Arena Pharmaceuticals, Inc.
Oct 8, 2003

Arena Pharmaceuticals Offers to Purchase Three Million Shares Owned By Its Largest Stockholder at 90% of Market Value And Amends Stockholders Agreement With the Stockholder

SAN DIEGO, Oct 8, 2003 /PRNewswire-FirstCall via COMTEX/ -- Arena Pharmaceuticals, Inc. (Nasdaq: ARNA) today announced that the Stockholders Agreement dated as of January 17, 2003, with its largest stockholder, Biotechnology Value Fund, L.P. and certain related entities ("BVF"), has been amended, and that the parties are in discussions about possibly further amending the agreement.

Arena has two offer rights under the Stockholders Agreement. Pursuant to the initial right, Arena can offer to purchase at least three million shares of Arena common stock from BVF at a cash purchase price per share representing a ten percent (10%) discount to Market Value (as defined in the Stockholders Agreement). As amended, the Stockholders Agreement provides that BVF can accept or reject this initial offer by the earlier of ten days following the notice of the offer or two business days after Arena requests a response (the Stockholders Agreement previously provided that BVF had two business days to respond). If BVF rejects the offer, Arena then has the right during the next ten business day period to make a second offer to purchase at least three million shares of Arena common stock from BVF at a price that is higher than the price offered in the first offer. If BVF accepts either the initial offer or the second offer, or if the second offer is $8.00 or more per share, the standstill under the Stockholders Agreement would be extended until December 31, 2004.

In order to protect Arena's rights under the Stockholders Agreement while discussions about possibly further amending the agreement are ongoing, Arena made the initial offer on October 7, 2003, at a price of $7.69 per share. The Market Value on October 7, 2003, was $8.54, which was the closing price of Arena's common stock on the Nasdaq Stock Market® on that day. There is no assurance as to whether BVF will accept the initial offer, whether Arena will make the second offer or whether the current discussions between Arena and BVF will result in a further amendment to the Stockholders Agreement.

The Stockholders Agreement is filed as Exhibit 10 to Arena's January 21, 2003, Form 8-K.

Arena is a biopharmaceutical company focused on discovering and developing drugs that act on an important class of drug targets called G protein-coupled receptors, or GPCRs. Arena uses its Constitutively Activated Receptor Technology, or CART, Melanophore technology and other proprietary technologies to better understand GPCRs and to identify small molecules that may lead to new drugs. Arena focuses its efforts in four therapeutic areas: metabolic diseases, cardiovascular diseases, central nervous system disorders and inflammatory diseases. Within these areas, Arena is developing a portfolio of internally discovered, highly selective small molecules for large markets with unmet medical needs, including obesity, diabetes, depression and sleep disorders.

Certain statements in this press release are forward-looking statements that involve a number of risks and uncertainties. Such forward-looking statements include statements about further discussions with BVF, a possible future amendment to the Stockholders Agreement, Arena's strategy, technologies, internal programs, future achievements, and statements that are not historical facts, including statements about our ability to identify and develop small molecules or which are preceded by the word "will" or similar words. For such statements, Arena claims the protection of the Private Securities Litigation Reform Act of 1995. Actual events or results may differ materially from Arena's expectations. Important factors that could cause actual results to differ materially from those stated or implied by Arena's forward-looking statements are disclosed in Arena's SEC reports, including Arena's most recent quarterly report on Form 10-Q. These forward-looking statements represent Arena's judgment as of the date of this release. Arena disclaims any intent or obligation to update these forward-looking statements.

Arena Pharmaceuticals® and Arena® are registered service marks of the company. CART is an unregistered service mark of the company. Arena's headquarters are at 6166 Nancy Ridge Drive, San Diego, California 92121, and its telephone number is (858) 453-7200. On the Internet, please refer to Arena's Web site at for further information.

For further information, please contact: Jack Lief, President and CEO at (858) 453-7200, ext. 223, or Joseph F. Mooney, CFO at (858) 453-7200, ext. 508

SOURCE Arena Pharmaceuticals, Inc.