Biogen to reinstate monthly PML updates

BIOGEN IDEC – the Boston-based pharmaceutical firm which co-owns the Tysabri multiple sclerosis drug with Athlone-based Elan – is set to re-instate monthly updates of outbreaks of PML, the rare brain disease which is a potential side effect of using Tysabri, after announcing four further cases of the condition.

The four new instances of PML were developed by Tysabri users in the US during November and bring the total number of outbreaks amongst users of the treatment to 28. Biogen recently ceased updating on new PML cases on its website, but is likely to release data for December before the end of this month.

The risk of contracting PML led to Tysabri being re-labelled after it was initially pulled from the market in 2005 for a year, following the first outbreaks of the disease amongst users. Since then four Tysabri users who have contracted PML have died as a result.