Sobi announces positive results from phase III study of Doptelet (avatrombopag) for treatment of children and adolescents with immune thrombocytopenia

Sobi announced positive results from the AVA-PED-301 study (NCT04516967), evaluating the efficacy and safety of avatrombopag (Doptelet) for the treatment of paediatric patients with immune thrombocytopenia (ITP) of at least 6 months’ duration. The study enrolled 75 subjects between 1 and less than 18 years and the primary endpoint, durable platelet response (6 out of 8 weekly platelet counts greater than 50×109/L in the absence of rescue medication during weeks 5-12), was met in 28% of avatrombopag subjects in comparison with 0% of placebo subjects (p=0.0077, 95% CI 15.8-39.7).

The key secondary endpoint of two consecutive platelet counts greater than 50×109/L was met in 81.5% of avatrombopag subjects in comparison with 0% of placebo subjects (p=<0.0001, 95% CI 71.1-91.8). A platelet response at Day 8 was observed in 56% of avatrombopag subjects and 0% of placebo subjects (p=<0.0001), while rescue therapy use occurred in 7% of avatrombopag subjects and 43% of placebo subjects (p=0.0008). The full study results, which will be presented at an upcoming medical conference, confirm that avatrombopag could be an effective and safe oral therapy for patients between 1 and <18 years with persistent and chronic ITP who have had an insufficient response to prior therapies.

“Based on these results, I believe that avatrombopag could provide a much-needed oral treatment option for adolescents and children with persistent and chronic ITP,” said Rachael Grace, MD, MMSc, Paediatric haematologist and Director, Haematology Clinical Research at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, and lead investigator of the AVA-PED-301 study. “In this paediatric population, the lack of any food restrictions or chronic immune suppression with avatrombopag treatment would be beneficial for patients living with ITP.”

Immune thrombocytopenia (ITP) is an autoimmune disorder characterised by low numbers of platelets, leading to bruising and an increased risk of bleeding. It is estimated that up to 100 people per million live with ITP. In children, ITP occurs in 5 out of 100,000 children per year. Currently no cure is available, and patients usually relapse after various treatments yet still require treatment to reduce the risk of clinically significant bleeding.

“Considering the challenges in treatment administration, coupled with variable and transient responses, frequent relapses, and associated toxicities from existing therapies, an unmet medical need currently exists in managing ITP among children and adolescents,” said Lydia Abad-Franch, MD, MBA, Head of Research, Development, and Medical Affairs, and Chief Medical Officer at Sobi. “In line with Sobi’s mission to transform the lives of people with rare and debilitating diseases, we will continue to work towards enhancing care and addressing the distinctive challenges faced by younger ITP patients and their caregivers.”