Robbins Geller Rudman & Dowd LLP (“Robbins Geller”) ( http://www.rgrdlaw.com/cases/arena/) today announced that a class action has been commenced in the United States District Court for the Southern District of California on behalf of purchasers of Arena Pharmaceuticals, Inc. (“Arena”) (NASDAQ:ARNA) common stock during the period between December 8, 2008 and September 16, 2010 (the “Class Period”).

If you wish to serve as lead plaintiff, you must move the Court no later than 60 days from September 20, 2010. If you wish to discuss this action or have any questions concerning this notice or your rights or interests, please contact plaintiff’s counsel, Darren Robbins of Robbins Geller at 800/449-4900 or 619/231-1058, or via e-mail at djr@rgrdlaw.com. If you are a member of this class, you can view a copy of the complaint as filed or join this class action online at http://www.rgrdlaw.com/cases/arena/. Any member of the putative class may move the Court to serve as lead plaintiff through counsel of their choice, or may choose to do nothing and remain an absent class member.

The complaint charges Arena and certain of its officers and directors with violations of the Securities Exchange Act of 1934. Arena is a clinical-stage biopharmaceutical company focused on discovering, developing and commercializing oral drugs that target G protein-coupled receptors. The Company’s principal drug in development is lorcaserin hydrochloride (“Lorcaserin”), an experimental weight loss drug that has completed a pivotal Phase III clinical trial program.

The complaint alleges that during the Class Period, defendants issued materially false and misleading statements regarding Lorcaserin. Defendants continuously hyped Lorcaserin’s combination of efficacy, safety and tolerability and its potential for success without disclosing certain health risks associated with the drug. As a result of defendants’ false statements, Arena’s stock traded at artificially inflated prices during the Class Period, reaching a high of $7.95 per share on July 30, 2010.

On September 14, 2010, the Food and Drug Administration (“FDA”) issued a briefing document in advance of its advisory panel meeting in which the agency questioned both the safety and efficacy of Lorcaserin. The market price of Arena common stock fell $2.72 per share on this news to close at $4.13 per share on September 14, 2010 – a one-day decline of 40% on high volume. Then, on September 16, 2010, the FDA advisory panel voted 9 to 5 against approval of Lorcaserin, in large part because of the results of rat carcinogenicity studies, which included carcinogenicity signals in the form of mammary tumors, and the modest therapeutic benefits associated with Lorcaserin. On this news, Arena’s stock fell another $1.75 per share to close at $1.99 per share on September 17, 2010 – a one-day decline of over 46% and a 75% decline from the stock’s Class Period high.

Plaintiff seeks to recover damages on behalf of all purchasers of Arena common stock during the Class Period (the “Class”). The plaintiff is represented by Robbins Geller, which has expertise in prosecuting investor class actions and extensive experience in actions involving financial fraud.

Robbins Geller, a 180-lawyer firm with offices in San Diego, San Francisco, New York, Boca Raton, Washington, D.C., Philadelphia and Atlanta, is active in major litigations pending in federal and state courts throughout the United States and has taken a leading role in many important actions on behalf of defrauded investors, consumers, and companies, as well as victims of human rights violations. The Robbins Geller Web site ( http://www.rgrdlaw.com) has more information about the firm.

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