A Multicenter, Open-Label Study to Evaluate the Long-term Safety and Efficacy of Adjunctive Brexpiprazole 2 mg Daily in Japanese Patients with Major Depressive Disorder.

Background and objective: Inadequate response to antidepressant monotherapy is common among patients with major depressive disorder (MDD). The efficacy and safety of adjunctive brexpiprazole 2 mg/day has recently been confirmed during the 6-week, randomized, placebo-controlled phase 2/3 (BLESS) study, which evaluated brexpiprazole at 1 mg/day and 2 mg/day versus placebo as adjunctive therapy to antidepressant therapies in 740 Japanese patients with MDD and an inadequate response to antidepressant monotherapy. This study evaluated the long-term safety and efficacy of adjunctive fixed-dose brexpiprazole 2 mg/day in Japanese patients with MDD.

Methods: An open-label, 52-week study enrolled rollover patients who completed the 6-week, double-blind, randomized, placebo-controlled phase 2/3 BLESS study (NCT03697603), and de novo patients aged ≥ 65 years. Patients were titrated to fixed-dose brexpiprazole 2 mg/day from Week 1. Safety assessments included treatment-emergent adverse events (TEAEs; primary outcome) and clinical and laboratory variables. Efficacy was assessed using the Montgomery-Åsberg Depression Rating Scale (MADRS), Clinical Global Impression-Improvement (CGI-I) scale, Hamilton Depression Rating Scale (HAM-D) 17-item total score, and Sheehan Disability Scale (SDS) score.

Results: In total, 247 patients [rollover, n = 216; de novo (previously unexposed), n = 31] were included in the safety/efficacy populations, and 138 (rollover, n = 132; de novo, n = 6; 55.9%) completed the study. Common TEAEs (incidence ≥ 10%) were weight gain [33.2% (n = 82)], akathisia [23.5% (n = 58)], nasopharyngitis [21.1% (n = 52)], and somnolence [10.5% (n = 26)]. TEAEs leading to treatment discontinuation occurred in 26.7% of patients receiving brexpiprazole and 58.1% of de novo patients. The mean (SD) increase in body weight from baseline to Week 52 [observed cases (OC)] was 4.2 (6.5) kg (n = 138); 44.5% (n = 110) had weight gain ≥ 7% at any postbaseline visit. There were no cases of tardive dyskinesia and no AEs related to suicide/suicide attempts. One death occurred (unknown cause), which was unrelated to study treatment. Improvements in the MADRS total score were observed from baseline over the course of the 52-week study [mean (SD) change at Week 52 (OC): - 7.3 (8.7)] for all patients receiving brexpiprazole. The overall MADRS response rate and remission rate in patients receiving brexpiprazole was 41.3% (n = 57) and 34.8% (n = 48), respectively, at Week 52 (OC). Improvements in CGI-S, HAM-D 17 item total score, and SDS mean scores were also observed from baseline over the 52-week study, with a mean (SD) change from baseline at Week 52 (OC) of - 0.8 (1.0), - 5.9 (6.3), and - 1.0 (2.2), respectively, indicating a sustained improvement in symptoms with long-term brexpiprazole treatment.

Conclusions: This is the first study to evaluate the safety profile of brexpiprazole 2 mg/day in Japanese patients with MDD, including older adults, which is similar to previous reports, with no new safety risks, and continued efficacy over 52 weeks.

Study registration: ClinicalTrials.gov (NCT03737474; registered on 29 July 2018).