A matching-adjusted indirect treatment comparison of elranatamab in patients with triple-class exposed relapsed/refractory multiple myeloma: Comparisons with belantamab mafodotin, selinexor plus dexamethasone, and real-world physician’s choice of treatment.

Abstract

e20038 Background: Elranatamab, a bispecific antibody targeting B-cell maturation antigen on multiple myeloma (MM) cells and CD3 on T cells, is being evaluated as a monotherapy in the MagnetisMM-3 trial (MM3; NCT04649359) in patients with triple-class exposed (TCE) relapsed/refractory MM. While there is no standard of care for TCE MM, belantamab mafodotin (belamaf) and selinexor plus dexamethasone (sel-dex) are treatment options. LocoMMotion is a prospective, non-interventional study investigating real-world physician’s choice of treatment (PCT) in patients with TCE MM. In the absence of head-to-head trials, unanchored matching-adjusted indirect comparisons (MAIC) were conducted to compare the relative efficacy across comparators. Methods: Individual patient-level data were obtained for elranatamab from MM-3 (data cut Oct 2022). Aggregated data for belamaf, sel-dex, and PCT were obtained from DREAMM-2 (NCT03525678), STORM (NCT02336815), and LocoMMotion (NCT04035226). Unanchored MAICs were conducted to compare the relative treatment effect on objective response rate (ORR) accounting for potential different distributions of prognostic variables (PVs) and effect modifiers (EMs). In the base case, PVs identified via logistic regressions based on MM-3 data were adjusted. In sensitivity analyses, PVs/EMs identified from the literature were added. Relative treatment effects were measured by rate differences and odds ratios. Results: After MAIC adjustments, the selected PVs/EMs were balanced in each comparison. The table presents the results from the naïve comparison with no MAIC adjustment plus the MAIC base case. The ORR of elranatamab was statistically higher than belamaf, sel-dex, and PCT in LocoMMotion. Results were consistent across all sensitivity analyses. Conclusions: Elranatamab had a significantly higher ORR than belamaf, sel-dex, and real-world PCT in LocoMMotion for patients with TCE MM, demonstrating its clear clinical benefit for this population. [Table: see text]