Hetrombopag for patients with persistent primary immune thrombocytopenia: A post-hoc analysis of a multicenter, randomized phase Ⅲ Trial

Abstract

Abstract Introduction: Hetrombopag has been approved for chronic primary immune thrombocytopenia (ITP) (duration >12 months). However, its efficacy and safety in persistent ITP (duration 3–12 months) remain unexplored. Based on existing clinical data, this post-hoc analysis aimed to evaluate the efficacy and safety of hetrombopag in persistent ITP patients and compare outcomes with chronic ITP and overall ITP patients. Methods: Data were derived from a registration phase Ⅲ trial (NCT03222843) which included a 10-week randomized, double-blind, placebo-controlled treatment period (initial dose: hetrombopag 2.5 mg as HETROM-2.5 group, hetrombopag 5.0 mg as HETROM-5.0 group, or placebo once daily), a 14-week open-label treatment period, a dose-tapering to withdrawal period and a 24-week single-arm extension period. The primary endpoint was the proportion of responders (a platelet count of ≥ 50×10⁹/L) after 8 weeks of treatments. Results: Of 395 who completed the double-blinded treatment, 80 patients had persistent ITP. The proportion of persistent ITP patients who achieved primary endpoint was 68.8% in the HETROM-2.5 group and 74.3% in the HETROM-5.0 group, significantly higher than 7.7% in the placebo group. Hetrombopag also demonstrated other therapeutic benefits over placebo including reduced bleeding risk and rescue therapy need. Similar efficacy results were observed both in the chronic ITP and the overall ITP population. Furthermore, hetrombopag manifested favorable safety profile in persistent ITP patients, and safety outcomes were comparable to those in chronic and overall ITP populations. Conclusions: Hetrombopag indicated favorable safe and efficacy performance in patients with persistent ITP, aligning with results observed in chronic ITP and overall ITP patients.