ANAHEIM, Calif. -- A drug designed to prevent blood clots from developing during a common heart procedure performed so well that the Duke University physicians who tested it predict it will alter medical practice.
The drug eptifibatide (tradename Integrilin) cut deaths and heart attacks by 40 percent in the first 48 hours after it was used in patients who received a balloon angioplasty, which uses a catheter to press artery-obstructing plaque flat, and the implant of a stent, a mesh-like device that props the artery open. Eptifibatide's benefit was consistent in all groups of patients studied in the trial.
The finding is important for patients because eptifibatide is a much more affordable alternative than the only other agent in the class of drugs that has been shown to be effective in preventing clots during the procedure. That drug, abciximab (tradename Reopro), costs $1,500, compared to $400 for eptifibatide.
"Now only about 20 percent of patients being treated with a coronary stent receive platelet inhibitor therapy," said the study's principal investigator, Dr. James Tcheng, a cardiologist at the Duke Clinical Research Institute. "The main reason more patients are not being treated with these drugs is the high cost of treatment.
"Eptifibatide is a more affordable drug which we have now shown to be highly effective in coronary stenting," Tcheng said in an interview. "This could make a dramatic difference in the outcomes of patients treated with a stent angioplasty procedure."
Tcheng prepared the results of the trial, known as ESPRIT (Enhanced Suppression of the Platelet Receptor glycoprotein IIb/IIIa using Integrilin Therapy), for presentation Tuesday at the annual scientific meeting of the American College of Cardiology. ESPRIT was funded COR Therapeutics Inc., and Schering-Plough Corp., developers of eptifibatide.
The trial was halted ahead of schedule in February because an interim analysis showed highly significant reductions in the rates of death or heart attack at both 48 hours and at 30 days. An Independent Data and Safety Monitoring Committee thought it would be unethical to continue to offer only half of patients treatment with eptifibatide when the drug had proved effective.
Nearly 600,000 coronary angioplasty procedures are performed in the United States each year to restore blood flow through blocked arteries, and more than 80 percent of these procedures use stents. But the procedure carries risks – deploying a catheter and stent can disrupt the wall of an artery, and can promote the clumping together of blood platelet cells to form blood clots.
Eptifibatide was given intravenously to patients in the trial immediately before and during an angioplasty, as well as for an average of 18 hours following the procedure. The drug is classified as a "small molecule" inhibitor and works by blocking the key glycoprotein IIb/IIIa receptor on platelets that are responsible for the formation of blood clots. The drug is one of two small molecule inhibitors on the market approved to treat acute coronary syndromes. Of these two, however, only eptifibatide has been tested in stent procedures. Abciximab -- also a platelet inhibitor, but formulated in a different was, as a monoclonal antibody IIb/IIIa platelet inhibitor -- has also been found to be effective in stenting procedures.
ESPRIT was a double-blind, randomized, placebo-controlled trial that enrolled 2,064 patients at 92 hospitals in the United States and Canada. The primary endpoint of the study was at 48 hours; the combined incidence of death, heart attack, urgent repeat angioplasty or coronary artery bypass surgery; or the need for an emergency "bail-out" platelet inhibitor therapy. Researchers found:
- Reduction in endpoint complications by 48 hours was 37 percent between the placebo group (10.5 percent of patients) and the eptifibatide group (6.6 percent of patients).
- Reduction in the number of deaths and heart attacks by 48 hours was 40 percent between the placebo group (9.2 percent of patients) and the eptifibatide group (5.5 percent of patients).
- Reduction in the number of heart attacks to 48 hours was 40 percent between the placebo group (9 percent of patients) and the eptifibatide group (5.4 percent).
- Reduction in the need to perform a second emergency angioplasty procedure or bypass operation by 48 hours was 40 percent between the placebo group (1 percent of patients) and eptifibatide users (0.6 percent).
- Reduction in the emergency use of a glycoprotein inhibitor for thrombolytic "bail-out" to 48 hours was 52 percent between the placebo group (2.1 percent) and the eptifibatide group (1 percent).
There was an increased risk of minor and major bleeding with eptifibatide treatment. The majority of excess bleeding occurred at the point of access into the femoral artery for the angioplasty procedure, Tcheng noted.