A Study to Evaluate the Efficacy and Safety of Risperidone (R064766) in Children and Adolescents With Irritability Associated With Autistic Disorder

A Double-blind, Placebo-controlled Study, Followed by an Open-label Extension Study Evaluating the Efficacy and Safety of Risperidone (R064766) in Children and Adolescents With Irritability Associated With Autistic Disorder

The purpose of this study is to evaluate the efficacy of risperidone compared with placebo in children and adolescents with irritability associated with autistic disorder.

This is a randomized (the drug is assigned by chance), 8-week, double-blind (neither physician nor patient knows the treatment that the patient receives), placebo-controlled (placebo is an inactive substance that is compared with a drug to test whether the drug has a real effect in a clinical trial), parallel-group (each group of patients will be treated at the same time), flexible-dose, multicenter study. It will be followed by a 48-week, flexible-dose, open-label (all people know the identity of the intervention) extension, to evaluate the efficacy and safety of risperidone in children and adolescents with a diagnosis of autistic disorder (severe form of pervasive developmental disorder) who have associated irritability. The study consists of up to 2-week screening phase, an 8-week double-blind phase, a 48-week open-label phase, and a 1-week follow-up phase.

Inclusion Criteria:

• Diagnostic for autistic disorder
• A Clinical Global Impression - Severity (CGI-S) score of =>4 and an Aberrant Behavior Checklist - Japanese Version (ABC-J) Irritability Subscale score of =>18
• Patients with mental age of >18 months as measured by appropriate developmental or mental scales
• Patients who have an appropriate caregiver, eg, parent or study-site personnel, who is able to observe the patient's condition, provide information, and evaluate the patient's response appropriately

Exclusion Criteria:

• Patients with previous or current psychotic disorder (eg, schizophrenia, bipolar disorder, or other psychiatric disorders) or with pervasive developmental disorder not otherwise specified, Asperger's disorder, Rett's disorder, pediatric destructive behavior disorder, or substance dependence
• Patients with a clinically significant endocrine, metabolic, cardiac, hepatic, renal, or pulmonary disorder, or hypertension
• Weight of <15 kg at the time of screening and baseline
• Patients with QTc>450 msec in the standard 12-lead electrocardiogram (ECG) at the time of screening
• Patients with known hypersensitivity to risperidone or paliperidone