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Minocycline as Adjunctive Treatment for Treatment Resistant Depression

Minocycline as Adjunctive Treatment for Treatment Resistant Depression: a Double Blind, Placebo-controlled, Randomized Trial

Status
Completed
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03947827
Acronym
MINDEP2
Enrollment
76
Registered
2019-05-13
Start date
2020-02-01
Completion date
2025-01-07
Last updated
2026-03-27

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Treatment Resistant Depression

Keywords

Treatment Resistant Depression, Minocycline, Neuroinflammation, Microglial Activation, Biomarker

Brief summary

Major depressive disorder (MDD) is a leading cause of disability worldwide. Up to 50% of patients experience treatment resistant depression (TRD), which accounts for a vast majority of disease burden. Current medications for TRD have limited efficacy and can be associated with intolerable side effects. Therefore, there is a need for finding new treatment targets. Accumulating evidence suggests some patients with MDD including those with TRD, display brain inflammation. Thus, patients with TRD may benefit from medications that can reduce this inflammation. Minocycline is an antibiotic which can cross the blood-brain barrier and has effects on several systems implicated in depression. The principal investigator led the first pilot study of minocycline as an add-on treatment in TRD demonstrating that it led to a significant reduction in depressive symptoms compared to placebo and these findings require replication in a larger sample to confirm the efficacy and tolerability of this treatment approach. This study is a 12 week, double-blind, placebo-controlled trial of minocycline as add-on treatment for patients suffering from a major depressive episode who have failed to respond to antidepressant treatment, confirmed by the Structured Clinical Interview for DSM-5 (SCID-5) and the Antidepressant Treatment History Form (ATHF) at screening. After screening and randomization to the two parallel arms of the trial, 50 patients will receive minocycline added to treatment as usual (TAU) and 50 patients will receive placebo added to TAU. Clinical assessment will include the Hamilton Depression Rating Scale (HRSD-17), Clinical Global Impression scale (CGI), World Health Organization Quality of Life Short Form (WHOQOL-BREF), and Generalized Anxiety Disorder scale (GAD-7), administered at each study visit (baseline, week 2, 6, and 12). Side effects checklists will be undertaken at each visit. Minocycline will be started at 100 mg once daily and will be increased to 100 mg twice daily at two weeks. Secondary outcomes include inflammatory biomarkers measured at baseline, weeks 6 and 12. This trial will provide further evidence of minocycline's efficacy and acceptability as a treatment option for patients with TRD and provide insights into its mechanism of action.

Interventions

DRUGMinocycline

Participants will be randomized to receive either Minocycline or placebo added to standard oral antidepressants.

Sponsors

Centre for Addiction and Mental Health
Lead SponsorOTHER
The Physicians' Services Incorporated Foundation
CollaboratorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Masking description

Patients, their families, referring clinicians, lab workers and research assistants carrying out assessments will be concealed from allocation. Once randomized, pharmacy at the Centre for Addiction and Mental Health (CAMH) will be informed by email and deliver medication to the patient. An independent study psychiatrist will manage any clinical concerns and will be blind to treatment allocation. To assess the integrity of blinding procedures, participants and independent raters will be asked to complete a conventional guess form asking whether they believe participants received Minocycline or placebo as a treatment after the final ratings have been completed.

Eligibility

Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No

Inclusion criteria

1. Outpatients 2. Voluntary and competent to consent to treatment 3. DSM-5 diagnosis of non-psychotic MDD, single or recurrent, based on the SCID-5 4. Male or female aged between 18-80 5. Total score \> 3 on ATHF 6. Baseline HRSD-17 score \> 14 7. Able to adhere to study schedule 8. If female of childbearing potential, currently on a medically acceptable form of birth control (oral contraceptives, contraceptive injections, IUD, contraceptive patch, male partner sterilization, abstinence, or barrier methods plus spermicide) 9. Currently taking one of the following standard antidepressants: Escitalopram, Citalopram, Sertraline, Venlafaxine, Duloxetine, Mirtazapine or Bupropion 10. Been on same dose of all psychotropic medications for \> 4 weeks prior to enrolment

Exclusion criteria

1. DSM-5 substance use disorder within past 3 months, moderate or severe, based on SCID-5 2. Concomitant major unstable medical illness 3. Pregnancy or intent to become pregnant during study period 4. DSM-5 diagnosis of psychotic disorder, bipolar disorder, obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD) within last year 5. DSM-5 diagnosis of borderline personality disorder (BPD) 6. Possible or probable dementia 7. Prior or current intolerance or contraindication to tetracyclines 8. Abnormal readings in hematology, liver, or renal function tests 9. Have Myasthenia Gravis 10. Concomitant treatment with anticoagulants, diuretics, retinoids, ergot alkaloids, antacids containing aluminium/calcium/magnesium, bismuth and zinc salts, or quinapril

Design outcomes

Primary

MeasureTime frameDescription
Depressive symptoms12 weeksChanges from baseline to week 12 on the 17-item Hamilton Rating Scale for Depression (HRSD-17).

Secondary

MeasureTime frameDescription
Response rate12 weeksReduction of 50% or more in HRSD score from baseline to week 12
Remission rate12 weeksFinal HRSD score \< 8
Anxiety symptoms12 weeksChanges from baseline to week 12 in Generalized Anxiety Disorder scale (GAD-7)
Self-reported perception of quality of life12 weeksChanges from baseline to week 12 in World Health Organization Quality of Life Short Version (WHOQOL-BREF)
Clinician-rated illness severity12 weeksChanges from baseline to week 12 in Clinical Global Impression scale (CGI)

Countries

Canada

Contacts

PRINCIPAL_INVESTIGATORIshrat Husain, MBBS, MD(Res.)

CAMH

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Mar 28, 2026