A Study of the Efficacy and Safety of Adalimumab in Pediatric Subjects With Enthesitis Related Arthritis.

• Percent change in the number of active joints with arthritis [ Time Frame: Week 12 ] [ Designated as safety issue: Yes ]
  Assessment of joints with swelling not due to deformity or joints with loss of motion plus pain and/or tenderness
• Adverse Events [ Time Frame: At every visit from Baseline (Week 0) to final Visit (Week 156) ] [ Designated as safety issue: Yes ]
  Any untoward medical occurrence

• Percent change in the number of active joints with arthritis [ Time Frame: Week 12 ] [ Designated as safety issue: No ]
  Assessment of tender and swollen joints and joints with limitation of motion
• Adverse Events [ Time Frame: At every visit from Baseline (Week 0) to final Visit (Week 156) ] [ Designated as safety issue: Yes ]
  Any untoward medical occurrence

• Entheses [ Time Frame: Week 12 ] [ Designated as safety issue: No ]
  The presence or absence of enthesitis at 35 different anatomical locations
• Tender Joint Count [ Time Frame: Week 12 ] [ Designated as safety issue: No ]
  The presence or absence of joint tenderness at 72 joints
• Swollen Joint Count [ Time Frame: Week 12 ] [ Designated as safety issue: No ]
  The presence or absence of joint swelling at 68 joints.
• American College of Rheumatology (ACR) Pediatric 30, 50 and 70 [ Time Frame: Week 12 ] [ Designated as safety issue: No ]
  30, 50 and 70% improvement, respectively, in at least three of the six Juvenile Rheumatoid Arthritis (JRA) core set criteria, with 30% worsening in no more than one of the six JRA core set criteria.

• Entheses [ Time Frame: Week 12 ] [ Designated as safety issue: No ]
  The presence or absence of enthesitis at 27 different anatomical locations
• Tender Joint Count [ Time Frame: Week 12 ] [ Designated as safety issue: No ]
  The presence or absence of joint tenderness at 72 joints
• Swollen Joint Count [ Time Frame: Week 12 ] [ Designated as safety issue: No ]
  The presence or absence of joint swelling at 68 joints.
• ACR 30, 50 and 70 [ Time Frame: Week 12 ] [ Designated as safety issue: No ]
  30, 50 and 70% improvement respectively, with no more than 30% worsening in a core set of variables.

The study will evaluate how well adalimumab works and how safe it is in the treatment of children with Enthesitis Related Arthritis.

• Biological: adalimumab - blinded
  blinded adalimumab BSA dosing 24mg/m^2, max 40 mg
  Other Names:

  • ABT-D2E7
  • Humira
• Biological: placebo for adalimumab - blinded
  blinded matching placebo for adalimumab, matching BSA dosing
• Drug: Adalimumab - open label
  open-label adalimumab BSA dosing 24mg/m^2, max 40 mg
  Other Names:

  • ABT-D2E7
  • Humira

• Experimental: Adalimumab - Blinded
  Intervention: Biological: adalimumab - blinded
• Placebo Comparator: Placebo - Blinded
  Intervention: Biological: placebo for adalimumab - blinded
• Experimental: Adalimumab - Open Label
  Intervention: Drug: Adalimumab - open label

Inclusion Criteria:

• Age 6 through 17 years;
• Diagnosis of Enthesitis Related Arthritis (ERA) as defined by International League of Associations for Rheumatology (ILAR);
• Disease activity defined as at least 3 active joints and evidence of enthesitis in at least one location;
• Inadequate response or intolerance to at least one nonsteroidal anti-inflammatory drug and at least one disease modifying anti-rheumatic drug, either sulfasalazine or methotrexate.

Exclusion Criteria:

• Any ILAR Juvenile Idiopathic Arthritis (JIA) subtype other than ERA;
• Psoriasis or a history of psoriasis in the patient or first-degree relative;
• Presence of Immunoglobulin M (IgM) rheumatoid factor; Presence of systemic JIA,
• History of inflammatory bowel disease, previous biologic therapy including anti-TNF therapy with a potential impact on pediatric ERA;
• Infection(s) requiring treatment with IV anti-infectives within 30 days prior to Baseline or oral anti-infectives within 14 days prior to Baseline