Observational Study of Switching from Natalizumab to Immunomodulatory Drugs

Objective: To determine the effect of disease-modifying drugs (DMDs) on disease activity rebound in patients discontinuing natalizumab (NTZ).

Methods: Twenty-one patients with relapsing-remitting multiple sclerosis (RRMS) treated with NTZ for ≥1 year and who switched to DMDs (glatiramer acetate [GA] or interferon) were followed up for 12 months in clinical practice. Clinical outcomes after NTZ cessation were assessed every 3 months for 1 year and MRI was performed at 12 months.

Results: Twelve months after switching from NTZ to DMDs, there were no significant differences in the annualized relapse rate (ARR) compared to the days that NTZ was used (0.3 vs. 0.1; p = 0.083); and the ARR never reached similar values to those prior to NTZ use (1.61; p < 0.001). The percentage of relapse-free patients after switching from NTZ was 71.4%. These patients did not have lower disease activity before NTZ compared with those with clinical relapses (1.3 vs. 1.7; p = 0.302), but they had lower Expanded Disability Status Scale scores (3.4 vs. 5.7; p = 0.001). DMDs had beneficial effects on MRI parameters, as 10 of 16 patients (62.5%) presented no evidence of radiological activity 12 months after NTZ discontinuation.

Conclusions: Patients with RRMS and moderate disability who discontinued NTZ for safety reasons may benefit from the DMDs GA and interferon with no known risk for progressive multifocal leukoencephalopathy.