Shares in AstraZeneca PLC jumped 6 percent on 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 the drug, which made $4 billion in sales last year, will not be launched in the near future.