Researchers Urge Continued Careful Human Trials of Gene Therapy for Heart Disease
For the first time, Isner released the results of his 30-patient gene therapy trial. After 12 weeks, 70% of the patients had a significant decrease in angina symptoms, and their ability to exercise increased. "We believe that the data to date continue to show that VEGF-2 is a worthy candidate for continued development," says Isner, although he admits that it's too early to determine if new vessel growth -- or angiogenesis -- has actually taken place.
And, in another presentation, researchers discussed data that another growth factor -- fibroblast growth factor (rFGF-2) -- is showing promise in treating patients with advanced heart disease. This protein works on a number of different cells in the body, not just those associated with vessel growth. In a comparison against placebo in 337 patients with severe angina, those receiving the therapy had significant improvements in symptoms and exercise tolerance after 90 days of therapy compared to those taking the placebo. Researcher Michael Simons, of Beth-Israel Deaconess Medical Center in Boston, says that there was a significant difference in improvement between the two groups.
Timothy D. Henry, MD, director of interventional cardiology at Hennepin County Medical Center and an associate professor of medicine at the University of Minnesota in Minneapolis, says that despite the recent controversy over gene therapy, studies employing this technique, as well as those administering growth factors, have promising results in early trials. "It is important to remember that ... [the ability to grow new blood vessels] is a field [of medicine that is] in its infancy ... it's really brand new," he says. "There are a lot of questions still that can only be answered with further study."