10. Zytiga

Johnson & Johnson's Zytiga could face generics in October, according to an analyst. (Wikipedia)

Company: Johnson & Johnson
2017 U.S. sales: $1.228 billion
Disease: Prostate cancer
Generics expected: October 2018

Johnson & Johnson might reject the idea that its key prostate cancer therapy Zytiga will face 2018 generic competition, but at least one analyst hasn’t bought the drugmaker’s arguments.

Credit Suisse analyst Vamil Divan, M.D., expects Zytiga to come up against generic competition this year, contrary to what J&J executives maintained on a recent conference call.

The company suffered a setback at the U.S. Patent Trial and Appeal Board (PTAB) in January, when it lost an inter partes review (IPR) challenge brought by Argentum Pharmaceuticals against the blockbuster’s 2027 patent, easing—if not clearing—a path toward 2018 copies.

Still, during the drugmaker’s fourth-quarter conference call, CFO Dominic Caruso said J&J does “not expect to see generic competition for Zytiga in 2018.”

RELATED: J&J's blockbuster Zytiga falls to patent challenge, boosting threat of 2018 generics

Divan thinks otherwise. At the time of the IPR decision, he wrote that he and his team didn’t “expect the final patent remaining on Zytiga to hold up to challenge, and we have been anticipating a generic entry following the expiration of a 30-month stay in October 2018."

An official patent challenge from a generics maker triggers that automatic delay under the Hatch-Waxman Act.

Divan added that his team has not heard “a reason to believe otherwise” from discussions with the company. Johnson & Johnson has said it will ask for a rehearing before the PTAB or appeal the board's decision to “vigorously” defend its patent.

Despite the near-term threat in the U.S., Zytiga's overall revenue haul is somewhat insulated from generic erosion. As Divan noted, more than half of Zytiga’s sales come from outside of the U.S., and Credit Suisse predicts Zytiga revenues will hold steady this year at $2.4 billion globally. After that, expect a long slide to $46 million by 2026.

10. Zytiga