On July 17, 2021, Kadmon Holdings announced that the U.S. Food and Drug Administration (FDA) has approved Rezurock (belumosudil) 200 mg once daily (QD) for the treatment of pediatric patients (≥12 years of age) and adult patients with chronic graft-versus-host disease (cGVHD) who have failed at least two prior systemic therapies. cGVHD is a common and fatal complication following hematopoietic stem cell transplantation. In cGVHD, transplanted immune cells (grafts) attack the patient's cells (host), leading to inflammation and fibrosis in multiple tissues, including the skin, mouth, eyes, joints, liver, lungs, esophagus, and gastrointestinal tract.
Notably, Rezurock is the first and only ROCK2 small molecule inhibitor approved by the FDA. The ROCK2-mediated signaling pathway plays a crucial role in regulating inflammatory and fibrotic responses. The FDA previously granted belumosudil Breakthrough Therapy Designation and Orphan Drug Designation for the treatment of cGVHD patients. Its new drug application also received priority review designation and was reviewed under the FDA's Real-Time Oncology Review (RTOR) and Orbis pilot program.
FDA approval was based on the results of the ROCKstar randomized, open-label, multicenter pivotal clinical trial. A total of 65 patients received Rezurock, and the trial results showed that Rezurock achieved an overall response rate (ORR) of 75% and a complete response rate of 6%. The median time to first response was 1.8 months. 62% of patients who achieved a response did not require new systemic therapy for at least 12 months after the response. The median duration of response (defined as the time from first response to disease progression, death, or need for new systemic therapy) was 1.9 months.
