A Clinical Study to Evaluate the Pharmacokinetics, Efficacy, and Safety of Belumosudil in Chinese Adolescents With cGVHD Who Have Had an Inadequate Response to Glucocorticoids or Other Systemic Therapies

This is a single group, Phase 4, single-arm post-marketing study for treatment. The purpose of this study is to verify the pharmacokinetics, efficacy, and safety of belumosudil mesylate tablets in Chinese adolescent participants (aged from 12 to less than 18) with cGVHD who have had an inadequate response to glucocorticoids or other systemic therapies. Participants will receive treatment with belumosudil tablets 200 mg once daily in 28-day cycles during the study.