Minocycline as Adjunctive Treatment for Treatment Resistant Depression
Status:
Recruiting
Trial end date:
2022-08-01
Target enrollment:
Participant gender:
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 at least two adequate trials of antidepressant treatment. 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 (HAMD-17), Clinical Global
Impression scale (CGI), Patient Health Questionnaire (PHQ-9), and the Generalized Anxiety
Disorder scale (GAD-7) at each study visit (screening, 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.