(Reuters) - A U.S. appeals court found the patent on Novo Nordisk's Prandin diabetes drug in combination with metformin to be invalid, paving the way for introduction of a generic version of the medicine, the Danish drugmaker said on Tuesday.
In a 2-1 ruling, the U.S. Court of Appeals affirmed a district court ruling handed down in 2011, the company said.
Novo said it still believes the patent to be valid and was reviewing the ruling.
Prandin, known chemically as repaglinide, and its combination with the commonly prescribed type 2 diabetes drug metformin, sold as PrandiMet, had sales of about $200 million in 2012 for Novo, one of the world's top manufacturers of diabetes treatments.
(Reporting by Bill Berkrot; Editing by Steve Orlofsky)