GSK372475 is a triple reuptake inhibitor with approximately equipotent inhibition of serotonin, norepinephrine, and dopamine transporters. Two randomized, placebo- and active-controlled, double-blind studies examined the efficacy and safety of GSK372475 in outpatients (aged 18-64 years) with a diagnosis of major depressive episode associated with major depressive disorder (MDD). Patients were randomized 1:1:1 to placebo, GSK372475 (1-2 mg/d), or active control (Study 1: venlafaxine XR 150-225 mg/d; Study 2: paroxetine 20-30 mg/d). GSK372475 did not significantly differ from placebo on any of the key efficacy endpoints (six-item Bech scale, IDS-Clinician Rated, MADRS) in either study. Both active controls demonstrated significant antidepressant activity compared with placebo on both primary and secondary endpoints. The most common adverse effects (AEs) with GSK372475 were dry mouth, headache, insomnia, and nausea. AEs were more frequent for GSK372475 versus placebo for sleep, anxiety-related, gastrointestinal, and tachycardia events. Increases in mean change from baseline in heart rate and sitting blood pressure were greater for GSK372475 than observed for either placebo or active control groups. Completion rates were lower for GSK372475 (49%, 58%) compared with placebo (67%, 74%), venlafaxine XR (63%), or paroxetine (77%). GSK372475 was neither efficacious nor well tolerated in patients with MDD in two 10-week studies.
Trial registration: ClinicalTrials.gov NCT00420641 NCT00448058.