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Protocol Details

An Investigation of the Antidepressant Effects of the Glycine Receptor Antagonist AV 101 (4-chlorokynurenine) in Major Depressive Disorder

This study is NOT currently recruiting participants.

Summary | Eligibility | Citations | Contacts




Sponsoring Institute

National Institute of Mental Health (NIMH)

Recruitment Detail

Type: Completed Study; data analyses ongoing
Gender: Male & Female
Min Age: 18 Years
Max Age: 65 Years

Referral Letter Required


Population Exclusion(s)

Non-English Speaking;


Major Depression;
Glycine Receptor Antagonist;
Treatment Resistant;
Glutamatergic System

Recruitment Keyword(s)



Major Depression

Investigational Drug(s)

AV 101 (4-Chlorokynurenine)

Investigational Device(s)



Drug: AV 101 (4-Chlorokynurenine)
Drug: Placebo Comparator

Supporting Site

National Institute of Mental Health


- Drugs and talk therapy help treat depression, but these treatments usually take quite a bit of time to work. Ketamine is a fast-acting antidepressant, but it has side effects like unusual dreams and experiences. The drug AV-101 may have the same antidepressant effects but fewer side effects. Researchers want to see if it is effective and safe for people with major depressive disorder.


- To see if the drug, AV-101 is safe and if it treats symptoms of major depressive disorder.


- Adults ages 18-65 with major depression without psychotic features.


- Participants will be screened under a separate protocol.

- Participants will stay in the hospital for 12-14 weeks.

- Phase 1 (2-7 weeks): participants will stop taking their medicines then not take any for 2 weeks. They will have several scans and other procedures.

- Phase 2 (6-7 weeks): 2 weeks each of study drug and placebo once a day, with 2 weeks of no drugs in between.

- Participants will have:

- Physical exams

- Interviews

- Frequent blood collection. A needle will place a small plastic tube in the arm. Some blood samples will be taken through this tube.

- 2 spinal taps (optional). The back will be numbed. A needle will insert a catheter between back bones. That will be left in for up to 30 hours. Spinal fluid will be collected through it.

- 5 scans. Participants will lie in a machine with a magnetic field. The machine takes pictures of the brain and brain chemicals.

- At the end of the study, participants will have medical evaluation, questions, and blood tests. Some may continue treatment at the clinic.

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-18 to 65 years of age.

-Subjects must have a level of understanding sufficient to agree to all required tests and examinations, sign an informed consent document and verify understanding. To verify this, subjects must score greater than or equal to 80% on the consent quiz.

-Subjects must fulfill DSM-IV or DSM-V criteria for MDD, single episode or recurrent without psychotic features, based on clinical assessment and confirmed by a structured diagnostic interview (SCID-P). Subjects must be experiencing a current major depressive episode of at least 4 weeks duration.

-Subjects must have an initial score of at least 18 on the HDRS at screening and at baseline of study phase I.

-Subjects must have a current or past history of lack of response to one adequate antidepressant trial (may be from the same chemical class) operationally defined using the modified-Antidepressant Treatment History Form (ATHF).


-Current psychotic features or a diagnosis of schizophrenia or any other psychotic disorder as defined in the DSM-IV or DSM-V.

-Subjects with a history of DSM-IV drug or alcohol dependency or abuse (or alcohol use disorder per DSM-V),except for caffeine or nicotine dependence within the preceding 3 months.

-Head injury that results in loss of consciousness exceeding 5 minutes (for the imaging component of the study).

-Subjects with a DSM IV or DSM-V Axis II diagnosis of borderline or antisocial personality disorder.

-Pregnant or nursing women or women of child bearing potential not using at least 1 medically accepted means of contraception from the time of enrollment in the study until 1 month after completion of the second phase. Examples of medically accepted means of contraception include oral, injectable, or implant birth control, condom, diaphragm with spermicide, intrauterine devices (IUD), tubal ligation, abstinence or partner with vasectomy. .

-Serious, unstable illnesses including hepatic, renal, gastroenterologic, respiratory, cardiovascular (including ischemic heart disease), endocrinologic, neurologic, immunologic, or hematologic disease.

-Subjects with clinical hyperthyroidism or hypothyroidism.

-Subjects with one or more seizures without a clear and resolved etiology.

-Clinically significant abnormal laboratory tests.

-Treatment with a reversible monoamine oxidase inhibitor (MAOI) within 4 weeks of study phase II.

-Treatment with fluoxetine or aripiprazole within 5 weeks of study phase II.

-Treatment with any other disallowed concomitant medication or TMS 14 days before randomization.

-Treatment with clozapine or electroconvulsive therapy (ECT) within 1 month of randomization.

-Lifetime history of deep brain stimulation.

-Subjects who, in the Principal Investigator's judgment, pose a current serious suicidal or homicidal risk.

-Positive HIV test

-Contraindications to MRS (metal in body, claustrophobia, etc for imaging)

-No structured psychotherapy will be permitted during the total duration of the study. Subjects unable or unwilling to stop psychotherapy will be unable to participate in the study.

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Not Provided

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Principal Investigator

Referral Contact

For more information:

Carlos A. Zarate, M.D.
National Institute of Mental Health (NIMH)
NIHBC 10 - CRC BG RM 7-5342
(877) 646-3644

Carlos A. Zarate, M.D.
National Institute of Mental Health (NIMH)
NIHBC 10 - CRC BG RM 7-5342
(877) 646-3644

Office of Patient Recruitment
National Institutes of Health Clinical Center (CC)
Building 61, 10 Cloister Court
Bethesda, Maryland 20892
Toll Free: 1-800-411-1222
Local Phone: 301-451-4383
TTY: TTY Users Dial 7-1-1

Clinical Trials Number:


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