Efficacy and Safety of Herombopag for the Treatment of Secondary Failure of Platelet Recovery after Allogeneic Hematopoietic Stem Cell Transplantation: the Single Center Prospective Study from China

Background Thrombocytopenia is a frequent and serious complication after Allogeneic hematopoietic stem cell transplantation (allo-HSCT). It often has a multifactorial etiology, including poor graft function, GVHD, drugs, infections, and microangiopathy. Prolonged thrombocytopenia after HSCT, which is an independent adverse prognostic factor for transplant-related mortality (TRM) and overall survival, has not yet been systematically investigated. Among then, secondary failure of platelet recovery (SFPR) is the most common type of thrombocytopenia after allo-HSCT. SFPR refers to thrombocytopenia that develops after initial platelet engraftment and is not due to graft rejection or relapse. It defined as a decline in platelet count of < 20×10 9/L for 7 consecutive days or requiring transfusion support after achieving a sustained platelet count > 50×10 9/L without transfusion for 7 consecutive days after HSCT. Methods Here, we conduct a retrospective study to the efficacy and safety of herombopag in 81 patients with SFPR after allo-HSCT. Patients were administered the following treatment regimen: 5 mg/d herombopag; if the PLT count was less than 50×10^9/L for at least 2 weeks, the dose was increased to 7.5 mg/d; if the PLT count was 200-400×10 9/L, the dose was reduced; and if the PLT count was greater than 400×10 9/L, herombopag was terminated. Results Baseline platelet count of patients before treatment is 12 (2-20)×10 9/L. The initial time of treatment is 5 (3-14) months after allo-HSCT, and the median duration of treatment is 103 (45-276) days. Among the 81 patients, 51 patients (62.9%) had complete response (CR, defined as PLT≥50×10 9/L without PLT transfusion for 7 continuous days), 9 patients (11.1%) had a partial response (PR, defined as PLT of [20-50] ×10 9/L without PLT transfusion for 7 continuous days), and 21 patient (26.0%) had no response (NR, defined as the application of the maximum tolerated dose for 8 weeks and PLT<20×10 9/L or the need for PLT transfusion). The median time to obtain CR was 49 (18-229) days after treatment. The time to reach 20×10 9/L