Key Points
Belumosudil increased 6-month overall response rate compared to best available therapy in cGVHD patients with 2-5 prior lines of therapy.
Findings from this real-world study of efficacy and safety of belumosudil are consistent with earlier clinical studies.
Belumosudil was FDA-approved in the United States (US) for the treatment of relapsed/refractory chronic graft-versus-host disease (cGVHD) based on a randomized phase II trial comparing two belumosudil doses. The efficacy and safety of belumosudil versus the best available therapy (BAT) have not been studied. Applying rigorous statistical methodology to real-world data, this study estimated the efficacy of belumosudil versus BAT in cGVHD patients whose disease failed to respond to 2-5 prior lines of therapy (LOTs). Retrospective data between March 2015 and 2024 was collected across 8 US sites on 196 patients contributing 113 belumosudil and 245 BAT LOTs. The primary outcome was 6-month overall response rate (ORR), defined as the proportion of complete or partial responses based on 2014 NIH consensus criteria, physician assessment, or corticosteroid dose taper of ≥ 50% without cGVHD progression. Death, relapse, and beginning a new LOT were considered a lack of response. Targeted maximum likelihood estimation (TMLE) was used to estimate the 6-month ORR following belumosudil versus BAT (38.7% versus 26.8%, respectively, or 44.2% improvement with belumosudil (one-sided 95% confidence interval (CI): [4.4%, ∞); p: 0.031)). TMLE was also used to estimate 1-year failure-free survival (FFS) when treated with belumosudil (61.2%) or BAT (47.8%), a 13.5% difference (95% CI: [1.5%, 100.0%), p: 0.032). Descriptive assessment of safety showed adverse events recorded in 27% of belumosudil and 36% of BAT LOTs. Findings demonstrated that belumosudil improved clinical outcomes versus BAT in cGVHD patients with 2-5 prior LOTs, and safety was consistent with belumosudil's established profile.