Impact of pretransplant anti-CCR4 antibody administration on clinical outcomes in allogeneic hematopoietic stem cell transplantation

Adult T-cell leukemia-lymphoma (ATL) is a peripheral T-cell lymphoma caused by human T-cell lymphotropic virus type I. Patients with aggressive ATL exhibit poor outcomes, even with dose-dense intensive chemotherapy. Thus, allogeneic hematopoietic stem cell transplantation (allo-HSCT) is considered in all patients eligible for transplant. However, patients with aggressive ATL often have chemo-refractoriness or experience early relapse during chemotherapy. Allo-HSCT is often ineffective in patients with active disease status. Mogamulizumab (Moga) was approved in 2012 in Japan as a potent treatment option for patients with relapsed or refractory ATL. However, there is a major concern that the use of Moga before allo-HSCT could increase the risk of post-transplant complications, such as graft-versus-host disease (GVHD), because Moga depletes regulatory T cells. Here, we would like to describe the possible effects of pre-transplant Moga on post-transplant complications, such as acute GVHD, and to discuss how Moga could be efficiently incorporated in the treatment regimen of patients with aggressive ATL to maximize the expected clinical benefit.