Predictors and outcomes of flares in chronic graft-versus-host disease.

Chronic graft-versus-host disease (cGVHD) after allogeneic hematopoietic cell transplantation (HCT) requires prolonged immunosuppressive therapy (IST), often requiring slow tapering with patients experiencing cGVHD flares and treatment failure. In 145 adult recipients developing cGVHD after matched sibling or umbilical cord blood donor HCT from 2010 to 2018, 2-year cumulative incidence of flares after cGVHD diagnosis was estimated at 60% (95% CI, 51-70%), with median time-to-first flare of 188 days (range, 16-751). Of 88 patients experiencing a flare, 32 (36%) had multiple flares (range, 2-4). First flare treatment consisted of an increase in prednisone dose in 77 patients (88%), plus topical therapy in 8 (9%) or another systemic IST in 43 patients (49%). Higher flare risk was associated with quiescent type of cGVHD at onset (HR 1.8; 95% CI: 1.1-2.7; p = 0.04). Patients without a flare required a shorter duration of IST and were more likely to achieve a durable discontinuation of systemic IST (86% vs. 31% for ≥6 consecutive months). Flares were associated with protective effect on relapse (HR 0.2, 95% CI: 0.1-0.3), however not with worsened 2-year NRM or OS. Flares of cGVHD identify a group needing better approaches to limit the duration of IST and thus the morbidity of cGVHD.