Exposure to DMTs reduces disability progression

Recent real-world findings of the Italian MS Registry E-MUSIC suggest the existence of different impactful periods of intervention [1]. There was an apparent higher impact for paediatric onset (POMS ≤18 years) and adult onset MS (AOMS 18-49 years), and a lower -but still detectable- impact in late onset MS (LOMS ≥50 years). So, age is a critical factor in the evaluation of benefit-risk ratio in the decision-making process regarding treatment initiation and outcome.

Age at onset is one of the factors that can predict evolution of MS or risk of disability accumulation over time. In clinic- and population-based studies, the onset of the progressive phase is seemingly age-dependent [1-3]. The earlier the onset of the disease, the younger the age at which various landmarks are reached. The effectiveness of disease-modifying treatments (DMTs) on reducing disability worsening decreases with age.

A real-world analysis from the Early MS Italian cohort (E-MUSIC), presented by Dr Mattia Fonderico (University of Florence, Italy), evaluated how the traditional prognostic predictors vary in 3 subgroups of relapsing MS patients defined by age at onset: POMS (n=646), i.e. age ≤18 years; AOMS (n=8,473), i.e. age 18-49 years; and LOMS (n=448), i.e. age ≥50 years [4]. DMTs reduced the risk of CDP in all the cohorts. This appeared to be related to the cumulative exposure to DMTs in a dose-dependent manner, with progressive risk reduction in different quartiles of exposure. The risk ratios for disability progression at 3 months in non-exposed versus exposed >62% of the time in the 3 age groups were: POMS 8.1; AOMS 6.7; and LOMS 7.5 (P<0.0001) [4]. Results were consistent for CDP at 12 months in POMS and AOMS. Relapses, considered as time-dependent covariate, were a risk factor for 3- and 12- month CDP in POMS (HR 2.5; P=0.002) and AOMS (HR 1.3; P<0.0001) but not in LOMS (HR 0.98) [4].

The current, real-world data from the Italian MS Registry suggests that DMTs can reduce the risk of irreversible disability progression. In different quartiles of exposure, risk reduction was related to the cumulative time spent under therapy. In all 3 cohorts, untreated patients were at higher risk of disability progression, independent of their age of onset [4].

1. Kantarci OH. Continuum (Minneap Minn). 2019;25:636-654.
2. Scalfari A, et al. Neurology. 2011;77:1246-52.
3. Tedeholm H, et al. J Neurol. 2015;262:1148-63.
4. Fonderico M, et al. ECTRIMS 2019, abstract 303.

Posted on 8 November 201922 March 2021