Thousand Oaks-based Amgen Inc. posted a profit if $1 billion, or $0.82 per share on revenues of $3.22 billion in the first quarter, compared with earnings of $854 million, or $0.657 per share, on revenues of $2.83 billion during the same period last year. The earnings for the period include a charge of $0.09 related to the acquisition of Immunex and Tularik, stock option expenses and miscellaneous other costs. Revenues were pumped up by strong sales of the company’s anemia and arthritis drugs.