A long-term open-label safety and effectiveness trial of lisdexamfetamine dimesylate in adolescents with attention-deficit/hyperactivity disorder

Objective: Information on psychostimulant treatment in long-term studies for attention-deficit/hyperactivity disorder (ADHD) in adolescents is limited. This study aimed to assess the safety and effectiveness of lisdexamfetamine dimesylate (LDX) over 52 weeks in adolescents with ADHD. Methods: This open-label multicenter study enrolled eligible participants after their participation in a randomized, double-blind, placebo-controlled 4 week trial in adolescents with ADHD. Following a 4 week dose-optimization phase, participants were maintained on treatment for up to ∼48 weeks on an optimal dose. Safety assessments included treatment-emergent adverse events (TEAEs), vital signs, laboratory findings, and electrocardiograms. Effectiveness measures included the ADHD Rating Scale IV (ADHD-RS-IV; primary) and Clinical Global Impressions-Improvement (CGI-I). The Youth Quality of Life-Research Version (YQOL-R) was also included in this study; raw scores are transformed to a 0-100 point scale. Results: Of 269 enrolled (from the antecedent study), 265 (98.5%) were in the safety population and effectiveness population. Common TEAEs (≥5%) with LDX included upper respiratory tract infection (21.9%), decreased appetite (21.1%), headache (20.8%), decreased weight (16.2%), irritability (12.5%), insomnia (12.1%), nasopharyngitis (7.2%), influenza (6.8%), dizziness (5.3%), and dry mouth (5.3%). At end point, for all LDX doses in the overall safety population, mean (SD) increase from baseline in systolic blood pressure was 2.3 (10.53) mm Hg, diastolic blood pressure was 2.5 (8.37) mm Hg, and pulse rate was 6.3 (12.74) bpm. No clinically meaningful electrocardiogram or vital sign changes were observed. At end point with LDX treatment, the ADHD-RS-IV mean (SD) total score change from antecedent study baseline was -26.2 (9.75) (p<0.001); 87.2% of participants were improved (CGI-I=1 or 2). Baseline (antecedent study) mean (SD) YQOL-R perceptual total score was 79.8 (11.28) and increased by 3.9 (9.73) at end point (p<0.001). Conclusions: LDX demonstrated a long-term safety profile similar to that of other long-acting psychostimulants and was effective, as indicated by improvements in ADHD symptoms and participant-perceived YQOL, in adolescents with ADHD.