• The proportion of patients who achieved >=75% improvement in Psoriasis Area and Severity Index (PASI) at Week 12. [ Time Frame: At Week 12 ] [ Designated as safety issue: No ]
  

• The proportion of patients judged as [ Time Frame: At Week 12 ] [ Designated as safety issue: No ]
  

This is a multicenter, randomized (patients assigned study drug by chance), double-blind (neither the patient nor the physician knows the assigned medication name), placebo-controlled, parallel-group comparison study. This study has been planned to examine the effectiveness and safety of CNTO 1275 in Japanese patients with moderate to severe plaque type psoriasis in subcutaneous administration of the drug using placebo as a control. In the study, a clinical dose of the drug will be determined based on the obtained effectiveness and safety and it will be confirmed that similar therapeutic effect and safety can be obtained in this study compared to other phase III studies. The patients will be randomly assigned to one of three treatment groups. Since the double-blind method is employed in this study, two prefilled syringes per dosing will be subcutaneously administered to patients during the treatment period. At 12 weeks and later in the active-drug treatment period, CNTO 1275 will be administered to all patients. [Placebo-controlled treatment period <Weeks 0-12>]: 45-mg group: subcutaneous (s.c.) treatment with CNTO 1275 45 mg (0.5 mL) and placebo (1.0 mL) at Weeks 0 and 4. 90-mg group: s.c. treatment with CNTO 1275 90 mg (1.0 mL) and placebo (0.5 mL)at Weeks 0 and 4. [Active-drug treatment period <Weeks 12-64>]: 45-mg group: s.c. treatment with placebo (0.5 mL and 1.0 mL) at Week 12, followed by s.c. treatment with CNTO 1275 45 mg (0.5 mL) and placebo (1.0 mL) at Week 16. Subsequently, s.c. treatment with CNTO 1275 45 mg (0.5 mL) and placebo (1.0 mL) every 12 weeks up to Week 52. 90-mg group: s.c. treatment with placebo (0.5 mL and 1.0 mL) at Week 12, followed by s.c. treatment with CNTO 1275 90 mg (1.0 mL) and placebo (0.5 mL) at Week 16.

Subsequently, s.c. treatment with CNTO 1275 90 mg (1.0 mL) and placebo (0.5 mL) every 12 weeks up to Week 52.

Placebo group: At Weeks 12 and 16, s.c. treatment with CNTO 1275 and placebo in patients divided into the following 2 groups. Subsequently, s.c. treatment with CNTO 1275 at the same dose and placebo every 12 weeks up to Week 52. Placebo group A: CNTO 1275 45 mg (0.5 mL) and placebo (1.0 mL). Placebo group B: CNTO 1275 90 mg (1.0 mL) and placebo (0.5 mL). The sorting to the Placebo group A or Placebo group B will be already determined at the time of allocation conducted at registration. In addition the pharmacokinetics (including the measurement of serum anti-CNTO 1275 antibodies) will be assessed. The investigator will handle any untoward medical event (including abnormal changes in laboratory data) that occurred in patients from after informed consent to the end of follow-up period as an adverse event, and conduct the safety assessment. The information of adverse events (any untoward medical event that occurs in subjects administered an investigational product, and it does not necessarily indicate only events with a clear causal relationship with the relevant investigational product), adverse reactions any deleterious and unintended reactions (including laboratory test abnormalities) and injection site reaction］will be collected for safety assessments.

Placebo (PLA)-controlled period: 1) CNTO 45 mg: CNTO 45 mg (0.5mL) + PLA (1.0ml), 2) CNTO 90 mg: CNTO 90 mg (1.0mL) + PLA (0.5ml), 3) PLA: PLA (0.5 and 1.0 ml) Active period:1) CNTO 45 mg: PLA (0.5 + 1.0mL) at Week 12, CNTO 45 mg at Week16, CNTO 45 mg + PLA (1.0) every 12 weeks up to 52 weeks, 2)CNTO 90 mg: PLA(0.5+1.0mL) at Week12, CNTO 95 mg at Week16, CNTO 90 mg + PLA (1.0) every 12 weeks up to 52 weeks, 3) PLA-a: CNTO 45 mg + PLA (1.0ml), 4) PLA-b: CNTO 90 mg + PLA (0.5ml).