WESTON, Mass. (AP) — Biogen Idec Inc. said today its profit more than doubled in the second quarter compared to a year ago, when it entered a partnership on a potential multiple sclerosis drug.

Biogen said its profit increased to $293.4 million, or $1.12 per share, from $142.9 million, or 49 cents per share. Revenue rose 11 percent to $1.21 billion from $1.09 billion.

Analysts on average expected a profit of $1.12 per share and $1.13 billion in revenue, according to Thomson Reuters.

The company said sales of the multiple sclerosis drug Tysabri rose 17 percent to $298 million. Biogen’s share of that revenue increased 17 percent to $219 million. Revenue from the cancer drug Rituxan grew 11 percent to $306 million, and sales of an older MS drug, Avonex, rose 6 percent to $628 million.

There were 52,700 patients on Tysabri at the end of June, up from 50,300 at the end of March.

Biogen sells Tysabri through a partnership with Elan Corp. PLC of Ireland, and it markets Rituxan with Roche AG’s Genentech division.

A year ago, Biogen paid $110 million to team up Acorda Therapeutics. The deal gave Biogen the overseas rights to the multiple sclerosis drug candidate Fampridine-SR, but reduced its quarterly profit by 32 cents per share.

Biogen raised its profit forecast for 2010, and now expects to earn at least $3.82 per share, or more than $4.70 per share excluding one-time costs and gains. In February the company forecast an annual profit of at least $3.71 per share, or at least $4.55 per share excluding one-time items.

Biogen still expects revenue to grow in the mid-single digits. Analysts expect a profit of $4.57 per share and revenue of $4.52 billion, up 3 percent from last year.

In premarket trading, shares of the company edged up 12 cents to $53.30.