Biogen Idec has posted a strong set of second-quarter results which reveal a 34% rise in net profits, boosted by its multiple sclerosis blockbusters Avonex and Tysabri.

Net income came in at $386.8 million, while revenues increased 18% to $1.42 billion. Sales were driven by the company’s older MS drug Avonex (interferon beta-1a), up 16% to $762.0 million.

The rise was due in part to strong uptake of the Avonex Pen (the first intramuscular autoinjector for chronic use designed to enhance the self-injection process) and Avostartgrip titration dosing kit in both the USA and Europe.

Sales of Tysabri (natalizumab), partnered with Ireland’s Elan Corp, were flat and contributed $280.4 million to Biogen's coffers. However the firm noted that globa sales were up 2% to $395 million and as of the end of June, some 69,100 patients were on Tysabri therapy worldwide.

The rheumatoid arthritis and cancer drug Rituxan (rituximab), partnered with Roche, brought in $285 million, up 31%, though the total was reduced by $50 million to reflect its share of damages and interest that might be awarded in relation to a dispute between Roche's Genentech unit and Sanofi subsidiary Hoechst.

Fampyra, a prolonged-release tablet formulation of fampridine to improve walking in adults with MS licensed from Acorda Therapeutics, contributed $19.7 million, while sales of the psoriasis treatment Fumaderm (fumaric acid) dipped 2.9% to $14.6 million.

Chief executive George Scangos said that "we had a very productive quarter, delivering both revenue and earnings growth". He added that "we have a busy nine months ahead of us" preparing for the potential launch of the MS pill BG-12 (dimethyl fumarate) and "four pivotal trial data readouts" - for long-lasting blood factors VIII and IX for haemophilia, dexpramipexole for amyotrophic lateral sclerosis and PEGylated interferon beta-1a for MS.