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Snake venom may help treat heart attacks and strokes

Toronto, December 8, 2013

By Geoff Koehler

Dr. Heyu Ni
Dr. Heyu Ni

Using a protein purified from snake venom, a team of researchers has developed a new drug that may prevent blood clots that lead to heart attack and stroke.

The venom comes from a Southeast Asian viper commonly known as a hundred pacer. The snake’s name refers to a local belief that, after being bitten, a victim will be able to walk only 100 steps.

Scientists extract the snake’s venom and filter out all but one protein to create the drug, called Anfibatide.

“Three out of every four Canadians will die from a blood-clotting issue, like deep vein thrombosis, stroke or heart attack,” said Dr. Heyu Ni a principal investigator and scientist in the Keenan Research Centre for Biomedical Science of St. Michael’s Hospital. “That’s more than cancer, infections and every other cause combined. We need more effective treatments and Anfibatide might be one.”

Dr. Ni presented an abstract of his research today at the American Society of Hematology annual meeting in New Orleans.

When a blood vessel’s wall is injured, cells in the blood – called platelets – come together to form a plug and stop the bleeding. Sometimes, however, platelets come together even after the bleeding has stopped, forming clots in blood vessels and preventing blood flow. In the coronary artery, these blockages cause heart attacks; when the clots form in the brain, they lead to strokes.

The drug works by attaching to platelets near the injured wall and controlling their response. Fewer platelets are drawn to the injury but a plug is still formed.

When tested in 94 healthy volunteers, Anfibatide prevented platelets from clotting but didn’t prolong bleeding. This means that the body’s natural response is preserved but there’s a reduced risk of further damage.

“What’s most promising is that this reaction works best when the blood is flowing very fast – exactly the conditions when there is a major blockage,” said Dr. Ni, who is also a scientist with Canadian Blood Services.

There were no obvious side effects, although two volunteers withdrew due to allergy during the initial skin test. A Phase 2 clinical trial for patients who are undergoing angioplasty has begun in China.

This work was partially supported by Lee’s Pharmaceutical Holdings. Two contributing authors are employees of the company – which holds the patent for Anfibatide. Five authors are employees of Zhaoke Pharmaceutical Co. Ltd. All other authors, including Dr. Ni, reported no conflicts of interest.

About St. Michael’s Hospital

St. Michael’s Hospital provides compassionate care to all who enter its doors. The hospital also provides outstanding medical education to future health care professionals in 27 academic disciplines. Critical care and trauma, heart disease, neurosurgery, diabetes, cancer care, care of the homeless and global health are among the Hospital’s recognized areas of expertise. Through the Keenan Research Centre and the Li Ka Shing International Healthcare Education Centre, which make up the Li Ka Shing Knowledge Institute, research and education at St. Michael’s Hospital are recognized and make an impact around the world. Founded in 1892, the hospital is fully affiliated with the University of Toronto.