PANDORA(PAliperidoNe Extended Release(ER) DOsing & Clinical Response in Acute Schizophrenia)

The purpose of this open label, prospective, non-comparative study is to evaluate the flexible dose of paliperidone Extended Release (ER) and clinical response in the treatment of patients with schizophrenia

This clinical study is a 12-week multi-center, open-label, prospective, non-comparative study. This clinical study is composed of the screening period, 12-week acute treatment phase and 12-week extension phase (maintenance treatment) for the appropriate subjects (the patients who completed the 12-week acute treatment phase). The patients who completed the 12-week acute treatment phase can take part in the additional 12-week extension phase by signing the informed consent form.

The outcome of clinical study on effectiveness and safety of paliperidone has been obtained through the randomized(neither patient nor physician knows the assigned study frug medication name), placebo-controlled, double-blind(neither the patient nor the physician knows of the study drug medication name) , phase III study. Since the phase III clinical study is the study to allocate the patients randomly to the fixed dose groups from the beginning of the study to keep treating them with the pre-determined dose, it is difficult to provide the optimal dose data in consideration of diversity of individual patients. Due to the very strict inclusion/exclusion criteria, the patients participating in the phase III study may show different clinical characteristics from patients in clinical practice. In clinical practice, the optimal dose is decided at the time of the optimum treatment effectiveness and minimized adverse effects. Since the optimal dose is different from person to person, the data on the optimal dose levels and range by the patient's characteristic is required for the purpose of maximizing the treatment effectiveness and minimizing adverse effects for each patient. Most of the patients in the phase III clinical study were westerners. The Orientals accounted for 10% of the patients. In case of CNS(Central Nervous System) drugs, the Orientals have been often observed to have different dose levels and tolerance from the westerners in clinical practice and their metabolic enzyme activity is known to be different. Therefore, the study of Korean patients treated with variable doses of paliperidone ER has the primary objective of examining the proportion of the patients who are properly treated in each dose group and clarifying the characteristics of the patient groups which require either high-dose or low-dose drug.

This study will be conducted to examine the effectiveness and tolerance of each dose of paliperidone ER in schizophrenia patients. The primary objective of this study is to evaluate the effectiveness of paliperidone ER at week 12 of paliperidone ER treatment in the schizophrenia patients. The treatment effectiveness will be evaluated with the proportion of responders(Responder : the subject evaluated as "1. Very much improved" or "2. much improved" on the CGI-I(Clinical Global Impression - Improvement) Scale. The secondary objectives of this clinical study are as follows;(1)To examine the proportion of the subjects continuously treated with 6 mg/day regimen until week 12 in order to evaluate the effectiveness of paliperidone ER 6 mg/day (recommended dose); (2)To compare the treatment effectiveness of each dose by examining dose frequency and CGI-S and CGI-I score distribution by dose at week 12; (3)To evaluate the effectiveness for global function and individual/social function measured by Personal and Social Performance Scale (PSP) at week 12; (4)To examine the subject's attitude toward the drug measured by DAI (Drug Attitude Inventory); (5)To examine tolerance of paliperidone ER with the UKU(Udvalg for Kliniske Undersogelser) side effect rating scale, Vital signs, Laboratory test, ECG, Body weight, Waist circumference and hip circumference All the patients will orally take paliperidone ER 6 mg once daily during initial 2 weeks. thereafter, the study drug dose will be adjusted from paliperidone ER 3 mg/day to 12 mg/day for 12weeks.

Inclusion Criteria:

• Patients with CGI-S >= 4 points (moderately ill) at screening
• Childbearing potential women who consent to the consistent use of the acceptable contraception (oral contraceptive, contraceptive injection, intrauterine device, double barrier method and contraceptive patch)
• Patients who are capable of and willing to fill out the questionnaire for themselves
• Patients who are compliant with self-medication or can receive consistent help or support

Exclusion Criteria:

• Patients with the past history of neuroleptic malignant syndrome (NMS)
• Patients with Treatment Resistance history who have failed to be properly treated with more than two other kinds of antipsychotic agents (at least 4 weeks of the therapeutic dose administration)
• Patients with severe (pathologic or iatrogenic) gastrointestinal stenosis or patients who cannot swallow the drug whole (The study drug must not be chewed, divided, melted or grinded because it can impact the study drug release profile.)
• Patients who have been exposed to the study drug within one month before screening
• Patients with significant risk including suicide or aggressive behavior
• Patients with significant abnormal findings in biochemical, hematological and urine analyses which are clinically significant at the investigator's discretion