenotype were previously evaluated in the allogeneic transplantation context. Methods The clinical trial (NCT04176380) evaluated RAPA-201 therapy in combination with fludarabine-sparing low-dose host conditioning for the treatment of patients with relapsed, refractory multiple myeloma (RRMM). Results From December 2020 to December 2022, 14 patients with RRMM received a median of three RAPA-201 infusions (median dose, 80×106 cells). RAPA-201 drug products (DPs) were: polyclonal; enriched for TCM cells; reduced for immune checkpoint expression, including PD1, CD73, and LAIR1; and preferentially secreted Th1 cytokines. The median chemotherapy dose administered per cycle was 1,817 mg total for cyclophosphamide (range, 1,100–2,200) and 2.35 mg/M2 for pentostatin (range, 0–16). Nine of 14 patients (64%) achieved disease remission, with eight partial responses and one stringent complete response. Median progression-free survival was 6.0 months (range, 2.1 to>16.8 months). There were no toxicities of any grade attributable to RAPA-201, including no cytokine release syndrome and no immune effector cell-associated neurotoxicity syndrome. Only 4 of 14 patients (29%) had a serious adverse event (≥ grade 3) of any attribution. Conclusions Consistent with our hypothesis, ex vivo manufacturing using mTOR inhibition and IFN-α polarization consistently yielded a novel RAPA-201 DP that possessed a desirable phenotype relative to cytokine phenotype, memory status, and checkpoint expression. RAPA-201 recipients had preservation of T cell counts and Th1 cytokine secretion yet had increased T cell receptor clonality that associates with antitumor responses in the setting of monoclonal antibody checkpoint therapy. RAPA-201 therapy overcomes previous barriers to effective autologous polyclonal T-cell therapy, as it is feasible to manufacture, exquisitely safe to administer, and mediates remission in patients with RRMM. Trial registration number ClinicalTrials.gov: NCT04176380.

Introduction Induction therapy (Tx) followed by ASCT and lenalidomide (LEN) maintenance is the standard of care in transplant-eligible pts with NDMM. Pts who have suboptimal response after front-line ASCT, however, have an increased risk of progression or death. Ide-cel demonstrated significantly improved median progression-free survival (PFS) and overall response rate (ORR) vs standard regimens in KarMMa-3 in pts with early-line triple-class-exposed relapsed and refractory multiple myeloma (MM). KarMMa-2 (NCT03601078) is a multicohort, phase 2, multicenter trial evaluating the efficacy and safety of ide-cel in several MM disease settings; cohort 2c includes pts with NDMM who achieved < very good partial response (VGPR) after front-line ASCT. An extended follow-up analysis (median follow-up of 39.4 months) of cohort 2c was presented at ASH 2023 (Dhodapkar M, et al. ASH 2023; P2101). Here, we report results with 55.4 months of median follow-up and additional data on pts who received LEN maintenance at the investigator's discretion. Methods Adult pts with NDMM who received ≥ 3 cycles of induction Tx (proteasome inhibitor, immunomodulatory agent, dexamethasone), and had < VGPR 70-110 days after ASCT (single/tandem) were eligible. Pts received a single ide-cel infusion (150-450 × 106 chimeric antigen receptor-positive T cells) and could receive maintenance Tx post-infusion at investigator discretion. The primary endpoint was complete response rate (CRR); secondary endpoints included ORR, duration of response (DOR), PFS, overall survival (OS), safety, cellular kinetics, and patient-reported outcomes on health-related quality of life (HRQoL). Minimal residual disease (MRD) negativity (sensitivity, 10-5), an exploratory endpoint, is also reported. Results At data cutoff (June 28, 2024), with a median follow-up of 55.4 (range, 51.4-59.5) months, all 31 pts treated with ide-cel were alive; 28 (90.3%) remained in follow-up and 3 (9.7%) discontinued due to disease progression or withdrawal by pt. Eight pts received LEN maintenance after ide-cel at the investigator's discretion. Among all 31 ide-cel-treated pts, CRR and ORR were 80.6% and 87.1%, respectively. Among the 8 pts who received LEN maintenance, CRR and ORR were 75.0% and 100.0%, respectively. Median DOR, PFS, and OS were not reached; 36-month event-free rates were 81.5%, 76.8%, and 100.0%, respectively. Of the 8 pts who received LEN maintenance after ide-cel infusion, none experienced disease progression. At 36 months, MRD negativity was confirmed in 12/18 (66.7%) evaluable pts; all 12 achieved ≥ CR. Since last data cutoff, 1 pt with MRD-negative MM changed to MRD-positive at 36 months, and 1 pt who had previously achieved MRD negativity was indeterminate at 36 months. Among the 6 evaluable pts who received LEN maintenance, 3/6 (50.0%) achieved MRD negativity at 36 months. There were no new safety signals nor reports of parkinsonism or Guillain-Barré syndrome since the previous data cutoff. In the 8 pts who received LEN maintenance, 6 (75.0%) experienced grade 3/4 AE, most commonly neutropenia, and 1 (12.5%) experienced grade 3/4 infection on or after LEN maintenance. All 8 pts were still receiving LEN at data cutoff. Robust CAR+ T cell expansion was observed in 31 pts, with higher expansion in pts with ≥ CR vs < CR. Following ide-cel treatment, HRQoL improved and disease symptoms were stable over time (assessed by European Organization for Research and Treatment of Cancer [EORTC] Quality of Life Core Questionnaire and EORTC Quality of Life Multiple Myeloma Module 20 Questionnaire). More than 75% of pts had improved or stable global health status/QoL by month 3. Conclusions With extended follow-up, ide-cel continued to demonstrate deep, durable responses in pts with < VGPR to front-line ASCT. No new safety signals were observed and no deaths were reported. Data in a small group of pts in cohort 2c showed that ide-cel followed by LEN maintenance extended disease control. Pts who received LEN maintenance did not experience disease progression regardless of MRD status. Stable or improved HRQoL was observed after ide-cel treatment. Overall, ide-cel continued to show a favorable clinical benefit-risk profile in NDMM after ASCT. The phase 3 KarMMa-9 study (NCT06045806), currently recruiting, will compare ide-cel followed by LEN maintenance vs LEN maintenance alone in pts with NDMM after suboptimal response to ASCT.

Background: Despite recent major advances, multiple myeloma (MM) remains incurable using therapies that are currently available to patients. There are no available/approved targeted therapies for MM that allow for individualized therapeutic approaches to the disease. Fifteen to 20% of newly diagnosed MM patients have a translocation of chromosomes 4 and 14 [t(4;14)]. This translocation puts transcription of the gene encoding Multiple Myeloma SET domain-containing protein (MMSET or NSD2), a histone 3 lysine 36 methyltransferase, under the control of the IgH super enhancer. The super enhancer drives the overexpression of MMSET resulting in an abnormal histone code that promotes myelomagenesis. Presence of t(4;14) is associated with poor clinical prognosis (Caro Am Soc Clin Oncol Educ Book 2021). KTX-1001 is a first-in-class, selective and potent small molecule inhibitor of MMSET, and is the first investigational drug that targets the t(4;14) MM patient population. Methods: This Phase 1, first-in-human open-label study (NCT05651932) is designed to assess the safety, tolerability, and initial clinical activity of KTX-1001 in relapsed/refractory MM (RRMM) and has two parts: dose escalation (Part A) and dose expansion (Part B). In Part B, only t(4;14)+ MM patients will be evaluated in single agent and combination expansion cohorts. Patients with RRMM who have received ≥3 prior lines of therapy, including a proteasome inhibitor (PI), immunomodulatory drug (IMiD), and anti-CD38 antibody are eligible for the dose escalation part. The primary objective of the study is to determine a recommended phase 2 dose (RP2D) and schedule of KTX-1001. Secondary and exploratory objectives include pharmacokinetic (PK) and pharmacodynamic (PD) evaluation of KTX-1001, and assessment of preliminary efficacy. KTX-1001 is administered orally until disease progression, unacceptable toxicity, or patient withdrawal from the study. A Safety Review Committee (SRC) reviews all data prior to each dose escalation decision and on a regular basis. Results: As of June 14, 2024, 17 patients (pts) have been treated with KTX-1001 in Part A across 6 dose levels (SRC reviewed). Dose Level 7 has been reached with no dose limiting toxicities (DLTs). Ten of these patients are t(4;14) positive. Patients have received a median of 5 prior lines of therapy (range: 3-17), including 7 pts with prior BCMA CAR-T, 6 pts with prior BCMA bispecific and/or ADC, 5 pts with prior non-BCMA bispecific, and 12 pts with prior transplant. Patient demographics include a median age of 68 years (range: 50-83), 10 male/ 7 female, 13 white, 2 black or African American, 2 as other identified race, and 3 Hispanic or Latino pts. Six pts remain on treatment. KTX-1001 shows excellent tolerability to date, with treatment emergent AEs (TEAEs) (CTCAEv5.0) predominantly of grade 1 and 2 severity. Most frequently observed TEAEs suspected to be related to KTX-1001 include fatigue (35%), diarrhea (24%), and constipation (24%), for which no grade 3 or 4 events have been observed. Frequency and/or severity of TEAEs have not increased with escalating doses nor treatment duration, and no patients have discontinued due to an AE. Two heavily pre-treated patients [one known to be t(4;14)+] have demonstrated long-lasting stable disease and clinical benefit at 10 and 7 months respectively. Both patients have been intra-patient dose escalated. For PK and PD data collected to date, drug exposure and steady-state concentration of KTX-1001 (at C1D15, when steady state concentration has been reached) appear to be dose-proportional. PD data indicate a dose-dependent decrease in the H3K36me2 mark on treatment versus baseline across dose levels 1 through 6, suggesting that the RP2D may be reached by year end. Updated results will be presented at the congress. Conclusions: Dose escalation of KTX-1001 is ongoing with an excellent tolerability profile to date and demonstration of on-target pharmacodynamics that will inform the determination of the RP2D(s). These PD data support the targeted mechanism of action of KTX-1001 to selectively inhibit MMSET and break the t(4;14) histone code. Given KTX-1001's promising safety profile, single-agent and combination expansion cohorts with standard-of-care MM agents/classes will begin in 2025 to further optimize doses and provide proof of concept in Part B of the Phase 1 study.

Introduction Multiple myeloma (MM) is considered incurable. Despite improved outcomes with novel agents, including BCMA-targeted chimeric antigen receptor (CAR) T-cell therapies, antibody-drug conjugates (ADCs), and bispecific antibodies, patients with relapsed/refractory MM (RRMM) often have poor prognoses. LINKER-MM1 (NCT03761108) is a global, single-arm, Phase 1/2 study of linvoseltamab, a BCMA×CD3 bispecific antibody, in patients with RRMM who were either triple-class exposed (TCE; previously treated with a proteasome inhibitor, immunomodulatory drug, and anti-CD38 antibody) during ≥3 prior lines of therapy (LOTs), or triple-class refractory to these therapies. Here, we present comparisons of clinical outcomes from LINKER-MM1 with those of a current, international, real-world (RW) external control arm (ECA; NCT05673967). Methods The ECA was derived from 16 academic sites of the International Myeloma Foundation International Myeloma Working Group (IMWG) (N=203; 309 eligible LOTs) and compared with linvoseltamab (N=105; Phase 2 200 mg cohort). Patients in the ECA initiated ≥1 anti-MM therapy after meeting key LINKER-MM1 eligibility criteria. Weighted random sampling and inverse probability of treatment weighting were used to select 1 LOT per patient and balance the ECA and trial populations on prespecified prognostic factors (Kumar S, et al. IMS 2023). The primary endpoint was objective response rate (ORR; IMWG criteria) determined by an independent central review committee (ICRC) based on myeloma laboratories. An independent data review committee reviewed comparability of cohorts and endpoint assessments prior to conducting comparative analyses. Results Median follow-up was 14.3 months for the linvoseltamab cohort (data cutoff: Jan 6, 2024) and 13.4 months for the ECA. After weighting, 15 prognostic factors were balanced between cohorts. Patients in the ECA received 68 distinct regimens, most commonly CAR T-cell therapies (11.3%) and ADCs (10.3%). After balancing the cohorts, patients in the ECA evaluable for response had ICRC-assessed ORR of 46.3% (40.8% by treating physician assessment), among whom 24.0% had very good partial response or better (≥VGPR). When including patients who died without evaluable response, ECA ICRC-assessed ORR was 44.2%. Linvoseltamab induced significantly higher ICRC-assessed ORR (69.5% vs 46.3%, odds ratio [OR] 2.65 [95% confidence interval (CI) 1.66-3.69]) and rate of ≥VGPR (62.9% vs 24.0%, OR 5.37 [95% CI 3.61-8.49]) compared with ECA regimens. Conclusion Despite current use of novel therapies, there is no well-established RW standard of care (SOC) for patients with TCE RRMM treated at IMWG sites. To our knowledge, this is the first RW ECA study in MM with a high percentage of anti-BCMA therapies and response ascertainment for all patients by ICRC. Linvoseltamab induced significantly higher response rates, including rate of ≥VGPR, compared with current RW SOC therapies, highlighting its potential as a highly effective treatment in patients with TCE RRMM.

Introduction Linvoseltamab is an investigational, BCMA×CD3 bispecific antibody designed for the treatment of RRMM. High objective response rates (ORR) to linvoseltamab 200 mg in the LINKER-MM1 trial (NCT03761108) were demonstrated across high-risk subgroups, including patients aged ≥75 years, patients with high-risk cytogenetics, and patients with penta-class refractory status. The aim of this study was to compare ORR, overall and in key subgroups, between patients in Phase 2 of the LINKER-MM1 trial and patients in an international RW SOC external control arm (ECA). Methods The ECA was derived from a chart review of 16 academic sites across 10 countries that are part of the International Myeloma Foundation (IMF)-International Myeloma Working Group (IMWG) and 2 US electronic health record databases (COTA and Guardian Research Network [GRN]). Included patients initiated ≥1 anti-MM treatment after meeting key eligibility criteria of LINKER-MM1. Weighted random sampling and inverse probability of treatment weighting (IPTW) were used to select 1 line of therapy (LOT) per patient and balance the overall ECA and trial populations on prespecified prognostic factors (Kumar S, et al. IMS 2023). For ORR assessment, LINKER-MM1 and IMF-IMWG used independent central review committees per IMWG criteria, COTA used algorithmic assessment based on IMWG criteria, and GRN used physician-assessed responses. Prior to conducting comparative analyses, an independent committee of epidemiology and oncology experts reviewed the comparability of the cohorts and endpoint assessments, and approved study continuation. ORR among patients in LINKER-MM1 and patients in the ECA was compared overall and across prespecified subgroups (≥10 patients per subgroup), including age, race, cytogenetic risk score, international Staging System (ISS), presence of extramedullary plasmacytoma (EMP), refractory class, bone marrow plasma cell (BMPC) proportion, and number of prior LOTs. Results Median duration of follow-up was 14.3 months (data cut-off: January 6, 2024) for patients receiving linvoseltamab (n=105) and 13.6 months for the ECA (n=307; n=194, n=72, and n=41 from IMF-IMWG, COTA, and GRN, respectively). Following IPTW, 13 prognostic factors with <30% missingness were balanced between cohorts, with an effective sample size in the ECA of 197. After adjustment, ORR was significantly higher in patients who received linvoseltamab compared with patients in the ECA (69.5% vs 45.7%, odds ratio [OR] 2.5 [95% confidence interval (CI) 1.6-4.1]) and in key subgroups with age 65-74 years (76.9% vs 48.3%, OR 3.6 [1.6-8.6]), age ≥75 years (72.4% vs 48.5%, OR 2.8 [1.1-7.4]), Black or African American race (82.4% vs 25.0%, OR 14.0 [3.0-85.4]), White race (68.9% vs 49.7%, OR 2.2 [1.3-4.0]), standard cytogenetic risk (72.3% vs 51.3%, OR 2.5 [1.3-4.8]), ISS stage III (58.8% vs 19.7%, OR 5.8 [1.5-25.2]), absence of EMP (71.6% vs 49.3%, OR 2.6 [1.5-4.6]), triple-class refractory status (68.2% vs 45.7%, OR 2.6 [1.5-4.4]), quadruple-class refractory status (66.7% vs 45.9%, OR 2.4 [1.3-4.3]), 4-5 prior LOTs (65.1% vs 40.4%, OR 2.8 [1.3-6.0]), and >5 prior LOTs (75.7% vs 36.1%, OR 5.5 [2.4-13.6]). Numerically higher (not statistically significant) or similar ORR was observed for patients receiving linvoseltamab compared with patients in the ECA with age <65 years (59.5% vs 46.8%, OR 1.7 [0.79-3.6]), high-risk cytogenetics (65.0% vs 63.1%, OR 1.1 [0.41-2.9]), ISS stage I (73.3% vs 64.6%, OR 1.5 [0.62-3.7]), ISS stage II (67.6% vs 53.5%, OR 1.8 [0.72-4.7]), presence of EMP (58.8% vs 56.9%, OR 1.1 [0.32-3.8]), penta-class refractory status (64.3% vs 48.5%, OR 1.9 [0.78-4.8]), BMPC <50% (77.0% vs 67.2%, OR 1.6 [0.61-4.3]), BMPC ≥50% (41.7% vs 36.0%, OR 1.3 [0.36-4.7]), and ≤3 prior LOTs (68.0% vs 66.4%, OR 1.1 [0.43-2.9]). Separate findings will be presented for IMF-IMWG and COTA/GRN data at the congress. Conclusions Linvoseltamab induced better ORR vs RW SOC treatments overall, and better or similar ORR in the key subgroups assessed, highlighting its therapeutic value across a range of patients with RRMM with heterogeneous risk profiles and levels of disease burden.

Background: Despite the development and approval of effective therapies for multiple myeloma (MM), MM remains an incurable disease. Moreover, patients with high-risk cytogenetics, like translocation t(4;14), continue to have a poor prognosis compared to standard-risk patients. No novel agents have been approved specifically for this population. There remains an unmet need for precision therapies for MM that can target specific drivers of high-risk MM like t(4;14). Multiple myeloma SET domain-containing protein (MMSET) overexpression observed in 100% of patients with t(4;14) acts through the MMSET-H3K36me2 axis, which promotes malignant transformation through regulation of multiple oncogenic programs. KTX-1001, a methyl transferase inhibitor, is a novel, first-in-class, potent, oral, small molecule that inhibits MMSET and the methylation of lysine K36. KTX-1001 had favorable drug-like properties, demonstrated in vivo activity, and was well tolerated in non-clinical studies. Based on these data, KTX-1001 is now being studied in a Phase 1 dose escalation and expansion study in relapsed and refractory multiple myeloma (RRMM). Study Design and Methods: This multi-country, Phase 1, open-label study (NCT05651932) is designed to assess the safety, tolerability, and initial clinical activity of KTX-1001. The study will also examine the recommended phase 2 dose (RP2D), pharmacokinetics (PK) and pharmacodynamics (PD). Part A of this trial includes an accelerated titration, followed by 3+3 dose escalation with backfill of cohorts for dose optimization prior to moving to Part B, which is an expansion phase at the RP2D (please see Figure 1 for study design schematic). The expansion phase will only include patients with t(4;14). KTX-1001 will be administered orally daily and given until disease progression, unacceptable toxicity, or withdrawal from the study. Estimated enrollment for Parts A and B will be approximately 60 patients. The study will enroll patients with RRMM who have received ≥3 prior lines of therapy, including a proteasome inhibitor (PI), immunomodulatory drug (IMiD), and anti-CD38 antibody. Patients must have measurable disease, be ≥18 years of age, have an Eastern Cooperative Oncology Group score of ≤2, and adequate bone marrow, liver, and kidney function. Key exclusion criteria include history of or current plasma cell leukemia, active central nervous system (CNS) disease, or active unstable cardiovascular function. The primary endpoints of safety and tolerability include incidence of dose-limiting toxicity (DLTs), treatment-emergent adverse events (AEs), and treatment-related AEs. Secondary endpoints include plasma concentrations of KTX-1001 and efficacy outcomes such as objective response rate (ORR), duration of response (DOR), progression-free survival (PFS), and overall survival (OS). Exploratory biomarker and pharmacodynamic assessments will also be performed. The sample size was not determined by formal statistical methods but will be sufficient to provide preliminary information on safety, PK, PD, and efficacy. Statistical analyses will be primarily descriptive. Conclusion: This Phase 1 study will evaluate a potential treatment for RRMM utilizing KTX-1001, which is a novel, first-in-class, potent, oral small-molecule MMSET inhibitor. The study is open and actively enrolling patients at centers in the United States, Spain, France, and Canada.

Introduction Patients (pts) with multiple myeloma (MM) have a higher risk of progression/death following an inadequate response to frontline ASCT (van de Velde Eur J Haematol 2017). Therapies (Tx) with novel mechanisms of action may further improve response outcomes. Ide-cel previously demonstrated frequent, deep, and durable responses in KarMMa (Munshi N Engl J Med 2021) and significantly improved median progression-free survival (PFS) and overall response rate (ORR) versus standard regimens in KarMMa-3 (Rodríguez-Otero N Engl J Med 2023) in pts with triple-class-exposed relapsed and refractory MM. KarMMa-2 (NCT03601078) is a multicohort, phase 2, multicenter trial evaluating the efficacy and safety of ide-cel in pts with MM; cohort 2c included pts with NDMM who had an inadequate response to frontline Tx with ASCT. In cohort 2c, with a median follow-up of 27.9 months, ide-cel demonstrated deep and durable responses; complete response (CR) rate was 74.2% (ORR, 87.1%), with a 24-month PFS rate of 83.1% (Dhodapkar Blood 2022). Here, we report results with an additional 11.5 months of median follow-up for updated efficacy and safety data, and health-related quality of life (HRQoL) outcomes in cohort 2c. Methods Eligible pts had NDMM, received ≥ 3 cycles of induction Tx (including a proteasome inhibitor, an immunomodulatory agent, and dexamethasone), had < very good partial response (VGPR) 70-110 days after ASCT (single/tandem), and had Eastern Cooperative Oncology Group performance status ≤ 1. Pts received a single infusion of ide-cel (dose range: 150-450 × 10 6 CAR+ T cells) after lymphodepletion and could receive maintenance Tx post-infusion at investigator's discretion. The primary endpoint CR rate and secondary endpoints ORR, duration of response (DOR), PFS, overall survival (OS), safety, and patient-reported outcomes on HRQoL, assessed via European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Core 30 Questionnaire (QLQ-C30) and EORTC Quality of Life Multiple Myeloma Module 20 Questionnaire (QLQ-MY20), are reported. The exploratory endpoint of minimal residual disease (MRD) negativity (sensitivity, 10 -5) is also reported. Results At data cutoff (May 3, 2023), with a median follow-up of 39.4 (range, 31.6-44.7) months, all 31 pts who were infused with ide-cel were alive; 28 (90.3%) remained in follow-up, with 3 (9.7%) having discontinued due to disease progression. The ORR and CR rates were 87.1% and 77.4%, respectively ( Table); best overall response in 1 pt improved from VGPR to stringent CR. The median DOR was not reached (NR; 95% CI, NR-NR), neither was median PFS (95% CI, 38.0-NR) or median OS (95% CI, NR-NR); the 36-month event-free rates were 80.9%, 76.8%, and 100.0%, respectively. In pts who did not receive lenalidomide (LEN) maintenance, 9 (29.0%) had disease progression; of the 8 pts who received LEN maintenance post ide-cel infusion, none experienced disease progression. At 36 months, MRD negativity was confirmed in 9/14 (64.3%) evaluable pts; all 9 achieved ≥ CR. In this extended follow-up, safety results were generally consistent with the previous data cutoff. All pts experienced ≥ 1 any-grade adverse event (AE), most commonly hematologic, including neutropenia (80.6%), anemia (38.7%), leukopenia (32.3%), and thrombocytopenia (29.0%); infection and infestation AEs occurred in 74.2% of pts. No grade 5 AEs were reported. Incidence of any-grade cytokine release syndrome (58.1%; no grade ≥ 3) was unchanged and there were no additional reports of parkinsonism since the previous report. Overall, HRQoL improved ( Figure) and MM disease symptoms were stable over time based on the EORTC QLQ-C30 and QLQ-MY20, respectively, following ide-cel treatment; by month 3, > 75% of pts had improved or stable global health status/QoL. Conclusions Ide-cel continued to demonstrate deep, durable responses in pts with an inadequate response to frontline ASCT, no new safety signals were observed with extended follow-up, and no deaths were reported. No pts who received LEN maintenance post ide-cel experienced disease progression. Ide-cel treatment resulted in stable or improved HRQoL. Overall, ide-cel continued to demonstrate a favorable clinical benefit-risk profile in NDMM after ASCT. Study support 2seventy bio and Celgene, a Bristol-Myers Squibb Company.