New Heart Attack Drug Joins Arsenal
Eplerenone works by blocking a hormone
MONDAY, March 31, 2003 (HealthDayNews) -- Heart attack patients with heart failure who added a new drug to their daily regimen significantly reduced their risk of death and of being hospitalized.
The findings, from a large international study, could signal the beginning of a new era in treating patients with different heart conditions. "A lot of people felt that if patients were on ACE inhibitors and beta blockers, we had done everything we could, that we had exhausted that strategy," says study author Dr. Bertram Pitt, a professor of medicine at the University of Michigan School of Medicine. "This is also important, and it may have implications for heart failure and heart attacks and maybe lots of other cardiovascular disease."
The findings will be released March 31 at the annual scientific sessions of the American College of Cardiology in Chicago. They also appear in the April 3 issue of the The New England Journal of Medicine.
The drug, which goes by the generic name eplerenone and the brand name Inspra, works by blocking the action of the hormone aldosterone. Although eplerenone was recently approved by the U.S. Food and Drug Administration to treat high blood pressure, it is not yet approved to treat heart attack patients.
Scientists have known about the hormone aldosterone for half a century but did not realize its significance in heart health until recently. "It's an old friend, but no one thought it was very important," Pitt says. "It's been a neglected friend. No one knew it was so important."
Not until 1999, anyway, and the publication of results from a trial called RALES, also led by Pitt. The RALES study showed that another drug, spironolactone, which blocked the same hormone, reduced deaths by 30 percent and hospitalizations by 35 percent in patients with severe heart failure. Spironolactone is now commonly used for heart failure patients.
In the new trial, 6,632 patients in 37 countries were randomized to receive eplerenone (25 milligrams a day to start, moving to 50 milligrams a day after one month) or a placebo. Most of the patients also received standard therapies for their condition, namely ACE inhibitors (taken by 87 percent of the participants), beta blockers (75 percent), aspirin (88 percent) and diuretics (60 percent). All of the patients had had a heart attack three to 14 days before enrolling in the study and had to have problems with the functioning of their left ventricle. They were followed for a mean of 16 months.
Individuals taking eplerenone had 15 percent fewer deaths compared to the placebo group, and 13 percent fewer cardiovascular-related deaths and cardiovascular hospitalizations.
The differences were even more striking among participants who were taking other therapies (including an ACE inhibitor, beta-blocker, aspirin and statin) and who had undergone coronary reperfusion, a procedure to improve blood flow. They experienced a 26 percent reduction in mortality. This group also experienced a 21 percent overall reduction in sudden cardiac death and 15 percent fewer hospitalizations for heart failure.
The fact that eplerenone also reduced the incidence of sudden death calls into question the usefulness of defibrillators. "Maybe this drug can help to reduce sudden death and in a lot of people we won't need a defibrillation," Pitt says. "It's very expensive to put a defibrillator in people."
It's not clear exactly why eplerenone is effective, and it's likely that more than one mechanism is at work. More studies will be needed to determine this and also to pinpoint which populations will benefit from the drug. This trial's population was 90 percent white and 71 percent male, so minorities and women were not represented.
Researchers are also anxious to see what other conditions the drug might treat. "I think eplerenone will have a direct impact on people with heart attack and maybe also with people with not-so-bad [heart] function," Pitt says. People with high blood pressure, hypertension, renal disease, valvular disease and diabetes may also be helped. "There are lots of applications for this," Pitt says.