Extracorporeal Photopheresis as Graft-versus-Host Disease Prophylaxis: A Randomized Controlled Trial

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the sole curative option for many patients diagnosed with hematologic malignancies. A major obstacle is graft-versus-host disease (GVHD), causing significant morbidity and mortality. Extracorporeal photopheresis (ECP) is an increasingly applied treatment for GVHD, owing in part to its favorable safety profile. In contrast, reports on the use of ECP to prevent GVHD are rare, and randomized controlled trials (RCTs) are lacking. We conducted an RCT to assess whether ECP applied post-transplantation could prevent the development of GVHD within the first year of transplantation. We enrolled 157 patients (age 18 to 74 years) with a hematologic malignancy undergoing their first allo-HSCT, randomized as 76 to the intervention group and 81 to the control group. ECP was initiated directly on engraftment and was planned twice weekly for 2 weeks, then once weekly for 4 weeks. GVHD, relapse, and death were analyzed by Cox regression analysis. During the first year, 45 patients in the intervention group and 52 control patients developed GVHD (hazard ratio [HR], .82; 95% confidence interval [CI], .55 to 1.22; P = .32). There were no differences in acute or chronic GVHD or its organ distribution in this intention-to-treat RCT. A per-protocol analysis revealed a significant difference in GVHD between the intervention group (per-protocol; n = 39 of 76) and the control group (n = 77), 46% versus 68%, respectively (HR, .47; 95% CI, .27 to .80; P = .006). Relapse occurred in 15 patients in the intervention group and in 11 control patients (HR, 1.38; 95% CI, .64 to 3.01; P = .42). GVHD-free relapse-free survival, event-free survival, overall survival, and nonrelapse mortality did not differ significantly between the 2 study groups. There also was no significant difference in immune reconstitution between the 2 groups. This first intention-to-treat RCT investigating ECP as GVHD prophylaxis in allo-HSCT for hematologic malignancy does not support the use of ECP as an adjunct to standard drug-based GVHD prophylaxis.