Shares in AstraZeneca jumped nearly 10% after the Anglo-Swedish drugs giant received a favourable US ruling in its battle to keep control of the patents to its best-selling cholesterol-lowering drug Crestor.The ruling means that cheaper, generic versions of Astra's blockbuster drug can not enter the US market until 2016.Shares in the drug market are currently up 9.16% at 3,217.00p after hitting highs of 3,262.00p earlier this morning.Judge Joseph Farnan of the US District Court of Delaware found that the substance patent protecting Crestor is "valid and enforceable," ending a three-year battle with nine generic drugs manufacturers.Judge Farnan said the generic drugmakers had not "established, by clear and convincing evidence, that the 314 patent is invalid as an improper reissue" of an older patent. Astra's chief executive officer David Brennan said the court's decision "reaffirms the strength of the intellectual property protecting Crestor." A number of brokers upgraded their ratings and target prices for the stock after the announcement.Panmure Gordon has doffed its hat to AstraZeneca's legal eagles. "The company's impressive record in intellectual property litigation continues with a win on Crestor to accompany wins on Prilosec , Pulmicort respules , Seroquel and to an extent Nexium as well," writes Panmure analyst Savvas Neophytou.