Comparative Efficacy of Dopamine Partial Agonists by Doses for Treatment-Resistant Depression

BackgroundThe augmentative antidepressant effects of dopamine partial agonists (aripiprazole, brexpiprazole, and cariprazine) for treatment-resistant depression have been compared in a previous network meta-analysis. However, the comparative efficacy of the dose-responses of these drugs remains unclear. Therefore, we aimed to estimate the dose-response relationships and compare the effects of each dopamine partial agonist doses.MethodsWe conducted a systematic review of the Cochrane Library, PubMed, CINHAL, and ClinicalTrials.gov databases until January 1, 2023. Double-blind, randomized, placebo-controlled trials evaluating aripiprazole, brexpiprazole, and cariprazine for treatment-resistant depression were included. A random-effect dose-response model-based network meta-analysis was conducted. This study was registered in PROSPERO (CRD42023393035).ResultsThe maximum effective doses were 5.5 mg for aripiprazole, 1.6 mg for brexpiprazole, and 1.5 mg for cariprazine, respectively. Although all doses of the 3 drugs were significantly more effective than placebo, aripiprazole ranging from 5.5 to 12.5 mg was significantly more effective than brexpiprazole 0.5 mg and cariprazine ranging from 0.5 to 1 mg. Moreover, aripiprazole ranging from 7.5 to 12.5 mg was significantly more effective than all doses of cariprazine. In addition, brexpiprazole ranging from 1 to 3 mg was significantly more effective than cariprazine 0.5 mg and brexpiprazole ranging from 1.6 to 2.5 mg was significantly superior to cariprazine 1 mg. There were no doses at which brexpiprazole overcame aripiprazole, and cariprazine overcame aripiprazole or brexpiprazole.ConclusionsAripiprazole, brexpiprazole, and cariprazine may be effective in treatment-resistant depression in that order, with the maximum effective doses at 5.5 mg, 1.6 mg, and 1.5 mg, respectively.