Safety of natalizumab reinfusion during active Sars-Cov-2 infection in patients with multiple sclerosis

Introduction: Extending natalizumab (NTZ) dosing in patients with Multiple Sclerosis (MS) may increase the risk of disease reactivation. Nevertheless, evidence is lacking on the safety of reinfusion during active Sars-Cov-2 infection in patients needing retreatment. Aims and Objective: To describe the clinical outcome of patients with MS (PwMS) receiving NTZ redosing during active Sars- Cov-2 infection. Methods: 14 NTZ treated PwMS (mean age 39 years, females 11, median number of NTZ infusions 47) from 6 Italian MS centers with diagnosis of Sars-Cov2 infection confirmed by positive RT-PCR nasopharyngeal swab were retrospectively included.The main variables analyzed were baseline characteristics, outcome of infection after reinfusion, hospitalization, time to negative swab and occurrence of neurological complications. Results: All patients had symptomatic COVID-19 (13 mild, 1 moderate). None required respiratory support or hospitalization. At the time of NTZ reinfusion (median interval 52 days from the previous infusion), 14/14 had a positive molecular test performed within a median time of 3 days (0-11) and 4/14 were symptomatic. After infusion, none complained of worsening of COVID-19 symptoms or reported neurological complications. Median time to negative swab was 14,5 days (2-36) from infusion and 34,5 days (12-62) from first positive swab. Conclusions: In response to primary concerns about potential worsening of COVID-19 symptoms, due to the neuro and gastrointestinal tropism of Sars-Cov-2, our data support the safety of NTZ redosing in patients with active infection;therefore, in this condition, NTZ should not be interrupted/delayed, in order to minimize the risk of relapses.