P-339 - Effect of lisdexamfetamine dimesylate on functional impairment in children and adolescents with attention-deficit/hyperactivity disorder

Abstract

Lisdexamfetamine dimesylate (LDX) is the first long-acting, prodrug stimulant, and is approved in the USA, Canada and Brazil for the treatment of attention-deficit/hyperactivity disorder (ADHD). To evaluate the effect of LDX on functional impairment in patients with ADHD, using the Weiss Functional Impairment Rating Scale-Parent (WFIRS-P). A randomized, double-blind, placebo-controlled trial of an optimized daily dose of LDX was conducted in children and adolescents (6–17 years) with ADHD in Europe. A 4-week dose-optimization period was followed by 3-weeks of dose-maintenance. The WFIRS-P was completed at baseline, day 28 and endpoint. A decrease from baseline indicated an improvement in functional outcomes. Osmotic-release oral system methylphenidate (OROS-MPH) was included as a reference treatment arm. Of 336 randomized patients, 317 were included in the full analysis set and 196 completed the study. Baseline mean (SD) WFIRS-P total scores were similar across treatment groups: LDX, 1.01 (0.45); placebo, 1.10 (0.46); OROS-MPH, 1.07 (0.44). The least squares (LS) mean decrease (95% confidence intervals) in WFIRS-P total score from baseline to endpoint was statistically significantly greater with LDX than with placebo (difference of −0.3 [−0.4, −0.2], p < 0.001), with an effect size of 0.924 for LDX. The difference in LS mean change from baseline to endpoint between OROS-MPH and placebo was −0.2 (−0.3, −0.1; p < 0.001) in favour of OROS-MPH (effect size, 0.772). LDX was more effective than placebo in improving functional impairments in children and adolescents with ADHD. By funding from Shire Development Inc.