3. Lyrica

After more than a decade on the market, Lyrica will face competition later this year unless Pfizer wins an FDA extension. (Image: Wikipedia user Acdx)

2017 U.S. sales: $3.46 billion
Disease: Nerve and muscle pain
Patent expiration: Dec. 30

Pfizer’s Lyrica has had quite a run, but after generating many billions in sales, its exclusive life is coming to an end in the U.S. Lyrica’s patent protections expire in December unless the drugmaker can get a pediatric exclusivity extension that would stretch its branded sales into next year.

First approved in 2004, Lyrica was Pfizer’s top drug last year—trailing only pneumococcal vaccine Prevnar 13—among the company’s bestselling products. The med generated $3.46 billion in the U.S. last year.

In recent months, Lyrica has been among a group of drugs to get price hikes at the New York drugmaker, including one in January as highlighted by Wells Fargo analyst David Maris. As its patent expiration nears, Pfizer has been spending heavily on DTC advertising as well, grabbing the No. 2 spot ranked by 2017 spending, behind AbbVie and its immunology megablockbuster Humira. For the year, Pfizer spent $216 million promoting its drug on television screens.

RELATED: With a year left before generics hit, Pfizer nabs FDA approval for new-and-improved Lyrica

A who’s who of generic drugmakers have tentative approvals for Lyrica knockoffs at the FDA, including Mylan, Teva, and Novartis’ Sandoz.

As the patent expiration nears, Pfizer recently won FDA approval for an extended release version that could attract some patients. Lyrica CR is approved to treat pain caused by shingles or diabetic peripheral neuropathy, but not fibromyalgia like the original. It’s a once-daily tablet, compared to the original formulations that are dosed two to three times per day.

Lyrica’s impending patent loss closely follows that of another legendary Pfizer drug, Viagra, which came under generic attack in December. Analysts expect that med and competitor Cialis from Eli Lilly to quickly lose sales as cheap generics grab share. Cialis loses exclusivity later this year and has already suffered the impact of cheap competition to Viagra.

3. Lyrica