Shire plc and Shionogi & Co. Ltd. are seeking Japanese approval for their attention deficit hyperactivity disorder drug Intuniv.

Shionogi submitted a new drug application to expand the indication to include adults with ADHD. The drug, an extended release formulation of guanfacine hydrochloride, is already approved to treat 6 to 17 year-old ADHD patients.

The application is backed by data from a phase 3 study in which Intuniv outperformed placebo at improving global functioning in adults with ADHD.

Dublin's Shire and Japan-based Shionogi are co-developing and commercializing Intuniv under a 2011 licensing contract.

Intuniv is already approved in 36 countries to treat ADHD in children and adolescents. Shire said Japan is the world's third largest ADHD market.