The law firm of Lieff Cabraser Heimann & Bernstein, LLP announces that class action lawsuits have been brought on behalf of purchasers of the securities of Arena Pharmaceuticals, Inc. (“Arena” or the “Company”) (Nasdaq: ARNA) between December 8, 2008 and September 16, 2010, inclusive (“Class Period”). If you purchased Arena securities during the Class Period, you may move the Court for appointment as lead plaintiff by no later than November 19, 2010. A lead plaintiff is a representative party who acts on behalf of other class members in directing the litigation. Your share of any recovery in this action will not be affected by your decision of whether to seek appointment as lead plaintiff. You may retain Lieff Cabraser, or other attorneys, as your counsel in this action. Arena shareholders that wish to learn more about this action and how to seek appointment as lead plaintiff should visit Lieff Cabraser’s website at http://www.lieffcabraser.com/cases.php?CaseID=345 or contact attorney Sharon Lee toll free at (800) 541-7358. Background on Arena Securities Class Litigation The actions, pending in the United States District Court for the Southern District of California, were brought against Arena and certain of its officers for violations of federal securities laws. Arena, headquartered in San Diego, California, is a clinical-stage biopharmaceutical company focused on discovering, developing, and commercializing oral drugs that target G protein-coupled receptors. Arena’s principal drug under development is Lorcaserin, an experimental weight loss drug. The complaints allege that throughout the Class Period, defendants made materially false statements regarding Lorcaserin. Specifically, during the Class Period, defendants allegedly touted Lorcaserin’s purported efficacy, safety, and tolerability but failed to disclose certain health risks associated with the drug. On September 14, 2010, the Food and Drug Administration (“FDA”) issued a briefing document in advance of its advisory panel meeting that questioned the safety and efficacy of Lorcaserin and revealed, among other things, that the drug was associated with malignant tumors in rats. On this news, the price of Arena common stock fell $2.72 per share, or nearly 40 percent, to close at $4.13 per share on September 14, 2010. On September 16, 2010, the FDA advisory panel reportedly rejected Lorcaserin due to concerns with the drug’s efficacy and potential safety problems. On the following day, September 17, 2010, Arena’s stock fell another $1.75 per share, or approximately 47 percent, to close at $1.99 per share.