Rigel Pharmaceuticals announced the U.S. Food and Drug Administration (FDA) has filed its New Drug Application (NDA) for the use of Tavalisse (fostamatinib disodium) in patients with chronic or persistent immune thrombocytopenia (ITP). Rigel expects the action date for the FDA to complete its review will be April 17, 2018, under the Prescription Drug User Fee Act (PDUFA). The FDA previously granted Orphan Drug designation to Tavalisse for the treatment of patients with ITP.

"The FDA acceptance for filing of our NDA is an exciting milestone for Rigel," said Raul Rodriguez, Rigel's president and chief executive officer. "If approved, we believe Tavalisse will provide a new treatment option for patients with chronic or persistent ITP. We look forward to working closely with the FDA as they review our submission."

The NDA submission is supported by data from the Phase 3 clinical program for fostamatinib in ITP, which was comprised of three studies, two randomized placebo-controlled studies (Studies 047 and 048), and an open-label extension study (Study 049). Together with an initial proof of concept study, the NDA included 163 ITP patients. Across all indications, fostamatinib has been evaluated in over 4,600 subjects. Data from all studies, including preclinical evaluation and drug manufacturing data, were included in the NDA submission.

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 increased risk of severe bleeding events that can result in serious medical complication, or even death. Currently approved therapies for ITP include steroids, blood platelet production boosters (TPO-RAs) and splenectomy. However, not all patients derive a benefit from existing therapies. As a result, there remains a significant medical need for additional treatment options for patients with ITP.