Boston—While multiple sclerosis (MS) is usually diagnosed in young adulthood, about 3% to 5% of cases begin in childhood or adolescence, usually with a relapsing–remitting pattern, according to a new study.

The article in the New England Journal of Medicine describes a very different course for pediatric MS, with relapse rates—often severe—during the first 6 years of the disease more than twice as high as among adult patients.

In addition, progression is slower in children than in adults: Patients with pediatric-onset MS take about a decade years longer than patients with adult-onset MS to reach the secondary progression phase and irreversible disability, but they still do so at a chronological age of approximately 10 years younger than those with adult-onset disease, according to background information in the study.

Despite that, there are few randomized trials in MS patients younger than age 18 years. Massachusetts General Hospital–led researchers sought to remedy that by comparing fingolimod with interferon beta-1a treatment in that cohort.

In a phase III trial by the PARADIGMS Study Group, investigators randomly assigned patients 10 to 17 years of age, mean age 15.3 years, with relapsing MS in a 1:1 ratio to receive oral fingolimod at a dose of 0.5 mg per day—0.25 mg per day for patients with a body weight of 40 kg or less—or intramuscular interferon beta-1a at a dose of 30 ?g per week for up to 2 years. The focus was on annualized relapse rate. In the industry-funded study, 107 patients were assigned to fingolimod and 108 to interferon beta-1a.

Researchers report a mean of 2.4 relapses during the preceding 2 years, for an adjusted annualized relapse rate of 0.12 with fingolimod and 0.67 with interferon beta-1a.

Annualized rate of new or newly enlarged lesions on T2-weighted MRI—the key secondary end point—was 4.39 with fingolimod and 9.27 with interferon beta-1a, they add.

In terms of adverse events other than MS relapses, 88.8% of patients who received fingolimod and 95.3% of those who received interferon beta-1a experienced them, according to the report.

Nearly 17% of patients had serious adverse events in the fingolimod group, including infection in four patients and leukopenia in two patients, with six patients experiencing convulsions, researchers report. Of the interferon beta-1a group, 6.5% of patients had serious adverse events, with infection in two patients and supraventricular tachycardia in one.

“Among pediatric patients with relapsing multiple sclerosis, fingolimod was associated with a lower rate of relapse and less accumulation of lesions on MRI over a 2-year period than interferon beta-1a but was associated with a higher rate of serious adverse events,” wrote the study authors, who called for longer studies to determine the durability and safety of fingolimod in pediatric MS.

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