Orvacabtagene autoleucel (orva-cel), a B-cell maturation antigen (BCMA)-directed CAR T cell therapy for patients (pts) with relapsed/refractory multiple myeloma (RRMM): update of the phase 1/2 EVOLVE study (NCT03430011).

8504 Background: Orva-cel is an investigational, BCMA-directed CAR T cell product with a fully human binder. Over 100 pts have been treated in the EVOLVE phase 1 study. Pts treated at 50 and 150 × 10 6 CAR+ T cells were previously reported (Mailankody ASH 2018 #957). We now report results of the higher dose levels (DLs) in 51 pts who received orva-cel manufactured using the process intended to support commercial use. Methods: Pts with RRMM who had ≥3 prior regimens, a proteasome inhibitor (PI), an immunomodulatory drug (IMiD), and an anti-CD38 monoclonal antibody (mAb), received orva-cel at 300, 450, and 600 × 10 6 CAR+ T cells after lymphodepletion with fludarabine/cyclophosphamide. Results: Median pt age was 61 (range, 33–77) y; median time from diagnosis was 7.0 (range, 1.7–23.6) y, with a median of 6 (range, 3–18) prior regimens. Overall, 92% of pts were penta-exposed (2 IMiDs, 2 PIs, and an mAb); 61% of pts received bridging therapy (77% were refractory to bridging therapy). Two pts had dose-limiting toxicities: grade 3 neurological event (NE) for >7 d at 300 × 10 6 CAR+ T cells and grade 4 neutropenia for >28 d at 450 × 10 6 CAR+ T cells. Key efficacy and safety outcomes are shown in the Table. Cytokine release syndrome (CRS)/NEs were managed with tocilizumab and/or steroids (78%), anakinra (14%), and/or vasopressors (6%). Grade ≥3 anemia, neutropenia, and thrombocytopenia at 29 d occurred in 21%, 55%, and 44% of pts (median time to resolution to grade ≤2 of any cytopenia, ≤2.1 mo). Grade ≥3 infections occurred in 14%. After a median follow-up (F/U) of 5.9 mo, median progression-free survival was not reached. Conclusions: Orva-cel at 300, 450, and 600 × 10 6 CAR+ T cells demonstrated manageable safety (CRS grade ≥3: 2%; NE grade ≥3: 4%) and compelling efficacy in heavily pretreated pts with RRMM, with a 91% objective response rate (ORR) and 39% complete response (CR)/stringent CR (sCR) rate. Updated results will be presented, including minimal residual disease, durability of response, and recommended phase 2 dose. Clinical trial information: NCT03430011 . [Table: see text]