Lexicon patents gene trapping technology.

Lexicon Genetics, Inc. (The Woodlands, TX) announced that it has been issued United States Patent 6,436,707 (the "707 patent ") entitled "Vectors for Gene Mutagenesis and Gene Discovery." The newly-issued patent extends the scope of Lexicon's broad patent estate in the field of gene trapping, now covered by a total of six issued United States patents. The companyalso announced the recent issuance of two United States patents covering the full-length sequences of potential drug targets discovered through its gene discovery programs. These two patents mark the beginning of a continuing pipeline of expected patent issuances from Lexicon's portfolio of patent applications covering more than 300 full-length human gene sequences.

The 707 patent covers Lexicon's OmniBank library of more than 200,000 gene knockout embryonic stem cell clones, each of which is identified by DNA sequence from the trapped gene. Knockout mice from OmniBank have been the source of nine of the Company's 14 drug discovery programs to date, the remainder having been derived from Lexicon's complementary gene targeting technologies. OmniBank is expected to represent about one-half of the gene knockouts in Lexicon's Genome5000 program, which is designed to systematically discover the physiological functions and pharmaceutical utility of 5,000 genes over five years. Lexicon estimates that OmniBank contains gene knockout clones for more than one-half of all genes in the mammalian genome.

"The technology covered by this and our other gene trapping patents has enabled us to build an unprecedented resource for drug target discovery," said Arthur T. Sands, M.D., Ph.D., President and Chief Executive Officer of Lexicon. "Our OmniBank library of gene knockout clones, encompassing more than one-half of the mammalian genome, gives us the ability to move from the sequence of a gene to in vivo analysis of its function in mammalian physiology in significantly less time, with more throughput and at a fraction of the cost of other approaches. We believe that the combination of OmniBank and our industrialized gene targeting capabilities provide Lexicon with unparalleled strategic advantages in the discovery of the physiological functions of genes and, ultimately, of breakthrough therapeutics."

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 the physiological functions and medical uses of genes. The company's gene function discoveries fuel therapeutic discovery programs in cardiovascular disease, diabetes, obesity, immune disorders, neurological disease and cancer. 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 further develop its discoveries.

Lexicon Genetics, Inc. [phone] www.lexicon-genetics.com