A Phase 2 interventional study of (2R,6R)-hydroxynorketamine (0.25 to 2.0 mg/kg) and Placebo in Suicide, Depressive Disorder, Treatment-Resistant and Ketamine, sponsored by National Institute of Mental Health (NIMH). Recruiting at 1 site in United States. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-10-05.
Sponsored by National Institute of Mental Health (NIMH) · Phase 2, Interventional, and Treatment
Background:
Major depressive disorder (MDD) is a serious mental illness that can put people at risk of self-harm and death. Many drugs are used to treat MDD, but it can take a long time for them to be effective. Researchers want to know if a faster-acting drug, (2R,6R)-hydroxynorketamine (HNK), can better treat the symptoms of MDD.
Objective:
To test a study drug (HNK) in people with MDD.
Eligibility:
People aged 18 to 70 years with MDD. They must have had a screening assessment under protocol 01-M-0254.
Design:
Participants will be tapered off their current MDD drugs over 2 to 5 weeks. They will stay off of the drugs for up to 2 weeks prior to starting the study medication and procedures. They will have a physical exam with blood tests. They will have tests of their heart function, mood, and thinking. They will answer questions about their symptoms. They may choose to have imaging scans and scans of their brain activity.
HNK is given through a tube attached to a needle inserted into a vein. Participants will receive infusions on this schedule:
They will receive 4 infusions over 2 weeks. They will stay in the clinical center overnight after each infusion or for the duration of the study.
They will receive no drugs for 2 to 3 weeks.
They will have 4 more infusions over 2 weeks, with overnight stays after each or for the duration of the study.
One set of 4 infusions will be the HNK. The other set of 4 infusions will be a placebo. A placebo looks just like the real drug but contains no medicine. Participants will not know when they are getting the HNK or placebo.
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Study Description
This is a randomized, double-blind, placebo-controlled, crossover, single-site study.
This experimental study will assess the efficacy and safety of two weeks of 0.25 to 2.0 mg/kg (2R,6R)-hydroxynorketamine (HNK), an enhancer of synaptic glutamate release. The study may be conducted on an inpatient or outpatient basis.
Objectives
Primary Objective
The primary objective is to evaluate the ability of (2R,6R)-HNK, an enhancer of synaptic glutamate release, to improve overall depressive symptomatology in participants with major depressive disorder (MDD). The efficacy of a two-week course of (2R,6R)-HNK will be compared to two weeks of saline placebo in a crossover study. Montgomery-Asberg Depression Rating Scale (MADRS) score will serve as the main outcome measure.
Secondary Objectives
Endpoints
Endpoints Primary Endpoint
Effect of drug on the MADRS total score at day 12.
Secondary Endpoints
Surrogate Markers of Drug Effect, Target Engagement, and Antidepressant Response
448 studies on the registry are indexed under Depressive Disorder, Treatment-Resistant; 147 are open to participants now.
This study's planned enrollment of 50 is below the median of 59 across 372 interventional studies indexed under Depressive Disorder, Treatment-Resistant.
Browse Depressive Disorder, Treatment-Resistant studies →National Institute of Mental Health (NIMH) is the lead sponsor of 367 studies on the registry; 45 are open to participants now.
Of its 25 completed or terminated interventional studies of FDA-regulated products, 24 (96%) have results posted.
Compared within Depressive Disorder, Treatment-Resistant, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Suicide. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
In order to be eligible to participate in this study, an individual must meet all of the following criteria:
EXCLUSION CRITERIA:
An individual who meets any of the following criteria will be excluded from participation in this study:
abnormal laboratory tests specifically defined by:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
A score of how well the liver works in people with liver disease such as cirrhosis: class A is mild, B moderate and C severe.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
DSM diagnostic criteria
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Reproductive potential
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CYP3A (CYP3A4) inhibitors and inducers
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Child-Pugh class
A score of how well the liver works in people with liver disease such as cirrhosis: class A is mild, B moderate and C severe.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Individuals in Arm 1 will receive double-blinded (2R,6R)-HNK infusions four times over two weeks during Test Session 1 and daily double-blinded placebo infusions four times over two weeks during Test Session 2. The starting dose will be 0.25 mg/kg and the treatment target for all participants will be 2.0 mg/kg. If response criteria is not met by the morning of the next infusion, the dose may be increased. Doses will be decreased if tolerability issues arise.
Drug: (2R,6R)-hydroxynorketamine (0.25 to 2.0 mg/kg) · Drug: Placebo
Individuals in Arm 2 will receive double-blinded placebo infusions four times over two weeks during Test Session 2 and double-blinded (2R,6R)-HNK infusions four times over two weeks during Test Session 1. The starting dose will be 0.25 mg/kg and the treatment target for all participants will be 2.0 mg/kg. If response criteria is not met by the morning of the next infusion, the dose may be increased. Doses will be decreased if tolerability issues arise.
Drug: (2R,6R)-hydroxynorketamine (0.25 to 2.0 mg/kg) · Drug: Placebo
Arm 1 and 2 Experimental Intervention
Arm 1 and 2 Control Intervention
Change from baseline on Montgomery-Asberg Depression Rating Scale total scores
Clinical rating scale of depression
Time frame: Baseline, Day 12
Incidence of AEs and total scores using the Clinician Administered Dissociative States Scale, Young Mania Rating Scale, Brief Psychiatric Rating Scale, vital signs, changes in clinical laboratory evaluations, and electrocardiograms.
Measures and evaluations assess various aspects of clinical condition, adverse events, and mood and anxiety symptomology
Time frame: Baseline, 230 min post-drug, and Days 1, 2, 3, 4, 7, 8, 10, 11, and 12, per Test Session.
Change from baseline on the Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale, Positive and Negative Affect Schedule, Snaith-Hamilton Pleasure Scale, Temporal Experience of Pleasure Scale, and cognitive tasks.
Clinical rating scales of mood, anxiety, and anhedonia
Time frame: Baseline, 230 min post-drug, and Days 1, 2, 3, 4, 7, 8, 10, 11, and 12, per Test Session.
Change from baseline on item 10 (suicidality) of the Montgomery-Asberg Depression Rating Scale and total score on the Columbia Suicide Severity Rating Scale and the Scale for Suicide Ideation.
Clinical rating scales of depression and suicidality
Time frame: Baseline, 230 min post-drug, and Days 1, 2, 3, 4, 7, 8, 10, 11, and 12, per Test Session.
Proportion of participants achieving response (defined as a >/=50% reduction from baseline in Montgomery-Asberg Depression Rating Scale total score)
Clinical rating scale of depression
Time frame: Baseline, 230 min post-drug, and Days 1, 2, 3, 4, 7, 8, 10, 11, and 12, per Test Session.
Proportion of participants in remission (defined as Montgomery-Asberg Depression Rating Scale total score =10)
Clinical rating scale of depression
Time frame: Baseline, 230 min post-drug, and Days 1, 2, 3, 4, 7, 8, 10, 11, and 12, per Test Session.
Change from baseline on Montgomery-Asberg Depression Rating Scale total scores
Clinical rating scale of depression
Time frame: Baseline, 230 min post-drug, and Days 1, 2, 3, 4, 7, 8, 10, 11, and 12, per Test Session.
Pain thresholds and tolerance during quantitative sensory testing.
Measures assess acute pain in response to noxious stimuli.
Time frame: Baseline and Days 1, 4, 8, and 11, per Test Session.
Pain thresholds and tolerance during quantitative sensory testing while undergoing fMRI.
fMRI procedures to evaluate dose-dependent effects of HNK on analgesia.
Time frame: Days 4 and 11, per Test Session
Plan to share: Yes — Clinical and demographic and biomarker participant data collected during the trial, after deidentification.
Supporting information: Statistical analysis plan
Time frame: Starting within 1 year of completion of the study.
Access criteria: Branch Chief will review requests and access will need to be approved by the NIMH/DIRP SD and OCD NIMH and the NIH IRB.
Started Nov 2024 (actual). Primary completion is estimated for Jul 2027, 31 months after the start.
Of 50 phase 2 interventional studies under Depressive Disorder, Treatment-Resistant, half reached primary completion within 31 months of starting (the median), counting those still running; a quarter within 17 and three quarters within 41. This study's planned 31 months is close to that.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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