Recombinant Human Thrombopoietin Promotes Platelet Engraftment in Severe Aplastic Anemia Patients following Treatment with Haploid Hematopoietic Stem Cell Transplantation using Modified Post-transplantation Cyclophosphamide.

BACKGROUND: Recombinant human TPO (rhTPO) promotes platelet engraftment in patients after allogeneic HSCT (allo-HSCT). However, the effects of rhTPO on platelet recovery after Haplo-HSCT in patients with severe aplastic anemia (SAA) have not been intensively studied.

OBJECTIVE: We aimed to evaluate the efficacy of rhTPO on platelet engraftment in patients with SAA who were treated with Haplo-HSCT using post-transplantation cyclophosphamide (PTCy).

STUDY DESIGN: SAA patients who received Haplo-HSCT plus PTCy regimen were divided into the rhTPO group (with subcutaneous injection of rhTPO, n=28) and Control group (no rhTPO administration, n=27). The engraftment of platelet/neutrophil, platelet infusion amount, and transplant-related complications between the two groups were compared.

RESULTS: All 55 patients showed successful hematopoietic reconstitution. The median time of platelet engraftment was 11 (9-29) days in the rhTPO group and 14 (9-28) days in the Control group (P=0.003). The rhTPO group had a significantly reduced amount of infused platelets compared to the Control group (2 (1-11.5) vs 3 (1-14) therapeutic doses; P=0.004). There was no significant difference between the two groups regarding median time of neutrophil engraftment, incidence of acute graft-versus-host disease (aGVHD) and chronic GVHD (cGVHD), incidence of cytomegalovirus or Epstein-Barr virus reactivation, 3-year overall survival rate, and failure-free-survival rate. No obvious adverse reactions were observed in the rhTPO group.

CONCLUSION: rhTPO promoted platelet engraftment, reduced the amount of transfused platelets, and demonstrated good safety profiles without evidence of adverse reactions in patients with SAA who received Haplo-HSCT using PTCy regimen.