New drug may lower blood clot risk following surgery, study finds

A new drug targeting a blood protein may lower the risk for blood dangerous clots, a study has found. Photo by Qimono/Pixabay
A new drug targeting a blood protein may lower the risk for blood dangerous clots, a study has found. Photo by Qimono/Pixabay

July 19 (UPI) -- The drug abelacimab prevents blood clots in patients undergoing knee replacement surgery, a study published by the New England Journal of Medicine found.

Abelacimab, developed by Cambridge, Mass.-based Anthos Therapeutics, reduced the risk for blood clots in people who had the procedure by about 80% compared with the blood-thinner enoxaparin, the data showed.


The drug's effects appear to last for up to a month following surgery, the researchers said.

The discovery could offer people with or at risk for blood clots, including some victims of strokes, a potentially game-changing treatment, they said.

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"Patients who undergo knee replacement routinely receive anti-clotting treatment with enoxaparin or other anticoagulant medications that require daily administration," study co-author Dr. Jeffrey Weitz said in a press release.

"With a single injection of abelacimab after surgery, we found much better protection against clots in the veins in the leg compared with enoxaparin, one of the current standards of care," said Weitz, a hematologist and professor of medicine at McMaster University in Hamilton, Ontario, Canada.

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Enoxaparin is a commonly used blood-thinner sold under the brand name Lovenox, while abelacimab is a new drug currently in clinical trials, according to the researchers.


As their name suggests, blood-thinners, known formally as anticoagulant and antiplatelet drugs, are designed to improve blood flow and prevent clots.

Abelacimab is an antibody that binds to clotting factor XI, a protein that helps blood to clot, and prevents its activation, thereby halting clot formation.

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For this study, which was funded in part by Anthos, the makers of the new drug, Weitz and his colleagues compared the two blood-thinners in 412 patients who had knee replacement surgery.

New anti-clotting medications are often first tested on patients undergoing orthopedic surgery, such as knee replacement, because these patients are at risk for clots in the veins of their operated leg, Weitz said.

Therefore, different doses of the drug can be evaluated to identify those that are both effective and safe compared with currently used medications such as enoxaparin.

These doses can then be carried forward into studies of patients with clots or at risk of clots, such as cancer associated clots or stroke prevention in patients with atrial fibrillation, or AFib, according to Weitz.

Study participants were closely monitored for symptoms or signs of clotting or bleeding and underwent an X-ray of the veins of the operated leg to detect any possible clot formation.


Factor XI is indeed a key driver of clot formation following surgery, based on the study findings, Weitz said.

The fact that abelacimab was more effective than enoxaparin, which inhibits clotting factors downstream to factor XI, highlights the importance of factor XI in clot formation, he said.

"This success of abelacimab in this study provides the foundation for its use for prevention of stroke in patients with atrial fibrillation and for treatment of deep-vein thrombosis and pulmonary embolism, clots in the veins of the leg and clots in the lung, in patients with cancer," Weitz said.

"We expect factor XI to be a safer target for new anticoagulants than the targets of currently available anticoagulants because patients with congenital factor XI deficiency are at reduced risk for clots but rarely have spontaneous bleeding," he said.

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