Belatacept side effects: what 4,646 FDA adverse event reports show

Belatacept · Nulojix · 118 reaction terms · 3,928 drug–reaction co-reports · data 2026-09-14

Drug class

Selective T Cell Costimulation Blocker

FDA label (Established Pharmacologic Class)

Brand names

Nulojix

openFDA label

Who reports

4,646 reports · 76% serious · 742 with death outcome · 41% female

openFDA FAERS counts, all years, deduplication not applied

Used for

• NULOJIX is a selective T cell costimulation blocker indicated for prophylaxis of organ rejection in adult patients receiving a kidney transplant. (1.1) • Use in combination with basiliximab induction, mycophenolate mofetil, and corticosteroids. (1.1) Limitations of Use : • Use only in patients who are EBV seropositive.

FDA label, Indications and Usage

What it is

NULOJIX ® (belatacept), a selective T cell costimulation blocker, is a soluble fusion protein consisting of the modified extracellular domain of CTLA-4 fused to a portion (hinge-CH2-CH3 domains) of the Fc domain of a human immunoglobulin G1 antibody.

FDA label, Description section

Boxed warning

POST-TRANSPLANT LYMPHOPROLIFERATIVE DISORDER, OTHER MALIGNANCIES, AND SERIOUS INFECTIONS Increased risk for developing post-transplant lymphoproliferative disorder (PTLD), predominantly involving the central nervous system (CNS).

FDA 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

Labeled adverse reaction 6Labeled (related wording) 5Reporting / coding artifact 4Outcome field, not a reaction 1Not in label — unassessed 24

What the badges mean

Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
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.
Outcome field, not a reaction Death is a report outcome, not a reaction term. It is dominated by the underlying illness; see the seriousness profile and the boxed warning instead.
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. 78 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
Cytomegalovirus infection	180	49.3 42.7–57.0ROR 51.3 · χ² 8,386 / p <1e-300	48.5 EB05 42.9 · IC025 +5.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 36.3 · 93% clinician	no trial data cached
Thrombotic microangiopathy	104	48.9 40.4–59.2ROR 50.0 · χ² 4,784 / p <1e-300	48.0 EB05 40.7 · IC025 +5.0 3/3 methods agree	Not in label — unassessed	serious PRR 36.3 · 96% clinician	no trial data cached
Pneumocystis jirovecii pneumonia	85	38.7 31.3–47.8ROR 39.4 · χ² 3,056 / p <1e-300	38.0 EB05 31.7 · IC025 +4.6 3/3 methods agree	Not in label — unassessed	serious PRR 29.1 · 93% clinician	no trial data cached
Product preparation error	86	18.8 15.2–23.2ROR 19.1 · χ² 1,427 / p <1e-300	18.6 EB05 15.6 · IC025 +3.7 3/3 methods agree	Reporting / coding artifact	95% clinician	no trial data cached
Renal tubular necrosis	36	16.6 12.0–22.9ROR 16.7 · χ² 509 / p 5e-113	16.3 EB05 12.2 · IC025 +3.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 12.6 · 91% clinician	no trial data cached
Nephropathy toxic	36	14.6 10.6–20.2ROR 14.7 · χ² 442 / p 2e-98	14.3 EB05 10.6 · IC025 +3.1 3/3 methods agree	Labeled (related wording) related wording	serious PRR 11.3 · ♀ 62% (drug 41%) · 94% clinician	no trial data cached
Posterior reversible encephalopathy syndrome	30	14.3 10.0–20.4ROR 14.3 · χ² 356 / p 1e-79	13.9 EB05 9.9 · IC025 +2.9 3/3 methods agree	Not in label — unassessed	serious PRR 10.8 · 100% clinician	no trial data cached
Urosepsis	24	11.8 7.9–17.5ROR 11.8 · χ² 225 / p 3e-51	11.0 EB05 7.4 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 8.9 · 92% clinician	no trial data cached
Bacteraemia	28	10.7 7.4–15.6ROR 10.8 · χ² 237 / p 7e-54	10.0 EB05 7.0 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 8.2 · 96% clinician	no trial data cached
Incorrect product storage	30	10.2 7.1–14.5ROR 10.2 · χ² 239 / p 4e-54	9.5 EB05 6.8 · IC025 +2.5 3/3 methods agree	Reporting / coding artifact	100% clinician	no trial data cached
Clostridium difficile colitis	22	9.4 6.2–14.2ROR 9.4 · χ² 156 / p 5e-36	8.4 EB05 5.6 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 6.9 · 95% clinician	no trial data cached
Product storage error	175	9.1 7.9–10.6ROR 9.5 · χ² 1,262 / p 9e-277	9.0 EB05 7.9 · IC025 +2.9 3/3 methods agree	Reporting / coding artifact	serious PRR 3.0 · 94% clinician	no trial data cached
Lymphopenia	25	8.0 5.4–11.9ROR 8.1 · χ² 147 / p 5e-34	7.2 EB05 5.1 · IC025 +2.1 3/3 methods agree	Not in label — unassessed	serious PRR 6.3 · 100% clinician	no trial data cached
Proteinuria	32	7.7 5.4–10.8ROR 7.7 · χ² 179 / p 5e-41	7.0 EB05 5.2 · IC025 +2.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.9	no trial data cached
Leukopenia (low white blood cells)	82	7.4 6.0–9.2ROR 7.5 · χ² 449 / p 5e-100	7.2 EB05 5.9 · IC025 +2.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.8 · 91% clinician	no trial data cached
Acute respiratory distress syndrome	27	6.9 4.7–10.0ROR 6.9 · χ² 130 / p 2e-30	6.2 EB05 4.5 · IC025 +2.0 3/3 methods agree	Labeled (related wording) related wording	serious PRR 5.2 · ♀ 12% (drug 41%) · 93% clinician	no trial data cached
Cardiogenic shock	21	6.6 4.3–10.2ROR 6.7 · χ² 95 / p 9e-23	5.9 EB05 4.0 · IC025 +1.8 3/3 methods agree	Not in label — unassessed	serious PRR 5.0 · ♀ 19% (drug 41%)	no trial data cached
Squamous cell carcinoma	13	6.2 3.6–10.7ROR 6.2 · χ² 52 / p 3e-13	5.2 EB05 3.2 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 4.9	no trial data cached
Septic shock	55	5.7 4.4–7.5ROR 5.8 · χ² 211 / p 4e-48	5.5 EB05 4.4 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 4.3	no trial data cached
Covid-19 pneumonia	15	5.7 3.4–9.4ROR 5.7 · χ² 53 / p 1e-13	4.9 EB05 3.2 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 4.4	no trial data cached
Cytopenia	15	5.7 3.4–9.4ROR 5.7 · χ² 53 / p 2e-13	4.9 EB05 3.1 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 4.4	no trial data cached
Multiple organ dysfunction syndrome	35	5.7 4.1–7.9ROR 5.7 · χ² 130 / p 2e-30	5.3 EB05 4.0 · IC025 +1.8 3/3 methods agree	Not in label — unassessed	serious PRR 4.3 · 94% clinician	no trial data cached
Acute respiratory failure	23	5.4 3.6–8.2ROR 5.4 · χ² 79 / p 4e-19	4.9 EB05 3.5 · IC025 +1.6 3/3 methods agree	Labeled (related wording) related wording	serious PRR 4.1 · 100% clinician	no trial data cached
Acute kidney injury (sudden kidney damage)	178	5.3 4.6–6.1ROR 5.4 · χ² 616 / p 3e-136	5.2 EB05 4.6 · IC025 +2.1 3/3 methods agree	Labeled (related wording) related wording	serious PRR 4.0 · 93% clinician	no trial data cached
Tuberculosis	15	5.3 3.2–8.7ROR 5.3 · χ² 48 / p 3e-12	4.6 EB05 3.0 · IC025 +1.3 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.1	no trial data cached
Prescribed underdose	23	5.2 3.5–7.8ROR 5.2 · χ² 74 / p 4e-18	4.7 EB05 3.3 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 4.4	no trial data cached
Oral candidiasis (oral thrush)	15	5.2 3.1–8.6ROR 5.2 · χ² 47 / p 4e-12	4.5 EB05 2.9 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 5.1	no trial data cached
Dialysis	16	5.1 3.1–8.3ROR 5.1 · χ² 48 / p 2e-12	4.5 EB05 2.9 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 4.0	no trial data cached
Blood creatinine increased	73	5.0 4.0–6.3ROR 5.1 · χ² 233 / p 8e-53	4.9 EB05 4.0 · IC025 +1.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.0	no trial data cached
Basal cell carcinoma	17	4.9 3.1–7.9ROR 4.9 · χ² 49 / p 1e-12	4.4 EB05 2.9 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 3.6	no trial data cached
Multi-organ failure	19	4.9 3.1–7.7ROR 4.9 · χ² 55 / p 6e-14	4.4 EB05 3.0 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 3.7	no trial data cached
Pulmonary mass	16	4.9 3.0–7.9ROR 4.9 · χ² 45 / p 9e-12	4.3 EB05 2.8 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 4.0	no trial data cached
Intercepted product preparation error	13	4.8 2.8–8.3ROR 4.8 · χ² 36 / p 1e-9	4.2 EB05 2.6 · IC025 +1.1 3/3 methods agree	Not in label — unassessed	–	no trial data cached
Respiratory failure	77	4.8 3.8–5.9ROR 4.8 · χ² 226 / p 3e-51	4.6 EB05 3.8 · IC025 +1.8 3/3 methods agree	Labeled (related wording) related wording	serious PRR 3.6 · 95% clinician	no trial data cached
Atelectasis	10	4.7 2.5–8.6ROR 4.7 · χ² 25 / p 3e-7	3.9 EB05 2.3 · IC025 +0.9 3/3 methods agree	Not in label — unassessed	serious PRR 3.6	no trial data cached
Sudden death	11	4.6 2.6–8.4ROR 4.7 · χ² 28 / p 6e-8	4.0 EB05 2.4 · IC025 +1.0 3/3 methods agree	Outcome field, not a reaction boxed warning mentions mortality	serious PRR 3.5	no trial data cached
Tubulointerstitial nephritis	19	4.6 2.9–7.2ROR 4.6 · χ² 50 / p 9e-13	4.2 EB05 2.8 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 3.5	no trial data cached
Mouth ulceration	21	4.5 2.9–6.9ROR 4.5 · χ² 54 / p 1e-13	4.1 EB05 2.9 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 0.9 · 95% clinician	no trial data cached
Intentional product use issue	86	4.4 3.6–5.4ROR 4.5 · χ² 224 / p 5e-51	4.3 EB05 3.6 · IC025 +1.8 3/3 methods agree	Reporting / coding artifact	serious PRR 2.9	no trial data cached
Myocarditis	11	4.4 2.4–7.9ROR 4.4 · χ² 25 / p 2e-7	3.8 EB05 2.3 · IC025 +0.9 3/3 methods agree	Not in label — unassessed	serious PRR 3.3	no trial data cached

Trial evidence (ClinicalTrials.gov)

Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).

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
Off label use (used outside approved label)	451	2.3 2.1–2.6ROR 2.5 · χ² 361 / p 9e-81	2.3 EB05 2.2 · IC025 +1.1 3/3 methods agree	Reporting / coding artifact	serious PRR 2.5	no trial data cached
Death	232	1.2 1.1–1.4ROR 1.2 · χ² 9 / p 0.001	1.2 EB05 1.1 · IC025 +0.1	Outcome field, not a reaction boxed warning mentions mortality	serious PRR 0.9	no trial data cached
Cytomegalovirus infection	180	49.3 42.7–57.0ROR 51.3 · χ² 8,386 / p <1e-300	48.5 EB05 42.9 · IC025 +5.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 36.3 · 93% clinician	no trial data cached
Acute kidney injury (sudden kidney damage)	178	5.3 4.6–6.1ROR 5.4 · χ² 616 / p 3e-136	5.2 EB05 4.6 · IC025 +2.1 3/3 methods agree	Labeled (related wording) related wording	serious PRR 4.0 · 93% clinician	no trial data cached
Product storage error	175	9.1 7.9–10.6ROR 9.5 · χ² 1,262 / p 9e-277	9.0 EB05 7.9 · IC025 +2.9 3/3 methods agree	Reporting / coding artifact	serious PRR 3.0 · 94% clinician	no trial data cached
Covid-19	149	3.8 3.2–4.4ROR 3.9 · χ² 307 / p 5e-69	3.8 EB05 3.3 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 4.6	no trial data cached
Hospitalisation	126	3.7 3.1–4.4ROR 3.8 · χ² 251 / p 9e-57	3.7 EB05 3.2 · IC025 +1.6 3/3 methods agree	Reporting / coding artifact	serious PRR 2.9	no trial data cached
Thrombotic microangiopathy	104	48.9 40.4–59.2ROR 50.0 · χ² 4,784 / p <1e-300	48.0 EB05 40.7 · IC025 +5.0 3/3 methods agree	Not in label — unassessed	serious PRR 36.3 · 96% clinician	no trial data cached
Urinary tract infection (bladder infection)	94	2.5 2.0–3.0ROR 2.5 · χ² 83 / p 4e-20	2.5 EB05 2.1 · IC025 +1.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 2.2 · ♀ 63% (drug 41%)	no trial data cached
Sepsis (blood infection)	92	3.7 3.0–4.6ROR 3.8 · χ² 181 / p 1e-41	3.7 EB05 3.1 · IC025 +1.5 3/3 methods agree	Labeled — boxed warning synonym match	serious PRR 2.8	no trial data cached
Intentional product use issue	86	4.4 3.6–5.4ROR 4.5 · χ² 224 / p 5e-51	4.3 EB05 3.6 · IC025 +1.8 3/3 methods agree	Reporting / coding artifact	serious PRR 2.9	no trial data cached
Product preparation error	86	18.8 15.2–23.2ROR 19.1 · χ² 1,427 / p <1e-300	18.6 EB05 15.6 · IC025 +3.7 3/3 methods agree	Reporting / coding artifact	95% clinician	no trial data cached
Pneumocystis jirovecii pneumonia	85	38.7 31.3–47.8ROR 39.4 · χ² 3,056 / p <1e-300	38.0 EB05 31.7 · IC025 +4.6 3/3 methods agree	Not in label — unassessed	serious PRR 29.1 · 93% clinician	no trial data cached
Leukopenia (low white blood cells)	82	7.4 6.0–9.2ROR 7.5 · χ² 449 / p 5e-100	7.2 EB05 5.9 · IC025 +2.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.8 · 91% clinician	no trial data cached
Respiratory failure	77	4.8 3.8–5.9ROR 4.8 · χ² 226 / p 3e-51	4.6 EB05 3.8 · IC025 +1.8 3/3 methods agree	Labeled (related wording) related wording	serious PRR 3.6 · 95% clinician	no trial data cached

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.

Thrombotic microangiopathy — n=104, PRR 48.9
Pneumocystis jirovecii pneumonia — n=85, PRR 38.7
Posterior reversible encephalopathy syndrome — n=30, PRR 14.3
Urosepsis — n=24, PRR 11.8
Bacteraemia — n=28, PRR 10.7
Clostridium difficile colitis — n=22, PRR 9.4
Lymphopenia — n=25, PRR 8.0
Cardiogenic shock — n=21, PRR 6.6
Septic shock — n=55, PRR 5.7
Multiple organ dysfunction syndrome — n=35, PRR 5.7

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 Belatacept?

In FDA FAERS, the most frequently co-reported reaction terms for Belatacept are cytomegalovirus infection, acute kidney injury, covid-19, thrombotic microangiopathy, urinary tract infection, sepsis. 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 Belatacept have an FDA boxed warning?

Yes. The current FDA label carries a boxed warning: POST-TRANSPLANT LYMPHOPROLIFERATIVE DISORDER, OTHER MALIGNANCIES, AND SERIOUS INFECTIONS Increased risk for developing post-transplant lymphoproliferative disorder (PTLD), predominantly involving the central nervous system (CNS).

Do FAERS signals prove that Belatacept 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 c16ac648-d5d2-9f7d-8637-e2328572754e, effective 20210728; matched on openfda.generic_name.exact:"BELATACEPT")
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, 118 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

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.