Trends in the Epidemiology and Treatment of Pediatric-Onset Multiple Sclerosis in Alberta, Canada

BACKGROUND: Fingolimod became the first disease-modifying therapy approved by Health Canada for pediatric multiple sclerosis in 2018, but the impact of that approval on treatment patterns in Canada is unknown. The aim of this study was to describe trends in the epidemiology and treatment of pediatric-onset multiple sclerosis in Alberta, Canada. METHODS: This study entailed a retrospective review of administrative health databases using 2 case definitions of multiple sclerosis. Those <19 years of age at a date of diagnosis between January 1, 2011, and December 31, 2020, were included. Incidence and prevalence estimates were calculated and stratified by sex and age cohort. Pharmacy dispenses of disease-modifying therapies were identified. RESULTS: 106 children met one or both case definitions. In 2020, the age-standardized incidence using the 2 case definitions was 0.47 and 0.57 per 100 000, and the age-standardized prevalence was 2.84 and 3.41 per 100 000, respectively. Seventy-nine incident cases were identified, 38 (48%) of whom were dispensed a disease-modifying therapy prior to age 19 years. Injectables accounted for all initial pediatric disease-modifying therapy dispenses prior to 2019, whereas in 2019-2020 injectables accounted for only 3 of 15 (20%) initial dispenses, and instead B-cell therapies were the most common initial disease-modifying therapy (6 of 15, 40%). In 2020, B-cell therapies were the most common disease-modifying therapy dispensed overall (9 of 22 dispenses, 41%) followed by fingolimod (6 of 22, 27%). CONCLUSION: The treatment of children with multiple sclerosis in Alberta has evolved, with a rapid shift in 2019 away from injectables to newer agents, although B-cell therapies—not fingolimod—are now most commonly dispensed.