Biogen Idec today reported a higher first-quarter profit as sales of its new Tecfidera multiple sclerosis drug extended a run of eclipsing Wall Street sales expectations.

The US biotechnology company also raised its full-year forecasts.

Tecfidera racked up sales of $506m for the quarter, easily topping analysts' expectations of about $440m and the previous quarter's sales of $398m.

The oral medicine, which was approved in the US in March 2013, had been on track to become the drug to reach $1 billion in sales in the shortest time. 

But that pharmaceutical industry record was shattered earlier this week, when Gildead Sciences said its Sovaldi hepatitis C treatment had logged more than $2 billion in sales in its first full quarter on the market.

Based on the strong performance of its MS drugs, Biogen raised its full-year forecast and now expects revenue growth of 26-28%, up from a prior range of 22-25%.

The company said it expected 2014 earnings, excluding items, of $11.35 to $11.45 per share, compared with a prior outlook of $11 to $11.20.

Analysts on average are looking for a profit of $11.32 per share, according to Thomson Reuters I/B/E/S.

The company reported net income of $479.9m, or $2.02 per share for the quarter, compared with $426.7m, or $1.79 per share, a year earlier.

Excluding special items, Biogen said it earned $2.47 per share, missing the analysts' average estimate of $2.55. But the company said its earnings were reduced by about 35 cents a share due to a $118m expense from a collaboration with Japan's Eisai on development of an Alzheimer's disease treatment.