Drug Concentration, Immunogenicity, and Efficacy Study in Patients With Rheumatoid Arthritis Currently Treated With Etanercept, Adalimumab, or Infliximab

• Other: no intervention
  
  Other Name: Enbrel
• Other: no intervention
  
  Other Name: Humira
• Other: no intervention
  
  Other Name: Remicade

• etanercept
  
  Participants currently receiving etanercept treatment in a clinical setting for a minimum of 6 months and maximum of 24 months prior to study assessment visit.
  Intervention: Other: no intervention
• adalimumab
  
  Participants currently receiving adalimumab treatment in a clinical setting for a minimum of 6 months and maximum of 24 months prior to study assessment visit.
  Intervention: Other: no intervention
• infliximab
  
  Participants currently receiving infliximab treatment in a clinical setting for a minimum of 6 months and maximum of 24 months prior to study assessment visit.
  Intervention: Other: no intervention

Inclusion Criteria:

1. Age 18 years or older.
2. Diagnosis of RA based on the 1987 American College of Rheumatology revised criteria
3. Current continuous treatment with either etanercept, adalimumab, or infliximab for a minimum of 6 months and maximum of 24 months.

Exclusion Criteria:

1. Treatment with biosimilar or investigational etanercept, adalimumab, or infliximab within past 6 months.
2. Treatment with any other investigational drugs within past 3 months or five half lives of the drug, whichever is longer.
3. Any medical condition that would interfere with rheumatoid arthritis evaluation or other study assessments (eg, fibromyalgia, lupus).