Elan Corp of Ireland has announced a widening of its losses for the fourth quarter, though revenues climbed 31.2% to $218.3 million, driven by the take-up of its multiple sclerosis treatment Tysabri.

Net loss increased to $83.5 million, or $0.18 per share, up from $26.5 million, or $0.06 per share, in the like, year-earlier period, while the loss for the full year, $405.0 million, rose 51.5%. The increase was due to costs relating to generic competition for the antibiotic Maxipime (cefepime), restructuring at its US operations and early repayment of debt.

As for the revenue rise, Elan noted that global sales of Tysabri (natalizumab). Global sales of the drug, which is marketed in tandem with Biogen Idec, reached $129.1 million, up from $30.2 million in the like, year-earlier period, with Elan reported Tysabri revenues for the fourth quarter of $90.6 million. Tysabri only returned to the market in July 2006 after being pulled off on safety concerns in February 2005, and its reintroduction came with restrictions to monitor patients for symptoms of the rare brain disease progressive multifocal leukoencephalopathy.

Some 21,000 patients were being treated with Tysabri by the end of the year, noted Elan chief financial officer Shane Cooke. He added that “we remain confident that we will achieve our target of having 100,000 patients on Tysabri therapy by the end of 2010”, claiming that group revenues should top the $1 billion mark in 2008.

As for its other products, generic competition meant that Maxipime suffered a 66% decline in revenues to $15.8 million, while Azactam (aztreonam), another antibiotic, rose 10% to $23.4 million. Elan said that Azactam is expected to be negatively impacted by generic competition, although no copycat version has been approved yet. Manufacturing revenues and royalties increased 8% to $72.8 million.