Valentis issued third patent for GeneSwitch technology.

Valentis, Inc. (Burlingame, CA; 650-697-1900) announced that the United States Patent and Trademark Office has issued a third patent covering the company's GeneSwitch gene regulation technology. United States patent 5,935,934 titled, "Mutated Steroid Hormone Receptors, Methods for Their Use and Molecular Switch for Gene Therapy," issued August 10, 1999.

The GeneSwitch technology provides precise control over the level and duration of gene expression when introduced via gene therapy. Using the GeneSwitch, therapeutic genes may be expressed by administration of an orally bioavailable drug in a dose-dependent manner. Levels of a therapeutic protein can be controlled as needed by administration of the regulating drug in pill form.

Applications of the GeneSwitch technology include viral and plasmid-based gene therapy, as well as functional genomic studies using transgenic animals. Valentis' patents on the GeneSwitch technology, which also include previously issued United States Patent 5,364,791 and 5,874,534, cover gene regulation using steroid hormone receptors in any gene delivery system and specifically include the regulation of therapeutic genes in the body.

"The strong proprietary position and solid preclinical performance characteristics of the GeneSwitch make it a valuable part of the technology Valentis uses to develop gene therapy products," stated Benjamin F. McGraw, chairman, president and chief executive officer of Valentis. "Certain gene therapies require control over the level and duration of expression of the therapeutic proteins they produce. GeneSwitch gives us the capability to turn the activity of the gene on or off as needed, enhancing the control of gene therapy products."

The functionality of the GeneSwitch technology to regulate long-term gene expression using a plasmid-based system was published in the June 10, 1999 issue of the journal, Human Gene Therapy by Valentis scientists. The paper showed induction of high levels of gene expression in the muscle and secretion of protein in bloodstream after administration of very low doses of an antiprogestin drug. Repetitive regulation of gene expression was achieved for several weeks after a single dose of the GeneSwitch plasmid.

The patent was issued to Baylor College of Medicine (Houston, TX), to which Valentis has an exclusive license. The GeneSwitch technology was originally developed in the laboratory of Dr. Bert W. O'Malley, MD, chairman of the department of cell biology at Baylor, and a member the Valentis board of directors. The full text of the patent can be found on the Internet at: www.uspto.gov.

Valentis, formed in March 1999 by the merger of GeneMedicine, Inc. and Megabios Corporation, is focused on the development of products incorporating its proprietary biologics delivery systems. The company uses its expertise in gene delivery and expression to create gene medicines that are intended to provide a new approach to the treatment of diseases with high unmet need or where current therapies are inadequate. The company's initial focus has been on the development of gene medicines for treating certain cancers, cardiovascular diseases, neuromuscular disorders, and pulmonary diseases, as well as the development of genetic vaccines for the treatment or prevention of infectious diseases. Gene medicines deliver instructions to targeted cells in the body to produce therapeutic proteins.

The company has established corporate partnerships with Hoffman-La Roche (Switzerland), Eli Lilly and Company (Indianapolis, IN; 317-261-2000), Glaxo Wellcome plc (London, United Kingdom) and a manufacturing partnership with DSM Biologics and Qiagen NV.