Efficacy of belumosudil vs BAT in European patients with cGvHD: ROCKreal transportability analysis

Results from a ROCKreal transportability analysis, evaluating belumosudil vs physician’s choice of best available therapy (BAT) for the treatment of relapsed/refractory chronic graft-versus-host disease (cGvHD) in European patients, were recently published in Transplantation and Cellular Therapy by Wolffet al. This analysis generalized US ROCKreal study findings to European patients. Data were collected from 196 US and 222 European patients aged ≥12 years with cGvHD treated with 2–5 prior lines of therapy (LoT), with visits between March 2015 and 2024 from 8 US and 32 European sites.

Key data: Using targeted maximum likelihood estimation (TMLE), the estimated 6-month overall response rate (ORR) was 37.6% with belumosudil vs 26.3% with BAT (ORR ratio, 1.427; 95% confidence interval [CI], 1.05 to ∞; p = 0.03). The ORR difference between belumosudil and BAT in the European population was 0.113 (95% CI, 0.08–1; p = 0.04). A sensitivity analysis further suggested benefit (ORR, 40.2% vs 27.0%), though this did not reach statistical significance. Notably, European outcome data were not directly observed; all efficacy estimates were modeled from US data.

Key learning: This transportability analysis indicates that belumosudil would provide clinically meaningful benefits over BAT in European patients with cGvHD after failure of 2–5 prior LoT, with comparable treatment-response patterns observed between US and European populations.