In total, 146 patients (71 patients in the 120 mg cohort and 75 in the 240 mg cohort) were accrued over 57 global sites and started treatment between Jun 2022 and Sep 2023. The data cutoff date for this final analysis was Feb 9, 2024. The median number of prior lines of therapy received was 6 (range, 3–17) in the 120 mg cohort and 6 (range, 3–15) in the 240 mg cohort. Rates of exposure to prior anti-B cell maturation antigen therapy were 48% and 43%, respectively. At a median follow-up of 7.3 months, the ORR was 32% (95% confidence interval [CI], 22–45%) in the 120 mg cohort and 41% (95% CI, 29–52%) in the 240 mg cohort, with median progression-free survival of 4.1 and 5.3 months, and median duration of response of not estimable and 9.2 months, respectively. In the combined cohort of 146 patients, ORR was 29% in patients exposed to an anti-B-cell maturation agent (BCMA), and 44% in non-anti-BCMA-exposed patients. Rates of grade 3 or higher adverse events (AEs) were 90% in the 120 mg cohort and 96% in the 240 mg cohort, with the majority of AEs being hematologic (grade 3–4 hematologic AE rates: 86% and 92%, respectively). Grade 3 and 4 thrombocytopenia were observed in 28% and 27% of patients in the 120 mg cohort, and 32% and 29% of patients in the 240 mg cohort, respectively. Grade 3 and 4 neutropenia were observed in 35% and 21% of patients in the 120 mg cohort, and 45% and 23% of patients in the 240 mg cohort, respectively. Rates of serious AEs were 39% in the 120 mg cohort and 44% in the 240 mg cohort. Rates of grade 3–4 infections were 21% and 15%, respectively. Infusion-related reactions (IRRs) were observed in 25% of patients in the 120 mg cohort, and 16% of patients in the 240 mg cohort, with rates of grade 3 IRRs of 3% in each cohort. Three patients (4%) died on study in the 120 mg cohort, and 5 patients (7%) died on study in the 240 mg cohort.