Carfilzomib for Treatment of Refractory Chronic Graft-versus-Host Disease: A Chronic GVHD Consortium Pilot Phase II Trial

Previously reported experimental and clinical data suggest that proteasome inhibition may have immunomodulatory activity relevant to graft-versus-host disease (GVHD). To explore the safety and activity of carfilzomib in advanced chronic GVHD, we conducted a multicenter pilot phase II trial through the Chronic GVHD Consortium. Carfilzomib was administered at 20 mg/m(2) on day 1, then 36 mg/m(2) on days 8 and 15 of a 28-day treatment cycle (cycle 1), and then 36 mg/m(2) on days 1, 8, and 15 of a 28-day treatment cycle (cycles 2 to 6). The primary endpoint was 6-month treatment failure, a composite endpoint including death, relapse, and requirement for an additional line of systemic immunosuppressive therapy. A total of 20 subjects were enrolled at 4 institutions. The median time from chronic GVHD onset to enrollment was 1.5 years (interquartile range, 0.5 to 3.7 years). Chronic GVHD was National Institutes of Health category moderate (30%) or severe (70%), predominantly classic (90% versus overlap 10%), and involved multiple diverse organ sites. The number of previous lines of systemic therapy for chronic GVHD was <= 2 in 6 patients (30%) and >= 3 in the other 14 (70%). Doses were held primarily for infection (50% of total held doses); only 3 patients (15%) completed all planned doses of the 6 cycles of carfilzomib. Serious adverse effects occurred in 40% of the patients, and 7 patients died, between .3 and 9 months after the last carfilzomib dose, but no deaths were attributed to carfilzomib. The 6-month treatment failure rate was not significantly improved versus the historical benchmark rate (40% versus 44%; P=.36). Overall survival was 80% at 6 months and 65% at 12 months. Failure-free survival at 12 months was 32%. These pilot phase II data suggest that carfilzomib therapy in this advanced chronic GVHD population did not improve over the expected 6-month treatment failure rates achieved under conventional practices and is not recommended for further study for this indication. (C) 2019 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.