PB0671 - Management of Chronic ITP with TPO-mimetics- Single Centre Experience at Birmingham Children’s Hospital, UK.

Background: Immune thrombocytopenia (ITP) in children, marked by low platelet counts and an increased bleeding tendency, presents a diverse clinical spectrum. Delineating the three disease phases (newly diagnosed, persistent, and chronic), the majority of paediatric ITP cases are short-lived, not necessitating treatment. However, for those with increased bleeding symptoms at the time of diagnosis, short courses of steroids are recommended. Thrombopoietin receptor agonists are subsequently advised for children unresponsive to first-line treatment or who become steroid-dependent, given their established efficacy and safety profiles.

Aims: This study focuses on chronic ITP in paediatric patients, investigating the efficacy and safety of thrombopoietin receptor agonists (TPO-RAs) – eltrombopag, romiplostim, and avatrombopag.

Methods: The study presents retrospective data on 62 pediatric patients with chronic ITP who received TPO mimetics between the years 2012 and 2023.

Results: Forty patients received eltrombopag, 16 received romiplostim, and 6 received avatrombopag, with ages ranging from 2.5 to 16 years.
In the eltrombopag cohort (23 females, 17 males), 2 children exhibited no response. Among the 38 responders, 9 experienced a loss of response, while 6 successfully discontinued eltrombopag and maintained stable platelet counts. The romiplostim cohort (9 females, 6 males) featured 1 non-responder, 12 with a good response, 2 experiencing a loss of response, and 1 successfully discontinuing romiplostim. In the avatrombopag cohort (3 males, 3 females), 1 had no response, and 2 of the 5 responders required additional immunosuppressive agents.
All responders maintained platelet counts exceeding 50 x 10^9/L, with TPO mimetics demonstrating minimal side effects and high tolerability. The overall response rate was 96% (95% for eltrombopag, 87% for romiplostim, and 83% for avatrombopag).

Conclusion(s): This retrospective analysis provides crucial insights into the efficacy and safety of TPO-RAs in pediatric chronic ITP, offering valuable information for clinical decision-making in the management of this heterogeneous disorder.