Microtransplantation for Acute Myeloid Leukemia: A Systematic Review.

Importance: There has been recent interest in microtransplantation of hematopoietic cells to treat hematologic cancers, especially acute myeloid leukemia (AML) and, to a lesser extent, myelodysplastic syndrome (MDS). Most of this interest comes from data from relatively small, uncontrolled clinical trials. Objective: To determine the extent to which published data support the safety and effectiveness of microtransplantation of hematopoietic cells in persons with AML and MDS, examine what clinical data are needed to conclude that microtransplantation is safe and effective, explore microtransplantation's possible mechanisms of action, and determine whether this intervention is appropriately named. Evidence Review: PubMed was searched from 1966 to April 1, 2020, with the search terms micro-transplantation AND leukemia AND/OR myelodysplastic syndrome with boolean operators. The search identified 14 records; 11 additional records were identified by screening published reviews. A total of 15 records remained after removing duplicates and records without full text, and 14 studies were included in the qualitative synthesis. Findings: Among the 14 studies including about 600 patients, data from 5 phase 2 studies and 6 case reports of persons with AML included few heterogeneous persons and had obvious selection biases. The single randomized clinical trial also enrolled few persons. There was only 1 phase 2 study of persons with MDS. Point estimates of outcomes in both settings had wide 95% CIs. Conclusions and Relevance: This study suggests that, to date, there are no convincing data on the safety or effectiveness of microtransplantation in persons with AML or MDS. This strategy should be considered investigational and performed in the setting of controlled clinical trials.