Nelarabine side effects: what 956 FDA adverse event reports show

Nelarabine · 37 reaction terms · 700 drug–reaction co-reports · data 2026-09-14

Drug class

Nucleoside Metabolic Inhibitor

FDA label (Established Pharmacologic Class) · compare the class

Who reports

956 reports · 96% serious · 210 with death outcome · 30% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Nelarabine injection is indicated for the treatment of T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL) in adult and pediatric patients age 1 year and older whose disease has not responded to or has relapsed following treatment with at least two chemotherapy regimens.

FDA label, Indications and Usage

What it is

Nelarabine injection (nelarabine) is a prodrug of the cytotoxic deoxyguanosine analogue, 9-β- D arabinofuranosylguanine (ara-G).

FDA label, Description section

Boxed warning

NEUROLOGIC ADVERSE REACTIONS See full prescribing information for complete boxed warning. Severe neurologic adverse reactions have been reported with the use of nelarabine injection. These adverse reactions have incl.

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 23 strongest signals

Labeled — boxed warning 1Labeled adverse reaction 9Labeled (related wording) 3Reporting / coding artifact 2Not in label — unassessed 8

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.
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. 14 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
Neurotoxicity	60	76.0 59.5–97.1ROR 81.0 · χ² 4,354 / p <1e-300	74.0 EB05 59.6 · IC025 +5.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 45.8 · 92% clinician	no trial data cached
Polyneuropathy	25	46.2 31.4–68.0ROR 47.4 · χ² 1,059 / p 1e-232	44.6 EB05 31.8 · IC025 +3.9 3/3 methods agree	Not in label — unassessed	serious PRR 27.8	no trial data cached
Ataxia	23	42.4 28.3–63.5ROR 43.4 · χ² 888 / p 2e-195	41.0 EB05 28.8 · IC025 +3.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 27.4 · 96% clinician	no trial data cached
Pneumocystis jirovecii pneumonia	19	41.8 26.7–65.2ROR 42.6 · χ² 715 / p 9e-158	40.1 EB05 27.2 · IC025 +3.6 3/3 methods agree	Not in label — unassessed	serious PRR 24.9	no trial data cached
Bacteraemia	14	26.1 15.5–43.9ROR 26.5 · χ² 313 / p 2e-70	25.2 EB05 15.9 · IC025 +2.9 3/3 methods agree	Not in label — unassessed	serious PRR 15.7	no trial data cached
Hyperbilirubinaemia	12	25.6 14.6–44.9ROR 25.9 · χ² 259 / p 1e-58	24.6 EB05 14.8 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 15.6	no trial data cached
Febrile neutropenia	75	24.9 20.0–30.9ROR 26.9 · χ² 1,698 / p <1e-300	24.7 EB05 20.4 · IC025 +4.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 14.7 · 96% clinician	no trial data cached
Bone marrow failure	23	24.7 16.5–37.0ROR 25.3 · χ² 499 / p 7e-111	24.2 EB05 17.0 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 14.8 · 91% clinician	no trial data cached
Encephalopathy	24	21.5 14.5–31.9ROR 22.0 · χ² 449 / p 5e-100	21.1 EB05 14.9 · IC025 +3.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 12.9 · 100% clinician	no trial data cached
Sensory disturbance	13	17.7 10.3–30.4ROR 17.9 · χ² 188 / p 4e-43	16.8 EB05 9.8 · IC025 +2.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 16.3	no trial data cached
Therapy partial responder	11	16.0 8.9–28.9ROR 16.2 · χ² 140 / p 1e-32	14.7 EB05 7.7 · IC025 +2.3 3/3 methods agree	Reporting / coding artifact	serious PRR 11.6	no trial data cached
Nervous system disorder	22	15.4 10.2–23.3ROR 15.8 · χ² 283 / p 1e-63	15.0 EB05 10.1 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 10.3	no trial data cached
Septic shock	30	15.2 10.7–21.7ROR 15.7 · χ² 385 / p 4e-86	14.9 EB05 10.8 · IC025 +3.0 3/3 methods agree	Not in label — unassessed	serious PRR 8.8 · 100% clinician	no trial data cached
Rhabdomyolysis (muscle breakdown)	28	14.8 10.2–21.3ROR 15.2 · χ² 346 / p 1e-77	14.4 EB05 10.2 · IC025 +2.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.9	no trial data cached
Neuropathy peripheral (nerve damage in hands/feet)	60	13.9 10.9–17.8ROR 14.8 · χ² 710 / p 1e-156	13.8 EB05 11.0 · IC025 +3.2 3/3 methods agree	Labeled — boxed warning synonym match	serious PRR 9.4 · 92% clinician	no trial data cached
Hepatotoxicity (liver damage)	13	12.9 7.5–22.1ROR 13.0 · χ² 131 / p 1e-30	11.5 EB05 6.4 · IC025 +2.2 3/3 methods agree	Not in label — unassessed	serious PRR 7.8	no trial data cached
Myelosuppression	19	12.3 7.9–19.1ROR 12.5 · χ² 186 / p 2e-42	11.4 EB05 7.2 · IC025 +2.5 3/3 methods agree	Not in label — unassessed	serious PRR 7.3	no trial data cached
Altered state of consciousness	10	10.2 5.5–18.9ROR 10.3 · χ² 74 / p 4e-18	8.1 EB05 4.3 · IC025 +1.7 3/3 methods agree	Labeled (related wording) related wording	serious PRR 6.1	no trial data cached
Blood creatine phosphokinase increased	13	9.8 5.7–16.7ROR 9.9 · χ² 94 / p 2e-22	8.1 EB05 4.8 · IC025 +1.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 6.0	no trial data cached
Mucosal inflammation	10	8.4 4.5–15.6ROR 8.5 · χ² 58 / p 1e-14	6.6 EB05 3.7 · IC025 +1.6 3/3 methods agree	Labeled (related wording) related wording	serious PRR 5.3	no trial data cached
Neutrophil count decreased	15	8.1 4.9–13.4ROR 8.2 · χ² 87 / p 6e-21	6.8 EB05 4.3 · IC025 +1.9 3/3 methods agree	Labeled (related wording) related wording	serious PRR 5.3	no trial data cached
Neutropenia (low neutrophils (infection-fighting cells))	49	7.9 6.0–10.4ROR 8.3 · χ² 292 / p 1e-65	7.5 EB05 5.9 · IC025 +2.4 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.9	no trial data cached
Malignant neoplasm progression	34	7.3 5.3–10.2ROR 7.6 · χ² 180 / p 2e-41	6.8 EB05 5.0 · IC025 +2.2 3/3 methods agree	Reporting / coding artifact	serious PRR 4.5 · 91% 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
Febrile neutropenia	75	24.9 20.0–30.9ROR 26.9 · χ² 1,698 / p <1e-300	24.7 EB05 20.4 · IC025 +4.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 14.7 · 96% clinician	no trial data cached
Neuropathy peripheral (nerve damage in hands/feet)	60	13.9 10.9–17.8ROR 14.8 · χ² 710 / p 1e-156	13.8 EB05 11.0 · IC025 +3.2 3/3 methods agree	Labeled — boxed warning synonym match	serious PRR 9.4 · 92% clinician	no trial data cached
Neurotoxicity	60	76.0 59.5–97.1ROR 81.0 · χ² 4,354 / p <1e-300	74.0 EB05 59.6 · IC025 +5.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 45.8 · 92% clinician	no trial data cached
Neutropenia (low neutrophils (infection-fighting cells))	49	7.9 6.0–10.4ROR 8.3 · χ² 292 / p 1e-65	7.5 EB05 5.9 · IC025 +2.4 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.9	no trial data cached
Malignant neoplasm progression	34	7.3 5.3–10.2ROR 7.6 · χ² 180 / p 2e-41	6.8 EB05 5.0 · IC025 +2.2 3/3 methods agree	Reporting / coding artifact	serious PRR 4.5 · 91% clinician	no trial data cached
Septic shock	30	15.2 10.7–21.7ROR 15.7 · χ² 385 / p 4e-86	14.9 EB05 10.8 · IC025 +3.0 3/3 methods agree	Not in label — unassessed	serious PRR 8.8 · 100% clinician	no trial data cached
Rhabdomyolysis (muscle breakdown)	28	14.8 10.2–21.3ROR 15.2 · χ² 346 / p 1e-77	14.4 EB05 10.2 · IC025 +2.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.9	no trial data cached
Polyneuropathy	25	46.2 31.4–68.0ROR 47.4 · χ² 1,059 / p 1e-232	44.6 EB05 31.8 · IC025 +3.9 3/3 methods agree	Not in label — unassessed	serious PRR 27.8	no trial data cached
Encephalopathy	24	21.5 14.5–31.9ROR 22.0 · χ² 449 / p 5e-100	21.1 EB05 14.9 · IC025 +3.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 12.9 · 100% clinician	no trial data cached
Bone marrow failure	23	24.7 16.5–37.0ROR 25.3 · χ² 499 / p 7e-111	24.2 EB05 17.0 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 14.8 · 91% clinician	no trial data cached
Ataxia	23	42.4 28.3–63.5ROR 43.4 · χ² 888 / p 2e-195	41.0 EB05 28.8 · IC025 +3.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 27.4 · 96% clinician	no trial data cached
Nervous system disorder	22	15.4 10.2–23.3ROR 15.8 · χ² 283 / p 1e-63	15.0 EB05 10.1 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 10.3	no trial data cached
Myelosuppression	19	12.3 7.9–19.1ROR 12.5 · χ² 186 / p 2e-42	11.4 EB05 7.2 · IC025 +2.5 3/3 methods agree	Not in label — unassessed	serious PRR 7.3	no trial data cached
Pneumocystis jirovecii pneumonia	19	41.8 26.7–65.2ROR 42.6 · χ² 715 / p 9e-158	40.1 EB05 27.2 · IC025 +3.6 3/3 methods agree	Not in label — unassessed	serious PRR 24.9	no trial data cached
Neutrophil count decreased	15	8.1 4.9–13.4ROR 8.2 · χ² 87 / p 6e-21	6.8 EB05 4.3 · IC025 +1.9 3/3 methods agree	Labeled (related wording) related wording	serious PRR 5.3	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.

Polyneuropathy — n=25, PRR 46.2
Bone marrow failure — n=23, PRR 24.7
Septic shock — n=30, PRR 15.2

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 Nelarabine?

In FDA FAERS, the most frequently co-reported reaction terms for Nelarabine are febrile neutropenia, neuropathy peripheral, neurotoxicity, neutropenia, septic shock, rhabdomyolysis. 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 Nelarabine have an FDA boxed warning?

Yes. The current FDA label carries a boxed warning: NEUROLOGIC ADVERSE REACTIONS See full prescribing information for complete boxed warning. Severe neurologic adverse reactions have been reported with the use of nelarabine injection. These adverse reactions have incl.

Do FAERS signals prove that Nelarabine 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 03ad6056-0e71-4e7c-842a-a5f87649bdcd, effective 20240807; matched on openfda.generic_name.exact:"NELARABINE")
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, 37 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.