Data from a Phase III study evaluating Shire’s Intuniv in Japan in adults with attention deficit hyperactivity disorder indicate that the drug could improve symptoms of the condition in this patient group.

Intuniv (guanfacine) is a selective alpha-2A adrenergic receptor agonist that offers a unique mechanism of action in ADHD.

Preclinical studies suggest that the drug may exert physiological effects by selectively stimulating the alpha-2A adrenergic receptor in the prefrontal cortex, a region of the brain known to control several cognitive functions including attention and social behaviours.

According to Shire and its partner in Japan Shionogi, the first ever clinical trial to evaluate Intuniv in adults with ADHD has met its primary endpoint, demonstrating that, when administered as a once-daily dose, the drug was superior to placebo with respect to the change from baseline on a clinically administered ADHD rating scale.

Intuniv also showed nominal significance over placebo at the end of treatment on the clinically important secondary efficacy analysis of the clinical global impression improvement scale (CGI-I), suggesting more patients achieved a marked clinical improvement in global functioning.

Intuniv is a once-daily non-stimulant indicated for the treatment of ADHD in children and adolescents from six to 17 years old.

Shire and Shionogi said they will now evaluate the full data, with a view to expanding reach of the drug to include the treatment of adults with the condition, where they say there is significant unmet demand.

A cross-national analysis of WHO World Mental Health surveys estimates that the prevalence of ADHD at 3.4 percent (range 1.2 percent to 7.3 percent) in adults. Japan is the third largest ADHD market, growing at more than 20 percent a yea