Elan and Biogen hit by EU Tysabri questions

The European medicines Agency's (EMEA) Committee for Medicinal Products for Human Use, (CHMP) Committee has started a review of the benefits and risks of Tysabri (natalizumab), in view of reports of 23 cases of progressive multifocal leukoencephalopathy (PML) worldwide since Tysabri has been on the market.

This review is initiated to discuss any additional measures necessary to ensure the safe use of Tysabri and how to balance the risks to the patients against the benefits of the treatment. Tysabri is indicated for patients suffering from highly active relapsing remitting multiple sclerosis with high disease activity despite treatment with a beta-interferon and for patients with rapidly evolving severe relapsing-remitting multiple sclerosis.

The news caused the two companies which market the drug, the USA's Biogen Idec and Ireland's Elan, to plunge 5.4% $44.69 and 20.5% to 3.42 euros, respectively, on October 23. Tysabri was Elan's key revenue and cash generator and contributed to 65-70 per cent of its annual revenue, said Sam Farthing of Merrion Capital Group in Dublin. There was a danger doctors would prescribe the drug to fewer patients and for shorter treatment periods to limit risk, Mr Farthing said.