Zudaire, Enrique

Ciltacabtagene autoleucel (cilta-cel) consists of autologous T cells genetically modified to express a two-binding domain chimeric antigen receptor (CAR). The target antigen of the CAR is B-cell maturation antigen (BCMA), which is highly expressed on malignant plasma cells (PC) from multiple myeloma subjects. In the Phase 1b/2 CARTITUDE-1 study, cilta-cel led to early, deep, and durable responses and was approved for the treatment of patients with relapsed or refractory multiple myeloma (RRMM) after four or more prior lines of therapy by FDA. Despite cilta-cel's outstanding overall response rate (97.9%) and duration of response (DOR) in RRMM patients, relapse still occurs. Biomarkers associated with this durable response and acquired resistance remain to be elucidated. We present updated correlative data from the CARTITUDE-1 study. At the ~3 year follow-up (October 2022 data cutoff), 97 patients had received a single infusion of cilta-cel (median 0.71 x10 6 cells/kg [range 0.52 x10 6-0.94 x10 6]); the median follow up was 33.4 months (range 1.5-45.2), median DOR was 33.9 months (95% CI, 25.5-not estimable [NE]) and median PFS was 34.9 months (95% CI, 25.2-NE) (Lin Y et al, ASCO 2023). Drug product (DP), baseline and on-treatment whole blood and bone marrow samples from enrolled patients were analyzed by methods including flow cytometry, MSD immunoassays, Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE-seq) and TCR sequencing. In CARTITUDE-1, the DP contained a mixture of transduced and non-transduced T cells; the median transduction efficiency was 16% (range 5-32%), with a balanced distribution of CAR+CD4+ and CAR+CD8+ cells, median frequency 12% (range 2-28%) and 6% (range 2-20%), respectively. Further, the DP T cell subset composition was variable but balanced between central (Tcm) and effector memory (Tem) phenotypes. CAR+ T cells expanded reaching a median peak concentration (C max of 730 cells/µL; range 3-13805 cells/µL) in blood between days 12-14 post-infusion and persisted in circulation for a median of 100 days (range 20-912 days). High efficacy (best response) and DOR were achieved despite variable CAR-T cell expansion and lack of detectable CAR-T cell persistence over time. At C max, the CD4:CD8 ratio (based on % of CAR+ cells) was 0.29, demonstrating a CAR+CD8+ T cell preferential expansion, and both CAR+CD4+ and CAR+CD8+ T cells were predominantly of a Tcm phenotype, median 95% (range 62-99.5%) and 96% (range 33-99.7%), respectively. Higher frequency of early-memory T cell phenotypes has been associated with clinical responses to CAR-T therapies in MM (Dancy et al., Blood 2018). CITE-seq analyses showed that DP characteristics such as a high CD8+ stem-like phenotype and a low CD4+ Treg-like phenotype in the CAR+ T cell compartment associated with longer DOR. Some of the most abundant clones in the DP single cell TCR data were CAR+CD8+ T cells expressing granzyme B, suggesting high cytotoxic potential. Additional bulk TCR sequencing data suggest both diversity and individual clonal expansion longitudinally after cilta-cel infusion. We also evaluated tumor and patient intrinsic characteristics at baseline. BCMA expression on bone marrow PC was prevalent and highly variable among RRMM patients; however, expression did not associate with best response or DOR. Further, high ORR was observed in patients with high-risk cytogenetics, high tumor burden (>= 60% bone marrow PC), or baseline plasmacytomas, although with a non-statistically significant shorter PFS. Sustained MRD negativity strongly associated with longer DOR. Conversely, patient-intrinsic characteristics associated with inflammation (CRP, ferritin, neutrophils, pro-inflammatory cytokines) correlated with shorter DOR. Treatment benefit of the magnitude seen with cilta-cel had not been reported with any other approved therapy in this setting. Correlative analyses suggest an emerging profile to help understand such outstanding clinical activity: a balanced CD4/CD8 ratio and Tcm/Tem phenotype of the manufactured DP and preferential expansion of CAR+CD8+ Tcm cells. Further, certain baseline patient-intrinsic and tumor characteristics may explain the longer DOR in the RRMM setting. These investigations help identify markers of response to cilta-cel and may lead to CAR-T cell design or manufacturing strategies that enhance drug product characteristics and thus clinical efficacy.

8009 Background: Heavily pretreated patients (pts) with relapsed/refractory multiple myeloma (RRMM) treated with standard of care therapy have median overall survival (OS) of ~12 months (mo). In the single-arm, phase 1b/2 CARTITUDE-1 study (NCT03548207), pts received a single infusion of ciltacabtagene autoleucel (cilta-cel), a CAR-T cell therapy targeting BCMA. At the final protocol-specified analysis (27.7-mo median follow-up [MFU]), overall response rate (ORR) was 98%, with 83% stringent complete response (CR); 27-mo rates of progression-free survival (PFS) and OS were 55% and 70%, respectively. Here, we report study closeout results. Methods: Eligible pts received ≥3 prior lines of therapy (LOT) or were double refractory to a proteasome inhibitor (PI) and immunomodulatory drug (IMiD); and had received prior PI, IMiD, and anti-CD38 antibody therapy. Primary endpoint was ORR and safety; secondary endpoints included PFS, OS, and minimal residual disease (MRD) negativity at 10-5. Results: 97 pts received cilta-cel (median age 61 years [y]; median 6 prior LOT; 42% penta-drug refractory; 88% triple-class refractory; 99% refractory to last LOT). As of October 14, 2022, MFU was 33.4 mo (range, 1.5-45.2). Median (m) duration of response was 33.9 mo (95% CI, 25.5–not estimable [NE]). mPFS was 34.9 mo (95% CI, 25.2–NE), with an estimated 47.5% progression free and alive at 36 mo. mOS was not reached (NR), with an estimated 62.9% survival at 36 mo. Of 49 MRD-evaluable pts, 26 had MRD negativity sustained for ≥12 mo, of which 20 had sustained MRD-negative ≥CR. mPFS was NR in these subgroups (Table). 18 pts were MRD negative with ≥CR at 24 mo post infusion. No new safety signals and no new neurotoxicity events were reported since the 27.7-mo MFU. 6 new cases of second primary malignancy were reported, including 2 cases of basal cell carcinoma and 1 case each of myelodysplastic syndrome, B-cell lymphoma, melanoma, and prostate cancer. 5 additional deaths occurred (progressive disease [PD], n=3; pneumonia and sepsis, n=1 each [both unrelated to cilta-cel]), for a total of 35 (PD, n=17; unrelated to cilta-cel, n=12; related, n=6). Conclusions: Longer mPFS was observed after a single infusion of cilta-cel than any previously reported therapy in heavily pretreated pts with RRMM. Achieving CR and/or sustained MRD negativity was associated with prolonged PFS. Pts continue to be followed for safety and survival in the 15-y CARTINUE long-term study (NCT05201781; MMY4002). Clinical trial information: NCT03548207 . [Table: see text]

8028 Background: Ciltacabtagene autoleucel (cilta-cel), a chimeric antigen receptor T (CAR-T) cell therapy with 2 B-cell maturation antigen (BCMA)–targeting single-domain antibodies, led to early, deep, and durable responses in the phase 1b/2 CARTITUDE-1 study (NCT03548207) in heavily pretreated patients (pts) with relapsed/refractory multiple myeloma (RRMM). At ̃1-year (y) median follow-up (MFU), overall response rate (ORR) was 97%; 67% of pts achieved stringent complete response (sCR). 1-y progression-free survival (PFS) and overall survival (OS) rates were 77% and 89%, respectively (Berdeja 2021). Updated results 2-y post last patient in (LPI) will be presented (̃30-month total MFU). Here, we report CARTITUDE-1 results at 21.7-month MFU. Methods: Eligible pts with RRMM received ≥3 prior lines of therapy (LOT) or were refractory to a proteasome inhibitor (PI) and immunomodulatory drug (IMiD) and had received a PI, IMiD, and anti-CD38 antibody. Bridging therapy was permitted after apheresis. Pts received a single cilta-cel infusion (target dose 0.75×106 CAR+ viable T cells/kg) 5–7 days after lymphodepletion. Primary objectives were to evaluate cilta-cel safety and efficacy. Response was assessed per International Myeloma Working Group criteria by independent review committee and minimal residual disease (MRD) negativity at 10-5 by next-generation sequencing. Results: As of July 22, 2021, 97 pts (59% male; median age 61 y) received cilta-cel. Pts had a median of 6 (range 3–18) prior LOT; 84% were penta-drug exposed, 88% were triple-class refractory, 42% were penta-drug refractory, and 99% were refractory to last LOT. ORR was 97.9% (95% CI 92.7–99.7), 94.9% achieved very good partial response, and 82.5% achieved sCR. Median times to first response, best response, and ≥CR were 1.0, 2.6, and 2.9 months (m), respectively; median duration of response was not reached (NR). Of 61 pts evaluable for MRD, 92% were MRD negative (10-5), sustained for ≥6 m in 44% (27/61) and ≥12 m in 18% (11/61). 2-y PFS was 60.5% (95% CI 48.5–70.4). Median PFS and OS were NR. 2-y PFS rates in pts with sustained MRD negativity for ≥6 m and ≥12 m were 91% and 100%, respectively. There were no new safety signals or new events of CAR-T cell neurotoxicity, movement and neurocognitive treatment-emergent adverse events, or treatment-related deaths since 1-y MFU. 15 second primary malignancies were reported in 11 pts over ̃2-y MFU. Conclusions: At ̃2-y MFU, a single cilta-cel infusion led to deepening and durable responses in heavily pretreated pts with RRMM with a manageable safety profile. Follow-up is ongoing, and landmark 2-y post LPI data (̃8 m additional follow-up; ̃30 m total MFU) will be presented. Further investigations of cilta-cel are ongoing in earlier LOT and outpatient settings across the CARTITUDE program (NCT04133636, NCT04181827, NCT04923893). Clinical trial information: NCT03548207.

PURPOSE CARTITUDE-1, a phase Ib/II study evaluating the safety and efficacy of ciltacabtagene autoleucel (cilta-cel) in heavily pretreated patients with relapsed/refractory multiple myeloma, yielded early, deep, and durable responses at 12 months. Here, we present updated results 2 years after last patient in (median follow-up [MFU] approximately 28 months), including analyses of high-risk patient subgroups. METHODS Eligible patients had relapsed/refractory multiple myeloma, had received ≥ 3 prior lines of therapy or were double refractory to a proteasome inhibitor and immunomodulatory drug and had received prior proteasome inhibitor, immunomodulatory drug, and anti-CD38 therapy. Patients received a single cilta-cel infusion 5-7 days after lymphodepletion. Responses were assessed by an independent review committee. RESULTS At a MFU of 27.7 months (N = 97), the overall response rate was 97.9% (95% CI, 92.7 to 99.7); 82.5% (95% CI, 73.4 to 89.4) of patients achieved a stringent complete response. Median duration of response was not estimable. Median progression-free survival (PFS) and overall survival (OS) were not reached; 27-month PFS and OS rates were 54.9% (95% CI, 44.0 to 64.6) and 70.4% (95% CI, 60.1 to 78.6), respectively. Overall response rates were high across all subgroups (95.1%-100%). Duration of response, PFS, and/or OS were shorter in patients with high-risk cytogenetics, International Staging System stage III, high tumor burden, or plasmacytomas. The safety profile was manageable with no new cilta-cel–related cytokine release syndrome and one new case of parkinsonism (day 914 after cilta-cel) since the last report. CONCLUSION At approximately 28 months MFU, patients treated with cilta-cel maintained deep and durable responses, observed in both standard and high-risk subgroups. The risk/benefit profile of cilta-cel remained favorable with longer follow-up.

Abstract Introduction: Ciltacabtagene autoleucel (cilta-cel), a chimeric antigen receptor T (CAR-T) cell therapy with 2 B-cell maturation antigen (BCMA) targeting single-domain antibodies, demonstrated early, deep, and durable responses in the phase 1b/2 CARTITUDE-1 study in patients (pts) with relapsed/refractory multiple myeloma (RRMM) who had been heavily pretreated (Berdeja, Lancet, 2021). After a median follow-up of 12.4 months, the overall response rate (ORR; as assessed by independent review committee) was 97%, with 67% of pts achieving stringent complete response (sCR). The 12-month progression-free survival (PFS) and overall survival (OS) rates were 77% and 89%, respectively. Here, we report updated results from CARTITUDE-1 with longer duration of follow-up (median 18 months). Methods: Eligible pts had MM and received ≥3 prior therapies or were refractory to a proteasome inhibitor (PI) and an immunomodulatory drug (IMiD), and had received a PI, IMiD, and an anti-CD38 antibody. After apheresis, bridging therapy was permitted. Pts received a single cilta-cel infusion (target dose 0.75×10 6 CAR+ viable T cells/kg; range 0.5-1.0×10 6) 5-7 days (d) after lymphodepletion (300 mg/m 2 cyclophosphamide, 30 mg/m 2 fludarabine daily for 3 d). Primary objectives were to characterize cilta-cel safety, confirm the recommended phase 2 dose (phase 1b), and evaluate cilta-cel efficacy (phase 2). Response was assessed per IMWG criteria by an independent review committee and minimal residual disease (MRD) negativity at 10 -5 by next-generation sequencing. In this combined phase 1b and phase 2 analysis, cytokine release syndrome (CRS; per Lee et al Blood 2014 grading criteria) and neurotoxicity (by CTCAE v5.0) were mapped to the ASTCT criteria for CRS and immune effector cell-associated neurotoxicity (ICANS), respectively. Results: As of Feb 11, 2021, 97 pts (58.8% male; median age 61.0 years [range 43-78]) received cilta-cel. Pts had received a median of 6 (range 3-18) prior lines of therapy; 83.5% were penta-drug exposed, 87.6% were triple-class refractory, 42.3% were penta-drug refractory, and 99.0% were refractory to last line of therapy. ORR was 97.9% (95% CI: 92.7-99.7); 80.4% of pts achieved sCR, and 94.8% achieved very good partial response or better (Figure). The median time to first response was 1 month (range 0.9-10.7), median time to best response was 2.6 months (range 0.9-15.2), and median time to complete response or better was 2.6 months (range 0.9-15.2). The median duration of response was 21.8 months (95% CI: 21.8-not estimable). Of 61 pts evaluable for MRD, 91.8% were MRD negative at the 10 -5 threshold; MRD 10 -5 negativity was sustained for ≥6 months in 44.3% (27/61) of pts and ≥12 months in 18% (11/61) of pts. The 18-month PFS and OS rates were 66.0% (95% CI: 54.9-75.0) and 80.9% (95% CI: 71.4-87.6), respectively. 18-month PFS rates in pts who achieved sustained MRD for ≥6 months and ≥12 months were 96.3% (95% CI: 76.5-99.5) and 100%, respectively. The most common grade 3/4 hematologic AEs in ≥25% of pts were neutropenia (94.8%), anemia (68.0%), leukopenia (60.8%), thrombocytopenia (59.8%), and lymphopenia (49.5%). There were no fatalities related to cytopenias, and no new safety signals with longer follow-up. CRS occurred in 94.8% of pts (mostly grade 1/2); median time to onset was 7 d (range 1-12), and CRS resolved within 14 d in 98.9% of pts. There was no new CAR T-cell neurotoxicity since the previous report. Post cilta-cel infusion, 21 deaths occurred during the study: 0 within first 30 d, 2 within 100 d, and 19 more than 100 d post infusion. Ten deaths were due to disease progression, 6 were treatment-related (as assessed by the investigator), and 5 were due to AEs unrelated to treatment. One patient was retreated with cilta-cel (for progressive disease) and had stable disease (per computerized algorithm) post-retreatment with no incidence of CAR T-cell neurotoxicity. Conclusions: At a longer median follow-up of 18 months, a single cilta-cel infusion led to early, deep, and durable responses in heavily pre-treated pts with MM. Follow-up is ongoing and updated data will be presented. Cilta-cel demonstrated a manageable safety profile with no new safety signals observed with longer follow-up. Further investigations of cilta-cel are ongoing in earlier lines of therapy (CARTITUDE-2 [NCT04133636], CARTITUDE-4 [NCT04181827], and CARTITUDE-5 [NCT04923893]) and in outpatient settings. Figure 1 Figure 1. Disclosures Martin: GlaxoSmithKline: Consultancy; Janssen: Research Funding; Sanofi: Research Funding; Amgen: Research Funding. Usmani: Takeda: Consultancy, Research Funding, Speakers Bureau; SkylineDX: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Merck: Consultancy, Research Funding; Janssen Oncology: Consultancy, Research Funding; Bristol-Myers Squibb: Research Funding; EdoPharma: Consultancy; Array BioPharma: Consultancy, Research Funding; Celgene/BMS: Consultancy, Research Funding, Speakers Bureau; GSK: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding, Speakers Bureau; Janssen: Consultancy, Research Funding, Speakers Bureau; Amgen: Consultancy, Research Funding, Speakers Bureau; Abbvie: Consultancy. Berdeja: Lilly, Novartis: Research Funding; Poseida, Sanofi, Teva: Research Funding; GSK, Ichnos Sciences, Incyte: Research Funding; Bluebird bio, BMS, Celgene, CRISPR Therapeutics, Janssen, Kite Pharma, Legend Biotech, SecuraBio, Takeda: Consultancy; Celularity, CRISPR Therapeutics: Research Funding; Abbvie, Acetylon, Amgen: Research Funding; EMD Sorono, Genentech: Research Funding. Jakubowiak: Amgen: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Gracell: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Cohen: Novartis: Research Funding; BMS/Celgene: Consultancy; Takeda: Consultancy; Genentech/Roche: Consultancy; Oncopeptides: Consultancy; AstraZeneca: Consultancy; Janssen: Consultancy; GlaxoSmithKline: Consultancy, Research Funding. Hari: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding, Speakers Bureau; Karyopharm: Consultancy; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Millenium: Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding, Speakers Bureau; Adaptive Biotech: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding, Speakers Bureau; Celgene-BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding, Speakers Bureau. Avigan: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Kite Pharma: Consultancy, Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees; Partner Tx: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Aviv MedTech Ltd: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Legend Biotech: Membership on an entity's Board of Directors or advisory committees; Chugai: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; Parexcel: Consultancy; Takeda: Consultancy; Sanofi: Consultancy. Deol: Kite, a Gilead Company: Consultancy. Lesokhin: bristol myers squibb: Research Funding; Iteos: Consultancy; pfizer: Consultancy, Research Funding; Behringer Ingelheim: Honoraria; Trillium Therapeutics: Consultancy; Serametrix, Inc: Patents & Royalties; Genetech: Research Funding; Janssen: Honoraria, Research Funding. Munshi: Adaptive Biotechnology: Consultancy; Karyopharm: Consultancy; Oncopep: Consultancy, Current equity holder in publicly-traded company, Other: scientific founder, Patents & Royalties; Legend: Consultancy; Novartis: Consultancy; Abbvie: Consultancy; Celgene: Consultancy; Janssen: Consultancy; Takeda: Consultancy; Amgen: Consultancy; Pfizer: Consultancy; Bristol-Myers Squibb: Consultancy. O'Donnell: Onocopeptide: Consultancy; Karyopharm: Consultancy; Janssen: Consultancy; Bristol Myer Squibb: Consultancy; Adaptive: Consultancy; Takeda: Consultancy. Stewart: Oncopeptides: Honoraria; Janssen: Honoraria; GSK: Honoraria; BMS: Honoraria; Amgen: Honoraria; Skyline diagnostics: Consultancy; Genomcs England: Membership on an entity's Board of Directors or advisory committees; Tempus Inc.: Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees; PikSci Inc.: Current holder of individual stocks in a privately-held company, Patents & Royalties; Sanofi Aventis: Honoraria. Schecter: Janssen: Current Employment, Current holder of stock options in a privately-held company. Goldberg: Janssen: Current Employment, Current holder of individual stocks in a privately-held company. Jackson: Janssen: Current Employment; Memorial Sloan Kettering Cancer Center: Consultancy. Yeh: Janssen: Current Employment. Banerjee: Janssen: Current Employment, Current holder of individual stocks in a privately-held company. Allred: Janssen: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Zudaire: Janssen: Current Employment. Deraedt: Janssen: Current Employment. Olyslager: Janssen: Current Employment. Pacaud: Legend Biotech: Current Employment. Lin: Juno: Consultancy; Bluebird Bio: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy; Takeda: Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Vineti: Consultancy; Gamida Cell: Consultancy; Sorrento: Consultancy; Legend: Consultancy; Merck: Research Funding; Janssen: Consultancy, Research Funding. Jagannath: Legend Biotech: Consultancy; Karyopharm Therapeutics: Consultancy; Janssen Pharmaceuticals: Consultancy; Bristol Myers Squibb: Consultancy; Sanofi: Consultancy; Takeda: Consultancy. OffLabel Disclosure: At the time of abstract submission, cilta-cel is being investigated for the treatment of multiple myeloma but is not yet approved.

Abstract Introduction: Cytokine release syndrome (CRS) is a common toxicity associated with chimeric antigen receptor (CAR) T-cell therapies. Corticosteroids and steroid-sparing therapies such as tocilizumab, an interleukin-6 receptor antagonist, and anakinra, an interleukin-1 receptor antagonist, have been used to reduce the incidence and severity of these toxicities. Preclinical and clinical case studies of anakinra, administered subcutaneously or intravenously at various doses, have shown promising results in the management of CRS and systemic inflammatory responses resembling hemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS). In CARTITUDE-1, CRS occurred in 95% of heavily pretreated patients with relapsed/refractory multiple myeloma (RRMM) receiving ciltacabtagene autoleucel (cilta-cel), a CAR T-cell therapy with 2 B-cell maturation antigen-targeting single-domain antibodies (Berdeja et al. Lancet 2021). Per protocol, tocilizumab was required to manage CRS with option to give steroids and/or anakinra per investigator discretion. Here, we report the institutional experiences of anakinra use in the management of CRS in patients who have received cilta-cel as part of the CARTITUDE-1 study. Methods: Eligible patients had MM and received ≥3 prior therapies or were refractory to a proteasome inhibitor (PI) and immunomodulatory drug (IMiD), and had received a PI, IMiD, and anti-CD38 antibody (Berdeja et al. Lancet 2021). After apheresis, bridging therapy was permitted. Patients received a single cilta-cel infusion (target dose: 0.75×10 6 CAR+ viable T cells/kg; range 0.5-1.0×10 6) 5-7 days after lymphodepletion (300 mg/m 2 cyclophosphamide, 30 mg/m 2 fludarabine daily for 3 days). Lee et al (Blood 2014) grading criteria for CRS were mapped to the ASTCT criteria for CRS. Post-hoc analysis of data revealed use of anakinra at some sites in patients who failed to respond to the initial management of CRS with tocilizumab +/- dexamethasone or in clinical settings where rise of ferritin and/or liver function tests were indicative for continued HLH/MAS-like manifestations (Kennedy et al. ASH 2020). Results: Of 97 patients in CARTITUDE-1, CRS occurred in 92 (95%) patients; 4% were grade 3/4. The median time to onset was 7 days (range 1-12) and median duration was 4 days (range 1-14). Supportive measures to treat CRS were administered to 91% of patients, most commonly tocilizumab (69%; 4 patients received ≥3 doses), corticosteroids (22%), and anakinra (18 patients, 19%). CRS resolved in 99% of patients. Anakinra was administered after initial tocilizumab and within the first 48 hours (range 0-6 days) of CRS onset for the majority of patients as part of effective management of CRS. Anakinra was administered at a dose of 100-200 mg every 8-12 hours over a median of 2.5 days (range 1-15 days). CRS uniformly resolved following anakinra use in CARTITUDE-1, apart from one patient who died from sepsis (grade 5 outcome) due to HLH/MAS considered related to treatment (Table). Conclusions: CRS events in cilta-cel-treated patients in CARTITUDE-1 were common, generally low-grade, and successfully managed with standard tocilizumab +/- dexamethasone. The use of anakinra should be considered in patients with persistent CRS/inflammatory symptoms despite tocilizumab use, and in particular in patients with HLH/MAS-like symptoms/phenotype occurring following CRS or in the absence of prior CRS. Figure 1 Figure 1. Disclosures Wong: Amgen: Consultancy; Genentech: Research Funding; Fortis: Research Funding; Janssen: Research Funding; GloxoSmithKlein: Research Funding; Dren Biosciences: Consultancy; Caelum: Research Funding; BMS: Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees. Richard: Karyopharm, Janssen: Honoraria. Lin: Juno: Consultancy; Legend: Consultancy; Merck: Research Funding; Bluebird Bio: Consultancy, Research Funding; Sorrento: Consultancy; Janssen: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Novartis: Consultancy; Celgene: Consultancy, Research Funding; Takeda: Research Funding; Gamida Cell: Consultancy; Vineti: Consultancy. Madduri: Janssen: Current Employment. Jackson: Janssen: Current Employment; Memorial Sloan Kettering Cancer Center: Consultancy. Zudaire: Janssen: Current Employment. Romanov: Janssen: Current Employment. Trigg: Janssen: Current Employment. Vogel: Janssen Global Services, LLC: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company, Divested equity in a private or publicly-traded company in the past 24 months. Garrett: Legend Biotech USA: Current Employment. Nesheiwat: Legend Biotech USA: Current Employment. Martin: Oncopeptides: Consultancy; Sanofi: Research Funding; Janssen: Research Funding; GlaxoSmithKline: Consultancy; Amgen: Research Funding. Jagannath: Bristol Myers Squibb: Consultancy; Legend Biotech: Consultancy; Karyopharm Therapeutics: Consultancy; Janssen Pharmaceuticals: Consultancy; Takeda: Consultancy; Sanofi: Consultancy. OffLabel Disclosure: At the time of abstract submission, cilta-cel is being investigated for the treatment of multiple myeloma but is not yet approved

Abstract Introduction: Ciltacabtagene autoleucel (cilta-cel), a chimeric antigen receptor T-cell (CAR-T) therapy with 2 B-cell maturation antigen (BCMA)-targeting single-domain antibodies, is being evaluated in patients (pts) with relapsed/refractory multiple myeloma (RRMM). In the phase 1b/2 CARTITUDE-1 (NCT03548207) study, a single dose of cilta-cel led to early, deep, and durable responses in heavily pretreated pts with MM, with a manageable safety profile (Berdeja, Lancet, 2021). At median 18 months of follow-up, the overall response rate (ORR) was 98%, with 80% of pts achieving stringent complete response. Median duration of response (DOR) was 21.8 months (95% CI, 21.8-not estimable); 18-month progression-free survival (PFS) and overall survival (OS) rates were 66% and 81%, respectively. Here, we report the efficacy and safety of cilta-cel in various subgroups of pts in CARTITUDE-1. Methods: Eligible pts had MM and received ≥3 prior lines of therapy (LOT) or were double refractory to a proteasome inhibitor (PI) and immunomodulatory drug (IMiD), and had received a PI, IMiD, and anti-CD38 antibody. After apheresis, bridging therapy was permitted. Pts received a single cilta-cel infusion (target dose: 0.75×10 6 CAR+ viable T cells/kg; range 0.5-1.0×10 6) 5-7 days after lymphodepletion (300 mg/m 2 cyclophosphamide, 30 mg/m 2 fludarabine daily for 3 days). Primary objectives were to characterize cilta-cel safety, confirm the recommended phase 2 dose (phase 1b), and evaluate efficacy (phase 2). In this combined phase 1b and phase 2 analysis, cytokine release syndrome (CRS) graded by Lee et al (Blood 2014) criteria and neurotoxicity by CTCAE v5.0 were mapped to the ASTCT criteria for CRS and immune effector cell-associated neurotoxicity (ICANS), respectively. Efficacy and safety were evaluated in the following subgroups: ≥65 years of age, Black/African American, 3 prior LOT, ≥4 prior LOT, triple-class refractory, penta-drug refractory, standard- and high-risk cytogenetics, International Staging System stage III, bone marrow plasma cells at baseline (≤30%, >30 to <60%, and ≥60%), BCMA tumor expression at baseline (<80%, ≥80%), and presence of soft tissue plasmacytomas (bone-based and extramedullary). Results: As of February 11, 2021, 97 pts in the overall population received cilta-cel; 58.8% were male, median age was 61 years (range 43-78), and median time from diagnosis to enrollment was 5.9 years (range 1.6-18.2). ORR across all evaluated subgroups was comparable to the overall population, and was consistently high (range 95.1-100%) including in those with high-risk cytogenetics, ISS stage III MM, baseline bone marrow cells ≥60%, and baseline plasmacytomas (Table). Median DOR for most subgroups, including high-risk cytogenetics, was consistent with the overall population or not reached but was shorter in pts with ISS Stage III MM and baseline plasmacytomas (Table). Across all subgroups, 80%-100% of MRD-evaluable pts achieved MRD negativity (10 -5 threshold). 18-month PFS and OS rates were consistent with the overall population in most subgroups, including high-risk cytogenetics, and lower in ISS stage III and baseline plasmacytomas (Table). Incidence of CRS, ICANS, and other CAR T-cell neurotoxicities (events not reported as ICANS [ie, onset after a period of recovery from CRS and ICANS]) in various subgroups was consistent with the overall population, with no new safety signals. Conclusions: At median follow-up of 18 months, a single infusion of cilta-cel yielded deep, durable responses in all evaluated subgroups in CARTITUDE-1. An ORR of 95%-100% was observed in pts across all subgroups, including those with high-risk cytogenetics, ISS stage III MM, baseline bone marrow cells ≥60%, and baseline plasmacytomas. In patients with ISS stage III and with baseline plasmacytomas, median DOR appeared shorter and 18-mo PFS and OS rates lower. Cilta-cel safety profile across the subgroups was consistent with the overall population, with no new safety signals. Ongoing evaluation of cilta-cel in the multicohort CARTITUDE-2 (NCT04133636) study in pts with unmet need in varying stages of treatment for MM will further explore the treatment benefit of cilta-cel, including in those with high-risk disease. Figure 1 Figure 1. Disclosures Jakubowiak: GSK: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Gracell: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Usmani: Janssen Oncology: Consultancy, Research Funding; Takeda: Consultancy, Research Funding, Speakers Bureau; SkylineDX: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding, Speakers Bureau; Amgen: Consultancy, Research Funding, Speakers Bureau; Merck: Consultancy, Research Funding; Janssen: Consultancy, Research Funding, Speakers Bureau; Array BioPharma: Consultancy, Research Funding; GSK: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Celgene/BMS: Consultancy, Research Funding, Speakers Bureau; EdoPharma: Consultancy; Abbvie: Consultancy; Bristol-Myers Squibb: Research Funding. Berdeja: Bluebird bio, BMS, Celgene, CRISPR Therapeutics, Janssen, Kite Pharma, Legend Biotech, SecuraBio, Takeda: Consultancy; GSK, Ichnos Sciences, Incyte: Research Funding; EMD Sorono, Genentech: Research Funding; Celularity, CRISPR Therapeutics: Research Funding; Lilly, Novartis: Research Funding; Abbvie, Acetylon, Amgen: Research Funding; Poseida, Sanofi, Teva: Research Funding. Cohen: Oncopeptides: Consultancy; Genentech/Roche: Consultancy; Janssen: Consultancy; BMS/Celgene: Consultancy; Takeda: Consultancy; GlaxoSmithKline: Consultancy, Research Funding; AstraZeneca: Consultancy; Novartis: Research Funding. Hari: Karyopharm: Consultancy; Adaptive Biotech: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Millenium: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding, Speakers Bureau; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding, Speakers Bureau; Celgene-BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding, Speakers Bureau; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding, Speakers Bureau; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Schecter: Janssen: Current Employment, Current holder of stock options in a privately-held company. Yeh: Janssen: Current Employment. Olyslager: Janssen: Current Employment. Banerjee: Janssen: Current Employment, Current holder of individual stocks in a privately-held company. Jackson: Janssen: Current Employment; Memorial Sloan Kettering Cancer Center: Consultancy. Allred: Janssen: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Zudaire: Janssen: Current Employment. Deraedt: Janssen: Current Employment. Geng: Legend Biotech USA: Current Employment. Pacaud: Legend Biotech: Current Employment. Lin: Janssen: Consultancy, Research Funding; Vineti: Consultancy; Legend: Consultancy; Bluebird Bio: Consultancy, Research Funding; Novartis: Consultancy; Juno: Consultancy; Celgene: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Takeda: Research Funding; Sorrento: Consultancy; Merck: Research Funding; Gamida Cell: Consultancy. Martin: Janssen: Research Funding; GlaxoSmithKline: Consultancy; Oncopeptides: Consultancy; Amgen: Research Funding; Sanofi: Research Funding. Jagannath: Bristol Myers Squibb: Consultancy; Janssen Pharmaceuticals: Consultancy; Legend Biotech: Consultancy; Karyopharm Therapeutics: Consultancy; Takeda: Consultancy; Sanofi: Consultancy. OffLabel Disclosure: At the time of abstract submission, cilta-cel is being investigated for the treatment of multiple myeloma but is not yet approved.