About the CollaborationExelixis discovered cobimetinib (GDC-0973/XL518) internally and advanced the compound to investigational new drug (IND) status. In late 2006, Exelixis entered into a worldwide co-development agreement with Genentech, under which Exelixis received initial upfront and milestone payments for signing the agreement and submitting the IND. Exelixis was responsible for development of cobimetinib through the end of phase 1, at which point Genentech exercised its option to further develop the compound. Exelixis is entitled to an initial equal share of U.S. profits and losses, which will decrease as sales increase, and will share equally in the U.S. marketing and commercialization costs. Exelixis is eligible to receive royalties on any sales of the product outside the United States. Exelixis has the option to co-promote in the United States. About Exelixis Exelixis is a biotechnology company committed to developing small molecule therapies for the treatment of cancer. Exelixis is focusing its proprietary resources and development efforts exclusively on COMETRIQ® (cabozantinib). Exelixis has also established a portfolio of other novel compounds that it believes have the potential to address serious unmet medical needs, many of which are being advanced by partners as part of collaborations. For more information, please visit the company's web site at www.exelixis.com. Forward-Looking Statements This press release contains forward-looking statements, including, without limitation, statements related to: the continued development and clinical and therapeutic potential of cobimetinib (GDC-0973/XL518); the potential benefit of the investigational combination of cobimetinib and vemurafenib to BRAFi-naïve patients; the belief that cobimetinib warrants further study in melanoma; developments with respect to coBRIM, including the expected availability of top-line data therefrom; the designs, plans and goals for BRIM7; the plan of Genentech and Exelixis to share U.S. profits and losses for cobimetinib and U.S. marketing and commercialization costs for cobimetinib; Exelixis' potential receipt of royalties for cobimetinib products sales outside the United States; and Exelixis’ option to co-promote in the United States. Words such as “ongoing,” “suggest,” “promising,” “believe,” “warrants,” “further,” “new,” “currently,” “enrolling,” “expected,” “available,” “designed,” “entitled,” “share,” “will,” “potential,” and similar expressions are intended to identify forward-looking statements. These forward-looking statements are based upon Exelixis' current plans, assumptions, beliefs and expectations. Forward-looking statements involve risks and uncertainties. Exelixis' actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation: risks related to the potential failure of cobimetinib to demonstrate safety and efficacy in clinical testing; the availability of data at the expected times; the clinical, therapeutic and commercial value of cobimetinib; Exelixis' dependence on its relationship with Genentech/Roche and Exelixis’ ability to maintain its rights under the collaboration; the uncertainty of regulatory approval processes; market competition; and changes in economic and business conditions. These and other risk factors are discussed under “Risk Factors” and elsewhere in Exelixis' quarterly report on Form 10-Q for the three months ended June 28, 2013, filed with the Securities and Exchange Commission (SEC) on August 6, 2013, and Exelixis' other filings with the SEC. Exelixis expressly disclaims any duty, obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in Exelixis' expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based.