Efficacy and safety of hetrombopag in the treatment of Pediatric immune thrombocytopenia: A Real-World Observational Study

Abstract Background Hetrombopag, an oral thrombopoietin receptor agonist (TPO-RA), has been approved to increase platelet counts and reduce bleeding risks in adults with immune thrombocytopenia (ITP). We conducted a prospective, observational, single-group study (ClinicalTrials.gov number, NCT06107582) to assess the efficacy and safety of hetrombopag for children with primary ITP. Methods Children aged ≥6 to <18 years with a confirmed diagnosis of primary ITP and a baseline platelet count ≤30×10⁹/L were enrolled and treated with hetrombopag at an initial dose of 5 mg or 7.5 mg once daily for up to 24 weeks. Doses were adjusted based on the platelet count. The primary efficacy endpoint was defined as the proportion of patients achieving a platelet count of ≥50×109/L within 4 weeks without rescue therapy (confirmed by two consecutive measurements at least 7 days apart). Findings A total of 11 children with ITP received hetrombopag treatment. 63.6% of (95% CI:31.1–88.1) patients met the primary efficacy endpoint within 4 weeks. Notably, 2 patients who had previous treatment failure with eltrombopag or a relapse after eltrombopag therapy also reached the primary efficacy endpoint. In this study, the median time to achieving a platelet count of ≥50×10⁹/L was 2.3 weeks [interquartile range (IQR), 1–7]. Over the 24-week study, 54.5% of the patients (95% CI:23.3–83.3) achieved sustained response with the median cumulative duration of 22 weeks [interquartile range (IQR), 2–23]. The proportion of patients with WHO bleeding scale grades 1–4 decreased from 54.5% at baseline to 9% at week 24, with only grade 1 bleeding events reported during follow-up. Among the 5 (45.5%) patients using combination medications at study entry, all successfully tapered or discontinued concomitant medications by week 24. During treatment with hetrombopag, rescue therapy was required in only 2 (18.1%) patients. The transaminase elevation reported in 1 (9.1%) patient, which resolved with medical management. No death or serious adverse events were reported. Conclusion Hetrombopag showed efficacy in elevating and sustaining platelet counts in pediatric ITP patients, with a favorable safety profile. Notably, it remained effective even in patients who had shown inadequate response to prior eltrombopag therapy.