Oral SYK Inhibitor for Autoimmune Hemolytic Anemia:
- Autoimmune hemolytic anemia (AIHA) is a rare, serious blood disorder in which the immune system produces antibodies that result in the destruction (hemolysis) of the body's own red blood cells (RBC).
- AIHA affects approximately 40,000 adult patients in the US and can be a severe, debilitating anemia. In AIHA, symptoms can include fatigue, pale color, rapid heartbeat, and shortness of breath. In severe cases fever, chest pain, fainting, or heart failure may occur. Mild splenomegaly (enlargement of the spleen) is typical. To date, there are no approved therapies for AIHA, despite the tremendous medical need that exists for these patients.
- Rigel's fostamatinib disodium hexahydrate (fostamatinib) is an oral spleen tyrosine kinase (SYK) inhibitor. Pre-clinical research with fostamatinib in AIHA showed that inhibiting SYK may ameliorate red blood cell destruction.
- On January 31, 2018, the FDA granted Orphan Drug designation to fostamatinib for the treatment of patients with AIHA.
- In Rigel’s SOAR Phase 2 clinical trial evaluating the safety and efficacy of fostamatinib in patients with warm AIHA who did not receive a meaningful benefit from at least one previous treatment, 9 out of 21 evaluable patients (43%) achieved the primary efficacy endpoint at week 24. One additional patient was a late responder at week 30, for a total of 10 out 21 evaluable patients (48%).
- In May 2019, Rigel enrolled the first patient in a pivotal Phase 3 clinical trial of fostamatinib in warm AIHA. The clinical trial protocol calls for approximately 80 patients in a 24-week study with topline results projected for mid-2021.