Prophylactic treatment of postallograft relapse in acute myeloid leukaemia

Haematopoietic stem cell allograft transplantation (HSCT) is a curative procedure for patients with high-risk acute myeloid leukaemia (AML) in initial remission. However, disease relapse remains the main cause of allograft failure, occurring in around 35-45% of patients. Survival of patients who relapse after allo-HSCT is generally short, hence the need for early prophylactic intervention to reduce the risk or perhaps delay relapse. Myeloablative conditioning regimens, monitoring of measurable residual disease (MRD) and donor chimerism, rapid reduction of immunosuppression and donor lymphocyte infusion (DLI) are well known strategies in practice. However, other preventive pharmacological interventions after allograft can control leukaemia through two parallel mechanisms : direct cytotoxic anti-leukaemic activity and graft immunological activity against leukaemia. This review will discuss the use of preventive drugs after allograft transplantation, including hypomethylating agents such as azacitidine, and inhibitors of FLT3 and IDH1/2.