The first study in this program completed enrollment at the end of January and the second study has now completed enrollment. The results from the first study are expected in the middle of 2016, with the results for the second study expected shortly thereafter.
Earlier this year Rigel initiated a Phase 2 clinical trial in a second autoimmune disorder of the blood, autoimmune hemolytic anemia (AIHA). The purpose of this clinical trial is to evaluate the safety and efficacy of fostamatinib in patients with chronic AIHA. This disorder affects an estimated 40,000 Americans, for whom no approved treatment options currently exist.
FIT Phase 3 Program of Fostamatinib in ITP
The FIT program consists of two identical studies of approximately 75 patients each. The patients have been diagnosed with persistent or chronic ITP, and have blood platelet counts consistently below 30,000 per microliter of blood.
Study subjects remain on treatment for up to 24 weeks. The primary efficacy endpoint of this program is a stable platelet response by week 24 with platelet counts at or above 50,000 per microliter of blood for at least four of the final six qualifying blood draws.
Fostamatinib and ITP
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. ITP patients can suffer extraordinary bruising, bleeding and fatigue as a result of low platelet counts. Current therapies for ITP include steroids, blood platelet production boosters (TPOs) and splenectomy. Rigel believes that fostamatinib may address the autoimmune basis of the disease.
Fostamatinib and AIHA
AIHA is a rare, serious blood disorder where the immune system produces antibodies that result in the destruction of the body’s own red blood cells. Symptoms can include fatigue, shortness of breath, rapid heartbeat, jaundice or enlarged spleen. While no medical treatments are currently approved for AIHA, physicians generally treat acute and chronic cases of the disorder with corticosteroids, other immuno-suppressants, or splenectomy. Research has shown that inhibiting SYK with fostamatinib may reduce the destruction of red blood cells.