Long‐term study of lisdexamfetamine dimesylate in Japanese children and adolescents with attention‐deficit/hyperactivity disorder

AIMS: As an extension of a phase 2/3 study evaluating the efficacy and safety of lisdexamfetamine dimesylate (LDX) 30, 50, or 70 mg/d for 4 weeks in Japanese patients aged 6-17 years with attention-deficit/hyperactivity disorder (ADHD), this study evaluated its long-term safety and efficacy. METHODS: This was a multicenter, open-label study of LDX for 53 weeks. Safety was assessed by regular medical examination for treatment-emergent adverse events (TEAEs); regular recording of body weight, vital signs, and laboratory test values; and completion of dependence questionnaires. Efficacy was assessed using Japanese versions of the ADHD-Rating Scale-IV (ADHD-RS-IV) and Conners' 3rd edition Parent Rating Scale (Conners 3); plus Clinical Global Impression-Improvement (CGI-I), Clinical Global Impression-Severity, and Parent Global Assessment (PGA) scales. RESULTS: Of 132 enrolled patients, 104 completed the trial. Most frequent treatment-related TEAEs were decreased appetite (73.5%), initial insomnia (39.4%), and weight decrease (22.0%). Most TEAEs were mild (82.6% of patients). There were no serious or severe TEAEs or deaths. No treatment-related TEAEs were associated with blood pressure or pulse rate, and no patient had a QTcF interval >500 ms. Statistically significant improvement from baseline to week 53 was observed in the mean ADHD-Rating Scale-IV total score and mean Conners 3 subscale scores. Most patients showed improvement on the CGI-I (78%) and PGA (76.5%) scales. CONCLUSIONS: No significant safety issues were observed with LDX 30, 50, or 70 mg/d administered for 1 year in Japanese children and adolescents with ADHD. LDX was associated with long-term reductions in ADHD symptoms and severity.