A Study of Seltorexant Compared to Quetiapine XR as Adjunctive Therapy to Antidepressants in Adult and Elderly Participants With Major Depressive Disorder With Insomnia Symptoms Who Have Responded Inadequately to Antidepressant Therapy

The purpose of this study is to assess the efficacy of seltorexant compared with quetiapine extended-release (XR) as adjunctive therapy to an antidepressant drug in treatment response in participants with major depressive disorder with insomnia symptoms (MDDIS) who have had an inadequate response to current antidepressant therapy with a selective serotonin reuptake inhibitor (SSRI) or serotonin-norepinephrine reuptake inhibitor (SNRI).

Major depressive disorder (MDD) is a common, serious, recurrent disorder. Seltorexant (JNJ-42847922) is a potent and selective antagonist of the human orexin-2 receptor (OX2R) that is being developed for the adjunctive treatment of MDDIS. The hypothesis for this study is that seltorexant is superior to quetiapine XR in leading to a response after 26 weeks of treatment (greater than or equal to \[\>=\] 50 percent \[%\] improvement on baseline Montgomery Asberg Depression Rating Scale \[MADRS\] total score), when administered as adjunctive treatment to an antidepressant in adult and elderly participants with MDDIS who have had an inadequate response to treatment with an SSRI/SNRI. The study will be conducted in 3 phases: a screening phase (up to 30 days), a double-blind (DB) treatment phase (26 weeks), and a post treatment follow-up phase (7 to 14 days after the end of DB treatment phase for all participants, and up to 196 days from baseline for participants who stop study treatment early). The total study duration for each participant will be approximately 32 weeks. Efficacy, safety, pharmacokinetics, and biomarkers will be assessed at specified time points during this study.