Toprol-XL patents found invalid
Executive Summary
The U.S. Court of Appeals for the Federal Circuit upheld a district court ruling that AstraZeneca's Toprol-XL (metoprolol succinate) patents are invalid and unenforceable based on double patenting. However, the court vacated the lower court's finding of inequitable conduct by AstraZeneca. The court concluded that there are questions of fact involving AstraZeneca's failure to disclose a dispute over inventorship to the U.S. Patent and Trademark Office and sent the issue back to the U.S. District Court for the Eastern District of Missouri for review. AstraZeneca filed suit against KV Pharmaceutical, Andrx and Eon Labs after they filed ANDAs to market generic versions of the hypertension treatment. Sandoz and KV subsequently filed citizen petitions to block each other from marketing formulations of the drug (1"The Pink Sheet" July 9, 2007, p. 26)...