Arena Pharmaceuticals to Host Business and Financial Update Conference Call and Webcast on Tuesday, November 10, 2009

November 4, 2009

SAN DIEGO, Nov. 4, 2009 /PRNewswire-FirstCall/ -- Arena Pharmaceuticals, Inc. (Nasdaq: ARNA) today announced it will report third quarter 2009 financial results after the NASDAQ Global Market closes on Monday, November 9, 2009. The next morning, November 10, 2009, Jack Lief, Arena's President and Chief Executive Officer, and Robert E. Hoffman, Arena's Vice President, Finance and Chief Financial Officer, will host a conference call at 8:30 a.m. Eastern Time (5:30 a.m. Pacific Time) to discuss the financial results for the third quarter 2009 and to provide a business and financial update.

The conference call may be accessed by dialing 888.452.4024 for domestic callers and 719.325.2385 for international callers. Please specify to the operator that you would like to join the "Arena Pharmaceuticals' Third Quarter 2009 Financial Results Call." The conference call will be webcast live under the investor relations section of Arena's website at www.arenapharm.com, and will be archived there for 30 days following the call. Please connect to Arena's website several minutes prior to the start of the broadcast to ensure adequate time for any software download that may be necessary.

About Arena Pharmaceuticals

Arena is a clinical-stage biopharmaceutical company focused on discovering, developing and commercializing oral drugs in four major therapeutic areas: cardiovascular, central nervous system, inflammatory and metabolic diseases. Arena's most advanced drug candidate, lorcaserin, is being investigated in a Phase 3 clinical trial program for weight management. Arena's broad pipeline of novel compounds target G protein-coupled receptors, an important class of validated drug targets, and includes compounds being evaluated independently and with partners, including Merck & Co., Inc., and Ortho-McNeil-Janssen Pharmaceuticals, Inc.

Arena Pharmaceuticals® and Arena® are registered service marks of the company. "APD" is an abbreviation for Arena Pharmaceuticals Development.

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 Arena's strategy, internal and partnered 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 timing, success and cost of Arena's lorcaserin program and other of its research and development programs; regulatory authorities may not find data from Arena's clinical trials and studies sufficient for regulatory approval; the timing and ability of Arena to receive regulatory approval for its drug candidates; results of clinical trials or preclinical studies may not be predictive of future results; clinical trials and studies may not proceed at the time or in the manner Arena expects or at all; Arena's ability to partner or commercialize lorcaserin or other of its compounds or programs; Arena's ability to obtain additional funds; Arena's ability to obtain and defend its patents; and the timing and receipt of payments and fees, if any, from Arena's collaborators. 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.

    Contact: Arena Pharmaceuticals, Inc.     Media Contact: Russo Partners

    Jack Lief                                David Schull, President
    President and CEO                        david.schull@russopartnersllc.com
                                             858.717.2310
    Cindy McGee
    Manager, IR and Corporate Communications
    858.453.7200, ext. 1479                  Anthony J. Russo, Ph.D., CEO
                                             tony.russo@russopartnersllc.com
                                             212.845.4251

SOURCE Arena Pharmaceuticals, Inc.