Efficacy and Safety of Duloxetine in Children and Adolescents with Major Depressive Disorder in Japan: A Randomized Double-Blind Placebo-Controlled Clinical Trial Followed by an Open-Label Long-Term Extension Trial

Efficacy of Preventing Relapse Evaluated by a Multicenter Randomized Double-Blind Placebo-Controlled Withdrawal Study of Escitalopram in Japanese Adolescents with Major Depressive Disorder

Objective: To evaluate the efficacy and safety of escitalopram (ESC) in a 48-week relapse prevention study in Japanese adolescents with major depressive disorder (MDD). Methods: This was a 48-week multicenter randomized double-blind placebo-controlled parallel-group study of patients aged 12-17 years with MDD. Patients received ESC for 12 weeks as an open-label treatment period (open-label period). Patients who achieved criteria for remission or response in the open-label period received either ESC or placebo for 36 weeks as a double-blind treatment period (double-blind period). The primary endpoint was the time to relapse during the double-blind period. Safety was evaluated in terms of type, incidence, and severity of adverse events. Results: Of the 128 patients who entered the open-label period, 80 patients entered the double-blind period, all of whom were in the primary analysis population. The primary endpoint, time to relapse, was marginally less than statistically significant between the ESC and placebo groups (p = 0.051, log-rank test). In the Cox proportional hazards model, the estimated hazard ratio [two-sided 95% confidence interval] for relapse in the placebo group versus the ESC group was 2.96 [0.94, 9.30]. There were statistically significant differences between the ESC and placebo groups in several secondary endpoints (change in Children's Depression Rating Scale-Revised, change in Clinical Global Impressions-Severity Scale, etc.). No notable safety/tolerability issues were observed in this study compared with the results of studies in Japanese adults with MDD. Conclusions: Superiority of ESC over placebo for relapse prevention in Japanese adolescents aged 12-17 years with MDD could not be verified with time to relapse evaluated by log-rank test. However, secondary endpoint results and a post hoc analysis of time to relapse suggest that ESC may be effective in preventing MDD relapse. No notable safety/tolerability issues were observed compared with the results of studies in Japanese adults with MDD. Study Registry Number: jRCT2080224520.

Factors Related to Placebo Response in Randomized, Double-Blind Clinical Trials of Antidepressants in Children and Adolescents: A Meta-regression Analysis

BACKGROUND AND OBJECTIVE

Many randomized clinical trials (RCTs) for antidepressants in children and adolescents have failed to demonstrate efficacy due to a high placebo response. The aim of this study was to identify the potential factors affecting placebo response using meta-regression analysis of RCTs for antidepressants in children and adolescents using the Children's Depressive Rating Scale-Revised (CDRS-R) as the outcome.

METHODS

PubMed and ClinicalTrials.gov were searched for randomized, double-blind, placebo-controlled trials of antidepressants for the acute treatment of major depressive disorder in children and adolescents. The outcome used in the present study was the mean change of the CDRS-R total score from baseline to the last assessment for the primary efficacy in the placebo arm. Potential factors related to the placebo response, such as study design, operational, and patient factors, were explored using meta-regression.

RESULTS

The analyses included 23 trials. On multivariable meta-regression, setting up a placebo lead-in period was significantly associated with a smaller placebo response in the CDRS-R.

CONCLUSION

Setting up a placebo lead-in period should be considered in future clinical trials of antidepressants in adolescents and children.

Population pharmacokinetics of duloxetine in Japanese pediatric patients with major depressive disorder

The objectives of this analysis were to characterize the pharmacokinetics of duloxetine in Japanese pediatric patients aged 9-17 years with major depressive disorder (MDD) and to explore potential intrinsic factors affecting its pharmacokinetics. A population pharmacokinetic (PK) model was developed with plasma steady-state duloxetine concentrations from Japanese pediatric patients with MDD in an open-label long-term extension trial in Japan (ClinicalTrials.gov Identifier: NCT03395353). Duloxetine pharmacokinetics in Japanese pediatric patients was well described by a one-compartment model with first-order absorption. The population mean estimates of CL/F and V/F of duloxetine were 81.4 L/h and 1170 L, respectively. Patient intrinsic factors were assessed for their potential influence on duloxetine apparent clearance (CL/F). Only sex was identified as a statistically significant covariate of duloxetine CL/F. Duloxetine pharmacokinetic parameters and model-predicted duloxetine concentrations at steady state in the Japanese pediatric population were compared with those in Japanese adults. The mean duloxetine CL/F in pediatrics is slightly higher than adults, it is, however, expected that comparable steady-state duloxetine exposure in pediatric patients can be achieved with the approved dose regimen for adults. The population PK model provides useful information to understand the pharmacokinetic characteristics of duloxetine for Japanese pediatric patients with MDD. CLINICALTRIALS.GOV IDENTIFIER: NCT03395353.