A federal judge upheld the validity of a U.S. patent for the blockbuster antipsychotic Abilify, handing a legal victory to the drug's co-marketers, Otsuka Pharmaceutical Co. and Bristol-Myers Squibb Co. (BMY).

Several generic-drug makers including Novartis AG (NVS) and Teva Pharmaceutical Industries Ltd. (TEVA) had challenged the patent's validity in an attempt to sell cheaper copycat versions before patent protection expires in 2015 (including a six-month extension granted for studying the drug in children).

Otsuka filed patent-infringement lawsuits against the companies to block the early launch of any generic versions of the drug, which is approved to treat schizophrenia, bipolar disorder and depression.

In a decision issued Monday, Judge Mary Cooper in federal court in New Jersey ruled that the patent was "not invalid," and barred the generics manufacturers from selling copies before the patent expired.

Bristol-Myers co-markets Abilify with Otsuka in the U.S. Bristol reported $1.9 billion in Abilify sales for the first nine months of 2010.

A nonjury trial was held in the case in August. A mandatory, 30-month delay in U.S. regulatory approval of any generic version of Abilify was due to expire Monday, under federal laws governing generic drugs and patent litigation.

Bristol-Myers shares rose 40 cents, or 1.5%, to $26.42 in recent trading.

-Peter Loftus, Dow Jones Newswires; +1-215-656-8289; peter.loftus@dowjones.com