Research Targets Improved Prevention of Recurrent Blood Clots
Tuesday, December 11, 2012 - Campus News - Contact Theresa Green, (405) 833-9824
New research shows a simple, fixed dose regimen of a newer medication is effective for extended treatment of venous thromboembolism.
"Venous thromboembolism is a condition in which blood clots form in the large veins in the leg. They can grow, break free and travel through the circulation to the lungs where they can cause serious cardio-respiratory problems and even death," said Gary Raskob, Ph.D., a steering committee member for the study and dean of the University of Oklahoma College of Public Health.
There are an estimated 900,000 cases of VTE in the United States each year, including 100,000 to 300,000 deaths. Many of these may represent recurrent disease.
Now, researchers believe their work provides important information on the safety and effectiveness of an easy-to-use treatment aimed at preventing recurrent VTE.
The randomized, double-blind study involved 2486 patients at 328 sites in 28 countries. It compared the safety and efficacy of two different doses (2.5 mg and 5 mg) of the drug apixaban to placebo in patients with VTE who had completed six to 12 months of anticoagulation and for whom treating physicians were uncertain about the need for continuing anti-clotting therapy.
Apixaban is an oral factor Xa inhibitor given in fixed dozes without laboratory monitoring. It inhibits activated factor Xa, an enzyme that plays a critical role in the body's clotting ability.
The study found that apixaban reduced the risk of recurrent fatal or non-fatal VTE in patients without increasing bleeding side effects.
"These findings show that when there is uncertainty about the benefit and risk for continued therapy in patients with venous thromboembolism, there is good rationale for an additional 12 months of anticoagulation," Raskob said. "In addition, it showed that both doses were effective, safe and simple to use."
Raskob said it is important to note that only 15 percent of the patients in the study were 75 years of age or older, and few had a body weight of less than 132 pounds or moderate to severe renal impairment. Further study will be needed to determine the potential benefits and bleeding risk of using apixaban in such patients.
"The data suggest that the disease burden from recurrent cases of VTE may be reduced even further by extending treatment with apixaban even beyond 18 to 24 months. However, additional study is needed to determine the potential benefits and risks of such longer-term treatment with this medication," Raskob said.
The trial was funded by Bristol-Myers Squibb and Pfizer Inc., but the steering committee had final responsibility for study design, protocol development, study oversight, data verification and analyses. The protocol also was approved by the Institutional Review Board for each center.
The study results will be presented this week at the American Society of Hematology meeting in Atlanta. The New England Journal of Medicine has also published it online.
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