Efficacy of Adjunctive Brexpiprazole in Patients With Major Depressive Disorder and Partial Response to Antidepressant Treatment: a Post Hoc Analysis of Three Randomized Studies

Abstract: Background: Approximately 50% of patients with major depressive disorder (MDD) have unresolved symptoms of depression on antidepressant treatment (ADT), which are associated with worse prognosis and greater functional burden. This pooled analysis investigated the efficacy of adjunctive brexpiprazole in patients with MDD and partial response to ADT, defined as 25–50% improvement from baseline in Montgomery–Åsberg Depression Rating Scale (MADRS) Total score. Methods: Data were included from three similarly designed, short-term, randomized, double-blind, placebo-controlled studies of adjunctive brexpiprazole in adults with MDD and inadequate response to ADTs (i.e., persistent symptoms without substantial improvement) (NCT01360645, NCT02196506, NCT01727726). The studies comprised an 8–10-week prospective treatment phase during which patients were assessed for partial response to ADT + placebo, followed by a 6-week randomized phase during which patients received either ADT + placebo or ADT + brexpiprazole. Efficacy was assessed by change in MADRS Total score during the randomized treatment phase. Results: In patients with partial response to ADT, adjunctive brexpiprazole was associated with greater improvement in depressive symptoms than adjunctive placebo: the least squares mean difference in change from baseline to Week 6 in MADRS Total score for ADT + brexpiprazole 2 mg (n=122) versus ADT + placebo (n=166) was -1.42 (95% confidence interval: -2.71 to -0.14; p