Post HOC Analyses of the Efficacy of Lisdexamfetamine Dimesylate in Adults Previously Treated with Attention Deficit/hyperactivity Disorder Medication.

Abstract

Introduction Symptoms of attention-deficit/hyperactivity disorder (ADHD) appear in childhood, but often persist into adulthood. The prodrug lisdexamfetamine dimesylate (LDX) is an effective once-daily treatment for the symptoms of ADHD in children, adolescent and adults. Objectives To evaluate post hoc the impact of ADHD medication history on the efficacy of LDX in adults. Methods In this phase 4, double-blind, dose-optimized study, patients aged 18–55 with ADHD and impaired executive function were randomized (1:1) to LDX or placebo for 10 weeks. Patients well controlled on current ADHD medication with acceptable tolerability were ineligible. Self-reported, lifetime ADHD medication histories were recorded at screening. Investigator-rated ADHD Rating Scale IV with adult prompts (ADHD-RS-IV-Adult) was a secondary efficacy measure. Primary efficacy and safety outcomes have been published (J Clin Psychiatry 2013;74:694–702). Results Baseline characteristics were similar across treatment arms and previous ADHD medication subgroups. Differences between LDX and placebo in mean change from baseline to endpoint in ADHD-RS-IV-Adult total score were observed in the overall study population (n=154; –11.1 [95% confidence interval: –14.96, –7.32]; effect size, 0.9), treatment-naive patients (n=80; –11.4 [–16.81, –5.96]; 0.9) and patients previously treated with: any ADHD medication (n=74; –10.9 [–16.50, –5.30]; 0.9), methylphenidate (n=40; –9.9 [–17.44, –2.45]; 0.9), amfetamine (n=38; –13.8 [–20.86, –6.75]; 1.3) and atomoxetine (n=21; –8.4 [–21.97, +5.26]; 0.6). Conclusion In these post hoc analyses, the response to LDX was similar in the overall study population and subgroups of patients categorized by ADHD medication history. Study funded by Shire Development LLC.