Treatments of paediatric multiple sclerosis: Efficacy and tolerance in a longitudinal follow-up study

Aim: To compare the efficacy and safety of newer and/or second-line disease-modifying treatments (DMTs) with interferon beta-1a. Method: This observational retrospective study included patients younger than 18 years old in the French KIDBIOSEP cohort who had a diagnosis of relapsing multiple sclerosis between 2008 and 2019 and received at least one DMT. Primary outcome was the annualized relapse rate (ARR). Secondary outcomes were the risk of new T2 or gadolinium-enhanced lesions on brain MRI. Results: Among 78 patients enrolled, 50 were exposed to interferon and 76 to newer DMTs. Mean ARR went from 1.65 during pre-treatment period to 0.45 with interferon (p < 0.001). Newer DMTs reduced ARR compared to interferon: fingolimod 0.27 (p = 0.013), teriflunomide 0.25 (p = 0.225), dimethyl-fumarate 0.14 (p = 0.045), natalizumab 0.03 (p = 0.007). Risk of new lesions on MRI was reduced with interferon compared to pretreatment period; it decreased even more with newer DMTs for T2 lesions. Regarding risk of new gadoliniumenhanced lesions, the added value of new treatments compared to interferon was less obvious, except for natalizumab (p = 0.031). Conclusion: In this real-world setting, newer DMTs showed better efficacy than interferon beta-1a on ARR and risk of new T2 lesions, with a good safety profile. Natalizumab tend to emerge as the most effective treatment.