ROCKstar: Response dynamics to belumosudil in cGvHD

During the 67th American Society of Hematology (ASH) Annual Meeting and Exposition, December 6–9, 2025, Orlando, US, Zachariah DeFilipp presented an ad hoc analysis of the phase II ROCKstar trial (NCT03640481) dataset evaluating time to response (TTR) and patterns of organ-specific improvement over the first year of belumosudil therapy in patients with chronic graft-versus-host disease (cGvHD) and long-term follow-up (N = 114). 

Key data: After median follow-up of 30.4 months, median overall TTR was 4.4 weeks, where 5.3% of all responses occurred after 24 weeks of belumosudil treatment. The shortest median TTR was observed for lower gastrointestinal tract involvement (4.1 weeks), whereas the longest median TTRs were observed for lungs (16.1 weeks), mouth (11.9 weeks), and skin (9.6 weeks). The highest proportion of late responses (after 12 weeks) were lungs (46.7%) and eyes (29.8%). 

Key learning: Belumosudil achieved clinical responses across all involved organs in cGvHD, with varying response kinetics by organ. The findings underscore the importance of managing clinical expectations and tailored treatment duration based on organ-specific response dynamics.