Is natalizumab a safe treatment for patients with multiple sclerosis in the COVID-19 pandemic? Data from the first year of the pandemic

BACKGROUND: Patients with MS have increased risk of infections, especially those with highly active treatments. We studied the safety of natalizumab in patients with MS during the COVID-19 pandemic. METHODS: Demographic features, time on natalizumab, dose interval and COVID-19 symptoms were evaluated in a prospective study of patients with MS receiving natalizumab during the pandemic. RT-PCR COVID-19 tests from nasopharyngeal samples were performed before natalizumab treatment. RESULTS: We analyzed 69 patients: 71% women, mean age 43 years. Mean treatment duration was 68 months (range: 2–141). In 32% of patients, natalizumab regimen was changed from every 4 to every 6 weeks to decrease number of hospital visits. From March to April 2020, 5 patients had COVID-19, 4 showed mild symptoms and 1 a multi-lobar pneumonia. On May 2020, we started COVID-19 screening before natalizumab infusion. From May 2020 to March 2021, tests were performed on 553 nasopharyngeal swabs. Fourteen patients had a positive result and natalizumab was stopped; tests were repeated 1–2 weeks later, with negative results, and natalizumab was restarted. In summary: 19 patients had COVID-19, 10 asymptomatic, 7 mild symptoms, 2 pneumonia (1 of whom hospitalized without mechanical ventilation). There were no statistically significant differences in age (mean±standard deviation, 35.7±11.5 vs 43.4±7.8 years; p=0.158), dose interval (5.33 vs 5.32 weeks; p=0.962) or treatment duration (5.8 vs 5.6 years; p=0.298) between patients with and without COVID-19. CONCLUSION: Natalizumab treatment in MS seems to be safe during the pandemic. Most patients were asymptomatic, and no patient required mechanical ventilation.