Experimental Blood Thinner May Help Prevent Stroke, Without the Bleeding Risk

Researchers say an experimental stroke drug prevented blood clots without the typical side effect of blood thinners: increased bleeding risk.

Bleeding is a common and potentially dangerous side effect of current anti-clotting drugs used to treat stroke patients. But the new findings suggest that the antiplatelet drug, called ACT017, may be a safe and effective alternative to current therapies used in stroke patients.

“Any way to minimize bleeding risk after administering antiplatelet agents is highly desirable,” said one expert, Dr. Andrew Rogove. He directs stroke services at Northwell Health’s Southside Hospital in Bay Shore, N.Y.

“Further investigation of this promising drug in treatment of acute ischemic stroke is warranted and necessary,” said Rogove, who wasn’t involved in the new study.

This early, phase 1 trial of ACT017 was funded by the drug’s maker, Acticor-Biotech. It included 36 healthy men and women, aged 22 to 65, who were divided into six groups.

Each group received intravenous infusions of the drug over six hours with doses ranging from 62.5 milligrams (mg) to 2,000 mg.

The drug did not significantly extend “bleeding time” — a marker of increased risk for dangerous bleeds, said a team led by Dr. Martine Jandrot-Perrus, a scientist at France’s National Institute of Health and Medical Research.

ACT017 was also well-tolerated at all doses, without serious side effects, her team reported, although a dose of 2,000 mg was most effective. The most common side effects were mild to moderate headache and head discomfort.

The findings were published April 18 in the journal Arteriosclerosis, Thrombosis and Vascular Biology.

Jandrot-Perrus said there is a clear need for a drug to treat acute stroke that prevents clotting without increasing the risk of bleeding.

ACT017 inhibits blood platelet clumping and clot formation by targeting a protein in platelets that plays a critical role in clot formation, the researchers explained.

“Our results are quite encouraging because they show the candidate compound is well-tolerated at doses even twice as high as the ones targeted for a future treatment and without any signs of bleeding,” Jandrot-Perrus said in a journal news release.

She said the drug’s action on platelets is fast, specific and largely reversible within 24 hours.

Another U.S. stroke expert agreed that doctors have long sought better, safer blood thinners.

“The biggest impediment to removal of clots has always been the risk of bleeding that each treatment carries with it,” said Dr. Salman Azhar, director of stroke care at Lenox Hill Hospital in New York City.

Azhar explained that ACT017 seems to “prevent formation of clots on the inner lining of the exposed blood vessel — as is found in strokes and heart attacks — without interfering with the ability of platelets to prevent bleeding elsewhere in the body if needed.”

But he said more study — in actual stroke patients — is needed.

“The caveat here is, of course, that this study was in normal volunteers without a clot and/or damaged brain tissue,” Azhar said.

More information

The American Stroke Association has more on anti-clotting drugs.