Single-Dose Pharmacokinetics of Amphetamine Extended-Release Oral Suspension (AMPH EROS) in 6–12-Year-Old Children with ADHD

Abstract

Methods

This Phase 1, open-label, single-dose, one-period, one-treatment PK study enrolled 12 children 6–12 y with ADHD. PK parameters for d- and l-amphetamine in plasma (Cmax, tmax, AUC0–8, and t1/2) were calculated and expressed as means, geometric means, and standard deviations. The primary endpoint was all objective PK measurements at 28 hours post-dose. PK was evaluated for 2 cohorts (6 pts ages 6–9 y and 6 pts aged 10–12 y). Safety was monitored continuously and assessed based on occurrence of adverse events.

Results

A single dose of 10 mg (4 ml) AMPH EROS (2.5 mg/ml) administered under fasted conditions resulted in a rapid rise in mean plasma concentration in d-amphetamine, reaching maximum concentrations within 5 hours. The overall study population mean (SD) plasma AUC0–8 (d-amphetamine) was 1061.2 (309) h*ng/mL, and for l-amphetamine was 380.5 (112) h*ng/mL. The mean maximum concentration (Cmax) for the overall study population was 54.91 ng/mL and 17.1 (5.2) ng/mL for d- and l-amphetamine, respectively. The overall study population median time to maximum concentrations (Tmax) for d-amphetamine were reached at 3.4 hours, and for l-amphetamine at 4.1 hours. The elimination half-life (t1/2) for the entire study cohort was 10.6 (2.0) hours for d-amphetamine, and 12.5 (3.2) hours for l-amphetamine. Directionally, a higher mean Cmax, AUC0–8, AUCt, and median Tmax were observed in the younger (6 to 9-year-old) age group, and this result was consistent with both the d- and l-amphetamine enantiomers. The mean elimination t1/2 for both d- and l-amphetamine was higher in the older cohort (10–12 years) than in the 6 to 12-year-olds. Study drug was well-tolerated by the subjects in this study. Two TEAEs were reported in one subject TEAEs (diarrhea and rash on legs) occurred approximately 12 hours postdose.

Conclusions

This study confirmed that the PK profile of AMPH EROS in 6 to 12-year-olds provided a consistent, predictable extended-release profile in a highly titratable liquid formulation, and this finding was relatively consistent and directionally predictable between the age groups assessed, with higher maximum concentrations and AUCs and shorter elimination half-lives noted in the younger population, with no anomalous parameters demonstrated, and no untoward or unexpected safety issues noted.

Funding

Tris Pharma, Inc.