Safety and efficacy of the ROCK-2-inhibitor Belumosudil in cGvHD treatment - a retrospective, German-Swiss multicenter real-world data analysis.

Belumosudil is a first in class ROCK2-inhibitor approved by the FDA for the 3rd line treatment of chronic graft-versus-host disease (cGvHD). In this retrospective real-world analysis, we report safety and efficacy data of belumosudil treatment from 5 German/Swiss transplant centers. A total of 33 adult patients (median age 59 years) with moderate (n = 2) or severe (n = 31) cGvHD were treated on individual request due to lack of EMA approval. The patient cohort had a long history of cGvHD (median 44 months) and was heavily pretreated (median 4 prior lines). The overall response rate was 42% (95%CI, 25-60%) including organ responses in all organs except the liver (n = 2). The median time to response was 3 months (range, 1-9 months) and 8 of 14 patients (57%) had a durable response at last follow-up. One-third of patients had at least a 50% reduction in concomitant corticosteroid dosage. Median failure-free survival and median overall survival were 16.5 and 23.1 months, respectively. Adverse events ≥CTCAE grade 3 were reported in 27% of patients, with a predominance of infectious events, including one fatal course. The results are consistent with previous prospective trials including a favorable safety profile, while acknowledging the challenges of a heavily pretreated patient cohort.