Projected 2018 sales: 
$1.463 billion
2012 sales: $1.018 billion

Nexavar has a strong foothold in the liver cancer market, and it's not going away anytime soon. Last year, the standard liver cancer treatment beat out an experimental drug from Bristol-Myers Squibb ($BMY), eliminating the drug's last near-term threat in that market. Two years before that, it topped Sutent in a similar head-to-head liver cancer trial.

Nexavar's foray into lung cancer treatment was not so successful, however. The disease is an especially hard nut to crack, and in May 2012 Bayer and Onyx ($ONXX) said that the drug failed to improve overall survival in a Phase III trial. At that time, Bayer had projected doubling revenue from its approved uses with a lung cancer indication. Bayer has also faced issues with Nexavar in India, where in 2012 it was recognized as an essential but unaffordable treatment and its makers were forced to turn over the know-how for the drug to Indian generics company Natco.

Next up for Nexavar: thyroid cancer. At this year's ASCO conference in June, Bayer and Onyx said they are now looking to file approvals for the disease in the U.S. and Europe, which analysts predict could add about $200 million a year in sales, pushing 2013's top-line mark to about $900 million.

For more:
Bristol-Myers loses to Onyx in PhIII battle of drugs for liver cancer
Bayer's Nexavar hits the brakes on thyroid cancer progression
India sinks Bayer's hopes on Nexavar patent
Bayer's Nexavar falters in another lung cancer trial