Subcutaneous interferon β-1a in pediatric patients with multiple sclerosis: Regional differences in clinical features, disease management, and treatment outcomes in an international retrospective study

BACKGROUND: To further understand management of pediatric patients with multiple sclerosis (MS), we examined disease features, clinical practice patterns, and response to treatment in the United States (US) and seven other countries ('rest of World'; ROW). METHODS: Anonymized data, recorded as part of routine clinical practice, were obtained from medical records (1997-2009) of study participants (who received subcutaneous interferon β-1a before age 18 years) from the US and ROW. Samples were stratified by age (preadolescents [<12 years] and adolescents [12-17 years]). RESULTS: US adolescents had a higher mean body mass index versus ROW adolescents (BMI; 27.2 versus 22.5 kg/m(2)), started disease-modifying therapy (DMT) earlier after the first relapse, were more likely to have received a DMT before initiating subcutaneous interferon β-1a, had a higher relapse rate, and were more likely to switch from subcutaneous interferon β-1a to another DMT before the end of the observation period. CONCLUSIONS: This retrospective analysis of a multinational sample of pediatric MS patients who received subcutaneous interferon β-1a found that those from the US had higher BMI, relapsed more frequently, and were managed differently, compared with ROW patients. Future prospective studies are needed to confirm these observations and ascertain their clinical significance.