University of Copenhagen researchers found that apixaban reduced thromboembolism and death by 9 per cent compared with enoxaparin in knee replacement patients.
Apixaban, a factor Xa inhibitor, was associated with no additional risk of bleeding.
The treatment was also more convenient for patients, the researchers showed, because it removed the need for the regular injections required with some anti-thrombolytic treatments.
Dr Michael Lassen and colleagues assessed the efficacy of apixaban in a randomised, double-blind phase III study.
A total of 3,057 patients undergoing knee replacement surgery were randomised to receive either apixaban or enoxaparin.
Half received oral apixaban 2.5mg twice daily, started 12-24 hours after surgery. The other half were given enoxaparin 40mg daily, started 12 hours before surgery.
Patients followed drug regimens for 10-14 days after surgery and were assessed daily for DVT, pulmonary embolism and all-cause death, which were defined as primary outcomes in the study, and for bleeding.
Asymptomatic DVT was investigated at the end of treatment with venography.
Among the 1,973 patients eligible for analysis, 15 per cent of apixaban-treated patients developed primary outcomes compared with 24 per cent treated with enoxaparin. There was no increased risk of bleeding in the apixaban group.
The findings may help address difficulties balancing the risk of bleeding with efficacy of anticoagulants, said authors.
Apixaban treatment 'offers a convenient and more effective orally administered alternative' to enoxaparin, without increased bleeding, they said.