Rigel Pharmaceuticals Inc has initiated a multi-dose safety trial of R112, an experimental drug to treat allergic rhinitis. The goal of this trial is to establish the longer-term, multi-dose safety of R112 in various dosing regimens. Results of this trial are expected by January 2004 and will allow Rigel to enter into broader, longer-term, multi-dose efficacy trials in the first half of 2004.

In late July, Rigel released the results of a Phase I/II study which evaluated the efficacy and safety of a single intra-nasal administration of R112 in volunteers with asymptomatic seasonal allergic rhinitis. The study demonstrated significant improvement or consistent positive trends in reducing the release of chemical mediators involved in mast cell activation, one of the earliest steps in the initiation of an inflammatory response in allergy and asthma. Additionally, with only a single dose of R112, a correlation between reductions in key mediators and improvements in some allergy symptoms was established. No clinically significant adverse effects were attributed to R112 during this trial or any prior clinical trial.

"R112 may offer a new, comprehensive treatment strategy for allergic inflammation by potentially blocking all major chemical mediators of inflammation involved in mast cell responses and may provide an important, potentially first-line drug, for the treatment of allergic rhinitis," said Donald Payan, Rigel's Chief Scientific Officer and Executive Vice President.