Therapeutic Outcome of Alemtuzumab in Korean Patients with Multiple Sclerosis: 2-Year Follow-Up

BACKGROUND AND PURPOSE: Alemtuzumab has shown high efficacy in clinical trials that primarily involved Western multiple sclerosis (MS) patients. To evaluate the therapeutic outcome of alemtuzumab in Korean patients with MS. METHODS: This study enrolled 23 consecutive patients who were treated with alemtuzumab from 2015 to 2018. Efficacy was evaluated using the annualized relapse rate (ARR), Expanded Disability Status Scale (EDSS), and radiological activity. No evidence of disease activity (NEDA) was defined as no clinical relapse, no worsening of the EDSS score, and no radiological activity. The safety profiles were also assessed. RESULTS: The mean age was 36 years and 16 of the patients were female. Seventeen and 12 of 23 patients were followed up for 1 year and 2 years, respectively. The ARR was markedly reduced from 1.52 during the 1-year period preceding alemtuzumab administration to 0.21 after initiating alemtuzumab (p<0.001). During the first and second years after initiating alemtuzumab, EDSS worsening was observed in 3 (18%) and 0 (0%) patients, respectively, and radiological activity was exhibited in 9 (53%) and 4 (33%). NEDA was observed in 6 (35%) patients during the first year and in 8 (67%) patients during the second year. Intriguingly, one patient experienced 2 severe clinical exacerbations, which occurred at 10 months after the first and 10 months after the second infusion of alemtuzumab. Nineteen of the 23 patients exhibited infusion-associated reactions and 3 patients exhibited herpes zoster infection. Thyroid dysfunction occurred in two patients at 18 and 20 months after initiating alemtuzumab. CONCLUSIONS: Consistent with observations in Western populations, alemtuzumab therapy in Korean MS patients led to marked reductions of disease activity without unexpected safety issues.