Efficacy outcomes from 3 clinical trials of edivoxetine as adjunctive treatment for patients with major depressive disorder who are partial responders to selective serotonin reuptake inhibitor treatment.

Abstract

Three studies examined whether edivoxetine (a highly selective norepinephrine reuptake inhibitor) had efficacy as adjunctive therapy for patients with major depressive disorder (DSM-IV-TR) who were partial responders to selective serotonin reuptake inhibitor (SSRI) treatment of at least 6 weeks' duration. Studies were 8-week randomized, placebo-controlled trials with a 3-week double-blind placebo lead-in phase, conducted from December 16, 2010, to October 21, 2013. Patients entered the double-blind adjunctive treatment phase if they met randomization criteria (< 25% improvement on Montgomery-Asberg Depression Rating Scale [MADRS] and MADRS total score ≥ 14); patients not randomized remained on adjunctive placebo. Study 1 compared fixed-dose edivoxetine (12 or 18 mg daily) + SSRI (N = 231 and N = 230, respectively) with placebo + SSRI (N = 240); study 2 compared flexible-dose edivoxetine (12-18 mg daily) + SSRI (N = 232) and fixed-dose edivoxetine (6 mg daily) + SSRI (N = 226) with placebo + SSRI (N = 231); and study 3 compared flexible-dose edivoxetine (12-18 mg daily) + SSRI (N = 230) with placebo + SSRI (N = 219). The primary outcome was mean change from randomization baseline to week 8 in MADRS total score, analyzed using repeated measures analysis. Each trial failed to meet the primary and most of the secondary objectives. The least-squares mean changes in MADRS total score were as follows-study 1: -8.5 (edivoxetine 12 mg + SSRI), -8.7 (edivoxetine 18 mg + SSRI), and -7.8 (placebo + SSRI); study 2: -9.4 (edivoxetine 12-18 mg + SSRI), -9.6 (edivoxetine 6 mg + SSRI), and -9.4 (placebo + SSRI); and study 3: -8.7 (edivoxetine 12-18 mg + SSRI) and -8.5 (placebo + SSRI). Adjunctive edivoxetine treatment for patients with major depressive disorder who were partial responders to SSRIs did not significantly improve efficacy outcomes. ClinicalTrials.gov identifiers: NCT01173601, NCT01187407, NCT01185340.