A Study of Ustekinumab to Evaluate a "Subject-tailored" Maintenance Dosing Approach in Subjects With Moderate-to-Severe Plaque Psoriasis

In this study, a proportion of subjects will receive study agent at its recommended dose and
interval (45mg for subjects less than or equal to 100kg, or 90mg for subjects greater than
100kg; every 12 weeks after 2 starter doses at Weeks 0 and 4). The majority of subjects will
have the opportunity to receive study agent less frequently during the randomization period
depending on the subject's response. The study consists of a 4-week screening period; a
28-week open-label run-in period; a double-blind treatment period from Week 28 to Week 104;
a 12 week post-treatment period; and a 20-week safety follow-up. Participants will be
randomized for the double blind period into one of two study groups. Group 1 participants
will receive an injection of the study medication at a 12 week dosing interval. Group 2
participants will undergo a placebo withdrawal and may receive study agents at an extended
interval greater than 12 weeks. During the double-blind treatment period, subjects in Groups
1 and 2 will receive placebo as necessary to maintain the blind.

Key Eligibility Criteria

- Male or female

- Have had a diagnosis of plaque-type psoriasis at least 6 months prior to the first
administration of study agent (subjects with concurrent psoriatic arthritis may be
enrolled).

- Have plaque-type psoriasis covering at least 10% of their total BSA at screening and
at the time of the first administration of study agent.

- Have a PGA score of ≥ 3 at screening and at the time of the first administration of
study agent.