Adjusted Indirect Treatment Comparison of Progression-Free Survival with D-Rd and VRd Based on MAIA and SWOG S0777 Individual Patient-Level Data.

INTRODUCTION: Daratumumab plus lenalidomide and dexamethasone (D-Rd) and bortezomib plus lenalidomide and dexamethasone (VRd) are commonly used treatment combinations for transplant-ineligible (TIE) patients with newly diagnosed multiple myeloma (NDMM). D-Rd and VRd demonstrated superior efficacy relative to lenalidomide and dexamethasone (Rd) in the MAIA and SWOG S0777 trials, respectively, but have not been compared directly in a head-to-head trial. Naïve comparisons of efficacy across the two trials may be biased because MAIA enrolled only TIE patients (median age 73 years), whereas SWOG S0777 enrolled both TIE patients and transplant-eligible patients who chose to defer/refuse frontline stem cell transplantation (median age 63 years). The present study compared progression-free survival (PFS) in TIE patients with NDMM treated with D-Rd versus VRd based on an adjusted indirect treatment comparison (ITC) that leveraged individual patient-level data from MAIA and SWOG S0777.

METHODS: Harmonized inclusion/exclusion criteria (including age ≥ 65 years as a proxy for transplant ineligibility) and propensity-score weighting were used to balance the trial populations on measured baseline characteristics. After differences in trial populations were adjusted for, an anchored ITC was performed wherein within-trial PFS hazard ratios (HRs) for D-Rd versus Rd and VRd versus Rd were estimated and used to make indirect inference about PFS for D-Rd versus VRd.

RESULTS: PFS HRs were 0.52 (95% confidence interval [CI] 0.41-0.67) for D-Rd versus Rd based on MAIA data, 0.88 (95% CI 0.63-1.23) for VRd versus Rd based on SWOG S0777 data, and 0.59 (95% CI 0.39-0.90) for the Rd-anchored ITC of D-Rd versus VRd. Sensitivity and subgroup analyses produced results consistent with the primary results.

CONCLUSION: This anchored ITC demonstrated a greater PFS benefit for D-Rd versus VRd in TIE patients with NDMM. In the absence of head-to-head trials comparing D-Rd and VRd, the present trial may help inform treatment selection in this patient population.