South San Francisco, California
May 6, 2003

Exelixis, Inc. (Nasdaq: EXEL) today reported financial results for the quarter ended March 31, 2003.

For the quarter ended March 31, 2003, the company reported a net loss of approximately $23.1 million, or $0.39 per share, under generally accepted accounting principles (GAAP), compared to a net loss of $18.4 million, or $0.33 per share, for the quarter ended March 31, 2002. For the quarter ended
March 31, 2003, the company reported a non-GAAP net loss of approximately $22.4 million, or $0.38 per share, excluding discontinued operations and non-cash charges for stock compensation and amortization of intangibles. For the quarter ended March 31, 2002, the comparable non-GAAP net loss was approximately $17.0 million, or $0.31 per share. A reconciliation of GAAP net loss to non-GAAP net loss is set forth at the end of this press release. At March 31, 2003, cash, cash equivalents, short-term investments and restricted cash totaled approximately $203.9 million compared to $222.0 million at December 31, 2002.

For the quarter ended March 31, 2003, total revenues were approximately $12.3 million, compared to $11.5 million for the same period of 2002. The increase from 2002 to 2003 was driven primarily by revenue from our October 2002 corporate collaboration with SmithKlineBeecham Corporation (GlaxoSmithKline) partially offset by the reduction in revenue from the conclusion of our Pharmacia relationship in February 2002.

Research and development expenses for the quarter ended March 31, 2003 were $30.3 million, including stock compensation expense of $0.2 million, compared to $26.2 million, including stock compensation $0.5 million, for the equivalent period of 2002. The increase in the quarter from the 2002 levels was driven primarily by an increase in personnel costs and activities related to advancing our clinical and preclinical development programs. These activities included: completing regulatory toxicology testing of XL784 and successfully filing the IND application at the end of the quarter; advancing a new series of development candidates and back-up compounds into preclinical testing in anticipation of filing additional IND applications; manufacturing of those compounds to support preclinical studies; building additional infrastructure in clinical development to support an expanding clinical pipeline; and completion of the manufacturing of XL119, our rebeccamycin analogue, to support initiation of registration trials later in 2003. General and administrative expenses for the quarter ended March 31, 2003 were $5.2 million, including stock compensation expense of $0.2 million, compared to $4.7 million, including stock compensation of $0.3 million, for the equivalent period of 2002.

"We delivered a strong and productive quarter with respect to our financial and research and development goals," said George A. Scangos, PhD., president and chief executive officer. "The highlight of the quarter was the successful filing of our company's first IND application for a proprietary
compound, XL784. We believe that this was an important step in our maturation and evolution into a product-focused company. We believe that XL784 will be the first of many promising compounds to emerge from our gene-to-drug discovery platform that advance into the clinic, enabling us to fuel our
pipeline growth and fulfill our obligations to our partners as well as our internal development goals. We currently have an active IND application, and we plan to initiate Phase 1 first-in-man studies in healthy volunteers in the second quarter of 2003."

Continued Dr. Scangos: "During the quarter, we also made significant progress in planning the registration program for XL119, our rebeccamycin analogue, as a potential treatment for hepatobiliary tumors. We remain on track to initiate registration trials later this year, pending conclusion of
discussions with the FDA concerning trial design. We believe we continued to perform well in all other operational areas of the company, and all of our corporate alliances are also on track. In short, we believe we are making good progress toward meeting our development, strategic and financial management goals for the year."

Outlook

The following statements are based on current expectations. These statements are forward-looking, and actual results may differ materially. Except as expressly set forth below, these statements do not include the potential impact of any mergers, acquisitions or other business combinations that may be closed or entered into after March 31, 2003. With respect to financial expectations for the second quarter of 2003 compared to the first quarter, we expect our revenues to increase in the range
of 3 to 8%. We expect our operating expenses, excluding non-cash charges, to increase by 6 to 11% as we continue to focus our efforts on preclinical and clinical activities including: initiating Phase 1 safety trials for XL784; advancing development candidates through preclinical testing with the goal of
filing additional INDs; advancing XL119, our rebeccamycin analogue, into registration trials; and as we continue to support our existing collaborations.

The split-out of our German subsidiary, Artemis Pharmaceuticals GmbH, continues to progress and we expect to complete a transaction in the second quarter. Approximately $1.0 million of expenses originally expected to be incurred in the first quarter of 2003 related to the split-out of Artemis
activities, is expected to be incurred in the second quarter due to the timing of efforts to finalize the split-out. In addition to these activities, we will continue to review our worldwide operating expenses throughout the remainder of the year considering both our research and development goals and meeting our cash burn objectives for the year.

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.