Abstract
Second-line therapy for corticosteroid-refractory or -dependent acute graft-versus-host disease remains ill-defined, due to limited efficacy of drugs and evolving clinical trial endpoints. Six-month freedom from treatment failure has been proposed as a novel clinical trial endpoint and is defined by the absence of death, malignancy relapse/progression, or addition of a next line of systemic immunosuppressive therapy within 6 months of intervention and prior to diagnosis of chronic graft-versus-host disease. We analyzed the 6-month freedom from treatment failure endpoint in 128 patients enrolled from three centers who were treated with extracorporeal photopheresis as second-line therapy for acute graft-versus-host disease. The incidence of 6-month freedom from treatment failure was 77.3% with a 2-year survival rate of 56%. Corticosteroid dose or response status at onset of second-line therapy did not influence outcome. Higher grade of acute graft-versus-host disease (grade 2 versus grades 3-4) at onset of photopheresis predicted for poor outcome as measured by survival (hazard ratio 2.78, P<0.001), non-relapse mortality (hazard ratio 2.78, P=0.001) and 6-month freedom from treatment failure (hazard ratio 3.05, P<0.001). For the 91 patients who achieved 6-month freedom from treatment failure, 1-year, 2-year and 3-year survival rates were 78.9%, 70.8% and 69.5%, respectively. Six-month freedom from treatment failure is a reasonable early surrogate for outcome and should be considered as a clinical trial endpoint. This study demonstrates the durable effect of photopheresis as second-line therapy for corticosteroid-refractory or -dependent acute graft-versus-host disease using 6-month freedom from treatment failure as the primary endpoint.