AMSTERDAM – In patients with acute venous thromboembolism, 6 months of treatment with the oral-anticoagulant apixaban was as effective as was standard therapy with subcutaneous enoxaparin for a week followed by oral warfarin, and apixaban caused significantly fewer major bleeding complications in a randomized, multicenter trial with more than 5,000 patients.
But in addition to apixaban’s sterling individual performance in this pivotal trial, which seems to clear the way for the drug to eventually receive a labeled indication for acute venous thromboembolism, the results also appeared to further anoint the new, oral anticoagulant roster of dabigatran (Pradaxa), rivaroxaban (Xarelto), and apixaban (Eliquis) as the thrombotic-disease troika to be reckoned with, the newcomers whose time has come.
Dr. Giancarlo Agnelli
Ever since rivaroxaban became the first of the trio to gain acute VTE labeling, last November, physicians who manage patients with acute VTE had to wrestle with the question of how to integrate this option into their practices. The new findings on apixaban suggest that physicians will soon have to think about deciding between rivaroxaban and apixaban for this indication. And since recent results from other major trials also established dabigatran as the equal of warfarin for efficacy when treating acute VTE patients and with superior safety, dabigatran’s entry into acute VTE management seems imminent (N. Engl. J. Med. 2013;368:709-18).
Propelling this new anticoagulant era are the indications of efficacy that’s equivalent with heparin, but safer, and with far easier drug delivery as the need for anticoagulation clinics and regular measurement of international normalized ratio (INR) is eliminated by all three new drugs.
"An oral regimen without laboratory monitoring will simplify therapy," Dr. Giancarlo Agnelli noted when he presented the new apixaban findings at the congress of the International Society on Thrombosis and Haemostasis. Concurrently with his report at the meeting, the results were published online (N. Engl. J. Med. 2013;doi:10.1056/nejmoa1302507).
"I think the argument is overwhelming" to use one of the new drugs instead of warfarin. "They are oral drugs where you do not need a blood draw every 2 or 3 weeks, they are a lot easier to use, and they are at least as good as warfarin and at least as safe," said Dr. Frits R. Rosendaal, professor of clinical epidemiology in hemostasis and thrombosis at Leiden (The Netherlands) University.
The Apixaban for the Initial Management of Pulmonary Embolism and Deep-Vein Thrombosis as First-Line Therapy (AMPLIFY) trial randomized 5,400 acute VTE patients at 358 centers in 28 countries. Patients received either apixaban starting with a 10-mg b.i.d. dosage for 7 days, followed by a dosage of 5 mg b.i.d. for 6 months, or enoxaparin at a dosage of 1 mg/kg every 12 hours for a median of 7 days followed by warfarin for 6 months with a target INR of 2.0-3.0.
The study’s primary efficacy endpoint was the combined rate of recurrent, symptomatic VTE or death related to VTE. This occurred in 59 of 2,609 patients (2.3%) who received apixaban, and in 71 of 2,635 (2.7%) patients who received enoxaparin followed by warfarin. These results met the study’s prespecified criterion for apixaban’s noninferiority to standard treatment reported Dr. Agnelli, professor of medicine at the University of Perugia, Italy.
Major bleeding events occurred in 15 of 2,676 (0.6%) patients on apixaban and in 49 of 2,689 (1.8%) patients on enoxaparin and warfarin, a statistically significant difference. A composite safety outcome of major bleeds plus clinically relevant nonmajor bleeds occurred in 4.3% of the apixaban patients and in 9.7% of the patients on standard therapy, a statistically significant difference. Aside from bleeding events, the rates of all other adverse events were similar in the two treatment arms.
The trial was sponsored by Pfizer and Bristol-Myers Squibb, which market apixaban (Eliquis). Dr. Agnelli disclosed ties to Pfizer, Boehringer Ingelheim, Sanofi, Daiichi Sankyo, and Bayer. Dr. Rosendaal said that he had no disclosures.