R343 - asthma

• Rigel's R343 is an inhaled syk kinase inhibitor designed to block the major pathways triggered by asthma, potentially resulting in a more effective and comprehensive drug.


• About 25 million people in the U.S. suffered from asthma in 2009 (8% of the population) (source: CDC).


• R343 has completed Phase 1 clinical trials for asthma. Rigel is currently planning to initiate a Phase 2 clinical trial in mid-2012.

• Rigel Announces Fourth Quarter and Year End 2011 Financial Results


• Rigel Assumes Development Responsibility for Inhaled Asthma Therapy

Asthma and Syk background
Allergic asthma is a chronic inflammatory disorder of the lungs and respiratory passages caused in response to an allergen or pathogen. In patients with this disorder, allergens, such as pollen, trigger the production of immunoglobulin E (IgE) antibodies, which then bind to mast cells (the body's defense system gatekeeper) and spark a cascade of intracellular signals to mount an immune response resulting in swelling and inflammation of the airways.

Syk is a protein tyrosine kinase that plays a pivotal role in IgE receptor signaling in mast cells. Rigel’s R343 is designed to bind to the syk in mast cells to interrupt the signal from the IgE receptors. R343’s ability to inhibit syk potentially prevents or stops the immune response to the allergen and may be effective in the short and long-term control of allergic asthma. R343 is delivered into the lung via the inhalation route.