Drug · FAERS side-effect profile with label screen

Efgartigimod Alfa and Hyaluronidase (Human Recombinant) side effects: what 427 FDA adverse event reports show

Efgartigimod Alfa And Hyaluronidase (Human Recombinant) · Vyvgart · 17 reaction terms · 169 drug–reaction co-reports · data 2026-09-14

Drug class

Neonatal Fc Receptor Blocker

FDA label (Established Pharmacologic Class) · compare the class

Brand names

Vyvgart

openFDA label

Who reports

427 reports · 89% serious · 19 with death outcome · 50% female

openFDA FAERS counts, all years, deduplication not applied

Used for

VYVGART is indicated for the treatment of adult patients with generalized myasthenia gravis (gMG). VYVGART is a neonatal Fc receptor blocker indicated for the treatment of adult patients with generalized myasthenia gravis (gMG). ( 1 )

FDA label, Indications and Usage

What it is

Efgartigimod alfa-fcab is a human immunoglobulin G1 (IgG1) -derived Fc fragment (fragment, crystallized) of the za allotype. The efgartigimod alfa-fcab Fc fragment is a homodimer consisting of.

FDA label, Description section

Boxed warning

None in the current 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 13 strongest signals

Labeled (related wording) 1Reporting / coding artifact 4Not in label — unassessed 8

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.
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. 4 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	20	102.1 66.5–156.6ROR 107.0 · χ² 1,899 / p <1e-300	93.0 EB05 63.6 · IC025 +4.1 3/3 methods agree	Reporting / coding artifact	serious n=19	no trial data cached
Eyelid ptosis	15	72.5 44.1–119.3ROR 75.1 · χ² 987 / p 7e-217	66.6 EB05 42.8 · IC025 +3.6 3/3 methods agree	Not in label — unassessed	serious n=14	no trial data cached
Choking	14	35.4 21.2–59.3ROR 36.6 · χ² 435 / p 8e-97	33.9 EB05 21.5 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 27.1	no trial data cached
Temperature intolerance	5	24.1 10.1–57.5ROR 24.3 · χ² 89 / p 2e-21	19.9 EB05 6.5 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious n=5	no trial data cached
Poor venous access	5	23.8 10.0–56.9ROR 24.1 · χ² 88 / p 4e-21	19.7 EB05 6.4 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious n=3	no trial data cached
Insurance issue	7	23.1 11.1–48.3ROR 23.5 · χ² 127 / p 9e-30	20.9 EB05 9.3 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 26.6	no trial data cached
Injection site rash	13	21.0 12.3–35.9ROR 21.7 · χ² 229 / p 5e-52	20.3 EB05 12.2 · IC025 +2.7 3/3 methods agree	Labeled (related wording) related wording	serious n=8	no trial data cached
Drug effect less than expected	6	20.9 9.4–46.3ROR 21.2 · χ² 95 / p 1e-22	17.8 EB05 6.6 · IC025 +1.6 3/3 methods agree	Reporting / coding artifact	serious n=6	no trial data cached
Therapeutic response shortened	12	18.5 10.6–32.4ROR 19.0 · χ² 182 / p 9e-42	17.6 EB05 10.0 · IC025 +2.5 3/3 methods agree	Reporting / coding artifact	serious PRR 29.5	no trial data cached
Injection site pruritus	13	9.6 5.6–16.4ROR 9.9 · χ² 92 / p 4e-22	8.0 EB05 4.7 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 33.8	no trial data cached
Injection site bruising	15	9.3 5.7–15.4ROR 9.6 · χ² 104 / p 1e-24	8.0 EB05 4.9 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 19.6	no trial data cached
Injection site erythema (redness where injected)	23	9.2 6.1–13.6ROR 9.6 · χ² 160 / p 6e-37	8.2 EB05 5.6 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 28.5 · 91% consumer	no trial data cached
Device difficult to use	7	5.2 2.5–10.8ROR 5.3 · χ² 20 / p 4e-6	4.0 EB05 2.1 · IC025 +0.7 3/3 methods agree	Reporting / coding artifact	serious PRR 3.9	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
Injection site erythema (redness where injected)	23	9.2 6.1–13.6ROR 9.6 · χ² 160 / p 6e-37	8.2 EB05 5.6 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 28.5 · 91% consumer	no trial data cached
Therapy change	20	102.1 66.5–156.6ROR 107.0 · χ² 1,899 / p <1e-300	93.0 EB05 63.6 · IC025 +4.1 3/3 methods agree	Reporting / coding artifact	serious n=19	no trial data cached
Injection site bruising	15	9.3 5.7–15.4ROR 9.6 · χ² 104 / p 1e-24	8.0 EB05 4.9 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 19.6	no trial data cached
Eyelid ptosis	15	72.5 44.1–119.3ROR 75.1 · χ² 987 / p 7e-217	66.6 EB05 42.8 · IC025 +3.6 3/3 methods agree	Not in label — unassessed	serious n=14	no trial data cached
Choking	14	35.4 21.2–59.3ROR 36.6 · χ² 435 / p 8e-97	33.9 EB05 21.5 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 27.1	no trial data cached
Injection site pruritus	13	9.6 5.6–16.4ROR 9.9 · χ² 92 / p 4e-22	8.0 EB05 4.7 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 33.8	no trial data cached
Injection site rash	13	21.0 12.3–35.9ROR 21.7 · χ² 229 / p 5e-52	20.3 EB05 12.2 · IC025 +2.7 3/3 methods agree	Labeled (related wording) related wording	serious n=8	no trial data cached
Therapeutic response shortened	12	18.5 10.6–32.4ROR 19.0 · χ² 182 / p 9e-42	17.6 EB05 10.0 · IC025 +2.5 3/3 methods agree	Reporting / coding artifact	serious PRR 29.5	no trial data cached
Device difficult to use	7	5.2 2.5–10.8ROR 5.3 · χ² 20 / p 4e-6	4.0 EB05 2.1 · IC025 +0.7 3/3 methods agree	Reporting / coding artifact	serious PRR 3.9	no trial data cached
Insurance issue	7	23.1 11.1–48.3ROR 23.5 · χ² 127 / p 9e-30	20.9 EB05 9.3 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 26.6	no trial data cached
Drug effect less than expected	6	20.9 9.4–46.3ROR 21.2 · χ² 95 / p 1e-22	17.8 EB05 6.6 · IC025 +1.6 3/3 methods agree	Reporting / coding artifact	serious n=6	no trial data cached
Poor venous access	5	23.8 10.0–56.9ROR 24.1 · χ² 88 / p 4e-21	19.7 EB05 6.4 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious n=3	no trial data cached
Temperature intolerance	5	24.1 10.1–57.5ROR 24.3 · χ² 89 / p 2e-21	19.9 EB05 6.5 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious n=5	no trial data cached
Needle issue	4	6.9 2.6–18.2ROR 6.9 · χ² 15 / p 7e-5	4.3 EB05 1.8 · IC025 +0.3	Not in label — unassessed	serious n=1	no trial data cached
Injection site discolouration	4	15.8 6.0–42.0ROR 16.0 · χ² 42 / p 5e-11	10.1 EB05 3.1 · IC025 +0.8 3/3 methods agree	Not in label — unassessed	serious n=4	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.

Injection site erythema — n=23, PRR 9.2

✓ A hand-written Bradford Hill causality assessment exists for this drug: Erythropoiesis-stimulating agents (darbepoetin alfa) ↔ Mortality / cardiovascular risk.

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 Efgartigimod Alfa?

In FDA FAERS, the most frequently co-reported reaction terms for Efgartigimod Alfa are injection site erythema, injection site bruising, eyelid ptosis, choking, injection site pruritus, injection site rash. 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 Efgartigimod Alfa have an FDA boxed warning?

No. The FDA label retrieved for Efgartigimod Alfa has no boxed warning; see the label's Warnings and Precautions for the recognised risks.

Do FAERS signals prove that Efgartigimod Alfa 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 8aefc8e3-26d6-4ff6-aab9-a7542927e084, effective 20260513; matched on openfda.generic_name.exact:"EFGARTIGIMOD ALFA")
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, 17 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.