A district court has ruled that a patent protecting AstraZeneca's (NYSE:AZN) billion-dollar...

A district court has ruled that a patent protecting AstraZeneca's (NYSE:AZN) billion-dollar Pulmicort Repsules asthma treatment is invalid, opening the way for Actavis (NASDAQ:ACT) to launch a generic version. The ruling won't affect AstraZeneca's 2013 revenue guidance, but it will hurt royalties that the company receives from Teva's (NYSE:TEVA) version of Pulmicort. It's a further blow for AstraZeneca as it restructures amidst a patent cliff. (PR)