Rituximab-Arrx side effects: what 379 FDA adverse event reports show

Rituximab-Arrx · Riabni · 15 reaction terms · 385 drug–reaction co-reports · data 2026-09-14

Drug class

CD20-directed Cytolytic Antibody

FDA label (Established Pharmacologic Class) · compare the class

Brand names

Riabni

openFDA label

Who reports

379 reports · 16% serious · 14 with death outcome · 59% female

openFDA FAERS counts, all years, deduplication not applied

Used for

RIABNI is a CD20-directed cytolytic antibody indicated for the treatment of: Adult patients with Non-Hodgkin's Lymphoma (NHL) ( 1.1 ). Relapsed or refractory, low grade or follicular, CD20-positive B-cell NHL as a single agent. Previously untreated fol.

FDA label, Indications and Usage

What it is

Rituximab-arrx is a genetically engineered chimeric murine/human monoclonal IgG1 kappa antibody directed against the CD20 antigen. Rituximab-arrx has an approximate molecular weight of 145 kD. Rituximab-arrx is produced in a mammalian cell (Chinese Hamster Ovary) suspension culture in a nutrient medium.

FDA label, Description section

Boxed warning

FATAL INFUSION-RELATED REACTIONS, SEVERE MUCOCUTANEOUS REACTIONS, HEPATITIS B VIRUS REACTIVATION and PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY WARNING: FATAL INFUSION-RELATED REACTIONS, SEVERE MUCOCUTANEOUS REACTIONS, HEPATITIS B VIRUS REACTIVATION and PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY See full prescribing information for complete boxed warning.

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 12 strongest signals

Labeled (related wording) 2Likely indication confounding 1Reporting / coding artifact 2Lab value / disease marker 1Not in label — unassessed 6

What the badges mean

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. 3 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
Circumstance or information capable of leading to medication error	116	192.0 164.9–223.5ROR 276.2 · χ² 21,803 / p <1e-300	185.5 EB05 158.8 · IC025 +6.4 3/3 methods agree	Labeled (related wording) related wording	–	no trial data cached
Product storage error	165	105.7 94.2–118.6ROR 186.4 · χ² 17,045 / p <1e-300	104.3 EB05 91.6 · IC025 +6.1 3/3 methods agree	Reporting / coding artifact	–	no trial data cached
Intercepted product preparation error	16	72.8 45.0–117.6ROR 75.9 · χ² 1,061 / p 4e-233	67.1 EB05 43.8 · IC025 +3.7 3/3 methods agree	Not in label — unassessed	–	no trial data cached
Helicobacter infection	8	43.4 21.9–86.3ROR 44.4 · χ² 291 / p 2e-65	39.6 EB05 21.4 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 164.1	no trial data cached
Hand deformity	9	38.1 20.0–72.6ROR 39.0 · χ² 289 / p 4e-65	35.4 EB05 19.9 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 148.0	no trial data cached
Folliculitis	7	37.5 18.0–78.2ROR 38.2 · χ² 214 / p 1e-48	34.1 EB05 17.5 · IC025 +2.1 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious PRR 157.6	no trial data cached
Joint range of motion decreased	8	33.1 16.7–65.8ROR 33.8 · χ² 218 / p 1e-49	30.8 EB05 16.5 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 151.0	no trial data cached
Deformity	5	29.5 12.4–70.5ROR 29.9 · χ² 111 / p 3e-26	25.3 EB05 9.2 · IC025 +1.5 3/3 methods agree	Not in label — unassessed	serious PRR 120.8	no trial data cached
Glossodynia (burning tongue/mouth pain)	9	22.3 11.7–42.5ROR 22.8 · χ² 162 / p 2e-37	20.9 EB05 10.9 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 115.4	no trial data cached
Systemic lupus erythematosus	9	14.1 7.4–26.8ROR 14.4 · χ² 97 / p 4e-23	12.0 EB05 5.7 · IC025 +1.9 3/3 methods agree	Labeled (related wording) related wording	serious PRR 51.7	no trial data cached
Bone density decreased	6	10.5 4.7–23.2ROR 10.6 · χ² 42 / p 4e-11	7.2 EB05 3.2 · IC025 +1.2 3/3 methods agree	Lab value / disease marker	serious PRR 46.8	no trial data cached
Accidental exposure to product	17	9.4 5.9–15.0ROR 9.8 · χ² 120 / p 3e-28	8.2 EB05 5.2 · IC025 +2.1 3/3 methods agree	Reporting / coding artifact	–	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
Product storage error	165	105.7 94.2–118.6ROR 186.4 · χ² 17,045 / p <1e-300	104.3 EB05 91.6 · IC025 +6.1 3/3 methods agree	Reporting / coding artifact	–	no trial data cached
Circumstance or information capable of leading to medication error	116	192.0 164.9–223.5ROR 276.2 · χ² 21,803 / p <1e-300	185.5 EB05 158.8 · IC025 +6.4 3/3 methods agree	Labeled (related wording) related wording	–	no trial data cached
Accidental exposure to product	17	9.4 5.9–15.0ROR 9.8 · χ² 120 / p 3e-28	8.2 EB05 5.2 · IC025 +2.1 3/3 methods agree	Reporting / coding artifact	–	no trial data cached
Intercepted product preparation error	16	72.8 45.0–117.6ROR 75.9 · χ² 1,061 / p 4e-233	67.1 EB05 43.8 · IC025 +3.7 3/3 methods agree	Not in label — unassessed	–	no trial data cached
Systemic lupus erythematosus	9	14.1 7.4–26.8ROR 14.4 · χ² 97 / p 4e-23	12.0 EB05 5.7 · IC025 +1.9 3/3 methods agree	Labeled (related wording) related wording	serious PRR 51.7	no trial data cached
Glossodynia (burning tongue/mouth pain)	9	22.3 11.7–42.5ROR 22.8 · χ² 162 / p 2e-37	20.9 EB05 10.9 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 115.4	no trial data cached
Hand deformity	9	38.1 20.0–72.6ROR 39.0 · χ² 289 / p 4e-65	35.4 EB05 19.9 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 148.0	no trial data cached
Joint range of motion decreased	8	33.1 16.7–65.8ROR 33.8 · χ² 218 / p 1e-49	30.8 EB05 16.5 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 151.0	no trial data cached
Helicobacter infection	8	43.4 21.9–86.3ROR 44.4 · χ² 291 / p 2e-65	39.6 EB05 21.4 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 164.1	no trial data cached
Folliculitis	7	37.5 18.0–78.2ROR 38.2 · χ² 214 / p 1e-48	34.1 EB05 17.5 · IC025 +2.1 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious PRR 157.6	no trial data cached
Bone density decreased	6	10.5 4.7–23.2ROR 10.6 · χ² 42 / p 4e-11	7.2 EB05 3.2 · IC025 +1.2 3/3 methods agree	Lab value / disease marker	serious PRR 46.8	no trial data cached
Deformity	5	29.5 12.4–70.5ROR 29.9 · χ² 111 / p 3e-26	25.3 EB05 9.2 · IC025 +1.5 3/3 methods agree	Not in label — unassessed	serious PRR 120.8	no trial data cached
Product preparation error	4	10.7 4.0–28.3ROR 10.8 · χ² 26 / p 2e-7	6.2 EB05 2.3 · IC025 +0.6 3/3 methods agree	Reporting / coding artifact	–	no trial data cached
Synovitis	3	9.2 3.0–28.4ROR 9.3 · χ² 14 / p 7e-5	4.8 EB05 1.7 · IC025 +0.0	Not in label — unassessed	serious PRR 34.5	no trial data cached
Pemphigus	3	13.4 4.3–41.2ROR 13.5 · χ² 23 / p 8e-7	6.8 EB05 2.1 · IC025 +0.2 3/3 methods agree	Likely indication confounding term in indications; also in warnings	serious PRR 47.9	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.

✓ A hand-written Bradford Hill causality assessment exists for this drug: Rituximab ↔ Serious infection.

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 Rituximab-Arrx?

In FDA FAERS, the most frequently co-reported reaction terms for Rituximab-Arrx are circumstance or information capable of leading to medication error, intercepted product preparation error, systemic lupus erythematosus, glossodynia, hand deformity, joint range of motion 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 Rituximab-Arrx have an FDA boxed warning?

Yes. The current FDA label carries a boxed warning: FATAL INFUSION-RELATED REACTIONS, SEVERE MUCOCUTANEOUS REACTIONS, HEPATITIS B VIRUS REACTIVATION and PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY WARNING: FATAL INFUSION-RELATED REACTIONS, SEVERE MUCOCUTANEOUS REACTIONS, HEPATITIS B VIRUS REACTIVATION and PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY See full prescribing information for complete boxed warning.

Do FAERS signals prove that Rituximab-Arrx 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 da1c4de7-0e5b-4f72-97ec-7a8d368f085f, effective 20260722; matched on openfda.generic_name.exact:"RITUXIMAB-ARRX")
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, 15 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.