This clinical study was a 12-week, multicenter, double-blind, placebo-controlled, randomized withdrawal study in pediatric outpatients with autism, Asperger's Disorder, or Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS). Patients who completed at least 12 weeks of study drug exposure and met protocol specified responder criterion in lead in Study MEM-MD-91 (NCT01592786) at two consecutive visits separated by at least two weeks were eligible to transition to this study. The responder criterion was defined as having at least a 10 point improvement (reduction in score) in the Social Responsiveness Scale (SRS) total raw score relative to the Visit 1 total raw score in Study MEM-MD-91.~Weight based dose limits were selected in this study to ensure that exposure in terms of area under the curve (AUC) was less than the predefined limit of 2100 ng·h/mL which represents 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 this study were as follows:~Group A: ≥ 60 kg; maximum 15 mg/day~Group B: 40-59 kg; maximum 9 mg/day~Group C: 20-39 kg; maximum 6 mg/day~Group D: < 20 kg; maximum 3 mg/day
The purpose of this randomized withdrawal study is to evaluate the safety, tolerability, and efficacy of memantine compared with placebo in pediatric patients with autism, Asperger's Disorder, or Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS).