Subcutaneous interferon Beta-1a in pediatric multiple sclerosis: a retrospective study.

To expand current knowledge, we examined the safety and tolerability of subcutaneous interferon β-1a in patients with pediatric-onset multiple sclerosis. Records from 307 patients who had received at least 1 injection of subcutaneous interferon β-1a for demyelinating events when aged younger than 18 years were reviewed. Overall, 168 (54.7%) patients had at least 1 prespecified medical event related to or under close monitoring with subcutaneous interferon β-1a or specific to pediatric patients, 184 (59.9%) had nonserious medical events related to treatment or of unknown causality, and 12 (3.9%) had serious medical events irrespective of causality. The most common laboratory abnormalities were increased alanine (74/195; 37.9%) and aspartate aminotransferase levels (59/194; 30.4%). Annualized relapse rates were 1.79 before treatment and 0.47 during treatment. In conclusion, adult doses of subcutaneous interferon β-1a (44 and 22 μg, 3 times weekly) were well tolerated in pediatric patients and were associated with reduced relapse rates.