A Study in Rheumatoid Arthritis (RA) Patients to Compare Two Formulations of Adalimumab for Pharmacokinetic, Pharmacodynamic and Safety

American College of Rheumatology 20% (ACR20) response. A participant is a responder if the following 3 criteria for improvement from baseline are met:

• ≥ 20% improvement in tender joint count;
• ≥ 20% improvement in swollen joint count; and
• ≥ 20% improvement in at least 3 of the 5 following parameters:
• Physician global assessment of disease activity
• Patient global assessment of disease activity
• Patient assessment of pain
• Disability Index of the Health Assessment Questionnaire
• CRP (Acute phase reactant (Erythrocyte sedimentation rate/C-reactive protein))

American College of Rheumatology 50% (ACR50) response. A participant is a responder if the following 3 criteria for improvement from baseline are met:

• ≥ 50% improvement in tender joint count;
• ≥ 50% improvement in swollen joint count; and
• ≥ 50% improvement in at least 3 of the 5 following parameters:
• Physician global assessment of disease activity
• Patient global assessment of disease activity
• Patient assessment of pain
• Disability Index of the Health Assessment Questionnaire
• CRP (Acute phase reactant (Erythrocyte sedimentation rate/C-reactive protein))

The Health Assessment Questionnaire - Disability Index (HAQ-DI) is a patient-reported questionnaire specific for rheumatoid arthritis. It consists of 20 questions referring to eight domains: dressing/grooming, arising, eating, walking, hygiene, reach, grip, and daily activities. Participants assessed their ability to do each task over the past week using the following response categories: without any difficulty (0); with some difficulty (1); with much difficulty (2); and unable to do (3). Scores on each task were summed and averaged to provide an overall score ranging from 0 to 3, where zero represents no disability and three very severe, high-dependency disability. The minimal clinically important difference (MCID) defined for the HAQ-DI is ≥0.22. HAQ remission indicating normal physical function is defined by HAQ-DI < 0.5.

The Short Form 36 (SF-36) determines participants' overall quality of life by assessing 1) limitations in physical functioning due to health problems; 2) limitations in usual role because of physical health problems; 3) bodily pain; 4) general health perceptions; 5) vitality; 6) limitations in social functioning because of physical or emotional problems; 7) limitations in usual role due to emotional problems; and 8) general mental health. Items 1-4 primarily contribute to the physical component summary score (PCS) of the SF-36. Items 5-8 primarily contribute to the mental component summary score (MCS) of the SF-36. Scores on each item are summed and averaged (range = 0 (maximum disability) - 100 (no disability). The standard recall period is four weeks.

Percentage of participants with anti-adalimumab antibody

An adverse event was defined as any untoward medical occurrence in a patient or clinical investigation subject administered a pharmaceutical product and which did not necessarily have a causal relationship with the treatment. See the Reported Adverse Events Section for more details.

The Visual Analogue Scale (VAS) consisted of a horizontal 100 mm line, with 0 representing "no pain" and 100 representing "worst possible pain". Participants placed a mark on the line representing their current level of pain immediately after injections on Day 1 of the study.