title: Efficacy and Safety of Bitopertin in Patients with Schizophrenia and Predominant Negative Symptoms: Subgroup Analysis of Japanese Patients from the Global Randomized Phase 2 Trial.
abstract: OBJECTIVE
  The aim of the present study was to perform a subgroup analysis of data from a phase II global, multi-center, randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of bitopertin, a glycine reuptake inhibitor that activates N-methyl-D-aspartate receptors by increasing the concentration of glycine in the synaptic cleft, in Japanese and non-Japanese patients with schizophrenia and predominant negative symptoms.
  
  
  METHODS
  Patients with schizophrenia and predominant negative symptoms on one or two antipsychotic drugs, including atypical antipsychotic drugs (olanzapine, risperidone, quetiapine, aripiprazole, and paliperidone) as the primary treatment, received bitopertin (10, 30, or 60 mg/day) or placebo once daily for 8 weeks as an add-on treatment. Efficacy was assessed using the Positive and Negative Syndrome Scale (PANSS) negative symptom factor score (NSFS).
  
  
  RESULTS
  The efficacy of bitopertin (10 mg and 30 mg) was similar between Japanese and non-Japanese patients. In the bitopertin 60-mg group, no difference from the placebo group was observed in Japanese or non-Japanese patients. The response to placebo was lower in Japanese patients, and there was a trend towards a greater difference in the change in PANSS NSFS between the placebo group and the 10-mg and 30-mg groups among Japanese patients. The safety profile of bitopertin was favorable in Japanese and non-Japanese patients.
  
  
  CONCLUSIONS
  According to this subgroup analysis from a global phase II study of bitopertin, there was no difference in terms of efficacy and safety between Japanese and non-Japanese patients.
authors.affiliation: Department of Psychiatry, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Hirayasu
authors.affiliation: Chugai Pharmaceutical Co., Ltd., Tokyo, Japan.
authors.forename: Shin-Ichi
authors.initials: SI
authors.lastname: Sato
authors.affiliation: Chugai Pharmaceutical Co., Ltd., Tokyo, Japan.
authors.forename: Norifumi
authors.initials: N
authors.lastname: Shuto
authors.affiliation: Chugai Pharmaceutical Co., Ltd., Tokyo, Japan.
authors.forename: Miwa
authors.initials: M
authors.lastname: Nakano
authors.affiliation: National Center of Neurology and Psychiatry, Tokyo, Japan.
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Higuchi
keywords: Bitopertin; Japan; Negative symptoms; Placebo response; Schizophrenia