This is a multicenter, dose-ranging study of CNTO 1959 in patients with moderate to severe plaque psoriasis. Patients who satisfy all inclusion and exclusion criteria will be assigned by chance to one of 7 treatment groups: a placebo group (a placebo is a treatment identical in appearance to CNTO 1959 but does not contain active drug), 1 of 5 dose groups for CNTO 1959, or adalimumab. Patients assigned to adalimumab will be dosed according to the labeled dosing for psoriasis. At Week 16, patients initially assigned to placebo will begin receiving CNTO 1959. Patients initially assigned to CNTO 1959 will continue to receive the same assigned dose level of study agent from Week 16 through Week 40. Patients receiving adalimumab will continue the labeled dosing regimen. All patients will be reassessed for clinical response every 4 weeks from Week 4 through Week 40. Patients will continue dosing through Week 40, with a subsequent efficacy and safety follow-up visit at Week 52. Patient safety will be monitored throughout the study.
