Objective: SLI381 (Adderall XR) is a 2-component extended-release capsule formulation of Adderall designed to produce a therapeutic effect that lasts throughout the day with 1 morning dose. The primary objective of this study was to assess the efficacy and safety of SLI381 compared with placebo in the treatment of attention-deficit/hyperactivity disorder (ADHD) in children in a naturalistic school and home setting. A secondary objective was to assess the diurnal variation in responses based on morning and afternoon assessments.
Methods: A multicenter, randomized, double-blind, parallel-group, placebo-controlled trial was conducted at 47 sites. After a 1-week washout of any previous stimulant medication, patients were randomized to receive single-daily morning doses of placebo or SLI381 10 mg, 20 mg, or 30 mg for 3 weeks. Participants aged 6 to 12 years inclusive who satisfied Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria diagnosis of ADHD were included. The primary efficacy parameter was the Conners Global Index Scale for Teachers. Secondary efficacy parameters included the Conners Global Index Scale for Parents, the Clinical Global Impressions Scale for improvement, and the Parent Global Assessment for improvement. Safety was assessed by recording adverse events, laboratory tests, and vital signs at each visit during the study. Physical examinations and electrocardiograms were performed at the screening and the end of the study.
Results: Five hundred eighty-four children were randomized, 563 were included in the intent-to-treat population, and 509 completed the entire study. Intention-to-treat analysis of Conners Global Index Scale for Teachers and Conners Global Index Scale for Parents scores revealed significant improvement in morning, afternoon, and late afternoon behavior for all active treatment groups versus placebo. All active treatment groups showed significant dose-related improvement in behavior from baseline. Both the Clinical Global Impressions Scale for improvement and Parent Global Assessment for improvement showed all doses of SLI381 to be superior to placebo at treatment end and both confirmed the dose-response relationship between improvement and the SLI381 dose. The incidence of spontaneously reported adverse events was low and similar for active treatments and placebo.
Conclusions: SLI381 produced consistent, dose-related improvements on all measures of efficacy. The extended-release nature of the SLI381 formulation was shown by continued, significant improvement in afternoon assessments by teachers and afternoon and late afternoon assessments by parents. The time course and therapeutic effects of SLI381 suggests that this medication is an efficacious once-daily treatment for children with ADHD.