Amgen Inc. posted higher-than-expected third quarter earnings, thanks in large part to a hefty one-time government purchase of Neupogen (filgrastim). That contract, combined with anticipated revenues from recently acquired Onyx Pharmaceuticals Inc., prompted the Thousand Oaks, Calif.-based biotech to bump up its revenue guidance for the year but fell short of distracting investors and analysts away from long-term plans for growth.