Summarize the demographic/clinical characteristics and efficacy outcomes of individuals with pediatric-onset multiple sclerosis (POMS) who were treated with Avonex or Plegridy

IM interferon beta-1a (Avonex®) and peginterferon beta-1a (Plegridy®) have been shown to be effective in placebo-controlled randomized trials and real-world evidence for adults with relapsing forms of multiple sclerosis (MS). However, there are limited data in pediatric patients with MS that are receiving these therapies.

Data from patients treated at the United States Network of Pediatric MS Centers (NPMSC) are entered into the Pediatric MS and Demyelinating Diseases (PeMSDD) database. The population studied includes individuals who have used IM interferon beta-1a (Avonex®) or SC peginterferon beta-1a (Plegridy®) for any length of time prior to age 18 and excludes those with primary progressive diagnosis as last MS diagnosis. Outcomes assessed when use became sustained (three months) include annualized relapse rate (ARR), time to first relapse, and time to MRI activity.

Overall, the NPMSC registry included 254 patients who have been treated by Avonex (n = 220), Plegridy (n= 32) or both treatments (n = 2) before the age of 18. An estimated 66.3% of patients on sustained Avonex and 72.9% of patients on sustained Plegridy were relapse-free the first year. ARR was 0.45 on Avonex and 0.33 for Plegridy. For Avonex-treated patients, 67.9% and 82.8% had no new T2 lesions or gadolinium lesions at 1 year, respectively. For Plegridy-treated patients, 52.5% and 77.9% had no new T2/gadolinium lesions at 1 year, respectively. An estimated 76.8% and 67.9% of patients would not have EDSS progression within 1 year while on Avonex and Plegridy, respectively.

The data from this registry are consistent with previously reported clinical and MRI effects of approved interferon beta therapies more traditionally utilized in adult populations.

Biogen provided funding for this study.