European regulators have started an “urgent review” of Biogen and Abbvie’s multiple sclerosis therapy Zinbryta following a stream of cases of serious inflammatory brain disorders in patients taking the drug.

Seven incidences of such disorders, including encephalitis and meningoencephalitis, were reported in Germany plus one in Spain, the European Medicines Agency confirmed.

The firms said they intend to voluntarily withdraw the medicine’s marketing authorisations around the globe, as well as suspend ongoing clinical studies with Zinbryta (daclizumab).

“Given the nature and complexity of adverse events being reported, characterizing the evolving benefit/risk profile of Zinbryta will not be possible going forward given the limited number of patients being treated. Therefore, Biogen and AbbVie believe it is in the best interest of patients to voluntarily withdraw worldwide marketing authorisations for Zinbryta,” the firms said in a statement.

The regulator is advising doctors not to start new patients on the therapy and also switch those already taking it to an alternative as soon as possible.

Zinbryta, a human monoclonal antibody that modulates interleukin-2 signalling to reduce central nervous system pathology, and the occurrence of relapses and disability progression, was cleared in Europe in July last year.

To date more than 8,000 patients have been treated with Zinbryta around the globe, with the majority of patients in Europe treated in Germany.