Natalizumab discontinuation and disease restart in pregnancy: a case series

Background - The humanized monoclonal alpha4-integrin antibody Natalizumab (NTZ) (Tysabri (c), Biogen Idec, Cambridge, MA, USA) has shown to be effective in multiple sclerosis (MS) therapy; however, the interruption of the drug has been related to a disease restart. This risk has to be carefully considered in case of accidental or desired pregnancies. Aim of the study - To report the risk of disease restart in patients who interrupted NTZ because of pregnancy and discuss the implication of NTZ choice in female childbearing patients with MS. Methods - Clinical histories and MRI images of four pregnant women with MS who interrupted NTZ. Results - Despite pregnancy is usually related with disease stability, the cases presented here showed an abrupt increase of disability with high number of MRI lesions, some of them with a mass effect. Conclusions - We recommend that female patients on childbearing age must be informed before starting NTZ treatment of the risk of a return of disease activity when the drug is discontinued. The risk occurs even during pregnancy a condition that is considered as protective for women with MS.