Trial Outcomes & Findings for Abatacept in the Treatment and Prevention of Active Systemic Lupus Erythematosus (SLE) Flares in Combination With Prednisone (NCT NCT00119678)

NCT ID: NCT00119678

Last Updated: 2014-09-22

Results Overview

SLE flares scored using BILAG:A:presence of =\>1 serious;B:more moderate;C:mild symptomatic;D:prior activity,no current symptoms;E:organ that has never been involved. Calculated based on change during previous 4 weeks (1=improving,2=staying same,3=worsening,4=new).New SLE flare:first BILAG 'A' or 'B' event adjudicated to be flare following resolution of entry flare and start of prednisone/prednisone-equivalent taper.Inception treatment failure included (entry flare did not subside by Day 57/participant discontinued double-blind period before Day 29).

• Recruitment status: COMPLETED
• Study phase: PHASE2
• Target enrollment: 183 participants
• Primary outcome timeframe: From start of corticosteroid taper to Day 365
• Results posted on: 2014-09-22

Participant Flow

263 participants were enrolled in this study and 80 were excluded from the trial due to screening failure. Of the 183 randomized, 3 were not treated and 5 were treated but excluded due to site closure.

Participant milestones

Measure	Abatacept Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
Double-blind Treatment Period STARTED	122	61
Double-blind Treatment Period RANDOMIZED AND TREATED	121	59
Double-blind Treatment Period RANDOMIZED,TREATED, AND ANALYZED	118	57
Double-blind Treatment Period COMPLETED	81	35
Double-blind Treatment Period NOT COMPLETED	41	26
Open-label Treatment Period STARTED	110	0
Open-label Treatment Period COMPLETED	0	0
Open-label Treatment Period NOT COMPLETED	110	0

Reasons for withdrawal

Measure	Abatacept Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
Double-blind Treatment Period Death	1	0
Double-blind Treatment Period Adverse Event	7	1
Double-blind Treatment Period Lack of Efficacy	21	12
Double-blind Treatment Period Lost to Follow-up	1	2
Double-blind Treatment Period Participant withdrew consent	4	4
Double-blind Treatment Period Participants not meeting study criteria	0	1
Double-blind Treatment Period Poor/Non-compliance	3	0
Double-blind Treatment Period Pregnancy	0	2
Double-blind Treatment Period Not treated	1	2
Double-blind Treatment Period Site closed due to non-compliance	3	2
Open-label Treatment Period Death	1	0
Open-label Treatment Period Adverse Event	3	0
Open-label Treatment Period Lack of Efficacy	9	0
Open-label Treatment Period Lost to Follow-up	3	0
Open-label Treatment Period Participant withdrew consent	4	0
Open-label Treatment Period Participants not meeting study criteria	2	0
Open-label Treatment Period Pregnancy	1	0
Open-label Treatment Period Administrative reasons by sponsor	87	0

Baseline Characteristics

Abatacept in the Treatment and Prevention of Active Systemic Lupus Erythematosus (SLE) Flares in Combination With Prednisone

Baseline characteristics by cohort

Measure	Abatacept n=118 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=57 Participants Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Total n=175 Participants Total of all reporting groups
Age, Continuous	38.0 years FULL_RANGE 12.76 • n=5 Participants	36.0 years n=7 Participants	38.0 years n=5 Participants
Sex: Female, Male Female	104 Participants n=5 Participants	55 Participants n=7 Participants	159 Participants n=5 Participants
Sex: Female, Male Male	14 Participants n=5 Participants	2 Participants n=7 Participants	16 Participants n=5 Participants
Race/Ethnicity, Customized White	74 participants n=5 Participants	39 participants n=7 Participants	113 participants n=5 Participants
Race/Ethnicity, Customized Black/African American	12 participants n=5 Participants	4 participants n=7 Participants	16 participants n=5 Participants
Race/Ethnicity, Customized American Indian/Alaska Native	1 participants n=5 Participants	0 participants n=7 Participants	1 participants n=5 Participants
Race/Ethnicity, Customized Asian	28 participants n=5 Participants	13 participants n=7 Participants	41 participants n=5 Participants
Race/Ethnicity, Customized Other races	3 participants n=5 Participants	1 participants n=7 Participants	4 participants n=5 Participants
Weight	68.630 kilograms STANDARD_DEVIATION 18.717 • n=5 Participants	69.000 kilograms STANDARD_DEVIATION 14.790 • n=7 Participants	68.750 kilograms STANDARD_DEVIATION 17.493 • n=5 Participants
Systemic Lupus International Collaborative Clinics/American College of Rheumatology(SLICC/ACC) score Overall SLICC/ACR score 0	82 participants n=5 Participants	38 participants n=7 Participants	120 participants n=5 Participants
Systemic Lupus International Collaborative Clinics/American College of Rheumatology(SLICC/ACC) score Overall SLICC/ACR score 1	12 participants n=5 Participants	11 participants n=7 Participants	23 participants n=5 Participants
Systemic Lupus International Collaborative Clinics/American College of Rheumatology(SLICC/ACC) score Overall SLICC/ACR score 2	15 participants n=5 Participants	5 participants n=7 Participants	20 participants n=5 Participants
Systemic Lupus International Collaborative Clinics/American College of Rheumatology(SLICC/ACC) score Overall SLICC/ACR score >2	6 participants n=5 Participants	1 participants n=7 Participants	7 participants n=5 Participants
Systemic Lupus International Collaborative Clinics/American College of Rheumatology(SLICC/ACC) score Overall SLICC/ACR score unavailable	3 participants n=5 Participants	2 participants n=7 Participants	5 participants n=5 Participants

PRIMARY outcome

Timeframe: From start of corticosteroid taper to Day 365

Population: All randomized and treated participants, grouped by the treatment randomized to (Intent to Treat \[ITT\]). Participants who were inception treatment failures were treated as having 1 new flare; participants who discontinued early without any new flares were treated as having 1 new flare.

SLE flares scored using BILAG:A:presence of =>1 serious;B:more moderate;C:mild symptomatic;D:prior activity,no current symptoms;E:organ that has never been involved. Calculated based on change during previous 4 weeks (1=improving,2=staying same,3=worsening,4=new).New SLE flare:first BILAG 'A' or 'B' event adjudicated to be flare following resolution of entry flare and start of prednisone/prednisone-equivalent taper.Inception treatment failure included (entry flare did not subside by Day 57/participant discontinued double-blind period before Day 29).

Outcome measures

Measure	Abatacept n=118 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=57 Participants Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
Double Blind Period (DB); Number of Participants Experiencing a New SLE Flare	94 Participants Interval 72.4 to 86.9	47 Participants Interval 72.6 to 92.3

PRIMARY outcome

Timeframe: From start of study drug therapy in open-label period (Day 365) up to 56 days after the last dose of open-label period

Population: As treated analysis population: All treated participants who entered the open-label period and received at least one dose of study medication during open-label period.

AEs: any new untoward medical occurrences/worsening of pre-existing medical condition, whether or not related to study drug. SAE: any AE that resulted in death; was life threatening; resulted in persistent/significant disability/incapacity; resulted in/prolonged an existing in-patient hospitalization; was a congenital anomaly/birth defect; or was an overdose. Participants who discontinued the study due to an AE were recorded. Drug-related AEs or SAEs: events with a relationship to the study therapy of certain; probable; possible; or missing.

Outcome measures

Measure	Abatacept n=110 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
Open Label Period (OL); Number of Participants Who Died, Experienced Adverse Events (AEs), Serious AEs, Drug Related AEs or SAEs and Discontinued Due to AEs Deaths	1 participants	—
Open Label Period (OL); Number of Participants Who Died, Experienced Adverse Events (AEs), Serious AEs, Drug Related AEs or SAEs and Discontinued Due to AEs AEs	97 participants	—
Open Label Period (OL); Number of Participants Who Died, Experienced Adverse Events (AEs), Serious AEs, Drug Related AEs or SAEs and Discontinued Due to AEs SAEs	21 participants	—
Open Label Period (OL); Number of Participants Who Died, Experienced Adverse Events (AEs), Serious AEs, Drug Related AEs or SAEs and Discontinued Due to AEs All AEs Leading to Discontinuation	3 participants	—
Open Label Period (OL); Number of Participants Who Died, Experienced Adverse Events (AEs), Serious AEs, Drug Related AEs or SAEs and Discontinued Due to AEs Drug related AEs	49 participants	—
Open Label Period (OL); Number of Participants Who Died, Experienced Adverse Events (AEs), Serious AEs, Drug Related AEs or SAEs and Discontinued Due to AEs Drug related SAEs	11 participants	—

PRIMARY outcome

Timeframe: From start of study drug therapy in open-label period (Day 365) up to 56 days after the last dose of open-label period

Population: As treated analysis population: All treated participants who entered the open-label period and received at least one dose of study medication during open-label period.

An AE was defined as any new untoward medical occurrence or worsening of a pre-existing medical condition (even if not caused by the study drug). For this study, it was decided that AEs of particular importance were associated with the use of immunomodulatory agents. Number of participants with infections, malignant Neoplasms, pre-specified autoimmune disorders, acute-infusional AEs and peri-infusional AEs were recorded.

Outcome measures

Measure	Abatacept n=110 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
OL; Number of Participants With Significant AEs of Special Interest Infections	82 participants	—
OL; Number of Participants With Significant AEs of Special Interest Malignant neoplasms	1 participants	—
OL; Number of Participants With Significant AEs of Special Interest Pre-specified autoimmune disorders	4 participants	—
OL; Number of Participants With Significant AEs of Special Interest Acute-infusional AEs	3 participants	—
OL; Number of Participants With Significant AEs of Special Interest Peri-infusional AEs	15 participants	—

PRIMARY outcome

Timeframe: From start of study drug therapy in open-label period (Day 365) up to 56 days after the last dose of open-label period

Population: As treated analysis population: All treated participants who entered the open-label period and received at least one dose of study medication. Where "not evaluable" was recorded for "high" values (hemoglobin, hematocrit, erythrocytes) and has been presented as "0". n = number of participants with evaluable results (each arm respectively).

MAs are laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following hematology MA definitions specify the criteria for the data presented. Hemoglobin: >3 g/dL decrease from pre-treatment (pre-Rx) value; hematocrit: <0.75* pre-Rx value; erythrocyte count: <0.75* pre-Rx value; platelet count: <0.67* lower limit of normal (LLN) or >1.5* upper limit of normal (ULN) (or, if pre-Rx value <LLN, then <0.5* pre-Rx value or <100000/mm^3).

Outcome measures

Measure	Abatacept n=110 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
OL; Number of Participants With Marked Abnormalities (MAs) in Hematology: Hemoglobin, Hematocrit, Erythrocytes and Platelet Count Hemoglobin (n = 110)	2 participants	—
OL; Number of Participants With Marked Abnormalities (MAs) in Hematology: Hemoglobin, Hematocrit, Erythrocytes and Platelet Count Hematocrit (n = 110)	3 participants	—
OL; Number of Participants With Marked Abnormalities (MAs) in Hematology: Hemoglobin, Hematocrit, Erythrocytes and Platelet Count Erythrocytes (n = 110)	2 participants	—
OL; Number of Participants With Marked Abnormalities (MAs) in Hematology: Hemoglobin, Hematocrit, Erythrocytes and Platelet Count Platelet count (n = 108)	3 participants	—

PRIMARY outcome

Timeframe: From start of study drug therapy in open-label period (Day 365) up to 56 days after the last dose of open-label period

Population: As treated analysis population: All treated participants who entered the open-label period and received at least one dose of study medication during open-label period. Where "not evaluable" was recorded for either "low"(monocytes, basophils, eosinophils) or "high"(neutrophils) has been presented as "0".

MMAs are laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following hematology MA definitions specify the criteria for the data presented. Leukocytes: <0.75* LLN or >1.25* ULN (or, if pre-Rx value <LLN, then <0.8* pre-Rx or >ULN. If pre-Rx value >ULN, then >1.2* pre-Rx or <LLN; Neutrophils+bands (absolute): <1.00* 10^3 cells/microliter (c/uL); Lymphocytes (absolute): <0.75* 10^3 c/uL or >7.50* 10^3 c/uL; Monocytes (absolute): >2000/mm^3; Basophils (absolute): >0.40* 10^3 c/uL; Eosinophils (absolute): >0.75* 10^3 c/uL.

Outcome measures

Measure	Abatacept n=110 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
OL; Number of Participants With MAs in Hematology: Leukocytes, Neutrophils + Bands (Absolute), Lymphocytes (Absolute), Monocytes (Absolute), Basophils (Absolute) and Eosinophils (Absolute) Leukocytes	18 participants	—
OL; Number of Participants With MAs in Hematology: Leukocytes, Neutrophils + Bands (Absolute), Lymphocytes (Absolute), Monocytes (Absolute), Basophils (Absolute) and Eosinophils (Absolute) Neutrophils+bands (absolute)	6 participants	—
OL; Number of Participants With MAs in Hematology: Leukocytes, Neutrophils + Bands (Absolute), Lymphocytes (Absolute), Monocytes (Absolute), Basophils (Absolute) and Eosinophils (Absolute) Lymphocytes (absolute)	32 participants	—
OL; Number of Participants With MAs in Hematology: Leukocytes, Neutrophils + Bands (Absolute), Lymphocytes (Absolute), Monocytes (Absolute), Basophils (Absolute) and Eosinophils (Absolute) Monocytes (absolute)	0 participants	—
OL; Number of Participants With MAs in Hematology: Leukocytes, Neutrophils + Bands (Absolute), Lymphocytes (Absolute), Monocytes (Absolute), Basophils (Absolute) and Eosinophils (Absolute) Basophils (absolute)	0 participants	—
OL; Number of Participants With MAs in Hematology: Leukocytes, Neutrophils + Bands (Absolute), Lymphocytes (Absolute), Monocytes (Absolute), Basophils (Absolute) and Eosinophils (Absolute) Eosinophils (absolute)	3 participants	—

PRIMARY outcome

Timeframe: From start of study drug therapy in open-label period (Day 365) up to 56 days after the last dose of open-label period

Population: As treated analysis population: All treated participants who entered the open-label period and received at least one dose of study medication during open-label period. Where "not evaluable" was recorded for "low" values (ALP, AST, ALT, GGT, bilirubin, BUN, creatinine) and has been presented as "0".

MAs are laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following serum chemistry MA definitions specify MA criteria. ALP, GGT: >2* ULN (if pre-Rx >ULN, then >3* pre-Rx); AST, ALT: >3* ULN (if pre-Rx >ULN, then >4* pre-Rx). Bilirubin (total): >2* ULN (if pre-Rx >ULN, then >4* pre-Rx), BUN:>2* pre-Rx; Creatinine:>1.5* pre-Rx.

Outcome measures

Measure	Abatacept n=110 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
OL; Number of Participants With MAs in Serum Chemistry: Alkaline Phosphatase (ALP), Aspartate-aminotransferase (AST), Alanine-aminotransferase (ALT), Gamma-glutamyl Transferase (GGT), Bilirubin(Total), Blood Urea Nitrogen (BUN), Creatinine ALP	0 participants	—
OL; Number of Participants With MAs in Serum Chemistry: Alkaline Phosphatase (ALP), Aspartate-aminotransferase (AST), Alanine-aminotransferase (ALT), Gamma-glutamyl Transferase (GGT), Bilirubin(Total), Blood Urea Nitrogen (BUN), Creatinine AST	3 participants	—
OL; Number of Participants With MAs in Serum Chemistry: Alkaline Phosphatase (ALP), Aspartate-aminotransferase (AST), Alanine-aminotransferase (ALT), Gamma-glutamyl Transferase (GGT), Bilirubin(Total), Blood Urea Nitrogen (BUN), Creatinine ALT	4 participants	—
OL; Number of Participants With MAs in Serum Chemistry: Alkaline Phosphatase (ALP), Aspartate-aminotransferase (AST), Alanine-aminotransferase (ALT), Gamma-glutamyl Transferase (GGT), Bilirubin(Total), Blood Urea Nitrogen (BUN), Creatinine GGT	6 participants	—
OL; Number of Participants With MAs in Serum Chemistry: Alkaline Phosphatase (ALP), Aspartate-aminotransferase (AST), Alanine-aminotransferase (ALT), Gamma-glutamyl Transferase (GGT), Bilirubin(Total), Blood Urea Nitrogen (BUN), Creatinine Bilirubin (total)	0 participants	—
OL; Number of Participants With MAs in Serum Chemistry: Alkaline Phosphatase (ALP), Aspartate-aminotransferase (AST), Alanine-aminotransferase (ALT), Gamma-glutamyl Transferase (GGT), Bilirubin(Total), Blood Urea Nitrogen (BUN), Creatinine BUN	3 participants	—
OL; Number of Participants With MAs in Serum Chemistry: Alkaline Phosphatase (ALP), Aspartate-aminotransferase (AST), Alanine-aminotransferase (ALT), Gamma-glutamyl Transferase (GGT), Bilirubin(Total), Blood Urea Nitrogen (BUN), Creatinine Creatinine	7 participants	—

PRIMARY outcome

Timeframe: From start of study drug therapy in open-label period (Day 365) up to 56 days after the last dose of open-label period

Population: As treated analysis population: All treated participants who entered the open-label period and received at least one dose of study medication during open-label period.

MAs are laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following serum chemistry MA definitions specify MA criteria, Sodium (serum): <0.95x LLN or >1.05x ULN (if pre-Rx<LLN, then <0.95x pre-Rx or >ULN. If pre-Rx >ULN, then >1.05x pre-Rx or <LLN); Potassium (serum), Chloride (serum), protein (total): <0.9x LLN or >1.1xULN (if pre-Rx <LLN, then <0.9xpre-Rx or >ULN. If pre-Rx >ULN, then >1.1xpre-Rx or <LLN; Calcium (total): <0.8xLLN or >1.2xULN (if pre-Rx <LLN, then <0.75x pre-Rx or >ULN. If pre-Rx >ULN, then >1.25x pre-Rx or <LLN.

Outcome measures

Measure	Abatacept n=110 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
OL; Number of Participants With MAs in Serum Chemistry: Sodium (Serum), Potassium (Serum), Chloride (Serum), Calcium (Total), Protein (Total) Sodium (serum)	0 participants	—
OL; Number of Participants With MAs in Serum Chemistry: Sodium (Serum), Potassium (Serum), Chloride (Serum), Calcium (Total), Protein (Total) Potassium (serum)	7 participants	—
OL; Number of Participants With MAs in Serum Chemistry: Sodium (Serum), Potassium (Serum), Chloride (Serum), Calcium (Total), Protein (Total) Chloride (serum)	0 participants	—
OL; Number of Participants With MAs in Serum Chemistry: Sodium (Serum), Potassium (Serum), Chloride (Serum), Calcium (Total), Protein (Total) Calcium (total)	1 participants	—
OL; Number of Participants With MAs in Serum Chemistry: Sodium (Serum), Potassium (Serum), Chloride (Serum), Calcium (Total), Protein (Total) Protein (total)	4 participants	—

PRIMARY outcome

Timeframe: From start of study drug therapy in open-label period (Day 365) up to 56 days after the last dose of open-label period

Population: As treated analysis population: All treated participants who entered the open-label period and received at least one dose of study medication. Where "not evaluable" was recorded for either "low" (cholesterol, triglycerides) or "high" (albumin) has been presented as "0". n = number of participants with evaluable results (each arm respectively).

MAs are laboratory measurements marked as abnormal, as per pre-defined study criteria, at any study time point. The following serum chemistry MA definitions specify MA criteria, Glucose: <65 mg/dL or >220 mg/dL; Glucose (fasting serum): <0.8* LLN or >1.5 ULN (if pre-Rx <LLN, then <0.8* pre-Rx or >ULN. If pre-Rx >ULN, then >2.0* pre-Rx or <LLN; Albumin: <0.9* LLN (if pre-Rx <LLN, then <0.75 * pre-Rx); cholesterol (total): >2* pre-Rx; triglycerides: >=2.5* ULN, or if pre Rx>ULN then use >2.5* pre Rx; fasting triglycerides: >=2.0* ULN, or if pre Rx>ULN then use >2.0* pre Rx.

Outcome measures

Measure	Abatacept n=110 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
OL; Number of Participants With MAs in Serum Chemistry: Glucose (Serum), Glucose (Fasting Serum), Albumin, Cholesterol (Total), Triglycerides, Fasting Triglycerides Glucose (serum) (n = 110)	21 participants	—
OL; Number of Participants With MAs in Serum Chemistry: Glucose (Serum), Glucose (Fasting Serum), Albumin, Cholesterol (Total), Triglycerides, Fasting Triglycerides Glucose (fasting serum) (n = 55)	6 participants	—
OL; Number of Participants With MAs in Serum Chemistry: Glucose (Serum), Glucose (Fasting Serum), Albumin, Cholesterol (Total), Triglycerides, Fasting Triglycerides Albumin (n = 110)	6 participants	—
OL; Number of Participants With MAs in Serum Chemistry: Glucose (Serum), Glucose (Fasting Serum), Albumin, Cholesterol (Total), Triglycerides, Fasting Triglycerides Cholesterol (total) (n = 15)	0 participants	—
OL; Number of Participants With MAs in Serum Chemistry: Glucose (Serum), Glucose (Fasting Serum), Albumin, Cholesterol (Total), Triglycerides, Fasting Triglycerides Triglycerides (n = 10)	0 participants	—
OL; Number of Participants With MAs in Serum Chemistry: Glucose (Serum), Glucose (Fasting Serum), Albumin, Cholesterol (Total), Triglycerides, Fasting Triglycerides Triglycerides (fasting) (n = 9)	0 participants	—

PRIMARY outcome

Timeframe: From start of study drug therapy in open-label period (Day 365) up to 56 days after the last dose of open-label period

Population: As treated analysis population: all treated participants who entered the OL period and received at least 1 dose of study medication. Where "not evaluable" was recorded for "low" (protein, glucose, blood, leukocyte esterase, RBC, WBC) or "high"(GFR) values and presented as "0". n=number of participants with evaluable results (each arm respectively).

MAs are laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following definitions specify the criteria for MAs in urinalysis, Protein, glucose, blood, Leukocyte esterase, red blood cells (RBC), white blood cells (WBC): >=2+ (or, if value >=4, or if pre-Rx value = 0 or 0.5, then >= 2* or if pre-Rx value =1, then >=3, or if pre-Rx = 2 or 3, then >=4); protein (24 hour urine): >1000 mg/24 hrs and >=2* pre-Rx; Glomerular filtration rate (GFR): <=60 mL/min/1.73m^2 or > 15% change from baseline; Protein/creatinine ratio: > 100 mg/mmol.

Outcome measures

Measure	Abatacept n=110 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
OL; Number of Participants With MAs in Urinalysis Protein (n = 110)	12 participants	—
OL; Number of Participants With MAs in Urinalysis Glucose (n= 110)	0 participants	—
OL; Number of Participants With MAs in Urinalysis Blood (n = 110)	41 participants	—
OL; Number of Participants With MAs in Urinalysis Leukocyte esterase (n = 104)	28 participants	—
OL; Number of Participants With MAs in Urinalysis WBC (n = 105)	57 participants	—
OL; Number of Participants With MAs in Urinalysis RBC (n = 101)	35 participants	—
OL; Number of Participants With MAs in Urinalysis GFR (n = 110)	9 participants	—
OL; Number of Participants With MAs in Urinalysis Protein/creatinine ratio (n = 109)	10 participants	—

SECONDARY outcome

Timeframe: From start of corticosteroid taper to 6 months.

Population: All randomized and treated participants, grouped by the treatment randomized to (ITT).

SLE flares scored using BILAG:A:presence of =>1 serious;B:more moderate;C:mild symptomatic;D:prior activity,no current symptoms;E:organ that has never been involved.Calculated based on change during previous 4 weeks (1=improving,2=staying same,3=worsening,4=new).New SLE flare:first BILAG 'A' or 'B' event adjudicated to be flare following resolution of entry flare and/or start of prednisone/prednisone-equivalent taper.Inception treatment failure included (entry flare did not subside by Day 57/participant discontinued double-blind period before Day 29).

Outcome measures

Measure	Abatacept n=118 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=57 Participants Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
DB; Number of Participants With a New SLE Flare During the Initial 6 Months	75 Participants Interval 54.9 to 72.2	36 Participants Interval 50.6 to 75.7

SECONDARY outcome

Timeframe: From start of corticosteroid taper to Day 365

Population: All randomized and treated participants, grouped by the treatment randomized to (ITT).

SLE flares scored using BILAG:A:presence of =>1 serious;B:more moderate;C:mild symptomatic;D:prior activity,no current symptoms;E:organ that has never been involved.Calculated based on change during previous 4 weeks (1=improving,2=staying same,3=worsening,4=new).New SLE flare:BILAG 'A' or 'B' event adjudicated to be flare following resolution of entry flare and/or start of prednisone/prednisone-equivalent taper.Inception treatment failure included (entry flare did not subside by Day 57/participant discontinued double-blind period before Day 29).

Outcome measures

Measure	Abatacept n=118 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=57 Participants Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
DB; Total Number of New SLE Flares Each Participant Experienced None	24 Participants	10 Participants
DB; Total Number of New SLE Flares Each Participant Experienced 1	47 Participants	21 Participants
DB; Total Number of New SLE Flares Each Participant Experienced 2	21 Participants	10 Participants
DB; Total Number of New SLE Flares Each Participant Experienced >=3	17 Participants	11 Participants
DB; Total Number of New SLE Flares Each Participant Experienced Inception treatment failure	9 Participants	5 Participants

SECONDARY outcome

Timeframe: From start of corticosteroid taper to confirmation of disease flare or the end of double-blind period

Population: All randomized and treated participants, grouped by the treatment randomized to (ITT).

Elapsed days between start of corticosteroid taper & first day of flare.Scored using BILAG:A:presence of =>1 serious;B:more moderate;C:mild symptomatic;D:prior activity,no current symptoms;E:organ that has never been involved.Calculated based on change during previous 4 weeks (1=improving,2=staying same,3=worsening,4=new).New SLE flare:first BILAG 'A' or 'B' event adjudicated to be flare following resolution of entry flare and/or start of corticosteroid taper.Inception treatment failure included (entry flare did not subside by Day 57/participant discontinued double-blind period before Day 29).

Outcome measures

Measure	Abatacept n=118 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=57 Participants Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
DB; Median Number of Days to the First Occurrence of a New SLE Flare	107.0 Days Interval 81.0 to 125.0	92.0 Days Interval 58.0 to 150.0

SECONDARY outcome

Timeframe: From start of study drug treatment to Day 365

Population: All randomized and treated participants who were available for analysis, grouped by the treatment randomized to (ITT).

SLICC/ACR score or damage index is a measure of cumulative damage due to Systemic Lupus Erythematosus (SLE). Damage is defined as non-reversible change (not related to active inflammation) occurring since onset of lupus, ascertained by clinical assessment and present for at least 6 months. A score of 0=no damage, early damage is defined as ≥1. The total maximum score is 48, and increasing score indicates increasing disease severity.

Outcome measures

Measure	Abatacept n=107 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=47 Participants Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
DB; Number of Participants With a Change in the SLICC/ACR Damage Index at 1 Year Compared to Baseline No change	101 participants Interval 90.0 to 98.8	44 participants Interval 86.6 to 100.0
DB; Number of Participants With a Change in the SLICC/ACR Damage Index at 1 Year Compared to Baseline Increased 1	3 participants Interval 0.6 to 8.0	2 participants Interval 0.5 to 14.5
DB; Number of Participants With a Change in the SLICC/ACR Damage Index at 1 Year Compared to Baseline Increased >1	3 participants Interval 0.6 to 8.0	1 participants Interval 0.1 to 11.3

SECONDARY outcome

Timeframe: Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier

Population: All participants given study drug during the double-blind period ("As Treated"). The AEs represented here include SAEs, which are not included in the AE count represented in the AE xml upload section. As such, these numbers may not match.

AEs: any new untoward medical occurrences/worsening of pre-existing medical condition, whether or not related to study drug. SAE: any AE that resulted in death; was life threatening; resulted in persistent/significant disability/incapacity; resulted in/prolonged an existing in-patient hospitalization; was a congenital anomaly/birth defect; or was an overdose. Drug-related AEs: events with a certain; probable; possible; or missing relationship to the study therapy. Participants who discontinued the study due to an AE were recorded.

Outcome measures

Measure	Abatacept n=121 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=59 Participants Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
DB; Number of Participants Who Died, Experienced AEs, Other SAEs or Discontinuations Due to AEs, Drug Related AEs Deaths	0 participants	0 participants
DB; Number of Participants Who Died, Experienced AEs, Other SAEs or Discontinuations Due to AEs, Drug Related AEs AEs	110 participants	54 participants
DB; Number of Participants Who Died, Experienced AEs, Other SAEs or Discontinuations Due to AEs, Drug Related AEs SAEs	24 participants	4 participants
DB; Number of Participants Who Died, Experienced AEs, Other SAEs or Discontinuations Due to AEs, Drug Related AEs All AEs Leading to Discontinuation	10 participants	3 participants
DB; Number of Participants Who Died, Experienced AEs, Other SAEs or Discontinuations Due to AEs, Drug Related AEs Drug related AEs	59 participants	28 participants

SECONDARY outcome

Timeframe: Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier

Population: All participants given study drug during the double-blind period ("As Treated").Participants grouped for randomized treatments, except where different treatment taken for entire double-blind period (which will instead be presented by first treatment actually received).

An AE was defined as any new untoward medical occurrence or worsening of a pre-existing medical condition (even if not caused by the study drug). For this study, AEs of special interest were associated with the use of immunomodulatory agents. Number of participants with infections, malignant neoplasms, pre-specified autoimmune disorders, acute infusional AEs and peri-infusional AEs were recorded.

Outcome measures

Measure	Abatacept n=121 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=59 Participants Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
DB; Number of Participants With Significant AEs of Special Interest Peri-infusional AEs	27 participants	13 participants
DB; Number of Participants With Significant AEs of Special Interest Infections	71 participants	38 participants
DB; Number of Participants With Significant AEs of Special Interest Malignant neoplasms	1 participants	0 participants
DB; Number of Participants With Significant AEs of Special Interest Pre-specified autoimmune disorders	4 participants	2 participants
DB; Number of Participants With Significant AEs of Special Interest Acute-infusional AEs	5 participants	5 participants

SECONDARY outcome

Timeframe: Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier

Population: All participants given study drug during the double-blind period (As Treated) where "not evaluable" was recorded for "high" values (hemoglobin, hematocrit and erythrocytes)has been presented as "0". n=number of participants with evaluable results (each arm respectively).

MAs are laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following hematology MA definitions specify the criteria for the data presented. Hemoglobin: >3 g/dL decrease from pre-treatment (pre-Rx) value; hematocrit: <0.75* pre-Rx value; erythrocyte count: <0.75* pre-Rx value; platelet count: <0.67* LLN or >1.5* ULN (or, if pre-Rx value <LLN, then <0.5* pre-Rx value or <100000/mm^3).

Outcome measures

Measure	Abatacept n=120 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=58 Participants Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
DB; Number of Participants With MAs in Hematology: Hemoglobin, Hematocrit, Erythrocytes and Platelet Count Hemoglobin (n = 120, 58)	1 participants	1 participants
DB; Number of Participants With MAs in Hematology: Hemoglobin, Hematocrit, Erythrocytes and Platelet Count Hematocrit (n=120, 58)	1 participants	1 participants
DB; Number of Participants With MAs in Hematology: Hemoglobin, Hematocrit, Erythrocytes and Platelet Count Erythrocytes (n=120, 58)	1 participants	1 participants
DB; Number of Participants With MAs in Hematology: Hemoglobin, Hematocrit, Erythrocytes and Platelet Count Platelet count (n= 118, 58)	3 participants	0 participants

SECONDARY outcome

Timeframe: Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier

Population: All participants given study drug during the double-blind period ("As Treated") where "not evaluable" was recorded for either "low"(monocytes, basophils and eosinophils) or "high" values(neutrophils)has been presented as "0".n=number of participants with evaluable results (each arm respectively).

MAs are laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following hematology MA definitions specify the criteria for the data presented. Leukocytes: <0.75* LLN or >1.25* ULN (or, if pre-Rx value <LLN, then <0.8* pre-Rx or >ULN. If pre-Rx value >ULN, then >1.2* pre-Rx or <LLN; Neutrophils+bands (absolute): <1.00* 10^3 cells/microliter (c/uL); Lymphocytes (absolute): <0.75* 10^3 c/uL or >7.50* 10^3 c/uL; Monocytes (absolute): >2000/mm^3; Basophils (absolute): >0.40* 10^3 c/uL; Eosinophils (absolute): >0.75* 10^3 c/uL.

Outcome measures

Measure	Abatacept n=120 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=59 Participants Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
DB; Number of Participants With MAs in Hematology: Leukocytes, Neutrophils + Bands (Absolute), Lymphocytes (Absolute), Monocytes (Absolute), Basophils (Absolute) and Eosinophils (Absolute) Basophils (absolute) (n = 120, 59)	0 participants	0 participants
DB; Number of Participants With MAs in Hematology: Leukocytes, Neutrophils + Bands (Absolute), Lymphocytes (Absolute), Monocytes (Absolute), Basophils (Absolute) and Eosinophils (Absolute) Eosinophils (absolute) (n = 120, 59)	6 participants	2 participants
DB; Number of Participants With MAs in Hematology: Leukocytes, Neutrophils + Bands (Absolute), Lymphocytes (Absolute), Monocytes (Absolute), Basophils (Absolute) and Eosinophils (Absolute) Leukocytes (n = 120, 58)	26 participants	11 participants
DB; Number of Participants With MAs in Hematology: Leukocytes, Neutrophils + Bands (Absolute), Lymphocytes (Absolute), Monocytes (Absolute), Basophils (Absolute) and Eosinophils (Absolute) Neutrophils+bands (absolute) (n = 120, 59)	8 participants	2 participants
DB; Number of Participants With MAs in Hematology: Leukocytes, Neutrophils + Bands (Absolute), Lymphocytes (Absolute), Monocytes (Absolute), Basophils (Absolute) and Eosinophils (Absolute) Lymphocytes (absolute) (n = 120, 59)	46 participants	30 participants
DB; Number of Participants With MAs in Hematology: Leukocytes, Neutrophils + Bands (Absolute), Lymphocytes (Absolute), Monocytes (Absolute), Basophils (Absolute) and Eosinophils (Absolute) Monocytes (absolute) (n = 120, 59)	1 participants	0 participants

SECONDARY outcome

Timeframe: Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier

Population: All participants given study drug during the double-blind period ("As Treated") where "not evaluable" was recorded for "low" values (all parameters) and has been presented as "0". n=number of participants with evaluable results (each arm respectively).

MAs are laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following serum chemistry MA definitions specify MA criteria. ALP, GGT: >2* ULN (if pre-Rx >ULN, then >3* pre-Rx); AST, ALT: >3* ULN (if pre-Rx >ULN, then >4* pre-Rx). Bilirubin (total): >2* ULN (if pre-Rx >ULN, then >4* pre-Rx), BUN:>2* pre-Rx; Creatinine:>1.5* pre-Rx.

Outcome measures

Measure	Abatacept n=120 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=59 Participants Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
DB: Number of Participants With MAs in Serum Chemistry: ALP, AST, ALT, GGT, Bilirubin (Total), BUN and Creatinine Bilirubin (total) (n = 120, 59)	0 participants	0 participants
DB: Number of Participants With MAs in Serum Chemistry: ALP, AST, ALT, GGT, Bilirubin (Total), BUN and Creatinine ALP (n = 120, 59)	2 participants	0 participants
DB: Number of Participants With MAs in Serum Chemistry: ALP, AST, ALT, GGT, Bilirubin (Total), BUN and Creatinine AST (n = 120, 59)	3 participants	0 participants
DB: Number of Participants With MAs in Serum Chemistry: ALP, AST, ALT, GGT, Bilirubin (Total), BUN and Creatinine ALT (n = 120, 59)	2 participants	0 participants
DB: Number of Participants With MAs in Serum Chemistry: ALP, AST, ALT, GGT, Bilirubin (Total), BUN and Creatinine GGT (n = 120, 59)	3 participants	3 participants
DB: Number of Participants With MAs in Serum Chemistry: ALP, AST, ALT, GGT, Bilirubin (Total), BUN and Creatinine BUN (n = 120, 59)	4 participants	3 participants
DB: Number of Participants With MAs in Serum Chemistry: ALP, AST, ALT, GGT, Bilirubin (Total), BUN and Creatinine Creatinine (n = 120, 59)	6 participants	4 participants

SECONDARY outcome

Timeframe: Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier

Population: All participants given study drug during the double-blind period ("As Treated").n=number of participants with evaluable results (each arm respectively).

MAs are laboratory measurements marked as abnormal as per pre-defined study criteria, at any study time point. The following serum chemistry MA definitions specify MA criteria, Sodium (serum): <0.95* LLN or >1.05* ULN (if pre-Rx <LLN, then <0.95* pre-Rx or >ULN. If pre-Rx >ULN, then >1.05* pre-Rx or <LLN); Potassium (serum), Chloride (serum), protein (total): <0.9* LLN or >1.1* ULN (if pre-Rx <LLN, then <0.9* pre-Rx or >ULN. If pre-Rx >ULN, then >1.1* pre-Rx or <LLN; Calcium (total): <0.8* LLN or >1.2* ULN (if pre-Rx <LLN, then <0.75* pre-Rx or >ULN. If pre-Rx >ULN, then >1.25* pre-Rx or <LLN.

Outcome measures

Measure	Abatacept n=120 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=59 Participants Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
DB; Number of Participants With MAs in Serum Chemistry: Sodium (Serum), Potassium (Serum), Chloride (Serum), Calcium (Total),Protein (Total) Sodium (serum) (n = 120, 59)	1 participants	0 participants
DB; Number of Participants With MAs in Serum Chemistry: Sodium (Serum), Potassium (Serum), Chloride (Serum), Calcium (Total),Protein (Total) Potassium (serum) (n = 120, 59)	1 participants	1 participants
DB; Number of Participants With MAs in Serum Chemistry: Sodium (Serum), Potassium (Serum), Chloride (Serum), Calcium (Total),Protein (Total) Chloride (serum) (n = 120, 59)	0 participants	0 participants
DB; Number of Participants With MAs in Serum Chemistry: Sodium (Serum), Potassium (Serum), Chloride (Serum), Calcium (Total),Protein (Total) Calcium (total) (n= 120, 59)	0 participants	0 participants
DB; Number of Participants With MAs in Serum Chemistry: Sodium (Serum), Potassium (Serum), Chloride (Serum), Calcium (Total),Protein (Total) Protein (total) (n = 120, 59)	1 participants	0 participants

SECONDARY outcome

Timeframe: Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier

Population: "All participants given study drug during the double-blind period ("As Treated") where "not evaluable" was recorded for either "low" or "high" values (albumin, cholesterol, triglycerides) has been presented as "0".n=number of participants with evaluable results (each arm respectively).

MAs are laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following serum chemistry MA definitions specify MA criteria, Glucose: <65 mg/dl or >220 mg/dl; Glucose (fasting serum): <0.8* LLN or >1.5 ULN (if pre-Rx <LLN, then <0.8* pre-Rx or >ULN. If pre-Rx >ULN, then >2.0* pre-Rx or <LLN; Albumin: <0.9* LLN (if pre-Rx <LLN, then <0.75 * pre-Rx); cholesterol (total): >2* pre-Rx; triglycerides: >=2.5* ULN, or if pre Rx>ULN then use >2.5* pre Rx; fasting triglycerides: >=2.0* ULN, or if pre Rx>ULN then use >2.0* pre Rx.

Outcome measures

Measure	Abatacept n=120 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=59 Participants Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
DB; Number of Participants With MAs in Serum Chemistry: Glucose (Serum), Glucose (Fasting Serum), Albumin, Cholesterol (Total), Triglycerides, Fasting Triglycerides Glucose (serum) (n = 120, 59)	27 participants	10 participants
DB; Number of Participants With MAs in Serum Chemistry: Glucose (Serum), Glucose (Fasting Serum), Albumin, Cholesterol (Total), Triglycerides, Fasting Triglycerides Glucose, fasting (n = 77, 37)	5 participants	1 participants
DB; Number of Participants With MAs in Serum Chemistry: Glucose (Serum), Glucose (Fasting Serum), Albumin, Cholesterol (Total), Triglycerides, Fasting Triglycerides Albumin (n = 120, 59)	4 participants	1 participants
DB; Number of Participants With MAs in Serum Chemistry: Glucose (Serum), Glucose (Fasting Serum), Albumin, Cholesterol (Total), Triglycerides, Fasting Triglycerides Cholesterol (total) (n = 118, 58)	0 participants	0 participants
DB; Number of Participants With MAs in Serum Chemistry: Glucose (Serum), Glucose (Fasting Serum), Albumin, Cholesterol (Total), Triglycerides, Fasting Triglycerides Triglycerides (n = 75, 36)	0 participants	0 participants
DB; Number of Participants With MAs in Serum Chemistry: Glucose (Serum), Glucose (Fasting Serum), Albumin, Cholesterol (Total), Triglycerides, Fasting Triglycerides Triglycerides (fasting) (n = 64, 34)	0 participants	0 participants

SECONDARY outcome

Timeframe: Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier

Population: All participants given study drug during the double-blind period ("As Treated") where "not evaluable" was recorded for "low" (protein, glucose, blood, leukocyte esterase, RBC, WBC) or "high" (GFR) values has been presented as "0". n=number of participants with evaluable results (each arm respectively).

MAs are laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following definitions specify the criteria for MAs in urinalysis, Protein, glucose, blood, Leukocyte esterase, RBC, WBC: >=2+ (or, if value >=4, or if pre-Rx value = 0 or 0.5, then >= 2* pre-Rx, or if pre-Rx value =1, then >=3, or if pre-Rx = 2 or 3, then >=4); protein (24 hour urine): >1000 mg/24 hrs and >=2* pre-Rx; GFR: <=60 mL/min/1.73m^2 or > 15% change from baseline; Protein/creatinine ratio: > 100 mg/mmol.

Outcome measures

Measure	Abatacept n=120 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=58 Participants Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
DB; Number of Participants With MAs in Urinalysis Protein (n = 120, 58)	15 participants	9 participants
DB; Number of Participants With MAs in Urinalysis Glucose (n = 120, 58)	1 participants	2 participants
DB; Number of Participants With MAs in Urinalysis Blood (n = 120, 58)	39 participants	18 participants
DB; Number of Participants With MAs in Urinalysis Leukocyte esterase (n = 107, 51)	23 participants	8 participants
DB; Number of Participants With MAs in Urinalysis RBC (n = 107, 55)	38 participants	16 participants
DB; Number of Participants With MAs in Urinalysis WBC (n = 115, 54)	61 participants	26 participants
DB; Number of Participants With MAs in Urinalysis Protein, 24 hours (n = 89, 40)	4 participants	1 participants
DB; Number of Participants With MAs in Urinalysis GFR (n = 120, 59)	7 participants	4 participants
DB; Number of Participants With MAs in Urinalysis Protein/creatinine ratio (n = 119, 58)	11 participants	4 participants

SECONDARY outcome

Timeframe: Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier

Population: All participants given study drug during the double-blind period ("As Treated"). Significant vital signs and physical examination findings are reported in the AE tables. Symptoms related to lupus were collected in British Isles Lupus Assessment Group (BILAG) assessments.

Vital signs assessments and physical examination were conducted throughout the study. Vital signs assessments included body temperature, respiratory rate, blood pressure (systolic and diastolic) and heart rate. The investigator used his/her clinical judgment to decide whether or not abnormalities in vital signs or physical examination were clinically meaningful.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From Day 1 to Day 365

Population: Participants who received abatacept and for whom baseline and at least one additional measurement during double-blind period were available.

Electrochemiluminescence (ECL) immunoassay based on Meso Scale Discovery (MSD) technology was used to detect antibodies specific for CTLA4-T and for abatacept.

Outcome measures

Measure	Abatacept n=121 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
DB; Number of Participants With Antibodies Specific for CTLA4-T and Abatacept, Following Abatacept Treatment	2 participants	—

SECONDARY outcome

Timeframe: From start of study drug therapy in open-label period (Day 365), Day 393, 421, 449 and every 28 days thereafter till Day 729.

Population: As treated analysis population: All treated participants who entered the open-label period and received at least one dose of study medication during open-label period.

SLE flares scored using BILAG:A:presence of =>1 serious lupus features;B:more moderate features;C:mild symptomatic features;D:prior activity with no current symptoms due to active lupus;E:an organ that has never been involved.BILAG scores based on degrees of change in clinical features (1=improving,2=staying the same,3=worsening,4=new).New SLE flare means new BILAG A/B features in any organ system.Based on the recommendation of the Data Monitoring Committee, open-label period terminated, as failed to meet primary outcome measure for double-blind period/increase in SAEs in abatacept group.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From start of study drug therapy in open-label period (Day 365) and on Day 729.

Population: As treated analysis population: All treated participants who entered the open-label period and received at least one dose of study medication during open-label period.

SLICC/ACR damage index:measure of cumulative damage due to SLE.Damage=non-reversible change occurring since onset of lupus,ascertained by clinical assessment & present for =>6 months.Scores of SLICC/ACR index:1:single episode;2:repeated episodes at least 6 months apart.Change in score from baseline to 1 year presented as:no change,increase 1 (an increase in score of 1),increase >1 (an increase in score of >1).Based on recommendation of Data Monitoring Committee, open-label period terminated, as failed to meet primary outcome measure for double-blind period/increase in SAEs in abatacept group.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From start of study drug therapy in open-label period (Day 365), Day 393, 421, 449 and every 28 days thereafter till Day 729.

Population: As treated analysis population: All treated participants who entered the open-label period and received at least one dose of study medication during open-label period.

Total number of BILAG A flares in any organ system after steroid tapering = new BILAG A features in any organ system. Scores defined as follows: None: participants with no BILAG A flare; 1: participants with 1 BILAG A flare or participants who discontinued without a new BILAG A flare were imputed as having one event. 2: participants with 2 BILAG A flares; 3 or >3: participants with 3 or more BILAG A flares.Based on recommendation of Data Monitoring Committee, open-label period terminated, as failed to meet primary outcome measure for double-blind period/increase in SAEs in abatacept group.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From start of study drug therapy in open-label period (Day 365), Day 393, 421, 449 and every 28 days thereafter till Day 729.

Population: As treated analysis population: All treated participants who entered the open-label period and received at least one dose of study medication during open-label period.

Total exposure to glucocorticosteroid was measured by the total prednisone or prednisone equivalent AUC. Based on the recommendation of the Data Monitoring Committee, the open-label, long-term extension period was terminated by the sponsor, for failure to meet the primary outcome measure for the double-blind period and because of an increase in SAEs in the abatacept treatment group. As such, these data were not analyzed.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: After the first dose of open-label period

Population: Immunogenicity analysis population: participants who received abatacept and for whom baseline and at least one additional measurement during the open-label period were available.

MSD technology was used to detect antibodies specific for CTLA4-T and for abatacept.

Outcome measures

Measure	Abatacept n=108 Participants Participants were administered intravenous (iv) infusions of abatacept (10 mg/kg) over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
OL; Number of Participants With Antibodies Specific for CTLA4-T and Abatacept, Following Abatacept Treatment	30 participants	—

Adverse Events

Abatacept

Serious events: 24 serious events

Other events: 90 other events

Deaths: 0 deaths

Placebo

Serious events: 4 serious events

Other events: 41 other events

Deaths: 0 deaths

Serious adverse events

Measure	Abatacept n=121 participants at risk Participants were administered abatacept (10 mg/kg) IV over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=59 participants at risk Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
Psychiatric disorders DEPRESSION	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Cardiac disorders PERICARDITIS	1.7% 2/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Vascular disorders LUPUS VASCULITIS	0.00% 0/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	1.7% 1/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Psychiatric disorders PSYCHOTIC DISORDER	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	1.7% 1/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Immune system disorders HYPERSENSITIVITY	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Immune system disorders DRUG HYPERSENSITIVITY	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Nervous system disorders HEADACHE	0.00% 0/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	1.7% 1/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Nervous system disorders POLYNEUROPATHY	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Nervous system disorders ACUTE POLYNEUROPATHY	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Gastrointestinal disorders HAEMATEMESIS	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Gastrointestinal disorders GASTRIC ULCER	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Gastrointestinal disorders ABDOMINAL PAIN	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Gastrointestinal disorders PERITONITIS LUPUS	0.00% 0/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	1.7% 1/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Infections and infestations BRONCHITIS	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Infections and infestations DIVERTICULITIS	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Infections and infestations GASTROENTERITIS	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Infections and infestations BRONCHOPNEUMONIA	0.00% 0/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	1.7% 1/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Renal and urinary disorders LUPUS NEPHRITIS	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Renal and urinary disorders GLOMERULONEPHRITIS	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Renal and urinary disorders MESANGIOPROLIFERATIVE GLOMERULONEPHRITIS	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Metabolism and nutrition disorders DEHYDRATION	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Blood and lymphatic system disorders ANAEMIA	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Skin and subcutaneous tissue disorders ANGIOEDEMA	0.00% 0/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	1.7% 1/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Injury, poisoning and procedural complications ANKLE FRACTURE	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Injury, poisoning and procedural complications GUN SHOT WOUND	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Musculoskeletal and connective tissue disorders ARTHRITIS	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Musculoskeletal and connective tissue disorders COSTOCHONDRITIS	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Musculoskeletal and connective tissue disorders MUSCULOSKELETAL CHEST PAIN	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Musculoskeletal and connective tissue disorders SYSTEMIC LUPUS ERYTHEMATOSUS	2.5% 3/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	1.7% 1/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Respiratory, thoracic and mediastinal disorders ALVEOLITIS	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Respiratory, thoracic and mediastinal disorders PLEURAL EFFUSION	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
General disorders PYREXIA	2.5% 3/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
General disorders CHEST PAIN	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
General disorders FACE OEDEMA	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
General disorders OEDEMA PERIPHERAL	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.

Other adverse events

Measure	Abatacept n=121 participants at risk Participants were administered abatacept (10 mg/kg) IV over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. All participants received a dose based on screening visit weight. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg once daily (OD). A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for British Isles Lupus Assessment Group (BILAG) "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.	Placebo n=59 participants at risk Participants were administered iv infusions of either dextrose 5% solution or normal saline (NS) at a constant rate over approximately 30 minutes on Days 1, 15, 29 and every 28 days thereafter up to and including Day 337. Prednisone or prednisone equivalent was administered at an initial oral dose of 30 mg OD. A standardized prednisone or prednisone equivalent taper procedure was followed whenever the participant's clinical features qualified for BILAG "C" or "D" status after Day 29. Participants who completed the double-blind period were eligible for the open-label long-term extension period, where all participants were reallocated to abatacept (regardless of randomized treatment in the double-blind period) according to body weight at study entry. Infusions continued every 28 days until abatacept was marketed for SLE or the drug development program discontinued.
Cardiac disorders PALPITATIONS	1.7% 2/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	6.8% 4/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Vascular disorders HYPERTENSION	3.3% 4/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	5.1% 3/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Psychiatric disorders INSOMNIA	8.3% 10/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	8.5% 5/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Psychiatric disorders DEPRESSION	5.8% 7/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	5.1% 3/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Nervous system disorders HEADACHE	20.7% 25/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	16.9% 10/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Nervous system disorders DIZZINESS	5.0% 6/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	8.5% 5/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Gastrointestinal disorders NAUSEA	9.9% 12/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	6.8% 4/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Gastrointestinal disorders DIARRHOEA	11.6% 14/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	6.8% 4/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Gastrointestinal disorders CONSTIPATION	1.7% 2/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	5.1% 3/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Gastrointestinal disorders ABDOMINAL PAIN	9.1% 11/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Gastrointestinal disorders ABDOMINAL PAIN UPPER	5.8% 7/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	8.5% 5/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Infections and infestations INFLUENZA	5.8% 7/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	5.1% 3/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Infections and infestations SINUSITIS	6.6% 8/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	6.8% 4/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Infections and infestations BRONCHITIS	5.8% 7/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	6.8% 4/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Infections and infestations PHARYNGITIS	2.5% 3/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	6.8% 4/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Infections and infestations GASTROENTERITIS	5.8% 7/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	3.4% 2/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Infections and infestations NASOPHARYNGITIS	2.5% 3/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	11.9% 7/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Infections and infestations URINARY TRACT INFECTION	10.7% 13/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	8.5% 5/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Infections and infestations UPPER RESPIRATORY TRACT INFECTION	20.7% 25/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	15.3% 9/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Skin and subcutaneous tissue disorders ACNE	5.8% 7/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	0.00% 0/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Skin and subcutaneous tissue disorders RASH	3.3% 4/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	5.1% 3/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Skin and subcutaneous tissue disorders PRURITUS	3.3% 4/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	5.1% 3/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Musculoskeletal and connective tissue disorders BACK PAIN	12.4% 15/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	8.5% 5/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Musculoskeletal and connective tissue disorders ARTHRALGIA	9.1% 11/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	6.8% 4/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Musculoskeletal and connective tissue disorders MUSCLE SPASMS	0.83% 1/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	6.8% 4/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Respiratory, thoracic and mediastinal disorders COUGH	8.3% 10/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	8.5% 5/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Respiratory, thoracic and mediastinal disorders NASAL CONGESTION	2.5% 3/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	5.1% 3/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
Respiratory, thoracic and mediastinal disorders PHARYNGOLARYNGEAL PAIN	9.9% 12/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	3.4% 2/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.
General disorders CHEST PAIN	5.8% 7/121 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.	6.8% 4/59 • Events recorded at each participant encounter, from start of study drug therapy up to Day 337, including up to 56 days after the last dose or up to the first dose of open-label, whichever occurred earlier.

Additional Information

BMS Study Director

Bristol-Myers Squibb

Email: Clinical.Trials@bms.com

Results disclosure agreements

• Principal investigator is a sponsor employee Bristol-Myers Squibb Co. agreements with investigators vary; constant is our right to embargo communications regarding trial results prior to public release for a period ≤60 days from submittal for review. We will not prohibit investigators from publishing, but will prohibit the disclosure of previously undisclosed confidential information other than study results, and request postponement of single-center publications until after disclosure of the clinical trial's primary publication.
• Publication restrictions are in place

Restriction type: OTHER