Novel strategies to prevent relapse after allogeneic haematopoietic stem cell transplantation for acute myeloid leukaemia and myelodysplastic syndromes

Purpose of reviewRelapse of haematological neoplasms after allogeneic haematopoietic stem cell transplantation (HSCT) remains one of the leading causes of death. Treatment of relapse post-HSCT is frequently ineffective and outcomes are poor, necessitating preventive strategies that are reviewed below.Recent findingsCurrent strategies to prevent relapse after HSCT are geared towards four general principles: improving the antitumour effects of conditioning regimens prior to HSCT, improving graft selection and engineering to augment the graft-versus-leukaemia effect, post-HSCT chemotherapeutic interventions to impair growth of residual clonal cells and post-HSCT immune-mediated interventions to enhance the graft-versus-leukaemia effect. Strategies based on cell manipulation, namely natural killer (NK) cell enrichment and adoptive T cell transfer, are emerging. Targeted therapies including vaccinations, FLT3 inhibitors, mAbs and chimeric antigen receptor T cell therapy represent a new avenue of treating acute myeloid leukaemia (AML) and myelodysplastic syndromes (MDS). Studies are underway to incorporate all of these strategies in the clinical setting to determine their impact on relapse and survival after HSCT.SummaryThe most recent evidence suggests that strategies using NK cell therapy and targeted immune therapies after HSCT may change the current landscape of HSCT for AML and MDS.