Rare Disease Report

FDA Accepts New Drug Application for Chronic ITP Treatment

JUNE 19, 2017
Mathew Shanley
This article has been updated from its June 19 version and now contains information from an RDR exclusive interview with Raul Rodriguez, president and chief executive officer of Rigel.

Earlier today, it was announced that the U.S. Food and Drug Administration (FDA) filed Rigel Pharmaceuticals, Inc.’s New Drug Application for the use of Tavalisse (fostamatinib disodium) for the treatment of chronic immune thrombocytopenia (ITP).
Tavalisse, an oral investigational drug candidate designed to inhibit SYK kinase, a key enzyme in the immune process that leads to platelet destruction in ITP. It was previously granted Orphan Drug designation for treatment of the same condition in April.
ITP is a bleeding disorder in which blood doesn't clot as it does typically due to an unusually low number of platelets or thrombocytes. It’s almost always chronic in adults, but is often acute and self-limited in children. Symptoms include excessive bruising and bleeding.
"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."
Data from the Phase 3 clinical program for fostamatinib in ITP supported the NDA submission and was comprised of 3 studies, 2 of which were randomized placebo-controlled studies and 1 was an open-label extension study. Across all indications (Rigel is also testing the use of fostamatinib on patients with autoimmune hemolytic anemia and IgA nephropathy), fostamatinib has been evaluated in more than 4,600 subjects, but the NDA included 163 ITP patients together with an initial proof of concept study.
Current treatment of ITP includes corticosteroids, splenectomy, immunosuppressants, and thrombopoietin receptor agonist drugs. In the event of life-threatening bleeding, platelet transfusions, IV corticosteroids, IV anti-D immune globulin, or IV immune globulin may be used individually or in combination.

"ITP is a serious and life-limiting rare disease with insufficient treatment options," said Rodriguez. "We hope, if approved, Tavalisse may provide an alternative treatment for some of these patients and their lives will be better because of it. Everything starts with a first step. We're very excited about fostamatinib and the impact that we think it can have on ITP patients."
Differentiating itself from other available therapies that modulate the immune system or stimulate production of platelets, the expected result of fostamatinib is that it will address the underlying autoimmune cause of ITP by impeding platelet destruction.

Rodriguez noted that 2 patients have been treated with fostamatinib for the past 7 years, and have shown promising signs for ITP patients in the future.
The Prescription Drug User Fee Act (PDUFA) date for the FDA to make its final decision is expected to be April 17, 2018.

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