The U.S. Food and Drug Administration (FDA) has accepted Sobi North America's supplemental New Drug Application (sNDA) for avatrombopag (DOPTELET®) for the treatment of thrombocytopenia in pediatric patients one year and older with persistent or chronic immune thrombocytopenia (ITP) who have had an insufficient response to a prior therapy. The FDA has set a Prescription Drug User Fee Act (PDUFA) target action date of July 24, 2025.
Sobi's New Drug Application (NDA) for avatrombopag for oral suspension has also been accepted. The oral suspension formulation is designed as a capsule with granules that can be sprinkled onto soft food or liquid for easier administration.
Clinical Trial Data
The application is based on the results of the AVA-PED-301 study, which evaluated the efficacy and safety of avatrombopag in pediatric patients with ITP of at least 6 months' duration. The study met its primary endpoint, demonstrating a durable platelet response, defined as the proportion of patients achieving at least six out of eight weekly platelet counts ≥50x109/L during the last eight weeks of the 12-week treatment period in the core phase, without the need for rescue medication. The alternative primary efficacy endpoint of two consecutive platelet counts ≥50x109/L was also met.
Addressing Unmet Needs in Pediatric ITP
"These application acceptances for avatrombopag brings us one step closer to much-needed, additional treatment options for adolescents and children with persistent and chronic ITP," said Jamie Freedman, MD, PhD, Chief Medical Officer, Sobi North America. "Now, there's an opportunity to address an unmet need in our pediatric population, with the added bonus of an additional formulation, an oral suspension option that may be more suitable for some patients."
About Immune Thrombocytopenia (ITP)
Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by low platelet counts, leading to an increased risk of bleeding. Symptoms vary widely and can include bruising, petechiae (small hemorrhages), bleeding from the gums or nose, blood in urine/stools, and fatigue. It is estimated that up to 100 people per million live with ITP. The disorder is considered chronic when symptoms persist for more than 12 months. Long-term, primary chronic ITP is associated with increased risks of infections, bleeding episodes requiring hospitalization, hematologic malignancies, and mortality. Currently, there is no cure, and patients with chronic ITP often relapse after various treatments, requiring ongoing management to reduce the risk of clinically significant bleeding.
About Avatrombopag (DOPTELET®)
Avatrombopag (DOPTELET®) is an orally bioavailable, small molecule thrombopoietin receptor agonist (TPO-RA) that stimulates the proliferation and differentiation of megakaryocytes from bone marrow progenitor cells, resulting in increased platelet production. Avatrombopag does not compete with TPO for binding to the TPO receptor.
DOPTELET® is already indicated for the treatment of thrombocytopenia in adult patients with chronic immune thrombocytopenia who have had an insufficient response to a previous treatment.
Safety Information
DOPTELET is a thrombopoietin (TPO) receptor agonist, and TPO receptor agonists have been associated with thrombotic complications in patients with chronic liver disease (0.4%) and thromboembolic complications in patients with chronic immune thrombocytopenia (7%). Consider the potential increased thrombotic risk when administering DOPTELET to patients with known risk factors for thromboembolism, including genetic prothrombotic conditions and acquired risk factors. Monitor platelet counts and for signs and symptoms of thromboembolic events, and institute treatment promptly.
The most common adverse reactions (≥10%) in patients with chronic immune thrombocytopenia were headache, fatigue, contusion, epistaxis, upper respiratory tract infection, arthralgia, gingival bleeding, petechiae, and nasopharyngitis.
