To analyze the efficacy and safety of alemtuzumab in patients who switched from fingolimod.

At 12 months after the first course of Alemtuzumab (n=51), the annualized relapse rate (ARR) showed a reduction from 1.35±0.84 to 0.16±0.37 (p<0.001; RRR 88%) and mean expanded disability status scale (EDSS) score did not change. There was a reduction from 59% to 3% (n=29) in the proportion of patients who developed new gadolinium-enhancing lesions, and 86% of patients (n=37) did not present new T2 lesions on MRI.

At 24 months (n=24), the ARR decreased from 1.46±0.83 to 0.16±0.38 (p<0.01; RRR 89%) and mean EDSS score did not change. There was a reduction from 71% to 14% (n=14) in the proportion of patients who developed new gadolinium-enhancing lesions, and 95% of patients (n=17) did not present new T2 lesions on MRI.

Infections were detected in 55% of patients in the first year and in 52% in the second. Only 4 were categorized as serious: 3 urinary tract infections (UTI) and 1 Listeria infection. The most common infection type was UTI.

Thyroid disease was the only secondary autoimmune disorder observed (6% of patients in the first year, 21% in second) and only 1 case was serious (Grave´s disease).

In our experience in clinical practice, alemtuzumab has proved to be safe and effective in controlling disease activity in patients who switched from fingolimod.