Efficacy and Safety of ABT-874 in Subjects With Moderate to Severe Chronic Plaque Psoriasis

Inclusion Criteria: * Subject was age 18 or older and in good health (Investigator discretion) with a recent stable medical history. * Subject had a clinical diagnosis of psoriasis for at least 6 months, and had moderate to severe plaque psoriasis Exclusion Criteria: * Subject had previously received systemic or biologic anti-IL-12 therapy * Subject cannot discontinue systemic therapies and/or topical therapies for the treatment of psoriasis and cannot avoid UVB or PUVA phototherapy * Subject is taking or requires oral or injectable corticosteroids * Subject considered by the investigator, for any reason, to be an unsuitable candidate for the study * Female subject who is pregnant or breast-feeding or considering becoming pregnant