18. Eliquis

Bristol-Myers Squibb and Pfizer
2015 sales: $1.86 billion
2020 projection: $4.25 billion

Eliquis may have gotten off to a slow start that disappointed analysts. But lately, the new-age anticoagulant has come roaring back, thanks to pumped-up investments from its makers.

Most recently, the med posted $602 million in Q4 sales for Bristol-Myers Squibb ($BMY), which shares it with Pfizer ($PFE), to double its haul from the same period in 2014. Full-year sales increased even more than twofold, too. And the therapy now leads its classmates in new-to-brand patient share in cardiology in 12 markets around the world.

With that recent momentum, Bristol CEO Giovanni Caforio doesn't think it'll be long before Eliquis overtakes hefty competitors Xarelto, from Johnson & Johnson ($JNJ) and Bayer, and Boehringer Ingelheim's Pradaxa. The company is "well on our way" to becoming No. 1 in the class, Caforio told investors on the company's Q1 conference call.

But competitors may have a thing or two to say about that--as well as their own strategies to fight off rivals. Xarelto, for one boasts an extensive clinical trial program that's put it at the top of the charts when it comes to its list of indications. And right now, Pradaxa is the only next-gen blood thinner with an FDA-approved reversal agent, Praxbind. -- Carly Helfand (email | Twitter)

For more:
Bristol-Myers immunotherapies soar, but Eliquis haul tops the charts
How can Pradaxa, Xarelto and Eliquis finally unseat warfarin? Safety data, analyst says
Patient education 'useless' when it comes to Eliquis adherence: study
Should Eliquis' surge make Xarelto fans very, very afraid? Not really, analyst says

18. Eliquis