The U.S. Food and Drug Administration (FDA) granted approval to a supplemental new drug application for avatrombopag, expanding its use to include the treatment of adults with chronic immune thrombocytopenia (ITP) that hasn’t responded satisfactorily to a previous therapy. The drug is already approved for the treatment of thrombocytopenia in adult patients with chronic liver disease (CLD) who are scheduled to undergo an invasive procedure.
Avatrombopag is an oral, thrombopoietin receptor agonist (TPO-RA). In a phase III study of patients with ITP, avatrombopag administration resulted in a platelet count of at least 50×109/L by day eight of administration in most patients. Avatrombopag also was superior to placebo in maintaining platelet counts in the target range during the six-month treatment period. Additional supportive efficacy data for the approval were provided by two phase II trials of ITP, as well as two phase III trials for the treatment of thrombocytopenia in patients with CLD.
The most common adverse events (AEs) in patients with CLD were pyrexia, abdominal pain, nausea, headache, fatigue, and peripheral edema; the most common AEs (≥10%) in patients with ITP were headache, fatigue, contusion, epistaxis, upper respiratory tract infection, arthralgia, gingivival bleeding, petechiae, and nasopharyngitis.
Dose adjustments are advised for patients with ITP taking moderate or strong dual CYP2C9 and CYP3A4 inducers or inhibitors.