Exploring Clinical Subgroups of Participants with Major Depressive Disorder that may Benefit from Adjunctive Minocycline Treatment

Objective@#To explore illness-related factors in patients with major depressive disorder (MDD) recipients of adjunctive minocycline (200 mg/day) treatment. The analysis included participants experiencing MDD from a 12-week, double blind, placebo-controlled, randomized clinical trial (RCT). @*Methods@#This is a sub-analysis of a RCT of all 71 participants who took part in the trial. The impact of illness chronicity (illness duration and number of depressive episodes), systemic illness (endocrine, cardiovascular and obesity), adverse effects and minocycline were evaluated as change from baseline to endpoint (12-week) using ANCOVA. @*Results@#There was a consistent but statistically non-significant trend on all outcomes in favour of the use of adjunctive minocycline for participants without systemic illness, less illness chronicity, and fewer adverse effects. @*Conclusion@#Understanding the relationship between MDD and illness chronicity, comorbid systemic illness, and adverse effects, can potentially better characterise those individuals who are more likely to respond to adjunctive anti-inflammatory medications.

Protocol and Rationale-The Efficacy of Minocycline as an Adjunctive Treatment for Major Depressive Disorder: A Double Blind, Randomised, Placebo Controlled Trial

While current pharmacotherapies are efficacious, there remain a clear shortfall between symptom remission and functional recovery. With the explosion in our understanding of the biology of these disorders, the time is ripe for the investigation of novel therapies. Recently depression is conceptualized as an immune-inflammatory and nitro-oxidative stress related disorder. Minocycline is a tetracycline antibiotic that has anti-inflammatory, pro-oxidant, glutamatergic, neurotrophic and neuroprotective properties that make it a viable target to explore as a new therapy. This double blind, randomised, placebo controlled adjunctive trial will investigate the benefits of 200 mg/day of minocycline treatment, in addition to any usual treatment, as an adjunctive treatment for moderate-severe major depressive disorder. Sixty adults are being randomised to 12 weeks of treatment (with a 4 week follow-up post-discontinuation). The primary outcome measure for the study is mean change on the Montgomery-Asberg Depression Rating Scale (MADRS), with secondary outcomes including the Social and Occupational Functioning Assessment Scale (SOFAS), Clinical Global Impressions (CGI), Hamilton Rating Scale for Anxiety (HAM-A), Patient Global Impression (PGI), Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q) and Range of Impaired Functioning Tool (LIFE-RIFT). Biomarker analyses will also be conducted at baseline and week 12. The study has the potential to provide new treatment targets, both by showing efficacy with a new class of 'antidepressant' but also through the analysis of biomarkers that may further inform our understanding of the pathophysiology of unipolar depression.