Htut, Myo

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.

e20021 Background: CAR T cell therapies are FDA approved for patients with triple refractory multiple myeloma (MM) and >4 lines of therapy. The median survival of this is group is less than 12 months so salvage therapies need to be implemented quickly. Real-world access to CAR T remains challenging due to supply chain limitations impacting manufacturing. The goal of this study was to evaluate how centers are handling the challenges of CAR T slot allocation. Methods: MM CAR T physician leaders at each CAR T treatment center certified for idecabtagene vicleucel across the US were surveyed. Results: We received responses from 15/20 centers. Summary of CAR T volumes and outcomes of patient on waitlists are shown in the table. The median time on the waiting list was 6 months with only 25% of patients receiving CAR T eventually. For patient selection, all centers reported using a committee of experienced CART physicians to ensure consistency. Selection committee included: primary MD (n=9), CAR T MD (n=12), social workers (n=3), CAR T RN (n=10), APP (n=2), pharmacists (n=2) and ethicists (n=1). To ensure transparency, centers have clear selection criteria (n=10), priority score (n=8) and selection timeline (n=11) . To ensure accountability, centers document priority scores (n=5) and have pre-specified criteria (n=9) for selection. Centers also reported using ethical principles for selection: a) equal treatment: time spent on waiting list (n=8); b) priority to the worst-off: limited therapeutic options (n=10), MM burden (n=7), ineligible for trials (n=2); c) maximize benefit: most likely to complete apheresis (n=8) or infusion (n=8) or achieve response (n=6) and d) social value: younger pts (n=2). Maximizing benefit was considered the most important criterion by 7 centers. Conclusions: More stringent GMP manufacturing requirements with FDA approved CAR T and real-world practice with broader patient demographics can present challenges to implementation of CAR T in standard of practice. Our study is the first attempt to evaluate and highlight existing issues with MM CAR T access and the variability and challenges in patient selection. Learning from other models of resource allocation (ex: UNOS) and sharing experience across centers can help providers optimize slot allocation to improve accrual. Increasing supplies of key reagents and novel manufacturing methods(eg: non-viral vectors and allogeneic CAR) could help overcome these limitations. [Table: see text]

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.

The NCCN Guidelines for Multiple Myeloma provide recommendations for diagnosis, initial workup, treatment, follow-up, and supportive care for patients with various plasma cell neoplasms, including multiple myeloma. These NCCN Guidelines Insights highlight some of the important updates/changes specific to the treatment of patients with multiple myeloma in the 2022 version of the guidelines.

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 Background Allogeneic (off the shelf) chimeric antigen receptor (CAR) T-cell therapy addresses the logistical challenges, availability (including insufficient T-cell yields from low baseline absolute lymphocyte count), and variable product quality of autologous CAR T therapy. ALLO-715 is a genetically modified anti-BCMA AlloCAR T™ cell which uses Cellectis TALEN ® technology to disrupt the T-cell receptor alpha constant gene (TRAC) and the CD52 gene to reduce the risk of graft-versus-host disease (GvHD) and permit the use of ALLO-647, an anti-CD52 monoclonal antibody (mAb), for selective and transitory host lymphodepletion (LD). Methods UNIVERSAL is an open-label, Phase 1 trial (NCT04093596) in adults with relapsed/refractory (R/R) multiple myeloma who have received ≥3 prior lines of therapy including a proteasome inhibitor, immunomodulator, and anti-CD38 mAb. Patients (pts) must be refractory to their last treatment line. Pts receive LD followed by ALLO-715 at 1 of 4 dose levels (DLs) in a 3+3 dose escalation design: 40, 160, 320, and 480 x 10 6 CAR+ T cells. Several LD regimens are being evaluated: FCA39; FCA60; FCA90; and CA39; with fludarabine [F] 90 mg/m 2, cyclophosphamide [C] 900 mg/m 2, and ALLO-647 [A] 39, 60, or 90 mg divided over 3 days. Results As of June 21, 2021 data-cut, 47 subjects were enrolled; 42 were treated with ALLO-715; 5 progressed prior to treatment. Median time from enrollment to LD was 5 days and no treated pts required bridging therapy. Pts were heavily pretreated with a range of 3-11 prior lines of therapy; 42.9% were penta refractory. There were 19% ISS Stage III at screening, 34% had high risk cytogenetics, and 19% had extramedullary disease. The most common Grade (Gr) 3+ adverse events (AEs) included anemia, neutropenia, lymphopenia, and thrombocytopenia. Cytokine release syndrome (CRS) occurred in 52.4%, all Gr 1/2 except 1 pt with Gr 3. CRS was treated with tocilizumab (21.3%) and corticosteroids (12.8%). One pt (with Gr 2 CRS) experienced Gr 1 neurotoxicity that resolved. Gr 3+ infections occurred in 12.8% of pts, including 2 previously reported Gr 5 events (fungal pneumonia and adenovirus hepatitis). Early results from this trial have been presented previously (ASH 2020) and therefore the efficacy analysis on pts (n=26) treated at DL3 and DL4 with FCA LD, which are considered a more relevant cell dose and LD, is presented here (Table). In pts who received DL3 or DL4 (320 or 480 x 10 6 CAR T cells) (n=26), the ORR was 61.5% (95% CI: 40.6, 79.8); very good partial response or better (VGPR+) rate was 38.5% (95% CI: 20.2, 59.4). Median time to 1 st response was 16 days. The median follow-up for the DL3/DL4 pts was 7.4 months (95% CI: 3.6, 9.9) with a median duration of response of 8.3 months (95% CI: 1.5, not reached). Of the 10 pts with a best response of VGPR+, 8 were found to be negative by minimal residual disease (MRD) analysis. Conclusions UNIVERSAL demonstrates proof of concept for allogeneic CAR T therapy in multiple myeloma. ALLO-715 showed CAR T cell dose response relationship with higher doses (DL3/DL4) leading to clinically meaningful efficacy, including high VGPR+ rate of 38.5% and high MRD negativity without requiring leukapheresis or bridging therapy. ALLO-715 following LD with FCA has a tolerable safety profile. FCA induces a deep and durable window of lymphocyte depletion allowing CAR T cell expansion and persistence. A study using the next generation anti-BCMA CAR (ALLO-605) which supplies cytokine signaling to the CAR bearing cells is ongoing (IGNITE). The current UNIVERSAL trial continues to enroll, including a cohort with consolidation, and updated data will be presented at the meeting. Figure 1 Figure 1. Disclosures Mailankody: Allogene Therapeutics: Research Funding; Plexus Communications: Honoraria; Fate Therapeutics: Research Funding; Physician Education Resource: Honoraria; Bristol Myers Squibb/Juno: Research Funding; Jansen Oncology: Research Funding; Legend Biotech: Consultancy; Evicore: Consultancy; Takeda Oncology: Research Funding. Liedtke: Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees; Kura Oncology: Membership on an entity's Board of Directors or advisory committees; Alnylam: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Caelum: Membership on an entity's Board of Directors or advisory committees, Other: Clinical Trial Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Sidana: BMS: Consultancy; Magenta Therapeutics: Consultancy, Research Funding; Allogene: Research Funding; Janssen: Consultancy, Research Funding. Chhabra: GSK: Honoraria. Oluwole: Janssen: Consultancy; Pfizer: Consultancy; Curio Science: Consultancy; Kite, a Gilead Company: Consultancy, Research Funding. Kumar: Oncopeptides: Consultancy; Antengene: Consultancy, Honoraria; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bluebird Bio: Consultancy; Roche-Genentech: Consultancy, Research Funding; Merck: Research Funding; Carsgen: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Beigene: Consultancy; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Tenebio: Research Funding; Sanofi: Research Funding. Nath: Actinium: Consultancy, Honoraria; Incyte: Consultancy, Honoraria. Anwer: Janssen pharmaceutical: Honoraria, Research Funding; Allogene Therapeutics: Research Funding; GlaxoSmithKline: Research Funding; BMS / Celgene: Honoraria, Research Funding. Raje: Caribou: Other; Janssen: Other; bluebird bio: Other; Amgen: Other; Celgene: Other; BMS: Other. Siegel: Bristol Myers Squibb: Honoraria, Speakers Bureau; Takeda: Honoraria; GlaxoSmithKline: Honoraria, Speakers Bureau; Celularity: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Honoraria; Amgen Inc.: Honoraria; Janssen: Honoraria, Speakers Bureau. Karski: Allogene Therapeutics: Current Employment, Current equity holder in publicly-traded company; Crispr Therapeutics: Current equity holder in publicly-traded company; Nektar Therapeutics: Current equity holder in publicly-traded company. Lovelace: Allogene Therapeutics, Inc.: Current Employment. Lourbakos: Allogene Therapeutics, Inc.: Current Employment. Hari: Millenium: Membership on an entity's Board of Directors or advisory committees, Research Funding; 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; Adaptive Biotech: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; 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; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding, Speakers Bureau; Karyopharm: Consultancy; 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.

2537 Background: Orva-cel is a B-cell maturation antigen–targeted chimeric antigen receptor (CAR) T cell therapy being evaluated in the phase 1/2 EVOLVE study (NCT03430011) in pts with RRMM who had at least 3 prior lines of therapy (Tx). We previously reported safety and efficacy in the phase 1 study and established the recommended dose (RD) of orva-cel as 600 × 106 CAR+ T cells (Mailankody et al, ASCO 2020). Cytokine release syndrome (CRS), a dominant toxicity of CAR T cell therapy, is mediated in part by IL-1. We explore the role of ppx with AKR, an IL-1 signaling inhibitor, on reducing the incidence of grade (G) ≥2 CRS after orva-cel treatment at the RD. Methods: Fourteen pts were enrolled sequentially for AKR ppx and treated with orva-cel at the RD. The non-AKR ppx control group comprised the remainder of the phase 1 pts receiving orva-cel at the RD (n = 19). The median follow-up (range) was 3.0 mo (1.8–6.2) for the AKR ppx group and 8.8 mo (5.3–12.2) for the non-AKR ppx group. AKR was administered as 100 mg SC the night before orva-cel infusion, 3 h before the infusion (Day 1), and q24 h on Days 2–5. Dosing was increased to q12 h if CRS developed. CRS was graded by Lee (2014) criteria. Tocilizumab (T) and steroids (S) were used per protocol-specified treatment management guidelines. Results: Disease characteristics and outcomes are shown in the table. In AKR ppx and non-AKR ppx groups, median number of prior regimens was 6 and 5, and bridging Tx was used in 57% and 68% of pts, respectively. The total frequency of CRS was similar in the 2 groups, but with less G 2 in the AKR ppx pts; relative risk (95% CI) = 0.54 (0.21, 1.38). No G ≥3 CRS was seen in either group. The incidence of neurological events (NE), G ≥3 infection, and macrophage activation syndrome/hemophagocytic lymphohistiocytosis (MAS/HLH) was similar. T and S use was numerically lower with AKR ppx. Orva-cel expansion kinetics were similar in the 2 groups. All pts had a 2-month efficacy assessment, with ORR in 100% of AKR ppx and 95% of non–AKR ppx pts. Conclusions: In this nonrandomized evaluation of AKR ppx with orva-cel treatment, the incidence of G ≥2 CRS was lower in pts receiving AKR ppx. The use of AKR ppx produced no adverse effect on the incidence of NE, infection, or MAS/HLH, nor on orva-cel expansion or disease response. These results warrant further study of AKR ppx in CAR T cell therapy. Clinical trial information: NCT03430011. [Table: see text]

Introduction Multiple myeloma (MM), relapsed or refractory (R/R) to standard of care therapies, represents a treatment indication with a significant unmet clinical need. Transcriptional activation of c-MYC through bromodomain and extra-terminal (BET) proteins contributes to the malignant phenotype of the disease. RO is a novel thienodiazepine, small molecule, non-covalent inhibitor of the BET family of bromodomains. Preclinical studies with BET inhibitors have demonstrated significant single agent in vivo activity in myeloma, accompanied by down-regulation of MYC and MYC target gene expression. We report results of a monotherapy phase 1b study of RO in R/R MM (NCT03068351). Methods Eligible pts with R/R MM included those treated with at least three prior lines of multiple myeloma therapy, including a proteasome inhibitor and an immunomodulatory agent, or who are double-refractory to a proteasome inhibitor and an immunomodulatory agent. Primary refractory myeloma pts were only allowed in the dose escalation portion of the study. In the dose escalation (part I), pts received subcutaneous (SC) escalating doses of RO (0.30-0.65 mg/kg) in a standard 3 + 3 design on days 1 - 14 of 21-day cycles to determine both the maximum tolerated dose (MTD) and recommended dose (RD). In the expansion cohort (part II), pts received RO as monotherapy at the RD level. Primary endpoint was safety (DLT, MTD, RD) and secondary endpoints included evaluation of pharmacodynamics (CD11b expression) and preliminary efficacy assessments based on IMWG criteria. Results Between June 2017 and April 2019, a total of 24 pts were enrolled in the US, the UK and Australia. 13 pts were enrolled in the dose escalation and 11 pts in the expansion part. The median age of pts was 65.5 years (range: 46 - 82 years). The study population was heavily pretreated with a median of 6 (3-9) prior therapies. Pts were refractory to immunomodulatory drugs (63%), proteasome inhibitors (46%), both (46%), or daratumumab (42%). 57 total cycles were administered, with a median of 2 (1-6) cycles per patient (pt). Two DLTs occurred in one pt in the 0.65 mg/kg cohort (thrombocytopenia grade 4, angina pectoris grade 3). The recommended dose is 0.65 mg/kg. Grade 3 treatment emergent AEs in ≥ 5% of pts were thrombocytopenia (11 pts [45.8%]), anemia (7 pts [29.2%]), fatigue (3 pts [12.5%]), injection site reaction, malaise, decreased appetite, and hyponatremia (2 pts [8.3%] each). 3 pts (12.5%) experienced a total of 4 AEs leading to discontinuation of the study treatment; these AEs were left ventricular dysfunction, fatigue, sepsis, and staphylococcal bacteremia (the latter two AEs occurred in the same pt). A total of 8 deaths (33.3%) were reported in the study, all as a consequence of progressive disease. The best overall response recorded was partial response in 4 pts (16.7 %), 3 of whom having received prior daratumumab. One pt experienced a minimal response, and stable disease was reported in 12 out of 24 (50%). There was no evidence for a dose-related increase in efficacy, though data are very limited (Table). Responses obtained during treatment with RO6870810 were short-lived and lasted for appr. 6 weeks. As evidence of target engagement, pharmacodynamic profiling demonstrated decreases in CD11b levels in peripheral blood mononuclear cells (Figure). Conclusions Treatment of MM pts with the BET inhibitor RO as monotherapy resulted in a high incidence of cytopenias, especially grade 3-4 thrombocytopenia and grade 3 anemia. However, none of these events led to study drug discontinuation. Cytopenias are a known side effect of BET inhibitors, with thrombocytopenia frequently reported as a DLT in various pt populations. Pts with NUT carcinoma, other solid tumors, or diffuse large B-cell lymphoma treated in the First in Man trial of RO had a low rate of cytopenias, indicating that the underlying disease and the extensive pre-treatment in MM may play a role in their occurrence (publication submitted). In this heavily pretreated R/R MM population, we have established 0.65 mg/kg as the recommended monotherapy dose. Pharmacodynamics effects were evident at this dose, but as monotherapy in this R/R MM cohort, response rates were low and less durable. Future drug combination approaches may result in an improved benefit / risk ratio. Disclosures Ramasamy: Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; BMS: Consultancy, Research Funding, Speakers Bureau; Takeda: Consultancy, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Oncopeptides: Consultancy, Honoraria. Nooka:Adaptive Technologies: Consultancy, Honoraria; Oncopeptides: Consultancy, Honoraria; Spectrum Pharmaceuticals: Consultancy; GlaxoSmithKline: Consultancy, Honoraria, Other: Personal Fees: Travel/accomodations/expenses, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria; Karyopharm Therapeutics, Adaptive technologies: Consultancy, Honoraria, Research Funding. Quach:Amgen, Celgene, karyopharm, GSK, Janssen Cilag, Sanofi.: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline, Karyopharm, Amgen, Celgene, Janssen Cilag: Consultancy; GlaxoSmithKline, Karyopharm, Amgen, Celgene, Janssen Cilag: Honoraria; Amgen, sanofi, celgene, Karyopharm, GSK: Research Funding. Htut:City of Hope Medical Center: Current Employment. Popat:AbbVie: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Other: Travel support, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria; GSK: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Liedtke:Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Caelum: Membership on an entity's Board of Directors or advisory committees; Adaptive: Membership on an entity's Board of Directors or advisory committees. Tuchman:Caelum: Honoraria; Sanofi: Honoraria, Research Funding; Amgen: Research Funding; Janssen: Research Funding; Oncopeptides: Consultancy; Roche: Research Funding; Karyopharm: Honoraria, Research Funding; Celgene: Honoraria, Research Funding, Speakers Bureau. Hertzberg:Gilead: Membership on an entity's Board of Directors or advisory committees; MSD: Membership on an entity's Board of Directors or advisory committees; Abbvie: Honoraria; BMS: Honoraria; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support of parent study and funding of editorial support. Demario:BioNTech SE: Current Employment, Current equity holder in publicly-traded company; Hoffmann-La Roche Ltd.: Current equity holder in publicly-traded company, Ended employment in the past 24 months. Nueesch:Hoffmann-La Roche Ltd.: Current Employment, Current equity holder in publicly-traded company. Chesne:Hoffmann-La Roche Ltd.: Current Employment, Current equity holder in publicly-traded company. Franjkovic:Hoffmann-La Roche Ltd.: Current Employment, Current equity holder in publicly-traded company. Lechner:Roche Diagnostics GmbH: Current Employment, Current equity holder in publicly-traded company. Kornacker:Hoffmann-La Roche Ltd.: Current Employment, Current equity holder in publicly-traded company.