Belumosudil Demonstrates Steroid-Sparing, Safety, and Efficacy in Pediatric Chronic Graft-Versus-Host Disease

Chronic graft-versus-host disease (cGVHD) causes morbidity and mortality in pediatric patients following allogenic hematopoietic stem cell transplantation. Standard first-line therapy with corticosteroids is often insufficient, causes significant side effects, and many children require multiple other lines of systemic therapy. Belumosudil, an oral ROCK2 inhibitor, has demonstrated immunomodulatory and antifibrotic effects and is FDA-approved for cGVHD if ≥12 yr after failure of at least two prior systemic therapies. Data in pediatrics remains limited. We conducted a single-institution retrospective analysis of pediatric patients with steroid resistant/progressive cGVHD at Rady Children's Hospital of Orange County treated with belumosudil between September 2021 and July 2025. Eleven patients were identified. Longitudinal responses across organ systems, with National Institutes of Health consensus scoring, steroid dose reductions, pulmonary function testing (PFT), laboratory parameters, lung scans, and qualitative symptom assessments, were collected. Of 11 patients treated with belumosudil, 10 demonstrated partial response and one a complete response. Corticosteroid and other immunosuppressant use decreased in 9 patients. PFTs were stable, with improved clinical pulmonary symptoms. Qualitative improvements were decreases in rash, gastrointestinal upset, and dry eyes. Safety was acceptable, with no peripheral blood count suppression or serious infections. Good compliance was observed, with no discontinuation due to side effects. Belumosudil demonstrates promising efficacy in treating pediatric cGVHD by offering clinically meaningful responses with an acceptable safety profile. Its corticosteroid-sparing potential and impact on quality of life further support its role in the management of cGVHD. Continued investigation in younger children and in earlier lines of therapy is warranted to optimize outcomes in this vulnerable population.