AstraZeneca UK Ltd. has launched a patent infringement suit against Watson Pharmaceuticals Inc. in its most recent attempt to block generic-drug makers from producing copycat versions of its blockbuster cholesterol drug Crestor®. AstraZeneca's complaint, lodged Tuesday in the U.S. District Court for the District of Delaware, claims that Watson's new drug application for approval to market rosuvastatin zinc tablets infringes U.S. Patent Number RE37,314. Crestor®, a prescription drug belonging to a group of medicines that are used to treat high cholesterol, has been prescribed to more than 21 million patients worldwide and generated $4.5 billion in sales for AstraZeneca in 2009, according to the company. AstraZeneca is represented by Finnegan.