Matching-Adjusted Indirect Comparison of Elranatamab versus Teclistamab in Patients with Triple-Class Exposed/Refractory Multiple Myeloma: Updated Results.

Due to the absence of a head-to-head trial directly comparing elranatamab and teclistamab in triple-class exposed/refractory multiple myeloma (TCE/R MM), a matching-adjusted indirect treatment comparison (MAIC) was previously conducted. The aim of the current study was to update this prior MAIC with more mature clinical data from both trials. The approach of the MAIC remained consistent with the previous study, with the exception of more mature data (28.4 months and 30.4 months of follow-up for elranatamab from MagnetisMM-3 (NCT04649359) and teclistamab from MajesTEC-1 (NCT03145181, NCT04557098), respectively). Individual patient-level data from MagnetisMM-3 (N = 116) were reweighted to match published aggregated data from MajesTEC-1. Variables included for adjustment were age (≥75 years), sex (for OS only), median time since diagnosis, International Staging System disease stage, high-risk cytogenetics, extramedullary disease, number of prior lines of therapy, Eastern Cooperative Oncology Group performance status, and penta-exposed/refractory status. An unanchored MAIC was conducted based on the National Institute for Health and Care Excellence Decision Support Unit 18 example code. A sensitivity analysis was conducted in which missing baseline characteristics data were imputed for elranatamab. In the base-case analysis, elranatamab was associated with significantly longer PFS (hazard ratio [HR] 0.55 [95% confidence intervals (CI): 0.37, 0.81], p < 0.05), OS (HR [95% CI]: 0.60 [0.40, 0.91], p < 0.05, and DoR 0.56 [0.31, 0.99] p < 0.05) compared with teclistamab. Results were largely consistent in the sensitivity analysis, except that the differences in OS were non-significant. A subgroup analysis of patients with a complete response or better was consistent with the base case. The results of this updated MAIC of elranatamab and teclistamab in TCE/R MM support the findings of the previous MAIC over a longer-term follow-up, now indicating significantly improved PFS, OS, and DoR with elranatamab versus teclistamab.