Prophylactic and therapeutic treatment of graft-versus-host disease in Japan

Allogeneic hematopoietic stem cell transplantation in Japan is very different from that in Western countries in terms of the homogeneous genetic background, the preference for bone marrow to peripheral blood stem cells, use of a single unit in cord blood transplantation, and frequent use of non-myeloablative preconditioning due to a large number of elderly patients. Therefore, conclusions obtained from well-designed prospective and/or comparative studies of treatment of graft-versus-host disease (GVHD) performed in the United States or Europe may not fit Japanese transplant patients. This article reviews the studies of prophylactic and therapeutic treatment of acute and chronic GVHD that have been conducted in Japan. A randomized study demonstrated a lower incidence of acute GVHD in tacrolimus-based prophylaxis than in cyclosporine A-based prophylaxis. Retrospective and non-randomized prospective studies suggest that cyclosporine A-based and tacrolimus-based GVHD prophylaxis regimens are well researched and nearly optimized for Japanese patients, including infusion methods and target blood concentration. However, most other studies were performed in a single institute including a small number of patients, resulting in biased conclusions. There is no conclusive report on steroid-refractory acute and chronic GVHD. This review provides a baseline for starting prospective studies to create new evidence for GVHD treatment from Japan.