November 29, 2004

Rigel to Host Investor Briefing on December 1, 2004

SOUTH SAN FRANCISCO, Calif., Nov. 29 /PRNewswire-FirstCall/ -- Rigel Pharmaceuticals, Inc. today announced that it will host an investor briefing on Wednesday, December 1, 2004 from 10:00 a.m. to 12:30 p.m. Eastern time in New York City. Leading clinical experts and Rigel management will provide a review of the company's expanding clinical pipeline and highlight two diseases on which Rigel is focused. Interested parties can view slides and listen to a live and archived audio webcast of the presentation by going to and following the links from the Company's homepage.

At the briefing, Harold S. Nelson, M.D., Professor of Medicine in the Department of Medicine at the National Jewish Medical and Research Center, will provide an overview of current treatment issues for allergy sufferers and Ernest Brahn, M.D., Professor of Medicine and Rheumatology Program Director at the UCLA School of Medicine, will discuss treatment options for rheumatoid arthritis.

Donald G. Payan, M.D., Rigel's Chief Scientific Officer and Executive Vice President, will provide an overview of Rigel's efforts to develop small molecule drug candidates to treat allergic rhinitis, hepatitis C virus (HCV), rheumatoid arthritis and cancer. In addition, Dr. Payan will outline next steps in Rigel's HCV clinical trial program.



James M. Gower

James M. Gower is Chairman of the Board and Chief Executive Officer of Rigel Pharmaceuticals, Inc. Mr. Gower has over 25 years of biotechnology experience as a senior executive at various companies including Genentech and Tularik. Mr. Gower also serves on the board of directors of Cell Genesys, Inc.


Harold S. Nelson, M.D., Professor, National Jewish Medical Center

Dr. Nelson is currently Professor of Medicine in the Department of Medicine at the National Jewish Medical and Research Center and at the University of Colorado Health Science Center in Denver, Colorado. He is a well-known speaker on allergy and asthma and is author of more than 200 articles in peer-reviewed medical journals. Dr. Nelson received the Distinguished Clinician Award from the American Academy of Allergy, Asthma, and Immunology in 1996.


Ernest Brahn, M.D., Professor of Medicine, Department of Rheumatology,

UCLA School of Medicine

Dr. Brahn runs a biomedical research laboratory in molecular immunology as well as a clinical research program primarily focused on the treatment of rheumatoid arthritis. He is currently the Web Editor for the American College of Rheumatology and Chair of the Electronic Technologies Committee. At the UCLA Medical Center, Dr. Brahn is also the Chair of the Clinical Laboratories Executive Committee and Director of the Rheumatology Training Program.


R803: Hepatitis C; R406: Rheumatoid Arthritis; R763: Oncology; and Future

Product Candidates

Donald G. Payan, M.D.

Dr. Payan is Executive Vice President and Chief Scientific Officer of Rigel Pharmaceuticals. He is one of Rigel's co-founders and a member of the Board of Directors. Dr. Payan has held senior level positions at numerous biotechnology companies, including AxyS Pharmaceuticals, Inc. and Khepri Pharmaceuticals, Inc. He is also an Adjunct Professor of Medicine at the University of California, San Francisco and is Board Certified in allergy and anti-infectives.

About Rigel (

Rigel's mission is to become a source of novel, small-molecule drugs to address large, unmet medical needs. We have initiated four development programs: asthma/allergy, hepatitis C, rheumatoid arthritis and oncology. Rigel has begun clinical testing of its first two product candidates, R112 for allergic rhinitis, which has completed a Phase II clinical trial, and R803 for hepatitis C. We expect to begin clinical trials of R406 for the treatment of rheumatoid arthritis by the end of 2004, to be followed by the anticipated initiation of clinical trials with additional product candidates for indications in oncology and asthma.

Forward Looking Statements

This press release contains "forward-looking" statements, including statements related to Rigel's plans for the clinical development of product candidates and the timing thereof and the potential efficacy of product candidates. 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 "will,""plans,""intends,""expects" 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 associated with the timing and success of clinical trials and the commercialization of product candidates, as well as other risks detailed from time to time in Rigel's SEC reports, including its Quarterly Report on Form 10-Q for the quarter ended September 30, 2004. Rigel does not undertake any obligation to update forward-looking statements.

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Rigel Pharmaceuticals, Inc.

CONTACT: Raul Rodriguez of Rigel, +1-650-624-1302; or Media, MelindaBagatelos, or Ayanna Anderson, +1-415-512-0770, or [email protected], bothfor Rigel

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