Janssen Pharmaceutical Companies of Johnson & Johnson announced initial results from the Phase 1b/2 Cartitude-1 study evaluating the efficacy and safety of JNJ-68284528, an investigational B cell maturation antigen-directed chimeric antigen receptor T cell therapy being evaluated in the treatment of patients with relapsed or refractory multiple myeloma. The study enrolled patients who have received at least three prior lines of therapy or are double refractory to a proteasome inhibitor and an immunomodulatory drug; have received a PI, IMiD and an anti-CD38 antibody; and who progressed on or within 12 months of their last line of therapy. Results from the Phase 1b portion of the study showed "early and deep responses" among 29 patients with a median of five prior multiple myeloma treatment regimens treated with JNJ-4528, with 100% of patients achieving a response at a median six-month follow-up, Janssen said. The overall response rate included 69% of patients achieving a complete response or better; 86% of patients achieving a very good partial response or better; and 14% of patients achieving a partial response. In addition, 100% of evaluable patients achieved early minimal residual disease-negative disease status at day 28 post-infusion. At the six-month follow-up, 27 of 29 patients were progression-free. Based on the Phase 1b results, a recommended Phase 2 dose of 0.75x106 CAR+ viable T cells/kg was confirmed, the company added. The most common adverse events observed in the study were cytokine release syndrome, neutropenia, anemia and thrombocytopenia.