Safety, efficacy, and tolerability of alemtuzumab in pediatric patients with active relapsing-remitting multiple sclerosis: The LemKids study.

Background: Limited licensed medications are available for multiple sclerosis (MS) in pediatric patients.

Objective: To evaluate the efficacy, safety, and tolerability of alemtuzumab in pediatric patients with relapsing-remitting multiple sclerosis (RRMS) and disease activity on prior disease-modifying therapies (DMTs).

Methods: LemKids was a multicenter, multinational, single-arm, open-label, switch (from ongoing DMT to alemtuzumab treatment) study in pediatric RRMS patients (aged 10-<18 years), with disease activity on DMT. The primary endpoint was a comparison of the number of new/enlarging T2 lesions on the magnetic resonance imaging of the brain between the prior-DMT period and alemtuzumab treatment.

Results: This study was prematurely terminated due to low enrollment and an European Medicines Agency Article-20 pharmacovigilance review of alemtuzumab in adult RRMS. Of 46 screened patients, 16 were enrolled; 12 completed prior-DMT treatment period; 11 received alemtuzumab of whom 7 completed treatment. Patients on alemtuzumab developed fewer new/enlarging T2 lesions compared with prior-DMT (7 vs 178, relative risk (95% confidence interval): 0.04 (0.01-0.14)). No significant pharmacodynamic changes or safety concerns were noted in this limited dataset.

Conclusion: Alemtuzumab treatment was associated with a low number of new/enlarging T2 lesions in pediatric patients with RRMS and was safe and well tolerated in seven patients during infusion and the initial 4 months.