Trial Outcomes & Findings for A Study of Abatacept in Patients With Active Ulcerative Colitis (NCT NCT00410410)

Last Updated: 2015-03-24

Results Overview

The Mayo Scoring system ranges from 0 - 12 points and is a composite index consisting of 4 disease variables (stool frequency, rectal bleeding, endoscopy evaluation, and Physician's Global Assessment). Higher Mayo scores indicate greater severity of disease. A clinical response is defined as a reduction from baseline in the Mayo score of ≥ 3 points and ≥ 30%, with an accompanying decrease in the rectal bleeding subscore of ≥ 1 point or absolute rectal bleeding subscore of ≤ 1 point.

Recruitment status

COMPLETED

Study phase

PHASE3

Target enrollment

591 participants

Primary outcome timeframe

Week 12 (Day IP-85)

Results posted on

2015-03-24

Participant Flow

In this study, a first cohort (Induction Period First Cohort, IP1C) of 490 participants was randomized and used for analysis of the primary endpoint. Following randomization of IP1C, a second cohort (IP2C) of 146 participants was randomized to provide a sufficient number of participants for the Maintenance Period.

Participant milestones

Participant milestones
Measure	Induction Period Cohort 1 (IP1C)-Abatacept (ABA) 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29, and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29, and IP-57 at a dose of \~10 mg/kg (weight-tiered).	ABA ~10 mg/kg, Maintenance Period (MP) During MP, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered) every 28 days beginning Day MP-1.	Placebo, MP During the MP, placebo was administered IV every 28 days beginning Day MP-1 through Day MP-337.	ABA ~10 mg/kg, Open-Label Period (OL) During OL, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered) every 28 days beginning Day OL-1.
Induction Period (IP) STARTED	141	139	70	140	51	50	0	0	0
Induction Period (IP) COMPLETED	106	104	53	120	19	21	0	0	0
Induction Period (IP) NOT COMPLETED	35	35	17	20	32	29	0	0	0
Maintenance Period (MP) STARTED	0	0	0	0	0	0	65	66	0
Maintenance Period (MP) COMPLETED	0	0	0	0	0	0	15	11	0
Maintenance Period (MP) NOT COMPLETED	0	0	0	0	0	0	50	55	0
Open-Label Period (OL) STARTED	0	0	0	0	0	0	0	0	349
Open-Label Period (OL) COMPLETED	0	0	0	0	0	0	0	0	0
Open-Label Period (OL) NOT COMPLETED	0	0	0	0	0	0	0	0	349

Reasons for withdrawal

Reasons for withdrawal
Measure	Induction Period Cohort 1 (IP1C)-Abatacept (ABA) 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29, and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29, and IP-57 at a dose of \~10 mg/kg (weight-tiered).	ABA ~10 mg/kg, Maintenance Period (MP) During MP, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered) every 28 days beginning Day MP-1.	Placebo, MP During the MP, placebo was administered IV every 28 days beginning Day MP-1 through Day MP-337.	ABA ~10 mg/kg, Open-Label Period (OL) During OL, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered) every 28 days beginning Day OL-1.
Induction Period (IP) Death	1	0	0	0	0	0	0	0	0
Induction Period (IP) Adverse Event	3	4	2	4	1	0	0	0	0
Induction Period (IP) Lack of Efficacy	26	24	8	8	7	7	0	0	0
Induction Period (IP) Lost to Follow-up	2	2	2	3	0	1	0	0	0
Induction Period (IP) Withdrawal by Subject	3	5	3	5	2	0	0	0	0
Induction Period (IP) Subject No Longer Meets Study Criteria	0	0	1	0	0	0	0	0	0
Induction Period (IP) Administrative Reason By Sponsor	0	0	0	0	22	21	0	0	0
Induction Period (IP) Other	0	0	1	0	0	0	0	0	0
Maintenance Period (MP) Death	0	0	0	0	0	0	1	0	0
Maintenance Period (MP) Adverse Event	0	0	0	0	0	0	1	3	0
Maintenance Period (MP) Lack of Efficacy	0	0	0	0	0	0	25	24	0
Maintenance Period (MP) Lost to Follow-up	0	0	0	0	0	0	1	2	0
Maintenance Period (MP) Withdrawal by Subject	0	0	0	0	0	0	1	1	0
Maintenance Period (MP) Administrative Reason By Sponsor	0	0	0	0	0	0	21	25	0
Open-Label Period (OL) Death	0	0	0	0	0	0	0	0	1
Open-Label Period (OL) Adverse Event	0	0	0	0	0	0	0	0	10
Open-Label Period (OL) Lack of Efficacy	0	0	0	0	0	0	0	0	161
Open-Label Period (OL) Lost to Follow-up	0	0	0	0	0	0	0	0	4
Open-Label Period (OL) Withdrawal by Subject	0	0	0	0	0	0	0	0	20
Open-Label Period (OL) Pregnancy	0	0	0	0	0	0	0	0	1
Open-Label Period (OL) Administrative Reason By Sponsor	0	0	0	0	0	0	0	0	145
Open-Label Period (OL) Other	0	0	0	0	0	0	0	0	7

Baseline Characteristics

A Study of Abatacept in Patients With Active Ulcerative Colitis

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Induction Period Cohort 1 (IP1C)-ABA 30/~10 mg/kg n=141 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=139 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=70 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=140 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg n=51 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP2C-ABA ~10 mg/kg n=50 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	Total n=591 Participants Total of all reporting groups
Age, Customized <30 years	26 participants n=5 Participants	23 participants n=7 Participants	18 participants n=5 Participants	34 participants n=4 Participants	12 participants n=21 Participants	4 participants n=10 Participants	117 participants n=115 Participants
Age, Customized 30-50 years	70 participants n=5 Participants	84 participants n=7 Participants	35 participants n=5 Participants	73 participants n=4 Participants	30 participants n=21 Participants	32 participants n=10 Participants	324 participants n=115 Participants
Age, Customized >50 years	45 participants n=5 Participants	32 participants n=7 Participants	17 participants n=5 Participants	33 participants n=4 Participants	9 participants n=21 Participants	14 participants n=10 Participants	150 participants n=115 Participants
Sex: Female, Male Female	57 Participants n=5 Participants	52 Participants n=7 Participants	26 Participants n=5 Participants	66 Participants n=4 Participants	21 Participants n=21 Participants	26 Participants n=10 Participants	248 Participants n=115 Participants
Sex: Female, Male Male	84 Participants n=5 Participants	87 Participants n=7 Participants	44 Participants n=5 Participants	74 Participants n=4 Participants	30 Participants n=21 Participants	24 Participants n=10 Participants	343 Participants n=115 Participants
Region of Enrollment United States	43 participants n=5 Participants	42 participants n=7 Participants	22 participants n=5 Participants	55 participants n=4 Participants	20 participants n=21 Participants	13 participants n=10 Participants	195 participants n=115 Participants
Region of Enrollment Ireland	1 participants n=5 Participants	0 participants n=7 Participants	0 participants n=5 Participants	1 participants n=4 Participants	0 participants n=21 Participants	1 participants n=10 Participants	3 participants n=115 Participants
Region of Enrollment Italy	7 participants n=5 Participants	6 participants n=7 Participants	2 participants n=5 Participants	3 participants n=4 Participants	2 participants n=21 Participants	1 participants n=10 Participants	21 participants n=115 Participants
Region of Enrollment Switzerland	1 participants n=5 Participants	1 participants n=7 Participants	1 participants n=5 Participants	2 participants n=4 Participants	1 participants n=21 Participants	0 participants n=10 Participants	6 participants n=115 Participants
Region of Enrollment United Kingdom	0 participants n=5 Participants	0 participants n=7 Participants	0 participants n=5 Participants	3 participants n=4 Participants	2 participants n=21 Participants	4 participants n=10 Participants	9 participants n=115 Participants
Region of Enrollment India	12 participants n=5 Participants	12 participants n=7 Participants	10 participants n=5 Participants	10 participants n=4 Participants	5 participants n=21 Participants	2 participants n=10 Participants	51 participants n=115 Participants
Region of Enrollment France	7 participants n=5 Participants	12 participants n=7 Participants	6 participants n=5 Participants	6 participants n=4 Participants	1 participants n=21 Participants	5 participants n=10 Participants	37 participants n=115 Participants
Region of Enrollment Czech Republic	0 participants n=5 Participants	1 participants n=7 Participants	0 participants n=5 Participants	0 participants n=4 Participants	0 participants n=21 Participants	0 participants n=10 Participants	1 participants n=115 Participants
Region of Enrollment Mexico	20 participants n=5 Participants	14 participants n=7 Participants	10 participants n=5 Participants	8 participants n=4 Participants	7 participants n=21 Participants	9 participants n=10 Participants	68 participants n=115 Participants
Region of Enrollment Puerto Rico	0 participants n=5 Participants	1 participants n=7 Participants	0 participants n=5 Participants	1 participants n=4 Participants	0 participants n=21 Participants	0 participants n=10 Participants	2 participants n=115 Participants
Region of Enrollment Canada	9 participants n=5 Participants	12 participants n=7 Participants	2 participants n=5 Participants	13 participants n=4 Participants	1 participants n=21 Participants	3 participants n=10 Participants	40 participants n=115 Participants
Region of Enrollment Brazil	10 participants n=5 Participants	5 participants n=7 Participants	5 participants n=5 Participants	11 participants n=4 Participants	4 participants n=21 Participants	6 participants n=10 Participants	41 participants n=115 Participants
Region of Enrollment Poland	2 participants n=5 Participants	2 participants n=7 Participants	0 participants n=5 Participants	1 participants n=4 Participants	1 participants n=21 Participants	0 participants n=10 Participants	6 participants n=115 Participants
Region of Enrollment Belgium	4 participants n=5 Participants	6 participants n=7 Participants	1 participants n=5 Participants	5 participants n=4 Participants	0 participants n=21 Participants	1 participants n=10 Participants	17 participants n=115 Participants
Region of Enrollment Australia	8 participants n=5 Participants	7 participants n=7 Participants	4 participants n=5 Participants	13 participants n=4 Participants	1 participants n=21 Participants	1 participants n=10 Participants	34 participants n=115 Participants
Region of Enrollment South Africa	9 participants n=5 Participants	8 participants n=7 Participants	5 participants n=5 Participants	3 participants n=4 Participants	2 participants n=21 Participants	0 participants n=10 Participants	27 participants n=115 Participants
Region of Enrollment Germany	2 participants n=5 Participants	2 participants n=7 Participants	0 participants n=5 Participants	1 participants n=4 Participants	2 participants n=21 Participants	2 participants n=10 Participants	9 participants n=115 Participants
Region of Enrollment Netherlands	2 participants n=5 Participants	5 participants n=7 Participants	1 participants n=5 Participants	2 participants n=4 Participants	2 participants n=21 Participants	1 participants n=10 Participants	13 participants n=115 Participants
Region of Enrollment Korea, Republic of	4 participants n=5 Participants	3 participants n=7 Participants	1 participants n=5 Participants	2 participants n=4 Participants	0 participants n=21 Participants	1 participants n=10 Participants	11 participants n=115 Participants
Participants with Inadequate Response/Intolerance to Prior Anti-Tumor (TNF) Therapy (Infliximab) Inadequate Response/Intolerant to prior Infliximab	45 participants n=5 Participants	46 participants n=7 Participants	24 participants n=5 Participants	45 participants n=4 Participants	21 participants n=21 Participants	21 participants n=10 Participants	202 participants n=115 Participants
Participants with Inadequate Response/Intolerance to Prior Anti-Tumor (TNF) Therapy (Infliximab) No Inadequate Response/Intolerance to Infliximab	96 participants n=5 Participants	93 participants n=7 Participants	46 participants n=5 Participants	95 participants n=4 Participants	30 participants n=21 Participants	29 participants n=10 Participants	389 participants n=115 Participants

PRIMARY outcome

Timeframe: Week 12 (Day IP-85)

Population: All participants who were randomized and received at least one infusion of study medication (Intent To Treat Population, ITT) were included in the efficacy analyses. Participants with missing Mayo score were defined as not having achieved clinical response, remission, or mucosal healing.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=140 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=137 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=69 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=139 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
Induction Period (IP); Number of Participants With Clinical Response (Per Mayo Score) at Week 12: IP Cohort 1 (IP1C)	30 participants	26 participants	14 participants	41 participants	—	—

PRIMARY outcome

Timeframe: Month 12 (Day MP-365)

Population: All participants in the ITT Population were included in the efficacy analyses. Participants with missing Mayo score were defined as not having achieved clinical response, remission, or mucosal healing.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=64 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=64 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
Maintenance Period (MP); Number of Participants With Clinical Response (Per Mayo Score) at Month 12	11 participants	11 participants	—	—	—	—

PRIMARY outcome

Timeframe: Day OL-1 through the end of the OL

Population: All participants who received at least 1 infusion of open-label study medication at any time were included in the safety analyses of the Open-Label Extension phase.

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

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=349 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
Open-Label Extension Period (OL); Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation AEs	241 participants	—	—	—	—	—
Open-Label Extension Period (OL); Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation Related AEs	100 participants	—	—	—	—	—
Open-Label Extension Period (OL); Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation Deaths	1 participants	—	—	—	—	—
Open-Label Extension Period (OL); Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation SAEs	66 participants	—	—	—	—	—
Open-Label Extension Period (OL); Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation Related SAEs	9 participants	—	—	—	—	—
Open-Label Extension Period (OL); Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation AEs Leading to Discontinuation	7 participants	—	—	—	—	—
Open-Label Extension Period (OL); Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation SAEs Leading to Discontinuation	4 participants	—	—	—	—	—

PRIMARY outcome

Timeframe: Day OL-1 through Day OL-729

Population: All participants who received at least 1 infusion of open-label study medication at any time were included in the safety analyses of the Open-Label Extension phase.

AE=any new untoward medical occurrence or worsening of a pre-existing medical condition which does not necessarily have a causal relationship with this treatment. AEs of special interest are those AEs that may be associated with the use of immunomodulatory drugs, including all infections, serious infections, and opportunistic infections; autoimmune disorders; neoplasms; acute infusional AEs (pre-specified AEs occurring within 1 hour of start of infusion) and peri-infusional AEs (pre-specified AEs occurring within 24 hours of the start of infusion).

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=349 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
OL; Number of Participants With AEs of Special Interest Infections and Infestations	127 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Serious Infections	9 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Opportunistic Infections-Total	2 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Opportunistic Infections-cytomegalovirus	1 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Opportunistic Infections-listeriosis	1 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Malignancies-Total	5 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Malignancies-Basal Cell Carcinoma	2 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Malignancies-Bowen's Disease	1 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Malignancies-Chronic Myeloid Leukemia	1 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Malignancies-Squamous Cell Carcinoma	1 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Autoimmune Disorders-Total	5 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Autoimmune Disorders-episcleritis	2 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Autoimmune Disorders-scleritis	1 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Autoimmune Disorders-anemia hemolytic autoimmune	1 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Autoimmune Disorders-psoriasis	1 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Acute Infusional AEs	12 participants	—	—	—	—	—
OL; Number of Participants With AEs of Special Interest Peri-infusional AEs	25 participants	—	—	—	—	—

PRIMARY outcome

Timeframe: Day OL-1 through Day OL-729

Population: As the results of this study were presented in a synoptic report, physical examination evaluations were not summarized. Laboratory abnormalities and vital signs were collected and summarized.

Complete physical examination was obtained at the Screening Visit, Day MP-365, and OL Final Visit/Early Termination visits. Interim physical examinations were performed at other study visits. Interim physical exam were not as comprehensive as the initial full examination but did note any changes in the participant's condition since the last assessment and did not preclude examination of any of the body systems as clinically indicated. Participants were observed for AEs and vital signs (blood pressure, heart rate, and temperature).

Outcome measures

Outcome data not reported

PRIMARY outcome

Timeframe: Day OL-1 through Day OL-729

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

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

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=349 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
OL; Number of Participants With Marked Hematology Laboratory Abnormalities Low HGB; n=326	20 participants	—	—	—	—	—
OL; Number of Participants With Marked Hematology Laboratory Abnormalities Low hematocrit; n=322	17 participants	—	—	—	—	—
OL; Number of Participants With Marked Hematology Laboratory Abnormalities Low erythrocytes; n=326	6 participants	—	—	—	—	—
OL; Number of Participants With Marked Hematology Laboratory Abnormalities High PLT; n=323	3 participants	—	—	—	—	—
OL; Number of Participants With Marked Hematology Laboratory Abnormalities Low leukocytes; n=326	3 participants	—	—	—	—	—
OL; Number of Participants With Marked Hematology Laboratory Abnormalities High leukocytes; n=326	18 participants	—	—	—	—	—
OL; Number of Participants With Marked Hematology Laboratory Abnormalities Low neutrophils + bands; n=324	1 participants	—	—	—	—	—
OL; Number of Participants With Marked Hematology Laboratory Abnormalities High eosinophils; n=324	17 participants	—	—	—	—	—
OL; Number of Participants With Marked Hematology Laboratory Abnormalities High monocytes; n=324	2 participants	—	—	—	—	—
OL; Number of Participants With Marked Hematology Laboratory Abnormalities Low lymphocytes; n=324	43 participants	—	—	—	—	—

PRIMARY outcome

Timeframe: Day OL-1 through Day OL-729

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

Low=lower than LLN, High=greater than ULN. LLN/ULN= Alkaline phosphatase (ALP): \>2 x ULN; aspartate aminotransferase (AST): \>3 x ULN; alanine aminotransferase (ALT): \>3 x ULN; G-Glutamyl transferase (GGT): \>2 x ULN; Bilirubin: \>2 x ULN; blood urea nitrogen (BUN): \>2 x BL; creatinine: \>4 x BL; potassium (K): \<0.9 x LLN/ \>1.1 x ULN; calcium (Ca): \<0.8 x LLN/\>1.2 x ULN; phosphorous (P): \<0.75 x LLN/ \>1.2 5 x ULN

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=349 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
OL; Number of Participants With Liver and Kidney Function and Electrolyte Laboratory Abnormalities High ALP, n=331	4 participants	—	—	—	—	—
OL; Number of Participants With Liver and Kidney Function and Electrolyte Laboratory Abnormalities High AST, n=331	3 participants	—	—	—	—	—
OL; Number of Participants With Liver and Kidney Function and Electrolyte Laboratory Abnormalities High ALT; n=331	3 participants	—	—	—	—	—
OL; Number of Participants With Liver and Kidney Function and Electrolyte Laboratory Abnormalities High GGT; n=332	17 participants	—	—	—	—	—
OL; Number of Participants With Liver and Kidney Function and Electrolyte Laboratory Abnormalities High bilirubin, n=331	1 participants	—	—	—	—	—
OL; Number of Participants With Liver and Kidney Function and Electrolyte Laboratory Abnormalities High BUN; n=310	10 participants	—	—	—	—	—
OL; Number of Participants With Liver and Kidney Function and Electrolyte Laboratory Abnormalities High creatinine; n=330	5 participants	—	—	—	—	—
OL; Number of Participants With Liver and Kidney Function and Electrolyte Laboratory Abnormalities Low K; n=331	7 participants	—	—	—	—	—
OL; Number of Participants With Liver and Kidney Function and Electrolyte Laboratory Abnormalities Low Ca; n=330	2 participants	—	—	—	—	—
OL; Number of Participants With Liver and Kidney Function and Electrolyte Laboratory Abnormalities Low P; n=330	4 participants	—	—	—	—	—
OL; Number of Participants With Liver and Kidney Function and Electrolyte Laboratory Abnormalities High P, n=330	1 participants	—	—	—	—	—

PRIMARY outcome

Timeframe: Day OL-1 through Day OL-729

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

Low=lower than LLN, High=greater than ULN. LLN/ULN= serum glucose (Glu): \<65 mg/dL/ \>220 mg/dL; fasting serum Glu: \<0.8 x LLN/ \>1.5 x ULN; total protein: \< 0.9 x LLN/ \>1.1 x ULN; albumin:\<0.9 x LLN; uric acid: \>1.5 x ULN. For Urinalysis (Urine protein, urine Glu, urine blood, leukocyte esterase, Red Blood Cells \[RBCs\], White Blood Cells \[WBCs\]): Use ≥2 when BL value missing or value ≥4, or when pre-dose=0 or 0.5. Use ≥3 when pre-dose=1. Use ≥4 when pre-dose=2 or 3

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=349 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
OL; Number of Participants With Chemistry and Urinalysis Laboratory Abnormalities Low Glu; n=245	4 participants	—	—	—	—	—
OL; Number of Participants With Chemistry and Urinalysis Laboratory Abnormalities High Glu; n=245	6 participants	—	—	—	—	—
OL; Number of Participants With Chemistry and Urinalysis Laboratory Abnormalities Low protein; n=331	3 participants	—	—	—	—	—
OL; Number of Participants With Chemistry and Urinalysis Laboratory Abnormalities Low albumin; n=331	12 participants	—	—	—	—	—
OL; Number of Participants With Chemistry and Urinalysis Laboratory Abnormalities High urine protein; n=312	11 participants	—	—	—	—	—
OL; Number of Participants With Chemistry and Urinalysis Laboratory Abnormalities High urine Glu; n=312	4 participants	—	—	—	—	—
OL; Number of Participants With Chemistry and Urinalysis Laboratory Abnormalities High urine blood; n=312	27 participants	—	—	—	—	—
OL; Number of Participants With Chemistry and Urinalysis Laboratory Abnormalities High leukocyte esterase; n=122	10 participants	—	—	—	—	—
OL; Number of Participants With Chemistry and Urinalysis Laboratory Abnormalities High urine RBC; n=115	22 participants	—	—	—	—	—
OL; Number of Participants With Chemistry and Urinalysis Laboratory Abnormalities High urine WBC; n=150	45 participants	—	—	—	—	—

SECONDARY outcome

Timeframe: Baseline

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=141 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=139 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=70 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=140 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Baseline Mayo Score: IP1C	8.9 units on a scale Standard Deviation 1.74	8.8 units on a scale Standard Deviation 1.73	8.6 units on a scale Standard Deviation 1.82	8.8 units on a scale Standard Deviation 1.59	—	—

SECONDARY outcome

Timeframe: Week 12 (Day IP-85)

The Mayo Scoring system ranges from 0 - 12 points and is a composite index consisting of 4 disease variables (stool frequency, rectal bleeding, endoscopy evaluation, and Physician's Global Assessment). Higher Mayo scores indicate greater severity of disease. Clinical remission is defined as a Mayo score of ≤ 2 points with no individual subscore exceeding 1 point.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=140 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=137 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=69 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=139 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants in Clinical Remission (Per Mayo Score) at Week 12: IP1C	3 participants	6 participants	4 participants	15 participants	—	—

SECONDARY outcome

Timeframe: Week 12 (Day IP-85)

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=140 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=137 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=69 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=139 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants in Mucosal Healing (Per Mayo Score) at Week 12: IP1C	24 participants	20 participants	11 participants	36 participants	—	—

SECONDARY outcome

Timeframe: Week 12 (Day IP-85)

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=139 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=69 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=137 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=140 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants With Clinical Response (Per Mayo Score) at Week 12 Analyzed by Cochran-Armitage Trend Test for Dose-Response Relationship: IP1C	41 participants	14 participants	26 participants	30 participants	—	—

SECONDARY outcome

Timeframe: Baseline

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

The Inflammatory Bowel Disease Questionnaire (IBDQ) was used to measure disease specific quality of life. The IBDQ consists of a self-administered 32-item questionnaire that evaluates quality of life across 4 dimensional scores: Bowel, Systemic, Social and Emotional. The response to each question can range from 1 to 7, with 1 indicating severe problem and 7 indicating normal health. The total IBDQ is computed as the sum of the responses to the individual IBDQ questions. The total score can range between 32 to 224 with higher scores indicating a better quality of life.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=141 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=139 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=70 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=140 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Baseline Inflammatory Bowel Disease Questionnaire (IBDQ) Score: IP1C	120.0 units on a scale Standard Deviation 35.43	121.5 units on a scale Standard Deviation 36.42	126.9 units on a scale Standard Deviation 35.93	124.3 units on a scale Standard Deviation 33.43	—	—

SECONDARY outcome

Timeframe: Baseline (Day IP-1), Day IP-85 (Week 12)

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=97 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=99 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=46 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=112 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Mean Change From Baseline To Week 12 in Inflammatory Bowel Disease Questionnaire (IBDQ): IP1C	9.45 units on a scale Standard Error 3.514	13.36 units on a scale Standard Error 3.476	9.87 units on a scale Standard Error 5.108	23.68 units on a scale Standard Error 3.268	—	—

SECONDARY outcome

Timeframe: Day IP-85 (Week 12)

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=104 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=106 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=53 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=118 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants With Mayo Rectal Bleeding Subscores Indicating Mild Disease (≤1 Point) at Week 12: IP1C Rectal Subscore=0	28 participants	36 participants	16 participants	47 participants	—	—
IP; Number of Participants With Mayo Rectal Bleeding Subscores Indicating Mild Disease (≤1 Point) at Week 12: IP1C Rectal Subscore=1	31 participants	30 participants	13 participants	27 participants	—	—

SECONDARY outcome

Timeframe: Day IP-85 (Week 12)

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=104 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=106 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=53 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=118 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants With Mayo Stool Frequency Subscores Indicating Mild Disease (≤1 Point) at Week 12: IP1C Stool Frequency Subscore=0	13 participants	8 participants	4 participants	14 participants	—	—
IP; Number of Participants With Mayo Stool Frequency Subscores Indicating Mild Disease (≤1 Point) at Week 12: IP1C Stool Frequency Subscore=1	14 participants	21 participants	10 participants	32 participants	—	—

SECONDARY outcome

Timeframe: Day IP-85 (Week 12)

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=104 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=106 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=53 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=118 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants With Mayo Physician Global Assessment (PGA) Subscores Indicating Mild Disease (≤1 Point) at Week 12: IP1C PGA Subscore=0	2 participants	4 participants	3 participants	11 participants	—	—
IP; Number of Participants With Mayo Physician Global Assessment (PGA) Subscores Indicating Mild Disease (≤1 Point) at Week 12: IP1C PGA Subscore=1	22 participants	25 participants	15 participants	34 participants	—	—

SECONDARY outcome

Timeframe: Week 12 (Day IP-85)

Population: All participants in ITT Population were included in the efficacy analyses. Participants with missing Mayo score were defined as not having achieved clinical response, remission, or mucosal healing. Prior inadequate response/intolerance was to an approved anti-TNF agent at an approved labeled dose for ≥8 weeks.

The Mayo Scoring system (range 0-12 points, high scores=greater severity of disease) is a composite index consisting of 4 disease variables (stool frequency, rectal bleeding, endoscopy evaluation, and Physician's Global Assessment). Clinical response=reduction from baseline in the Mayo score of ≥ 3 points and ≥ 30%, with accompanying decrease in the rectal bleeding subscore of ≥ 1 point or absolute rectal bleeding subscore of ≤ 1 point. Inadequate response/intolerance=inadequate response/intolerance to an approved anti-TNF agent prior to this study at an approved labeled dose for ≥8 weeks.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=45 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=24 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=46 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=45 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants Who Are Anti-TNF-Inadequate Responders/Anti-TNF Intolerant With Clinical Response At Week 12 Analyzed by Cochran-Armitage Trend Test for Dose-Response Relationship: IP1C	12 participants	4 participants	7 participants	8 participants	—	—

SECONDARY outcome

Timeframe: Week 12 (Day IP-85)

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=45 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=46 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=24 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=45 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants With Clinical Response At Week 12 Among Participants With Anti-TNF (Infliximab) Failure/Intolerance: IP1C	8 participants	7 participants	4 participants	12 participants	—	—

SECONDARY outcome

Timeframe: Week 12 (Day IP-85)

The Mayo Scoring system (range 0-12 points, high scores=greater severity of disease) is a composite index consisting of 4 disease variables (stool frequency, rectal bleeding, endoscopy evaluation, and Physician's Global Assessment). Clinical remission is defined as a Mayo score of ≤ 2 points with no individual subscore exceeding 1 point. Inadequate response/intolerance =inadequate response/intolerance to an approved anti-TNF agent prior to this study at an approved labeled dose for ≥8 weeks.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=45 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=46 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=24 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=45 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants in Clinical Remission at Week 12 Among Participants With Anti-TNF (Infliximab) Failure/Intolerance: IP1C	2 participants	0 participants	0 participants	4 participants	—	—

SECONDARY outcome

Timeframe: Week 12 (Day IP-85)

The Mayo Scoring system ranges from 0 - 12 points and is a composite index consisting of 4 disease variables (stool frequency, rectal bleeding, endoscopy evaluation, and Physician's Global Assessment). Higher Mayo scores indicate greater severity of disease. Mucosal healing was defined as endoscopic subscore ≤ 1 point. Inadequate response/intolerance = inadequate response/intolerance to an approved anti-TNF agent prior to this study at an approved labeled dose for ≥8 weeks.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=45 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=46 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=24 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=45 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants in Mucosal Healing at Week 12 Among Participants With Anti-TNF (Infliximab) Failure/Intolerance: IP1C	4 participants	4 participants	1 participants	13 participants	—	—

SECONDARY outcome

Timeframe: Day IP-1 through Day IP-85

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=141 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=139 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=70 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=140 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg n=51 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg n=50 Participants During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation: IP1C + IP2C AEs	85 participants	92 participants	39 participants	86 participants	26 participants	27 participants
IP; Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation: IP1C + IP2C Related AEs	48 participants	46 participants	23 participants	37 participants	10 participants	11 participants
IP; Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation: IP1C + IP2C Deaths	1 participants	0 participants	0 participants	0 participants	0 participants	0 participants
IP; Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation: IP1C + IP2C SAEs	22 participants	20 participants	8 participants	7 participants	6 participants	4 participants
IP; Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation: IP1C + IP2C Related SAEs	4 participants	1 participants	1 participants	3 participants	1 participants	0 participants
IP; Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation: IP1C + IP2C AEs Leading to Discontinuation	4 participants	6 participants	2 participants	5 participants	1 participants	0 participants
IP; Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation: IP1C + IP2C SAEs Leading to Discontinuation	1 participants	2 participants	1 participants	3 participants	1 participants	0 participants

SECONDARY outcome

Timeframe: Day IP-1 through Day IP-85

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=141 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=139 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=70 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=140 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg n=51 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg n=50 Participants During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Serious Infections	5 participants	0 participants	1 participants	0 participants	0 participants	0 participants
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Infections and Infestations	23 participants	29 participants	8 participants	25 participants	12 participants	7 participants
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Opportunistic Infections-Total	0 participants	1 participants	1 participants	0 participants	0 participants	0 participants
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Opportunistic Infections-candidiasis	0 participants	0 participants	1 participants	0 participants	0 participants	0 participants
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Opportunistic Infections-esophageal candidiasis	0 participants	1 participants	0 participants	0 participants	0 participants	0 participants
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Malignancies-Total	1 participants	0 participants	0 participants	1 participants	0 participants	0 participants
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Malignancies-basal cell carcinoma	1 participants	0 participants	0 participants	0 participants	0 participants	0 participants
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Malignancies-malignant melanoma	0 participants	0 participants	0 participants	1 participants	0 participants	0 participants
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Autoimmune Disorders-Total	2 participants	1 participants	0 participants	4 participants	0 participants	0 participants
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Autoimmune Disorders-uveitis	1 participants	1 participants	0 participants	1 participants	0 participants	0 participants
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Autoimmune Disorders-episcleritis	0 participants	0 participants	0 participants	1 participants	0 participants	0 participants
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Autoimmune Disorders-scleritis	0 participants	0 participants	0 participants	1 participants	0 participants	0 participants
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Autoimmune Disorders-rheumatoid arthritis	0 participants	0 participants	0 participants	1 participants	0 participants	0 participants
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Autoimmune Disorders-psoriasis	1 participants	0 participants	0 participants	0 participants	0 participants	0 participants
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Acute Infusional AEs	4 participants	4 participants	0 participants	2 participants	0 participants	0 participants
IP; Number of Participants With AEs Of Special Interest: IP1C + IP2C Peri Infusional AEs	17 participants	20 participants	5 participants	14 participants	2 participants	4 participants

SECONDARY outcome

Timeframe: Day IP-1 through Day IP-85

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Day IP-1 through Day IP-85

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=141 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=139 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=70 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=140 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants With Marked Hematology Laboratory Abnormalities: IP1C Low HGB; n=136, n=134, n=67, n=133	3 participants	2 participants	6 participants	1 participants	—	—
IP; Number of Participants With Marked Hematology Laboratory Abnormalities: IP1C Low hematocrit; n=134, n=133, n=67, n=131	1 participants	2 participants	4 participants	1 participants	—	—
IP; Number of Participants With Marked Hematology Laboratory Abnormalities: IP1C Low erythrocytes; n=136, n=134, n=67, n=133	2 participants	2 participants	4 participants	1 participants	—	—
IP; Number of Participants With Marked Hematology Laboratory Abnormalities: IP1C Low PLT; n=136, n=133, n=66, n=133	1 participants	0 participants	1 participants	0 participants	—	—
IP; Number of Participants With Marked Hematology Laboratory Abnormalities: IP1C High PLT; n=136, n=133, n=66, n=133	0 participants	2 participants	0 participants	0 participants	—	—
IP; Number of Participants With Marked Hematology Laboratory Abnormalities: IP1C Low leukocytes; n=136, n=134, n=67, n=133	1 participants	0 participants	4 participants	1 participants	—	—
IP; Number of Participants With Marked Hematology Laboratory Abnormalities: IP1C High leukocytes; n=136, n=134, n=67, n=133	10 participants	6 participants	3 participants	5 participants	—	—
IP; Number of Participants With Marked Hematology Laboratory Abnormalities: IP1C Low neutrophils + bands; n=136, n=134, n=67, n=131	0 participants	0 participants	1 participants	0 participants	—	—
IP; Number of Participants With Marked Hematology Laboratory Abnormalities: IP1C High eosinophils; n=136, n=134, n=67, n=131	6 participants	4 participants	3 participants	4 participants	—	—
IP; Number of Participants With Marked Hematology Laboratory Abnormalities: IP1C High monocytes; n=136, n=134, n=67, n=131	0 participants	0 participants	1 participants	0 participants	—	—
IP; Number of Participants With Marked Hematology Laboratory Abnormalities: IP1C Low lymphocytes; n=136, n=134, n=67, n=131	23 participants	13 participants	11 participants	26 participants	—	—

SECONDARY outcome

Timeframe: Day IP-1 through Day IP-85

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

Low=lower than LLN, High=greater than ULN. LLN/ULN= Alkaline phosphatase (ALP): \>2 x ULN; aspartate aminotransferase (AST): \>3 x ULN; alanine aminotransferase (ALT): \>3 x ULN; G-Glutamyl transferase (GGT): \>2 x ULN; Bilirubin: \>2 x ULN; blood urea nitrogen (BUN): \>2 x BL; creatinine: \>4 x BL; Sodium (Na): \<0.95 x LLN/ \>1.05 x ULN; potassium (K): \<0.9 x LLN/ \>1.1 x ULN; calcium (Ca): \<0.8 x LLN/\>1.2 x ULN; phosphorous (P): \<0.75 x LLN/ \>1.2 5 x ULN

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=141 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=139 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=70 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=140 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants With Marked Liver and Kidney Function and Electrolyte Laboratory Abnormalities: IP1C High ALP, n=137, n=135, n=66, n=135	1 participants	0 participants	0 participants	0 participants	—	—
IP; Number of Participants With Marked Liver and Kidney Function and Electrolyte Laboratory Abnormalities: IP1C High ALT; n=137, n=135, n=66, n=135	0 participants	1 participants	0 participants	0 participants	—	—
IP; Number of Participants With Marked Liver and Kidney Function and Electrolyte Laboratory Abnormalities: IP1C High GGT; n=137, n=135, n=66, n=135	6 participants	2 participants	0 participants	2 participants	—	—
IP; Number of Participants With Marked Liver and Kidney Function and Electrolyte Laboratory Abnormalities: IP1C High BUN; n=127, n=130, n=62, n=124	0 participants	2 participants	2 participants	3 participants	—	—
IP; Number of Participants With Marked Liver and Kidney Function and Electrolyte Laboratory Abnormalities: IP1C High creatinine; n=137, n=135, n=66, n=135	0 participants	0 participants	0 participants	1 participants	—	—
IP; Number of Participants With Marked Liver and Kidney Function and Electrolyte Laboratory Abnormalities: IP1C Low Na; n=138, n=135, n=66, n=135	0 participants	0 participants	2 participants	0 participants	—	—
IP; Number of Participants With Marked Liver and Kidney Function and Electrolyte Laboratory Abnormalities: IP1C Low K; n=138, n=135, n=66, n=135	1 participants	2 participants	2 participants	0 participants	—	—
IP; Number of Participants With Marked Liver and Kidney Function and Electrolyte Laboratory Abnormalities: IP1C High K; n=138, n=135, n=66, n=135	0 participants	1 participants	0 participants	1 participants	—	—
IP; Number of Participants With Marked Liver and Kidney Function and Electrolyte Laboratory Abnormalities: IP1C Low Ca; n=137, n=135, n=66, n=135	0 participants	1 participants	2 participants	0 participants	—	—
IP; Number of Participants With Marked Liver and Kidney Function and Electrolyte Laboratory Abnormalities: IP1C Low P; n=137, 135, n=66, n=135	0 participants	1 participants	0 participants	3 participants	—	—

SECONDARY outcome

Timeframe: Day IP-1 through Day IP-85

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

Low=lower than LLN, High=greater than ULN. LLN/ULN= serum glucose (Glu): \<65 mg/dL/ \>220 mg/dL; total protein: \< 0.9 x LLN/ \>1.1 x ULN; albumin:\<0.9 x LLN; uric acid: \>1.5 x ULN. For Urinalysis (Urine protein, urine Glu, urine blood, leukocyte esterase, Red Blood Cells \[RBCs\], White Blood Cells \[WBCs\]): Use ≥2 when BL value missing or value ≥4, or when pre-dose=0 or 0.5. Use ≥3 when pre-dose=1. Use ≥4 when pre-dose=2 or 3

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=141 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=139 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=70 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo n=140 Participants During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP1C High leukocyte esterase; n=54, n=51, n=27, n=52	1 participants	5 participants	2 participants	2 participants	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP1C Low Glu; n=88, n=91, n=41, n=105	1 participants	6 participants	2 participants	0 participants	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP1C High Glu; n=88, n=91, n=41, n=105	0 participants	0 participants	1 participants	0 participants	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP1C Low protein; n=137, n=135, n=66, n=135	5 participants	3 participants	3 participants	0 participants	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP1C High protein; n=137, n=135, n=66, n=135	0 participants	1 participants	0 participants	0 participants	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP1C Low albumin; n=137, n=135, n=66, n=135	7 participants	5 participants	3 participants	0 participants	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP1C High urine protein; n=132, n=129, n=66, n=128	5 participants	3 participants	2 participants	4 participants	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP1C High urine Glu; n=132, n=129, n=66, n=128	4 participants	1 participants	2 participants	4 participants	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP1C High urine blood; n=132, n=129, n=66, n=128	6 participants	7 participants	4 participants	11 participants	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP1C High urine RBC; n=47, n=42, n=17, n=52	9 participants	8 participants	4 participants	12 participants	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP1C High urine WBC; n=64, n=56, n=27, n=58	14 participants	21 participants	3 participants	14 participants	—	—

SECONDARY outcome

Timeframe: Day IP-1 through Day IP-85

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

High=greater than Upper Normal Limit (ULN), Low=lower than Lower Normal Limit (LLN). LLN/ULN= Hemoglobin (HGB): \>3 g/dL decrease from Baseline (BL); Hematocrit: \<0.75 x BL; Erythrocytes: \<0.75 x BL; Platelets (PLT): \<0.67 x LLN/\>1.5 x ULN; Leukocytes: \<0.75 x LLN/ \>1.25 x ULN; eosinophils: \>0.750 x 10\^3 c/uL; monocytes: \>2000 mm3; lymphocytes: \<0.750 x 10\^3 c/uL/ \>7.50 x 10\^3 c/uL; blood urea nitrogen (BUN): \>2 x BL; creatinine: \>4 x BL; Sodium (Na): \<0.95 x LLN/ \>1.05 x ULN; potassium (K): \<0.9 x LLN/ \>1.1 x ULN; phosphorous (P): \<0.75 x LLN/ \>1.2 5 x ULN;

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=51 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=50 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C Low Na; n=50, n=50	1 participants	0 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C Low K; n=50, n=50	2 participants	1 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C Low P; n=50, n=50	1 participants	0 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C Low Glu; n=37, n=28	0 participants	2 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C High Glu; n=37, n=28	0 participants	2 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C Low protein; n=50, n=50	2 participants	0 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C Low albumin; n=50, n=50	2 participants	0 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C High urine protein; n=50, n=48	0 participants	4 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C Low HGB; n=50, n=49	2 participants	2 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C Low hematocrit; n=50, n=49	1 participants	0 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C Low erythrocytes; n=50, n=49	1 participants	0 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C High PLT; n=50, n=49	0 participants	1 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C Low leukocytes; n=50, n=49	0 participants	1 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C High leukocytes; n=50, n=49	3 participants	4 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C High eosinophils; n=49, n=49	3 participants	1 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C High monocytes; n=49, n=49	0 participants	1 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C Low lymphocytes; n=49, n=49	5 participants	3 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C High BUN; n=46, n=44	3 participants	1 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C High creatinine; n=50, n=50	1 participants	0 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C High urine Glu; n=50, n=48	0 participants	2 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C High urine blood; n=50, n=48	2 participants	3 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C High leukocyte esterase; n=21, n=16	4 participants	2 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C High urine RBC; n=15, n=20	0 participants	4 participants	—	—	—	—
IP; Number of Participants With Marked Hematology, Liver and Kidney Function, and Electrolyte Laboratory Abnormalities: IP2C High urine WBC; n=24, n=23	7 participants	6 participants	—	—	—	—

SECONDARY outcome

Timeframe: Day IP-1 through Day IP-85

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

Low=lower than LLN, High=greater than ULN. LLN/ULN= serum glucose (Glu): \<65 mg/dL/ \>220 mg/dL; total protein: \< 0.9 x LLN/ \>1.1 x ULN; albumin:\<0.9 x LLN. For Urinalysis (Urine protein, urine Glu, urine blood, leukocyte esterase, Red Blood Cells \[RBCs\], White Blood Cells \[WBCs\]): Use ≥2 when BL value missing or value ≥4, or when pre-dose=0 or 0.5. Use ≥3 when pre-dose=1. Use ≥4 when pre-dose=2 or 3

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=51 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=50 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP2C Low Glu; n=37, n=28	0 participants	2 participants	—	—	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP2C High Glu; n=37, n=28	0 participants	2 participants	—	—	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP2C Low protein; n=50, n=50	2 participants	0 participants	—	—	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP2C Low albumin; n=50, n=50	2 participants	0 participants	—	—	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP2C High urine protein; n=50, n=48	0 participants	4 participants	—	—	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP2C High urine Glu; n=50, n=48	0 participants	2 participants	—	—	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP2C High urine blood; n=50, n=48	2 participants	3 participants	—	—	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP2C High leukocyte esterase; n=21, n=16	4 participants	2 participants	—	—	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP2C High urine RBC; n=15, n=20	0 participants	4 participants	—	—	—	—
IP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities: IP2C High urine WBC; n=24, n=23	7 participants	6 participants	—	—	—	—

SECONDARY outcome

Timeframe: For participants treated in MP: Day IP-1 (Baseline) to Day MP-1 (Day IP-85). For participants treated in OL directly after IP: Day IP-1 to Day OL-1. For participants treated only in IP: All measurements after Day IP-1 (including follow-up visits)

Population: All subjects with at least one post-baseline immunogenicity measurement during the study period were included in the immunogenicity data set. "Positive" was defined as "positive post-baseline IP-1" and with a titer value greater than the baseline titer value. Participants with missing baseline titer were assumed "negative" at baseline.

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

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=189 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=185 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg n=66 Participants During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
IP; Number of Participants With Abatacept-Induced Antibodies: IP1C + IP2C Total	6 participants	19 participants	4 participants	—	—	—
IP; Number of Participants With Abatacept-Induced Antibodies: IP1C + IP2C CTLA4/Possibly Ig	2 participants	17 participants	4 participants	—	—	—
IP; Number of Participants With Abatacept-Induced Antibodies: IP1C + IP2C Ig and/or Ig Junction	4 participants	3 participants	0 participants	—	—	—

SECONDARY outcome

Timeframe: Month 12 (Day MP-365)

The Mayo Scoring system ranges from 0 - 12 points and is a composite index consisting of 4 disease variables (stool frequency, rectal bleeding, endoscopy evaluation, and Physician's Global Assessment). Higher Mayo scores indicate greater severity of disease. Clinical remission is defined as a Mayo score of ≤ 2 points with no individual subscore exceeding 1 point.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=64 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=64 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
MP; Number of Participants in Clinical Remission at Month 12	8 participants	9 participants	—	—	—	—

SECONDARY outcome

Timeframe: Month 12 (Day MP-365)

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=17 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=12 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
MP; Number of Participants With Mayo Endoscopic Subscores Indicating Mucosal Healing (≤1 Point) at Month 12	11 participants	10 participants	—	—	—	—

SECONDARY outcome

Timeframe: Month 6 (Day MP-169), Month 12 (Day MP-365)

Population: Due to the early termination of the study after preliminary IP1C results were reviewed and the primary efficacy endpoint was not achieved, the secondary endpoint analysis to determine the percentage of participants in clinical remission at both Month 6 and Month 12 was not conducted for the MP as planned.

The Mayo Scoring system ranges from 0 - 12 points and is a composite index consisting of 4 disease variables (stool frequency, rectal bleeding, endoscopy evaluation, and Physician's Global Assessment). Higher Mayo scores indicate greater severity of disease. Clinical remission is defined as a Mayo score of ≤ 2 points with no individual subscore exceeding 1 point.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Day MP-365 (Month 12)

Population: Due to the early termination of the study after preliminary IP1C results were reviewed and the primary efficacy endpoint was not achieved, the secondary endpoint analyses for corticosteroid sparing were not conducted for the MP as planned.

Baseline corticosteroids equivalent of ≤30 mg prednisone daily. The Mayo Scoring system ranges from 0 - 12 points and is a composite index consisting of 4 disease variables (stool frequency, rectal bleeding, endoscopy evaluation, and Physician's Global Assessment). Higher Mayo scores indicate greater frequency or severity. Clinical remission is defined as a Mayo score of ≤ 2 points with no individual subscore exceeding 1 point.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Day MP-365

Population: Due to the early termination of the study after preliminary IP1C results were reviewed and the primary efficacy endpoint was not achieved, the secondary endpoint analysis for changes from baseline in IBDQ responses were not conducted for the MP as planned.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Day MP-365

Population: Due to the early termination of the study after preliminary IP1C results were reviewed and the primary efficacy endpoint was not achieved, the secondary endpoint analysis for changes from baseline in SF-36 responses were not conducted for the MP as planned.

The SF-36 is a validated instrument to measure health-related quality of life across multiple disease states. Individual subscale scores and 2 summary scores are calculated: (1) physical component summary (PCS) which includes physical functioning, role-physical, bodily pain, and general health; (2) mental component summary (MCS) which includes vitality, social functioning, role-emotional, and mental health. Each scale is directly transformed into a 0-100 scale on the assumption that each question carries equal weight, with values ranging from worse health (0) to best health (100).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Day MP-365 (Month 12)

Population: Due to the early termination of the study after preliminary IP1C results were reviewed and the primary efficacy endpoint was not achieved, the secondary endpoint analyses for corticosteroid sparing were not conducted for the MP as planned.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Day MP-365 (Month 12)

Population: Due to the early termination of the study after preliminary IP1C results were reviewed and the primary efficacy endpoint was not achieved, the secondary endpoint analysis to determine the percentage of participants with rectal subscores indicating mild disease (≤1) was not conducted for the MP as planned.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Day MP-365 (Month 12)

Population: Due to the early termination of the study after preliminary IP1C results were reviewed and the primary efficacy endpoint was not achieved, the secondary endpoint analysis to determine the percentage of participants with stool frequency subscores indicating mild disease (≤1) was not conducted for the MP as planned.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Day MP-365 (Month 12)

Population: Due to the early termination of the study after preliminary IP1C results were reviewed and the primary efficacy endpoint was not achieved, the secondary endpoint analysis to determine the percentage of participants with PGA subscores indicating mild disease (≤1) was not conducted for the MP as planned.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Month 12 (Day MP-365)

Population: Due to the early termination of the study after preliminary IP1C results were reviewed and the primary efficacy endpoint was not achieved, the secondary subgroup analyses of clinical response in subjects who have had an inadequate response and/or intolerance to anti-TNF therapy was not conducted for the MP as planned.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Month 12 (Day MP-365)

Population: Due to the early termination of the study after preliminary IP1C results were reviewed and the primary efficacy endpoint was not achieved, the secondary subgroup analyses of clinical remission in subjects who have had an inadequate response and/or intolerance to anti-TNF therapy was not conducted for the MP as planned.

The Mayo Scoring system (range 0-12 points, high scores=greater severity of disease) is a composite index consisting of 4 disease variables (stool frequency, rectal bleeding, endoscopy evaluation, and Physician's Global Assessment). Clinical remission is defined as a Mayo score of ≤ 2 points with no individual subscore exceeding 1 point. Inadequate response/intolerance =inadequate response/intolerance to an approved anti-TNF agent prior to this study at an approved labeled dose for ≥8 weeks.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Month 12 (Day MP-365)

Population: Due to the early termination of the study after preliminary IP1C results were reviewed and the primary efficacy endpoint was not achieved, the secondary subgroup analyses of mucosal healing in subjects who have had an inadequate response and/or intolerance to anti-TNF therapy was not conducted for the MP as planned.

The Mayo Scoring system ranges from 0 - 12 points and is a composite index consisting of 4 disease variables (stool frequency, rectal bleeding, endoscopy evaluation, and Physician's Global Assessment). Higher Mayo scores indicate greater severity of disease. Mucosal healing was defined as endoscopic subscore ≤1 point. Inadequate response/intolerance = inadequate response/intolerance to an approved anti-TNF agent prior to this study at an approved labeled dose for ≥8 weeks.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: For participants not entering OL: All measurements starting after Day MP-1 (including follow-up visits). For participants entering OL: From first measurement after Day MP-1 to Day MP-365 (Day OL-1).

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=62 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=47 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
MP; Number of Participants With Abatacept-Induced Antibodies Total	8 participants	20 participants	—	—	—	—
MP; Number of Participants With Abatacept-Induced Antibodies CTLA4/Possibly Ig	8 participants	17 participants	—	—	—	—
MP; Number of Participants With Abatacept-Induced Antibodies Ig and/or Ig Junction	0 participants	3 participants	—	—	—	—

SECONDARY outcome

Timeframe: Day MP-1 through Day MP-365

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=65 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=66 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
MP; Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation AEs	39 participants	36 participants	—	—	—	—
MP; Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation Related AEs	12 participants	13 participants	—	—	—	—
MP; Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation Deaths	1 participants	0 participants	—	—	—	—
MP; Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation SAEs	7 participants	4 participants	—	—	—	—
MP; Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation Related SAEs	2 participants	2 participants	—	—	—	—
MP; Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation AEs Leading to Discontinuation	1 participants	3 participants	—	—	—	—
MP; Number of Participants With Adverse Events (AEs), Related AEs, Deaths, Serious AEs (SAEs), Related SAEs, and AEs Leading to Discontinuation SAEs Leading to Discontinuation	1 participants	1 participants	—	—	—	—

SECONDARY outcome

Timeframe: Day MP-1 through Day MP-365

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=65 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=66 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
MP; Number of Participants With AEs of Special Interest Infections and Infestations	39 participants	36 participants	—	—	—	—
MP; Number of Participants With AEs of Special Interest Serious Infections	5 participants	2 participants	—	—	—	—
MP; Number of Participants With AEs of Special Interest Opportunistic Infections-Total	1 participants	0 participants	—	—	—	—
MP; Number of Participants With AEs of Special Interest Opportunistic Infections-pneumonia herpes viral	1 participants	0 participants	—	—	—	—
MP; Number of Participants With AEs of Special Interest Malignancies-Total	0 participants	1 participants	—	—	—	—
MP; Number of Participants With AEs of Special Interest Malignancies-breast cancer	0 participants	1 participants	—	—	—	—
MP; Number of Participants With AEs of Special Interest Autoimmune Disorders-Total	2 participants	0 participants	—	—	—	—
MP; Number of Participants With AEs of Special Interest Autoimmune Disorders-erythema nodosum	1 participants	0 participants	—	—	—	—
MP; Number of Participants With AEs of Special Interest Autoimmune Disorders-pemphigoid	1 participants	0 participants	—	—	—	—
MP; Number of Participants With AEs of Special Interest Acute Infusional AEs	2 participants	1 participants	—	—	—	—
MP; Number of Participants With AEs of Special Interest Peri-infusional AEs	3 participants	2 participants	—	—	—	—

SECONDARY outcome

Timeframe: Day IP-85 through Day MP-365

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Day IP-85 through Day MP-365

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

High=greater than ULN, Low=lower than LLN. LLN/ULN= HGB: \>3 g/dL decrease from Baseline (BL); Hematocrit: \<0.75 x BL; Erythrocytes: \<0.75 x BL; PLT: \<0.67 x LLN/\>1.5 x ULN; Leukocytes: \<0.75 x LLN/ \>1.25 x ULN; neutrophils+bands: \<1.0 x 10\^3 c/uL; eosinophils: \>0.750 x 10\^3 c/uL; monocytes: \>2000 mm3; lymphocytes: \<0.750 x 10\^3 c/uL/ \>7.50 x 10\^3 c/uL; GGT: \>2 x ULN; Bilirubin: \>2 x ULN; BUN: \>2 x BL; Na: \<0.95 x LLN/ \>1.05 x ULN; K: \<0.9 x LLN/ \>1.1 x ULN; Ca: \<0.8 x LLN/\>1.2 x ULN

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=65 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=66 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
MP; Number of Participants With Marked Hematology Laboratory Abnormalities Low HGB; n=64, n=61	1 participants	2 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities Low hematocrit; n=64, n=60	3 participants	2 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities Low erythrocytes; n=64, n=61	1 participants	2 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities High PLT; n= 64, n=61	0 participants	1 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities Low leukocytes; n=64, n=60	2 participants	0 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities High leukocytes; n=64, n=60	2 participants	0 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities Low neutrophils + bands; n=64, n=60	1 participants	0 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities High eosinophils; n=64, n=60	2 participants	3 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities High monocytes; n=64, n=60	1 participants	0 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities Low lymphocytes; n=64, n=60	7 participants	6 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities High lymphocytes; n=64, n=60	1 participants	0 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities High GGT; n=64, n=62	3 participants	2 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities High bilirubin, n=64, n=61	1 participants	0 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities High BUN; n=57, n=59	4 participants	3 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities Low Na; n=64, n=62	0 participants	1 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities Low K; n=64, n=62	1 participants	1 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities Low Ca; n=64, n=61	1 participants	0 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities Low Glu; n=45, n=38	0 participants	2 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities High Glu; n=45, n=38	3 participants	3 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities Low protein; n=64, n=61	0 participants	1 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities High urine protein; n=58, n=58	4 participants	1 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities High urine Glu; n=58, n=58	2 participants	1 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities High urine blood; n=58, n=58	3 participants	7 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities High leukocyte esterase; n=23, n=18	2 participants	5 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities High urine RBC; n=24, n=17	4 participants	4 participants	—	—	—	—
MP; Number of Participants With Marked Hematology Laboratory Abnormalities High urine WBC; n=29, n=21	8 participants	10 participants	—	—	—	—

SECONDARY outcome

Timeframe: Day IP-85 through Day MP-365

Population: The As Treated analysis population was used for all safety summaries and was defined to include all participants who received at least one infusion of study medication.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=65 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=66 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
MP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities Low Glu; n=45, n=38	0 participants	2 participants	—	—	—	—
MP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities High Glu; n=45, n=38	3 participants	3 participants	—	—	—	—
MP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities Low protein; n=64, n=61	0 participants	1 participants	—	—	—	—
MP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities High urine protein; n=58, n=58	4 participants	1 participants	—	—	—	—
MP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities High urine Glu; n=58, n=58	2 participants	1 participants	—	—	—	—
MP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities High urine blood; n=58, n=58	3 participants	7 participants	—	—	—	—
MP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities High leukocyte esterase; n=23, n=18	2 participants	5 participants	—	—	—	—
MP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities High urine RBC; n=24, n=17	4 participants	4 participants	—	—	—	—
MP; Number of Participants With Marked Chemistry and Urinalysis Laboratory Abnormalities High urine WBC; n=29, n=21	8 participants	10 participants	—	—	—	—

SECONDARY outcome

Timeframe: Day OL-1 through Day OL-729

Population: All participants who received at least 1 infusion of open-label study medication at any time were included in the efficacy analyses of the OL. Number of Participants Analyzed=all participants in OL; n=number of evaluable participants.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=347 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
OL; Number of Participants With Clinical Response Over Time Day OL-365 (n=163)	44 participants	—	—	—	—	—
OL; Number of Participants With Clinical Response Over Time Day OL-729 (n=4)	0 participants	—	—	—	—	—

SECONDARY outcome

Timeframe: Day OL-1 through Day OL-729

The Mayo Scoring system ranges from 0 - 12 points and is a composite index consisting of 4 disease variables (stool frequency, rectal bleeding, endoscopy evaluation, and Physician's Global Assessment). Higher Mayo scores indicate greater severity of disease. Clinical remission is defined as a Mayo score of ≤ 2 points with no individual subscore exceeding 1 point.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=347 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
OL; Number of Participants With Clinical Remission Over Time Day OL-365 (n=163)	18 participants	—	—	—	—	—
OL; Number of Participants With Clinical Remission Over Time Day OL-729 (n=4)	0 participants	—	—	—	—	—

SECONDARY outcome

Timeframe: Open-Label Period (Day OL-1 through Day OL-729)

Population: Due to the early termination of the study after preliminary IP1C results were reviewed and the primary efficacy endpoint was not achieved, the secondary subgroup analyses of mucosal healing was not conducted for the OL as planned.

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=17 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg n=12 Participants During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
OL; Number of Participants With Mayo Endoscopic Subscores Indicating Mucosal Healing (≤1 Point) During OL	0 participants	0 participants	—	—	—	—

SECONDARY outcome

Timeframe: Last Study Visit (Day OL-729)

Population: Due to the early termination of the study after preliminary IP1C results were reviewed and the primary efficacy endpoint was not achieved, the secondary subgroup analyses of clinical efficacy upon retreatment with abatacept among participants who received study drug during the IP or MP was not conducted for the OL as planned.

The Mayo Scoring system (range 0-12 points, high scores=greater severity of disease) is a composite index consisting of 4 disease variables (stool frequency, rectal bleeding, endoscopy evaluation, and Physician's Global Assessment). Clinical response=reduction from baseline in the Mayo score of ≥ 3 points and ≥ 30%, with accompanying decrease in the rectal bleeding subscore of ≥ 1 point or absolute rectal bleeding subscore of ≤ 1 point. Clinical remission = Mayo score of ≤ 2 points with no individual subscore exceeding 1 point. Change from Baseline= post-Baseline - Baseline value.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: For participants receiving OL medication, all measurements starting after Day OL-1 (including follow-up visits and at 56 and 85 days after last dose)

Outcome measures

Outcome measures
Measure	IP1C-ABA 30/~10 mg/kg n=324 Participants During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg.	IP1C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29,and IP-57 at a dose of \~10 mg/kg (weight-tiered).	IP1C-ABA 3 mg/kg During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	IP1C-Placebo During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	IP Cohort 2 (IP2C)-ABA 30/~10 mg/kg During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). Following this, on Days IP-29 and IP-57 abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	IP2C-ABA ~10 mg/kg During IP, abatacept was administered IV on Days IP-1 and IP-15 at a dose of \~10 mg/kg (weight-tiered). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).
OL; Number of Participants With Abatacept-Induced Antibodies Total	66 participants	—	—	—	—	—
OL; Number of Participants With Abatacept-Induced Antibodies CTLA4/Possibly Ig	59 participants	—	—	—	—	—
OL; Number of Participants With Abatacept-Induced Antibodies Ig and/or Ig Junction	11 participants	—	—	—	—	—

SECONDARY outcome

Timeframe: Day OL-1 through Day OL-729

Population: Due to the early termination of the study after preliminary IP1C results were reviewed and the primary efficacy endpoint was not achieved, the secondary subgroup analyses of corticosteroid use was not conducted for the OL as planned.

Participants taking oral corticosteroids (equivalent of ≤ 30 mg prednisone daily) must have met minimum treatment duration at entry into IP and had stable dose for ≥2 weeks prior to entry into the IP.

Outcome measures

Outcome data not reported

Adverse Events

ABA 30/~10 mg/kg,IP1C

Serious events: 22 serious events

Other events: 49 other events

Deaths: 0 deaths

ABA 30/~10mg/kg,IP2C

Serious events: 6 serious events

Other events: 13 other events

Deaths: 0 deaths

ABA 3 mg/kg,IP1C

Serious events: 8 serious events

Other events: 21 other events

Deaths: 0 deaths

ABA ~10 mg/kg,IP1C

Serious events: 20 serious events

Other events: 48 other events

Deaths: 0 deaths

ABA ~10mg/kg,IP2C

Serious events: 4 serious events

Other events: 13 other events

Deaths: 0 deaths

ABA ~10mg/kg, MP

Serious events: 7 serious events

Other events: 20 other events

Deaths: 0 deaths

ABA ~10 mg/kg, OL

Serious events: 66 serious events

Other events: 137 other events

Deaths: 0 deaths

Placebo, IP1C

Serious events: 7 serious events

Other events: 45 other events

Deaths: 0 deaths

Placebo, MP

Serious events: 4 serious events

Other events: 24 other events

Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure	ABA 30/~10 mg/kg,IP1C n=141 participants at risk During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	ABA 30/~10mg/kg,IP2C n=51 participants at risk During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg.	ABA 3 mg/kg,IP1C n=70 participants at risk During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	ABA ~10 mg/kg,IP1C n=139 participants at risk During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29, and IP-57 at a dose of \~10 mg/kg (weight-tiered).	ABA ~10mg/kg,IP2C n=50 participants at risk During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29, and IP-57 at a dose of \~10 mg/kg (weight-tiered).	ABA ~10mg/kg, MP n=65 participants at risk During MP, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered) every 28 days beginning Day MP-1.	ABA ~10 mg/kg, OL n=349 participants at risk During OL, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered) every 28 days beginning Day OL-1.	Placebo, IP1C n=140 participants at risk During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	Placebo, MP n=66 participants at risk During the MP, placebo was administered IV every 28 days beginning Day MP-1 through Day MP-337.
Eye disorders VISION BLURRED	0.71% 1/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Investigations HAEMOGLOBIN DECREASED	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Investigations HEPATIC ENZYME INCREASED	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.71% 1/140	0.00% 0/66
Cardiac disorders MYOCARDIAL INFARCTION	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Cardiac disorders ACUTE CORONARY SYNDROME	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Vascular disorders DEEP VEIN THROMBOSIS	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.72% 1/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Vascular disorders FEMORAL ARTERIAL STENOSIS	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Psychiatric disorders ABNORMAL BEHAVIOUR	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Psychiatric disorders PERSONALITY CHANGE	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Hepatobiliary disorders CHOLECYSTITIS	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.72% 1/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Hepatobiliary disorders HEPATIC FUNCTION ABNORMAL	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Immune system disorders HYPERSENSITIVITY	0.71% 1/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Immune system disorders ANAPHYLACTIC REACTION	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.71% 1/140	0.00% 0/66
Nervous system disorders DIZZINESS	0.71% 1/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Nervous system disorders CEREBRAL ISCHAEMIA	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Gastrointestinal disorders COLITIS	0.00% 0/141	0.00% 0/51	0.00% 0/70	1.4% 2/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Gastrointestinal disorders DIARRHOEA	1.4% 2/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.57% 2/349	0.00% 0/140	0.00% 0/66
Gastrointestinal disorders PROCTALGIA	0.71% 1/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Gastrointestinal disorders PANCREATITIS	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Gastrointestinal disorders ABDOMINAL PAIN	0.00% 0/141	2.0% 1/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Gastrointestinal disorders CROHN'S DISEASE	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.72% 1/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Gastrointestinal disorders COLITIS ULCERATIVE	9.2% 13/141	9.8% 5/51	7.1% 5/70	10.1% 14/139	8.0% 4/50	4.6% 3/65	12.0% 42/349	2.9% 4/140	1.5% 1/66
Gastrointestinal disorders RECTAL HAEMORRHAGE	0.71% 1/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Gastrointestinal disorders ABDOMINAL PAIN LOWER	0.00% 0/141	0.00% 0/51	1.4% 1/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Gastrointestinal disorders ABDOMINAL PAIN UPPER	0.00% 0/141	2.0% 1/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Infections and infestations SEPSIS	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	1.5% 1/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Infections and infestations VIRAEMIA	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	1.5% 1/66
Infections and infestations PNEUMONIA	0.71% 1/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	1.5% 1/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Infections and infestations SINUSITIS	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Infections and infestations VARICELLA	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	1.5% 1/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Infections and infestations LISTERIOSIS	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Infections and infestations ANAL ABSCESS	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	1.5% 1/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Infections and infestations APPENDICITIS	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	1.5% 1/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Infections and infestations OTITIS MEDIA	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Infections and infestations SEPTIC SHOCK	0.71% 1/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Infections and infestations HERPES ZOSTER	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Infections and infestations HIV INFECTION	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Infections and infestations PILONIDAL CYST	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Infections and infestations GASTROENTERITIS	0.71% 1/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Infections and infestations LOBAR PNEUMONIA	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Infections and infestations VIRAL INFECTION	0.00% 0/141	0.00% 0/51	1.4% 1/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Infections and infestations PELVIC INFECTION	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Infections and infestations ABDOMINAL ABSCESS	1.4% 2/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Infections and infestations OTITIS MEDIA CHRONIC	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	1.5% 1/66
Infections and infestations CLOSTRIDIAL INFECTION	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	1.5% 1/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Infections and infestations PNEUMONIA HERPES VIRAL	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	1.5% 1/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Infections and infestations CYTOMEGALOVIRUS COLITIS	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Infections and infestations URINARY TRACT INFECTION	0.71% 1/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Infections and infestations CLOSTRIDIUM DIFFICILE COLITIS	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Renal and urinary disorders NEPHROLITHIASIS	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.57% 2/349	0.00% 0/140	0.00% 0/66
Renal and urinary disorders RENAL IMPAIRMENT	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Renal and urinary disorders GLOMERULONEPHRITIS	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Renal and urinary disorders RENAL FAILURE ACUTE	0.71% 1/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Metabolism and nutrition disorders DEHYDRATION	0.71% 1/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.71% 1/140	0.00% 0/66
Metabolism and nutrition disorders MALNUTRITION	0.71% 1/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Blood and lymphatic system disorders ANAEMIA	1.4% 2/141	2.0% 1/51	0.00% 0/70	0.72% 1/139	0.00% 0/50	0.00% 0/65	0.57% 2/349	0.00% 0/140	0.00% 0/66
Blood and lymphatic system disorders IRON DEFICIENCY ANAEMIA	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Skin and subcutaneous tissue disorders PYODERMA GANGRENOSUM	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Reproductive system and breast disorders UTERINE POLYP	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Injury, poisoning and procedural complications ALCOHOL POISONING	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Injury, poisoning and procedural complications ARTERIAL RESTENOSIS	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Injury, poisoning and procedural complications ABDOMINAL WOUND DEHISCENCE	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.72% 1/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Musculoskeletal and connective tissue disorders BACK PAIN	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Musculoskeletal and connective tissue disorders ARTHRALGIA	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Musculoskeletal and connective tissue disorders FIBROMYALGIA	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.72% 1/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Respiratory, thoracic and mediastinal disorders PNEUMOTHORAX	0.71% 1/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Respiratory, thoracic and mediastinal disorders ACUTE RESPIRATORY FAILURE	0.71% 1/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
General disorders MALAISE	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
General disorders PYREXIA	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
General disorders ASTHENIA	0.00% 0/141	0.00% 0/51	1.4% 1/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
General disorders INFUSION RELATED REACTION	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.72% 1/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	0.00% 0/66
Neoplasms benign, malignant and unspecified (incl cysts and polyps) BREAST CANCER	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.00% 0/140	1.5% 1/66
Neoplasms benign, malignant and unspecified (incl cysts and polyps) BOWEN'S DISEASE	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Neoplasms benign, malignant and unspecified (incl cysts and polyps) MALIGNANT MELANOMA	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.00% 0/349	0.71% 1/140	0.00% 0/66
Neoplasms benign, malignant and unspecified (incl cysts and polyps) BASAL CELL CARCINOMA	0.71% 1/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.57% 2/349	0.00% 0/140	0.00% 0/66
Neoplasms benign, malignant and unspecified (incl cysts and polyps) CHRONIC MYELOID LEUKAEMIA	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66
Neoplasms benign, malignant and unspecified (incl cysts and polyps) SQUAMOUS CELL CARCINOMA OF SKIN	0.00% 0/141	0.00% 0/51	0.00% 0/70	0.00% 0/139	0.00% 0/50	0.00% 0/65	0.29% 1/349	0.00% 0/140	0.00% 0/66

Other adverse events

Other adverse events
Measure	ABA 30/~10 mg/kg,IP1C n=141 participants at risk During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered).	ABA 30/~10mg/kg,IP2C n=51 participants at risk During IP, abatacept was administered intravenously (IV) on Days IP-1 and IP-15 at a dose of 30 mg/kg (fixed dose). On Days IP-29 and IP-57, abatacept was administered IV at a dose of \~10 mg/kg.	ABA 3 mg/kg,IP1C n=70 participants at risk During IP, abatacept was administered IV on Days IP-1, IP-15, IP-29, and IP-57 at a dose of 3 mg/kg (fixed dose).	ABA ~10 mg/kg,IP1C n=139 participants at risk During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29, and IP-57 at a dose of \~10 mg/kg (weight-tiered).	ABA ~10mg/kg,IP2C n=50 participants at risk During IP, abatacept was administered IV on Days IP-1,IP-15, IP-29, and IP-57 at a dose of \~10 mg/kg (weight-tiered).	ABA ~10mg/kg, MP n=65 participants at risk During MP, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered) every 28 days beginning Day MP-1.	ABA ~10 mg/kg, OL n=349 participants at risk During OL, abatacept was administered IV at a dose of \~10 mg/kg (weight-tiered) every 28 days beginning Day OL-1.	Placebo, IP1C n=140 participants at risk During the IP, placebo was administered IV on Days IP-1, IP-15, IP-29, and IP-57.	Placebo, MP n=66 participants at risk During the MP, placebo was administered IV every 28 days beginning Day MP-1 through Day MP-337.
Nervous system disorders HEADACHE	12.1% 17/141	5.9% 3/51	10.0% 7/70	8.6% 12/139	12.0% 6/50	4.6% 3/65	6.9% 24/349	8.6% 12/140	7.6% 5/66
Nervous system disorders DIZZINESS	2.8% 4/141	2.0% 1/51	5.7% 4/70	1.4% 2/139	0.00% 0/50	0.00% 0/65	2.0% 7/349	2.1% 3/140	4.5% 3/66
Gastrointestinal disorders NAUSEA	5.7% 8/141	2.0% 1/51	4.3% 3/70	7.9% 11/139	6.0% 3/50	3.1% 2/65	5.2% 18/349	6.4% 9/140	6.1% 4/66
Gastrointestinal disorders ABDOMINAL PAIN	5.7% 8/141	3.9% 2/51	1.4% 1/70	0.72% 1/139	6.0% 3/50	4.6% 3/65	4.6% 16/349	3.6% 5/140	6.1% 4/66
Infections and infestations INFLUENZA	0.71% 1/141	2.0% 1/51	0.00% 0/70	2.2% 3/139	0.00% 0/50	6.2% 4/65	3.4% 12/349	2.1% 3/140	1.5% 1/66
Infections and infestations NASOPHARYNGITIS	3.5% 5/141	3.9% 2/51	2.9% 2/70	2.2% 3/139	2.0% 1/50	4.6% 3/65	8.3% 29/349	5.7% 8/140	4.5% 3/66
Infections and infestations URINARY TRACT INFECTION	3.5% 5/141	3.9% 2/51	4.3% 3/70	2.9% 4/139	6.0% 3/50	0.00% 0/65	3.2% 11/349	0.71% 1/140	1.5% 1/66
Infections and infestations UPPER RESPIRATORY TRACT INFECTION	2.1% 3/141	2.0% 1/51	1.4% 1/70	1.4% 2/139	0.00% 0/50	3.1% 2/65	6.3% 22/349	3.6% 5/140	3.0% 2/66
Musculoskeletal and connective tissue disorders BACK PAIN	2.1% 3/141	2.0% 1/51	0.00% 0/70	1.4% 2/139	0.00% 0/50	6.2% 4/65	3.7% 13/349	2.1% 3/140	7.6% 5/66
Musculoskeletal and connective tissue disorders ARTHRALGIA	2.8% 4/141	2.0% 1/51	2.9% 2/70	4.3% 6/139	0.00% 0/50	3.1% 2/65	5.2% 18/349	2.9% 4/140	7.6% 5/66
Respiratory, thoracic and mediastinal disorders COUGH	4.3% 6/141	2.0% 1/51	2.9% 2/70	2.9% 4/139	2.0% 1/50	6.2% 4/65	3.7% 13/349	2.1% 3/140	7.6% 5/66
General disorders FATIGUE	4.3% 6/141	5.9% 3/51	4.3% 3/70	5.8% 8/139	6.0% 3/50	1.5% 1/65	4.6% 16/349	2.1% 3/140	3.0% 2/66
General disorders PYREXIA	6.4% 9/141	5.9% 3/51	8.6% 6/70	4.3% 6/139	2.0% 1/50	3.1% 2/65	4.9% 17/349	1.4% 2/140	1.5% 1/66
General disorders ASTHENIA	5.7% 8/141	0.00% 0/51	1.4% 1/70	2.9% 4/139	0.00% 0/50	0.00% 0/65	1.7% 6/349	1.4% 2/140	1.5% 1/66

Additional Information

BMS Study Director

Bristol-Myers Squibb

Email: [email protected]

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