Arcellx reports results from CART-ddBCMA Phase 1 expansion trial

Arcellx announced continued robust long-term responses from its CART-ddBCMA Phase 1 expansion trial in patients with relapsed or refractory multiple myeloma, dosing of first patients in its iMMagine-1 Phase 2 clinical trial with pivotal drug product, and the initiation of the Phase 1 clinical trial of ACLX-002 for the treatment of patients with relapsed or refractory acute myeloid leukemia and high-risk myelodysplastic syndromes. 38 patients were evaluable for efficacy and safety analysis as of the October 31, 2022 cutoff date, based on follow-up of at least one month, following treatment. These evaluable patients comprised the dose escalation cohorts for the first dose level and the second dose level, and a dose expansion cohort at 100. The median dose administered to patients in the first dose level and dose expansion cohorts was 115M CAR+ T cells. All patients evaluable for this analysis have poor prognostic factors with 38 of 38 patients triple-refractory, 26 of 38 penta-refractory, and 22 of 38 with at least one high-risk prognostic factor. All 38 patients had at least 3 prior lines of therapy. The interim CART-ddBCMA Phase 1 clinical results demonstrate deep and durable responses in patients with poor prognostic factors. Based on these data, the recommended Phase 2 dose was selected to be 115 (+/- 10M) CAR+T cells.