Real-world transition from uncontrolled disease to stability: Three-year Pre-post natalizumab comparison in relapsing...

Natalizumab is a highly effective therapy for relapsing multiple sclerosis (MS), yet few real-world studies have directly compared disease activity before and after treatment initiation within the same patients.

To evaluate the real-world impact of natalizumab on relapse activity, disability, and MRI activity by comparing disease outcomes during the three years before and after treatment initiation.

We retrospectively analyzed 246 patients who initiated natalizumab at a single centre. After excluding patients without baseline data (n = 38) or with insufficient follow-up or incomplete MRI data (n = 77), 131 patients were included in the final analysis. Annualized relapse rate (ARR), Expanded Disability Status Scale (EDSS), and MRI activity were compared between the 36-month pre-treatment and 36-month on-treatment periods.

Natalizumab treatment was associated with a marked reduction in relapse activity. Mean ARR decreased from 0.69 in the pre-treatment period to 0.04 during the on-treatment period, and the proportion of patients with relapses declined from 88.5% to 8.4%. Disability remained overall stable during follow-up, with no significant difference between EDSS three years before treatment and EDSS three years after treatment. MRI activity decreased from 74.8% in the pre-treatment period to 9.2% during the on-treatment period, and 84.0% of patients achieved no evidence of disease activity (NEDA-3). Pregnancy-related observations were limited to a small descriptive subgroup.

Over three years, natalizumab was associated with substantial suppression of relapse activity, stable disability, and reduced MRI activity compared with the pre-treatment period.