3. Opdivo

Bristol-Myers Squibb
PD-1 immuno-oncology treatment
2015 sales: $942 million
2020 sales: $8.4 billion

It might seem remarkable that within in the next 5 years a brand-new drug would become the third bestselling med in the world, and soar from zero to $8.4 billion with breakneck speed. But then Bristol-Myers Squibb's ($BMY) Opdivo is turning out to be a remarkable drug.

The cancer treatment was approved ahead of schedule right before Christmas in 2014 and has proved to be a gift that keeps on giving. It is a PD-1 inhibitor, so it interferes with a mechanism cancer cells use to escape detection by the body's immune system, and as such can be targeted at a variety of cancers. It was initially approved for treating melanoma but that was quickly followed by an FDA nod for treating non-small cell lung cancer. In October it won FDA approval to treat squamous non-small cell lung cancer (NSCLC) and then in October won approval for non-squamous NSCLC. It also performed so well in a late-stage kidney cancer study, displaying such a survival advantage over Novartis' ($NVS) Afinitor, that the monitoring committee stopped another trial early.

And BMS expects much more. The company reported in March that it is testing Opdivo on "multiple tumor types consisting of more than 50 trials--as a monotherapy or in combination with other therapies" with more than 7,000 patients globally.

Along its soaring trajectory Opdivo is expected to surpass Merck's ($MRK) Keytruda, also a PD-1 inhibitor which got its approval three months ahead of Opdivo. The two have been tracking neck and neck in approvals, and Merck has said it has more than 85 clinical trials underway across more than 30 tumor types among 14,000 patients, also alone and in combination with other drugs. But EvaluatePharma's projections put its sales in 2020 at just under $5 billion, which is not too shabby, but which places it at 19 on the list, far below Opdivo. Eric Palmer (email | Twitter)

For more:
How does the Keytruda-Opdivo marketing battle stack up?
Merck's Keytruda, BMS' Opdivo score European nods to keep immuno-oncology race blazing
BMS scores positive EMA opinion for Opdivo in advanced melanoma patients
BMS leapfrogs Merck with Opdivo approval in lung cancer
The PD-1 wave? Report says it's a $33B tsunami, with BMS surfing for first place

3. Opdivo