press release archive

Rigel Pharmaceuticals Presents Drug Discovery Programs in Oncology At Two Symposia

Molecular Targets for Cancer Therapy Keystone Symposia

Ubiquitin and Ubiquitin-Like Modifications in Health and Disease Conference Sponsored by the National Institutes of Health

South San Francisco, Calif. - March 21, 2003

Rigel Pharmaceuticals, Inc. (Nasdaq: RIGL) scientists will present updates of the company's drug discovery programs in the area of Ubiquitin ligases at the Molecular Targets for Cancer Therapy Keystone Symposia held March 19-24, 2003 in Banff, Alberta and at the Ubiquitin and Ubiquitin-Like Modifications in Health and Disease Conference sponsored by the National Institutes of Health held March 24-25, 2003 in Bethesda, Maryland. Ligases, a class of enzymes that regulate cell proliferation, have recently become the subject of intense interest among researchers as a potential drug target for the treatment of cancer.

"We believe that Rigel is one of the leading companies exploiting this potentially important area," said Donald G. Payan, M.D., Rigel's executive vice president and chief scientific officer. "Rigel has made significant progress in discovering drug candidates against ligase targets."

Rigel's research in the area of Ubiquitin ligases focuses on developing novel cancer therapeutics that selectively modulate the Ubiquitin-regulatory enzymes controlling oncogenic processes. Rigel believes that it has identified potent drug candidates against this class of target, and the company is currently moving them into pre-clinical evaluation.

"We believe that we are the first company to demonstrate it is possible to discover potent and selective small molecules against ligases that may be useful in oncology. We have a focused, cross-functional effort in ligases and a deep pipeline from validated targets to drug candidates." said Dr. Payan.

About Rigel Pharmaceuticals, Inc.
Rigel's mission is to become a source of novel, small-molecule drugs to meet large, unmet medical needs. Rigel has identified three lead product development programs: mast cell inhibition to treat immunologic diseases such as asthma/allergy and autoimmune disorders; antiviral agents to treat hepatitis C; and Ubiquitin ligases, a new class of cancer drug target. Rigel has begun clinical testing of its first product candidate, for the treatment of allergic rhinitis, and plans to begin clinical trials of two additional drug candidates for the treatment of hepatitis C and rheumatoid arthritis within the next 12 months. Rigel's approach to drug discovery is based on advanced, proprietary functional genomics techniques that allow the company to identify targets with a demonstrable role in a disease pathway and to screen efficiently for those that are likely to be amenable to drug modulation. The company's business model is to develop a portfolio of drug candidates and to take these through phase II clinical trials, after which Rigel intends to seek commercialization partners for completion of clinical evaluation, regulatory approval and marketing.

This press release contains "forward-looking" statements, including statements related to Rigel's business strategy, drug development programs and clinical trial plans. Any statements contained in this press release that are not statements of historical fact may be deemed to be forward-looking statements. Words such as "plans," "intends," "believes," and similar expressions are intended to identify these forward-looking statements. There are a number of important factors that could cause Rigel's results to differ materially from those indicated by these forward-looking statements, including the risks detailed from time to time in Rigel's SEC reports, including its Annual Report on Form 10-K for the year ended December 31, 2001 and Quarterly Report on Form 10-Q for the quarter ended September 30, 2002. Rigel does not undertake any obligation to update forward-looking statements.