US FDA approves Shire's ADHD drug Intuniv

Shire, the UK's third-largest drugmaker, has received approval from the US Food and Drug Administration for Intuniv (guanfacine) extended-release tablets for the treatment of attention-deficit hyperactivity disorder (ADHD) in children and adolescents aged 6 to 17 years.

Intuniv's approval was delayed in July when the FDA issued a complete response letter, following lengthy labeling discussions. Around 4.4 million American children between the ages of four and 17 are diagnosed with ADHD at some point in their lives. Shares of the drugmaker rose 6p to £10.31 on the news of the approval.

The new drug is said to be the first selective alpha-2A adrenergic receptor agonist approved for the treatment of ADHD. Although the mechanism of action is unknown, Intuniv is thought to directly engage receptors found in the prefrontal cortex ' an area of the brain that has been linked in preclinical research to ADHD. Stimulation of the postsynaptic alpha-2A receptors is thought to strengthen working memory, reduce susceptibility to distraction, improve attention regulation, improve behavioral inhibition, and enhance impulse control.

Mike Cola, president of Shire Specialty Pharmaceuticals, said ADHD 'is a complex disorder in which patients may present with multiple symptoms and behaviors that can be disruptive. Intuniv expands the Shire ADHD portfolio with a non-scheduled medication, allowing clinicians to optimize their overall approach toward managing ADHD and may help provide symptom control for children and teens with ADHD who often have difficulty responding appropriately to everyday situations and challenges.'

Once-daily Intuniv is expected to be available in US pharmacies in November and will come in four dosage strengths (1mg, 2mg, 3mg and 4mg).It will be marketed here by the existing Shire ADHD sales team of nearly 600 representatives. The drug is not a controlled substance and has no known potential for abuse or dependence.