Arena Pharmaceuticals, Inc.
Sep 26, 2007

Arena Pharmaceuticals Selected to Join New NASDAQ NeuroInsights Neurotech Index

SAN DIEGO, Sept. 26 /PRNewswire-FirstCall/ -- Arena Pharmaceuticals, Inc. (Nasdaq: ARNA) today announced that it has been selected to be one of the inaugural companies in the new NASDAQ® NeuroInsights® Neurotech Index.

The NASDAQ NeuroInsights Neurotech Index is an index designed to track the performance of selected neurotechnology companies which are listed on one of the three major U.S. stock exchanges. The NASDAQ NeuroInsights Neurotech Index includes companies engaged in researching, developing, manufacturing and marketing pharmaceuticals, biologics, medical devices and diagnostics for the brain and nervous system. In addition to meeting minimum market criteria, the 32 companies included in the index must be identified by NeuroInsights as significantly involved in the neurotechnology industry, which includes treatments and diagnostics for disorders like Alzheimer's, addiction, anxiety, depression, epilepsy, multiple sclerosis, obesity, pain, Parkinson's, schizophrenia, sensory disorders, sleep disorders, stroke, and traumatic brain injury.

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 product candidate, lorcaserin, is being investigated in a Phase 3 clinical trial program for the treatment of obesity. Arena's broad pipeline of novel compounds targeting G protein-coupled receptors, an important class of validated drug targets, includes compounds being evaluated independently and with its partners, Merck & Co., Inc. and Ortho-McNeil Pharmaceutical, 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, preclinical and internal and partnered 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, Arena's planned clinical trials may not proceed at the time Arena expects or at all, the results of preclinical studies or clinical trials may not be predictive of future results, Arena's ability to partner lorcaserin, APD125, APD791 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, 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.

SOURCE Arena Pharmaceuticals, Inc.

CONTACT: Jack Lief, President and CEO, or David Walsey, Director, Corporate Communications, both of Arena Pharmaceuticals, Inc., +1-858-453- 7200, ext. 1682; or Mary Claire Duch of WeissComm Partners, +1-212-301-7228, for Arena Pharmaceuticals, Inc.
Web site: http://www.arenapharm.com