A Study to Evaluate and Compare the Effectiveness and Metabolism of MK-0873 for the Treatment of Plaque Psoriasis (MK-0873-022-AM1)

Inclusion Criteria

• Is a male or female 18 to 65 years of age
• Female subjects of reproductive potential must have a negative serum pregnancy test at screening and agree to use and/or have their partner use two (2) acceptable methods of birth control
• Has a Body Mass Index (BMI) ≤36 kg/m^2 (up to 40 kg/m^2 may be enrolled, in consultation with Sponsor)
• Has diagnosis of plaque-type psoriasis at least 6 month prior to administration of study drug (participants with concurrent psoriatic arthritis may be enrolled)

• Has plaque-type psoriasis with at least two pairs of symmetrically located plaque lesions that exhibit similar baseline TLS values (TLS in each plaque ≥6 and

  ± 2 points difference between left and right plaque lesions)

• Has plaque-type psoriasis with lesion severity score ≥4 covering at least 1 to 20% of total body surface area (BSA) at screening and at baseline.
• Is judged to be in good health based on medical history, physical examination, vital sign measurements, electrocardiogram assessment, and laboratory safety tests

Exclusion Criteria

• Has nonplaque forms of psoriasis (e.g., Erythrodermic, guttate, or pustular).
• Has current drug-induced psoriasis (e.g., a new onset of psoriasis or an exacerbation of psoriasis from beta blockers, calcium channel blockers or lithium).
• Has received phototherapy or any systemic medications/treatments that could affect psoriasis or TLS evaluation (including but not limited to oral or injectable corticosteroids, retinoids, 1, 25-dihydroxy vitamin D3 and analogues, psoralens, sulfsalazine, hydroxyurea, fumaric acid derivatives, or herbal treatments) within 4 weeks of study drug administration.
• Has used topical medications/treatments that could affect psoriasis or TLS evaluation (e.g., corticosteroids, coal tar, anthralin, calcipotriene, topical vitamin D derivatives, retinoids, tazarotene, methoxsalen, trimethyl psoralens) within 2 weeks of study drug administration.
• Has used any systemic immunosuppressants (e.g., Methotrexate, azathioprine, cyclosporine, 6-thioguanine, mercaptopurine, mycophenolate mofetil, hydroxyurea, or tacrolimus) with 4 weeks of study drug administration or biologics (e.g., anti TNF, anti interleukins) with 3 months of study drug administration.