A New Standard in Graft-versus-Host Disease Prophylaxis? An Introduction to Blood and Marrow Transplant Clinical Trials Network 1703

Effective immunosuppressive regimens to prevent the development of graft-versus-host disease (GVHD) are essential to the success of allogeneic hematopoietic cell transplantation (HCT). After revolutionizing haploidentical transplantation, post-transplantation cyclophosphamide (PTCy) is now being evaluated for HCT performed from related and unrelated donors. In this setting, two recent randomized studies have demonstrated lower rates of GVHD and superior GVHD-free, relapse-free survival with PTCy as compared to conventional GVHD prophylaxis. The Blood and Marrow Transplant Clinical Trials Network (BMT CTN) is currently conducting a large, randomized phase III, multicenter trial (BMT CTN 1703) comparing PTCy/tacrolimus/mycophenolate mofetil to tacrolimus/methotrexate as GVHD prophylaxis regimens in reduced-intensity allogeneic HCT. In this introductory manuscript, we review the ongoing study, highlight its importance to field, and explore the possible implications of results on clinical practice.