Efficacy, Safety and Tolerability of CX157 in Treatment Resistant Depression

Inclusion Criteria: 1. Male or female, 20 to 65 years of age 2. Able to read, understand and converse in English and provide written, dated informed consent 3. Diagnosed with Major Depressive Disorder (MDD)and Treatment Resistant Depression(TRD) 4. Females on acceptable method of contraception Exclusion Criteria: 1. Major depressive episode greater than five years 2. A history of a Substance Use Disorder with the exception of nicotine dependence in the past 12 months 3. Obsessive-Compulsive Disorder (OCD), Panic Disorder, Post-traumatic Stress Disorder (PTSD 4. A history of schizophrenia or schizoaffective disorders 5. A history of anorexia nervosa, bulimia nervosa, or eating disorder not otherwise specified, within the past five years 6. A history of Antisocial Personality Disorder or Borderline Personality Disorder 7. Recent suicidal behavior and is at risk of such behavior during the course of the study 8. Electroconvulsive therapy (ECT) within the past five years 9. Transcranial Magnetic Stimulation (TMS) for the treatment of the current episode of depression 10. Vagus Nerve Stimulation (VNS) at any time 11. Any psychoactive drugs within one to four weeks prior to the randomization visit depending on the type of drug 12. Significant abnormality on the screening physical examination 13. Significant cardiac abnormalities such as uncontrolled hypertension, recent myocardial infarction, Congestive heart failure (CHF), Angina pectoris 14. A history within the past two years of significant head trauma, surgical procedure involving the brain,degenerative central nervous system disorder (e.g., Alzheimer's or Parkinson's Disease), epilepsy, mental retardation 15. A history of hypothyroidism and has been on a stable dosage of thyroid replacement medication for less than six months 16. A history of hyperthyroidism which was treated (medically or surgically) less than six months prior to screening 17. Participation in an investigational study in the past one month 18. A positive screening urine test for drugs of abuse 19. Female subject who is pregnant or lactating