Zelquistinel or Placebo for the Reduction of Symptoms of Major Depressive Disorder

This is a Phase 2 multicenter, randomized, double-blind, placebo-controlled, parallel-group, fixed dose clinical trial designed to evaluate the safety and efficacy of zelquistinel versus placebo in subjects with symptoms of major depressive disorder. Each subject will participate in this study up to 98 days: up to 28 days for screening, 42 days for double-blind treatment, and a 4-week follow-up period. Subjects will return to the clinic one time each week to have the severity of their depression assessed using the Hamilton depression rating scale-17. Adverse events that occurred since the last study visit will be recorded.