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/m2 on day 1, then 36 mg/m2 on days 8 and 15 of a 28-day treatment cycle (cycle 1), and then 36 mg/m2 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.