Elranatamab Exposure–Safety Analysis in Relapsed or Refractory Multiple Myeloma

Elranatamab, a bispecific antibody targeting B-cell maturation antigen, is approved for the treatment of relapsed or refractory multiple myeloma (RRMM). An exposure-safety analysis was conducted using the data from patients with RRMM across four clinical studies, MagnetisMM-1, 2, 3, and 9 (NCT03269136, NCT04798586, NCT04649359, and NCT05014412). The selected safety endpoints included grade ≥3 infections, neutropenia, anemia, and thrombocytopenia. Additionally, the relationship between the elranatamab exposure and dose interruptions and discontinuation events was explored. The results showed no statistically significant relationship between elranatamab exposure and the incidence of these safety events. The flat exposure-safety relationship with the evaluated safety endpoints suggested a similar probability of experiencing these events with the 76-mg once-weekly (QW) regimen compared with lower doses within the efficacious dose range (215-1000 µg/kg, equivalent to 16-76 mg). These data support the use of a full dose of 76 mg QW and do not indicate that selecting a lower dose would significantly mitigate the risk for adverse events. Additionally, these findings support managing elranatamab adverse drug reactions through temporary dose interruption rather than dose reduction.