Bendamustine HCL side effects: what 15,416 FDA adverse event reports show
Drug class
Alkylating drug
Label matched
Bendamustine Hcl (Bendamustine)
Who reports
15,416 reports · 96% serious · 3,338 with death outcome · 40% female
Used for
Bendamustine Hydrochloride for Injection is an alkylating drug indicated for treatment of patients with: Chronic lymphocytic leukemia (CLL). Efficacy relative to first line therapies other than chlorambucil has not been established. ( 1.1 ) Indolent B-cell non-Hodgkin lymphoma (NHL) that has progressed during or within six months of treatment with rituximab or a rituximab-containing regimen.
What it is
Bendamustine hydrochloride is an alkylating agent.
Boxed warning
None in the current label
Causality screen of the 40 strongest signals
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.
- 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. 1,007 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 |
|---|---|---|---|---|---|---|
| Follicular lymphoma refractory | 22 | 797.5 470.6–1,351.4ROR 798.6 · χ² 10,481 / p <1e-300 | 348.5 EB05 242.6 · IC025 +4.7 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=22 · 100% clinician | not reported in cached trials |
| Marginal zone lymphoma recurrent | 16 | 692.2 378.7–1,265.3ROR 693.0 · χ² 6,835 / p <1e-300 | 295.5 EB05 192.9 · IC025 +4.1 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=16 | not reported in cached trials |
| Follicular lymphoma recurrent | 11 | 245.9 129.3–467.6ROR 246.1 · χ² 2,065 / p <1e-300 | 153.3 EB05 91.3 · IC025 +3.4 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=11 | not reported in cached trials |
| Splenic marginal zone lymphoma | 11 | 230.5 121.6–437.0ROR 230.7 · χ² 1,954 / p <1e-300 | 147.2 EB05 87.7 · IC025 +3.3 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=11 | not reported in cached trials |
| Follicular lymphoma | 121 | 225.1 185.8–272.7ROR 226.9 · χ² 22,924 / p <1e-300 | 187.2 EB05 160.8 · IC025 +6.5 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=117 | not reported in cached trials |
| Humoral immune defect | 52 | 221.4 165.2–296.8ROR 222.2 · χ² 9,604 / p <1e-300 | 177.8 EB05 140.8 · IC025 +5.6 3/3 methods agree | Not in label — unassessed | serious n=45 · 100% clinician | not reported in cached trials |
| Diffuse large b-cell lymphoma recurrent | 293 | 215.1 190.3–243.1ROR 219.2 · χ² 53,629 / p <1e-300 | 183.3 EB05 166.3 · IC025 +6.9 3/3 methods agree | Labeled (related wording) related wording | serious n=292 · 96% clinician | not reported in cached trials |
| Blood immunoglobulin m abnormal | 14 | 211.0 120.1–370.6ROR 211.2 · χ² 2,350 / p <1e-300 | 146.4 EB05 92.7 · IC025 +3.7 3/3 methods agree | Lab value / disease marker | serious n=14 | not reported in cached trials |
| B-cell lymphoma recurrent | 70 | 201.9 157.1–259.4ROR 202.8 · χ² 11,989 / p <1e-300 | 167.6 EB05 137.2 · IC025 +5.9 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=69 · 90% clinician | not reported in cached trials |
| Mantle cell lymphoma recurrent | 55 | 200.5 151.1–266.0ROR 201.2 · χ² 9,323 / p <1e-300 | 164.6 EB05 131.2 · IC025 +5.6 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=55 · 100% clinician | not reported in cached trials |
| Fungal disease carrier | 13 | 200.4 111.9–358.9ROR 200.6 · χ² 2,074 / p <1e-300 | 139.3 EB05 86.6 · IC025 +3.6 3/3 methods agree | Reporting / coding artifact | serious n=13 | not reported in cached trials |
| B-cell lymphoma refractory | 10 | 169.8 88.0–327.7ROR 169.9 · χ² 1,343 / p 2e-294 | 117.6 EB05 68.3 · IC025 +3.1 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=10 | not reported in cached trials |
| Lymphoma transformation | 38 | 160.3 114.5–224.3ROR 160.7 · χ² 5,231 / p <1e-300 | 133.8 EB05 101.7 · IC025 +5.1 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=38 · 95% clinician | not reported in cached trials |
| Blood immunoglobulin g abnormal | 16 | 148.0 88.3–248.0ROR 148.1 · χ² 1,973 / p <1e-300 | 115.4 EB05 75.3 · IC025 +3.9 3/3 methods agree | Lab value / disease marker | serious n=16 | not reported in cached trials |
| Endocarditis noninfective | 13 | 131.1 74.2–231.7ROR 131.2 · χ² 1,413 / p <1e-300 | 102.0 EB05 63.5 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=13 | not reported in cached trials |
| Chronic lymphocytic leukaemia recurrent | 59 | 126.6 97.0–165.3ROR 127.1 · χ² 6,604 / p <1e-300 | 111.7 EB05 89.7 · IC025 +5.4 3/3 methods agree | Labeled (related wording) related wording | serious n=59 | not reported in cached trials |
| Refractory cancer | 17 | 115.7 70.5–189.9ROR 115.9 · χ² 1,676 / p <1e-300 | 95.5 EB05 63.1 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious n=17 | not reported in cached trials |
| Reticulocytopenia | 11 | 111.8 60.4–206.7ROR 111.8 · χ² 1,015 / p 6e-223 | 88.0 EB05 52.4 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=11 | not reported in cached trials |
| Blood stem cell harvest failure | 11 | 108.5 58.7–200.5ROR 108.6 · χ² 987 / p 8e-217 | 85.9 EB05 51.2 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=11 | not reported in cached trials |
| Mantle cell lymphoma | 101 | 97.0 79.3–118.7ROR 97.7 · χ² 8,863 / p <1e-300 | 89.1 EB05 75.4 · IC025 +5.6 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=100 · ♀ 17% (drug 40%) · 96% clinician | not reported in cached trials |
| Vaccine interaction | 20 | 93.8 59.6–147.5ROR 93.9 · χ² 1,630 / p <1e-300 | 81.2 EB05 55.5 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=13 · 100% clinician | not reported in cached trials |
| Diffuse large b-cell lymphoma refractory | 58 | 90.5 69.4–117.9ROR 90.8 · χ² 4,723 / p <1e-300 | 82.6 EB05 66.2 · IC025 +5.2 3/3 methods agree | Labeled (related wording) related wording | serious n=58 · ♀ 74% (drug 40%) · 98% clinician | not reported in cached trials |
| Human polyomavirus infection | 29 | 80.4 55.3–116.9ROR 80.5 · χ² 2,070 / p <1e-300 | 72.4 EB05 52.9 · IC025 +4.4 3/3 methods agree | Not in label — unassessed | serious n=29 · ♀ 0% (drug 40%) · 100% clinician | not reported in cached trials |
| Breakthrough covid-19 | 13 | 80.3 45.9–140.6ROR 80.4 · χ² 888 / p 2e-195 | 68.6 EB05 42.6 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=13 | not reported in cached trials |
| Primary amyloidosis | 14 | 79.6 46.4–136.4ROR 79.6 · χ² 952 / p 2e-209 | 68.4 EB05 43.3 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=14 | not reported in cached trials |
| Diffuse large b-cell lymphoma | 414 | 78.0 70.7–86.0ROR 80.1 · χ² 29,685 / p <1e-300 | 73.5 EB05 67.8 · IC025 +5.9 3/3 methods agree | Labeled (related wording) related wording | serious PRR 44.8 · 97% clinician | not reported in cached trials |
| Marginal zone lymphoma | 11 | 74.5 40.6–136.7ROR 74.6 · χ² 688 / p 7e-152 | 63.3 EB05 37.7 · IC025 +3.1 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=11 | not reported in cached trials |
| Candida pneumonia | 16 | 70.6 42.7–116.7ROR 70.7 · χ² 978 / p 6e-215 | 62.4 EB05 40.7 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious n=16 | not reported in cached trials |
| Cystitis viral | 18 | 67.4 42.0–108.2ROR 67.5 · χ² 1,059 / p 1e-232 | 60.3 EB05 40.4 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=18 | not reported in cached trials |
| Jc virus infection | 68 | 60.4 47.4–77.0ROR 60.7 · χ² 3,747 / p <1e-300 | 57.0 EB05 46.5 · IC025 +5.0 3/3 methods agree | Labeled (related wording) related wording | serious n=68 · ♀ 61% (drug 40%) · 100% clinician | not reported in cached trials |
| Campylobacter infection | 35 | 59.6 42.5–83.5ROR 59.7 · χ² 1,874 / p <1e-300 | 55.4 EB05 41.7 · IC025 +4.4 3/3 methods agree | Not in label — unassessed | serious n=33 · 100% clinician | not reported in cached trials |
| Progressive multifocal leukoencephalopathy | 321 | 55.0 49.3–61.5ROR 56.2 · χ² 16,313 / p <1e-300 | 52.7 EB05 48.1 · IC025 +5.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 31.9 · 97% clinician | not reported in cached trials |
| Blood lactate dehydrogenase abnormal | 25 | 52.5 35.2–78.2ROR 52.6 · χ² 1,166 / p 9e-256 | 48.8 EB05 34.7 · IC025 +4.0 3/3 methods agree | Lab value / disease marker | serious n=25 · 96% clinician | not reported in cached trials |
| Diffuse large b-cell lymphoma stage iv | 12 | 52.4 29.5–93.3ROR 52.5 · χ² 534 / p 2e-118 | 47.0 EB05 28.6 · IC025 +3.1 3/3 methods agree | Labeled (related wording) related wording | serious n=12 | not reported in cached trials |
| Cytomegalovirus infection reactivation | 156 | 51.6 44.0–60.5ROR 52.1 · χ² 7,403 / p <1e-300 | 49.4 EB05 43.2 · IC025 +5.2 3/3 methods agree | Labeled (related wording) related wording | serious n=155 · 99% clinician | not reported in cached trials |
| Neutropenic infection | 34 | 49.6 35.2–69.8ROR 49.7 · χ² 1,514 / p <1e-300 | 46.7 EB05 34.9 · IC025 +4.3 3/3 methods agree | Labeled (related wording) related wording | serious n=34 · ♀ 65% (drug 40%) · 97% clinician | not reported in cached trials |
| Campylobacter gastroenteritis | 20 | 47.7 30.6–74.5ROR 47.8 · χ² 839 / p 9e-185 | 44.3 EB05 30.3 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious n=20 · 100% clinician | not reported in cached trials |
| Bone marrow infiltration | 13 | 47.4 27.3–82.4ROR 47.4 · χ² 526 / p 1e-116 | 43.1 EB05 26.8 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=13 | not reported in cached trials |
| Peripheral t-cell lymphoma unspecified | 19 | 45.5 28.8–71.9ROR 45.6 · χ² 757 / p 5e-167 | 42.3 EB05 28.6 · IC025 +3.6 3/3 methods agree | Labeled (related wording) related wording | serious n=19 | not reported in cached trials |
| Blood uric acid abnormal | 13 | 45.2 26.0–78.5ROR 45.2 · χ² 501 / p 2e-111 | 41.3 EB05 25.7 · IC025 +3.1 3/3 methods agree | Lab value / disease marker | serious n=13 | not reported in cached trials |
Trial evidence (ClinicalTrials.gov)
✓ Trial adverse-event data found on ClinicalTrials.gov
Largest completed trials with posted results that list Bendamustine as a study intervention. The right-hand column of the signal table shows whether each FAERS term was also recorded in these trials, with a real denominator (0 of 40 signal terms matched).
- NCT01476787 — Combined Rituximab and Lenalidomide Treatment for Untreated Patients With Follicular Lymphoma (N=1030, PHASE3; 379 AE terms posted; arms: Rituximab-Lenalidomide; Investigator Choice Rituximab-CHOP; Investigator Choice Rituximab-CVP; Investigator Choice Rituximab-Bendamusti)
Caveats: trial populations, doses and follow-up differ from the reporting population; AE terms are sponsor-coded and matched here by wording; absence from a trial list means the term was not reported above the sponsor's frequency threshold, not that it cannot occur.
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 |
|---|---|---|---|---|---|---|
| Disease progression | 2,242 | 26.3 25.3–27.4ROR 30.7 · χ² 53,895 / p <1e-300 | 25.9 EB05 25.0 · IC025 +4.6 3/3 methods agree | Reporting / coding artifact | serious PRR 17.3 · 97% clinician | not reported in cached trials |
| Off label use (used outside approved label) | 2,037 | 3.2 3.1–3.3ROR 3.5 · χ² 3,200 / p <1e-300 | 3.2 EB05 3.1 · IC025 +1.6 3/3 methods agree | Reporting / coding artifact | serious PRR 3.4 · 93% clinician | not reported in cached trials |
| Neutropenia (low neutrophils (infection-fighting cells)) | 1,169 | 11.8 11.2–12.5ROR 12.7 · χ² 11,553 / p <1e-300 | 11.7 EB05 11.2 · IC025 +3.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 7.3 · 97% clinician | NCT01476787: 6/112 (5.4%) on Bendamustine (serious AE) |
| Pyrexia (fever) | 1,047 | 4.1 3.9–4.4ROR 4.4 · χ² 2,507 / p <1e-300 | 4.1 EB05 3.9 · IC025 +1.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.0 · 94% clinician | NCT01476787: 1/112 (0.9%) on Bendamustine (serious AE) |
| Drug ineffective (drug did not work) | 964 | 1.0 0.9–1.1ROR 1.0 · χ² 0 / p 0.453 | 1.0 EB05 0.9 · IC025 -0.1 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 1.7 · 94% clinician | not reported in cached trials |
| Thrombocytopenia (low platelets) | 950 | 11.7 11.0–12.4ROR 12.4 · χ² 9,236 / p <1e-300 | 11.6 EB05 11.0 · IC025 +3.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 7.1 · 97% clinician | NCT01476787: 3/507 (0.6%) on Bendamustine (serious AE) |
| Pneumonia (lung infection) | 843 | 3.6 3.3–3.8ROR 3.7 · χ² 1,565 / p <1e-300 | 3.5 EB05 3.3 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.2 · 95% clinician | NCT01476787: 2/365 (0.5%) on Bendamustine (serious AE) |
| Febrile neutropenia | 797 | 16.6 15.5–17.7ROR 17.4 · χ² 11,530 / p <1e-300 | 16.4 EB05 15.4 · IC025 +3.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 9.9 · 98% clinician | NCT01476787: 6/112 (5.4%) on Bendamustine (serious AE) |
| Anaemia (low red blood cells) | 773 | 5.5 5.2–5.9ROR 5.8 · χ² 2,876 / p <1e-300 | 5.5 EB05 5.2 · IC025 +2.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.6 · 93% clinician | NCT01476787: 1/507 (0.2%) on Bendamustine (serious AE) |
| Covid-19 | 744 | 5.7 5.4–6.2ROR 6.0 · χ² 2,919 / p <1e-300 | 5.7 EB05 5.4 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 5.8 · 97% clinician | not reported in cached trials |
| Death | 702 | 1.1 1.0–1.2ROR 1.1 · χ² 8 / p 0.003 | 1.1 EB05 1.0 · IC025 +0.0 | Outcome field, not a reaction | serious PRR 0.7 · 94% clinician | NCT01476787: 1/365 (0.3%) on Bendamustine (serious AE) |
| Infection | 577 | 5.5 5.0–5.9ROR 5.6 · χ² 2,104 / p <1e-300 | 5.4 EB05 5.1 · IC025 +2.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.1 · 95% clinician | NCT01476787: 1/507 (0.2%) on Bendamustine (serious AE) |
| Diarrhoea (diarrhea) | 512 | 1.1 1.0–1.2ROR 1.1 · χ² 3 / p 0.036 | 1.1 EB05 1.0 · IC025 -0.0 PRR-only: not supported by EBGM or IC | Labeled adverse reaction exact term | serious PRR 1.1 · 94% clinician | NCT01476787: 4/507 (0.8%) on Bendamustine (serious AE) |
| Sepsis (blood infection) | 470 | 5.7 5.3–6.3ROR 5.9 · χ² 1,841 / p <1e-300 | 5.7 EB05 5.3 · IC025 +2.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.5 · 95% clinician | NCT01476787: 1/507 (0.2%) on Bendamustine (serious AE) |
| Pancytopenia (all blood cells low) | 458 | 11.3 10.3–12.3ROR 11.6 · χ² 4,249 / p <1e-300 | 11.1 EB05 10.3 · IC025 +3.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.8 · 95% clinician | NCT01476787: 2/507 (0.4%) on Bendamustine (serious AE) |
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.
- Humoral immune defect — n=52, PRR 221.4
- Vaccine interaction — n=20, PRR 93.8
- Human polyomavirus infection — n=29, PRR 80.4
- Campylobacter infection — n=35, PRR 59.6
- Campylobacter gastroenteritis — n=20, PRR 47.7
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 Bendamustine?
In FDA FAERS, the most frequently co-reported reaction terms for Bendamustine are neutropenia, pyrexia, thrombocytopenia, pneumonia, febrile neutropenia, anaemia. 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 Bendamustine have an FDA boxed warning?
No. The FDA label retrieved for Bendamustine has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Bendamustine 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 40f6f58d-d9ac-4f65-9fc7-16984bf1f180, effective 20260511; matched on
openfda.generic_name.exact:"BENDAMUSTINE HCL") - 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, 1,047 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 - ClinicalTrials.gov API v2 (query
BENDAMUSTINE, results-bearing studies sorted by enrollment)
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.