AstraZeneca ($AZN) has gotten mixed results in a lawsuit agreement as it continues to try to hold generics at bay in the U.S. for its blockbuster stomach drug Nexium. It said today that it has reached a legal settlement in its patent fight with Hanmi Pharmaceutical and its marketing partner Amneal Pharmaceuticals. Under the "consent judgement," those two agreed that two of AstraZeneca's patents are valid, but it said that Hanmi's product didn't violate the patent. AstraZeneca will appeal that finding, but if Hanmi gets FDA approval while the appeal is pending, it can launch its drug at-risk. That would mean if AstraZeneca wins its appeal, Hanmi would face double damages. But by then the hurt to AstraZeneca could be pretty significant. In these cases, drug buyers often stock up on the generic, and it can take a long time for the branded drug to recover. Nexium is one of the few big drugs AstraZeneca has going for it as the company works to rebuild its pipeline. Having that revenue stream impaired is no small matter. In its first quarter of 2013, the drugmaker reported that total sales dropped 12%, while core earnings fell 21%. Its key drug, Crestor, already faces generics in Canada, while generics of Nexium are available in some markets outside the U.S. Release | More