Ibritumomab Tiuxetan side effects: what 1,521 FDA adverse event reports show
Drug class
Not stated in label
Brand names
Zevalin
Who reports
1,521 reports · 93% serious · 551 with death outcome · 41% female
Used for
Zevalin is a CD20-directed radiotherapeutic antibody administered as part of the Zevalin therapeutic regimen indicated for the treatment of adult patients with: relapsed or refractory, low-grade or follicular B-cell non-Hodgkin's lymphoma (NHL) ( 1.1 ). previously untreated follicular NHL who achieve a partial or complete response to first-line chemotherapy ( 1.2 ).
What it is
Zevalin (ibritumomab tiuxetan) is the immunoconjugate resulting from a stable thiourea covalent bond between the monoclonal antibody ibritumomab and the linker-chelator tiuxetan [N-[2-bis(carboxymethyl) amino]-3-(p-isothiocyanatophenyl)-propyl]-[N-[2-bis(carboxymethyl)amino]-2- (methyl)-ethyl]glycine.
Boxed warning
SERIOUS INFUSION REACTIONS, PROLONGED AND SEVERE CYTOPENIAS, and SEVERE CUTANEOUS AND MUCOCUTANEOUS REACTIONS Serious Infusion Reactions: Deaths have occurred within 24 hours of rituximab infusion, an essential component of the Zevalin therapeutic regimen.
Causality screen of the 39 strongest signals
What the badges mean
- Labeled — boxed warning The term (or its clinical synonym) appears in the FDA boxed warning: causality is regulator-recognised and considered serious.
- 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.
- 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. 25 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Myelodysplastic syndrome | 98 | 94.0 77.5–113.9ROR 100.4 · χ² 8,867 / p <1e-300 | 91.7 EB05 77.5 · IC025 +5.7 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 58.3 | no trial data cached |
| Acute myeloid leukaemia | 55 | 48.9 37.7–63.4ROR 50.7 · χ² 2,524 / p <1e-300 | 47.9 EB05 38.2 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious PRR 30.3 | no trial data cached |
| Bone marrow failure | 65 | 43.9 34.6–55.8ROR 45.9 · χ² 2,678 / p <1e-300 | 43.3 EB05 35.1 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious PRR 27.2 · 95% clinician | no trial data cached |
| Mucosal inflammation | 72 | 38.2 30.5–47.9ROR 40.0 · χ² 2,566 / p <1e-300 | 37.7 EB05 31.0 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious PRR 25.1 | no trial data cached |
| Cytomegalovirus infection | 35 | 29.1 20.9–40.3ROR 29.7 · χ² 919 / p 3e-202 | 28.6 EB05 21.5 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious PRR 18.2 · 100% clinician | no trial data cached |
| Multi-organ failure | 35 | 27.6 19.9–38.2ROR 28.2 · χ² 868 / p 4e-191 | 27.1 EB05 20.4 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious PRR 17.0 · 93% clinician | no trial data cached |
| Thrombocytopenia (low platelets) | 174 | 21.5 18.7–24.8ROR 24.2 · χ² 3,401 / p <1e-300 | 21.5 EB05 18.9 · IC025 +4.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 12.6 · 91% clinician | no trial data cached |
| Sepsis (blood infection) | 172 | 21.3 18.5–24.5ROR 23.9 · χ² 3,316 / p <1e-300 | 21.2 EB05 18.7 · IC025 +4.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 13.2 | no trial data cached |
| Febrile neutropenia | 94 | 19.6 16.1–23.8ROR 20.8 · χ² 1,643 / p <1e-300 | 19.5 EB05 16.4 · IC025 +3.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 12.1 · 91% clinician | no trial data cached |
| Haematotoxicity | 13 | 19.4 11.3–33.3ROR 19.5 · χ² 208 / p 2e-47 | 18.5 EB05 11.0 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 12.3 | no trial data cached |
| Pancytopenia (all blood cells low) | 78 | 19.3 15.6–24.0ROR 20.3 · χ² 1,338 / p 2e-293 | 19.2 EB05 15.9 · IC025 +3.7 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 10.9 | no trial data cached |
| Clostridium difficile colitis | 14 | 18.2 10.8–30.7ROR 18.4 · χ² 210 / p 5e-48 | 17.4 EB05 10.5 · IC025 +2.6 3/3 methods agree | Labeled (related wording) related wording | serious PRR 11.5 | no trial data cached |
| Drug toxicity | 16 | 16.0 9.8–26.0ROR 16.1 · χ² 210 / p 7e-48 | 15.3 EB05 9.4 · IC025 +2.6 3/3 methods agree | Labeled (related wording) related wording | serious PRR 10.3 | no trial data cached |
| Lymphoma | 17 | 15.1 9.4–24.3ROR 15.3 · χ² 210 / p 5e-48 | 14.4 EB05 9.0 · IC025 +2.6 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 9.5 | no trial data cached |
| Neutropenia (low neutrophils (infection-fighting cells)) | 141 | 14.4 12.3–16.8ROR 15.7 · χ² 1,749 / p <1e-300 | 14.3 EB05 12.4 · IC025 +3.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 8.9 · 92% clinician | no trial data cached |
| Respiratory disorder | 30 | 13.8 9.7–19.7ROR 14.1 · χ² 344 / p 5e-77 | 13.4 EB05 9.6 · IC025 +2.9 3/3 methods agree | Labeled (related wording) related wording | serious PRR 10.6 · ♀ 0% (drug 41%) | no trial data cached |
| Neutrophil count decreased | 40 | 13.6 10.0–18.5ROR 14.0 · χ² 456 / p 2e-101 | 13.3 EB05 10.1 · IC025 +3.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 9.5 | no trial data cached |
| Mitral valve incompetence | 10 | 12.2 6.6–22.6ROR 12.3 · χ² 92 / p 5e-22 | 10.1 EB05 5.2 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 7.6 | no trial data cached |
| Leukopenia (low white blood cells) | 44 | 12.2 9.1–16.3ROR 12.5 · χ² 441 / p 4e-98 | 11.8 EB05 9.0 · IC025 +2.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 7.6 | no trial data cached |
| Blood lactate dehydrogenase increased | 14 | 12.1 7.2–20.4ROR 12.2 · χ² 132 / p 8e-31 | 10.8 EB05 6.2 · IC025 +2.2 3/3 methods agree | Lab value / disease marker | serious PRR 8.0 | no trial data cached |
| Respiratory failure | 62 | 11.7 9.2–15.0ROR 12.2 · χ² 599 / p 1e-132 | 11.5 EB05 9.2 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious PRR 7.3 · ♀ 18% (drug 41%) | no trial data cached |
| Septic shock | 35 | 11.2 8.1–15.5ROR 11.4 · χ² 314 / p 1e-70 | 10.7 EB05 7.8 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 6.9 · 97% clinician | no trial data cached |
| Platelet count decreased | 84 | 10.9 8.8–13.4ROR 11.5 · χ² 747 / p 9e-165 | 10.7 EB05 8.8 · IC025 +3.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 8.1 | no trial data cached |
| White blood cell count decreased | 83 | 10.6 8.6–13.0ROR 11.1 · χ² 711 / p 5e-157 | 10.3 EB05 8.5 · IC025 +3.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 8.9 | no trial data cached |
| Staphylococcal infection | 25 | 10.4 7.1–15.4ROR 10.6 · χ² 204 / p 2e-46 | 9.6 EB05 6.6 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious PRR 7.1 · ♀ 20% (drug 41%) · 92% clinician | no trial data cached |
| Disease progression | 85 | 9.9 8.1–12.2ROR 10.5 · χ² 678 / p 8e-150 | 9.7 EB05 8.0 · IC025 +2.9 3/3 methods agree | Reporting / coding artifact | serious PRR 4.9 · 90% clinician | no trial data cached |
| Haematocrit decreased | 14 | 9.7 5.7–16.3ROR 9.8 · χ² 100 / p 6e-24 | 8.2 EB05 4.9 · IC025 +2.0 3/3 methods agree | Lab value / disease marker | serious PRR 6.3 | no trial data cached |
| Acute respiratory distress syndrome | 12 | 9.4 5.3–16.4ROR 9.4 · χ² 81 / p 9e-20 | 7.6 EB05 4.4 · IC025 +1.8 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 5.8 | no trial data cached |
| Toxic epidermal necrolysis (severe skin peeling reaction) | 10 | 9.1 4.9–17.0ROR 9.2 · χ² 65 / p 4e-16 | 7.2 EB05 3.9 · IC025 +1.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.7 | no trial data cached |
| Hepatic failure | 19 | 8.7 5.5–13.6ROR 8.8 · χ² 121 / p 1e-28 | 7.6 EB05 5.0 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 5.4 | no trial data cached |
| Cholestasis (bile flow blockage) | 11 | 7.9 4.4–14.3ROR 8.0 · χ² 60 / p 5e-15 | 6.3 EB05 3.7 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 5.0 | no trial data cached |
| Lymphocyte count decreased | 10 | 7.8 4.2–14.5ROR 7.8 · χ² 53 / p 2e-13 | 6.1 EB05 3.4 · IC025 +1.5 3/3 methods agree | Lab value / disease marker | serious PRR 5.9 | no trial data cached |
| Lymphadenopathy | 17 | 6.6 4.1–10.6ROR 6.7 · χ² 76 / p 2e-18 | 5.7 EB05 3.8 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 4.7 | no trial data cached |
| Stevens-johnson syndrome (severe blistering skin reaction) | 10 | 6.2 3.3–11.5ROR 6.2 · χ² 38 / p 3e-10 | 5.0 EB05 2.9 · IC025 +1.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.9 | no trial data cached |
| Renal failure acute | 19 | 6.1 3.9–9.5ROR 6.2 · χ² 76 / p 1e-18 | 5.4 EB05 3.6 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 3.8 | no trial data cached |
| Disease recurrence | 19 | 5.5 3.5–8.6ROR 5.5 · χ² 65 / p 3e-16 | 4.9 EB05 3.3 · IC025 +1.5 3/3 methods agree | Reporting / coding artifact | serious PRR 6.7 | no trial data cached |
| Malignant neoplasm progression | 36 | 4.9 3.5–6.7ROR 5.0 · χ² 107 / p 2e-25 | 4.6 EB05 3.5 · IC025 +1.7 3/3 methods agree | Reporting / coding artifact | serious PRR 3.1 · 91% clinician | no trial data cached |
| Myelosuppression | 11 | 4.5 2.5–8.0ROR 4.5 · χ² 26 / p 2e-7 | 3.8 EB05 2.3 · IC025 +0.9 3/3 methods agree | Not in label — unassessed | serious PRR 2.8 | no trial data cached |
| Lung neoplasm malignant | 11 | 3.7 2.0–6.6ROR 3.7 · χ² 19 / p 7e-6 | 3.3 EB05 2.0 · IC025 +0.7 | Not in label — unassessed | serious PRR 2.3 | no trial data cached |
Trial evidence (ClinicalTrials.gov)
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 |
|---|---|---|---|---|---|---|
| Thrombocytopenia (low platelets) | 174 | 21.5 18.7–24.8ROR 24.2 · χ² 3,401 / p <1e-300 | 21.5 EB05 18.9 · IC025 +4.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 12.6 · 91% clinician | no trial data cached |
| Sepsis (blood infection) | 172 | 21.3 18.5–24.5ROR 23.9 · χ² 3,316 / p <1e-300 | 21.2 EB05 18.7 · IC025 +4.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 13.2 | no trial data cached |
| Neutropenia (low neutrophils (infection-fighting cells)) | 141 | 14.4 12.3–16.8ROR 15.7 · χ² 1,749 / p <1e-300 | 14.3 EB05 12.4 · IC025 +3.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 8.9 · 92% clinician | no trial data cached |
| Myelodysplastic syndrome | 98 | 94.0 77.5–113.9ROR 100.4 · χ² 8,867 / p <1e-300 | 91.7 EB05 77.5 · IC025 +5.7 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 58.3 | no trial data cached |
| Febrile neutropenia | 94 | 19.6 16.1–23.8ROR 20.8 · χ² 1,643 / p <1e-300 | 19.5 EB05 16.4 · IC025 +3.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 12.1 · 91% clinician | no trial data cached |
| Disease progression | 85 | 9.9 8.1–12.2ROR 10.5 · χ² 678 / p 8e-150 | 9.7 EB05 8.0 · IC025 +2.9 3/3 methods agree | Reporting / coding artifact | serious PRR 4.9 · 90% clinician | no trial data cached |
| Platelet count decreased | 84 | 10.9 8.8–13.4ROR 11.5 · χ² 747 / p 9e-165 | 10.7 EB05 8.8 · IC025 +3.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 8.1 | no trial data cached |
| White blood cell count decreased | 83 | 10.6 8.6–13.0ROR 11.1 · χ² 711 / p 5e-157 | 10.3 EB05 8.5 · IC025 +3.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 8.9 | no trial data cached |
| Pancytopenia (all blood cells low) | 78 | 19.3 15.6–24.0ROR 20.3 · χ² 1,338 / p 2e-293 | 19.2 EB05 15.9 · IC025 +3.7 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 10.9 | no trial data cached |
| Mucosal inflammation | 72 | 38.2 30.5–47.9ROR 40.0 · χ² 2,566 / p <1e-300 | 37.7 EB05 31.0 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious PRR 25.1 | no trial data cached |
| Bone marrow failure | 65 | 43.9 34.6–55.8ROR 45.9 · χ² 2,678 / p <1e-300 | 43.3 EB05 35.1 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious PRR 27.2 · 95% clinician | no trial data cached |
| Respiratory failure | 62 | 11.7 9.2–15.0ROR 12.2 · χ² 599 / p 1e-132 | 11.5 EB05 9.2 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious PRR 7.3 · ♀ 18% (drug 41%) | no trial data cached |
| Acute myeloid leukaemia | 55 | 48.9 37.7–63.4ROR 50.7 · χ² 2,524 / p <1e-300 | 47.9 EB05 38.2 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious PRR 30.3 | no trial data cached |
| Leukopenia (low white blood cells) | 44 | 12.2 9.1–16.3ROR 12.5 · χ² 441 / p 4e-98 | 11.8 EB05 9.0 · IC025 +2.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 7.6 | no trial data cached |
| Neutrophil count decreased | 40 | 13.6 10.0–18.5ROR 14.0 · χ² 456 / p 2e-101 | 13.3 EB05 10.1 · IC025 +3.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 9.5 | 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.
- Acute myeloid leukaemia — n=55, PRR 48.9
- Bone marrow failure — n=65, PRR 43.9
- Mucosal inflammation — n=72, PRR 38.2
- Cytomegalovirus infection — n=35, PRR 29.1
- Multi-organ failure — n=35, PRR 27.6
- Respiratory failure — n=62, PRR 11.7
- Septic shock — n=35, PRR 11.2
- Staphylococcal infection — n=25, PRR 10.4
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 Ibritumomab Tiuxetan?
In FDA FAERS, the most frequently co-reported reaction terms for Ibritumomab Tiuxetan are thrombocytopenia, sepsis, neutropenia, myelodysplastic syndrome, febrile neutropenia, platelet count decreased. 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 Ibritumomab Tiuxetan have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: SERIOUS INFUSION REACTIONS, PROLONGED AND SEVERE CYTOPENIAS, and SEVERE CUTANEOUS AND MUCOCUTANEOUS REACTIONS Serious Infusion Reactions: Deaths have occurred within 24 hours of rituximab infusion, an essential component of the Zevalin therapeutic regimen.
Do FAERS signals prove that Ibritumomab Tiuxetan 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 25d367dc-da65-44c9-a844-1bf15339c285, effective 20230425; matched on
openfda.generic_name.exact:"IBRITUMOMAB TIUXETAN") - 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, fieldpatient.drug.openfda.generic_name.exact, 64 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.