WEDNESDAY, April 7, 2004 (HealthDayNews) -- A new, as yet unmarketed, drug can successfully raise blood levels of HDL cholesterol, the "good" kind that carries away fats that can block arteries.
That what a new study finds. And now it's on to the real question: Will higher levels of HDL (high-density lipoprotein) cholesterol actually decrease the risk of heart attack, stroke, and other cardiovascular conditions?
That question can be answered only by trials that are just beginning, according to Margaret E. Brousseau, assistant professor of medicine at Tufts University School of Medicine and the lead author of a report on the effects of the drug, torcetrapib. The study appears in the April 8 issue of the New England Journal of Medicine.
"We did this trial to get an idea of the effect of the drug on protein metabolism," Brousseau said. "It did quite well, better than any of the currently available agents, and also in terms of other drugs in the process of development."
Phase III trials, the large-scale, long-term studies needed to prove the protective value of torcetrapib to the satisfaction of the U.S. Food and Drug Administration, have just begun, said Kate Robins, a spokeswoman for Pfizer Inc., the company that is developing the drug. Such trials can last two or three years, or even longer.
When and if torcetrapib gets FDA approval, Pfizer plans to market it only in combination with another of its products, Lipitor, the best-selling statin drug that lowers blood levels of artery-clogging LDL (low-density lipoprotein) cholesterol, Robins said.
That is quite appropriate, said Dr. H. Bryan Brewer, Jr., chief of the molecular disease branch of the National Heart, Lung and Blood Institute, who wrote a perspective piece accompanying the journal report.
"Obviously, this is not a drug to replace the statins," Brewer said. "We need to reduce LDL levels. This should be used in combination with a statin."
Both epidemiological studies in humans and laboratory studies in animals have indicated that raising HDL levels reduces the risk of cardiovascular disease, Brewer said. Those studies have created "a great deal of interest in an approach to raise HDL levels," he said.
The study done by Brousseau and her colleagues was partially funded and conducted by Pfizer, and included only 19 participants. Some got torcetrapib alone, others got that drug and a statin. HDL cholesterol levels went up by 61 percent in those who got a daily dose of 120 milligrams of torcetrapib alone for four weeks and by 46 percent in those who also got the statin.
Doubling the torcetrapib dose to 240 milligrams daily more than doubled HDL cholesterol levels, the researchers reported. LDL cholesterol levels dropped by 17 percent in people who got either the higher or lower doses of torcetrapib.
"The next piece of the puzzle is to see whether higher HDL levels act to protect against cardiovascular disease," Brewer said. "To know definitely, we need to do the studies that now are under way. It would be very encouraging if this would be the case."
More information
A primer on the good and bad effects of the two kinds of cholesterol can be found at the American Heart Association or the National Heart, Lung and Blood Institute.
