July 3, 2003 -- Coreg improves survival in heart failure patients better than another widely used drug. The first study comparing the two beta-blocking drugs assessed future outcome in heart-failure patients.
The Carvedilol or Metroprolol European Trial (COMET) involved more than 3,000 patients in 15 countries, with varying degrees of chronic heart failure -- making it the largest study ever done on either drug. Carvedilol is known as Coreg; metroprolol as Lopressor.
Half of the patients were given Coreg and the other half received Lopressor. They were followed for nearly five years, and didn't know which medication they got.
Considerably Longer Life
By study's end, 34% of Coreg patients had died, compared with 40% of those taking Lopressor -- that's a 17% lower death rate in patients on Coreg. Researchers estimate the average survival was 1.4 years longer in the Coreg group.
The improvement in life expectancy is considerable because this condition has a high death rate despite treatment, writes Henry J. Dargie, in an editorial that accompanies the study in this week's The Lancet.
"It's a fairly clear and definitive result: Carvedilol, in this trial, has been shown to be very much better than metroprolol," lead researcher Philip Poole-Wilson, MD, FRCP, tells WebMD.
Beta-blocker drugs are often used to treat heart failure -- which affects nearly 5 million Americans -- because they slow heart rate, reduce blood pressure, and ease the flow of blood from the heart to the rest of the body. These drugs also are used for high blood pressure, angina, and other cardiovascular problems. They work by blocking "beta" receptors that send chemical messengers to increase heart rate.
Old Still Better Than New?
The COMET findings were presented last week in France at the Heart Failure 2003 meeting of the European Society of Cardiology. There, some questioned why a newer long-acting version of Lopressor, Toprol XL, wasn't used in the study. COMET was sponsored by F. Hoffmann-La Roche and GlaxoSmithKline, which market Coreg in the U.S. and as Dilatrend elsewhere. (GlaxoSmithKline is a sponsor of WebMD.)
Poole-Wilson, professor of cardiology at Imperial College in London, tells WebMD what he told them: The slow-release Lopressor formula -- the more widely used version in the U.S. -- was the only one available when the study began. But two experts not connected with the study say the long-action formula wouldn't likely affect study results.
"The Lopressor formula, taken twice daily was done in COMET, delivers the same dosage of beta-blocking properties as the newer Toprol XL tablet taken once daily," says Howard Eisen, MD, director of the Advanced Heart Failure and Transplant Center at Temple University School of Medicine.
'This Is Really Remarkable'
"This is a significant finding because it shows that one effective drug is better than another effective drug."
The two drugs compared in COMET were "apples and apples," adds Milton Packer, MD, director of the Center for Heart Failure Research and chief of the division of circulatory physiology at Columbia-Presbyterian Medical Center in New York.
"There aren't too many times when physicians and patients are given an opportunity to see a direct head-to-head comparison of two effective drugs, especially on an outcome as important as mortality," he tells WebMD. "This is really remarkable."
So why did Coreg seem so much better? Probably because it does more to help patients with heart failure.
While both Lopressor and Toprol XL block only beta 1 receptor cells, Coreg also blocks beta 2 and other receptor cells -- and also has antioxidative properties and additional effects not found in Lopressor, says Packer.
"Now which one of these additional properties, if any, is responsible for the difference, this trial couldn't determine. But clearly, what this trial shows is that one or more of these additional properties does matter for survival."
Packer is no stranger to the powers of Coreg. He was lead researcher of the COPERNICUS (Carvedilol Prospective Randomized Cumulative Survival) study three years ago that found patients with severe heart failure had a 35% lower risk of dying from their illness when treated with Coreg compared with those who didn't get the drug. In fact, Coreg proved so effective that the study was stopped a year before its expected completion date.
"It had such a striking effect," Packer says. "We calculated it would save one life of every 15 patients treated."