A research study published today in the prestigious New England Journal of Medicine shows tremendous promise for a new drug to prevent and treat blood clots. Gary Raskob, Ph.D., Dean of the Hudson College of Public Health at the University of Oklahoma Health Sciences Center, is a member of the leading research team and an author of the publication.
The study was done in patients having knee replacement surgery, and compared a new anti-clotting drug, called abelacimab, with the drug currently given for clot prevention in those patients, called enoxaparin. The results are extremely promising: Patients who received abelacimab saw an 80% reduction in blood clots and had a low risk of bleeding. That’s good news for the future of clot prevention.
“While we have good medications to prevent clotting, the main side effect is bleeding complications,” Raskob said. “Researchers have been searching for new drugs that remain effective at preventing clots, but cause less bleeding. This is an exciting step toward that goal.”
Although patients undergoing various types of surgeries face a risk of blood clots, this study focused on knee replacement surgery. These patients have a high risk of developing clots in the deep veins of their legs, which could then travel to the lungs and prove fatal, if they don’t receive preventive medication. Current drugs like enoxaparin decrease the risk of clots, but increase the odds of bleeding, which could cause an infection in the wound or more serious complications like gastrointestinal or brain bleeding.
The new drug being studied, abelacimab, is a monoclonal antibody and takes a different approach to clot prevention. Blood clotting at the wound site naturally activates during surgery as a step toward healing, especially during an extensive procedure like knee replacement. Clotting itself is a series of complex reactions involving proteins in the blood. One of those proteins, called Factor XI, has begun to stand out to researchers because people who are deficient in Factor XI tend to have less spontaneous bleeding and a lower chance of developing clots later in life. People with inherited Factor XI deficiency, known as hemophilia C, don’t have spontaneous major bleeding complications compared to people with other types of hemophilia.
“This suggested to us that if we reduce Factor XI, we could prevent clots without increasing bleeding complications,” Raskob said. “Abelacimab works by binding to the Factor XI protein in the blood and preventing it from being activated during the clotting sequence.”
The highest risk for blood clots is typically within two weeks after knee replacement surgery, Raskob said. Study participants who received abelacimab had lower levels of Factor XI at 30 days, suggesting a longer period of protection.
“Patients who undergo surgery for hip replacement or removal of cancer have a risk for clots out to one month,” Raskob said. “This study shows that abelacimab has the potential to be effective during the period of time post-operatively when people are at greatest risk.”
The study tested three different doses of abelacimab; the two higher doses were most effective in reducing clots and will be studied in larger research trials to come. Raskob will continue to be involved in these studies, which may include OU Health patients in the future.
