ADHD Drug Designed to Limit Abuse Wins FDA Okay

ROCKVILLE, Md., Feb. 27 -- The FDA has approved lisdexamfetamine dimesylate (Vyvanse), formerly known as NRP104, for attention deficit hyperactivity disorder.

The amphetamine, to be marketed by Shire, is said to have limited abuse potential, but it was designated Schedule II by the DEA. Shire plc said in a statement that the drug has a lower potential for abuse than other amphetamines used to treat ADHD.

"The label we received with the approval letter includes information about the extended duration of effect and abuse-related drug liking characteristics of Vyvanse, which illustrate benefits that differentiate this compound from other ADHD medicines," said Matthew Emmens, Shire's CEO.

Data from phase II and phase III clinical trials demonstrated statistically significant improvements in ADHD symptoms for patients ages six to 12 years treated with lisdexamfetamine compared to patients treated with placebo. These studies demonstrated significant efficacy at all time points tested (including 6 p.m.) for doses of 30 mg, 50 mg, and 70 mg.

In the phase II, analog classroom study, patients showed significantly improved behavior when receiving either lisdexamfetamine or Adderall XR (another Shire drug) as measured by the Swanson, Kotkin, Agler, M. Flynn and Pelham (SKAMP) deportment rating scale, a standardized, validated classroom assessment tool used for evaluating ADHD behavioral symptoms.

Both treatments resulted in significantly improved behavior versus a placebo (P<0.0001, for both). Patients also demonstrated significantly improved academic productivity with both treatments, compared with placebo (P<0.0001 for both medications) as measured by Permanent Product Measure of Performance (PERMP), an age-adjusted collection of math problems that measures a child's ability to pay attention and stay on task as demonstrated by an increase in the number of attempted and successfully completed problems.

In the phase III, randomized, double-blind placebo-controlled study, all three doses of lisdexamfetamine demonstrated significant improvements in ADHD Rating Scale scores compared with placebo (P<0.0001) after four weeks of once-daily treatment.

Moreover, when lisdexamfetamine was administered orally and intravenously in two clinical human drug abuse studies in adults, it produced subjective responses on a scale of "drug liking effects" -- a standardized scale used in clinical abuse studies to measure relative preference -- that were less than d-amphetamine at equivalent doses.

The FDA said the drug will be classified as a Schedule II controlled substance, and the. Drug Enforcement Administration is expected to issue a final scheduling decision following a 30-period for public comment. The company said that it expects a final scheduling decision in time for the company to launch the drug by late June.

The drug was developed by New River Pharmaceuticals, which was acquired by Shire in a deal announced last week.