A multi-center, open-label, parallel-group, randomized, flexible dose study to evaluate the safety and tolerability of switching from existing atypical antipsychotics to bifeprunox in subjects with schizophrenia or schizoaffective disorder.

INTERVENTION: Product Name: bifeprunox Product Code: DU 127090 Pharmaceutical Form: Tablet INN or Proposed INN: bifeprunox CAS Number: 350992‐13‐1 Current Sponsor code: DU 127090 Other descriptive name: potent antipsychotic agent Concentration unit: mg milligram(s) Concentration type: up to Concentration number: 30‐mg/day INN or Proposed INN: bifeprunox CAS Number: 350992‐13‐1 Current Sponsor code: DU 127090 Other descriptive name: potent antipsychotic agent Concentration unit: mg milligram(s) Concentration type: equal Concentration number: 20‐ INN or Proposed INN: bifeprunox CAS Number: 350992‐13‐1 Current Sponsor code: DU 127090 Other descriptive name: potent antipsychotic agent Concentration unit: mg milligram(s) Concentration type: equal Concentration number: 10‐ INN or Proposed INN: bifeprunox CAS Number: 350992‐13‐1 Current Sponsor code: DU 127090 Other descriptive name: potent antipsychotic agent Concentration unit: mg milligram(s) Concentration type: equal Concentration number: 5‐ INN or Proposed INN: bifeprunox CAS Number: 350992‐13‐1 Current Sponsor code: DU 127090 Other descriptive name: potent antipsychotic agent Concentration unit: mg milligram(s) Concentration type: equal Concentration number: 2‐ INN or Proposed INN: bifeprunox CAS Number: 350992‐13‐1 Current Sponsor code: DU 127090 Other descriptive name: potent antipsychotic agent Concentration unit: mg milligram(s) Concentration type: equal Concentration number: 1‐ INN or Proposed INN: bifeprunox CAS Number: 350992‐13‐1 Current Sponsor code: DU 127090 Other descriptive name: potent antipsychotic agent Concentration unit: mg milligram(s) Concentration type: equal Concentration number: 0.5‐ INN or Proposed INN: bifeprunox CAS Number: 350992‐13‐1 Current Sponsor code: DU 127090 Other descriptive name: potent antipsychotic agent Concentration unit: mg milligram(s) Concentration type: equal Concentration number: 0.25‐ Product Name: bifeprunox Product Code: DU 127090 Pharmaceutical Form: Capsule* INN or Proposed INN: CONDITION: schizophrenia ; MedDRA version: 8.1 Level: LLT Classification code 10039626 Term: Schizophrenia PRIMARY OUTCOME: Main Objective: The primary objective of the 4‐week core study is to evaluate the safety and tolerability of switching subjects with schizophrenia or schizoaffective disorder from their existing atypical antipsychotic medication to bifeprunox. Primary end point(s): The primary objective of the core study is to evaluate whether schizophrenic or schizoaffective subjects could be safely switched from existing atypical antipsychotic to bifeprunox. ; Subjects who are safely switched over are defined as those who complete the core study protocol with no worsening of two successive post‐baseline assessments on at least one of the followings: CGI‐S, exacerbation of EPS based on SAS total score or cardiovascular risk factors (body weight and fasting triglycerides) from baseline.; Safety and tolerability assessments include Simpson‐Angus Scale (SAS), Barnes Akathisia Scale (BAS) and Abnormal Involuntary Movement Scale (AIMS). Other safety assessments will include physical examination, weight and body mass index (BMI), waist circumference, thyroid function test, hemoglobin A1c (HbA1c), fasting glucose, fasting insulin, fasting lipid profile (LDL, VLDL, HDL, total cholesterol, triglycerides) and prolactin. Other routine safety assessments will consist of vital sign measurements to include systolic/diastolic blood pressure and pulse rate both after five minutes lying and after two minutes standing, and oral temperature, and resting ECG measurements, laboratory assessments including biochemistry, hematology and urinalysis. Adverse events monitoring and concomitant medication use will be recorded throughout the study. ; All raters (physician or certified personnel) for the study will be trained in the conduct of the efficacy and movement disorder scales. If at all possible, the same rater should rate each individual subject throughout the study.; Secondary Objective: The secondary objective of the core study is to compare the safety and tolerability of two different switching regimens.; The tertiary objective of the 22‐week extension is to determine the safety and efficacy response after switching to bifeprunox at 26 weeks.; INCLUSION CRITERIA: 1. The subject or subject’s authorized legal representative must understand the nature of the study and must provide written informed consent prior to conduct of any study procedures. 2. Each subject must be able to communicate with study personnel. 3. Current Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM‐IV TR) diagnosis of Schizophrenia (codes 295.10, 295.20, 295.30, 295.60, 295.90) or Schizoaffective Disorder (code 295.70) for whom a switch is indicated (inadequate clinical response, failure to respond partially to adequate treatment, present or persistent negative symptoms or cognitive impairment despite good compliance, or intolerable adverse side effects based on the Investigator’s judgment). 4. Subjects who do not have an exacerbation within the last eight weeks prior to baseline. 5. Subjects who are taking only one prior atypical antipsychotic medication (olanzapine, risperidone, quetiapine, ziprasidon