The biotechnology company Biogen Idec reported that its fourth-quarter profit tumbled 21 percent, citing on Tuesday restructuring charges and rising expenses that outweighed the sales of key drugs.

The performance topped expectations on Wall Street and shares rose 3 percent.

.The Weston, Mass., company earned $240 million, or 99 cents per share, in the three months that ended Dec. 31. That compares with earnings of $305.6 million, or $1.06 per share, in the final quarter of 2009. Adjusted earnings were $1.42 per share. However, adjusted for the one-time costs, the company earned $1.42 per share.

That easily topped analysts surveyed by FactSet, who on average, earnings of $1.22 per share.

Revenue climbed 8 percent in the quarter to $1.22 billion, also edging out most analyst expectations.

Biogen incurred restructuring charges totaling $75 million in the quarter. The company said in November it was laying off 13 percent of its workforce, or 650 employees, in cost-cutting moves expected to yield about $300 million in annual savings.

The company also said it would close locations in Waltham and Wellesley, Mass., and San Diego.

Biogen's costs and expenses rose 16 percent in the quarter to $863.9 million, due in part to the restructuring charges and selling, general and administrative expenses that climbed 14 percent.

Biogen said quarterly revenue climbed as sales from the multiple sclerosis drugs Tysabri and Avonex rose 12 percent to $242 million and 10 percent to $654 million, respectively.

For 2010, the company earned $1 billion, or $3.94 per share, on $4.72 billion in revenue.

The company expects 2011 adjusted earnings per share to be above $5.70. Analysts expect, on average, earnings of $5.59 per share.

Shares of Biogen Idec Inc. climbed $2.08 to $67.55 at the start of trading.