Efficacy of Belumosudil in Bronchiolitis Obliterans Syndrome Treatment

By Patrick Daly - Last Updated: September 15, 2022

Chronic graft-versus-host disease (cGVHD) of the lung, also known as bronchiolitis obliterans syndrome (BOS), is a highly fatal complication with limited available treatment options. Researchers, led by Zachariah DeFilipp, analyzed 2 prospective trials and concluded that belumosudil treatment was associated with lung-specific clinical responses in patients with BOS, especially in less-advanced disease. Their findings were published in Blood Advances.

The analysis included 59 patients with BOS who participants in 2 prospective trials on belumosudil. At enrollment, patients had a predicted forced expiratory volume in 1 second (FEV1) of 79% and lung disease attributed to cGVHD by a clinician. A total of 30 (59%) patients had a National Institutes of Health (NIH) cGVHD lung score of 1, 23 (39%) had a score of 2, and 6 (10%) had a score of 3.

According to the authors, the best overall response rate (ORR) per NIH criteria was 32%, with 17% partial responses and 15% complete responses. Notably, the authors found response rates were inversely proportional to the baseline NIH GVHD lung score at enrollment with ORRs of 50%, 17%, and 0% for lung scores 1, 2, and 3, respectively (P=.006).

Further analyses revealed that male sex, lower NIH cGVHD score at baseline, and partial response to prior cGVHD treatment were factors associated with greater rates of lung-specific responses. Lastly, no significant associations were observed between pulmonary function assessment tool used (NIH symptom-based lung score or Lee Symptom Scale score) and BOS symptom burden measures.

The authors concluded that belumosudil was associated with clinical responses in patients with BOS, potentially representing a valuable option for this high-risk population with limited effective treatments available. However, they noted that the optimal evaluation of treatment response in patients with BOS is still unclear.

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