Rigel Pharmaceuticals will assume development of R343, its inhaled syk inhibitor for allergic asthma that recently completed several phase I clinical trials. Pfizer is returning full rights to the R343 program as a result of its decision to exit the allergy and respiratory therapeutic area within R&D.  Rigel is evaluating the details of R343's development to date and expects to design a phase II clinical trial with R343 later this year.

"It is rare in our business that one has the opportunity to develop an asset which is both promising and on which the research and development has been as well done as the package that Pfizer is transferring to us.

R343 will now become Rigel's most advanced in-house project," said James M. Gower, chairman and chief executive officer of Rigel. "The introduction of a therapeutic that would target a possible underlying cause of allergic asthma, such as R343's inhibition of syk in the immune cascade, may provide a significant advancement in the treatment of this disorder."