Arena Pharmaceuticals, Inc.
Nov 2, 2005

Arena Pharmaceuticals to Present at CIBC World Markets 16th Annual Healthcare Conference

SAN DIEGO, Nov 02, 2005 /PRNewswire-FirstCall via COMTEX News Network/ -- Arena Pharmaceuticals, Inc. (Nasdaq: ARNA) announced today that it will present at the CIBC World Markets 16th Annual Healthcare Conference on Tuesday, November 8, 2005, at 3:30 p.m. Eastern Time (12:30 p.m. Pacific Time) at the Waldorf-Astoria in New York City. Jack Lief, Arena's President and Chief Executive Officer, will provide a corporate update and an overview of Arena and its clinical development and discovery programs.

A live audio webcast of the presentation will be available under the investor relations section of Arena's website at www.arenapharm.com. Replays of the presentation will be available for 30 days following the event. Please connect to Arena's website several minutes prior to the start of the conference call to ensure adequate time for any software download that may be necessary.

About Arena Pharmaceuticals

Arena is a clinical-stage biopharmaceutical company focusing on the discovery, development and commercialization of small molecule drugs in four major therapeutic areas: metabolic, cardiovascular, inflammatory and central nervous system diseases. Arena is developing a broad pipeline of compounds that act on an important class of drug targets called G protein-coupled receptors, or GPCRs, using its knowledge of GPCRs and its technologies, including CART (Constitutively Activated Receptor Technology) and Melanophore. Arena has three internally discovered, clinical-stage product candidates. Arena's most advanced clinical compound, APD356, a selective 5-HT2C serotonin receptor agonist for the treatment of obesity, is in Phase 2b. Arena's lead product candidate for the treatment of insomnia, APD125, a compound with a novel mechanism of action (a selective 5-HT2A receptor inverse agonist), is scheduled to begin a Phase 2 clinical trial by the end of 2005. As part of Arena's partnership with Merck & Co., Inc., an Arena product candidate for the treatment of atherosclerosis and related disorders is in a Phase 1 clinical trial. Arena also has an active collaboration with Ortho-McNeil, Inc., a Johnson & Johnson company, for the treatment of type 2 diabetes.

Arena Pharmaceuticals® and Arena® are registered service marks of the company. CART is an unregistered service mark of the company.

Forward-Looking Statements

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 the expected timing of Arena's Phase 2 clinical trial of APD125 and other statements about Arena's strategy, technologies, preclinical and clinical programs, and ability to develop compounds and commercialize drugs. 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. Factors that could cause actual results to differ materially from the forward-looking statements include, but are not limited to, the results of Arena's clinical trials, the results of preclinical studies or clinical trials may not be predictive of future results, Arena's ability to partner APD356, APD125 or other of its compounds or programs, the timing, success and cost of Arena's research, out-licensing endeavors and clinical trials, Arena's ability to obtain additional financing, Arena's ability to obtain and defend its patents, Arena's patent protection, and the timing and receipt of payments and fees, if any, from Arena's collaborators, including Ortho-McNeil and Merck. Additional 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 filings with the Securities and Exchange Commission. These forward-looking statements represent Arena's judgment as of the time of this release. Arena disclaims any intent or obligation to update these forward-looking statements, other than as may be required under applicable law.

Contacts:  Jack Lief                            Media:
                President and CEO                    Carin Canale
                                                     Atkins + Associates
                David Walsey                         (858) 527-3498
                Director, Corporate Communications

                Arena Pharmaceuticals, Inc.
                (858) 453-7200, ext. 1682

SOURCE Arena Pharmaceuticals, Inc.

Jack Lief, President and CEO, or David Walsey, Director, Corporate Communications,
both of Arena Pharmaceuticals, Inc., +1-858-453-7200, ext. 1682; or Carin Canale of
Atkins + Associates, +1-858-527-3498, for Arena Pharmaceuticals, Inc.
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