Avatrombopag successful in children with chronic ITP

Avatrombopag proved to be an efficacious and well-tolerated agent to treat paediatric participants with chronic immune thrombocytopenia (ITP) in the phase 3 AVA-PED-301 trial. Moreover, avatrombopag’s ease of use helps to reduce the treatment burden.

The thrombopoietin receptor agonist avatrombopag was tested in the phase 3 AVA-PED-301 trial (NCT04516967) among paediatric participants with chronic ITP who had an insufficient response to prior therapies. “The agent can be administered orally with food, has no substantial hepatotoxicity, and comes with a low immunogenicity risk compared with parenterally administered agents,” explained Dr Rachael Grace (Harvard Medical School, MA, USA) [1].

Participants (n=75) were randomised 3:1 to avatrombopag or a placebo for 12 weeks. The primary efficacy endpoint was a durable platelet response, defined as achieving ≥50*10⁹ platelets/L in 6 out of 8 weekly platelet counts without rescue therapy during the last 8 weeks of the treatment period. The alternative primary efficacy endpoint was a platelet response, which comprised at least 2 consecutive platelet assessments ≥50*10⁹ platelets/L during the 12-week treatment period without rescue therapy.

The primary efficacy endpoint was met by 27.8% of the participants in the avatrombopag arm and none in the placebo arm (P=0.0077). The alternative primary efficacy endpoint also favoured the avatrombopag arm (81.5% vs 0%; P<0.0001). The proportion of participants requiring rescue therapy was higher in the placebo arm than in the active arm (42.9% vs 7.4%; P=0.0008).

Dr Grace highlighted that the incidence of treatment-emergent adverse events was somewhat higher in the experimental arm than in the control arm (92.6% vs 76.2%), with the most common side effects being petechiae, epistaxis, ecchymosis, and headache. “We did not see any thromboembolic events during the study,” added Dr Grace.

“Avatrombopag demonstrated to be efficacious and well-tolerated in children with chronic ITP who did not respond adequately to previous treatments,” summarised Dr Grace. “The ease of oral dosing and the absence of dietary restrictions are additional advantages of this agent regarding monitoring and administration.”

1. Grace RF, et al. A phase 3, randomised, double-blind, placebo-controlled trial to evaluate the efficacy and safety of avatrombopag for the treatment of children with chronic immune thrombocytopenia (AVA-PED-301). S318, EHA congress 2024, 13–16 June, Madrid, Spain.

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Posted on 12 August 202412 August 2024