Carlsbad, CA -June 11, 2002 - Isis Pharmaceuticals, Inc. (NASDAQ: ISIS) announced today that Spencer R. Berthelsen, M.D., F.A.C.P., has been elected to the company's Board of Directors. Dr. Berthelsen is Chairman of the Board of the Kelsey-Seybold Clinic in Houston, Texas.

"We are very pleased to have Spencer join our experienced Board. He comes to Isis with a vast amount of experience and expertise in the areas of clinical management and managed care. We will look to him to help guide Isis as it creates a new sector of the pharmaceutical industry based on antisense technology," said Stanley T. Crooke, M.D., Ph.D., Isis' Chairman and CEO.

Dr. Berthelsen has been with the Kelsey-Seybold Clinic since 1980, and has held a range of positions during his tenure there including, Chief, Section of General Medicine (1982-1998); Associate Director for Maxicare, Texas (1985-1988); Medical Director for Primary and Managed Care (1991-1994); Chairman, Department of Internal Medicine (1994-1998); Member, Executive Board (1989-1992), and Medical Director of Managed Care (1994-2001).

Dr. Berthelsen currently serves as a Clinical Associate Professor of Medicine at the Baylor College of Medicine and as Clinical Professor of Internal Medicine at the University of Texas Health Science Center at Houston. Additionally, he serves as Chief, Section of General Medicine and as Associate Chief of the Internal Medicine Service at St. Luke's Episcopal Hospital. Dr. Berthelsen has served as a member of the Caremark National Pharmacy and Therapeutics Committee. During the course of his career, Dr. Berthelsen has authored several peer-reviewed papers on hypertension and has received numerous awards. He is an active member of several Texas state and national professional medical associations.

Dr. Berthelsen received his medical degree from Southwestern Medical School in Dallas, and completed his residency in internal medicine at the University of California, San Diego, University Hospital.

Isis Pharmaceuticals, Inc. is exploiting its expertise in RNA to discover and develop novel human therapeutic drugs. The company has commercialized its first product, Vitravene® (fomivirsen), to treat CMV-induced retinitis in AIDS patients. In addition, Isis has 13 antisense products in its development pipeline with two in late-stage development and six in Phase II human clinical trials. Affinitac™, an inhibitor of PKC-alpha, is in Phase III trials for non-small cell lung cancer, and alicaforsen (ISIS 2302), an ICAM-1 inhibitor, is in a Phase III trial in Crohn's disease. Isis has a broad patent estate as the owner or exclusive licensee of more than 900 issued patents worldwide. Isis' GeneTrove™ division uses antisense to assist pharmaceutical industry partners in validating and prioritizing potential gene targets through customized services. Ibis Therapeutics™ is a division focused on the discovery of small molecule drugs that bind to RNA. Additional information about Isis is available at www.isispharm.com.

This press release contains forward-looking statements concerning Isis Pharmaceuticals' research, drug discovery, drug development and functional genomics programs. Any statement describing a goal, expectation, intention or belief of the Company is a forward-looking statement and should be considered an at-risk statement. Such statements are subject to certain risks and uncertainties, particularly those inherent in the process of discovering, developing and commercializing drugs that are safe and effective for use as human therapeutics and financing such activities. Actual results could differ materially from those projected in this release. As a result, the reader is cautioned not to rely on these forward-looking statements. These and other risks concerning Isis' research and development programs are described in additional detail in the Company's Annual Report on Form 10K, for the period ended December 31, 2001, which is on file with the U.S. Securities and Exchange Commission, copies of which are available from the Company.

Vitravene® is a registered trademark of Novartis AG.
GeneTrove™ and Ibis Therapeutics™ are trademarks of Isis Pharmaceuticals, Inc.
Affinitac™, a trademark of Eli Lilly and Company, is an investigational cancer compound being developed through an alliance between Lilly and Isis Pharmaceuticals, Inc. and marketed globally by Lilly.