In an effort to beef up its oncology offerings, Amgen Inc. has agreed to purchase a Maryland-based biotech company that focuses on cancer cures for $1.16 billion while reported rising revenue, but declining income for the fourth quarter in 2011.

The Thousand Oaks biotech giant reported $3.97 billion in revenue during the fourth quarter, a 3 percent increase compared to the same period in 2010. Net income fell 8.6 percent to $934 million in the fourth quarter, or $1.08 per share.

Profit was hurt by one-time charges, the company said, including expenses related to acquisitions and stock options. Accounting for those charges, Amgen said it earned $1.04 billion, or $1.21 per share.

“We exited 2011 with good momentum and the outlook for 2012 is even stronger,” retiring CEO Kevin Sharer said in a statement. “Our acquisition of Micromet...further builds our innovative oncology therapeutics pipeline and capabilities.”

With the acquisition of Micromet, announced on Jan. 26, Amgen gains a drug in clinical development for treating leukemia as well as for non-Hodgkin’s lymphoma.

The purchase was unanimously approved by both companies’ boards of directors and is expected to close in the first quarter, the two companies said.

Amgen’s earnings, reported after the market closed, beat analysts’ expectations for revenue and just missed it for earnings per share. Analysts polled by Yahoo! Finance expected fourth quarter revenue of $3.91 billion and adjusted earnings per share of $1.22.

Amgen’s stock remained unchanged in after-hours trading. The stock closed down 1.63 percent at $68.08.

Andrew Khouri