Quizartinib side effects: what 634 FDA adverse event reports show

Quizartinib · Vanflyta · 10 reaction terms · 217 drug–reaction co-reports · data 2026-09-14

Drug class

Kinase inhibitor

FDA label, Indications wording

Brand names

Vanflyta

openFDA label

Who reports

634 reports · 63% serious · 100 with death outcome · 53% female

openFDA FAERS counts, all years, deduplication not applied

Used for

VANFLYTA is indicated in combination with standard cytarabine and anthracycline induction and cytarabine consolidation, and as maintenance monotherapy following consolidation chemotherapy, for the treatment of adult patients with newly diagnosed acute .

FDA label, Indications and Usage

What it is

VANFLYTA (quizartinib) is a kinase inhibitor for oral use.

FDA label, Description section

Boxed warning

QT PROLONGATION, TORSADES DE POINTES, and CARDIAC ARREST VANFLYTA prolongs the QT interval in a dose- and concentration-related manner [see Clinical Pharmacology (12.2) ] . Prior to VANFLYTA administration and periodically, monitor for hypokalemia or hypomagnesemia, and correct deficiencies.

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 10 strongest signals

Labeled — boxed warning 1Labeled adverse reaction 2Likely indication confounding 2Reporting / coding artifact 3Lab value / disease marker 2

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.
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. 0 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
Therapy change	12	41.2 23.5–72.2ROR 42.0 · χ² 431 / p 5e-96	38.8 EB05 23.7 · IC025 +3.0 3/3 methods agree	Reporting / coding artifact	serious n=4	no trial data cached
Acute myeloid leukaemia	15	31.9 19.3–52.6ROR 32.6 · χ² 418 / p 3e-93	30.7 EB05 19.8 · IC025 +3.1 3/3 methods agree	Likely indication confounding term in indications	serious PRR 29.1	no trial data cached
Electrocardiogram qt prolonged	33	30.4 21.8–42.3ROR 32.0 · χ² 908 / p 8e-200	29.9 EB05 22.2 · IC025 +3.8 3/3 methods agree	Labeled — boxed warning synonym match	serious PRR 23.8	no trial data cached
Full blood count decreased	15	24.6 14.9–40.6ROR 25.2 · χ² 317 / p 4e-71	23.9 EB05 15.3 · IC025 +2.9 3/3 methods agree	Lab value / disease marker	serious PRR 23.7	no trial data cached
Leukaemia	6	21.1 9.5–46.7ROR 21.2 · χ² 95 / p 8e-23	18.0 EB05 6.7 · IC025 +1.6 3/3 methods agree	Likely indication confounding term in indications; also in warnings	serious PRR 19.3	no trial data cached
Myelosuppression	19	18.5 11.9–28.8ROR 19.0 · χ² 297 / p 7e-67	18.0 EB05 11.9 · IC025 +2.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 16.8	no trial data cached
Febrile neutropenia	33	16.5 11.8–23.0ROR 17.3 · χ² 466 / p 1e-103	16.3 EB05 12.0 · IC025 +3.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 15.1	no trial data cached
Full blood count abnormal	5	15.7 6.6–37.6ROR 15.8 · χ² 55 / p 6e-14	11.2 EB05 3.8 · IC025 +1.2 3/3 methods agree	Lab value / disease marker	serious PRR 7.6	no trial data cached
No adverse event	68	12.7 10.1–15.9ROR 14.1 · χ² 726 / p 3e-160	12.5 EB05 10.1 · IC025 +3.1 3/3 methods agree	Reporting / coding artifact	–	no trial data cached
Laboratory test abnormal	11	12.3 6.9–22.2ROR 12.5 · χ² 104 / p 1e-24	10.5 EB05 5.5 · IC025 +2.0 3/3 methods agree	Reporting / coding artifact	serious PRR 17.0	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
No adverse event	68	12.7 10.1–15.9ROR 14.1 · χ² 726 / p 3e-160	12.5 EB05 10.1 · IC025 +3.1 3/3 methods agree	Reporting / coding artifact	–	no trial data cached
Febrile neutropenia	33	16.5 11.8–23.0ROR 17.3 · χ² 466 / p 1e-103	16.3 EB05 12.0 · IC025 +3.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 15.1	no trial data cached
Electrocardiogram qt prolonged	33	30.4 21.8–42.3ROR 32.0 · χ² 908 / p 8e-200	29.9 EB05 22.2 · IC025 +3.8 3/3 methods agree	Labeled — boxed warning synonym match	serious PRR 23.8	no trial data cached
Myelosuppression	19	18.5 11.9–28.8ROR 19.0 · χ² 297 / p 7e-67	18.0 EB05 11.9 · IC025 +2.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 16.8	no trial data cached
Full blood count decreased	15	24.6 14.9–40.6ROR 25.2 · χ² 317 / p 4e-71	23.9 EB05 15.3 · IC025 +2.9 3/3 methods agree	Lab value / disease marker	serious PRR 23.7	no trial data cached
Acute myeloid leukaemia	15	31.9 19.3–52.6ROR 32.6 · χ² 418 / p 3e-93	30.7 EB05 19.8 · IC025 +3.1 3/3 methods agree	Likely indication confounding term in indications	serious PRR 29.1	no trial data cached
Therapy change	12	41.2 23.5–72.2ROR 42.0 · χ² 431 / p 5e-96	38.8 EB05 23.7 · IC025 +3.0 3/3 methods agree	Reporting / coding artifact	serious n=4	no trial data cached
Laboratory test abnormal	11	12.3 6.9–22.2ROR 12.5 · χ² 104 / p 1e-24	10.5 EB05 5.5 · IC025 +2.0 3/3 methods agree	Reporting / coding artifact	serious PRR 17.0	no trial data cached
Leukaemia	6	21.1 9.5–46.7ROR 21.2 · χ² 95 / p 8e-23	18.0 EB05 6.7 · IC025 +1.6 3/3 methods agree	Likely indication confounding term in indications; also in warnings	serious PRR 19.3	no trial data cached
Full blood count abnormal	5	15.7 6.6–37.6ROR 15.8 · χ² 55 / p 6e-14	11.2 EB05 3.8 · IC025 +1.2 3/3 methods agree	Lab value / disease marker	serious PRR 7.6	no trial data cached

Unlabeled candidate signals

Every screened signal with n ≥ 20 was either labeled, an indication term, or an artifact pattern — no unlabeled candidate stood out in the top signals.

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 Quizartinib?

In FDA FAERS, the most frequently co-reported reaction terms for Quizartinib are febrile neutropenia, electrocardiogram qt prolonged, myelosuppression, full blood count decreased, acute myeloid leukaemia, leukaemia. 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 Quizartinib have an FDA boxed warning?

Yes. The current FDA label carries a boxed warning: QT PROLONGATION, TORSADES DE POINTES, and CARDIAC ARREST VANFLYTA prolongs the QT interval in a dose- and concentration-related manner [see Clinical Pharmacology (12.2) ] . Prior to VANFLYTA administration and periodically, monitor for hypokalemia or hypomagnesemia, and correct deficiencies.

Do FAERS signals prove that Quizartinib 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 29cdbcfe-497d-4e78-bb7b-2d4acafe8e86, effective 20260416; matched on openfda.generic_name.exact:"QUIZARTINIB")
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, 10 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.