Pfizer Sues Teva over Generic Version of Sildenafil

Pfizer has sued Teva Pharmaceuticals to prevent a generic version of Pfizer's anti-impotence drug sildenafil (Viagra) from entering the market until at least 2019.

The lawsuit, filed last week in the U.S. District Court for the Eastern District of Virginia, notes that Pfizer originally patented sildenafil in 2002 and that, in 2007, Teva received FDA approval to sell a generic version of sildenafil for treatment of of erectile dysfunction.

The suit contends that Pfizer has two patents on sildenafil -- one that expires in 2012 and another that expires in 2019.

The first covers the composition of drug itself, the second covers its use for erectile dysfunction.

The suit alleges that immediately upon expiration of Pfizer's first patent on March 27, 2012, "Teva intends to market [its generic version of sildenafil] ... for treatment of erectile dysfunction."

Doing so would be an infringement of Pfizer's second patent, and would "substantially and irreparably" harm Pfizer, according to the suit.

The suit seeks to bar Teva from selling generic sildenafil until the expiration of the second patent in 2019. It also seeks reimbursement for Pfizer's legal expenses.

A spokeswoman for Teva said the company had no comment on the suit. Pfizer did not respond to a request for comment.

The ED drug has been a big seller for Pfizer, bringing in worldwide revenues in 2009 of $1.9 billion (down by by 2% from 2008).

Israel-based Teva, the world's largest generic drugmaker, recently won a bidding war against Pfizer to take over another large generic drug firm, Germany's Ratiopharm Group.