A Potent Inhibitor of IgG Signaling:
- Immune Thrombocytopenic Purpura (ITP) is a blood disorder in which the immune system attacks and destroys platelets in the blood, resulting in an abnormally low platelet count. Rigel is focusing its ITP program on the chronic form of this disorder, targeting the underlying autoimmune cause of the disease, rather than stimulating platelet production.
- Approximately 100,000 people suffer from chronic ITP. The majority of these cases are in women.
- Antibodies, usually of the IgG type, mediate the platelet destruction in ITP. Fostamatinib has a novel mechanism of action, blocking IgG receptor signaling in both macrophages and B-cells.
Disease background and current therapeutic approaches
Immune Thrombocytopenic Purpura (ITP) is an autoimmune hematological disease whereby the immune system attacks and destroys platelets in the blood, resulting in an abnormally low platelet count that can result in easy bruising, bleeding gums and internal bleeding. There are two forms of ITP: acute thrombocytopenic purpura, which is most commonly seen in young children (2 to 6 years old) and usually does not recur; and chronic thrombocytopenic purpura, which requires continual follow up care with a hematologist.
Failure of first line medical therapy for the treatment of chronic ITP, consisting mostly of high dose steroids, can lead to a splenectomy (removal of the spleen), which poses the risk of other significant complications. There is no consensus on the appropriate management for persistent ITP, but due to the fact that sustained remission is infrequent - new therapies are needed.