Belumosudil for chronic graft-versus-host disease after 2 or more prior lines of therapy: the ROCKstar Study

Phase 2 randomised multicentre registration study of belumosudil, an oral selective ROCK2 inhibitor that reduces type 17 and follicular T helper cells and enhances regulatory T cells, at 200 mg daily (66 patients) and 200 mg twice daily (66) in chronic graft-versus-host disease after 2 to 5 prior lines of therapy. The primary endpoint was best overall response rate; duration of response, Lee Symptom Scale change, failure-free survival, corticosteroid dose reduction and overall survival were also evaluated.

At a median follow-up of 14 months the best overall response rate was 74 percent (95% CI 62 to 84) with 200 mg daily and 77 percent (95% CI 65 to 87) with 200 mg twice daily, with high response rates in all subgroups and complete responses in all affected organs. Median duration of response was 54 weeks and 44 percent of patients remained on therapy for at least a year. Symptom reduction was reported in 59 and 62 percent. Sixteen patients (12 percent) discontinued because of possible drug-related adverse events.