Natalizumab plus interferon beta-1a reduces lesion formation in relapsing multiple sclerosis

The SENTINEL study showed that the addition of natalizumab improved outcomes for patients with relapsing multiple sclerosis (MS) who had experienced disease activity while receiving interferon beta-1a (IFNβ-1a) alone. Previously unreported secondary and tertiary magnetic resonance imaging (MRI) measures are presented here. Patients received natalizumab 300 mg (n = 589) or placebo (n = 582) intravenously every 4 weeks plus IFNβ-1a 30 µg intramuscularly once weekly. Annual MRI scans allowed comparison of a range of MRI end points versus baseline. Over 2 years, 67% of patients receiving natalizumab plus IFNβ-1a remained free of new or enlarging T2-lesions compared with 30% of patients receiving IFNβ-1a alone. The mean change from baseline in T2 lesion volume over 2 years decreased in patients receiving natalizumab plus IFNβ-1a and increased in those receiving IFNβ-1a alone (–277.5 mm3 versus 525.6 mm3; p < 0.001). Compared with IFNβ-1a alone, add-on natalizumab therapy resulted in a smaller increase in mean T1-hypointense lesion volume after 2 years (1821.3 mm3 versus 2210.5 mm3; p < 0.001), a smaller mean number of new T1-hypointense lesions over 2 years (2.3 versus 4.1; p < 0.001), and a slower rate of brain atrophy during the second year of therapy (–0.31% versus –0.40%; p = 0.020). Natalizumab add-on therapy reduced gadolinium-enhancing, T1-hypointense, and T2 MRI lesion activity and slowed brain atrophy progression in patients with relapsing MS who experienced disease activity despite treatment with IFNβ-1a alone.