Nov 12 (Reuters) - Drugmaker Merck & Co Inc said the U.S. Court of Appeals for the Federal Circuit invalidated four patents related to the antibiotic, Cubicin, that expire in 2019 and 2020.
The drugmaker had sued Hospira, now a unit of Pfizer Inc , in March 2012, saying Hospira's application to sell a generic version of the antibiotic infringed five patents.
Thursday's decision will keep a Cubicin generic out of the market only until June 2016. The court invalidated four of Merck's patents that would have protected the drug's market share up to 2020.
New Jersey-based Merck said it would review the court's decision and consider steps including seeking a further review by the Federal Circuit or Supreme Court.
Merck obtained rights to Cubicin through its $8.4-billion acquisition of Cubist Pharmaceuticals in December 2014.
The antibiotic, which was approved by the U.S. Food and Drug Administration in 2003, generated sales of about $325 million in the quarter ended Sept 30.
Merck's shares were little changed at $53.36 in afternoon trading on the New York Stock Exchange.
(Reporting by Rosmi Shaji in Bengaluru; Editing by Anil D'Silva)