South San Francisco, California
June 10, 2003

Exelixis, Inc. (Nasdaq: EXEL) announces that Steven P. James has been appointed senior vice president, commercial operations. In this new position, Mr. James will be responsible for managing and expanding the company's business development and corporate development activities, and developing a strategy for pre-commercial and commercial operations. He will report directly to George A. Scangos, Ph.D., president and chief executive officer.

Mr. James has over 20 years of biotechnology and pharmaceutical experience. He joins Exelixis from Sunesis Pharmaceuticals, where he served most recently as chief business officer. In addition to building the company's highly successful business and corporate development program and establishing several large pharmaceutical alliances, Mr. James was responsible early on for developing Sunesis' operating plan, establishing strategic planning and financial management systems, as well as playing a key role in successful private financings and serving as an early member of the board of directors. Prior to Sunesis, Mr. James was vice president, business development at Isis Pharmaceuticals where he was responsible for a broad range of partnering activities and cultivating new strategic opportunities for the company.

Mr. James previously held business development, marketing and operational management positions with Landec Corporation, California Biotechnology (Scios Inc.) and Eli Lilly & Company. He holds a Bachelor's degree in biology/neuroscience from Brown University and a Master's degree in management, marketing and healthcare management from Northwestern University, Kellogg School of Management.

"Steve joins Exelixis at a very exciting period in our evolution as a product-focused company, and he will be instrumental in expanding our business operations and strategies," said Dr. Scangos. "Exelixis has successfully implemented an aggressive and creative corporate partnering strategy, and has
established several important, broadly enabling collaborations that have accelerated our growth and increased the productivity of our drug discovery and development efforts. As our development pipeline expands and matures, and as we continue to strengthen and focus our pharmaceutical business, Steve's proven track record in identifying new business opportunities and cultivating and structuring R&D partnerships, combined with his broad operational management and commercial experience, will add to the depth and breadth of our executive team. We welcome him as a colleague."

Exelixis, Inc. is a leading genomics-based drug discovery company dedicated to the discovery and development of novel therapeutics. The company is leveraging its fully integrated gene-to-drug platform to fuel the growth of its proprietary drug pipeline. Exelixis has established broad corporate alliances with major pharmaceutical and biotechnology companies, including GlaxoSmithKline, Bristol-Myers Squibb, and Protein Design Labs. The company has also established agricultural research collaborations with Bayer CropScience, Dow Agrosciences and Renessen. Other partners include Merck, Schering-Plough Research Institute, Cytokinetics, Elan and Scios.

Exelixis and the Exelixis logo are registered U.S. trademarks.