Efficacy and safety of the ROCK2-inhibitor belumosudil for chronic GVHD: results from a multicenter retrospective analysis of a large German-Austrian cohort of the belumosudil MAP.

Chronic graft-versus-host disease (GvHD) is a significant risk factor for late morbidity and mortality after allogeneic stem cell transplantation. In Europe, so far there were no standard treatment options available after failure of corticosteroids and ruxolitinib. The selective ROCK-2 inhibitor belumosudil, a novel FDA-, and recently EMA-approved agent, has shown efficacy in phase-2 trials and had been made available to German and Austrian patients within a managed-access program (MAP). In a retrospective multicenter study, we analyzed 144 patients with predominately severe chronic GvHD (72%) receiving belumosudil within the MAP after a median of four prior therapeutic agents. The objective response rate at one and six months was partial remission or better in 53 and 52 patients (37% and 56%). Responses were observed across all organ systems. Median time to response was 1.3 months. At six months, steroids could be discontinued in 35% and reduced in 33% of patients. Failure-free survival was 81.9% and 75.8% at six and nine months. Six months overall survival was 96.9%. Treatment-emergent adverse reactions CTCAE grade III-IV were mostly infectious complications and occurred in 28 patients (22%). This retrospective analysis of a large real-world cohort demonstrates efficacy and safety of belumosudil in refractory chronic GvHD patients.