Efficacy and safety of brexpiprazole for the treatment of acute schizophrenia in Japan: A 6‐week, randomized, double‐blind, placebo‐controlled study

AIM: This study aimed to evaluate the efficacy, safety, and tolerability of brexpiprazole compared to placebo in Japanese patients with acute schizophrenia (SCZ). METHODS: We conducted a 6-week, multicenter, double-blind, placebo-controlled, phase 2/3 study in Japan. Patients with acute SCZ were randomized (1:1:1:1) to receive brexpiprazole 1 mg, 2 mg, 4 mg, or placebo once a day. The primary endpoint was the change from baseline to week 6 in Positive and Negative Syndrome Scale (PANSS) total scores. RESULTS: In the 459 patients that were randomized, brexpiprazole 2 mg showed a significant improvement versus placebo (treatment difference: -7.32, P = 0.0124), although brexpiprazole 4 mg showed numerical improvements (treatment difference: -3.86, P = 0.1959), and brexpiprazole 1 mg showed only minimal change (treatment difference: -0.63, P = 0.8330). Treatment-emergent adverse events with an incidence of ≥5% and ≥2 times the rate of placebo in the brexpiprazole groups were vomiting, elevated blood prolactin, diarrhea, nausea, and dental caries. Most treatment-emergent adverse events were mild or moderate in severity. There were no clinically significant changes in electrocardiogram parameters, bodyweight, laboratory values, or vital signs in the brexpiprazole groups. CONCLUSION: Brexpiprazole was efficacious and well tolerated in Japanese adult patients with acute SCZ.