By Frances Bishopp

Vyrex Corp. and The Immune Response Corp. have signed a letter of intent for the development and discovery of proteins and small molecules involved in nerve growth and repair.

Vyrex, of La Jolla, Calif., and Immune Response, of Carlsbad, Calif., will combine Vyrex's proprietary functional genomics technology, CD-Tagging, with Immune Response's extensive research capabilities and expertise in molecular biology and gene therapy, said Steven Kemper, chief financial officer at Vyrex.

The financial details of the collaboration have not been disclosed. Vyrex and Immune Response will own discovered products jointly, Kemper said.

"Dennis Carlo, president and CEO of Immune Response, and I have a very strong interest in development of drugs for the treatment of central nervous system and peripheral nervous system trauma," Sheldon Hendler, CEO and chairman of Vyrex, told BioWorld Today. "This project will focus on nervous system injury generally, specifically, head and spinal cord injury," Hendler said.

Hendler's interest and involvement in the project is particularly poignant in that he lost his 17-year-old son several years ago, when the young man sustained a head injury in an automobile accident.

A philosopher friend of Hendler's told him once that all great scientific discoveries really come from personal issues, rather than from solving intellectual crossword puzzles, Hendler recalled. "I believe that's entirely true," he said. "The most important discoveries are the most important things we can do, if they are grounded to something personal to us."

Invented by Jonathan Jarvik, vice president of biology at Vyrex, CD-Tagging is a functional technology that incorporates heredity tags into genes, transcripts and proteins via recombinatorial events at the DNA level. CD-Tagging can be used to analyze known genes and gene products and to identify and characterize new ones.

The technology consists essentially of inserting a short stretch of DNA, the CD cassette, into an intron, a non-translating sequence, of a target gene. This open reading frame is flanked by splice acceptor and donor sites. When the intron is splice-excised during assembly of the gene's exons prior to translation, that synthetic nucleotide sequence becomes a new "guest exon," carried along into the messenger RNA and subsequently expressed as a specific peptide sequence in the final protein.

A major advisor for the gene discovery project, Hendler said, is Nobel Laureate Kary Mullis, who is on Vyrex's advisory board.

Vyrex raised $6.5 million in an initial public offering in April 1996. The company has four research programs under way with the most advanced aimed at combating oxidative damage triggered by the overproduction in the body of oxygen-free radicals.

The other three programs target discovery of genes and their proteins; the use of cyclodextrins, a water-soluble starch, to deliver oil-like drugs that don't mix with water; and therapeutics that induce apoptosis in cancer cells.

Formed last year, a fifth program or division, Nutrex, will focus on developing products for the nutraceutical market. The company will focus on the role vitamins, minerals and other nutrients play in the disease process and aging.

Vyrex's lead product, Panavir, currently in clinical trials, is designed to prevent HIV activation from the virus' latent state.

Other collaborations for Vyrex include agreements with SeqWright, a gene sequencing company in Houston, to use Vyrex's CD-Tagging technology to construct mouse and human functional genomic libraries; Pollufil Trading S.A., of Geneva, Switzerland, for development of an antioxidant cigarette filter; and American Qualex International Inc., of San Clemente, Calif., for sale of an epitope-tagging kit. Epitopes are parts of antigens that trigger formation of antibodies. *