9. Pristiq

Pfizer

Company: Pfizer
Disease: Major depressive disorder
2016 U.S. sales: $578 million
U.S. patent expiration date: March 2017

Pfizer's antidepressant Pristiq hit the market in 2008, just as its predecessor, Effexor, was nearing the end of its branded life. As a "new-and-improved" version of Effexor's active ingredient, venlafaxine, Pristiq was first developed by Wyeth, before it merged into Pfizer in 2009 to create the drug giant it is today.

Wyeth—and then Pfizer—of course hoped that Pristiq (desvenlafaxine) would replace Effexor in its antidepressant lineup. And that was a big hope: Effexor brought in about $2.7 billion in 2009, its last full year of branded sales. But it's tough for a new formula to compete against generics, and Pristiq didn't launch as quickly as hoped. Its U.S. sales peaked at $737 million in 2014, slid to $715 million in 2015 and ended 2016 with $578 million.

Now, Pfizer is set to face generic competition for Pristiq in March, according to a document put out by pharmacy benefit manager OptumRx. That makes it a Peri-LOE product, in Pfizer parlance, and that soon-to-lose-exclusivity drug is not only facing U.S. patent protection, but its patent shield in various countries around the globe, Pfizer said.

In an email to FiercePharma, a Pfizer representative confirmed the March date for Pristiq's loss of exclusivity in the U.S.

Drugs@FDA lists Mylan, Lupin, Actavis and Sandoz among the companies with approvals for a generic version. According to Optum, generic makers Alembic, Lupin, Mylan, and Sandoz will share exclusivity on the market when they launch their copycats.

The med carries a black-box warning covering the risk of suicidal thoughts and behaviors. Back in 2012, Pfizer had to pay $67.5 million to settle a class action suit with shareholders of Wyeth who claimed they weren't warned about Pristiq's safety problems. Pfizer bought Wyeth for $68 billion in 2009.

Pristiq's original FDA nod was contingent on some post-marketing studies, one of which Pristiq flunked.

9. Pristiq