Positive results from the Fostamatinib in Thrombocytopenia (FIT) Phase 3 clinical program of fostamatinib disodium hexahydrate (Tavalisse) were published in the American Journal of Hematology this week for the treatment of adults with chronic immune thrombocytopenia (ITP). The study, Fostamatinib for the Treatment of Adult Persistent and Chronic Immune Thrombocytopenia: Results of Two Phase 3, Randomized, Placebo-Controlled Trials, is available on the journal website.
In patients with ITP, the immune system attacks and destroys the body’s own blood platelets, which play an active role in blood clotting and healing. Common symptoms of ITP are excessive bruising and bleeding. People suffering with chronic ITP may live with an increased risk of severe bleeding events that can result in serious medical complications or even death.
The FDA approved Tavalisse on April 17 of this year for the treatment of thrombocytopenia in adult patients with chronic immune thrombocytopenia (ITP) who have had an insufficient response to a previous treatment. “These data demonstrate that Tavalisse offers the potential for a rapid, robust and durable platelet response, which is why we are excited to soon make it available to the population of patients in need of alternate treatment options,” said Anne-Marie Duliege, MD, Chief Medical Officer of Rigel Pharmaceuticals. “Tavalisse is the first approved treatment option that targets the SYK pathway, which is the main pathway involved in platelet destruction in ITP.”
FIT-1 and FIT-2 were randomized, double-blind, placebo-controlled phase 3 trials evaluating Tavalisse, an oral spleen tyrosine kinase (SYK) inhibitor, in comparison with placebo in a total of 150 adult patients with persistent or (predominantly) chronic ITP. The studies were designed in accordance with FDA guidance and the efficacy endpoints were based on an objective laboratory assessment of platelet count. Patients who completed the 24-week study treatment in either FIT-1 or FIT-2 could enroll in the long-term, open-label extension study (FIT-3); non-responders who discontinued the study after 12 weeks for lack of efficacy and had received 150 mg BID of study drug for ≥4 weeks could also enroll in FIT-3. These phase 3 studies were the first to evaluate second- or third-line treatment for ITP in the current era of widespread use of TPO-RA and rituximab.