A Study of Safety and Effectiveness of Ustekinumab (CNTO 1275) in Patients With Moderate to Severe Plaque-type Psoriasis (PHOENIX1)

• Psoriasis Area-and-severity Index (PASI) 75% Improvement From Baseline at Week 12. [ Time Frame: Week 12 ] [ Designated as safety issue: No ]
  The number of participants achieving at least 75% improvement from baseline in Psoriasis Area and Severity Index (PASI) (0 [best] - 72 [worst]) at Week 12. This is a test of how bad a person's psoriasis is. The combination of redness, scaling, and thickness, as well as overall body involvement determine the PASI score.
  
  

• Number of Participants Who Achieved a Physician Global Assessment (PGA) Score of Cleared (0) or Minimal (1) at Week 12 [ Time Frame: Week 12 ] [ Designated as safety issue: No ]
  The PGA is used to determine the participant's psoriasis lesions overall at a given time point. Overall lesions will be graded as : (0) = cleared, (1) = minimal, (2) = mild, (3) = moderate, (4) = marked, and (5) = severe for induration, erythema, and scaling. The sum of the 3 scales will be divided by 3 to obtain a final PGA score ranging from 0 [best] to 5 [worst].
  
  
• Change From Baseline in Dermatology Life Quality Index (DLQI) at Week 12 [ Time Frame: Baseline (Week 0), Week 12 ] [ Designated as safety issue: No ]
  Change from baseline in Dermatology Life Quality Index (DLQI) from baseline at Week 12. This DLQI is a 10-item questionnaire, that in addition to evaluating overall quality of life, can be used to assess 6 different aspects that may affect quality of life: symptoms and feelings, daily activities, leisure, work or school performance, personal relationships, and treatment. Scores range from 0 (no impairment in quality of life) to 30 (most impairment in quality of life).
  
  
• Psoriasis Area and Severity Index (PASI) 75 Responders at Week 52 [ Time Frame: Week 52 ] [ Designated as safety issue: No ]
  The number of participants achieving at least 75% improvement from baseline in Psoriasis Area and Severity Index (PASI) (0 [best] - 72 [worst]) at Week 52 in participants randomly assigned to a treatment group at Week 40. This is a test of how bad a person's psoriasis is. The combination of redness, scaling, and thickness, as well as overall body involvement determine the PASI score.
  
  

This is a randomized (patients are assigned to different treatments based on chance), double blind (neither the patient nor the physician knows whether medication or placebo [an inactive substance that is compared with a medication to test whether the medication has a real effect in a clinical study] is being taken, or at what dosage), parallel-group (each group of patients are treated at the same time), multicenter study to determine the effectiveness and safety of two different doses of ustekinumab administered subcutaneously (under the skin) as compared with placebo in patients with moderate to severe plaque-type psoriasis (the most common type of psoriasis). 766 patients will be randomized to Group 1 (ustekinumab 45 mg), Group 2 (ustekinumab 90 mg) and Group 3 (placebo) at Week 0. The study was designed to evaluate the effectiveness and safety of 2 dose regimens of ustekinumab: (1) 45 mg at Weeks 0 and 4 followed by 45 mg every 12 weeks maintenance therapy (treatment designed to help the original primary treatment succeed) and (2) 90 mg at Weeks 0 and 4 followed by 90 mg every 12 weeks maintenance therapy. The study will consist of 4 periods: (1) Placebo-controlled portion of study [Week 0 to Week 12] during which the safety and effectiveness of 2 doses (45mg and 90mg) of ustekinumab will be compared to placebo; (2) Placebo crossover and active treatment portion of study [Week 12 to Week 40] during which patients randomized to receive placebo at Week 0 will crossover to receive ustekinumab, and all patients will receive active treatment; (3) Randomized withdrawal portion of study [beginning at Week 40] during which patients who received ustekinumab [45mg or 90mg every 12 weeks] at Week 0 and are responding to it, will be randomized either to placebo or continued maintenance therapy with ustekinumab; and (4) Long-term extension [from Week 52 to Week 264 (ie, 5 years)] period during which the safety and effectiveness of ustekinumab long-term use will be evaluated in patients.