Shares in AstraZeneca PLC jumped 6 percent Wednesday after the drug maker won a key patent battle in the United States over Seroquel, its anti-psychotic drug and second-best seller.

The decision by a U.S. court to award a summary judgment in AstraZeneca's favor avoids the need for a full trial and means that generic copies of Seroquel, which raked in $4 billion in sales last year, will not be launched any time soon.

"We are pleased with the court's decision to uphold our valid intellectual property," AstraZeneca chief executive officer David Brennan said in a statement.

Shares rose 6.1 percent to 2,260 pence ($44.88) in London. Shares jumped 3.4 percent to $44.89 in premarket trade on the New York Stock Exchange.

Teva Pharmaceutical Industries Ltd., the world's biggest generic drug maker, said it plans to appeal the judgment by the U.S. District Court for the District of New Jersey.

A summary judgment of "No Inequitable Conduct" is traditionally difficult to win because it requires the company to prove the intent of the patent holder.