Delayed initiation of disease modifying therapy increases relapse frequency and motor disability in pediatric onset multiple sclerosis.

OBJECTIVE

To evaluate association between time to initiation of disease modifying treatment (DMT) and outcomes in pediatric-onset Multiple Sclerosis (POMS).

METHODS

A retrospective analysis of children with POMS from two tertiary referral pediatric Neuroimmunology clinics. Outcome measures comprised annualized relapse rate (ARR), MRI lesion burden (T1, T2-FLAIR, and post-GAD contrast sequences), EDSS, and 25-ft walk duration at the latest follow-up visit. Univariate and multivariate analysis using linear and logistic regression models were used to assess associations between patient characteristics and outcomes.

RESULTS

In total, 68 patients were reviewed. More than half of patients were female (62 %) and 32 (47 %) were Hispanic/LatinX. Median age at diagnosis was 14.2 years (IQR: 11.0-16.5), and median duration from diagnosis to the latest follow-up was 2.5 years (IQR: 1.6-4.6). Sensory (29.4 %), brainstem (23.5 %), and pyramidal (19.1 %) symptoms were most common. Interferon beta (32.4 %), dimethyl fumarate (27.9 %) and rituximab (26.5 %) were the most frequently used first-line DMT. Patients had a median ARR of 0.5 (IQR: 0.08-0.84), and EDSS score of 1.0 (IQR: 0.0-2.0) at the most recent follow-up. Delayed DMT initiation correlated with higher ARR (R = 0.38, p = 0.0016) and longer 25-ft walk duration (R = 0.34, p = 0.0077). In multivariate analysis, delayed DMT remained a significant predictor of higher ARR (p = 0.002) and longer 25-ft walk duration (p = 0.047). Delayed DMT initiation and use of low/moderate efficacy DMT predicted GAD enhancing lesions at the latest follow-up (p = 0.004 and 0.019 respectively).

CONCLUSION

Delayed DMT initiation in POMS is linked to unfavorable outcomes, including higher ARR and longer 25-ft walk duration.