Overview

The purpose of this trial is to measure depressive symptoms following treatment with ALTO-207 compared with placebo in participants with TRD.

Eligibility

Inclusion Criteria:

• Male and female participants, ages 18 to 75 years, inclusive, at the time of signing the ICF.
• Prior diagnosis of MDD without psychotic symptoms (in the current episode) and have confirmatory diagnosis of current MDD (moderate to severe).
• Failure to respond (\<50% improvement) to at least 2-5 antidepressant treatments (including the current treatment)
• Currently taking a stable dose of at least 1 but no more than 2 oral antidepressants at baseline

Exclusion Criteria:

• Evidence of unstable medical condition
• Concurrent use of any prohibited medications or substance use disorder
• Diagnosed bipolar disorder or a psychotic disorder or symptoms
• Significant current PTSD symptoms or history of PTSD
• Clinically significant current impulse control difficulties
• Has a history of hypersensitivity or allergic reaction to ALTO-207 or any of its components/excipients
• Concurrent or recent participation in another clinical trial for mental illness involving an investigational product or device