Posttransplant cyclophosphamide: a universal graft versus host disease prophylaxis

The purpose of this review is to outline current graft versus host disease (GvHD) prophylaxis, in the era of posttransplant cyclophosphamide (PTCY), in patients with malignant and nonmalignant hematologic disorders. The original combination of PTCY with a calcineurin inhibitor (CNI) and mycophenolate (MMF), reported from the Johns Hopkins University in Baltimore, was designed for patients receiving a graft from a donor mismatched at one haplotype, so called haploidentical donor (HAPLO). In the past decade, PTCY has been widely used in HAPLO transplants worldwide, confirming the amazing efficacy of PTCY in preventing GvHD in mismatched grafts.

More recently, PTCY is being tested also in grafts from human leukocyte antigen (HLA) identical related or unrelated donors. In the present review we will also answer several open questions, such as: PTCY and cardiac toxicity; PTCY dose; PTCY timing; PTCY and antithymocyte globulin (ATG); engraftment kinetics; infections; PTCY and leukemia relapse; PTCY and HLA identical grafts.

PTCY is currently one of the most effective measures to prevent GvHD, and can be customized in different transplant platforms, together with other immunosuppressive agents. There is place for improvement, and several possible modifications of PTCY dose and schedule can be tested in prospective trials.