Two Doses of Apixaban for the Extended Treatment of Venous Thromboembolism

Apixaban, an oral factor Xa inhibitor, may provide a simple, fixed-dose regimen for extended treatment of venous thromboembolism.

To compare the efficacy and safety of two doses of apixaban (2.5 or 5 mg twice daily) with placebo for the extended treatment of venous thromboembolism in patients who have completed 6 to 12 months of prior anticoagulant therapy.

This randomized, double-blind study (ClinicalTrials.gov number, NCT00633893) compared two apixaban doses (2.5 or 5 mg twice daily) with placebo for 12 months in patients with venous thromboembolism who had completed 6–12 months of anticoagulation. The primary efficacy outcome was symptomatic recurrent venous thromboembolism or all-cause mortality. Secondary efficacy outcomes included (a) the composite of symptomatic venous thromboembolism or venous thromboembolism-related death, and (b) the composite of symptomatic venous thromboembolism, venous thromboembolism-related death, myocardial infarction, stroke, or cardiovascular-related death. The primary safety outcome was major bleeding; the secondary safety outcome was major and clinically relevant non-major bleeding.

The study included 2486 patients: 829, 840, and 815 randomized to placebo, apixaban 2.5 mg, and apixaban 5 mg, respectively. Rates of the primary efficacy outcome were 11.6% in the placebo group, compared with 3.8% and 4.2% in the apixaban 2.5 mg and 5 mg groups, respectively (absolute risk differences of 7.8% and 7.4%, respectively; 95% confidence intervals 5.3% to 10.3% and 4.8% to 10%, respectively; p<0.001 for both comparisons). Other outcomes are detailed in the Table.

Both doses of apixaban reduced the risk of symptomatic recurrent fatal or non-fatal venous thromboembolism by approximately 80% without increasing the rate of major bleeding. In addition, both apixaban doses reduced arterial thrombotic events. The lower apixaban dose may be preferred for extended treatment, because of the trend for less clinically relevant non-major bleeding.

Agnelli:Bristol Myers Squibb: Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Daiichi Sankyo: Consultancy; Boehringer Ingelheim: Consultancy; Bayer Healthcare: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Sanofi-Aventis: Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau. Buller:Bayer: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; Daiichi: Consultancy, Research Funding; GlaxoSmithKline: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Sanofi-aventis: Consultancy, Research Funding; Roche: Consultancy, Research Funding; Isis: Consultancy, Research Funding; Thrombogenics: Consultancy, Research Funding. Cohen:Astellas: Consultancy, Research Funding; AstraZenica: Consultancy, Research Funding; Bayer: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau; Boheringer-Ingelheim: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau; Daiichi: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau; GlaxoSmithKline: Consultancy, Research Funding; Johnson & Johnson: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau; Mitsubishi Pharma: Consultancy, Research Funding; Pfizer: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau; Portola: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau; Schering Plough: Consultancy, Research Funding; Takeda: Consultancy, Research Funding. Curto:Pfizer: Employment. Gallus:Pfizer: Consultancy, Membership on an entity’s Board of Directors or advisory committees; Bristol Myers Squibb: Consultancy, Membership on an entity’s Board of Directors or advisory committees; Daiichi Sankyo: Consultancy; Bayer: Membership on an entity’s Board of Directors or advisory committees; boehringer-Ingelheim: Membership on an entity’s Board of Directors or advisory committees. Johnson:Pfizer: Employment. Porcari:Pfizer: Employment. Raskob:Pfizer: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Bristol Myer Squibb: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Bayer: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Johnson & Johnson: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Portola: Consultancy; Quintiles: Consultancy; National Blood Clot Alliance: Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau. Weitz:Pfizer: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria.