Bristol-Myers Squibb Co. and Pfizer Inc. on Thursday said their blood thinner apixaban was more effective than Sanofi-Aventis' Lovenox in a late stage clinical trial.
The study compared the drugs' ability to reduce blood clots in the legs or lungs, also called venous thromboembolisms, along with deaths in patients undergoing knee replacement operations.
Apixaban is given by mouth, and is considered to be a potential blockbuster drug. Enoxaparin is marketed under the names Lovenox and Clexane.
Pfizer and Bristol-Myers said 40 to 60 percent of knee replacement patients have a thromboembolism unless they receive preventive care before surgery. Venous thromboembolisms include deep vein thrombosis, or blood clots in veins that usually occur in the leg, or a pulmonary embolism, or blood clot in the lungs.
In the trial, about 3,200 patients were given either 2.5 milligrams of apixaban twice a day, or a daily 40-milligram injection of enoxaparin. The companies said 15.1 percent of the apixaban patients had a thromboembolism, a nonfatal pulmonary embolism, or died from any cause. For the enoxaparin patients, 24.4 percent had at least one of those events. That was significant enough to meet the goals of the trial.
The data comes from around 2,000 of the patients in the study.
Pfizer and Bristol-Myers said apixaban reduced the risk of major venous thromboembolism by half. They said 1.1 percent of the patients who took apixaban had one, compared to 2.2 percent of patients on enoxaparin.
Apixaban did not significantly reduce bleeding.
The safety of the two drugs was said to be comparable, as both drugs raised levels of a liver enzyme in about 2 percent of patients.