Novel treatment promotes blood vessel growth in heart muscle, researchers say
TUESDAY, Sept. 4 (HealthDay News) -- A trial testing a genetically engineered treatment in women who have angina, the piercing chest pain that can bedevil the millions of Americans with heart disease, has been given fast-track status by the U.S. Food and Drug Administration.
The study will enroll about 300 women at 50 medical centers in the United States, said Dr. Randall Moreadith, chief medical officer of Cardium Therapeutics Inc., the San Diego company that developed the therapy. They will receive infusions of a harmless virus engineered to carry a gene that promotes development of new blood vessels. The pain of angina is caused by insufficient blood flow to the heart muscle.
The fact that the FDA is pushing a trial of the therapy indicates the urgent need for a new angina treatment, said Christopher J. Reinhard, chief executive office of Cardium. "These are patients who are getting maximum drug medication, have had bypass surgery and continue to have recurrent angina. They have nowhere else to turn."
Two earlier studies that included both men and women found no overall improvement with the treatment, according to a report in the Sept. 11 issue of the Journal of the American College of Cardiology.
"But when we broke the data down by gender, there was a striking difference in women on exercise treadmill duration," Moreadith said. "Then we saw that every one of the clinical endpoints in women lined up. That was a surprise finding to us."
The treatment uses two technologies developed at different academic institutions -- the FGF-4 gene, discovered at New York University, and delivery by infusion through a catheter placed in a blood vessel, developed at the University of California.
"We have been in a program involving four multi-center studies, with the same delivery mechanism and the same product, evaluating it in the classic way," Moreadith said.
The two earlier clinical trials found that men given a placebo were more likely to report favorable results. Both trials, which included a total of 532 people with angina, were halted when interim analysis of the data showed no overall significant improvement for the entire group. Analysis of subsets of people in the trials led to the current study.
It's not possible to say when results of the current trial will be available, Reinhard said.
The idea of promoting the growth of new blood vessels in the heart "opens a new frontier in the cardiac arena," Reinhard added. Existing treatments for angina are aimed at easing the symptoms of the condition by widening blood vessels, either temporarily with drugs such as nitroglycerin or permanently with procedures such as bypass surgery.
Gene therapy to improve the heart's oxygen supply by inducing development of new blood vessels "deals with the underlying problem," Reinhard explained.
The idea that this therapy could work differently in women makes sense because the physical nature of the condition causing angina is often different in the two sexes, explained Dr. Suzanne Steinbaum, director of women and heart disease at Lenox Hill Hospital in New York City.
In women, diminished blood flow to the heart often is due to general narrowing of many of the arteries feeding the heart, while in men the problem tends to be concentrated in one area, Steinbaum said.
"Women have more diffuse disease, so if you provide more conduits you will have more blood flow and less angina," she said. "With men, the problem is more discrete, so providing more conduits might not relieve symptoms."
"There definitely is something to this that makes sense," Steinbaum said.
In related news, Swedish researchers at the European Society of Cardiology meeting in Vienna suggested on Monday that women with heart disease might need to be treated differently than men.
The Associated Press reported that a small study of 184 women conducted by Dr. Eva Swahn of the department of cardiology at University Hospital in Linkoping, Sweden, found that women who had major heart operations like a coronary bypass were more likely than men to die.
Although experts said no conclusions could be drawn from the finding, they agreed that the idea that women might need different heart disease treatment than men should be studied further, according to the AP.
The full story of angina, its causes, symptoms and treatment, is provided by the U.S. National Library of Medicine.
SOURCES: Randall Moreadith, M.D., Ph.D., chief medical officer, and Christopher J. Reinhard, chief executive officer, Cardium Therapeutics Inc., San Diego; Suzanne Steinbaum, M.D., director, women and heart disease, Lenox Hill Hospital, New York City; Sept. 11, 2007, Journal of the American College of Cardiology
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