A Study to Evaluate Safety and Efficacy of Infliximab in Chinese Participants With Moderate to Severe Plaque-type Psoriasis

The purpose of this study is to determine the superiority and efficacy of infliximab induction therapy in chinese participants with moderate to severe plaque-type psoriasis (scaly skin rash) compared with placebo (an inactive substance that is compared with a drug to test whether the drug has a real effect in a clinical trial).

This is a double-blind (neither physician nor participant knows the treatment that the participant receives), multicenter (when more than one hospital or medical school team work on a medical research study) and placebo-controlled study of infliximab in participants with moderate to severe plaque-type psoriasis. All the eligible participants will be randomly assigned to infliximab and placebo groups. The infliximab group will receive 5 milligram per kilogram (mg/kg) infliximab infusions (a fluid or a medicine delivered into a vein by way of a needle) intravenously (into a vein) at Week 0, 2 and 6 in the induction treatment phase followed by maintenance regimen of the intervention every 8 weeks up to 26 weeks. Placebo infusions will also be given at Week 10, 12 and 16. The placebo group will receive placebo infusion at Week 0, 2, 6, 14 and 22. At Week 10, participants in placebo group will then receive infliximab induction therapy. Efficacy of the participants will primarily be evaluated by percentage of participants who achieve a Psoriasis Area and Severity Index 75 (PASI) response at Week 10. Participants' safety will be monitored throughout the study.

Eligibility Criteria:
Inclusion Criteria:

* The body weight should be less than or equal to 80 kilogram
* Participants who had a diagnosis of plaque-type psoriasis (scaly skin rash) greater than or equal to 6 months before Screening (participants with concurrent psoriatic arthritis \[joint pain\] may be enrolled)
* Participants who had plaque-type psoriasis covering greater than or equal to 10 percent of total body surface area, Psoriasis Area Severity Index (PASI) score greater than or equal to 12 at Screening and at the Baseline
* Participants who are candidates for systemic treatment of psoriasis
* Females of childbearing potential and all men must be using adequate birth control measures and agree to use these measures and should not become pregnant (carrying an unborn baby) or plan to become pregnant up to 6 months after receiving last infusion of study drug

Exclusion Criteria:

* Participants who have nonplaque forms of psoriasis ( for example, erythrodermic, guttate, or pustular), or have current drug-induced psoriasis (for example, a new onset of psoriasis or an exacerbation of psoriasis from beta blockers, calcium channel blockers, or lithium)
* Participants who are pregnant, nursing or planning to become pregnant within one year while enrolled in the study
* Participants who had previous treatment with infliximab
* Participants who have received agents targeted at reducing tumour necrosis factor or any biologic treatment within the previous 3 months
* Participants who have used any investigational drug within the previous 4 weeks or 5 times the half-life of the investigational agent, whichever is longer