d-Amphetamine Transdermal System in Treatment of Children and Adolescents with Attention-Deficit/Hyperactivity Disorder: Secondary Endpoint Results and Post Hoc Effect Size Analyses from a Pivotal Trial.

Objectives: Amphetamines are a preferred treatment for attention-deficit/hyperactivity disorder (ADHD), with the dextroamphetamine transdermal system (d-ATS) providing an alternative to oral formulations. A pivotal trial of d-ATS in children and adolescents with ADHD met primary and key secondary endpoints. This analysis reports additional endpoints and safety findings from the pivotal trial and evaluates effect size and number needed to treat (NNT) for d-ATS. Methods: In this study, a 5-week, open-label dose-optimization period (DOP) preceded a 2-week, randomized, crossover double-blind treatment period (DBP). Eligible patients received d-ATS 5 mg during the DOP, with weekly evaluations for increase to 10, 15, and 20 mg (equivalent to labeled doses of 4.5, 9, 13.5, and 18 mg/9 hours, respectively) until reaching and maintaining the optimal dose, which was utilized for the DBP. Secondary endpoints included assessment of Attention-Deficit/Hyperactivity Disorder Rating Scale IV (ADHD-RS-IV), Conners' Parent Rating Scale Revised Short Form (CPRS-R:S), and Clinical Global Impression (CGI) scores. NNT was calculated for ADHD-RS-IV and CGI-Improvement (CGI-I). Safety assessments included treatment-emergent adverse events (TEAEs) and dermal safety. Results: In total, 110 patients entered the DOP, with 106 patients randomized (DBP). During the DBP, the least-squares mean (95% confidence interval) difference for d-ATS versus placebo in ADHD-RS-IV total score was -13.1 (-16.2 to -10.0; p < 0.001), with effect size of 1.1 and NNT of 3 for ADHD-RS-IV remission, ≥30% improvement, and ≥50% improvement. Significant differences between placebo and d-ATS were also observed for CPRS-R:S and CGI-I scales (p < 0.001), with NNT of 2 for CGI-I response. Most TEAEs were mild or moderate, with three leading to study discontinuation in the DOP and none in the DBP. No patients discontinued due to dermal reactions. Conclusions: d-ATS was effective in treating ADHD in children and adolescents, meeting all secondary endpoints, with a large effect size and NNT of 2-3 to achieve a clinically meaningful response. d-ATS was safe and well tolerated, with minimal dermal reactions. Clinical Trial Registration: NCT01711021.

Efficacy and Safety of Dextroamphetamine Transdermal System for the Treatment of Attention-Deficit/Hyperactivity Disorder in Children and Adolescents: Results from a Pivotal Phase 2 Study.

Objectives: To assess efficacy and safety of the new Dextroamphetamine Transdermal System (d-ATS) to treat children and adolescents (aged 6-17 years) with attention-deficit/hyperactivity disorder (ADHD). Methods: In this phase 2, randomized, placebo-controlled study, 4 d-ATS patches of differing doses (5, 10, 15, and 20 mg) were evaluated. Patients began a 5-week, open-label, stepwise dose-optimization period in which they received a 5-mg d-ATS patch (applied to hip) for 9 hours. During weekly visits, patients were evaluated for possible adjustments to the next dose level based on efficacy and safety. Once at the optimal dose, that dose was maintained during a 2-week, crossover double-blind treatment period. Primary endpoint was to assess efficacy of d-ATS versus placebo as measured by Swanson, Kotkin, Agler, M-Flynn, and Pelham Scale (SKAMP) total score; key secondary endpoints included assessing onset and duration of efficacy by SKAMP total score, and additional secondary endpoints included Permanent Product Measure of Performance (PERMP) scores. Safety was assessed throughout. Results: d-ATS treatment resulted in significant improvements versus placebo in ADHD symptoms as measured by SKAMP total score, with overall least-squares mean difference (95% confidence interval) versus placebo of -5.87 (6.76, -4.97; p < 0.001) over the 12-hour assessment period. Onset of efficacy was observed at 2 hours postdose (p < 0.001), and duration of effect continued through 12 hours (patch removed at 9 hours), with significant differences between d-ATS and placebo at all time points from 2 hours onward (all p ≤ 0.003). Significant improvements versus placebo in PERMP-A and PERMP-C scores were also observed from 2 to 12 hours postdose with d-ATS treatment. d-ATS was safe and well-tolerated, with a systemic safety profile similar to that observed with oral amphetamines. Conclusions: This study demonstrates that d-ATS is an effective and well-tolerated treatment for children and adolescents with ADHD. These data indicate that d-ATS can deliver sustained levels of efficacy along with the advantages of transdermal drug delivery, making it a beneficial new treatment option. Clinical Trial Registration no.: NCT01711021.