Lexicon to Present Phase 2 Clinical Data for IBS Drug Candidate at Digestive Disease Week

THE WOODLANDS, Texas,April 27/PRNewswire-FirstCall/ --Lexicon Pharmaceuticals, Inc.(Nasdaq:LXRX), a biopharmaceutical company focused on discovering and developing breakthrough treatments for human disease, announced today that the company will be giving poster and oral presentations on results from its Phase 2 clinical study withLX1031in patients with non-constipating irritable bowel syndrome (IBS) at Digestive Disease Week (DDW) 2010 inNew Orleans, Louisiana. Results from the study, in which LX1031 produced improvements in IBS symptoms, will be presented during the poster session onSunday, May 2, 2010from12 p.m. to 2 p.m. Central Timeand the oral presentation onWednesday, May 5, 2010at9:30 a.m. CT(session start time is8:30 a.m. CT).

DDW is the world's largest gathering of physicians and researchers in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery. Every year it attracts approximately 16,000 physicians, researchers and academics from around the world.

Clinical development of LX1031 is being funded through a product development collaboration with Symphony Capital Partners, L.P. and its co-investors.

For more information on this program, and to access the presentations (available afterMay 5, 2010), please visitwww.lexpharma.com.

Lexicon is a biopharmaceutical company focused on discovering and developing breakthrough treatments for human disease. Lexicon currently has four drug candidates in mid-stage development for diabetes, irritable bowel syndrome, carcinoid syndrome and rheumatoid arthritis, all of which were discovered by Lexicon's research team. Lexicon has used its proprietary gene knockout technology to identify more than 100 promising drug targets. Lexicon has focused drug discovery efforts on these biologically-validated targets to create its extensive pipeline of clinical and preclinical programs. For additional information about Lexicon and its programs, please visitwww.lexpharma.com.

This press release contains "forward-looking statements,"including statements relating to Lexicon's clinical development of LX1031 and the potential therapeutic and commercial potential of LX1031.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 LX1031 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 endedDecember 31, 2009, 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.