Rigel Initiates Clinical Trial For Allergic Asthma
Pfizer has begun a Phase 1 clinical trial of an inhaled formulation of Rigel's small molecule syk kinase inhibitor, R343, for the treatment of allergic asthma. R343 is the third product candidate in Rigel's clinical portfolio.
Under the terms of the companies' 2005 collaboration agreement, Rigel will receive a $5 million milestone payment from Pfizer for the commencement of this study. Pfizer retains exclusive rights to R343 and is responsible for its clinical development.
"Developing an inhaled drug product that may address an important pathway in the allergic response causing asthmatic airway obstruction and tissue damage gives new hope to millions of asthma sufferers," stated Donald G. Payan, M.D., executive vice president and chief scientific officer of Rigel. "We are proud to have Pfizer lead the development of R343."
Syk Kinase Inhibition in Allergic Asthma
Allergic asthma is a chronic inflammatory disorder of the airways resulting in airway obstruction. In some patients, allergens, such as pollen, trigger the production of immunoglobulin E (IgE) antibodies, which then bind to mast cells and transmit intracellular signals causing the allergic response. In May 2006, Pfizer selected R343 for advanced preclinical development aimed at inhibiting IgE receptor signaling in respiratory tract mast cells by blocking the activation of syk kinase.
R343 will be delivered via the inhaled route using a dry powder inhaler and will initially be tested in healthy volunteers to evaluate its safety, dosing and pharmacodynamics. R343 is not orally bio-available and is a different molecule from R788. R788 is an orally bio-available syk kinase inhibitor in development by Rigel for various autoimmune and hematological indications and is not part of this collaboration.