FDA approves 'super aspirin' for certain heart patients

May 15, 1998
Web posted at: 1:50 a.m. EDT (0550 GMT)

WASHINGTON (AP) -- The Food and Drug Administration on Thursday approved a "super aspirin" to prevent blood clots. The new medicine, inspired by snake venom, could dramatically reduce the risk of heart attacks in people hospitalized with a dangerous type of severe chest pain.

Merck & Co. estimated that if its drug Aggrastat were given to all 1 million Americans hospitalized annually with unstable angina, it could prevent up to 40,000 heart attacks and deaths.

"This is a huge step forward," said Dr. Christopher Cannon, a cardiologist at Brigham & Women's Hospital in Boston.

Unstable angina, a dangerous pain attack, is the leading reason for admitting people to coronary care units. Today, those patients are treated with aspirin and a blood thinner called heparin to help stop the formation of blood clots that can trigger heart attacks. Still, 10 percent to 12 percent of patients go on to have a heart attack, and some die, within a month of developing unstable angina.

Aggrastat is the first in a new class of medicines that, given in addition to heparin and aspirin, appears to cut that risk by about a third.

Unstable angina occurs when years of cholesterol buildup on artery walls suddenly causes a rupture. Blood cells called platelets clump around the wound. As the clot becomes larger, it blocks arterial blood flow to the heart.

These cells are held together by a protein called fibrinogen that hooks onto platelets at sites called glycoprotein IIb-IIIa receptors. Aggrastat works by blocking those receptors -- thus preventing the fibrinogen from gluing together blood clots.

Venom from African Saw-scaled viper used as model

Ironically, Merck modeled the drug on snake venom.

Doctors knew that some snakebite victims bleed to death because the venom contains powerful anti-clotting proteins. Merck and researchers from Temple University in Philadelphia isolated one of those proteins from an African snake called the Saw-scaled viper. Then Merck built the Aggrastat molecule to mimic the snake venom's anticlotting effect, minus the toxins.

Having a new class of drug to treat these complex patients is important, said Dr. James Willerson, medical director of cardiology at the Texas Heart Institute. "It's a different kind of inhibitor, and it certainly has appeared to be effective," he said. "It will get wide use."

"It doesn't dissolve blood clots, but it will help prevent them from growing and causing heart attacks," added Cannon, who has tested the drug.

The FDA, which classified Aggrastat as a priority drug, cautioned that the drug does increase a patient's risk of bleeding. Particularly at risk are patients who go on to need an angioplasty, where a balloon is threaded into the artery to push aside blockage. "But the risk is manageable," said FDA drug chief Dr. Robert Temple.

A similar clot preventer, Centocor's ReoPro, already is used in certain angioplasty patients. But Aggrastat becomes the first novel platelet inhibitor available for the far larger number of unstable angina patients.

Aggrastat, known chemically as tirofiban, would be given intravenously over two to three days during hospitalization. Merck said it will begin shipping it to hospitals next week. A complete two- to three-day dose, dependent on each patient's weight, would cost the hospital $700 to $1,050. Patient costs were not available.

Copyright 1998   The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

Related stories:

• Study: Acetaminophen, warfarin a dangerous combination - March 3, 1998
• Study: Clot-busting drug safe for pulmonary embolism - August 4, 1997
• Blood thinner patients get at-home test - March 13, 1997

Related sites:

Note: Pages will open in a new browser window

• U.S. Food and Drug Administration
• Merck & Co., Inc., Whitehouse Station, NJ
• Centocor

External sites are not endorsed by CNN Interactive.

---

 

---

Sound off on our message boards & chat