Safety and efficacy of autologous hematopoietic stem-cell transplantation following natalizumab discontinuation in aggressive multiple sclerosis

Background and purpose Natalizumab (NTZ) is a highly effective treatment for relapsing-remitting multiple sclerosis (MS), but its withdrawal is often followed by disease reactivation or rebound, even if other disease-modifying treatments (DMTs) are administered. In this study, for the first time, the safety and efficacy of autologous hematopoietic stem-cell transplantation (aHSCT) performed following NTZ discontinuation were retrospectively compared with conventional DMTs. Methods Patients with relapsing-remitting MS treated with NTZ who discontinued the drug after at least six administrations and with at least 6 months of follow-up were included. Patients underwent aHSCT after a minimum of 6 months following NTZ withdrawal, receiving meanwhile cyclophosphamide or corticosteroids, or other DMTs approved for MS (control group) after an adequate wash-out period. Both hematological and neurological follow-up were assessed according to standard policies. Results A total of 52 patients were included, 11 who received aHSCT and 41 who received DMTs. Baseline clinical and demographic characteristics were similar between the two groups. No fatality or life-threatening complications, including progressive multifocal leukoencephalopathy, were observed. At 3 years following NTZ discontinuation, no evidence of disease activity was reported in 54.5% of the patients in the aHSCT group compared with 11.5% of those in the DMT group (P = 0.0212). Disease reactivation in the patients with aHSCT was observed only during wash-out/bridging therapy and 100% of the cases were free from disease activity after aHSCT. Conclusions These data suggest that an aggressive therapy should be established after NTZ with the shortest possible wash-out period. aHSCT after 6 months from NTZ withdrawal appears to be safe.