Net income for pharmaceutical manufacturer Amgen increased a sluggish 2 percent for the first quarter when compared to a year ago. The Thousand Oaks-based company saw both its domestic and international sales slip by 3 percent and 1 percent respectively. Taking changes in the exchange rate into consideration, however, international sales increased by 10 percent for the first quarter when compared to last year. The company still expects to reach its stated earnings guidance for the year, said Kevin Sharer, chairman and CEO. “We continue to be encouraged by the lasting effects of our cost management efforts,” Sharer added. For the quarter ending March 31, Amgen reported a net income of $1.14 billion, or $1.04 per diluted share, on revenues of $3.6 billion. For the same period in 2007, the company reported net income of $1.1 billion, or $0.94 per diluted share, on revenues of $3.7 billion. Shares of Amgen closed down at $42.40.