Belumosudil for Chronic Graft-Versus-Host Disease (cGVHD) after 2 or More Prior Lines of Therapy: The Rockstar Study (KD025-213)

Belumosudil, an investigational oral selective inhibitor of rho-associated coiled-coil-containing protein kinase-2 (ROCK2), reduces type 17 and follicular helper T cells via downregulation of signal transducer and activator of transcription 3 (STAT3) and enhances regulatory T cells via upregulation of signal transducer and activator of transcription 5 (STAT5). Belumosudil may effectively treat patients with cGVHD, a major cause of morbidity and late nonrelapse mortality after an allogeneic hematopoietic cell transplant. This phase 2, randomized, multicenter registration study evaluated belumosudil 200 mg QD (n=66) and 200 mg BID (n=66) in subjects with cGVHD who had received 2 to 5 prior lines of therapy. The primary end point was best overall response rate (ORR). Duration of response (DOR), changes in Lee Symptom Scale score, failure-free survival, corticosteroid dose reductions and overall survival were also evaluated. Overall median follow-up was 14 months. The best ORR (95% CI) of belumosudil 200 mg QD and 200 mg BID was 74% (62%-84%) and 77% (65%-87%), respectively, with high response rates observed in all subgroups. All affected organs demonstrated complete responses. The median DOR was 54 weeks; 44% of subjects have remained on therapy for ≥1 year. Symptom reduction with belumosudil 200 mg QD and 200 mg BID was reported in 59% and 62% of subjects, respectively. Adverse events (AEs) were consistent with those expected in patients with cGVHD receiving corticosteroids and other immunosuppressants. Sixteen subjects (12%) discontinued belumosudil due to possible drug-related AEs. Belumosudil, a promising therapy for cGVHD, was well tolerated with clinically meaningful responses. (Funded by Kadmon Corporation, LLC; ClinicalTrials.gov number, NCT03640481.).