Extended-release Guanfacine Hydrochloride in Children/Adolescents With Attention-deficit/Hyperactivity

Phase 3,Double Blind,Placebo-controlled,Multicentre,Randomised-withdrawal,Long-term Maintenance of Efficacy&Safety Study of Extended-release Guanfacine Hydrochloride in Children/Adolescents Aged 6-17 With ADHD

A study to evaluate the long term maintenance of efficacy of using Guanfacine Hydrochloride (SPD-503) for the treatment of ADHD in Children aged 6-17 years in Europe, Australia, Canada and the US.

The SPD503-315 clinical program has studied the efficacy, safety, and tolerability of this product in treating symptoms of ADHD in children and adolescents aged 6-17 through short-term, placebo-controlled studies and long-termn, open-label studies. This study will more rigorously assess the long-term maintenance of efficacy using a placebo-controlled, randomised-withdrawal design. To date, all of the completed studies conducted as part of the SPD503 proigram have enrolled subjects from the US. This study is designed to evaluate the long-term maintenance of efficacy of SPD503 for the treatment of ADHD in children aged 6-17 years in Europe, Australia, Canada and US.

Inclusion Criteria:

• male or female, aged 6-17 years at the time of consent/assent at Screening/Visit 1
• subject meets DSM-IV-TR criteria for primaru diagnosis of ADHD
• subject has a minimum ADHD-RS-IV total score of 32 at enrolment/visit 2
• subject has a minimum CGI-S score of 4 at Enrolment/Visit 2
• subject is able to swallow intact tablets

Exclusion Criteria:

• subject has a current controlled or uncontrolled, co-morbid psychiatric diagnosis.
• subject has a know history or presence of structural cardiac abnormalities
• subject with orthostatic hyupotension or a known history of controlled or uncontrolled hypertension
• current use of any prohibited medication or other medications, including herbal supplements that affet blood pressure, or heart rate or that have CNS effects or affect cognitive performance
• subject is significant overweight based on Centre for disease control and prevention BMI for age gender specific charts. Significantly overweight is defined as a BMI >95 th percentile Children aged 6-12 years with a body weight ,25,0kg, or adolescents aged 13-17 years with a body weight <43 kg or >91 kg at screening/visit 1
• subject is currently considered a suicide risk in the opinion of the investigator
• history of failure to respond to an adequate trial of an alfa2-agonist for the treatment of ADHD.