8. Restasis

allergan irvine
Allergan executives expect Restasis exclusivity through March 31. (Allergan)

Company: Allergan
2018 U.S. sales: $1.2 billion
Disease: Dry eye
Competition expected: After March 31

Restasis may well be the first—and last—time a drugmaker tries to use a patent licensing deal with a Native American tribe to protect a drug from generic competition. Allergan struck its notorious licensing pact way back in September 2017, earning the company plenty of scorn, and market watchers quickly said it gave the industry a black eye at a time when drug pricing was making regular headlines.

But even as the strategy has faced scrutiny, and Allergan continues to defend it, Allergan has suffered a series of legal defeats. Mylan, for one, prevailed in a federal court case in getting Restasis patents invalidated.

But Allergan's losses in court haven't led to copycat competition for Restasis. Generics makers simply haven't been able to secure FDA nods for their versions. That could change soon, though, as Bernstein analyst Ronny Gal wrote Monday that Mylan has an upcoming FDA decision date, and that his team hears an approval is "likely."

Even after predicting generics would launch last year, Allergan still has an exclusive lock on the market, and the drug managed to pull in $1.2 billion in 2018 sales as the copies failed to arrive. Now, executives say they expect to hang onto their Restasis monopoly at least through the end of March. 

RELATED: Court rejects Allergan's tribal licensing strategy, striking another blow to its Restasis generics defense

Teva, Mylan, Amneal and many other generic drugmakers want to take a piece of the brand's sales, according to a lawsuit filed by four grocery chains last year. The retailers sued Allergan for an "unlawful scheme" to protect Restasis, saying Allergan made "material misrepresentations" to win follow-up patents as its original IP shields were expiring. If not for those misrepresentations and Allergan's conduct afterward, generics would have rolled out as early as May 2014, the plaintiffs claim.

"But for the drain on resources, confusion and administrative delays resulting from Allergan’s improper Orange Book listing, citizen petitions and/or patent suits, some or all of these generic competitors would have been approved and on the market," the retailers said in the filing.

8. Restasis