The Effect of Minocycline on Relapse After Successful Intravenous Ketamine/Minocycline-induced Symptoms Response in Subjects With Depression

Inclusion Criteria:

* Diagnostic criteria for moderate to severe major depressive disorder (MDD), without psychotic features, or Bipolar Disorder Type II
* Patients should have an Inventory of Depressive Symptomatology-Clinician Rated (IDS-C30) total score ≥ 34 at Screening and at Day 1 (predose)
* Patients with major depressive disorder should have failed at least two adequate treatment courses (dose and duration) with antidepressant therapy, one of which is in the current episode
* Patients should not have received electroconvulsive therapy (ECT) in the current episode but could be those for whom ECT is considered
* Patients with bipolar depression (BPD) Type II must have been taking a stable dose of a mood-stabilizing medication (e.g., lithium, valproate, carbamazepine, lamotrigine, antipsychotic agents) for at least 4 weeks, dosed clinically to target the therapeutic range
* Patients currently taking an antidepressant(s) must have received at least 2 weeks of stable antidepressant therapy at the time of Screening
* Doses of current antidepressant therapies should remain the same for the duration of the study
* Women must be postmenopausal, surgically sterile, or if heterosexually active, practicing a highly effective method of birth control
* Men who are heterosexually active with a woman of childbearing potential must agree to use a double barrier method of birth control and to not donate sperm during the study and for 3 months after receiving the last dose of study drug

Exclusion Criteria:

* Has a current DSM-IV axis I diagnosis other than MDD or BPD Type II at screening (except for co-morbid anxiety disorders)
* Has a diagnosis of substance abuse or dependence within 6 months prior to screening evaluation (nicotine and caffeine dependence are not exclusionary)
* Patient is currently taking more than 4 psychotropic medications at Day 1 (predose)
* Has an autoimmune disorder such as Crohn's disease, rheumatoid arthritis, psoriasis currently treated with/requiring treatment with immunomodulatory therapies
* Has any significant cardiovascular, respiratory, neurologic, renal, hepatic, endocrine, or immunologic diseases based on screening examination
* Has uncontrolled hypertension (diastolic blood pressure ≥ 90 mmHg), despite diet, exercise or a stable dose of an allowed antihypertensive treatment, at Screening or Day 1 (predose)
* Has planned vaccination within 2 weeks prior to the first dose of study medication through 2 weeks after the last dose of study medication - Has an active infectious disease/current infection
* Has known allergies, hypersensitivity, or intolerance to minocycline or ketamine or its excipients - Has contraindications to the use of minocycline or ketamine per local prescribing information