The European Commission has renewed its authorisation for the multiple sclerosis treatment Tysabri for another five years.
Pharmaceutical company Elan and its partner Biogen said the commission had also backed an addition to the list of risk factors which must now accompany the treatment.
The new language in the summary of product characteristics states that patients who are anti-JCV antibody positive are at an increased risk of developing progressive multifocal leukoencephalopathy (PML) compared to patients who are anti-JCV antibody negative.
Elan said the addition of the warning would help give confidence to doctors and patients by giving guidance on the potential risk of developing PML, a brain infection.
There have been cases of PML in patients taking Tysabri, but the European regulators have previously said that the treatment's benefits outweigh the risks for patients with MS.
