Figure 3 Measurement of disease activity

Longitudinal analysis of the annual relapse rate was assessed in 21 patients with multiple sclerosis (MS) for the 12-month period prior to enrollment into the AFFIRM and SENTINEL trials (MS pre Nat), for the trial period of the AFFIRM and SENTINEL trials (MS Nat), and for the 14-month period after cessation of natalizumab (MS Nat 14 months) (A). In addition, neurologic disability assessed by the Expanded Disability Status Scale (EDSS) was recorded in 17 patients prior to enrollment into the AFFIRM and SENTINEL trial (MS pre Nat), at the time of cessation of natalizumab therapy (MS Nat), and 14 months after cessation of natalizumab (MS Nat 14 months) (B). There was a significant decrease in the annual relapse rate in patients with MS on natalizumab during the AFFIRM and SENTINEL trials compared to the pretrial period (A). There was also a significant decrease in the annual relapse rate in the 14-month period after cessation of therapy compared to the pretrial period (A). In contrast, there was no significant difference in the annual relapse rate between patients on natalizumab during the AFFIRM and SENTINEL trials and during the 14-month period after cessation of natalizumab therapy (A). There was no significant difference with regard to neurologic disability as assessed by the EDSS scale among the three time points in this patient cohort (B). The number of new gadolinium-enhancing (Gd+) lesions on T1-weighted MRI (C), the total lesion volume on T2-weighted (D) and FLAIR-weighted images (E) was assessed while patients received natalizumab, and 14 months after discontinuation of therapy. There was no significant difference with regard to Gd+ lesions on T1-weighted images (C) and the total lesion volume on T2-weighted (D) and FLAIR weighted images (E).