|
Overview
A recent article in The New York Times  discusses the alliance between Colgate-Palmolive and Introgen Therapeutics, Inc., a Texas-based biotechnology company, to develop oral health products based on gene therapy in the treatment and prevention of oral cancers.
One of Introgen’s gene therapy products, INGN 234, transfers the p53 gene to cells through topical application as an oral rinse. The p53 gene is one of the most commonly mutated tumor suppressor genes in cancers. One of its primary roles in normal cells is regulating apoptosis , the process by which cells initiate their own death. Mutations of p53 cause a loss in regulation of apoptosis, preventing cells from dying. By transferring a functional copy of p53 to cells, INGN 234 can reinstate the regulation of cell death, which theoretically could treat or prevent cancer.
INGN 234 uses adenovirus, the common cold virus, to deliver the p53 gene to cells. The adenovirus is genetically altered in two important ways: the gene responsible for the common cold is removed, as are the genes responsible for viral replication. Because these genetic alterations theoretically make the virus safe, the adenovirus is commonly used for gene therapy. However, there have been reports of adverse events of gene therapy with adenovirus, including death of a clinical trial subject who received adenovirus by injection directly into the hepatic vein in 1999.
Introgen’s academic collaborators are currently conducting a combined phase 1 and phase 2 clinical trial of the INGN 234 oral rinse for preventing oral cancer in patients with leukoplakia. Introgen has a closely related gene therapy product, Advexin, that introduces p53 into cells through injection rather than topical application. Advexin is currently in a phase 3 clinical trial for head and neck squamous cell carcinomas, and has received “fast track" designation by the FDA.
Although gene therapy with the p53 gene delivered via an oral rinse holds much promise for prevention of oral cancers, further research on this application, including completion of the phase 1/2 trial prior to conducing a phase 3 trial, are needed. Concerns about safety of adenovirus remain. If proven safe and effective, this form of gene therapy may be useful for preventing oral cancer in at-risk patients. The ADA will continue to monitor the progress of INGN 234 and will disseminate information as it becomes available.
Return to Top
A–Z Topics: Oral Cancer
Return to Top
Science in the News is a service by the American Dental Association (ADA) to present current information about science topics in the news. The ADA is a professional association of dentists committed to the public's oral health, ethics, science and professional advancement; leading a unified profession through initiatives in advocacy, education, research and the development of standards. As a science-based organization, the ADA's evaluation of the scientific evidence may change as more information becomes available. Your thoughts would be greatly appreciated.
Document Posted November 2005
To view a PDF file, you need Adobe Reader. Click on the logo to download.
|
