Updated from Nov. 9

Research sponsored by

Pfizer

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shows patients receiving the company's blood pressure drug Norvasc had fewer cardiac problems than patients who received standard care.

The study released on Tuesday said Norvasc patients had 31% fewer "major cardiovascular events," which include heart attacks, strokes and hospitalizations for heart-related problems or death. The study examined patients with coronary artery disease -- people whose arteries were clogged to cholesterol-rich fatty deposits called plaque. Standard care includes aspirin and cholesterol-fighting drugs.

The research was published in the latest edition of the

Journal of the American Medical Association

.

Norvasc's ability to reduce blood pressure and chest pains associated with heart disease "may contribute to the overall reduction in cardiovascular events in patients with coronary artery disease," said Dr. Peter Libby, a Harvard Medical School professor who served on the steering committee for the study nicknamed Camelot. Libby has received research funds from Pfizer and is a Pfizer consultant. Several of the article's authors are Pfizer employees.

Libby noted that a subset of the study showed that Norvasc "may also slow plaque progression" in arteries, "which may further contribute to improved clinical outcomes."

The Camelot study looked at Norvasc, which belongs to the calcium channel class of blood pressure drugs, as well as enalapril, a now-generic blood pressure drug that also is marketed as Vasotec by

Merck

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. Merck no longer markets the drug in the U.S. Vasotec belongs to the class of drugs called ACE inhibitors.

The 1,997 patients in the clinical trials received Norvasc, enalapril or a placebo. The goal was to determine how well the medications reduced "major cardiovascular events" in people with coronary artery disease. The study involved 100 sites in the U.S., Canada and Europe.

The research found that Norvasc patients experienced 42% fewer hospitalizations for chest pain and 27% fewer procedures or surgeries to restore adequate blood flow to the heart when compared to patients who received a placebo.

Patients receiving enalapril had 15% fewer cardiovascular events compared with placebo patients, but this finding was not statistically significant.

In one group of 274 patients, Norvasc recipients "showed no significant increase in progression of plaque build-up in coronary arteries," Pfizer said. "Patients receiving placebo showed a significant increase in plaque."