PARIS - An experimental anti-clotting drug from Bristol-Myers Squibb and Pfizer reduced deaths more than standard treatment warfarin in a major study, giving it a potentially important edge over rivals.
Although Eliquis will be third to market among a wave of new oral anticoagulants, the data presented at Europe's biggest medical meeting on Sunday means it could now be viewed as the best in class.
People with dangerously irregular heart rhythms given Eliquis were 21 per cent less likely to suffer strokes than those on decades-old warfarin, a problematic drug first developed as rat poison that requires regular blood tests.
It also produced a 31 per cent relative reduction in the risk of major bleeding - especially bleeding in the brain - and an 11 per cent reduction in risk of death from any cause, results from a big 18,000-patient clinical study showed.
Although the mortality benefit only just reached statistical significance, the finding puts Eliquis ahead of its two key rivals by showing superiority to warfarin when it comes to saving lives.
That is likely to be seized on by Bristol and Pfizer in an upcoming marketing fight with Boehringer Ingelheim's Pradaxa - currently the only approved alternative to warfarin in stroke prevention - and Xarelto, from Bayer BAYGn.DE and Johnson & Johnson, which is expected to be approved shortly.
"It gives a lot of confidence when you see a drug that reduces mortality. That's another feather in the cap," said Dr Chris Granger of Duke University Medical Center, who led the study.
The result means that giving Eliquis rather than warfarin for 1.8 years - the average length of the study - would prevent eight deaths for each 1,000 people treated.
All three new drugs are vying for a share of a warfarin-replacement market that industry analysts estimate could be worth US$10-US$20 billion (S$12-S$24 billion) a year by the end of the decade.
Currently, analysts surveyed by Thomson Reuters Pharma expect sales of US$1.6 billion for Eliquis, or apixaban, which is due to be submitted for regulatory approval later this year.
That is less than the US$3 billion forecast for Xarelto and some predict the balance in future may shift more towards Eliquis and away from Xarelto given the latest strong data.
Excitement over Eliquis has grown since June when headline results showed it was better and safer than warfarin. How much better, however, only became clear on Sunday when the actual data was unveiled at the European Society of Cardiology annual meeting and published in the New England Journal of Medicine.
In an editorial in the journal, Dr Jessica Mega of Boston's Brigham and Women's Hospital said the results were "impressive"but she cautioned it was difficult to make comparisons between different drugs, due to variations in the clinical trials.
Death of warfarin?
Doctors attending the ESC meeting said the new drugs would upend the landscape for treating patients with atrial fibrillation, whose irregular heartbeats can cause blood to pool, increasing their risk of blood clots and strokes.
"It is another dagger in the heart for warfarin as an anticoagulation treatment for patients with atrial fibrillation to prevent stroke," said Dr Ralph Brindis.
Brindis, a senior adviser for Northern California Kaiser Permanente and immediate past president of the American College of Cardiology, said Eliquis had scored a "home run", although it and the other new anticoagulants still faced challenges.
In particular, he is concerned about adherence to medical treatment among elderly patients, as doctors may be less able to ensure they are taking drugs correctly once they do not need regular blood tests. For such patients, once-daily Xarelto may be a better bet than twice-daily Eliquis or Pradaxa.
Dr Michael Boehm from Germany's University Hospital of Saarland, who chairs the ESC's scientific programme committee, said the advent of new oral anticoagulants would change clinical practice "immensely".
Still, many cardiologists in Paris said they would not rush to switch existing patients who are well-controlled on warfarin - a cheap generic medicine - to the new and expensive branded products.