Inflammation-stratified augmentation of vortioxetine with celecoxib: Results from a double-blind, randomized, placebo-controlled trial in major depressive disorder.

Low-grade inflammation is considered as a pathophysiological mechanism in a subtype of patients with major depressive disorder (MDD). Anti-inflammatory drugs have shown efficacy in treating MDD. However, it remains unclear how to identify suitable patients for anti-inflammatory treatment of depression. This study investigates the predictive value of pre-treatment high-sensitivity C-Reactive Protein (hsCRP) stratification on the outcome of celecoxib augmentation of vortioxetine. The PREDDICT study was conducted as a randomized, double-blind, placebo-controlled 6-week trial on augmentation of vortioxetine with celecoxib between December 2017 and April 2020 at the University of Adelaide (Australia). The present analysis focusses on the question of whether the pre-treatment hsCRP measurement and stratification of patients to depression with inflammation (hsCRP >3 mg/L) or without inflammation (hsCRP ≤3 mg/L) has an impact on the outcome of anti-inflammatory treatment with celecoxib. A total of n = 119 mostly treatment-resistant MDD patients with moderate to severe symptomatology were recruited in the trial. There was no effect of treatment group (celecoxib or placebo), pre-treatment hsCRP strata (with/without inflammation), or interaction between the two terms on treatment outcome. The results of the current analysis do not support the hypothesis that pre-treatment hsCRP level is predictive for response to anti-inflammatory treatment with celecoxib in MDD patients. Further research is needed to identify appropriate biomarkers for the prediction of anti-inflammatory treatment outcome in depression. CLINICAL TRIALS REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN12617000527369p. Registered on 11 April 2017, http://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12617000527369p.