Otsuka Pharmaceutical Co., Ltd. (Otsuka) announces topline outcomes from a phase II clinical trial that evaluated the safety and efficacy of brexpiprazole for the treatment of patients with borderline personality disorder (BPD). The trial did not meet the primary endpoint, change from baseline in the Zanarini Rating Scale^* for BPD.

The randomized, double-blind, placebo-controlled phase II study was initiated jointly with H. Lundbeck A/S (Lundbeck) in 2019. It was designed to assess the efficacy, safety and tolerability of flexible doses (2 to 3 mg) of brexpiprazole as monotherapy in adult subjects with borderline personality disorder (BPD) . The study consisted of a 12-week, double-blind treatment period and a 21-day follow-up after the last dose. A total of 324 participants were randomized to treatment in the study. (NCT04100096）

The study did not show statistically significant separation from placebo at the predefined time point for the primary endpoint, change from baseline in the Zanarini Rating Scale for BPD. However, statistically larger numeric improvements greater than placebo were observed at other time points in the study.

The observed safety and tolerability profile for patients with borderline personality disorder was consistent with the safety and tolerability profile observed for patients treated with brexpiprazole in other indications.

Otsuka and Ludbeck plan to submit the detailed trial outcomes for scientific publication at a future date.

• A clinician-administered interview to assess severity and change in BPD symptoms. Nine criteria for BPD are rated on a five-point rating scale of 0 to 4, yielding a total score of 0 to 36.