After more than a decade, Shire has finally won approval in the US for its long-acting attention deficit hyperactivity disorder drug (ADHD) Mydayis.
The longer-acting drug – which was first submitted to the FDA back in 2006 but turned down by the regulator – has the same active ingredient as Shire’s older drug Adderall XR (mixed amphetamine salts) and is due to reach the US market in the third quarter of the year.
Its formulation means that it can provide symptom control for up to 16 hours – as opposed to the 12-14 hours currently offered by rival treatments – giving people with ADHD cover from morning until night from a single dose taken upon wakening. Its effects generally kick in two to four hours after dosing.
Being able to take a single dose is important, according to Shire because it is thought that more than half (56%) of adult patients with ADHD are currently being prescribed more than one pill per day, with 9% taking two extended release pills per day and another 10% taking one extended-release product as well as one immediate-release product to manage symptoms. Around 4% of adults are estimated to have the condition in the US.
Formerly known as SHP465, Mydayis has been approved to treat ADHD in children aged over 13 and adults, as in younger patients it has higher rates of adverse reaction such as insomnia and decreased appetite.
Shire has previously suggested the new drug would be its most important 2017 launch and could be worth around $500m a year in peak sales, although consensus analyst estimates a more modest $288m by 2020, mainly because of anticipated payer resistance in the US as the new drug has the same ingredients as Adderall XR.
Jefferies points out however that “every ADHD drug Shire launched has outperformed”, and it is predicting $345m in 2020 sales, rising to $425m at peak.
Either way the new drug is a boost to Shire’s ADHD franchise now that Adderall XR and Intuniv (guanfacine) have lost patent protection in most major markets, and along with top ADHD seller Vyvanse (lisdexamfetamine dimesylate) – which pulled in $2bn in sales last year, a rise of 17% and added another $563m in the first quarter.
Vyvanse remains under patent challenge from would-be generic rivals, but so far Shire has successfully defended its brand and reckons it has protection out to 2023.
Shire’s marketing application for Mydayis included data from 16 clinical studies evaluating the drug in more than 1,600 subjects, including results of a short-term efficacy and safety study in paediatric patients with ADHD (aged 6-17) requested by the FDA.