The purpose of this study is to compare DT-101 and placebo in adult participants with MDD already receiving medication for depression. The clinical study will also evaluate how safe and well tolerated the study drug is. Potential participants will be assessed if they are suitable to take part in the clinical research study by performing physical and neurological examinations, obtaining blood and urine samples, conducting clinical assessments and reviewing medical and treatment history. After successfully passing screening into the study, participants will be randomly assigned to receive either DT-101 or placebo for the study. Over the next 8 weeks, these tests and assessments will continue throughout the study with the purpose of checking the participants' ongoing suitability and to collect data to analyse the effect that DT-101 may have on their depression symptoms. Participants will also have blood samples taken to allow analysis of how DT-101 is absorbed and used by the body.
