Pfizer Wins Viagra Patent Trial Court Rules Teva Infringes Viagra Use Patent Expiring in 2019 http://www.marketwatch.com/story/pfizer-wins-viagra-patent-trial-2011-08-15 NEW YORK, Aug 15, 2011 (BUSINESS WIRE) -- Pfizer Inc. announced today that it has prevailed in its patent infringement action against Teva Pharmaceuticals USA, Inc. in the United States District Court for the Eastern District of Virginia.