WASHINGTON, Dec 19 (Reuters) - The drug company AstraZeneca PLC lost a bid on Thursday to defend its widely used heartburn drug Nexium when an appeals court ruled that a new drug from Hanmi Pharmaceuticals did not infringe on Nexium patents.
The U.S. Court of Appeals for the Federal Circuit upheld a lower court's ruling that Hanmi did not infringe on AstraZeneca's patent since the South Korean company uses different salts in making its products.
The Federal Circuit issued an injunction against the Hanmi drug in August, but lifted it in September, AstraZeneca said earlier this week. Hanmi has won FDA approval for the drug, AstraZeneca said.
Britain's second-biggest drugmaker had accused Hanmi of patent infringement by developing the rival drug, which is not chemically identical to Nexium and would not be automatically substitutable for Nexium at pharmacies, AstraZeneca said.
Nexium is set to lose U.S. patent protection in 2014.
AstraZeneca said earlier this week that the outcome of the decision would have no impact on the company's full-year 2013 financial guidance.
AstraZeneca shares closed up 1.1 percent in London on Thursday. Its U.S.-listed shares were down 0.4 percent at $58.61 on the New York Stock Exchange in Thursday afternoon trading.