A U.S. appeals court affirmed a 2005 ruling by a federal judge that upheld the validity of a disputed patent on Eli Lilly and Co.'s top-selling schizophrenia drug Zyprexa.
The U.S. Court of Appeals for the Federal Circuit said it had found no reversible error in the April 2005 ruling by U.S. District Court Judge Richard Young, which handed the company a major victory in its efforts to hold off generic competition.
The patent at issue in the case runs through April of 2011 and had been contested by Israel's Teva Pharmaceuticals and Indian drugmaker Dr. Reddy's Laboratories.
Representatives for Teva and Dr. Reddy's could not immediately reached for comment.
In 2005, Zyprexa made up 29 percent of Eli Lilly's $2.6 billion sales.
In the ruling issued on Tuesday, the appeals court rejected a series of arguments by the generic challengers aimed at overturning the earlier ruling.
The generic companies contended the Zyprexa patent was invalid because it was too similar to a previous patent held by Lilly, and that a form of the drug was in public use before Lilly received its patents.