Efficacy and safety of Gyejibokryeong-hwan (GBH) in major depressive disorder: study protocol for multicentre randomised controlled trial

Background: Gyejibokryeong-hwan (GBH) is an herbal medicine composed of five herbs. It has been widely used to treat gynaecological diseases in traditional East Asian medicine. Recent animal studies suggest antidepressant effects of GBH. In this trial, we explore the efficacy and safety of GBH in patients with major depressive disorder and to identify the optimal dose for the next phase III trial. Methods: This trial will enrol 126 patients diagnosed with major depressive disorder and not treated with antidepressants. Participants will be randomised to receive a high or a low dose of GBH or placebo granules. The study drugs will be administered three times a day, for 8 weeks. The 17-item Hamilton Depression Rating Scale (HDRS) will be used to measure the severity of depressive symptoms at weeks 2, 4, 6, 8, and 12. The primary efficacy endpoint is the change from baseline in HDRS-17 total score post-treatment at week 8. Analysis of covariance will be based on the baseline HDRS-17 total score and site as the covariates. Safety assessment will be based on the frequency of adverse events. The severity and causality of the study drug will be assessed. Discussion: This study is designed to evaluate the efficacy and safety of GBH granules compared with placebo in patients with major depressive disorder. Trial registration: Clinical Research Information Service KCT0004417. Registered on November 1, 2019 (prospective registration).