Ruxolitinib as second-line therapy for bronchiolitis obliterans syndrome after hematopoietic cell transplantation: a retrospective multicenter study.

Chronic graft-versus-host disease (cGVHD) is a major complication for long-term survivors after hematopoietic cell transplantation (HCT). Bronchiolitis obliterans syndrome (BOS) is the crucial manifestation of lung cGVHD. Ruxolitinib has been approved by the Food and Drug Administration (FDA) for cGVHD treatment, but the response for BOS has not been sufficiently evaluated. We conducted a multicenter study involving 125 patients diagnosed with BOS post-HCT who received second-line therapies, including 77 patients treated with ruxolitinib (ruxolitinib group) and 48 patients with non-ruxolitinib therapies (control group). The primary endpoint was progression of BOS. By the third month, 18.2% of patients in the ruxolitinib group progressed, versus 43.8% in the control group (p = 0.001). The 2-year overall survival (OS) was 73.2% (95%CI 63.5%-84.5%) for the ruxolitinib group versus 60.2% (95%CI 47.4%-76.6%) for the control group (p = 0.012). The BOS-progression-free survival (BOS-PFS) was 69.0% (95%CI 59.1%-80.5%) versus 51.2% (95%CI 38.7%-67.7%, p = 0.011). Early switch to second-line therapy for BOS independently favored lower progression incidence (OR = 0.203, [95%CI 0.070-0.585], p = 0.003). Additionally, we observed that ruxolitinib was well-tolerated during the treatment of BOS. In conclusion, our findings indicated that ruxolitinib is an effective and safe second-line option for BOS.