The FDA has agreed a regulatory route for Shire’s attention deficit hyperactivity disorder (ADHD) product for adults, potentially opening up a lucrative new market for the company’s franchise.
Most cases of ADHD are diagnosed in children, and the prevailing wisdom has been that in most cases symptoms resolve as patients reach maturity. However, the adult form of the disorder is also remarkably common, with an estimated prevalence of up to 5%, and is considered to be the most severe long-term outcome of this neurodevelopmental disorder.
Shire wants to develop a drug called SHP465 (triple-bead mixed amphetamine salts) for adult ADHD, but to satisfy the FDA will have to first carry out a trial of the formulation in children, as was first revealed by the company last October.
The company had initially hoped to launch the product later this year, but the new regulatory route means that a timeframe of 2017 is more likely. The first patient is due to be enrolled into the paediatric trial in August.
“Adult patients with ADHD represent the fastest growing segment of the overall ADHD patient population,” said Shire in a statement.
Breaking into the adult ADHD – as well as a sideways move into binge-eating disorder with paediatric ADHD therapy Vyvanse (lisdexamfetamine) – could eventually double sales of Shire’s psychiatric portfolio by 2020, according to chief executive Flemming Ornskov.
Last year, the company’s psychiatric drugs brought in around $2.2bn in sales and royalties, a little over a third of its total annual revenues of $6bn.
Adults already receive treatment for ADHD off-label using drugs such as Adderall and Adderall XR – both also based on mixed amphetamine salts – but it is though that a sizeable proportion use the long- and short-acting form sequentially in order to control symptoms throughout the day.
SHP465 will provide 16 hours cover from a single tablet, extending from the morning into the evening, according to Shire, which also expects the new formulation to claim three years’ additional market exclusivity in the US, extending its patent protection out to 2029.