Inclusion Criteria:

   1. Males or female subjects 6 to 17 years of age, inclusive, at the time the informed
   consent form is signed by the legal guardian

   2. Subjects must have a weight of ≥ 20 kg

   3. Diagnosis of chronic plaque psoriasis for at least 6 months prior to Screening.

   4. Has moderate to severe plaque psoriasis at Screening and Baseline as defined by:

      - PASI score ≥ 12; and

      - Body surface area (BSA) ≥ 10%; and

      - sPGA ≥ 3 (moderate to severe)

   5. Disease inadequately controlled by or inappropriate for topical therapy for psoriasis

   6. Candidate for systemic therapy or phototherapy

Exclusion Criteria:

   1. Guttate, erythrodermic, or pustular psoriasis at Screening and Baseline

   2. Psoriasis flare or rebound within 4 weeks prior to Screening

   3. Prior history of suicide attempt at any time in the subject's lifetime prior to
   Screening or randomization in the study, or major psychiatric illness requiring
   hospitalization within 3 years prior to signing the assent and informed consent

   4. Answer "Yes" to any question on the Columbia-Suicide Severity Rating Scale during
   Screening or at Baseline

   5. Current or planned concurrent use of the following therapies that may have a possible
   effect on psoriasis

   a. Topical therapy within 2 weeks prior to randomization (including but not limited to
   topical corticosteroids, topical retinoid or vitamin D analog preparations,
   tacrolimus, pimecrolimus, or anthralin/dithranol)

   Exceptions*:

   i. Low potency or weak corticosteroids (please refer to the Investigators' Manual)
   will be allowed as background therapy for treatment of the face, axillae and groin in
   accordance with manufacturer's suggested usage ii. Unmedicated skin moisturizer (eg,
   Eucerin®) will also be permitted for body lesions

   *Subjects should not use these topical treatments within 24 hours prior to the clinic
   visit.

   b. Conventional systemic therapy for psoriasis within 4 weeks prior to randomization
   c. Phototherapy treatment (ie, ultraviolet B [UVB], PUVA) within 4 weeks prior to
   randomization d. Biologic therapy within 4 weeks prior to randomization or 5 PK/PD
   half-lives (whichever is longer).