12. Remodulin

United Therapeutics expects competition to its top med, Remodulin, this year. (Wikipedia user Farragutful)

Company: United Therapeutics
2017 global sales: $671 million
Disease: Pulmonary arterial hypertension
Patent expiration: June 26

For a smaller pharma company like United Therapeutics, losing patent protection on a big drug is especially painful. Remodulin, approved in 2002, loses exclusivity this summer, meaning the company will soon face off against cheap competition to its biggest top-line contributor.

The drug pulled in $671 million globally last year, United Therapeutics reported, or about 39% of the company’s total sales. Under a 2015 patent settlement, Novartis’ Sandoz can launch its version of the PAH injection on June 26. Sandoz is the only company to boast a tentatively approved generic, according to [email protected]

Teva, Par and Dr. Reddy's could launch their own generics in December, United Therapeutics reported in an annual filing.

Meanwhile, United has won approval for Orenitram, a follow-up to Remodulin that pulled in $185 million last year.

Remodulin isn’t the only hit expected for United Therapeutics this year, either. Adcirca, a PAH med that racked up $420 million in 2017, is slated to face generic rivals in May, according to the drugmaker.

United Therapeutics derives a full 89% of its revenue from U.S. sales, according to its annual securities filing. In reporting 2017 results, the company didn’t break out its U.S. sales for Remodulin.

12. Remodulin