U.S. federal judges upheld patents on major drugs marketed by Bristol-Myers Squibb and Eli Lilly and in rulings that would keep generic versions out of the United States for several years.

U.S. District Judge Mary Cooper in Trenton, New Jersey, upheld the validity of a U.S. patent through April 2015 for the antipsychotic drug Abilify.

That ruling was a victory for Bristol-Myers and its Japanese partner Otsuka Pharmaceutical and a defeat for Teva Pharmaceutical Industries, Novartis' Sandoz unit and other makers of generic drugs.

Meanwhile, U.S. District Judge Gregory Sleet in Wilmington, Del., upheld the validity of Lilly's patent for Alimta, which is used to treat mesothelioma, a form of lung cancer commonly caused by asbestos exposure.

Lilly had also sued Teva over the patent, which it said expires in July 2016. Sleet issued his ruling from the bench after a one-week non-jury trial, court records show.

Lawyers for defendants in both cases did not immediately return calls seeking comment. It is common for rulings on drug patents to be appealed.

Abilify is Bristol-Myers second biggest-selling drug. It accounted for $1.86 billion of sales in the first nine months of 2010, or 13% of the New York-based company's total. Abilify is used to treat schizophrenia, bipolar disorder and depression. Alimta is Lilly's third biggest-selling drug, accounting for $1.64 billion of sales in the same nine-month period, or 10% of the Indianapolis-based company's total.

Otsuka is privately held and based in Tokyo.

Seamus Fernandez, an analyst at Leerink Swann & Co, had written on Monday that investors expected Bristol-Myers to win, and that allowing generic versions of Abilify would have cut Bristol-Myers' earnings per share by 40 cents through 2014.