GW320659 for the Treatment of Attention-Deficit/Hyperactivity Disorder in Children

Objective: To assess the safety, tolerability, and efficacy of GW320659, a chemically novel inhibitor of norepinephrine and dopamine reuptake, in pediatric attention-deficit/hyperactivity disorder (ADHD). Method: This was a multicenter, open-label, dose-titration study of seven daily dose levels of GW320659: 1.25, 2.5, 5, 7.5, 10, 12.5, and 15 mg. Treatment began with the lowest dose of GW320659 and increased weekly until subjects (mean age 9.1 years) achieved a maximum acceptable dose. Subjects remained at their maximum acceptable dose for a 4-week treatment period. The key efficacy end-point was clinical response (Clinical Global Impressions of Improvement score of 1 or 2 and an improvement of 5 or more points on at least one of the Conners Parent or Teacher Rating Scales T score). Other end-points included assessments of safety and of quality of life using the Child Health Questionnaire Parent Form 28 (CHQ-PF28). Results: Fifty-one subjects entered the titration phase and 46 subjects completed the study. During the treatment phase, these 46 subjects received a mean dose of 14.2 mg/day and the maximum exposure to GW320659 was 11 weeks. At the end of the treatment period, 76% of subjects showed improvement with GW320659 and there were significant improvements in 7 of the 12 subscales of the CHQ-PF28 compared with baseline (p < .05). Adverse events were generally mild; only five subjects required downward titration because of adverse events (three psychiatric, one neurological and urological, one cardiovascular), and no subject withdrew because of adverse events. Conclusions: GW320659 may have clinically relevant efficacy in pediatric ADHD and was well tolerated in this short-term initial study in children.