Efficacy and Safety of Avatrombopag in the Treatment of Thrombocytopenia After Haplo-HSCT

In this study, investigators aim to evaluate the efficacy of avatrombopag in thrombocytopenic patients after haploidentical hematopoietic stem cell transplantation (haplo-HSCT) through a prospective, multi-center, double-blinded, randomized placebo-controlled clinical trial.

Thrombocytopenia is a common and severe complication after haplo-HSCT, including primary isolated thrombocytopenia (PIT) and secondary failure of platelet recovery (SFPR), which may cause bleeding and infection, and thus influence the OS, DFS, and NRM of the patients. Avatrombopag has been proved effective and safe in patients with chronic liver disease(CLD) and immune thrombocytopenia (ITP) and have been approved for CLD-associated thrombocytopenia undergoing elective invasive procedure (FDA\&NMPA) and ITP(FDA). Chinese consensus has recommended avatrombopag and some other thrombopoietin receptor agonists (TPO-RAs) to treat thrombocytopenia after haplo-HSCT. However, it lacks prospective studies to support that.Investigators aim to evaluate the efficacy of avatrombopag in thrombocytopenic patients after haplo-HSCT through a prospective, multi-center, double-blinded, randomized placebo-controlled clinical trial. The patients with PLT\<20×10\^9/L or transfusion dependent on the 7th day (+D7) after haplo-HSCT are included and assigned in a 1:1 randomization schedule to the avatrombopag group (receiving avatrombopag, n=71）and the placebo group (receiving placebo, n=71). The primary endpoint is the proportion of participants whose PLT≥50×10\^9/L on +D60 after haplo-HSCT without the need for PLT transfusion for 7 consecutive days or above. Second endpoints includ the proportion of participants whose PLT≥100×10\^9/L on +D60 after haplo-HSCT without the need for PLT transfusion for 7 consecutive days or above, the proportion of participants whose PLT≥20×10\^9/L and whose PLT≥50×10\^9/L on +D30 after haplo-HSCT without the need for PLT transfusion for 7 consecutive days or above, the proportion of participants whose PLT≥50×10\^9/L and whose PLT≥100×10\^9/L on +D90 after haplo-HSCT without the need for PLT transfusion for 7 consecutive days or above, the first day to achieve PLT≥20×10\^9/L and PLT≥50×10\^9/L and PLT≥100×10\^9/L without the need for PLT transfusion for consecutive 7 days and above within +D60 after haplo-HSCT, the percentage of participants who need PLT transfusion and the average count of PLT from +D7 to + D60 after haplo-HSCT, the first day and the percentage of participants to achieve absolute neutrophil≥500/μL for consecutive 3 days within +D30 after haplo-HSCT, the graft-versus-host disease(GVHD), infection, the overall survival(OS),the disease free survival(DFS) and the non-relapse mortality(NRM) rates of participants within the first year after haplo-HSCT.