Elranatamab is a bispecific antibody that targets B-cell maturation antigen (BCMA)-expressing multiple myeloma (MM) cells and CD3-expressing T-cells. Elranatamab is currently being investigated in a phase 2 study, MagnetisMM-3, in patients with relapsed/refractory MM (RRMM). Nizar Jacques Bahlis presented results at the 2022 American Society of Hematology meeting from cohort A, which included patients with RRMM and no prior BCMA-targeted treatment.
A total of 123 patients were treated with elranatamab in cohort A. Patients received a median of 5 prior lines of therapy, 96.7% were triple-class refractory, and 42.3% were penta-drug refractory. Approximately half (51.2%) of patients were still receiving treatment at cutoff. After a median follow-up of 10.4 months, the median duration of treatment was 5.6 months, and 48% of patients had been treated for more than 6 months. The objective response rate was 61%, and benefit was seen across subgroups including patients with high-risk cytogenetics and extramedullary disease. Likewise, clinical benefit was seen in patients regardless of number of prior lines of therapy. In total, 55.3% achieved a very good partial response or better and 27.6% achieved a complete response or better. The median time to objective response was 1.2 months, and the median duration of objective response has not been reached. Minimal residual disease (MRD) negativity at 105 was evaluable in 22 patients, and 90.9% of those patients achieved MRD negativity. Median progression-free survival and overall survival have not been met.
The most common grade 3 or 4 adverse events (AEs) were hematologic: 36.6% had anemia, 48% had neutropenia, 22% had thrombocytopenia, and 24.4% had lymphopenia. Cytokine release syndrome occurred in 57.7% of patients, with all cases grade 1 or 2, and was confined to the first 3 doses. Immune effector cell–associated neurotoxicity syndrome was reported in 3.4% of patients, and all events were low grade. Other common non-hematologic AEs were diarrhea, fatigue, decreased appetite, nausea, and injection-site reaction. Infections were reported in 66.7% of patients, median time to onset was 47.5 days, and COVID-19–related deaths were seen.
These data suggest a promising benefit with elranatamab treatment in patients with RRMM with no prior history of BCMA-targeted treatment and support the continued research of elranatamab in patients with MM.
- Bahlis NJ, Tomasson MH, Mohty M, et al. Efficacy and safety of elranatamab in patients with relapsed/refractory multiple myeloma naïve to B-cell maturation antigen (BCMA)-directed therapies: results from cohort a of the MagnetisMM-3 study. Presented at: 2022 American Society of Hematology Annual Meeting; December 10-13; New Orleans, LA. Abstract 159.