A Study to Assess the Effect and Safety of AZD6765 in Patients With Major Depressive Disorder

A Multicenter, Randomized, Double-blind, Parallel Group, Placebo-controlled, Phase IIb
Efficacy and Safety Study of Adjunctive AZD6765 in Patients with Major Depressive Disorder
(MDD) and a History of Inadequate Response to Antidepressants

Inclusion Criteria:

- Provision of signed and dated informed consent before initiation of any study-related
procedures.

- Male or female patients aged 18 to 70 years, inclusive.

- The patient must have a clinical diagnosis of major depressive disorder with a
lifetime history of inadequate response to at least 3 antidepressants.

- Women of child-bearing potential must have a negative serum pregnancy test and
confirmed use of a highly effective form of birth control before enrollment for a
minimum of 3 months before study start.

- Outpatient status at screening and randomization visits.

Exclusion Criteria:

- Patients with a history of diagnosed bipolar disorder or schizophrenia or
schizoaffective disorder or currently exhibiting psychotic features associated with
their depression; dementia or suspicion thereof.

- Patients who have had a suicide attempt within the last 6 months.

- Electroconvulsive therapy (ECT), vagal nerve stimulation (VNS) or transcranial
magnetic stimulation (TMS) or previous treatment with ketamine infusion within the 6
months prior to screening, or any history of deep brain stimulation.

- Patients with any history of seizure disorder (except for febrile seizures in
childhood).

- Pregnancy or lactation.