Gene Therapy: Promise Runs High despite Recent Setback

Article excerpt

After a string of successes, gene therapy suffered a setback in September when a patient died at the University of Pennsylvania after receiving a dose of corrective genes encased in adenovirus, a weakened cold virus. The death was the first directly attributable to gene therapy, and investigations are under way to define the cause and hopefully develope better guidelines to prevent such occurrences.

What is gene therapy? In certain patients with genetic diseases, the defective gene has been identified, and the disease is the result of the failure of the gene to function properly. The classic and still best-known example of these is sickle cell anemia, which is caused by a defect in the gene encoding hemoglobin, the protein that carries oxygen in the blood. Once scientists identified the defective gene, it was only a matter of time before they would attempt to reintroduce the "normal" gene into the system. W. French Anderson, a Tulsa native, is one of the pioneers in this field (Anderson was inducted into the Oklahoma Hall of Fame two years ago).

The "vehicle" by which gene therapy is administered is usually a simple virus. The typical method usually involves introducing the virus into "stem cells," the cells that give rise to the blood cells. As more experience was gained through the years, gene therapy was applied to a wider variety to medical conditions, including cystic fibrosis and hemophilia.

Almost all those in biomedical science and biotechnology see gene therapy as the wave of the future, not only for the treatment of genetic diseases but as a way of treating a variety of diseases in a "single dose." That is to say, for example, if someone needed insulin every day, it is conceivable that it could be delivered by gene therapy and regulated just as the normal insulin level in the body is maintained, freeing the patient from having to take an insulin shot once or twice a day. Or, for a patient needing medication to reduce blood pressure, a system could be devised through which a gene encoding a blood pressure-reducing substance could be introduced and regulated by the patient's own blood pressure. …