By Erin Saylor
Daily Staff Reporter
New research shows that a treatment aimed at helping patients with blocked leg arteries fails to improve their conditions. But a University cardiologist says that similar treatments currently being tested may one day succeed.
Run by the University Cardiovascular Center, phase II of the RAVE trial tested the efficacy of an injection of a gene into the leg to encourage the growth of new blood vessels. The injections were given to 105 patients suffering from peripheral arterial disease.
Partly the result of high cholesterol and high blood pressure, PAD is the hardening and clogging of the blood vessels in the leg – the same condition that can cause heart attacks. The disease affects two million Americans.
While the study showed the injection had no side effects, it also revealed that there was no significant improvement in the patients compared to that provided by the placebo, or dummy treatment.
The trial is the largest such trial on PAD ever conducted.
“We measured the walking distances of the patients on treadmills before they were given the treatment, and then again after 12 weeks of receiving the injections,” said cardiologist Sanjay Rajagopalan, the study’s principal investigator.
Results showed that 12 weeks after receiving a one-time set of 20 injections of the gene for vascular endothelial growth factor, patients who received both the high and low injections could walk an average of 1.6 and 1.5 minutes longer, in comparison to placebo patients who could walk 1.7 minutes longer.
“Unfortunately, the results were negative, showing that this exact type of approach is ineffectual,” Rajagopalan said.
But, he stressed that though this particular study was unsuccessful, the entire area of gene transfer is still in its infancy and shows signs of being a very useful treatment in the future.
“Gene transfer is a very attractive alternative to treatments like insulin, which has to be taken every day,” Rajagopalan said. “It triggers growth that would continue to work for a while, which is much more efficient.”
The research was conducted in 30 centers across the United States from 1999 to 2002 and examined PAD patients ranging from 40 to 80 years old.
“The quality of life for these people is miserable,” Rajagopalan said. “With very severe cramping in the lower legs, most of our patients were unable to walk a half a block.”
He said that it is extremely important to find a way to treat people with PAD. Only one treatment for PAD has been approved, which came out five years ago.
“This treatment is not very effective and has side effects,” Rajagopalan said. Patients must take the treatment throughout their lives, he added.
He said studies to test the benefits of alternate growth factors and master switch genes are in clinical trials right now, the results of which he said he hopes will be available by the end of the year.
“In the future, we are hoping to use gene transfer to provide long-lasting relief of symptoms,” Rajagopalan said.