A Phase 2 Study of Zelquistinel or Placebo for the Reduction of Symptoms of Major Depressive Disorder

The goal of this clinical trial is to learn if zelquistinel works to treat depression in adults. It will also learn about the safety of zelquistinel. The main questions it aims to answer are: Does zelquistinel reduce depression scores in participants compared to participants who take a placebo (a look-alike tablet that contains no zelquistinel1)? What medical problems are observed in participants who take zelquistinel? Participants will take one tablet of zelquistinel or placebo every week for 6 weeks. Participants will visit the clinic every week of the 6 week period to have the severity of their depression evaluated.

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.