ROCK2 and chronic graft versus host disease: In preclinical models, belumosudil was shown to significantly reduce lung and skin fibrosis in animal models which supported the hypothesis that ROCK2 inhibition may be an effective treatment in chronic GVHD, whose pathological hallmark is fibrosis.43 A phase II, open-label, dose finding study of belumosudil in patients with chronic GVHD who received 1-3 prior lines of systemic therapy showed promising results.44 The ORR at any time was 65%, including 60% in patients with severe chronic GVHD, and a median time-to-next-treatment of 14 months.