Lexicon Completes Phase 1 Clinical Trials for Drug Candidate

THE WOODLANDS, Texas -- Lexicon Pharmaceuticals, Inc. (Nasdaq:LXRX), a biopharmaceutical company focused on discovering and developing breakthrough treatments for human disease, announced today that it has successfully completed a second Phase 1 clinical trial of LX1032, an orally-delivered small molecule drug candidate for managing gastrointestinal symptoms associated with carcinoid syndrome. Based on the results from this study, Lexicon is planning to initiate a Phase 2 study in patients with carcinoid syndrome. LX1032 will be Lexicon's third drug candidate to progress to Phase 2 clinical trials.

In the recently-completed Phase 1b multiple ascending-dose trial, LX1032 was well tolerated at all doses, including the maximum daily dose of 1,500 mg over the 14-day dosing period. Results from this trial demonstrated a potent reduction in both blood serotonin levels and urinary 5-HIAA, a marker of serotonin biosynthesis, at doses from 500 mg to the maximum dose of 1,500 mg, indicating that the target of LX1032 represents a new mechanism for regulating peripheral serotonin synthesis. The reduction in blood serotonin and urinary 5-HIAA levels observed in the multiple-dose study in normal healthy volunteers is consistent with the reduction in serotonin levels observed in preclinical animal models -- demonstrating conservation of the mechanism of action from mouse to man.

"The substantial reduction in serotonin observed in this study confirms our preclinical observations and suggests potent inhibition of peripheral serotonin production," said Philip M. Brown, M.D., J.D., senior V.P. of Clinical Development at Lexicon. "We are eager to test the compound in patients with carcinoid syndrome who suffer from significant gastrointestinal symptoms relating to the overproduction of serotonin."

In June 2008, Lexicon received Fast Track designation from the FDA for development of LX1032. Fast Track status facilitates the development of potential new drugs and expedites the review of new drugs intended to serve unmet medical needs in serious or life-threatening conditions.

Clinical development of LX1032 is being funded through a product development collaboration with Symphony Capital Partners, L.P. and its co-investors.

Video Presentation on LX1032
For additional information about the results of this study, please view the video presentation on Lexicon's Web site.

Source: Lexicon Pharmaceuticals Inc.