Abstract| Volume 37, 101580, January 2020

The Use Natalizumab in Multiple Sclerosis Patients During Pregnancy is Safe and Prevents Disease Reactivation

      Data of the use of natalizumab during pregnancy is limited in Multiple Sclerosis (MS) patients. We aimed to assess the effectiveness and safety of natalizumab in MS during pregnancy.
      The cohort constituted 3 groups; patients continued natalizumab during pregnancy till 28th gestational week (group 1), patients discontinued natalizumab before pregnancy (group 2) and a control group included women who did not get pregnant (group 3). Relapses and MRI new T2/ gad-enhancing lesions during pregnancy and at one-year post delivery were compared.
      68 patients were identified. At baseline, there were no significant differences across the three groups in mean age (p = 0.07), mean age at onset (p = 0.44), mean disease duration (p = 0.21), annualized relapse rate (p = 0.27) and MRI measures (p = 0.25). The mean number of natalizumab infusions was 44 ± 26.05. During pregnancy, no relapses occurred in group 1 while four patients (28.6%) sustained relapses in group 2 (p = 0.03). At last follow-up visit, annual relapse rate was significantly higher in group 2 (0.75 ± 0.51), compared to groups 1 & 3 (0.14 ± 0.36 & 0.05 ± 0.22; p < 0.001) respectively. The proportion of patients with MRI activity was significantly higher in group 2 compared to groups 1 and 3 (50%, 7.1%, and 2.5%; p = 0.03). Abortion rate was not statistically significant between group 1 and 2 (p = 0.47) and no fetal malformation was observed.
      Patients who continued using natalizumab during pregnancy remained in remission. The use of natalizumab during pregnancy was safe.