In drug development, the devil is often in the details. But for Pfizer (NYSE: PFE) and Bristol-Myers Squibb's (NYSE: BMY) new atrial fibrillation treatment, Eliquis, the devil seems to have left the building.

In June, the duo released top-line data that Eliquis beat warfarin, the current standard of care for atrial fibrillation. But it wasn't until the full data was published in The New England Journal of Medicine and presented at the European Society of Cardiology Congress medical meeting this weekend that investors could be confident that the data are solid.

Eliquis is in a three-horse race to replace warfarin, a drug that most cardiologists would gladly give up if something better came along. The active ingredient is used as a rat poison because ingesting too much will cause internal bleeding. Normally, brand-name drugs have trouble competing against an established cheap generic, but in this case, warfarin seems ripe to be picked off.

Eliquis is actually behind Boehringer Ingelheim's Pradaxa, which is already on the market for atrial fibrillation, and Bayer and Johnson & Johnson's (NYSE: JNJ) Xarelto, which is on the market to replace Sanofi's (NYSE: SNY) Lovenox for blood clots and should get a decision from the Food and Drug Administration by the end of the year about being marketed as a treatment for atrial fibrillation.

But Eliquis has the best data in atrial fibrillation to date and is the only drug to prove that it's superior to warfarin. The full data set didn't change that view and didn't offer any new revelations that might scare doctors away from making it the new standard of care.

How much is the superiority data worth? Billions per year certainly is not out of the question. The entire warfarin-replacement market could be worth $20 billion by the end of the decade, and if Lucifer remains out of the way, it sure looks like Eliquis could take a substantial chunk of that.

Interested in keeping track of Pfizer and Bristol-Myers as they try to get Eliquis approved? Click here to add both stocks to My Watchlist, which will help you keep track of all our Foolish analysis on the companies.

Fool contributor Brian Orelli holds no position in any company mentioned. Click here to see his holdings and a short bio. The Motley Fool owns shares of Johnson & Johnson. Motley Fool newsletter services have recommended buying shares of Johnson & Johnson and Pfizer, as well as creating a diagonal call position in Johnson & Johnson. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.