Apixaban appears as effective as conventional therapy for acute VTE
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An apixaban regimen was found to be noninferior to conventional therapy — enoxaparin followed by warfarin — for the treatment of acute venous thromboembolism, according to the findings of a randomized, double blind study.
However, apixaban (Eliquis, Bristol-Myers Squibb) was associated with significantly less bleeding.
Conventional treatment consisting of enoxaparin and warfarin has been shown effective in patients with acute symptomatic VTE, but it also presents a challenge due to enoxaparin requirements of daily subcutaneous injections, as well as monitoring coagulation and adjusting dosages in warfarin therapy.
In prior studies, apixaban has been shown to be effective for the prevention of recurrent VTE in patients who have completed 6 to 12 months of anticoagulant therapy for acute VTE, with similar rates of major bleeding associated with placebo.
To determine the efficacy of an alternative apixaban regimen, researchers enrolled 5,395 patients with acute VTE to receive either 10 mg apixaban twice daily for a week, followed by 5 mg twice daily for 6 months, or conventional therapy, consisting of enoxaparin followed by warfarin.
Primary efficacy outcomes of the study included recurrent symptomatic VTE or VTE-related mortality.
Eligible patients included those who were aged at least 18 years and had objectively confirmed symptomatic proximal deep vein thrombosis (thrombosis involving at least the popliteal vein or a more proximal vein) or pulmonary embolism (with or without DVT).
According to study results, the primary efficacy outcome of recurrent VTE occurred in 59 of 2,609 patients (2.3%) in the apixaban group and in 71 of 2,635 (2.7%) in the conventional therapy group, for an RR with apixaban of 0.84 (95% CI, 0.60-1.18).
The difference in risk (apixaban minus conventional therapy) was −0.4 percentage points (95% CI, −1.3 to 0.4).
“For the treatment of acute venous thromboembolism, the [Apixaban for the Initial Management
of Pulmonary Embolism and Deep-Vein Thrombosis as First-Line Therapy] study showed that a fixed-dose regimen of oral apixaban alone was as effective as conventional treatment consisting of enoxaparin followed by warfarin and was associated with a clinically relevant reduction of 69% in major bleeding,” the researchers wrote.
In addition, major bleeding occurred in 15 of 2,676 patients (0.6%) in the apixaban group and in 49 of 2689 (1.8%) in the conventional therapy group, for an RR of 0.31 (95% CI, 0.17 to 0.55). The difference in risk was −1.1 percentage points (95% CI, −1.7 to −0.6).
Mary Cushman
In an accompanying editorial, Mary Cushman, MD, MSc, professor of medicine at University of Vermont in Burlington, wrote, “New anticoagulants are not for every patient, and there is ongoing research to optimize the use of vitamin K antagonists, so it is unlikely that these will disappear from practice. [However] as we translate knowledge from the era of vitamin K antagonists to new agents, it is critical that we consider the factors discussed here.”
“More information is needed on reversal strategies, monitoring (e.g., in the presence of interacting drugs, extremes of patient weight, or bleeding or thrombosis complications), approaches to treatment failure, comparisons of adherence to treatment among new drugs and warfarin, and formal cost-effectiveness analyses. Comparative-effectiveness studies and postmarketing surveillance are key.”