Inotuzumab Ozogamicin side effects: what 2,937 FDA adverse event reports show

Inotuzumab Ozogamicin · Besponsa · 97 reaction terms · 3,520 drug–reaction co-reports · data 2026-09-14

Drug class

CD22-directed Immunoconjugate

FDA label (Established Pharmacologic Class)

Brand names

Besponsa

openFDA label

Who reports

2,937 reports · 95% serious · 996 with death outcome · 42% female

openFDA FAERS counts, all years, deduplication not applied

Used for

1. INDICATIONS AND USAGE BESPONSA is indicated for the treatment of relapsed or refractory CD22-positive B-cell precursor acute lymphoblastic leukemia (ALL) in adult and pediatric patients 1 year and older . BESPONSA is a CD22-directed antibody and cyt.

FDA label, Indications and Usage

What it is

11. DESCRIPTION Inotuzumab ozogamicin is a CD22-directed antibody and cytotoxic-drug conjugate (ADC) consisting of 3 components: 1) the recombinant humanized immunoglobulin class G subtype 4 (.

FDA label, Description section

Boxed warning

HEPATOTOXICITY, INCLUDING HEPATIC VENO-OCCLUSIVE DISEASE (VOD) (ALSO KNOWN AS SINUSOIDAL OBSTRUCTION SYNDROME) and INCREASED RISK OF POST-HEMATOPOIETIC STEM CELL TRANSPLANT (HSCT) NON-RELAPSE MORTALITY WARNING: HEPAT.

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 — boxed warning 2Labeled adverse reaction 23Labeled (related wording) 2Lab value / disease marker 1Not in label — unassessed 12

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.
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. 57 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
Cytokine release syndrome	133	50.2 42.5–59.3ROR 52.5 · χ² 6,322 / p <1e-300	49.5 EB05 42.8 · IC025 +5.1 3/3 methods agree	Not in label — unassessed	serious PRR 30.4 · 98% clinician	no trial data cached
Cytopenia	57	34.2 26.4–44.3ROR 34.9 · χ² 1,797 / p <1e-300	33.7 EB05 27.0 · IC025 +4.3 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 20.5 · 96% clinician	no trial data cached
Neoplasm progression	155	31.7 27.2–36.9ROR 33.4 · χ² 4,559 / p <1e-300	31.4 EB05 27.5 · IC025 +4.6 3/3 methods agree	Not in label — unassessed	serious PRR 20.9	no trial data cached
Febrile neutropenia	265	28.7 25.6–32.2ROR 31.4 · χ² 7,046 / p <1e-300	28.5 EB05 25.8 · IC025 +4.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 17.3 · 95% clinician	no trial data cached
Thrombotic microangiopathy	31	22.9 16.1–32.5ROR 23.2 · χ² 626 / p 2e-138	22.6 EB05 16.6 · IC025 +3.5 3/3 methods agree	Not in label — unassessed	serious PRR 13.8 · 100% clinician	no trial data cached
Neurotoxicity	55	22.7 17.4–29.5ROR 23.1 · χ² 1,115 / p 1e-244	22.4 EB05 17.9 · IC025 +3.8 3/3 methods agree	Not in label — unassessed	serious PRR 13.8 · ♀ 72% (drug 42%) · 96% clinician	no trial data cached
Blood bilirubin increased	82	21.7 17.5–26.8ROR 22.3 · χ² 1,594 / p <1e-300	21.5 EB05 17.9 · IC025 +3.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 14.3 · 91% clinician	no trial data cached
Hyperbilirubinaemia	30	20.8 14.6–29.8ROR 21.1 · χ² 546 / p 5e-121	20.5 EB05 15.0 · IC025 +3.4 3/3 methods agree	Not in label — unassessed	serious PRR 12.8	no trial data cached
Multiple organ dysfunction syndrome	81	20.8 16.8–25.8ROR 21.3 · χ² 1,503 / p <1e-300	20.6 EB05 17.1 · IC025 +3.8 3/3 methods agree	Not in label — unassessed	serious PRR 12.3 · 95% clinician	no trial data cached
Subdural haematoma	31	15.4 10.9–21.9ROR 15.6 · χ² 404 / p 4e-90	15.1 EB05 11.0 · IC025 +3.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 9.3 · 100% clinician	no trial data cached
Hepatotoxicity (liver damage)	47	15.2 11.4–20.1ROR 15.4 · χ² 607 / p 2e-134	15.0 EB05 11.6 · IC025 +3.2 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 9.3 · ♀ 19% (drug 42%) · 94% clinician	no trial data cached
Ascites	62	15.1 11.8–19.3ROR 15.4 · χ² 800 / p 2e-176	14.9 EB05 12.0 · IC025 +3.3 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 9.1	no trial data cached
Bacteraemia	23	14.0 9.3–21.0ROR 14.1 · χ² 264 / p 1e-59	13.4 EB05 9.0 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.5 · 100% clinician	no trial data cached
Lymphocyte count decreased	34	13.7 9.8–19.2ROR 13.9 · χ² 389 / p 7e-87	13.4 EB05 9.8 · IC025 +3.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 10.2 · 97% clinician	no trial data cached
Mucosal inflammation	47	12.9 9.7–17.1ROR 13.1 · χ² 504 / p 8e-112	12.6 EB05 9.7 · IC025 +3.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.3 · 96% clinician	no trial data cached
Hepatomegaly	17	12.3 7.7–19.8ROR 12.4 · χ² 165 / p 4e-38	11.3 EB05 6.9 · IC025 +2.4 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.1	no trial data cached
Encephalopathy	38	11.1 8.1–15.2ROR 11.2 · χ² 339 / p 6e-76	10.6 EB05 7.9 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 6.7 · 92% clinician	no trial data cached
Myelosuppression	50	10.5 8.0–13.8ROR 10.7 · χ² 421 / p 9e-94	10.1 EB05 7.9 · IC025 +2.8 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 6.3 · 92% clinician	no trial data cached
Bone marrow failure	29	10.1 7.1–14.6ROR 10.2 · χ² 230 / p 4e-52	9.4 EB05 6.7 · IC025 +2.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.9 · 100% clinician	no trial data cached
Haematotoxicity	13	10.0 5.8–17.2ROR 10.1 · χ² 97 / p 4e-23	8.4 EB05 4.9 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 6.2	no trial data cached
Neutrophil count decreased	55	9.7 7.5–12.6ROR 9.9 · χ² 421 / p 7e-94	9.3 EB05 7.3 · IC025 +2.7 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 6.7 · 98% clinician	no trial data cached
Thrombocytopenia (low platelets)	148	9.5 8.1–11.1ROR 9.9 · χ² 1,120 / p 9e-246	9.3 EB05 8.1 · IC025 +2.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.9 · 93% clinician	no trial data cached
Blood lactate dehydrogenase increased	20	9.0 5.8–13.9ROR 9.0 · χ² 134 / p 3e-31	7.9 EB05 5.2 · IC025 +2.2 3/3 methods agree	Lab value / disease marker	serious PRR 5.5	no trial data cached
Liver function test increased	26	8.7 5.9–12.8ROR 8.8 · χ² 170 / p 4e-39	7.9 EB05 5.5 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 8.2	no trial data cached
Sepsis (blood infection)	136	8.7 7.4–10.3ROR 9.1 · χ² 924 / p 3e-203	8.5 EB05 7.4 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.2 · 96% clinician	no trial data cached
Hyperglycaemia (high blood sugar)	44	8.7 6.5–11.6ROR 8.8 · χ² 291 / p 2e-65	8.2 EB05 6.3 · IC025 +2.5 3/3 methods agree	Not in label — unassessed	serious PRR 5.9 · 91% clinician	no trial data cached
Lymphopenia	16	8.1 5.0–13.3ROR 8.2 · χ² 93 / p 3e-22	6.9 EB05 4.4 · IC025 +1.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.0	no trial data cached
Platelet count decreased	121	8.1 6.8–9.7ROR 8.4 · χ² 751 / p 1e-165	7.9 EB05 6.8 · IC025 +2.7 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.9	no trial data cached
Acute hepatic failure	15	7.9 4.8–13.1ROR 7.9 · χ² 83 / p 3e-20	6.6 EB05 4.2 · IC025 +1.8 3/3 methods agree	Labeled (related wording) related wording	serious PRR 4.8	no trial data cached
Hepatic failure	33	7.8 5.6–11.0ROR 7.9 · χ² 189 / p 3e-43	7.2 EB05 5.3 · IC025 +2.2 3/3 methods agree	Labeled (related wording) related wording	serious PRR 4.7 · 91% clinician	no trial data cached
Aspartate aminotransferase increased	57	7.7 5.9–9.9ROR 7.8 · χ² 325 / p 7e-73	7.3 EB05 5.8 · IC025 +2.4 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.8	no trial data cached
Cytomegalovirus infection	17	7.3 4.5–11.7ROR 7.3 · χ² 86 / p 8e-21	6.3 EB05 4.1 · IC025 +1.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.5	no trial data cached
Covid-19 pneumonia	12	7.2 4.1–12.7ROR 7.2 · χ² 58 / p 1e-14	5.9 EB05 3.5 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 4.4	no trial data cached
Transaminases increased	22	7.1 4.7–10.7ROR 7.1 · χ² 109 / p 9e-26	6.3 EB05 4.3 · IC025 +1.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.6	no trial data cached
Myelodysplastic syndrome	14	6.9 4.1–11.7ROR 6.9 · χ² 65 / p 4e-16	5.8 EB05 3.6 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 4.2	no trial data cached
Hyponatraemia (low sodium)	54	6.9 5.3–8.9ROR 7.0 · χ² 265 / p 6e-60	6.5 EB05 5.2 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 4.2	no trial data cached
Pancytopenia (all blood cells low)	53	6.8 5.2–8.9ROR 6.9 · χ² 257 / p 5e-58	6.5 EB05 5.1 · IC025 +2.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.1 · 96% clinician	no trial data cached
Septic shock	39	6.4 4.7–8.8ROR 6.5 · χ² 174 / p 4e-40	6.0 EB05 4.6 · IC025 +2.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 3.8	no trial data cached
Alanine aminotransferase increased	54	6.3 4.8–8.2ROR 6.4 · χ² 235 / p 2e-53	6.0 EB05 4.8 · IC025 +2.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.0	no trial data cached
Neutropenia (low neutrophils (infection-fighting cells))	118	6.2 5.2–7.4ROR 6.4 · χ² 515 / p 3e-114	6.1 EB05 5.2 · IC025 +2.3 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 3.9 · 97% clinician	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
Death	343	2.8 2.6–3.1ROR 3.1 · χ² 426 / p 7e-95	2.8 EB05 2.6 · IC025 +1.3 3/3 methods agree	Outcome field, not a reaction boxed warning mentions mortality	serious PRR 1.7	no trial data cached
Febrile neutropenia	265	28.7 25.6–32.2ROR 31.4 · χ² 7,046 / p <1e-300	28.5 EB05 25.8 · IC025 +4.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 17.3 · 95% clinician	no trial data cached
Neoplasm progression	155	31.7 27.2–36.9ROR 33.4 · χ² 4,559 / p <1e-300	31.4 EB05 27.5 · IC025 +4.6 3/3 methods agree	Not in label — unassessed	serious PRR 20.9	no trial data cached
Thrombocytopenia (low platelets)	148	9.5 8.1–11.1ROR 9.9 · χ² 1,120 / p 9e-246	9.3 EB05 8.1 · IC025 +2.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.9 · 93% clinician	no trial data cached
Sepsis (blood infection)	136	8.7 7.4–10.3ROR 9.1 · χ² 924 / p 3e-203	8.5 EB05 7.4 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.2 · 96% clinician	no trial data cached
Cytokine release syndrome	133	50.2 42.5–59.3ROR 52.5 · χ² 6,322 / p <1e-300	49.5 EB05 42.8 · IC025 +5.1 3/3 methods agree	Not in label — unassessed	serious PRR 30.4 · 98% clinician	no trial data cached
Platelet count decreased	121	8.1 6.8–9.7ROR 8.4 · χ² 751 / p 1e-165	7.9 EB05 6.8 · IC025 +2.7 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.9	no trial data cached
Neutropenia (low neutrophils (infection-fighting cells))	118	6.2 5.2–7.4ROR 6.4 · χ² 515 / p 3e-114	6.1 EB05 5.2 · IC025 +2.3 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 3.9 · 97% clinician	no trial data cached
Infection	93	4.6 3.8–5.6ROR 4.7 · χ² 261 / p 6e-59	4.5 EB05 3.8 · IC025 +1.8 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 3.5 · 90% clinician	no trial data cached
Blood bilirubin increased	82	21.7 17.5–26.8ROR 22.3 · χ² 1,594 / p <1e-300	21.5 EB05 17.9 · IC025 +3.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 14.3 · 91% clinician	no trial data cached
Multiple organ dysfunction syndrome	81	20.8 16.8–25.8ROR 21.3 · χ² 1,503 / p <1e-300	20.6 EB05 17.1 · IC025 +3.8 3/3 methods agree	Not in label — unassessed	serious PRR 12.3 · 95% clinician	no trial data cached
White blood cell count decreased	73	4.8 3.8–6.0ROR 4.9 · χ² 217 / p 2e-49	4.7 EB05 3.8 · IC025 +1.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 3.9	no trial data cached
Ascites	62	15.1 11.8–19.3ROR 15.4 · χ² 800 / p 2e-176	14.9 EB05 12.0 · IC025 +3.3 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 9.1	no trial data cached
Aspartate aminotransferase increased	57	7.7 5.9–9.9ROR 7.8 · χ² 325 / p 7e-73	7.3 EB05 5.8 · IC025 +2.4 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.8	no trial data cached
Cytopenia	57	34.2 26.4–44.3ROR 34.9 · χ² 1,797 / p <1e-300	33.7 EB05 27.0 · IC025 +4.3 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 20.5 · 96% 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.

Cytokine release syndrome — n=133, PRR 50.2
Neoplasm progression — n=155, PRR 31.7
Thrombotic microangiopathy — n=31, PRR 22.9
Neurotoxicity — n=55, PRR 22.7
Hyperbilirubinaemia — n=30, PRR 20.8
Multiple organ dysfunction syndrome — n=81, PRR 20.8
Liver function test increased — n=26, PRR 8.7
Hyperglycaemia — n=44, PRR 8.7
Hyponatraemia — n=54, PRR 6.9

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 Inotuzumab Ozogamicin?

In FDA FAERS, the most frequently co-reported reaction terms for Inotuzumab Ozogamicin are febrile neutropenia, neoplasm progression, thrombocytopenia, sepsis, cytokine release syndrome, 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 Inotuzumab Ozogamicin have an FDA boxed warning?

Yes. The current FDA label carries a boxed warning: HEPATOTOXICITY, INCLUDING HEPATIC VENO-OCCLUSIVE DISEASE (VOD) (ALSO KNOWN AS SINUSOIDAL OBSTRUCTION SYNDROME) and INCREASED RISK OF POST-HEMATOPOIETIC STEM CELL TRANSPLANT (HSCT) NON-RELAPSE MORTALITY WARNING: HEPAT.

Do FAERS signals prove that Inotuzumab Ozogamicin 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 cc7014b1-c775-411d-b374-8113248b4077, effective 20260206; matched on openfda.generic_name.exact:"INOTUZUMAB OZOGAMICIN")
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, 97 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.