New data backs Pfizer's Eliquis in atrial fibrillation

New data from the huge ARISTOTLE trial of Pfizer and Bristol-Myers Squibb's anticoagulant Eliquis in patients with non-valvular atrial fibrillation (AF) have reinforced the benefits of the drug.

The latest results from the 18,000-patient study - published online on The Lancet's website - indicate that Eliquis (apixaban) was more effective than warfarin at preventing clinical events including stroke, bleeding, and mortality.

In the sub-analysis, the investigators stratified patients for baseline risk using a number of risk-rating scales, but found that Pfizer's drug consistently outperformed warfarin regardless of the patient's risk of stroke or bleeding.

In patients at risk of bleeds the benefit of using Pfizer and BMS' drug was even greater than for those at lower risk, according to the researchers. 

That is a major finding, as doctors have to exercise considerable caution when considering anticoagulant therapy in patients with AF, weighing up the risk of thromboembolism with the risk of drug-related bleeding episodes.

To help make that decision, clinicians use a range of measures to gauge patient risk - including CHADS₂, CHA₂DS₂-VASc, and HAS-BLED scores - in line with the recommendations of the European Society of Cardiology (ESC) AF guidelines.

In an editorial accompanying the study, Dr Vassilis Vassiliou and Dr Paul Flynn of Cambridge University NHS Trust note that "after many years of searching, physicians might now face a less agonising choice on behalf of high-risk patients". 

Earlier data from the study - which underpinned Pfizer and BMS' marketing applications for Eliquis - demonstrated a 21 per cent reduced risk of stroke or systemic embolism for patients taking Eliquis compared to warfarin, as well as a reduced risk in major bleeding by 31 per cent and mortality by 11 per cent.

The new findings bode well for the commercial prospects of Eliquis, which has already been given a green light in Europe for the prevention of venous thromboembolic events (VTE) in adult patients who have undergone elective hip or knee replacement surgery, and recommended for approval in the AF indication.

Its path to approval in the US has been a little rockier, however, with the FDA asking for more information on data management and verification in the ARISTOTLE trial earlier this year, although a re-filed application has now been accepted with an action date of March 13, 2013.

Eliquis' clinical profile has prompted predictions of blockbuster sales of up to $4bn at peak, representing a large share of an AF market currently estimated at around $9bn a year.

If approved in AF the drug will compete in the marketplace with Johnson & Johnson and Bayer's Xarelto (rivaroxaban) and Boehringer Ingelheim's Pradaxa (dabigatran etexilate mesylate).