Recombinant Human Thrombopoietin Promotes Platelet Engraftment After Haploidentical Hematopoietic Stem Cell Transplantation: a Prospective Randomized Controlled Trial

Delayed platelet engraftment (DPE) is a common complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT). This phenomenon is also a predictor of increased treatment-related mortality and poor survival. Therefore, therapies that promote platelet engraftment to prevent DPE are needed. This prospective randomized controlled trial was designed to investigate whether recombinant human thrombopoietin (rhTPO), administered subcutaneously at a daily dose of 15,000 U from the first day after transplantation, promotes platelet engraftment after haploidentical HSCT. The cumulative incidence of platelet engraftment (platelet recovery to ≥20 × 10(9)/L without transfusion support for seven consecutive days) on day 60 post-transplantation was significantly higher in the rhTPO group (n = 60) than in the control group (n = 60) (91.7 ± 3.8 % vs. 74.5 ± 5.8 %, P = 0.041). Additionally, the number of platelet transfusions from day 14 to day 60 was significantly lower in the rhTPO group than in the control group (4 ± 5 vs. 7 ± 9 Units, P = 0.018). No severe adverse effects were observed, with a median follow-up duration of 256 days (range, 48-586 days). The incidences of acute graft-versus-host disease (GVHD), chronic GVHD, and cytomegalovirus viremia and the probabilities of overall survival and disease-free survival did not differ between the two groups. A multivariate analysis of all patients revealed that regardless of assignment to the rhTPO group or the control group (hazard ratio (HR) = 1.514; 95 % CI (1.024-2.238); P = 0.038), the number of total infused CD34(+) cells (HR = 1.304; 95 % CI (1.148-1.482); P < 0.001) and slower neutrophil engraftment (HR = 2.777; 95 % CI (1.841-4.189); P < 0.001) were associated with platelet engraftment. In conclusion, rhTPO promotes platelet engraftment and safely reduces the requirement for platelet transfusion in patients after unmanipulated haploidentical HSCT. This trial was registered with the Chinese Clinical Trial Registry ( www.chictr.org ) as ChiCTR-TRC-11001774. http://www.chictr.org/cn/proj/show.aspx?proj=2132 .