Rituximab suppresses disease activity after natalizumab withdrawal: an exploratory study

Background Natalizumab is highly effective in reducing multiple sclerosis disease activity; however it carries a risk of progressive multifocal leukoencephalopathy, that represents the main reason of drug discontinuation. After natalizumab withdrawal, reactivation of disease is soon observed and, until now, it is not known which treatment strategy should be followed after natalizumab discontinuation. Aim of this study is to evaluate rituximab efficacy in controlling disease activity after natalizumab withdrawal. Case Presentation Ten relapsing-remitting multiple sclerosis patients treated with natalizumab stopped it for the high risk of progressive multifocal leukoencephalopathy and started rituximab after a wash out period of two months; Second cycle of rituximab was planned in case of CD19+ cells increase and/or disease reactivation; brain MRI was performed before starting rituximab and then at six and twelve months after it. Conclusions All the patients showed disease stability during the wash out period. Radiological stability was observed at 6 and at 12 months in all the patients; during the follow up two patients had exacerbation of sensitive symptoms without evidence of brain MRI activity. This study gives evidence of rituximab efficacy in abolishing disease reactivation after natalizumab withdrawal.