Efficacy and Safety of Avatrombopag in the Treatment of Thrombocytopenia after Umbilical Cord Blood Transplantation

Background: Delayed platelet engraftment is a common complication after umbilical cord blood transplantation (UCBT), and it has no standard therapy. Avatromboapg is a second generation thrombopoietin receptor agonist (TPO-RA) and showed efficacy in immune thrombocytopenia (ITP). However, few reports focused on its efficacy in patients diagnosed with thrombocytopenia after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods: We conducted a retrospective study to evaluate the efficacy of avatrombopag in 69 patients after UCBT as the first-line thrombopoietin receptor agonist (TPO-RA) treatment. Results: Sixty-one patients were given avatrombopag to promote platelet engraftment, the other 8 for secondary failure of platelet recovery (SFPR). For the majority of patients (44/69, 63.8%), the initial dose was 40 mg daily. Among the 61 patients given avatrombopag for platelet engraftment, 40 achieved an overall response (OR) (65.6%), and the cumulative incidence of OR was 76.2% (95% CI, 61.3-86.0), at a median time of 23 days (range, 3-131 days). Thirty-eight of 61 (62.3%) patients achieved complete remission (CR), and the cumulative incidence of CR was 76.2% (95% CI, 61.1-86.1). Patients suffering from SFPR had a better cumulative incidence of OR [100% (95% CI, NA), P = 0.005]. Giving avatrombopag before 37 days post-UCBT was beneficial for OR in multivariate analysis. Conclusion: In summary, our results indicate that avatrombopag could be used to promote platelet engraftment, especially in the early period (< 37 days after UCBT). Patients with SFPR may have a better response to avatrombopag therapy. Keywords: Avatrombopag; umbilical cord blood transplantation; thrombopoietin receptor agonist; secondary failure of platelet recovery Conflict-of-interest disclosure: The authors declare that they have no competing interests.