Epcoritamab-Bysp side effects: what 1,271 FDA adverse event reports show
Drug class
Bispecific CD20-directed CD3 T Cell Engager
Brand names
Epkinly
Who reports
1,271 reports · 93% serious · 422 with death outcome · 42% female
Used for
EPKINLY is a bispecific CD20-directed CD3 T-cell engager indicated: For the treatment of adult patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL), not otherwise specified, including DLBCL arising from indolent lymphoma, and high-grade B-cell lymphoma after two or more lines of systemic therapy.
What it is
Epcoritamab-bysp is a bispecific CD20-directed CD3 T-cell engager; it is a humanized bispecific IgG1 antibody. Epcoritamab-bysp is manufactured in Chinese hamster ovary (CHO) cells using recombinant DNA technology and has an approximate molecular weight of 149 kDa.
Boxed warning
CYTOKINE RELEASE SYNDROME AND IMMUNE EFFECTOR CELL-ASSOCIATED NEUROTOXICITY SYNDROME Cytokine release syndrome (CRS), including serious or fatal reactions, can occur in patients receiving EPKINLY. Initiate treatment with the EPKINLY step-up dosage schedule to reduce the incidence and severity of CRS.
Causality screen of the 21 strongest signals
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.
- 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. 2 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 |
|---|---|---|---|---|---|---|
| Cytokine release syndrome | 450 | 398.8 369.8–430.2ROR 616.6 · χ² 174,070 / p <1e-300 | 382.9 EB05 354.2 · IC025 +7.9 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 242.7 · 99% clinician | no trial data cached |
| Cytomegalovirus infection | 36 | 35.8 25.9–49.4ROR 36.8 · χ² 1,180 / p 7e-259 | 35.1 EB05 26.5 · IC025 +4.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 21.1 · 100% clinician | no trial data cached |
| Blood lactate dehydrogenase increased | 24 | 24.8 16.7–36.9ROR 25.3 · χ² 525 / p 2e-116 | 24.4 EB05 17.2 · IC025 +3.4 3/3 methods agree | Lab value / disease marker | serious PRR 15.0 · 100% clinician | no trial data cached |
| Neutrophil count decreased | 55 | 22.4 17.3–29.0ROR 23.4 · χ² 1,104 / p 2e-242 | 22.2 EB05 17.7 · IC025 +3.8 3/3 methods agree | Labeled (related wording) related wording | serious PRR 15.5 · 100% clinician | no trial data cached |
| Covid-19 pneumonia | 13 | 18.0 10.5–31.0ROR 18.2 · χ² 192 / p 5e-44 | 17.2 EB05 10.0 · IC025 +2.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 11.3 | no trial data cached |
| Intestinal perforation | 10 | 14.7 7.9–27.2ROR 14.8 · χ² 114 / p 6e-27 | 12.9 EB05 6.4 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 9.1 | no trial data cached |
| Bacteraemia | 10 | 14.0 7.6–26.0ROR 14.1 · χ² 108 / p 1e-25 | 12.2 EB05 6.1 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 8.8 | no trial data cached |
| Pneumocystis jirovecii pneumonia | 8 | 13.2 6.6–26.3ROR 13.3 · χ² 78 / p 4e-19 | 10.6 EB05 4.8 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 8.2 | no trial data cached |
| Lymphoma | 11 | 11.7 6.5–21.1ROR 11.8 · χ² 97 / p 3e-23 | 9.8 EB05 5.2 · IC025 +2.0 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 7.3 | no trial data cached |
| Malignant neoplasm progression | 72 | 11.7 9.3–14.6ROR 12.3 · χ² 694 / p 3e-153 | 11.5 EB05 9.3 · IC025 +3.0 3/3 methods agree | Reporting / coding artifact | serious PRR 7.4 · 100% clinician | no trial data cached |
| Delirium | 23 | 11.0 7.3–16.5ROR 11.2 · χ² 199 / p 2e-45 | 10.1 EB05 6.8 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious PRR 6.9 · 96% clinician | no trial data cached |
| Lymphopenia | 9 | 10.6 5.5–20.2ROR 10.6 · χ² 69 / p 6e-17 | 8.2 EB05 4.2 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 7.1 | no trial data cached |
| Metastases to central nervous system | 7 | 9.0 4.3–18.9ROR 9.1 · χ² 42 / p 4e-11 | 6.4 EB05 3.1 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 5.6 | no trial data cached |
| Altered state of consciousness | 10 | 7.7 4.1–14.2ROR 7.7 · χ² 51 / p 4e-13 | 6.0 EB05 3.4 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 4.8 | no trial data cached |
| Neurotoxicity | 8 | 7.6 3.8–15.2ROR 7.6 · χ² 39 / p 2e-10 | 5.6 EB05 3.0 · IC025 +1.2 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 4.8 | no trial data cached |
| Full blood count decreased | 9 | 7.4 3.8–14.1ROR 7.4 · χ² 43 / p 2e-11 | 5.6 EB05 3.1 · IC025 +1.3 3/3 methods agree | Lab value / disease marker | serious PRR 6.6 | no trial data cached |
| Myelodysplastic syndrome | 6 | 6.8 3.1–15.2ROR 6.9 · χ² 24 / p 4e-7 | 4.8 EB05 2.4 · IC025 +0.8 3/3 methods agree | Not in label — unassessed | serious PRR 4.3 | no trial data cached |
| Intercepted product preparation error | 5 | 6.8 2.8–16.2ROR 6.8 · χ² 19 / p 6e-6 | 4.5 EB05 2.1 · IC025 +0.6 3/3 methods agree | Not in label — unassessed | serious n=1 | no trial data cached |
| Myelosuppression | 9 | 4.4 2.3–8.4ROR 4.4 · χ² 20 / p 4e-6 | 3.7 EB05 2.1 · IC025 +0.8 3/3 methods agree | Not in label — unassessed | serious PRR 2.7 | no trial data cached |
| Injection site rash | 6 | 3.3 1.5–7.2ROR 3.3 · χ² 7 / p 0.003 | 2.8 EB05 1.4 · IC025 +0.1 | Labeled adverse reaction exact term | serious n=3 | no trial data cached |
| Injection site reaction | 13 | 3.1 1.8–5.4ROR 3.1 · χ² 17 / p 2e-5 | 2.9 EB05 1.8 · IC025 +0.6 | Labeled adverse reaction exact term | serious PRR 7.7 | no trial data cached |
Trial evidence (ClinicalTrials.gov)
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 |
|---|---|---|---|---|---|---|
| Cytokine release syndrome | 450 | 398.8 369.8–430.2ROR 616.6 · χ² 174,070 / p <1e-300 | 382.9 EB05 354.2 · IC025 +7.9 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 242.7 · 99% clinician | no trial data cached |
| Malignant neoplasm progression | 72 | 11.7 9.3–14.6ROR 12.3 · χ² 694 / p 3e-153 | 11.5 EB05 9.3 · IC025 +3.0 3/3 methods agree | Reporting / coding artifact | serious PRR 7.4 · 100% clinician | no trial data cached |
| Neutrophil count decreased | 55 | 22.4 17.3–29.0ROR 23.4 · χ² 1,104 / p 2e-242 | 22.2 EB05 17.7 · IC025 +3.8 3/3 methods agree | Labeled (related wording) related wording | serious PRR 15.5 · 100% clinician | no trial data cached |
| Cytomegalovirus infection | 36 | 35.8 25.9–49.4ROR 36.8 · χ² 1,180 / p 7e-259 | 35.1 EB05 26.5 · IC025 +4.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 21.1 · 100% clinician | no trial data cached |
| Blood lactate dehydrogenase increased | 24 | 24.8 16.7–36.9ROR 25.3 · χ² 525 / p 2e-116 | 24.4 EB05 17.2 · IC025 +3.4 3/3 methods agree | Lab value / disease marker | serious PRR 15.0 · 100% clinician | no trial data cached |
| Delirium | 23 | 11.0 7.3–16.5ROR 11.2 · χ² 199 / p 2e-45 | 10.1 EB05 6.8 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious PRR 6.9 · 96% clinician | no trial data cached |
| Injection site reaction | 13 | 3.1 1.8–5.4ROR 3.1 · χ² 17 / p 2e-5 | 2.9 EB05 1.8 · IC025 +0.6 | Labeled adverse reaction exact term | serious PRR 7.7 | no trial data cached |
| Covid-19 pneumonia | 13 | 18.0 10.5–31.0ROR 18.2 · χ² 192 / p 5e-44 | 17.2 EB05 10.0 · IC025 +2.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 11.3 | no trial data cached |
| Lymphoma | 11 | 11.7 6.5–21.1ROR 11.8 · χ² 97 / p 3e-23 | 9.8 EB05 5.2 · IC025 +2.0 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 7.3 | no trial data cached |
| Altered state of consciousness | 10 | 7.7 4.1–14.2ROR 7.7 · χ² 51 / p 4e-13 | 6.0 EB05 3.4 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 4.8 | no trial data cached |
| Bacteraemia | 10 | 14.0 7.6–26.0ROR 14.1 · χ² 108 / p 1e-25 | 12.2 EB05 6.1 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 8.8 | no trial data cached |
| Intestinal perforation | 10 | 14.7 7.9–27.2ROR 14.8 · χ² 114 / p 6e-27 | 12.9 EB05 6.4 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 9.1 | no trial data cached |
| Myelosuppression | 9 | 4.4 2.3–8.4ROR 4.4 · χ² 20 / p 4e-6 | 3.7 EB05 2.1 · IC025 +0.8 3/3 methods agree | Not in label — unassessed | serious PRR 2.7 | no trial data cached |
| Full blood count decreased | 9 | 7.4 3.8–14.1ROR 7.4 · χ² 43 / p 2e-11 | 5.6 EB05 3.1 · IC025 +1.3 3/3 methods agree | Lab value / disease marker | serious PRR 6.6 | no trial data cached |
| Lymphopenia | 9 | 10.6 5.5–20.2ROR 10.6 · χ² 69 / p 6e-17 | 8.2 EB05 4.2 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 7.1 | 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.
- Delirium — n=23, PRR 11.0
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 Epcoritamab-Bysp?
In FDA FAERS, the most frequently co-reported reaction terms for Epcoritamab-Bysp are cytokine release syndrome, neutrophil count decreased, cytomegalovirus infection, blood lactate dehydrogenase increased, delirium, injection site reaction. 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 Epcoritamab-Bysp have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: CYTOKINE RELEASE SYNDROME AND IMMUNE EFFECTOR CELL-ASSOCIATED NEUROTOXICITY SYNDROME Cytokine release syndrome (CRS), including serious or fatal reactions, can occur in patients receiving EPKINLY. Initiate treatment with the EPKINLY step-up dosage schedule to reduce the incidence and severity of CRS.
Do FAERS signals prove that Epcoritamab-Bysp 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 d7836711-b677-412d-bf2d-0f7c8444103a, effective 20260622; matched on
openfda.generic_name.exact:"EPCORITAMAB-BYSP") - 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, 23 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.