Study of Paliperidone Palmitate 3 Month and 1 Month Formulations for the Treatment of Patients With Schizophrenia

• The percentage of patients who have not relapsed at the end of the 48-week Double-blind Phase. [ Time Frame: 48 weeks ] [ Designated as safety issue: No ]
  This will be determined based on the Kaplan-Meier 48-week cumulative estimate of survival (ie, percentage of subjects remaining relapse free).
  
  

• The changes from baseline in the neuropsychiatric symptoms of schizophrenia using the Positive and Negative Syndrome Scale (PANSS) during the Double-blind Phase. [ Time Frame: Baseline and 48 weeks ] [ Designated as safety issue: No ]
  The PANSS scale provides a total score (sum of the scores of all 30 items) and scores for 3 subscales, the positive subscale (7 items), the negative subscale (7 items), and the general psychopathology subscale (16 items). Each item is rated 1 (absent) to 7 (extreme).
  
  
• The changes from baseline in the patient's overall clinical condition measured by the change in Clinical Global Impression Severity (CGI-S) scale during the Double-blind Phase. [ Time Frame: Baseline and 48 weeks ] [ Designated as safety issue: No ]
  The CGI-S rating scale is used to rate the severity of a patient's overall clinical condition on a 7-point scale ranging from 1 (not ill) to 7 (extremely severe).
  
  
• The changes from baseline in the patient's functional status, measured by the Personal and Social Performance (PSP) scale during the Double-blind Phase. [ Time Frame: Baseline and 48 weeks ] [ Designated as safety issue: No ]
  The PSP scale measures personal and social functioning in the domains of: a) socially useful activities, b) personal and social relationships, c) self-care, and d) disturbing and aggressive behavior.
  
  
• The proportion of patients who meet criteria for symptomatic remission. [ Time Frame: Week 41 to 65 ] [ Designated as safety issue: No ]
  The proportion of patients with a simultaneous score of mild or less on all selected PANSS items (P1, P2, P3, N1, N4, N6, G5, and G9) maintained from Visit 14 (Week 41) to the end of the Double-blind Phase (Week 65).
  
  

This is a randomized (the study drug is assigned by chance), double blind (neither physician nor patient knows the treatment that the patient receives), parallel group (each group of patients will be treated at the same time), multicenter non-inferiority (the effect of the new treatment is not worse than that of the comparison treatment) study. The study consists of 3 phases: a screening/washout/tolerability phase (up to 21 days); a 17-week open-label (all people know the identity of the intervention) stabilization phase (referred to as the Open-label Phase) and a 48-week fixed dose, randomized, double-blind controlled phase (referred to as the Double-blind Phase). After completion of the Screening Phase, all patients will receive PP1M in the Open-label Phase. During this time, flexible dosing will occur at Weeks 5 and 9. At Week 13 patients are to receive the dose of PP1M that was administered at Week 9. Patients who are clinically stable at the end of the Open-label Phase will enter the Double-blind Phase and will be randomly assigned in a 1:1 ratio to receive fixed doses of PP3M or PP1M.