An Efficacy Study of Paliperidone for the Prevention of Relapse in Patients With Schizophrenia

• Time to relapse [ Time Frame: Up to 74 weeks after the last patient is randomized ] [ Designated as safety issue: No ]
  A relapse is defined as any one of the following: 1. involuntary or voluntary psychiatric hospitalization 2. deliberate self-injury or violent behavior; 3. Suicidal or homicidal ideation and clinically significant aggressive behavior; 4. 25% increase in PANSS total score for 2 consecutive assessments for patients who score >40 at randomization, or a 10-point increase for patients who scored ≤40 at randomization; 5. increase for 2 consecutive assessments in PANSS items (P1, P2, P3, P6, P7 or G8) to ≥5 for patients who scored ≤3 at randomization, or to ≥6 for patients with initial score of 4.
  
  

• Positive and Negative Syndrome (PANSS) Scale [ Time Frame: Up to 74 weeks after the last patient is randomized ] [ Designated as safety issue: No ]
  PANSS is a 30-item scale which provides a total score (sum of the scores of all 30 items) and scores for 3 subscales, the positive subscale (7 items), negative subscale (7 items), and the general psychopathology subscale (16 items).
  
  
• Clinical global impression - severity (CGI-S) Scale [ Time Frame: Up to 74 weeks after the last patient is randomized ] [ Designated as safety issue: No ]
  The CGI-S rating scale is used to rate the severity of a patients condition on a 7-point scale ranging from 1 (normal, not at all ill) to 7 (among the most extremely ill patients).
  
  
• Personal and social performance (PSP) Scale [ Time Frame: Up to 74 weeks after the last patient is randomized ] [ Designated as safety issue: No ]
  The PSP scale assesses the degree of difficulty a patient exhibits over a 1-month period within 4 domains of behavior: socially useful activities, personal and social relationships, self-care, and disturbing and aggressive behavior. The score ranges from 1 to 100, divided into 10 equal intervals to rate the degree of difficulty (i, absent, to vi, very severe) in each of the 4 domains.
  
  
• Sleep visual analog scale (Sleep VAS) [ Time Frame: Up to 74 weeks after the last patient is randomized ] [ Designated as safety issue: No ]
  This scale assess quality of sleep and daytime drowsiness by placing marks on lines to represent how well they had slept in the previous 7 nights (very badly to very well) and how often they had felt drowsy in the past 7 days (not at all to all the time).
  
  
• Number of patients with adverse events [ Time Frame: Up to 74 or 98 weeks after the last patient is randomized ] [ Designated as safety issue: No ]
  

This is a double-blind (neither physician nor patient knows the name of the assigned drug), randomized (patients are assigned to treatment by a chance), placebo-controlled, parallel-group study of paliperidone ER tablets. The study will consists of 6 phases: 14 days of screening phase, 8 weeks of open-label run-in phase (patients will be flexibly dosed with paliperidone ER once daily in a dose range of 3 mg to 12 mg), 6 weeks of stabilization phase (patients will continue to receive the fixed dose of paliperidone ER), double-blind (DB) phase of various length (patients will be randomly assigned in a 1:1 ratio to receive either paliperidone ER or placebo and this phase will be completed after 86 relapse events are observed or if the study is positive at the interim analysis), 6 months of open-label extension (patients who experience a relapse event or who remain relapse free for the entire duration of the double-blind Phase and patients who are enrolled at the time the study is terminated, will be eligible for this phase. All patients will be treated with paliperidone ER and safety and tolerability information will be collected during this phase) phase and 6 months of follow-up phase (patients who withdraw during the DB phase for any reason other than relapse will be followed for 6 months or until they experience a relapse). Patients safety will be monitored throughout the study.