Biogen Idec has posted first-quarter results which reveal a 2.8% rise in net profits, boosted by continuing strong sales of its multiple sclerosis blockbuster Tysabri.

Net income came in at $302.7 million, while revenues increased 7.4% to $1.29 billion. Sales were again driven by Tysabri (natalizumab), partnered with Ireland’s Elan Corp, which brought in $285.5 million to Biogen's coffers, up 13.6%.

As for the company’s older MS drug Avonex (interferon beta-1a), sales climbed 3% to $661.6 million. Chief executive George Scangos noted that orders of the drug in January "were impacted by what we believe to be isolated events" concerning distribution, but "sales rebounded quickly and we believe the underlying Avonex business is solid".

The rheumatoid arthritis and cancer drug Rituxan (rituximab), partnered with Roche, brought in $285 million, up 11%. Recently-launched Fampyra, a prolonged-release tablet formulation of fampridine to improve walking in adults with MS licensed from Acorda Therapeutics, contributed just over $15 million, while sales of the psoriasis treatment Fumaderm (fumaric acid) rose 6.3% to $13.3 million.

Dr Scangos noted that the quarter saw Biogen file for marketing approval for the oral MS candidate BG-12 (dimethyl fumarate) in both the USA and Europe and continue to "ramp up R&D activity as we executed on six Phase III programmes and advanced our early-stage pipeline". This year, the firm expects late-stage data from its long-lasting factor VIII and factor IX programs for haemophilia and for the amyotrophic lateral sclerosis treatment dexpramipexole.

Biogen also announced that it expects to repurchase an additional $500 million in shares this year.