Fingolimod to treat severe multiple sclerosis after natalizumab-associated progressive multifocal leukoencephalopathy: a valid option?

We report two cases of multiple sclerosis (MS) patients with natalizumab-associated progressive multifocal leukoencephalopathy. Severe MS relapses occurred between four and five months after natalizumab discontinuation. After failure of immunomodulatory treatment, both patients were treated with fingolimod. The outcome was positive on clinical and MRI disease activity, without worsening of the progressive multifocal leukoencephalopathy. These observations suggest that using fingolimod for severe multiple sclerosis after natalizumab-associated progressive multifocal leukoencephalopathy may be an option, under close clinical and radiological monitoring.