Shire plc, the global specialty biopharmaceutical company, has received approval from the US Food and Drug Administration for Vyvanse (lisdexamfetamine dimesylate), for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in adults.

Vyvanse, introduced in July 2007 for the treatment of ADHD in children aged 6 to 12 years, is now the first and only once-daily prodrug stimulant approved to treat adults with ADHD. In its first eight months of availability, more than one million Vyvanse prescriptions have been filled.

"We are very pleased with this FDA approval of the adult indication for Vyvanse," said Matthew Emmens, chief executive officer of Shire. "This approval provides physicians a new treatment option that can help their adult patients by significantly improving their ADHD symptoms. Vyvanse has been well accepted by the medical community. With Shire's experience as a leader in the development and commercialization of ADHD medications, we are confident that this approval for adult patients will help continue to increase prescription share and volume of Vyvanse".

"Many people may think of ADHD as only a childhood disorder but the fact is that the majority of children diagnosed with ADHD still have symptoms as an adult. These symptoms can significantly impact them at work, home and in relationships, where they have important responsibilities," said David W Goodman, assistant professor of psychiatry and behavioural sciences at Johns Hopkins University School of Medicine and director of the Adult Attention Deficit Disorder Centre of Maryland. "The good news is that in a clinical study with adults, one daily dose of Vyvanse significantly improved ADHD symptoms of inattention, such as the ability to focus and organize, as well as hyperactivity and impulsivity".

Since Vyvanse became available for children with ADHD in July 2007, the product has achieved a US market share of 6.9 per cent based on weekly branded prescription volume Vyvanse formulary coverage has been positive, with the top six managed care plans now covering the product in a preferred formulary position.

Vyvanse is a therapeutically inactive prodrug, in which d-amphetamine is covalently bonded to l-lysine, and after oral ingestion it is converted to pharmacologically active d-amphetamine. The conversion of Vyvanse to d-amphetamine is not affected by gastrointestinal pH and is unlikely to be affected by alterations in normal GI transit times.

Vyvanse is currently available in three dosage strengths of 30 mg, 50 mg and 70 mg, each for once-daily dosing. Additional dosage strengths of 20 mg, 40 mg and 60 mg Vyvanse have also been FDA-approved and are expected to be available in pharmacies this summer.