Lexicon Files for Investigational Drug Application

Lexicon Files for Investigational Drug Application for LX1032 as a Potential Treatment for Carcinoid Syndrome

The Woodlands, TX -- Lexicon Pharmaceuticals, Inc. (Nasdaq: LXRX) has submitted an investigational new drug (IND) application to the U.S. Food and Drug Administration (FDA) for LX1032, an oral drug candidate for managing gastrointestinal symptoms associated with carcinoid syndrome. The initial Phase 1 clinical trial of LX1032 is planned as a double-blind, randomized, placebo-controlled, ascending single-dose study in healthy volunteers. This study is designed to evaluate the safety, tolerability, and pharmacokinetics of LX1032. Lexicon expects to initiate clinical trials with LX1032 following FDA review.

"We believe LX1032 has the potential to be an important new therapy in an area of high unmet medical need," said Philip M. Brown, M.D., J.D., vice president of clinical development at Lexicon. "LX1032 may offer important benefits to patients with carcinoid syndrome, who have very limited treatment options."

Carcinoid syndrome is the result of metastatic carcinoid tumors that usually originate from enterochromaffin cells in the lining of the gastrointestinal tract. These tumors secrete large amounts of serotonin, which causes a variety of symptoms that often includes severe diarrhea and abdominal discomfort. Carcinoid tumors are a type of neuroendocrine tumor and, according to the American Cancer Society, about 11,000 to 12,000 neuroendocrine tumors and neuroendocrine cancers are diagnosed each year in the United States. About 10% of people with carcinoid tumors will develop carcinoid syndrome.

The target for LX1032 was identified through the Genome5000(TM) project, Lexicon's program to identify the function of 5,000 druggable genes in the human genome. LX1032 was developed at Lexicon as a potent inhibitor of tryptophan hydroxylase (TPH), a rate-limiting enzyme in the synthesis of serotonin. In preclinical studies, LX1032 was able to reduce peripheral serotonin in several different species without affecting serotonin levels in the brain. LX1032 is Lexicon's second compound to target TPH and, unlike LX1031, which acts locally within the gastrointestinal tract, was designed to act systemically.

LX1032 is being developed in a product development collaboration with Symphony Capital Partners, L.P. and its co-investors.

About Lexicon
Lexicon is a biopharmaceutical company focused on the discovery and development of 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, and autoimmune diseases. 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 diabetes and obesity, cardiovascular disease, psychiatric and neurological disorders, cancer, immune system disorders and ophthalmic disease. To advance the development and commercialization of its programs, Lexicon is working both independently and through collaborators including Bristol-Myers Squibb Company, Genentech, Inc. and N.V. Organon. For additional information about Lexicon and its programs, please visit the company's Web site.