• 11/7/2005
  • New York, NY
  • Andrew Pollack
  • New York Times (www.nytimes.com)

Brush your teeth and rinse with gene therapy. That could be the future of oral health care as envisioned by Colgate-Palmolive and Introgen Therapeutics, an Austin, Tex., biotechnology company.

The companies announced an alliance Friday to incorporate gene therapy – an exotic, experimental and so far largely unsuccessful form of medicine – into mouthwashes, gels and similar products to treat and prevent oral cancers.

Gene therapy involves putting genes into cells in the body, often to replace native genes that are malfunctioning. The technique has rarely worked in the 15 years it has been tried, largely because of the difficulty of getting enough functioning genes into cells.

Introgen’s method puts so-called tumor suppressor genes into cancerous cells to stop the growth of tumors. The company’s most advanced drug, which is in late-stage clinical trials, is a treatment for head and neck cancer that it hopes will be the first gene therapy approved in the United States. In that treatment, viruses containing the desired gene are injected directly into tumors.

Working with Colgate, Introgen will try to put the tumor suppressor genes into an oral product to treat leukoplakia, a precancerous condition characterized by lesions on the cheeks, gums or tongue. In some cases the lesions turn cancerous, usually after many years. Dr. Robert E. Sobol, Introgen’s senior vice president for medical and scientific affairs, said an initial product would probably be a prescription drug that would require approval by the Food and Drug Administration. But he said he hoped eventually the product could be sold over the counter.

The company is already in early stages of human testing of a mouthwash containing a tumor-suppressor gene. The mouth is “just such an easy place to apply these therapies,” said Dr. Sobol, explaining that it was easy to reach and see the damaged cells. Nevertheless, getting enough genes into cells in the mouth could still be difficult.

Introgen puts its gene into a disarmed cold virus, called an adenovirus, which infects cells and carries in the gene. While Dr. Sobol said the technique was safe, an adenovirus was used in a gene therapy experiment that killed a teenager at the University of Pennsylvania in 1999. Dr. Sobol said that if Introgen wanted to develop a product that would be used widely by people who do not yet have cancer, it might have to use a gene therapy approach that did not involve a virus.

Colgate, which is based in New York, said in a statement that the alliance would give it “insight into a very exciting technology with potential application to oral health.”

The company said the alliance was not a move into the pharmaceutical business but rather one of many research efforts it has involving oral health. Known mostly for consumer products, Colgate sells products used by or prescribed by dentists, including the PerioGard antibiotic rinse to fight the gum disease gingivitis.