Extracorporal Photopheresis With UVADEX Plus Standard Steroid Treatment for High Risk Acute Graft-versus-host Disease

This is a single arm phase 2 trial which includes patients with high risk acute GVHD defined as Ann Arbor score 2 or 3. The purpose of the study is to improve the outcome of these patients in terms of response to treatment and treatment related mortality. All patients will receive the study intervention (ECP with Uvadex). The study hypothesis is that the treatment plan will produce a day 28 complete response rate higher than or equal to 52%, which will represent an improvement of 15% compared with the standard of care (37%). The rate of complete response to standard of care treatment is based on observed data in similar patients treated within the Mount Sanai Acute GVHD International Consorium (MAGIC). Patients will be treated for 56 days and followed for one year to also enable evaluation of long term outcome.