20. Bristol-Myers Squibb

Immuno-oncology was the story at Bristol-Myers Squibb in 2015. Industry analysts expect recent launch Opdivo to be the third-biggest-selling drug in the world — with annual sales of $11.1 billion — by 2020. By the end of 2015, Opdivo was approved in 43 countries and became the first PD-1 inhibitor approved for the treatment of the most common type of kidney cancer. The drugmaker said physicians have been prescribing Opdivo to more than 60% of new eligible U.S. lung-cancer patients since it received approval for the additional indication in March, outpacing Merck's Keytruda. Indeed, Everscore ISI analyst Mark Schoenebaum characterized the uptake as happening “very rapidly.” The FDA also approved an indication for Opdivo to be used in combination with Yervoy to treat metastatic melanoma. Beyond oncology, Orencia and Eliquis remained key revenue drivers in 2015. On another front, BMS sold its pipeline of investigational HIV medicines to ViiV Healthcare in order to focus on other therapeutic areas.