Summary Box: Biogen Idec earnings

KEY RESULTS: The company's 11 percent profit boost was driven by sales of the multiple sclerosis drugs Avonex and Tysabri. Revenue rose 28 percent, with Avonex sales up 14 percent and Tysabri sales more than tripling.

OUTLOOK: Biogen boosted its full-year profit and revenue outlook, expecting a continued upward drive in multiple sclerosis drug sales.

ANALYST TAKE: Wall Street applauded the results, which allayed some fears that Avonex sales might slide as Tysabri continues to gain ground in the market. Still, several analysts maintained a cautious stance on Tysabri as the possibility for new cases of a nerve disorder in patients remains. The drug was pulled from the market in 2005 after three patients developed a rare nerve disorder, but was allowed back on the market under a restricted distribution program.