Extracorporeal photopheresis (ECP) is used to treat chronic graft-versus-host disease (cGVHD)—a complication of bone marrow or stem cell transplant that occurs when donor cells attack the recipient. How ECP works is unclear, and standardized treatment guidelines have not been established.

Vanderbilt medical student Jocelyn Gandelman, Madan Jagasia, MBBS, and colleagues conducted a prospective, multicenter clinical trial of ECP for cGVHD. They found that in a highly pretreated group of patients, 62.3% had a provider-assessed response to ECP and 43.5% had a response according to National Institutes of Health consensus criteria.

The researchers found no difference in peripheral blood T regulatory cells (Tregs), immune cells that may play a role in suppressing GVHD, in ECP responders vs non-responders. ECP was associated with a meaningful decrease in steroid dose, and overall severity and body surface area redness decreased with treatment.

The findings, reported in the journal Biology of Blood and Marrow Transplantation, support further study of ECP therapy.

This investigator-initiated research was funded by Therakos, Inc, a Mallinckrodt Pharmaceuticals Company.