IRISH drug company Elan has received the go-ahead from the European Commission to include information on its Tysabri multiple-sclerosis drug, warning patients and doctors that having specific virus antibodies is a risk factor in developing a potentially deadly brain disease.
The anticipated approval means that doctors and MS patients taking the Tysabri drug can more accurately weight up the likelihood of developing progressive multifocal leukoencephalopathy (PML), a disease that has so far killed 23 people using the drug.
People who carry antibodies to the so-called JC virus are more prone to developing PML. About 60,000 people around the world use Tysabri and there have been 124 confirmed cases of PML to date among patients who have taken the drug. Only one case has been confirmed in either Ireland or the UK, in a Sligo-based pharmacologist who is now in a paraplegic state.
Inclusion of the information regarding the JC virus on the Tysabri label should give a boost to sales, Elan and its drug partner Biogen Idec believe, as potential and existing users will be better qualified to make decisions about using the drug.
Elan and Biogen have also developed a test to allow people to quickly determine whether or not they carry the JC Virus antibodies. About 55pc of MS patients carry the JC virus.
The new Tysabri label should help raise annual sales of the drug to $2.7bn (€1.9bn) by 2016, according to Olav Zilian, an analyst with Helvea in Geneva. About $1.7bn of that would accrue to Elan.
Elan has also received permission from the European Commission to market Tysabri in the EU for an additional five years.
Shares in Elan jumped in Dublin during early trading but fell back later in the day to close down 1.1pc at €7.26.