Lexicon Genetics has Initiated More Than 40 Drug Discovery Programs from its Genome5000(TM) Program

In its Genome5000 program, Lexicon is analyzing 5,000 genes using its proprietary gene knockout technologies and its extensive physiological and behavioral analyses to discover novel drug targets from the human genome. Based on this physiological and behavioral information, Lexicon selects targets for its drug discovery programs that, when knocked out, exhibit favorable therapeutic profiles for the development of drugs. To date, Lexicon has completed the analysis of more than 1,400 genes. Lexicon expects to fully analyze an additional 900 genes in 2004.

Lexicon’s Genome5000 Program is focused on the discovery of the functions in mammalian physiology of protein families selected based on their desirable characteristics for pharmaceutical development, such as G-protein coupled receptors (GPCRs), nuclear hormone receptors, ion channels, transporters, kinases, proteases, key enzymes and secreted proteins.

“Our analysis of the in vivo function of more than 1,400 genes has given us excellent information on which human genes are the best targets for drug development,” said Arthur T. Sands, M.D., Ph.D., Lexicon’s president and chief executive officer. “We believe that each of our more than 40 drug discovery programs represents an important biological finding and a compelling pharmaceutical opportunity to address a major unmet medical need.”

Lexicon’s most advanced drug development programs include LG617 for Alzheimer’s disease and cognition, LG653 for obesity and diabetes, LG314 for obesity and diabetes and LG152 for solid tumors.

About Lexicon Genetics

Lexicon Genetics is a biopharmaceutical company focused on the discovery of breakthrough treatments for human disease. Lexicon is using gene knockout technology to systematically discover in living mammals, or in vivo, the physiological functions and pharmaceutical utility of genes. The Company’s gene function discoveries fuel therapeutic discovery programs in diabetes, obesity, cardiovascular disease, psychiatric and neurological disorders, cancer, immune system disorders and ophthalmic disease. Lexicon has established drug discovery alliances and functional genomics collaborations with leading pharmaceutical and biotechnology companies, research institutes and academic institutions throughout the world to commercialize its technology and turn its discoveries into drugs. Additional information about the Company is available through Lexicon’s corporate website, www.lexicon-genetics.com.

Safe Harbor Statement

This press release contains “forward-looking statements,” including statements about 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. These 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 develop drug candidates from its discoveries, achieve its operational objectives, obtain patent protection for its discoveries and establish strategic alliances, 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 “Business – Risk Factors” in Lexicon’s annual report on Form 10‑K for the year ended December 31, 2002, 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.

Message posted by: Frank S. Zollmann