Efficacy and safety of adjunctive brexpiprazole 2 mg in major depressive disorder: a phase 3, randomized, placebo-controlled study in patients with inadequate response to antidepressants.

OBJECTIVE To assess the efficacy, tolerability, and safety of brexpiprazole as adjunctive therapy to antidepressant treatments (ADTs) in adults with major depressive disorder (as defined by DSM-IV-TR criteria) and inadequate response to ADTs. METHOD Patients with historical inadequate response to 1-3 ADTs were enrolled. All patients entered a prospective 8-week phase on physician-determined, open-label ADT. Those with inadequate response were randomized to ADT + brexpiprazole 2 mg/d or ADT + placebo for 6 weeks. The study was conducted between July 2011 and May 2013. The primary efficacy end point was change from baseline to week 6 in Montgomery-Asberg Depression Rating Scale (MADRS) total score. The key secondary end point was change from baseline to week 6 in Sheehan Disability Scale (SDS) mean score. The efficacy population comprised all patients who had ≥ 1 dose of study drug in the double-blind phase and both baseline and ≥ 1 postrandomization MADRS scores. The efficacy population per final protocol included patients from the efficacy population who met amended randomization criteria of inadequate response throughout prospective treatment. RESULTS Brexpiprazole (n = 175) reduced mean MADRS total score versus placebo (n = 178) at week 6 in the efficacy population per final protocol (-8.36 vs -5.15, P = .0002). Brexpiprazole improved SDS mean score versus placebo (-1.35 vs -0.89, P = .0349). The most common treatment-related adverse events were weight gain (brexpiprazole, 8.0%; placebo, 3.1%) and akathisia (7.4% vs 1.0%). CONCLUSIONS Adjunctive brexpiprazole therapy demonstrated efficacy and was well tolerated in patients with major depressive disorder and inadequate response to ADTs. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT01360645.