After many false starts investors will be hoping that the end of a long road is in sight after the scientific committee of the European Medicines Agency recommended on Friday that Elan's Tysabri multiple sclerosis treatment should be allowed to return to market. It's never plain sailing with Elan, however.

The shares closed unchanged in Dublin on Friday after reaching a high of 12.35.

The muted response was due to the fact that the panel said the drug should only be approved for use by patients with the most severe form of MS, or in those that haven't been helped by other MS treatments.

When the Food and Drug Administration advisory panel recently recommended the return of Tysabri to the US market, it suggested that the drug could be given to patients displaying initial symptoms, and that it should be prescribed as a so-called 'front-line' treatment that can be used before any other drugs have been tried.