Post-natalizumab clinical and radiological findings in a cohort of multiple sclerosis patients: 12-month follow-up.

There is an urgent need to identify the best strategies to prevent the loss of natalizumab (N) beneficial effects after its suspension. The objective is to evaluate the clinical and radiological disease activity and to test the efficacy of immunomodulatory/immunosuppressive drugs (IT) after N suspension. Clinical and radiological data from 54 patients 2 years before treatment (pre-N), during treatment (on-N) and after interruption, during 1-year follow-up (post-N) were retrospectively collected. Annualized relapse rate (ARR), expanded disability status scale (EDSS), presence of new T2 lesions and Gd+ (gadolinium enhancing) T1 lesions were evaluated. Pre-N ARR at 1 year was 1.74 while post-N ARR was 0.94 (p = 0.0053). We observed that post-N disease activity never raised over pre-N levels, neither post-N ARR nor post-N EDSS. In patients retreated with N after suspension, post-N ARR was significantly lower than pre-N ARR (p = 0.017), but not in patients treated with other IT or in patients not treated with any disease modifying drugs (DMD). The mean time of freedom from new T2 lesions and new Gd+ lesions was lower in post-N period compared to on-N (T2 lesions p = 0.0000, Gd+ lesions p = 0.0000). In conclusion, a "rebound" pattern was not identified in our cohort, though the disease activity rapidly returned after N, regardless of the treatment used.