A Double Blind Study in Pediatric Subjects With Chronic Plaque Psoriasis, Studying Adalimumab vs. Methotrexate

Inclusion Criteria:

1. Subject is ≥ 4 years and < 18 years of age;

2. Subject weighs ≥ 13 kg;

3. Subject must have failed to respond to topical therapy;

4. Subject must need systemic treatment to control his/her disease and meet one of thefollowing:

• Physician's Global Assessment (PGA) ≥ 4

• Body surface area (BSA) involved > 20%

• Very thick lesions with BSA > 10%

• Psoriasis Area and Severity Index (PASI) > 20

• PASI > 10 and at least one of the following:

• Active psoriatic arthritis unresponsive to non-steroid anti-inflammatorydrugs (NSAIDs)

• Clinically relevant facial involvement

• Clinically relevant genital involvement

• Clinically relevant hand and/or foot involvement

• Children's Dermatology Life Quality Index (CDLQI) > 10

5. If subject is < 12 years of age and resides in a geographic region where heliotherapyis practical, subject must have failed to respond, be intolerant, or have acontraindication to heliotherapy, or is not a suitable candidate for heliotherapy;

6. If ≥ 12 years of age, subject must have failed to respond, be intolerant, or have acontraindication to phototherapy, or is not a suitable candidate for phototherapy;

7. Subject must have a clinical diagnosis of psoriasis for at least 6 months asdetermined by the subject's medical history and confirmation of diagnosis throughphysical examination by the Investigator;

8. Subject must have stable plaque psoriasis for at least 2 months prior to Baseline

Exclusion Criteria:

1. Prior biologic use other than prior treatment with etanercept;

2. Treatment with etanercept therapy within 4 weeks prior to the Baseline visit; 3.Methotrexate (MTX) use within the past year or prior MTX use at any time where thesubject did not respond, or did not tolerate MTX;

3. Contraindication for treatment with MTX during the study; 5. Erythrodermic psoriasis,generalized or localized pustular psoriasis, medication-induced or medication exacerbatedpsoriasis or new onset guttate psoriasis; 6. Infection(s) requiring treatment withintravenous (IV) anti-infectives within 30 days prior to the Baseline Visit or oralanti-infectives within 14 days prior to the Baseline Visit; 7. Treatment of psoriasis withtopical therapies such as corticosteroids, vitamin D analogs, or retinoids within 7 daysprior to the Baseline visit; 8. Treatment of psoriasis with ultraviolet (UV)B phototherapy,excessive sun exposure, or the use of tanning beds within 7 days prior to the Baselinevisit; 9. Treatment of psoriasis with ultraviolet A with psoralen (PUVA) phototherapy,non-biologic systemic therapies for the treatment of psoriasis, or systemic therapies knownto improve psoriasis within 14 days prior to the Baseline visit.