Effects of different types of allogeneic hematopoietic stem cell transplantation donors on Philadelphia chromosome-positive acute lymphoblastic leukemia during the tyrosine kinase inhibitor era: A systematic review and meta-analysis

Background: Matched donor (MD) allogeneic hematopoietic stem cell transplantation (allo-HSCT) is currently the preferred choice of treatment for Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph^þ ALL) patients who have achieved complete remission. This systematic review and meta-analysis was conducted to investigate the effects of allo-HSCTs from different donor types for Ph^þ ALL patients who received tyrosine kinase inhibitors (TKIs). Methods: Studies in EMBASE and MEDLINE between inception and December 2020 were identified using search terms related to “Ph^þ ALL” and “HSCT.” Eligible studies were studies with Ph^þ ALL patients who received a TKI and allo-HSCT. The primary outcomes of interestdthe overall survival (OS) or relapse-free survival (RFS)dneeded to be reported. The ManteleHaenszel method was used to combine the effect estimates and associated 95% confidence intervals (CIs) of each donor type. Results: Fourteen cohort studies were identified for the meta-analysis. Haploidentical (HID)-HSCT for Ph^þ ALL patients resulted in a superior RFS to MD-HSCT, with a pooled odds ratio (OR) of 1.57 (95% CI, 1.05e2.32; I² ¼ 0%). However, HID-HSCT and MD-HSCT had comparable OS. Furthermore, HID-HSCT group had a significantly lower relapse rate than MD-HSCT group. On the other hand, the risks of graft-versus-host disease (GvHD) were higher for HID-HSCT and pooled OR of chronic GvHD rate. The OS and RFS of matched sibling-HSCT, matched unrelated-HSCT, and cord blood-HSCT were comparable with those of HID-HSCT. Conclusion: This systematic review and meta-analysis showed that HID-HSCT is as effective as MD-HSCT in Ph^þ ALL patients.