Objective: To study the clinical course, the rate of progression and the results of the disease modifying treatment (DMT) in pediatric-onset multiple sclerosis (POMS) patients in the Voronezh region.

Methods: The clinical characteristics of the course of relapsing-remitting multiple sclerosis (MS) were analyzed among 51 POMS patients and 51 patients with the adult-onset MS (AOMS). The clinical course was assessed based on the Expanded Disability Status Scale (EDSS) score, the average annual frequency of exacerbations and the rate of disease progression before and during DMT.

Results: There were no statistically significant differences in EDSS scores 11 years after the onset of MS between the groups: POMS patients achieved moderate disability by the age of 25, and AOMS patients showed stabilization of their condition during DMT by the age of 36. During changing first-line drugs in patients with POMS, there was again an increase in disability with the transition of 25% of patients to the group with secondary progression of MS on average after 8 years of DMT.

Conclusions: The onset of the disease in children and adolescents leads to a significant decrease in their quality of life and the deterioration of all activities throughout their lives. To prevent the progression of the disease it seems appropriate to transfer patients with POMS immediately to second-line DMT when signs of a suboptimal response to first line DMT appear, and in the case of a rapidly progressive course to start therapy with second-line drugs.