To provide 2-year interim results for alemtuzumab in German real-world setting.

Alemtuzumab is approved in >70 countries for patients with highly active relapsing remitting multiple sclerosis (RRMS). The TREAT-MS study (Paul-Ehrlich-Institute registry: 281) investigates the real-world effectiveness and safety of alemtuzumab in RRMS patients in Germany.

TREAT-MS is an ongoing 5-year, noninterventional, multicenter study of alemtuzumab-treated patients. This interim analysis (cut-off 02 FEB 2021) included patients who had completed two years of follow-up. Data were analyzed exploratively according to the last previous therapy.

For this interim analysis 494 of 907 patients were considered. Hereof, 17.0% (n=84) were treatment-naïve and 83% received the following last previous therapy prior to alemtuzumab: fingolimod (28.5%, n=141), natalizumab (21.1%, n=104), basic injectables (glatiramer acetate or interferon-beta; 20.6%, n=102), or basic orals (dimethyl fumarate or teriflunomide; 12.8%, n=63). For 87.6% of patients no clinical disease progression (CDP) which could be confirmed over 6 months was documented. During a median observation period of 2.1 years after alemtuzumab initiation, 71.6% of all evaluable patients were relapse-free. However, this rate was lower in patients treated with fingolimod (61.2%). Percentage of patients relapse-free and without EDSS-based CDP was 55.9% for all evaluable and 48.2% of fingolimod-pretreated patients. For 28.4% of patients, at least one relapse was documented resulting in an annualized relapse rate of 0.2065 for all patients which was lowest for patients pretreated with basic injectables (0.1283) and highest for fingolimod-pretreated patients (0.3100). Adverse events related to alemtuzumab were documented for 60.3% of patients. Most frequently reported adverse events related to alemtuzumab included headache, rash, and nasopharyngitis.

These interim results indicate that alemtuzumab shows good real-world effectiveness and safety across patient subgroups with different pretreatment history but less pronounced effects after fingolimod pretreatment.