Open-label Study of Safety and Tolerability of Memantine in Children With Autism

This is a 48-week multicenter extension study comprised of a 6-week double-blind dose-titration period followed by a 42-week open-label maintenance period. In the Forest autism trials conducted in children ages 6-12, dosing with an extended release formulation of memantine was weight-based. These weight based dose limits were selected to ensure exposure in terms of area under the curve (AUC) was less than the predefined limit of 2100 ng∙h/mL that represented a 10-fold lower exposure than observed at the NOAEL (No observed adverse effect level) of 15 mg/kg/day in juvenile rats. The weight-based dose limits in these studies were as follows: * Group A: ≥ 60 kg; max 15 mg/day * Group B: 40-59 kg; max 9 mg/day * Group C: 20-39 kg; max 6 mg/day * Group D: \< 20 kg; max 3 mg/day