By Samuel Howard

Law360, New York (October 20, 2009, 6:01 PM ET) -- Armed with a brand-new patent for its Suvaxyn piglet vaccine, Wyeth has unleashed another infringement action against rivals Schering-Plough Corp. and Boehringer Ingelheim GmbH.

The complaint, filed Tuesday in the U.S. District Court for the District of Delaware, alleges Schering-Plough’s Intervet Inc. and Boehringer’s Vetmedica Inc. each manufactures vaccines to prevent piglet weight loss disease and other porcine circovirus-associated diseases, termed PCVAD, that infringe Wyeth’s patent.

Wyeth, which Pfizer Inc. acquired last week, filed suit moments after the U.S. Patent and Trademark Office issued U.S. Patent...