A Study of Guselkumab in the Treatment of Participants With Moderate to Severe Plaque-Type Psoriasis With Randomized Withdrawal and Retreatment

The purpose of this study is to evaluate the efficacy, safety, and tolerability of guselkumab (CNTO 1959) in the treatment of participants with moderate to severe plaque-type psoriasis (scaly skin rash).

This is a randomized (assignment of study drug by chance), double-blind (neither the participant or study staff will know the identity of study drugs), placebo- (inactive substance identical in appearance to study drug) and active-comparator-controlled (use of an approved drug to compare with study drug) study of guselkumab. The active comparator study drug is adalimumab, an approved drug for the treatment of moderate to severe plaque psoriasis. Participants who satisfy all inclusion and exclusion criteria will be randomly assigned in a 2:1:1 ratio to one of three treatment groups (arms): Group I (guselkumab 100 mg dose regimen), Group II (placebo then crossover to guselkumab at Week 16), or Group III (adalimumab at standard psoriasis dosing). From Week 28 up to Week 76, treatment for all participants will be based on their level of response. All participants will receive guselkumab every 8 weeks from Week 76 through Week 252 with a final safety follow-up visit at Week 264 (open label treatment period). The end of the study is defined as the time the last participant completes the Week 264 visit. The total duration of the study will be approximately 268 weeks (includes a 4-week screening period). Participants will be monitored for safety throughout the study.