Abstract
BACKGROUND: This meta-analysis aimed to assess the treatment effects of immunotherapies in subgroups of adults with clinically isolated syndrome or relapsing forms of multiple sclerosis (MS) and the effect of potential treatment effect modifiers (TEMs). METHODS: Phase 2 and 3 RCTs with a placebo comparator were analyzed. Risk of bias was assessed. Random-effects meta-analyses were conducted to summarize treatment effects within subgroups and differences in treatment effects between subgroups. RESULTS: Thirty-one studies were included. Age < 40 years was the strongest TEM for relapse rate across DMTs with a ratio of rate ratios (RRR) of 1.44 (95% CI 1.09-1.90; 7 studies). Disability progression was influenced by age (ratio of hazard ratios, RHR 1.59, 95% CI 1.11-2.29; 4 studies). Dichotomizing patients based on EDSS cut-offs (EDSS 2.0 and 3.0) also showed a significantly higher benefit for those less disabled for relapse rate (RRR 1.35, CI 1.03-1.76; 8 studies). Sex, baseline MRI parameters, previous immunotherapy, and clinical presentation showed no effect in this meta-analysis. CONCLUSION: Age < 40 is a robust TEM for a lower relapse rate as well as less disability progression across six MS immunotherapies. Additionally, a lower baseline EDSS was predictive of the relapse rate.