To: tuck who wrote (935 ) 2/25/2004 11:20:54 AM From: nigel bates Respond to of 1005 Arena finally DOES something ... TWICE ! Arena Pharmaceuticals Announces Achievement of $4 Million Success Milestone Under Merck Collaboration Wednesday February 25, 9:03 am ET SAN DIEGO, Feb. 25 /PRNewswire-FirstCall/ -- Arena Pharmaceuticals, Inc. (Nasdaq: ARNA - News) today announced the achievement of a $4 million milestone related to animal testing of small molecules that act upon selected G protein-coupled receptors (GPCRs), which may represent novel targets for cardiovascular disease. Arena and Merck have been collaborating since October 2002 on a group of GPCR targets discovered by Arena. Arena has performed high throughput small molecule screening on the target GPCRs, medicinal chemistry and subsequent in vitro and in vivo animal testing. The achieved preclinical milestone represents advancement in the potency and profile of identified small molecules in animal testing. Dr. Dominic P. Behan, Arena's Vice President, Research, stated, "It's been a pleasure working with the sophisticated scientific team at Merck. This milestone marks an important breakthrough in our collaboration." Dr. Ismail Kola, Merck Senior Vice President, added, "We are very pleased that our collaboration with Arena has been successful in advancing identified small molecules in animal testing." Arena is a biopharmaceutical company seeking to discover and develop drugs that act on an important class of drug targets called GPCRs. Arena initiated its first human studies on one of its internally discovered compounds for obesity in February 2004, which program is unrelated to the Merck collaboration. Arena uses its Constitutively Activated Receptor Technology, or CART(TM), Melanophore technology and other proprietary technologies to identify small molecules that may lead to new drugs in four major therapeutic areas: metabolic diseases, cardiovascular diseases, central nervous system disorders and inflammatory diseases. 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, technologies, preclinical and clinical programs, future achievements, and statements that are not historical facts, including statements about Arena's ability to identify and develop small molecules or which are preceded by the words "will," "expect" or similar words. 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. Important 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 SEC reports, including Arena's most recent quarterly report on Form 10-Q. These forward-looking statements represent Arena's judgment as of the date of this release. Arena disclaims any intent or obligation to update these forward-looking statements. Arena Pharmaceuticals® and Arena® are registered service marks of the company. CART(TM) is an unregistered service mark of the company. Arena's headquarters are at 6166 Nancy Ridge Drive, San Diego, CA 92121, and its telephone number is (858) 453-7200. On the Internet, please refer to Arena's website: www.arenapharm.com for further information.