The disease-modifying therapies that have revolutionized multiple sclerosis (MS) treatment for adults are not specifically approved for treatment of children with MS. However, although the evidence for treating pediatric MS is relatively scarce, there is sufficient reason to offer these options.
Here Dr So, coauthor of a recent review on treatment of pediatric MS,1 offers insights into current practice.
How common is MS in the pediatric population, and how does it differ from adult MS?
The onset of MS in pediatric patients is actually not that common; it is believed to occur in approximately 3% to 5% of the population. In general, the symptoms of pediatric MS are similar to those of adults, with the exception that pediatric patients may have more isolated optic neuritis, symptoms of encephalopathy, and isolated brainstem dysfunction. Also, children have a longer onset to secondary progression.
What options exist for treatment of pediatric MS? Are children's responses significantly different than those of adults with MS?
The two main options for the treatment of pediatric MS today include interferons and glatiramer acetate(Drug information on glatiramer acetate). Two forms of interferon (INF) are available: INF-β1a (one formulation is administered intramuscularly once weekly and the other subcutaneously 3 times per week) and INF-β1b (subcutaneously every other day). Only one formulation of glatiramer acetate is currently available—a once-daily subcutaneous injection.
Fingolimod is a newer option for adult MS, but no information currently exists regarding its use in the pediatric population.
Efficacy studies on INFs and glatiramer are limited in the pediatric population; they are mostly in the forms of observational studies and case reports. One moderately large Italian study did find that the efficacy of these agents is relatively similar, and they all provided a reduction in the annual relapse rate in the cohort.
Adverse events are also relatively similar to those in the adult population; flu-like symptoms develop with all the agents. Also, the use of INFs may also lead to abnormal liver function test results.
What guidelines exist for treatment of pediatric MS?
A recent consensus statement (2012) has been published in Multiple Sclerosis on new and existing therapeutic options for pediatric MS.2
What’s the best course of action once MS is definitively diagnosed in someone younger than 18? What factors should guide the choice of initial treatment?
Once MS is diagnosed in a pediatric patient, clinicians usually do not initiate therapy with a disease-modifying agent until a second demyelinating episode has developed. Since the efficacy of agents currently available to pediatric patients is relatively similar, clinicians should decide on the initial agent based on potential adverse effects and the patient’s preferences. For example, if a patient has a needle phobia, then a once-weekly intramuscular injection of INF-β1a may be appropriate.
What is the accepted practice with regard to defining treatment failure in a pediatric patient? How do most specialists proceed when a disease-modifying treatment appears not to be working?
The initial treatment can be considered as a failure if a patient (1) often requires plasma exchange and/or immunoglobulin infusion, (2) experiences as many or more relapses as before therapy, or (3) experiences disease progression by at least 2 points on the Expanded Disability Status Scale (EDSS) for more than 3 months.
No studies exist thus far to guide clinicians on alternative therapy once initial therapy has failed. However, most clinicians switch to another first-line agent.