THOUSAND OAKS, California (AP) — Amgen Inc. said Thursday that its fourth-quarter profit fell 8.5 percent as its expenses for taxes and producing and selling drugs rose faster than its revenue.

The world's largest biotech company said its net income was $934 million, or $1.08 per share, down from $1.02 billion, also $1.08 per share, a year earlier.

Excluding one-time items, it said it earned $1.04 billion, or $1.21 per share, down 6 percent from $1.1 billion, or $1.17 per share.

Revenue was $3.97 billion, up 3 percent from $3.84 billion in 2010's fourth quarter.

Analysts on average expected earnings per share of $1.22 and sales of $3.92 billion, according to FactSet.

"We exited 2011 with good momentum, and the outlook for 2012 is even stronger," CEO Kevin Sharer, who is stepping down in May, said in a prepared statement.

Amgen said this expects to earn $5.90 to $6.15 per share for 2012, excluding one-time items, and take in revenue of about $16.3 billion. Analysts were expecting $5.97 per share in adjusted earnings and $16.06 billion in revenue for the year.

Earlier Thursday, the maker of biologic drugs for cancer and blood disorders said it plans to buy cancer therapy developer Micromet Inc. for $1.16 billion in cash to boost its oncology pipeline. Founded in Germany and based in Rockville, Maryland, Micromet is developing an experimental antibody-based drug, blinatumomab. It's currently in mid-stage testing to treat leukemia and in clinical development for the treatment of non-Hodgkin lymphoma.

The purchase is Amgen's largest since it bought BioVex Group last year in a deal worth up to $1 billion, including milestone payments.

For the full year, Amgen reported net income of $3.68 billion, or $4.04 per share, down 20 percent from $4.63 billion, or $4.79 per share in 2010. Adjusted income was $4.86 billion, or $5.33 per share, down 3 percent from $5.02 billion, or $5.21 per share. Revenue was up 3 percent to $15.58 billion, from $15.05 billion.

Analysts were expecting adjusted income of $5.33 per share on average and revenue of $15.51 billion.

Amgen shares were unchanged following the after-hours report. They ended regular trading Thursday down $1.13, or 1.6 percent, at $68.08.