OU Public Health Dean Is Senior Author for Global Study of New Drug to Prevent Blood Clots

Blood clots are a major concern for people facing various health situations, including surgery, hospitalization and cancer. While current medications lower the risk of clots, they increase the chance of bleeding complications, to an extent that some people cannot take them. However, a new option may be on the horizon — a research study published today in the prestigious New England Journal of Medicine shows promise for a new oral medication that is effective for preventing clots without increasing bleeding.

Gary Raskob, Ph.D., Dean of the Hudson College of Public Health at the University of Oklahoma Health Sciences Center, is senior author of the publication and chair of the steering committee for the study. The study tested the drug Milvexian in patients undergoing knee replacement surgery, who have a high risk of developing clots in the deep veins of their legs. More than 1,200 patients undergoing surgery at 118 health centers in 18 countries participated in the trial. Results showed that a daily dose of 100 milligrams or more of Milvexian was more effective for preventing clots than the current standard of treatment and, importantly, it had a low risk of bleeding.

“We are encouraged by these initial results with this new oral anticoagulant that works differently from existing medications,” Raskob said. “We may finally be able to realize the longstanding goal of separating the benefit of anticoagulant medication for preventing clots from its side effect of increasing bleeding complications.”

There is an enormous need for drugs to prevent clots — two of the top 10 drugs sold across the world are anti-clotting medications, Raskob said. Blood clots can cause serious illness and disability. As the underlying cause of most heart attacks and strokes, and of clots in the legs that move to the lungs, they are responsible for about 1 in 4 deaths worldwide. Blood clots in the lungs, known as pulmonary embolism, are fatal for about 100,000 people each year in the United States, according to the Centers for Disease Control. Because so many people require the medications to reduce the risk of clots, researchers are devoting significant time and resources to developing new therapies that are effective and improve patient safety.

Researchers chose the drug Milvexian to study because of the way it reacts with a protein in the blood called Factor XI. People who have a genetic deficiency of Factor XI (a condition known as hemophilia C) have a lower chance of developing clots later in life, and they don’t have spontaneous bleeding complications compared to people with other types of hemophilia. This suggested to researchers that if Factor XI could be reduced in at-risk patients, clots could be prevented without bleeding complications. Milvexian works by binding to Factor XI and inhibiting it, which reduces the risk of clot development.

Although researchers studied Milvexian in patients undergoing knee replacement surgery for this clinical trial, future trials will focus on other types of patients who require anti-clotting medication. “A few examples include people with atrial fibrillation who are at risk of a stroke, people with cancer-associated thrombosis who have a high risk of bleeding, and people who’ve had a stroke and need treatment to prevent a second stroke,” Raskob said.

Most of Raskob’s research career has been devoted to the prevention, diagnosis and treatment of blood clots, formally called deep-vein thrombosis, as well as pulmonary embolism, a blockage that occurs when part of a clot breaks off and travels through the bloodstream to the lungs. In July, he was an author for another publication in the New England Journal of Medicine about abelacimab, a monoclonal antibody injected under the skin, which also targets Factor XI for the prevention of clots.