DALLAS, June 23 -- In a growing class of blood-thinning drugs to treat heart attack, researchers have found one that seems to have a greater long-term benefit rather than only an immediate effect, according to a study released in today's Circulation: Journal of the American Heart Association.
The drug, lamifiban, is in a class of drugs called "platelet IIb/ IIIa receptor blockers," which prevent platelets from forming blood clots that obstruct blood vessels and cause heart attacks. Through a different mechanism, aspirin has a much weaker effect on platelets.
Lamifiban was used alone in varying doses and in combination with heparin, a blood-thinning agent.
The new drug combination may be used to treat patients who have severe chest pain or have had a non-Q-wave, or limited, heart attack. Standard in-hospital treatment for these individuals involves aspirin and heparin.
The study, co-authored by David J. Moliterno, M.D. is among several that are looking into ways to reduce heart attack survivors' high risk for death or a second heart attack in the first year following the attack, with the most critical period being in the first few weeks.
His study is unique in that it suggests a long-term benefit rather than an immediate effect alone. Even with standard treatment, "There is still room for improvement," says Moliterno, of the department of cardiology at The Cleveland Clinic Foundation, Cleveland, Ohio. The number of deaths and second heart attacks is high even at six months after the initial attack, he says.
The Circulation report, however, indicates that if heart attack patients survive the first 30 days, the chances of surviving past six months or even a year are better if they receive lamifiban compared with standard treatment.
"We don't know specifically how long before each individual patient is stabilized after a heart attack," says Moliterno. "Most deaths and second heart attacks tend to occur in the first few days or weeks, but there's more than a 50 percent increase in these events between 30 days and six months, regardless of current therapy."
The study involved 2,282 hospitalized patients in 20 countries. Patients were assigned one of the following drug combinations: low-dose lamifiban with or without heparin, high-dose lamifiban with or without heparin, or standard heparin alone therapy. All patients received aspirin.
"The additive role of heparin remains uncertain, but appears more favorable with low-dose lamifiban," Moliterno says.
After 30 days there was a minor difference in the number of deaths or second heart attacks among the low-dose lamifiban, high-dose lamifiban, and standard groups. However, after six months, the individuals taking low doses of lamifiban were 23 percent less likely to die or have second heart attacks. When compared with the standard heparin only treatment, a combination of low doses of lamifiban and heparin reduced the number of deaths or second heart attacks by over 30 percent.
Researchers say the study has yielded "very encouraging" results, and a more focused study using specific doses of lamifiban, based on each patient's height and weight, is underway. Further study will also explore the extent of benefit that lamifiban treatment offers at different follow-up intervals.
The FDA does not yet approve lamifiban.
Co-authors of the study are scientists and doctors participating in the Platelet IIb/ IIa Antagonism for the Reduction of Acute coronary syndrome events in a Global Organization Network (PARAGON) trial.
Media advisory: Dr. Moliterno may be reached by calling (216) 444-2121; fax (216) 445-4363. (Please do not publish telephone or fax numbers.)