What this Trial Is About

This is an open-label, single group, Phase 1/2, 1-arm study for treatment of children aged 1 to \<18 years with active moderate-to-severe cGVHD that is refractory to or recurred after at least 2 prior lines of systemic therapy for cGVHD. The purpose of Phase 1 is to determine the PK profiles and to establish the Recommended Pediatric Equivalent Dose (RPED) of belumosudil in participants aged 1 to \<12 years with active moderate to severe cGVHD. Upon completion and evaluation of Phase 1, Phase 2 will commence with the purpose of determining safety and efficacy (ORR by 24 weeks) of belumosudil in participants aged 1 to \<18 years. Study details include: The end of study is defined as 3 years after the last participant is recruited or all participants have discontinued treatment, or have died, whichever comes first. Minimum of 6 participants ages 1 to 6 years will be enrolled for each phase of study Individual participant duration on study will consist of: Up to 4 weeks for screening. Treatment until clinically significant progression of cGVHD, relapse/recurrence of the underlying disease, start of a new systemic treatment for cGVHD, experience of an unacceptable adverse event, request from participant or Investigator, or until the end of the study is reached, whichever comes first. 4 weeks of post treatment safety follow-up. Long-term follow-up until death or end of study, whichever occurs first.

A Study of Belumosudil in Children With Chronic Graft Versus Host Disease (schoolROCK)