Biogen Idec ( BIIB) beat profit expectations Tuesday, becoming the third big biotech to deliver better-than-expected third-quarter product sales.Shares closed at $47.49 on Monday. The company said Tuesday that it earned $207 million, or 70 cents a share, in the third quarter, versus a year ago profit of $119 million, or 41 cents a share. On an adjusted basis, Biogen earned 98 cents a share, up from 58 cents in the year-ago quarter. Revenue increased 38% to $1.09 billion. Profit results trounced the expectations of analysts, who on average were expecting 89 cents a share on $1 billion in revenue, according to Thomson Reuters. Biogen followed its peers Genentech ( DNA) and Gilead ( GILD), which reported earnings last week, in presenting better-than-expected sales of its key products. Biogen said sales of Rituxan, a drug partnered with Genentech, rose to $299 million, beating the consensus targets for $276 million. The company garnered $573 million in worldwide sales from multiple sclerosis drug Avonex. Multiple sclerosis drug Tysabri, for which Biogen partners with Elan ( ELN), beat expectations with $237 million in sales. Biogen will record $171 million of those Tysabri sales. Analysts had predicted $528 million in sales from Avonex and $220 million from Tysabri, with $164 million of that going to Biogen. In the third quarter, Biogen reported the first two confirmed cases of brain infection progressive multifocal leukoencephalopathy -- a known risk of the drug -- since its relaunch in 2005. Subsequently, the Food and Drug Administration expanded the label to include the risk of progressive PML with Tysabri when it's used alone.