NEW YORK — April 24, 2008 — The US Food and Drug Administration (FDA) has approved lisdexamfetamine dimesylate (Vyvanse) for the treatment of attention-deficit/hyperactivity disorder (ADHD) in adults. Introduced in July 2007 for the treatment of ADHD in children aged 6 to 12 years, lisdexamfetamine is the first and only once-daily prodrug stimulant approved to treat adults with ADHD.

“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, at home, and in relationships, where they have important responsibilities,” said David W. Goodman, MD, Assistant Professor of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, and Director, Adult Attention Deficit Disorder Center of Maryland, Baltimore, Maryland. “The good news is that in a clinical study with adults, one daily dose of [lisdexamfetamine] significantly improved ADHD symptoms of inattention, such as the ability to focus and organize, as well as hyperactivity and impulsivity.”

The phase 3 pivotal trial that led to the FDA approval of lisdexamfetamine to treat adults with ADHD was a double-blind, placebo-controlled, 4-week study with dose escalations in 414 adults aged 18 to 55 years. In this study, adults with ADHD experienced significant improvements in ADHD symptom control within 1 week of treatment with once-daily lisdexamfetamine.(1)

Treatment with lisdexamfetamine at all doses studied (30, 50, and 70 mg) was significantly more effective than placebo, providing a reduction in ADHD Rating Scale (ADHD-RS-IV) scores ranging from 16.2 to 18.6 points at endpoint.(1) Investigators also measured the efficacy of lisdexamfetamine with the Clinical Global Impressions-Improvement (CGI-I) scale and found that the percentage of subjects taking lisdexamfetamine who rated “improved” ranged from 57% to 61% across all doses and was significantly greater than for those taking placebo.(1)

The most commonly reported adverse events in this study were decreased appetite, difficulty falling asleep, and dry mouth.

Lisdexamfetamine 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.(2) The conversion of lisdexamfetamine to d-amphetamine is not affected by gastrointestinal pH and is unlikely to be affected by alterations in normal gastrointestinal transit times.(3)

Lisdexamfetamine is currently available in 3 dosage strengths of 30, 50, and 70 mg, each for once-daily dosing. Additional dosage strengths of 20, 40, and 60 mg lisdexamfetamine have also been FDA-approved and are expected to be available in pharmacies this summer.

References
1. Adler L et al. Efficacy and safety of lisdexamfetamine dimesylate in adults with attention deficit hyperactvity disorder. Paper presented at: 54th Annual Meeting of the American Academy of Child and Adolescent Psychiatry; October 25, 2007; Boston, MA.

2. Biederman J et al. Clin Ther. 2007;29:450-463.

3. Vyvanse [package insert]. Wayne, PA: Shire Pharmaceuticals Inc; 2006.

SOURCE: Shire

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