Pharmacokinetics and Tolerability of Single-Ascending Doses of Desvenlafaxine Administered to Children and Adolescents with Major Depressive Disorder

To investigate the safety and pharmacokinetic profile of ascending doses of desvenlafaxine in children and adolescents with major depressive disorder. Assessment of the effect of desvenlafaxine on depression symptoms was exploratory. The 8-week, open-label study included an initial 3.5-day inpatient period followed by a 7.5-week outpatient period. Children (7-11 years) received a single desvenlafaxine dose of 10, 25, 50, or 100 mg on day 1; adolescents (12-17 years) received desvenlafaxine 25, 50, 100, or 200 mg/day. Plasma and urine samples were collected over the initial 72-hour inpatient period. Evaluations included treatment-emergent adverse events (TEAEs), physical examinations (including Tanner Staging), vital signs, laboratory assessments, 12-lead electrocardiogram, Columbia-Suicide Severity Rating Scale, and the Children's Depression Rating Scale-Revised (CDRS-R). In all, 29 children and 30 adolescents took at least one dose of desvenlafaxine and were included in the safety population (children: 10 mg, n = 6; 25 mg, n = 7; 50 mg, n = 9; 100 mg, n = 7; adolescents: 25 mg, n = 7; 50 mg, n = 7; 100 mg, n = 8; 200 mg, n = 8). Total area under the drug concentration-time curve from 0 to infinity (AUC) appeared to increase linearly with increasing dose. Mean (standard deviation [SD]) AUC ranged from 628 (346) ng/mL (desvenlafaxine 10 mg) to 6732 (3031) ng/mL (100 mg) in children and from 1123 (361) ng/mL (25 mg) to 11,730 (3113) ng/mL (200 mg) in adolescents. During the combined inpatient and outpatient period, 16/29 (55%) children and 21/30 (70%) adolescents reported at least one TEAE. One serious adverse event (suicidal behavior) was reported. Mean (SD) change from baseline in CDRS-R total scores at week 8 was -19.00 (9.87) for children and -21.57 (11.50) for adolescents. Desvenlafaxine AUC values increased linearly with dose; body weight alone provided an adequate prediction for dose-normalized AUC. Desvenlafaxine was generally safe and well tolerated in children and adolescents for treatment up to 8 weeks.