THE WOODLANDS, Texas, April 15, 2008 (PRIME NEWSWIRE) -- Lexicon Pharmaceuticals, Inc. (Nasdaq:LXRX), a leader in genomics-based drug discovery, presented data today describing the target of LX6171 and initial Phase 1 clinical results at the American Academy of Neurology in Chicago. LX6171 is an internally-developed compound under evaluation by the company as a potential treatment for cognitive disorders. LX6171, currently in Phase 2 clinical testing, is one of four programs in human clinical trials as part of Lexicon's 10TO10 program.

LX6171 is an orally-delivered, small molecule inhibitor of SLC6A7, a high-affinity L-proline transporter found in the brain. SLC6A7 is a member of the gamma-aminobutyric acid (GABA) neurotransmitter transporter family, and is expressed in regions of the brain that are known to be involved in learning and memory. In preclinical studies, mice treated with LX6171 displayed improved performance in tests of learning and memory, corroborating observations in knockout mice lacking SLC6A7.

"Until we identified and analyzed SLC6A7 in our Genome5000(tm) program, relatively little was known about this transporter and its role in behavior," said Dr. Brian Zambrowicz, Lexicon's chief scientific officer. "Our results indicate that inhibiting this target may delineate a novel approach to the treatment of cognitive disorders."

"Initial human studies with both young and elderly volunteers have shown that the compound achieves good systemic exposure and is well tolerated at the doses studied," said Philip M. Brown, M.D., J.D., senior vice president of clinical development at Lexicon. "LX6171 may have potential in a broad range of applications involving cognitive disorders, including Alzheimer's disease, attention disorders, and developmental disorders."

Clinical Results

In Phase 1 clinical trials, LX6171 was generally well tolerated at all dose levels and showed good systemic exposure with no significant adverse events or cognitive impairment observed. Preliminary data on attention parameters were encouraging and suggest the appropriateness of proceeding with further studies to determine if LX6171 could have a potential effect on cognitive or attention disorders.

LX6171 is currently under evaluation in a Phase 2 clinical trial to evaluate the safety, tolerability and cognitive effects of LX6171 in approximately 100 elderly subjects with age-associated memory impairment (AAMI). The placebo-controlled trial will include a low dose group receiving 120 mg of the drug candidate once per day, and a higher dose group receiving 240 mg once per day. Both groups will receive the drug candidate for 28 days and will be evaluated regularly for effects on several dimensions of learning and memory. LX6171 is being developed in a product development collaboration with Symphony Capital Partners, L.P. and its co-investors.

About Lexicon

Lexicon is a leader in genomics-based drug discovery. Through its proprietary gene knockout technology, the company is dedicated to discovering and developing breakthrough treatments for human disease. Lexicon currently has development programs underway for such areas of major unmet medical need as irritable bowel syndrome, cognitive disorders, autoimmune diseases, and carcinoid syndrome. The company has used its proprietary gene knockout technology to discover more than 100 promising drug targets and create an extensive pipeline of clinical and preclinical programs in the therapeutic areas of cardiology, gastroenterology, immunology and oncology, metabolism, neurology and ophthalmology. To focus its commitment, Lexicon initiated its 10TO10 program to advance 10 new drug candidates into human clinical trials by the end of 2010. To advance the development and commercialization of its programs, Lexicon is working both independently and through collaborators including Bristol-Myers Squibb Co., Genentech, Inc. and N.V. Organon. For additional information about Lexicon and its programs, please visit www.lexpharma.com.

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Safe Harbor Statement

This press release contains "forward-looking statements," including statements relating to Lexicon's clinical development of LX6171 and the potential therapeutic and commercial potential of LX6171. This press release also contains forward-looking statements relating to Lexicon's growth and future operating results, discovery and development of products, strategic alliances and intellectual property, as well as other matters that are not historical facts or information. All forward-looking statements are based on management's current assumptions and expectations and involve risks, uncertainties and other important factors, specifically including those relating to Lexicon's ability to successfully conduct clinical development of LX6171 and preclinical and clinical development of its other potential drug candidates, advance additional candidates into preclinical and clinical development, obtain necessary regulatory approvals, achieve its operational objectives, obtain patent protection for its discoveries and establish strategic alliances, as well as additional factors relating to manufacturing, intellectual property rights, and the therapeutic or commercial value of its drug candidates, that may cause Lexicon's actual results to be materially different from any future results expressed or implied by such forward-looking statements. Information identifying such important factors is contained under "Factors Affecting Forward-Looking Statements" and "Risk Factors" in Lexicon's annual report on Form 10-K for the year ended December 31, 2007, as filed with the Securities and Exchange Commission. Lexicon undertakes no obligation to update or revise any such forward-looking statements, whether as a result of new information, future events or otherwise.

Lexicon Pharmaceuticals, Inc.
Bobbie Faulkner, Manager, Investor and Public Relations
281-863-3503