A Study to Determine the Optimal Dose of Tildrakizumab (SCH 900222/MK-3222) for the Treatment of Moderate-to-severe Chronic Plaque Psoriasis (P05495) (MK-3222-003)

Randomized, Double-Blinded, Placebo-Controlled, Parallel-Design, Dose-Range Finding Study of Subcutaneous Tildrakizumab (SCH 900222/MK-3222) in Subjects With Moderate-to-Severe Chronic Plaque Psoriasis (Study P05495)

This is a response-driven study of tildrakuzumab for the treatment of moderate to severe chronic plaque psoriasis. The primary study hypothesis is that one or more doses of tildrakizumab will be superior to placebo for the treatment of psoriasis.

Each participant will be enrolled in the trial for approximately 72-76 weeks. Each participant will receive assigned treatment at Weeks 0 and 4 in Part I. At Week 16, the dosage of treatment the patient is assigned to may be adjusted based on the Psoriasis Area and Severity Index (PASI) 75 response (responder vs non-responder). Participants will receive study medication once every 12 weeks during Part 2 (Weeks 16 to 52); no participants will receive placebo in Part 2. Part 3 is an observational period and each subject will continue to be monitored on a monthly basis through Week 72. Subjects will not receive any study medication during Part 3.

Inclusion Criteria:

• Adult participants (≥18 years of age) with a diagnosis of moderate-to-severe chronic plaque psoriasis (defined by ≥10% body surface area [BSA] involvement, "moderate" or greater score on the Physician's Global Assessment [PGA] scale, and PASI score ≥12 at Baseline)
• Participants must have a diagnosis of predominantly plaque psoriasis for ≥6 months (as determined by interview and confirmation of diagnosis through physical examination by investigator) and be considered candidates for phototherapy or systemic therapy. Participants with psoriatic arthritis may be included in the study

Exclusion Criteria:

• Nonplaque forms of psoriasis specifically erythrodermic psoriasis, predominantly pustular psoriasis, medication-induced or medication-exacerbated psoriasis, or new onset guttate psoriasis
• Participants who will require oral or injectable corticosteroids during the trial
• Presence of any infection requiring treatment with systemic antibiotics within 2 weeks prior to Screening, or serious infection (eg, pneumonia, cellulitis, bone or joint infections) requiring hospitalization or treatment with intravenous antibiotics within 8 weeks prior to Screening
• Participants with evidence of active or untreated latent tuberculosis (TB) according to Screening criteria specified in the protocol. (Prophylactic treatment for latent TB as per local guidelines must be initiated at least 4 weeks prior to treatment with study medication)
• Previous exposure to any agents targeting interleukin-12 (IL-12) and/or Interleukin-23 (IL-23)
• Participants with prior exposure to two or more tumor necrosis factor (TNF) antagonists with discontinuation due to lack of efficacy.