Rigel Announces Initiation of Phase 1 Clinical Trial of R343 for Allergic Asthma by its Part...( SOUTH SAN FRANCISCO Calif. Dec. 6...),Health

SOUTH SAN FRANCISCO, Calif., Dec. 6 /PRNewswire-FirstCall/ -- Rigel Pharmaceuticals, Inc. (Nasdaq: RIGL) today announced that its corporate partner, Pfizer (NYSE: PFE), 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
'/>"/>