18. Avastin

Amgen and Allergan have an approved Avastin biosimilar, while Pfizer is waiting on an FDA decision expected in June. (Roche)

18. Avastin
2018 U.S. sales: $2.9 billion
Used for: kidney cancer, cervical cancer, ovarian cancer, colorectal cancer, non-small cell lung cancer

With a new approval to treat first-line ovarian cancer under its belt, Roche's Avastin may have expected growth in the U.S. market, but 2018 saw the blockbuster mostly tread water in terms of sales.

In 2018, Avastin cleared $2.87 billion in the U.S., a roughly 1% increase over the previous year. Though it did make inroads with its newest approval, Avastin also suffered from competition in first-line lung cancer, which largely offset the drug's U.S. growth, Roche said.

Still, overall, those sales helped Avastin hold its place as Roche's third-best seller in the U.S. after Rituxan and HER2-positive breast cancer drug Herceptin.

With its sales growth already marginal, Avastin could be in for an even bigger hit if already-approved biosimilars hit the U.S. market anytime soon. In September 2017, Amgen and Allergan won an FDA nod for their Avastin biosimilar, Mvasi. Roche went on to sue the partners, and they've been embroiled in a lawsuit ever since—and Amgen still refuses to say when it might launch. Meanwhile, Pfizer's biosimilar is up for an FDA approval in June, and whether that will lead to a launch is up in the air. 

Roche CEO Severin Schwan has said he expects Avastin copies to roll out in the second half of this year. And that won't just hit the company's top line, either. Its bottom line is set to suffer, too. Schwan said last January that the mixture of coming patent expirations on Avastin, Herceptin and Rituxan and marketing investments in the company’s recent launches “puts a lot of pressure on the profitability.”

18. Avastin