A US Federal Court has upheld Eli Lilly's patents for Evista, after Israel's Teva Pharmaceuticals attempted to market a generic version of the osteoporosis treatment.
A district judge for Indianapolis ruled that Teva is barred from selling the drug in the US before Eli Lilly's patents expire in March 2014.
Teva, which had already received US Food and Drug Administration approval for its generic version of the drug, alleged that the patents were nothing more than obvious variations of commonly known combinations.
The company planned to begin marketing the drug earlier this year but was blocked by the judge in April, pending the decision.
Teva plans to appeal the ruling, the company said in a statement.
The drug, branded as raloxifene, generated $1.08bn in global sales in 2008.