The DAS28 is a continuous disease measure which is a composite of 4 variables: the 28 tender joint count, the 28 swollen joint count, ESR or C-reactive protein (CRP), and participant assessment of disease activity measure on a visual analogue scale. The DAS28 has numeric thresholds that define high disease activity (> 5.1), low disease activity (< 3.2) and remission (< 2.6). A clinically significant response is a decrease in DAS28 score of >1.2 from baseline.

The Intent-to-Treat (ITT) analysis population was defined to include all participants randomized into the study who received study medication. Participants were grouped according to the treatment or treatment regimen to which they were randomized. All participants who were randomized but never received study medication were excluded.

The DAS28 is a continuous disease measure which is a composite of 4 variables: the 28 tender joint count, the 28 swollen joint count, ESR or CRP, and participant assessment of disease activity measure on a visual analogue scale. The DAS28 has numeric thresholds that define high disease activity (> 5.1), low disease activity (< 3.2) and remission (< 2.6). A clinically significant response is a decrease in DAS28 score of >1.2 from baseline.

The Intent-to-Treat (ITT) analysis population was defined to include all participants randomized into the study who received study medication. Participants were grouped according to the treatment or treatment regimen to which they were randomized. All participants who were randomized but never received study medication were excluded.

The DAS28 is a continuous disease measure which is a composite of 4 variables: the 28 tender joint count, the 28 swollen joint count, ESR or CRP, and participant assessment of disease activity measure on a visual analogue scale. The DAS28 has numeric thresholds that define high disease activity (> 5.1), low disease activity (< 3.2) and remission (< 2.6). Clinically significant response= decrease in DAS28 score of >1.2 from baseline. DAS28 AUC can be calculated from the DAS28 score versus time curve, which provides an assessment of changes in disease activity over time.

The Intent-to-Treat (ITT) analysis population was defined to include all participants randomized into the study who received study medication. Participants were grouped according to the treatment or treatment regimen to which they were randomized. All participants who were randomized but never received study medication were excluded.

The disability section of the full HAQ includes 20 questions to assess physical functions in 8 domains: dressing, arising, eating, walking, hygiene, reach, grip and common activities. The questions are evaluated on a 4-point scale: 0=without any difficulty, 1= with some difficulty, 2= with much difficulty, and 3= unable to do. Higher scores= greater dysfunction. A disability index was calculated by summing the worst scores in each domain and dividing by the number of domains answered. Clinically meaningful HAQ response=an improvement of at least 0.3 units from baseline in HAQ disability Index.

The Intent-to-Treat (ITT) analysis population was defined to include all participants randomized into the study who received study medication. Participants were grouped according to the treatment or treatment regimen to which they were randomized. All participants who were randomized but never received study medication were excluded.

The disability section of the full HAQ includes 20 questions to assess physical functions in 8 domains: dressing, arising, eating, walking, hygiene, reach, grip and common activities. The questions are evaluated on a 4-point scale: 0=without any difficulty, 1= with some difficulty, 2= with much difficulty, and 3= unable to do. Higher scores= greater dysfunction. A disability index was calculated by summing the worst scores in each domain and dividing by the number of domains answered. Clinically meaningful HAQ response=an improvement of at least 0.3 units from baseline in HAQ disability Index.

The Intent-to-Treat (ITT) analysis population was defined to include all participants randomized into the study who received study medication. Participants were grouped according to the treatment or treatment regimen to which they were randomized. All participants who were randomized but never received study medication were excluded.

The disability section of the full HAQ includes 20 questions to assess physical functions in 8 domains: dressing, arising, eating, walking, hygiene, reach, grip and common activities. The questions are evaluated on a 4-point scale: 0=without any difficulty, 1= with some difficulty, 2= with much difficulty, and 3= unable to do. Higher scores= greater dysfunction. A disability index was calculated by summing the worst scores in each domain and dividing by the number of domains answered. Clinically meaningful HAQ response=an improvement of at least 0.3 units from baseline in HAQ disability Index.

The Intent-to-Treat (ITT) analysis population was defined to include all participants randomized into the study who received study medication. Participants were grouped according to the treatment or treatment regimen to which they were randomized. All participants who were randomized but never received study medication were excluded.

The disability section of the full HAQ includes 20 questions to assess physical functions in 8 domains: dressing, arising, eating, walking, hygiene, reach, grip and common activities. The questions are evaluated on a 4-point scale: 0=without any difficulty, 1= with some difficulty, 2= with much difficulty, and 3= unable to do. Higher scores= greater dysfunction. A disability index was calculated by summing the worst scores in each domain and dividing by the number of domains answered. Clinically meaningful HAQ response=an improvement of at least 0.3 units from baseline in HAQ disability Index.

Intent-to-Treat (ITT) Population: all participants randomized into the study receiving study medication, grouped according to randomization treatment. All participants randomized but never receiving study medication excluded. Although 3 participants in PLA group discontinued before Day 197, 2 of these patients were included in the LOCF analysis.

The SF-36 is a validated instrument measuring health-related quality of life across multiple disease states. It has 36 questions with 8 subscale scores and 2 summary scores (1) physical component summary=physical functioning, role-physical, bodily pain, and general health; (2) mental component summary=vitality, social functioning, role-emotional, and mental health. There is no total overall score; scoring is done for both subscores and summary scores. For subscores and summary scores, 0 =worst score (or quality of life) and 100=best score. Change from Baseline= post-Baseline - Baseline value.

ITT population, all participants randomized into the study receiving study medication. Participants grouped according to the treatment to which they were randomized. All randomized participants who never received study medication were excluded. SF-36 component scores were not presented in tabular form.

The SF-36 is a validated instrument measuring health-related quality of life across multiple disease states. It has 36 questions with 8 subscale scores and 2 summary scores (1) physical component summary=physical functioning, role-physical, bodily pain, and general health; (2) mental component summary=vitality, social functioning, role-emotional, and mental health. There is no total overall score; scoring is done for both subscores and summary scores. For subscores and summary scores, 0 =worst score (or quality of life) and 100=best score. Change from Baseline= post-Baseline - Baseline value.

ITT Population: all participants randomized into the study receiving study medication, grouped according to randomization treatment. Although 3 participants in PLA group discontinued before Day 197, 2 of these patients were included in the LOCF analysis. SF-36 component scores were not presented in tabular form.

The DAS28 is a continuous disease measure composite of 4 variables: 28 tender joint count, 28 swollen joint count, ESR or CRP, and participant assessment of disease activity measure on a visual analogue scale. High disease activity= > 5.1, low disease activity= < 3.2, and remission= < 2.6. Clinically significant response= decrease of >1.2 from baseline. Utilizing EULAR response criteria, DAS28 categorical responses define a good (absolute: <3.2 or >1.2 improvement from baseline [BL]), moderate (absolute: 3.2-5.1 or 0.6-1.2 change from BL), or no response (absolute: >5.1 or <0.6 change from BL)

The Intent-to-Treat (ITT) analysis population was defined to include all participants randomized into the study who received study medication. Participants were grouped according to the treatment or treatment regimen to which they were randomized. All participants who were randomized but never received study medication were excluded.

The ACR 20 definition of improvement is a 20% improvement from baseline in the number of tender and swollen joint counts, and a 20% improvement from baseline in 3 of the remaining 5 core set measures: participant global assessment of pain, participant global assessment of disease activity, physician global assessment of disease activity, participant assessment of physical function and acute phase reactant value (C-reactive protein [CRP]). The evaluation for 50% improvement (ACR 50) and 70% improvement (ACR 70) follow similarly.

The Intent-to-Treat (ITT) analysis population was defined to include all participants randomized into the study who received study medication. Participants were grouped according to the treatment or treatment regimen to which they were randomized. All participants who were randomized but never received study medication were excluded.

The ACR 20 definition of improvement is a 20% improvement from baseline in the number of tender and swollen joint counts, and a 20% improvement from baseline in 3 of the remaining 5 core set measures: participant global assessment of pain, participant global assessment of disease activity, physician global assessment of disease activity, participant assessment of physical function and acute phase reactant value (C-reactive protein [CRP]). The evaluation for 50% improvement (ACR 50) and 70% improvement (ACR 70) follow similarly.

The Intent-to-Treat (ITT) analysis population was defined to include all participants randomized into the study who received study medication. Participants were grouped according to the treatment or treatment regimen to which they were randomized. All participants who were randomized but never received study medication were excluded.

AE=any new untoward medical occurrence or worsening of a pre-existing medical condition which does not necessarily have a causal relationship with this treatment. SAE=any untoward medical occurrence that at any dose: results in death, is life-threatening, requires inpatient hospitalization or causes prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, results in development of drug dependency or drug abuse, is an important medical event.

The As-Treated analysis population contained all participants who received at least one dose of double-blind study medication, and participants were grouped on an as-assigned or randomized basis unless the participant received the incorrect medication for the entire period of treatment.

AE=any new untoward medical occurrence or worsening of a pre-existing medical condition which does not necessarily have a causal relationship with this treatment. AEs of special interest are those AEs that may be associated with the use of immunomodulatory drugs, including all infections, serious infections, autoimmune disorders; malignancies; and acute infusional AEs (pre-specified AEs occurring within 1 hour of start of infusion).

The As-Treated analysis population contained all participants who received at least one dose of double-blind study medication, and participants were grouped on an as-assigned or randomized basis unless the participant received the incorrect medication for the entire period of treatment.

AE=any new untoward medical occurrence or worsening of a pre-existing medical condition which does not necessarily have a causal relationship with this treatment. SAE=any untoward medical occurrence that at any dose: results in death, is life-threatening, requires inpatient hospitalization or causes prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, results in development of drug dependency or drug abuse, is an important medical event.

The As-Treated analysis population contained all participants who received at least one dose of double-blind study medication, and participants were grouped on an as-assigned or randomized basis unless the participant received the incorrect medication for the entire period of treatment.

AE=any new untoward medical occurrence or worsening of a pre-existing medical condition which does not necessarily have a causal relationship with this treatment. SAE=any untoward medical occurrence that at any dose: results in death, is life-threatening, requires inpatient hospitalization or causes prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, results in development of drug dependency or drug abuse, is an important medical event.

The As-Treated analysis population contained all participants who received at least one dose of double-blind study medication, and participants were grouped on an as-assigned or randomized basis unless the participant received the incorrect medication for the entire period of treatment.

AE=any new untoward medical occurrence or worsening of a pre-existing medical condition which does not necessarily have a causal relationship with this treatment. SAE=any untoward medical occurrence that at any dose: results in death, is life-threatening, requires inpatient hospitalization or causes prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, results in development of drug dependency or drug abuse, is an important medical event.

All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period.

AE=any new untoward medical occurrence or worsening of a pre-existing medical condition which does not necessarily have a causal relationship with this treatment. AEs of special interest are those AEs that may be associated with the use of immunomodulatory drugs, including all infections, serious infections, autoimmune disorders; malignancies; and acute infusional AEs (pre-specified AEs occurring within 1 hour of start of infusion).

All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period.

High=greater than Upper Normal Limit (ULN), Low=lower than Lower Normal Limit (LLN). LLN/ULN= Hemoglobin (HGB): >3 g/dL decrease from Baseline (BL); Hematocrit: <0.75 x BL; Erythrocytes: <0.75 x BL; Platelets (PLT): <0.67 x LLN/>1.5 x ULN; Leukocytes: <0.75 x LLN/ >1.25 x ULN; neutrophils+bands: <1.0 x 10^3 c/uL; lymphocytes: <0.750 x 10^3 c/uL/ >7.50 x 10^3 c/uL; monocytes: >2000 mm3; eosinophils: >0.750 x 10^3 c/uL;

All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period.

Low=lower than LLN, High=greater than ULN. LLN/ULN= Alkaline phosphatase (ALP): >2 x ULN; aspartate aminotransferase (AST): >3 x ULN; alanine aminotransferase (ALT): >3 x ULN; G-Glutamyl transferase (GGT): >2 x ULN; Bilirubin: >2 x ULN; blood urea nitrogen (BUN): >2 x BL; creatinine: >4 x BL

All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period.

AE=any new untoward medical occurrence or worsening of a pre-existing medical condition which does not necessarily have a causal relationship with this treatment. AEs of special interest are those AEs that may be associated with the use of immunomodulatory drugs, including all infections, serious infections, autoimmune disorders; malignancies; and acute infusional AEs (pre-specified AEs occurring within 1 hour of start of infusion).

The As-Treated analysis population contained all participants who received at least one dose of double-blind study medication, and participants were grouped on an as-assigned or randomized basis unless the participant received the incorrect medication for the entire period of treatment.

AE=any new untoward medical occurrence or worsening of a pre-existing medical condition which does not necessarily have a causal relationship with this treatment. AEs of special interest are those AEs that may be associated with the use of immunomodulatory drugs, including all infections, serious infections, autoimmune disorders; malignancies; and acute infusional AEs (pre-specified AEs occurring within 1 hour of start of infusion).

The As-Treated analysis population contained all participants who received at least one dose of double-blind study medication, and participants were grouped on an as-assigned or randomized basis unless the participant received the incorrect medication for the entire period of treatment.

Seated Systolic Blood Pressure (SBP) and Diastolic Blood Pressure (DBP) were assessed as clinically significant or relevant at the discretion of the Clinical Investigator. Criteria may have varied between institutions.

As-Treated Population

Heart Rate (HR) was assessed as clinically significant or relevant at the discretion of the Clinical Investigator. Criteria may have varied between institutions.

As Treated Population.

Temperature (T) was assessed as clinically significant or relevant at the discretion of the Clinical Investigator. Criteria may have varied between institutions.

As Treated Population.

High=greater than Upper Normal Limit (ULN), Low=lower than Lower Normal Limit (LLN). LLN/ULN= Hemoglobin (HGB): >3 g/dL decrease from Baseline (BL); Hematocrit: <0.75 x BL; Platelets (PLT): <0.67 x LLN/>1.5 x ULN; Leukocytes: <0.75 x LLN/ >1.25 x ULN; neutrophils+bands: <1.0 x 10^3 c/uL; aspartate aminotransferase (AST): >3 x ULN; alanine aminotransferase (ALT): >3 x ULN; creatinine: >4 x BL

The As-Treated analysis population contained all participants who received at least one dose of double-blind study medication, and participants were grouped on an as-assigned or randomized basis unless the participant received the incorrect medication for the entire period of treatment.

High=greater than Upper Normal Limit (ULN), Low=lower than Lower Normal Limit (LLN). LLN/ULN= Hemoglobin (HGB): >3 g/dL decrease from Baseline (BL); Hematocrit: <0.75 x BL; Platelets (PLT): <0.67 x LLN/>1.5 x ULN; Leukocytes: <0.75 x LLN/ >1.25 x ULN; neutrophils+bands: <1.0 x 10^3 c/uL; aspartate aminotransferase (AST): >3 x ULN; alanine aminotransferase (ALT): >3 x ULN; creatinine: >4 x BL

The As-Treated analysis population contained all participants who received at least one dose of double-blind study medication, and participants were grouped on an as-assigned or randomized basis unless the participant received the incorrect medication for the entire period of treatment.

ECL screened sera for drug-specific antibodies, immunocompetition was used to identify specific anti-Abatacept reactivity. Cytotoxic leukocyte antigen 4 (CTLA4) and Possibly Immunoglobulin (Ig) Category=reactivity against extracellular domain of human CTLA4, constant regions of human IgG1, or both (CTLA4Ig; Abatacept molecule). Ig and/or Junction Category=reactivity against constant regions and/or hinge region of human IgG1. Drug-induced seropositivity was defined as a post-baseline titer higher than Baseline, or any post-baseline positivity if Baseline value was missing.

The immunogenicity analysis population included participants who received at least one dose of abatacept and had immunogenicity samples collected at baseline and at least one post-baseline treatment visit.

Infliximab levels were measured using a microplate enzyme-linked immunosorbant assay (ELISA) with infliximab bound to immobilized recombinant tumor necrosis factor (TNF)-alpha. Bound infliximab is detected utilizing a horseradish peroxidase-conjugated anti-human IgG Fc(fragment, crystallizable region)-specific). The enzyme turns over the substrate O-phenlenediamine to a chromogenic product that is measured at 490 nm. The cut-off value was 1.40 ug/mL; this was based on the mean (+ 3 SD) value in serum samples from 40 participants who had never received infliximab.

The immunogenicity analysis population included participants who received at least one dose of infliximab and had immunogenicity samples collected at baseline and at least one post-baseline treatment visit.

Hemoglobin (HGB): >3 g/dL decrease from BL; total protein: < 0.9 x LLN, >1.1 x ULN; albumin:<0.9 x LLN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Platelets (PLT): <0.67 x LLN, >1.5 x ULN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Hematocrit: <0.75 x BL

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Leukocytes: <0.75 x LLN, >1.25 x ULN; neutrophils+bands: <1.0 x 10^3 c/uL; eosinophils: >0.750 x 10^3 c/uL; basophils: > 400 mm3; monocytes: >2000 mm3; lymphocytes: <0.750 x 10^3 c/uL, >7.50 x 10^3 c/uL.

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Erythrocytes: <0.75 x BL

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Sodium (Na): <0.95 x LLN, >1.05 x ULN; potassium (K): <0.9 x LLN, >1.1 x ULN; chloride (Cl): <0.9 x LLN, >1.1 x ULN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Bilirubin: >2 x ULN; blood urea nitrogen (BUN): >2 x BL; creatinine: >4 x BL; calcium (Ca): <0.8 x LLN, >1.2 x ULN; phosphorous (P): <0.75 x LLN, >1.2 5 x ULN; serum glucose (Glu): <65 mg/dL, >220 mg/dL; fasting serum Glu: <0.8 x LLN, >1.5 x ULN; uric acid: >1.5 x ULN;

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

alanine aminotransferase (ALT): >3 x ULN; aspartate aminotransferase (AST): >3 x ULN; G-Glutamyl transferase (GGT): >2 x ULN; Alkaline phosphatase (ALP): >2 x ULN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Hemoglobin (HGB): >3 g/dL decrease from BL; total protein: < 0.9 x LLN, >1.1 x ULN; albumin:<0.9 x LLN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Platelets (PLT): <0.67 x LLN, >1.5 x ULN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Hematocrit: <0.75 x BL

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

The DAS28 is a continuous disease measure which is a composite of 4 variables: the 28 tender joint count, the 28 swollen joint count, ESR or CRP, and participant assessment of disease activity measure on a visual analogue scale. The DAS28 has numeric thresholds that define high disease activity (> 5.1), low disease activity (< 3.2) and remission (< 2.6). A clinically significant response is a decrease in DAS28 score of >1.2 from baseline.

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period.n=number of participants with data available.

The DAS28 is a continuous disease measure which is a composite of 4 variables: the 28 tender joint count, the 28 swollen joint count, ESR or CRP, and participant assessment of disease activity measure on a visual analogue scale. The DAS28 has numeric thresholds that define high disease activity (> 5.1), low disease activity (< 3.2) and remission (< 2.6). A clinically significant response is a decrease in DAS28 score of >1.2 from baseline.

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Efficacy data was summarized for the 3 DB treatment cohorts.n=number of participants with data available.

The DAS28 is a continuous disease measure composite of 4 variables: 28 tender joint count, 28 swollen joint count, ESR or CRP, and participant assessment of disease activity measure on a visual analogue scale. High disease activity= > 5.1, low disease activity= < 3.2, and remission= < 2.6. Clinically significant response= decrease of >1.2 from baseline. Utilizing EULAR response criteria, DAS28 categorical responses define a good (absolute <3.2 or >1.2 improvement from baseline [BL]), moderate (absolute 3.2-5.1 or 0.6-1.2 change from BL), or no response (absolute >5.1 or <0.6 change from BL)

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period.n=number of participants with data available.

The ACR 20 definition of improvement is a 20% improvement from baseline in the number of tender and swollen joint counts, and a 20% improvement from baseline in 3 of the remaining 5 core set measures: participant global assessment of pain, participant global assessment of disease activity, physician global assessment of disease activity, participant assessment of physical function and acute phase reactant value (C-reactive protein [CRP]). The evaluation for 50% improvement (ACR 50) and 70% improvement (ACR 70) follow similarly.

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Major Clinical Response was defined as a continuous ACR 70 for six months.

Protocol-specified analyses of the proportion of participants achieving a Major Clinical Response were not performed since ACR responses in the open-label period could only be assessed at 6-month intervals due to the fact that CRP and ESR were only measured every 6 months during this period.

The disability section of the full HAQ includes 20 questions to assess physical functions in 8 domains: dressing, arising, eating, walking, hygiene, reach, grip and common activities. The questions are evaluated on a 4-point scale: 0=without any difficulty, 1= with some difficulty, 2= with much difficulty, and 3= unable to do. Higher scores= greater dysfunction. A disability index was calculated by summing the worst scores in each domain and dividing by the number of domains answered. Clinically meaningful HAQ response=an improvement of at least 0.3 units from baseline in HAQ disability Index.

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period.n=number of participants with data available.

The disability section of the full HAQ includes 20 questions to assess physical functions in 8 domains: dressing, arising, eating, walking, hygiene, reach, grip and common activities. The questions are evaluated on a 4-point scale: 0=without any difficulty, 1= with some difficulty, 2= with much difficulty, and 3= unable to do. Higher scores= greater dysfunction. A disability index was calculated by summing the worst scores in each domain and dividing by the number of domains answered. Clinically meaningful HAQ response=an improvement of at least 0.3 units from baseline in HAQ disability Index.

All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period.

Leukocytes: <0.75 x LLN, >1.25 x ULN; neutrophils+bands: <1.0 x 10^3 c/uL; eosinophils: >0.750 x 10^3 c/uL; basophils: > 400 mm3; monocytes: >2000 mm3; lymphocytes: <0.750 x 10^3 c/uL, >7.50 x 10^3 c/uL.

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Erythrocytes: <0.75 x BL

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Sodium (Na): <0.95 x LLN, >1.05 x ULN; potassium (K): <0.9 x LLN, >1.1 x ULN; chloride (Cl): <0.9 x LLN, >1.1 x ULN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Bilirubin: >2 x ULN; blood urea nitrogen (BUN): >2 x BL; creatinine: >4 x BL; calcium (Ca): <0.8 x LLN, >1.2 x ULN; phosphorous (P): <0.75 x LLN, >1.2 5 x ULN; serum glucose (Glu): <65 mg/dL, >220 mg/dL; fasting serum Glu: <0.8 x LLN, >1.5 x ULN; uric acid: >1.5 x ULN;

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

alanine aminotransferase (ALT): >3 x ULN; aspartate aminotransferase (AST): >3 x ULN; G-Glutamyl transferase (GGT): >2 x ULN; Alkaline phosphatase (ALP): >2 x ULN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Hemoglobin (HGB): >3 g/dL decrease from BL; total protein: < 0.9 x LLN, >1.1 x ULN; albumin:<0.9 x LLN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Platelets (PLT): <0.67 x LLN, >1.5 x ULN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Hematocrit: <0.75 x BL

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Leukocytes: <0.75 x LLN, >1.25 x ULN; neutrophils+bands: <1.0 x 10^3 c/uL; eosinophils: >0.750 x 10^3 c/uL; basophils: > 400 mm3; monocytes: >2000 mm3; lymphocytes: <0.750 x 10^3 c/uL, >7.50 x 10^3 c/uL.

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Erythrocytes: <0.75 x BL

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Sodium (Na): <0.95 x LLN, >1.05 x ULN; potassium (K): <0.9 x LLN, >1.1 x ULN; chloride (Cl): <0.9 x LLN, >1.1 x ULN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Bilirubin: >2 x ULN; blood urea nitrogen (BUN): >2 x BL; creatinine: >4 x BL; calcium (Ca): <0.8 x LLN, >1.2 x ULN; phosphorous (P): <0.75 x LLN, >1.2 5 x ULN; serum glucose (Glu): <65 mg/dL, >220 mg/dL; fasting serum Glu: <0.8 x LLN, >1.5 x ULN; uric acid: >1.5 x ULN;

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

alanine aminotransferase (ALT): >3 x ULN; aspartate aminotransferase (AST): >3 x ULN; G-Glutamyl transferase (GGT): >2 x ULN; Alkaline phosphatase (ALP): >2 x ULN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Hemoglobin (HGB): >3 g/dL decrease from BL; total protein: < 0.9 x LLN, >1.1 x ULN; albumin:<0.9 x LLN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Platelets (PLT): <0.67 x LLN, >1.5 x ULN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Hematocrit: <0.75 x BL

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Leukocytes: <0.75 x LLN, >1.25 x ULN; neutrophils+bands: <1.0 x 10^3 c/uL; eosinophils: >0.750 x 10^3 c/uL; basophils: > 400 mm3; monocytes: >2000 mm3; lymphocytes: <0.750 x 10^3 c/uL, >7.50 x 10^3 c/uL.

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Erythrocytes: <0.75 x BL

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Sodium (Na): <0.95 x LLN, >1.05 x ULN; potassium (K): <0.9 x LLN, >1.1 x ULN; chloride (Cl): <0.9 x LLN, >1.1 x ULN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Bilirubin: >2 x ULN; blood urea nitrogen (BUN): >2 x BL; creatinine: >4 x BL; calcium (Ca): <0.8 x LLN, >1.2 x ULN; phosphorous (P): <0.75 x LLN, >1.2 5 x ULN; serum glucose (Glu): <65 mg/dL, >220 mg/dL; fasting serum Glu: <0.8 x LLN, >1.5 x ULN; uric acid: >1.5 x ULN;

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

alanine aminotransferase (ALT): >3 x ULN; aspartate aminotransferase (AST): >3 x ULN; G-Glutamyl transferase (GGT): >2 x ULN; Alkaline phosphatase (ALP): >2 x ULN

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period. Treatment groups represent treatment received in the DB period. n=number of participants with data available.

Seated Systolic Blood Pressure (SBP) and Diastolic Blood Pressure (DBP), units=mm mercury (Hg)

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period.n=number of participants with data available.

Heart Rate (HR), units=beats per minute (bpm)

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period.n=number of participants with data available.

Temperature (T), units=degrees Celcius

Number of Participants Analyzed=All Treated Population, all participants who entered the open-label period and received at least one dose of abatacept at any time during this period.n=number of participants with data available.