Bone marrow versus peripheral blood as a graft source for haploidentical donor transplantation in adults using post-transplant cyclophosphamide—A systematic review and meta-analysis

Background Peripheral-blood (PB) and bone marrow (BM) are both widely used in hematopoietic stem cell transplantation (HSCT). However, it is unclear whether PB or BM produces a more satisfactory outcome in haploidentical HSCT, particularly for patients using post-transplant cyclophosphamide (PTCy), which is the standard therapy. However, to date, no meta-analysis focusing on this issue has been published. Methods We systematically searched PubMed, MEDLINE, Web of Science, the Cochrane Library and the ClinicalTrials.gov website for studies regarding the use of BM or PB in haploidentical HSCT for hematological malignancies in adults using PTCy. Data were analyzed using Open Meta-Analyst statistical software. Results Fourteen studies were extracted including four comparative retrospective reports and ten single-arm reports, with a total of 1759 patients received PTCy haploidentical HSCT (462 patients received PBSCT, 1297 patients received BMT). The pooled outcomes of comparative retrospective studies showed significantly higher incidence of grade III-IV acute graft-versus-host disease (GVHD) (OR = 1.741, 95%CI 1.032-2.938), incidence of grade II IV acute GVHD (OR = 1.778, 95%CI 1.314, 2.406) and engraftment rate (OR = 1.843, 95%CI 1.066-3.185) in the PB group. No significant differences were found on the incidence of relapse, 2-year overall survival (OS) and disease-free survival (DFS), acute II IV GVHD and chronic GVHD between PBSCT or BMT. Conclusion The efficacy of PB is not inferior to BM for patients undergoing PTCy haploidentical HSCT with regard to primary outcomes, including OS, DFS, NRM and relapse. However, with regards to convenience and pain relief, PB graft is suitable for haploidentical HSCT, but with a higher risk of acute GVHD.