SOUTH SAN FRANCISCO, Calif., March 20 /PRNewswire-FirstCall/ -- Exelixis, Inc. (Nasdaq: EXEL) and Sankyo Company (a wholly owned subsidiary of DAIICHI SANKYO COMPANY, LIMITED) today announced a collaboration agreement to discover, develop and commercialize novel therapies targeted against the mineralocorticoid receptor (MR), a nuclear hormone receptor (NHR) implicated in a variety of cardiovascular and metabolic diseases. Two MR antagonists have already been approved by the U.S. Food and Drug Administration for the treatment of hypertension and congestive heart failure.

Under the terms of the agreement, Exelixis will receive a $20 million upfront payment upon signing of the agreement. In addition, Exelixis is entitled to receive research funding, substantial development, regulatory and commercialization milestone payments as well as double-digit royalties on the sale of any products commercialized under the collaboration. After the joint research term, Sankyo will be responsible for all further preclinical and clinical development, regulatory, manufacturing and commercialization activities for the compounds.

"Sankyo brings important expertise in cardiovascular disease to our MR program, and we look forward to working together to develop new treatments in this area. This transaction with Sankyo is the third that we have executed around our portfolio of metabolic disease programs," said George A. Scangos, Ph.D., president and chief executive officer of Exelixis. "In total, these transactions provide us with over $70 million in guaranteed near-term payments, over $1 billion in potential development and commercialization milestones and substantial royalties on these three classes of compounds."

"MR is a validated therapeutic target for cardiovascular disease, but the safety, tolerability and efficacy profiles of currently approved MR antagonists need to be improved," said Hideyuki Haruyama, Ph.D., Corporate Officer and General Manager, Research Institute at Sankyo. "We believe that the compounds in Exelixis' MR program hold significant promise for improving the treatment of a variety of cardiovascular diseases."

About the Exelixis MR Program

MR is a member of the NHR superfamily and is expressed in a variety of tissues including kidney, heart, brain and smooth muscle. Compounds that inhibit activation of MR (antagonists) are used to treat hypertension and congestive heart failure due to their vascular protective effects. Recent studies have also shown the beneficial effects of adding MR antagonists to the treatment regimen in Type II diabetic patients with nephropathy. Exelixis has developed a series of non-steroidal, small molecule, receptor specific, potent MR antagonists with good bioavailability and an excellent pharmacokinetic profile in preclinical models that have the potential to offer therapeutic advantages over existing therapies for the treatment of hypertension, congestive heart failure and end organ protection due to vascular damage.

About Exelixis

Exelixis, Inc. is a biotechnology company dedicated to the discovery and development of novel therapeutics that will potentially enhance the care and lives of patients with cancer and other serious diseases. The company is leveraging its fully integrated gene-to-drug platform to fuel the growth of its proprietary drug pipeline. Exelixis' development pipeline covers cancer and metabolism and is comprised of the following compounds: XL119 (becatecarin), for which a multinational Phase III clinical trial in bile duct tumor is ongoing and which has been exclusively licensed to Helsinn Healthcare S.A.; XL784, which is being advanced as a treatment for renal disease and expected to enter Phase II early in 2006; XL999, an anticancer compound, currently in Phase II clinical trials for a variety of solid tumors; XL647, XL880, XL820, XL844 and XL184, anticancer compounds currently in Phase I clinical trials; and multiple compounds in preclinical development for diseases including cancer and various metabolic and cardiovascular disorders. Exelixis has established broad corporate alliances with major pharmaceutical and biotechnology companies including GlaxoSmithKline (GSK) and Bristol-Myers Squibb Company. Pursuant to a product development and commercialization agreement between Exelixis and GSK, GSK has the option, after completion of clinical proof-of-concept by Exelixis, to elect to develop a certain number of compounds in Exelixis' product pipeline, which may include XL784 and the cancer compounds identified in this press release (other than XL119), thus potentially triggering milestone payments and royalties from GSK and co- promotion rights by Exelixis. For more information, please visit the company's web site at http://www.exelixis.com .

This press release contains forward-looking statements, including without limitation all statements related to the discovery, development and commercializing of therapies targeted against MR under the collaboration agreement as well as related payments; the therapeutic and commercial potential of XL119, XL784, XL647, XL999, XL880, XL820, XL844 and XL184, other compounds in the Exelixis preclinical pipeline and its program in metabolic diseases. Words such as "believes," "anticipates," "plans," "expects," "intends," "will," "slated," "goal" and similar expressions are intended to identify forward-looking statements. These forward-looking statements are based upon Exelixis' current 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, the potential failure of product candidates to demonstrate safety and efficacy in clinical testing, including product candidates that appeared promising in early research; the ability of Helsinn Healthcare S.A. to conduct the Phase 3 clinical trial of XL119 sufficient to achieve FDA approval; the ability to complete and initiate trials at the referenced times; the ability to conduct clinical trials sufficient to achieve positive completion; the ability to file INDs at the referenced times; the ability of Exelixis to advance additional preclinical compounds into clinical development; the uncertainty of the FDA approval process; and the therapeutic and commercial value of the company's compounds. These and other risk factors are discussed under "Risk Factors" and elsewhere in Exelixis' annual report on Form 10-K for the year ended December 31, 2005 and other filings with the Securities and Exchange Commission. Exelixis expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in the company's expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based.

Exelixis and the Exelixis logo are registered U.S. trademarks. Spectrum Selective Kinase Inhibitor is a trademark of Exelixis, Inc.

SOURCE Exelixis, Inc.

CONTACT: Investor Contact: Charles Butler, Director Corporate Communications, +1-650-837-7277, cbutler@exelixis.com, Media Contact: Soleil Harrison, Manager Corporate Communications, +1-650-837-7012, sharrison@exelixis.com, both of Exelixis, Inc.
Web site: http://www.exelixis.com