Abatacept side effects: what 137,367 FDA adverse event reports show

Abatacept · Orencia · 1,285 reaction terms · 1,020,397 drug–reaction co-reports · data 2026-09-14

Drug class

Selective T Cell Costimulation Modulator

FDA label (Established Pharmacologic Class)

Brand names

Orencia

openFDA label

Who reports

137,367 reports · 60% serious · 9,239 with death outcome · 85% female

openFDA FAERS counts, all years, deduplication not applied

Used for

ORENCIA is a selective T cell costimulation modulator indicated for: • the treatment of adult patients with moderately to severely active rheumatoid arthritis (RA). (1.1) • the treatment of patients 2 years of age and older with moderately to severely active polyarticular juvenile idiopathic arthritis (pJIA). (1.2) • the treatment of patients 2 years of age and older with active psoriatic arthritis (PsA).

FDA label, Indications and Usage

What it is

Abatacept is a selective T-cell costimulation modulator. Abatacept is a soluble fusion protein that consists of the extracellular domain of human cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) linked to the modified Fc (hinge, CH2, and CH3 domains) portion of human immunoglobulin G1 (IgG1).

FDA label, Description section

Boxed warning

None in the current label

How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation. Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)? That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.

Causality screen of the 40 strongest signals

Likely indication confounding 1Reporting / coding artifact 4Lab value / disease marker 11Not in label — unassessed 24

What the badges mean

Likely indication confounding The term appears in the label's indications: reports probably describe the disease being treated (or its progression), not a drug effect. Classic confounding by indication.
Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.

Strongest disproportionality signals

Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 1,245 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.

Show: hide coding/lab/outcome terms hide indication terms unlabeled only hide PRR-only

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Human antichimeric antibody positive	306	1,575.3 1,076.5–2,305.4ROR 1,578.8 · χ² 41,541 / p <1e-300	136.1 EB05 123.8 · IC025 +6.6 3/3 methods agree	Lab value / disease marker	serious n=306	not reported in cached trials
Rheumatoid factor negative	137	538.3 375.8–771.0ROR 538.8 · χ² 15,836 / p <1e-300	115.8 EB05 100.4 · IC025 +6.1 3/3 methods agree	Reporting / coding artifact	serious n=137 · ♀ 45% (drug 85%) · 100% clinician	not reported in cached trials
Anti-cyclic citrullinated peptide antibody positive	5,434	513.1 485.3–542.6ROR 534.2 · χ² 626,086 / p <1e-300	116.4 EB05 113.8 · IC025 +6.8 3/3 methods agree	Lab value / disease marker	serious PRR 111.7 · 93% clinician	not reported in cached trials
Rheumatoid factor positive	4,277	450.3 424.2–478.1ROR 464.7 · χ² 477,442 / p <1e-300	112.8 EB05 110.0 · IC025 +6.7 3/3 methods agree	Lab value / disease marker	serious n=4,274 · 92% clinician	not reported in cached trials
Anti-cyclic citrullinated peptide antibody	486	419.4 352.6–498.8ROR 420.9 · χ² 53,147 / p <1e-300	110.4 EB05 102.4 · IC025 +6.5 3/3 methods agree	Lab value / disease marker	serious n=485 · 95% clinician	not reported in cached trials
Red blood cell sedimentation rate	205	419.3 321.0–547.6ROR 419.9 · χ² 22,351 / p <1e-300	109.7 EB05 97.7 · IC025 +6.2 3/3 methods agree	Lab value / disease marker	serious n=205 · 91% clinician	not reported in cached trials
Swollen joint count increased	2,226	389.6 360.1–421.5ROR 396.0 · χ² 238,960 / p <1e-300	108.6 EB05 104.8 · IC025 +6.7 3/3 methods agree	Lab value / disease marker	serious n=2,220 · 96% clinician	not reported in cached trials
Pemphigus	8,847	385.9 371.1–401.3ROR 412.3 · χ² 947,876 / p <1e-300	108.3 EB05 106.5 · IC025 +6.7 3/3 methods agree	Not in label — unassessed	serious PRR 104.0	not reported in cached trials
Device safety feature issue	669	364.5 316.7–419.5ROR 366.3 · χ² 70,367 / p <1e-300	106.3 EB05 99.7 · IC025 +6.5 3/3 methods agree	Reporting / coding artifact	serious n=586	not reported in cached trials
Rheumatic fever	2,990	337.7 316.6–360.2ROR 345.1 · χ² 307,667 / p <1e-300	104.1 EB05 101.1 · IC025 +6.6 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious n=2,989 · 94% clinician	not reported in cached trials
Red blood cell sedimentation rate abnormal	1,502	282.1 258.9–307.3ROR 285.2 · χ² 145,512 / p <1e-300	98.2 EB05 94.1 · IC025 +6.5 3/3 methods agree	Lab value / disease marker	serious n=1,497	not reported in cached trials
Lupus vulgaris	763	276.5 245.3–311.7ROR 278.0 · χ² 73,344 / p <1e-300	97.4 EB05 91.7 · IC025 +6.4 3/3 methods agree	Not in label — unassessed	serious n=763 · 96% clinician	not reported in cached trials
Duodenal ulcer perforation	4,534	249.6 238.1–261.7ROR 258.1 · χ² 420,226 / p <1e-300	94.0 EB05 91.7 · IC025 +6.5 3/3 methods agree	Not in label — unassessed	serious PRR 89.9 · 94% clinician	not reported in cached trials
Granuloma skin	504	239.6 208.2–275.9ROR 240.5 · χ² 45,885 / p <1e-300	92.3 EB05 85.7 · IC025 +6.3 3/3 methods agree	Not in label — unassessed	serious n=503	not reported in cached trials
Deep vein thrombosis postoperative	1,171	228.5 208.7–250.3ROR 230.5 · χ² 104,741 / p <1e-300	90.8 EB05 86.5 · IC025 +6.4 3/3 methods agree	Not in label — unassessed	serious n=1,171 · 94% clinician	not reported in cached trials
Hepatic enzyme	83	225.3 160.2–316.8ROR 225.4 · χ² 7,297 / p <1e-300	88.6 EB05 73.7 · IC025 +5.5 3/3 methods agree	Not in label — unassessed	serious n=83 · 100% clinician	NCT00559585: 1/731 (0.1%) on Abatacept (serious AE)
Hand deformity	7,748	224.0 216.3–231.9ROR 237.3 · χ² 688,223 / p <1e-300	90.2 EB05 88.5 · IC025 +6.4 3/3 methods agree	Not in label — unassessed	serious PRR 93.4	not reported in cached trials
Grip strength	134	210.6 161.9–273.9ROR 210.8 · χ² 11,508 / p <1e-300	86.9 EB05 75.2 · IC025 +5.8 3/3 methods agree	Not in label — unassessed	serious n=134 · 100% clinician	not reported in cached trials
Musculoskeletal deformity	136	209.3 161.3–271.6ROR 209.5 · χ² 11,651 / p <1e-300	86.7 EB05 75.1 · IC025 +5.8 3/3 methods agree	Not in label — unassessed	serious n=136 · 100% clinician	not reported in cached trials
Synovitis	10,370	208.0 202.0–214.2ROR 224.9 · χ² 893,390 / p <1e-300	87.5 EB05 86.1 · IC025 +6.4 3/3 methods agree	Not in label — unassessed	serious PRR 87.5	NCT00559585: 2/731 (0.3%) on Abatacept (serious AE)
C-reactive protein abnormal	3,681	207.9 197.9–218.5ROR 213.6 · χ² 316,822 / p <1e-300	87.4 EB05 85.1 · IC025 +6.4 3/3 methods agree	Lab value / disease marker	serious n=3,678	not reported in cached trials
C-reactive protein	516	202.7 177.6–231.4ROR 203.5 · χ² 43,844 / p <1e-300	86.3 EB05 80.2 · IC025 +6.2 3/3 methods agree	Lab value / disease marker	serious n=516 · 95% clinician	not reported in cached trials
Facet joint syndrome	1,671	173.1 161.4–185.7ROR 175.2 · χ² 132,353 / p <1e-300	80.6 EB05 77.4 · IC025 +6.2 3/3 methods agree	Not in label — unassessed	serious n=1,671 · 94% clinician	NCT00559585: 1/744 (0.1%) on Abatacept (serious AE)
Swollen joint count	122	150.5 117.1–193.6ROR 150.7 · χ² 8,949 / p <1e-300	74.6 EB05 64.1 · IC025 +5.6 3/3 methods agree	Not in label — unassessed	serious n=122 · 100% clinician	not reported in cached trials
Atlantoaxial instability	54	144.0 99.1–209.2ROR 144.0 · χ² 3,830 / p <1e-300	72.0 EB05 57.3 · IC025 +5.0 3/3 methods agree	Not in label — unassessed	serious n=54 · ♀ 0% (drug 85%) · 100% clinician	not reported in cached trials
Body height below normal	315	143.8 123.2–167.9ROR 144.1 · χ² 22,682 / p <1e-300	73.4 EB05 66.9 · IC025 +5.9 3/3 methods agree	Reporting / coding artifact	serious n=315	not reported in cached trials
Muscle injury	3,966	143.2 137.1–149.5ROR 147.4 · χ² 285,883 / p <1e-300	73.6 EB05 71.7 · IC025 +6.1 3/3 methods agree	Not in label — unassessed	serious PRR 76.2 · 94% clinician	not reported in cached trials
Presbyacusis	147	137.2 109.7–171.6ROR 137.3 · χ² 10,285 / p <1e-300	71.3 EB05 62.2 · IC025 +5.6 3/3 methods agree	Not in label — unassessed	serious n=147	not reported in cached trials
X-ray abnormal	843	137.0 124.7–150.3ROR 137.8 · χ² 59,272 / p <1e-300	71.8 EB05 67.8 · IC025 +6.0 3/3 methods agree	Lab value / disease marker	serious n=843 · 92% clinician	not reported in cached trials
Contraindicated product administered	14,008	132.7 129.8–135.7ROR 147.6 · χ² 970,680 / p <1e-300	70.7 EB05 69.7 · IC025 +6.1 3/3 methods agree	Reporting / coding artifact	serious PRR 81.8	not reported in cached trials
Helicobacter infection	4,729	132.4 127.4–137.6ROR 137.1 · χ² 326,916 / p <1e-300	70.6 EB05 68.9 · IC025 +6.1 3/3 methods agree	Not in label — unassessed	serious PRR 71.4 · 93% clinician	not reported in cached trials
Adjustment disorder with depressed mood	935	132.3 121.2–144.5ROR 133.2 · χ² 64,536 / p <1e-300	70.5 EB05 66.8 · IC025 +6.0 3/3 methods agree	Not in label — unassessed	serious n=935 · 95% clinician	not reported in cached trials
Sleep disorder due to general medical condition, insomnia type	2,944	128.9 122.7–135.3ROR 131.7 · χ² 200,460 / p <1e-300	69.6 EB05 67.5 · IC025 +6.0 3/3 methods agree	Not in label — unassessed	serious n=2,942 · 94% clinician	not reported in cached trials
Dislocation of vertebra	1,010	127.1 116.9–138.2ROR 128.1 · χ² 68,204 / p <1e-300	69.0 EB05 65.5 · IC025 +6.0 3/3 methods agree	Not in label — unassessed	serious n=1,010 · 94% clinician	NCT00559585: 1/731 (0.1%) on Abatacept (serious AE)
Joint laxity	129	113.3 90.1–142.4ROR 113.4 · χ² 8,099 / p <1e-300	64.3 EB05 55.5 · IC025 +5.4 3/3 methods agree	Not in label — unassessed	serious n=128	not reported in cached trials
Folliculitis	4,372	112.1 107.8–116.5ROR 115.7 · χ² 275,013 / p <1e-300	64.4 EB05 62.8 · IC025 +5.9 3/3 methods agree	Not in label — unassessed	serious PRR 72.4 · 94% clinician	not reported in cached trials
Anticipatory anxiety	109	103.0 80.7–131.5ROR 103.1 · χ² 6,455 / p <1e-300	60.7 EB05 51.8 · IC025 +5.3 3/3 methods agree	Not in label — unassessed	serious n=109	not reported in cached trials
Blood parathyroid hormone decreased	595	101.3 91.3–112.4ROR 101.7 · χ² 35,144 / p <1e-300	60.6 EB05 56.7 · IC025 +5.7 3/3 methods agree	Lab value / disease marker	serious n=595	not reported in cached trials
Bone erosion	1,361	95.1 88.9–101.8ROR 96.1 · χ² 77,382 / p <1e-300	58.4 EB05 55.9 · IC025 +5.8 3/3 methods agree	Not in label — unassessed	serious n=1,355	not reported in cached trials
Elbow deformity	132	93.0 74.8–115.5ROR 93.0 · χ² 7,343 / p <1e-300	57.2 EB05 49.5 · IC025 +5.3 3/3 methods agree	Not in label — unassessed	serious n=132	not reported in cached trials

Trial evidence (ClinicalTrials.gov)

✓ Trial adverse-event data found on ClinicalTrials.gov

Largest completed trials with posted results that list Abatacept as a study intervention. The right-hand column of the signal table shows whether each FAERS term was also recorded in these trials, with a real denominator (4 of 40 signal terms matched).

NCT00559585 — Methotrexate-Inadequate Response Study (N=2492, PHASE3; 367 AE terms posted; arms: IV Abatacept; SC Abatacept)
NCT04593940 — Immune Modulators for Treating COVID-19 (N=1971, PHASE3; 15 AE terms posted; arms: Standard of Care + Infliximab; Standard of Care + Infliximab Matching P; Standard of Care + Abatacept; Standard of Care + Abatacept Matching Pl)

Caveats: trial populations, doses and follow-up differ from the reporting population; AE terms are sponsor-coded and matched here by wording; absence from a trial list means the term was not reported above the sponsor's frequency threshold, not that it cannot occur.

Most frequently reported reactions

By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Drug ineffective (drug did not work)	38,998	4.6 4.6–4.7ROR 6.1 · χ² 114,473 / p <1e-300	4.5 EB05 4.5 · IC025 +2.2 3/3 methods agree	Reporting / coding artifact	serious PRR 9.5	not reported in cached trials
Rheumatoid arthritis	24,346	41.7 41.1–42.2ROR 50.4 · χ² 759,500 / p <1e-300	32.8 EB05 32.4 · IC025 +5.0 3/3 methods agree	Likely indication confounding term in indications	serious PRR 35.0	NCT00559585: 14/744 (1.9%) on Abatacept (serious AE)
Pain	21,928	5.6 5.5–5.7ROR 6.5 · χ² 82,147 / p <1e-300	5.4 EB05 5.4 · IC025 +2.4 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 6.6	NCT00559585: 4/744 (0.5%) on Abatacept (serious AE)
Arthralgia (joint pain)	21,293	8.2 8.1–8.3ROR 9.5 · χ² 130,207 / p <1e-300	7.8 EB05 7.7 · IC025 +2.9 3/3 methods agree	Not in label — unassessed	serious PRR 8.3	NCT00559585: 2/744 (0.3%) on Abatacept (serious AE)
Joint swelling	20,569	31.2 30.8–31.7ROR 36.5 · χ² 500,692 / p <1e-300	26.0 EB05 25.7 · IC025 +4.7 3/3 methods agree	Not in label — unassessed	serious PRR 28.3	not reported in cached trials
Fatigue (tiredness)	14,480	2.9 2.8–2.9ROR 3.1 · χ² 18,030 / p <1e-300	2.8 EB05 2.8 · IC025 +1.5 3/3 methods agree	Not in label — unassessed	serious PRR 4.7	not reported in cached trials
Contraindicated product administered	14,008	132.7 129.8–135.7ROR 147.6 · χ² 970,680 / p <1e-300	70.7 EB05 69.7 · IC025 +6.1 3/3 methods agree	Reporting / coding artifact	serious PRR 81.8	not reported in cached trials
Rash	13,296	4.8 4.7–4.9ROR 5.2 · χ² 39,420 / p <1e-300	4.7 EB05 4.6 · IC025 +2.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 9.2	not reported in cached trials
Drug intolerance	13,209	24.1 23.7–24.5ROR 26.6 · χ² 253,123 / p <1e-300	20.9 EB05 20.6 · IC025 +4.4 3/3 methods agree	Reporting / coding artifact	serious PRR 32.2	not reported in cached trials
Off label use (used outside approved label)	12,112	2.1 2.1–2.2ROR 2.3 · χ² 7,581 / p <1e-300	2.1 EB05 2.1 · IC025 +1.1 3/3 methods agree	Reporting / coding artifact	serious PRR 3.6	not reported in cached trials
Arthropathy	11,761	40.6 39.8–41.4ROR 44.3 · χ² 357,774 / p <1e-300	32.1 EB05 31.6 · IC025 +5.0 3/3 methods agree	Not in label — unassessed	serious PRR 37.1	not reported in cached trials
Alopecia (hair loss)	10,696	8.7 8.5–8.9ROR 9.4 · χ² 69,554 / p <1e-300	8.3 EB05 8.1 · IC025 +3.0 3/3 methods agree	Not in label — unassessed	serious PRR 16.1	not reported in cached trials
Synovitis	10,370	208.0 202.0–214.2ROR 224.9 · χ² 893,390 / p <1e-300	87.5 EB05 86.1 · IC025 +6.4 3/3 methods agree	Not in label — unassessed	serious PRR 87.5	NCT00559585: 2/731 (0.3%) on Abatacept (serious AE)
Abdominal discomfort	10,200	9.8 9.7–10.0ROR 10.5 · χ² 76,602 / p <1e-300	9.3 EB05 9.1 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 19.4	not reported in cached trials
Treatment failure	9,897	20.8 20.4–21.2ROR 22.3 · χ² 164,205 / p <1e-300	18.4 EB05 18.1 · IC025 +4.2 3/3 methods agree	Reporting / coding artifact	serious PRR 32.2	not reported in cached trials

Unlabeled candidate signals

These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.

Pemphigus — n=8,847, PRR 385.9
Lupus vulgaris — n=763, PRR 276.5
Duodenal ulcer perforation — n=4,534, PRR 249.6
Granuloma skin — n=504, PRR 239.6
Deep vein thrombosis postoperative — n=1,171, PRR 228.5
Hepatic enzyme — n=83, PRR 225.3 (also seen in trial arm)
Hand deformity — n=7,748, PRR 224.0
Grip strength — n=134, PRR 210.6
Musculoskeletal deformity — n=136, PRR 209.3
Synovitis — n=10,370, PRR 208.0 (also seen in trial arm)

Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.

Common questions

What are the most reported side effects of Abatacept?

In FDA FAERS, the most frequently co-reported reaction terms for Abatacept are rheumatoid arthritis, pain, arthralgia, joint swelling, fatigue, rash. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.

Does Abatacept have an FDA boxed warning?

No. The FDA label retrieved for Abatacept has no boxed warning; see the label's Warnings and Precautions for the recognised risks.

Do FAERS signals prove that Abatacept causes these side effects?

No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.

Sources & methods

FDA label via openFDA (set ID 0836c6ac-ee37-5640-2fed-a3185a0b16eb, effective 20251113; matched on openfda.generic_name.exact:"ABATACEPT" AND openfda.product_type:"HUMAN PRESCRIPTION DRUG")
Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA count= aggregation, field patient.drug.openfda.generic_name.exact, 1,285 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction
Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
Seriousness and sex counts from openFDA count=serious, patient.patientsex, seriousnessdeath
ClinicalTrials.gov API v2 (query ABATACEPT, results-bearing studies sorted by enrollment)

Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.