Talimogene Laherparepvec side effects: what 1,577 FDA adverse event reports show

Talimogene Laherparepvec · Imlygic · 26 reaction terms · 847 drug–reaction co-reports · data 2026-09-14

Drug class

Genetically modified oncolytic viral therapy

FDA label, Indications wording

Brand names

Imlygic

openFDA label

Who reports

1,577 reports · 55% serious · 189 with death outcome · 47% female

openFDA FAERS counts, all years, deduplication not applied

Used for

IMLYGIC is a genetically modified oncolytic viral therapy indicated for the local treatment of unresectable cutaneous, subcutaneous, and nodal lesions in patients with melanoma recurrent after initial surgery. Limitations of use : IMLYGIC has not been shown to improve overall survival or have an effect on visceral metastases.

FDA label, Indications and Usage

What it is

IMLYGIC (talimogene laherparepvec) is a sterile suspension for intralesional injection. IMLYGIC is a live, attenuated HSV-1 that has been genetically modified to express huGM-CSF. The parental.

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 18 strongest signals

Labeled adverse reaction 3Labeled (related wording) 6Likely indication confounding 1Reporting / coding artifact 4Not in label — unassessed 4

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.
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. 8 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
Malignant melanoma	68	67.7 53.6–85.5ROR 70.7 · χ² 4,385 / p <1e-300	66.2 EB05 54.0 · IC025 +5.1 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious PRR 71.0 · 100% clinician	no trial data cached
Therapy partial responder	60	53.2 41.5–68.2ROR 55.2 · χ² 3,010 / p <1e-300	52.1 EB05 42.0 · IC025 +4.8 3/3 methods agree	Reporting / coding artifact	serious PRR 60.0 · 100% clinician	no trial data cached
Circumstance or information capable of leading to medication error	89	35.4 28.9–43.3ROR 37.4 · χ² 2,934 / p <1e-300	35.0 EB05 29.3 · IC025 +4.5 3/3 methods agree	Not in label — unassessed	–	no trial data cached
Oral herpes	47	32.2 24.3–42.7ROR 33.2 · χ² 1,388 / p <1e-300	31.8 EB05 24.8 · IC025 +4.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 13.3 · ♀ 81% (drug 47%) · 100% clinician	no trial data cached
Product storage error	134	20.6 17.5–24.3ROR 22.4 · χ² 2,489 / p <1e-300	20.5 EB05 17.8 · IC025 +4.0 3/3 methods agree	Reporting / coding artifact	–	no trial data cached
Metastases to central nervous system	16	16.6 10.2–27.1ROR 16.8 · χ² 219 / p 6e-50	15.9 EB05 9.9 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 17.4	no trial data cached
Therapy non-responder	51	15.2 11.6–20.0ROR 15.7 · χ² 665 / p 8e-147	15.1 EB05 11.8 · IC025 +3.3 3/3 methods agree	Reporting / coding artifact	serious PRR 8.6 · 96% clinician	no trial data cached
Influenza like illness (flu-like illness)	84	13.5 11.0–16.7ROR 14.2 · χ² 965 / p 4e-212	13.4 EB05 11.1 · IC025 +3.3 3/3 methods agree	Labeled (related wording) related wording	serious PRR 23.6 · 98% clinician	no trial data cached
Metastases to lung	10	11.5 6.2–21.4ROR 11.6 · χ² 86 / p 1e-20	9.4 EB05 4.9 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 12.1	no trial data cached
Chills	73	8.3 6.6–10.3ROR 8.6 · χ² 462 / p 1e-102	8.0 EB05 6.5 · IC025 +2.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.3 · 95% clinician	no trial data cached
Drug effective for unapproved indication	17	7.7 4.8–12.4ROR 7.8 · χ² 93 / p 2e-22	6.6 EB05 4.3 · IC025 +1.9 3/3 methods agree	Labeled (related wording) related wording	serious n=12	no trial data cached
Cytokine release syndrome	10	7.0 3.8–13.0ROR 7.0 · χ² 45 / p 8e-12	5.5 EB05 3.2 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 7.3	no trial data cached
Skin cancer	11	6.8 3.8–12.2ROR 6.8 · χ² 49 / p 1e-12	5.5 EB05 3.2 · IC025 +1.4 3/3 methods agree	Labeled (related wording) related wording	serious PRR 7.2	no trial data cached
Accidental exposure to product	32	4.3 3.0–6.0ROR 4.3 · χ² 77 / p 9e-19	4.0 EB05 3.0 · IC025 +1.4 3/3 methods agree	Reporting / coding artifact	serious PRR 1.6 · ♀ 68% (drug 47%) · 100% clinician	no trial data cached
Injection site haemorrhage	15	2.5 1.5–4.2ROR 2.5 · χ² 12 / p 2e-4	2.4 EB05 1.6 · IC025 +0.4	Labeled (related wording) related wording	serious PRR 6.5	no trial data cached
Injection site erythema (redness where injected)	22	2.4 1.6–3.6ROR 2.4 · χ² 16 / p 3e-5	2.3 EB05 1.6 · IC025 +0.5	Labeled (related wording) related wording	serious PRR 5.5 · 100% clinician	no trial data cached
Injection site pruritus	11	2.2 1.2–4.0ROR 2.2 · χ² 6 / p 0.007	2.1 EB05 1.3 · IC025 +0.0	Labeled (related wording) related wording	serious PRR 5.9	no trial data cached
Injection site pain (pain where injected)	49	2.1 1.6–2.8ROR 2.2 · χ² 29 / p 3e-8	2.1 EB05 1.7 · IC025 +0.6	Labeled adverse reaction exact term	serious PRR 6.4	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	134	20.6 17.5–24.3ROR 22.4 · χ² 2,489 / p <1e-300	20.5 EB05 17.8 · IC025 +4.0 3/3 methods agree	Reporting / coding artifact	–	no trial data cached
Circumstance or information capable of leading to medication error	89	35.4 28.9–43.3ROR 37.4 · χ² 2,934 / p <1e-300	35.0 EB05 29.3 · IC025 +4.5 3/3 methods agree	Not in label — unassessed	–	no trial data cached
Influenza like illness (flu-like illness)	84	13.5 11.0–16.7ROR 14.2 · χ² 965 / p 4e-212	13.4 EB05 11.1 · IC025 +3.3 3/3 methods agree	Labeled (related wording) related wording	serious PRR 23.6 · 98% clinician	no trial data cached
Chills	73	8.3 6.6–10.3ROR 8.6 · χ² 462 / p 1e-102	8.0 EB05 6.5 · IC025 +2.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.3 · 95% clinician	no trial data cached
Malignant melanoma	68	67.7 53.6–85.5ROR 70.7 · χ² 4,385 / p <1e-300	66.2 EB05 54.0 · IC025 +5.1 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious PRR 71.0 · 100% clinician	no trial data cached
Therapy partial responder	60	53.2 41.5–68.2ROR 55.2 · χ² 3,010 / p <1e-300	52.1 EB05 42.0 · IC025 +4.8 3/3 methods agree	Reporting / coding artifact	serious PRR 60.0 · 100% clinician	no trial data cached
Therapy non-responder	51	15.2 11.6–20.0ROR 15.7 · χ² 665 / p 8e-147	15.1 EB05 11.8 · IC025 +3.3 3/3 methods agree	Reporting / coding artifact	serious PRR 8.6 · 96% clinician	no trial data cached
Injection site pain (pain where injected)	49	2.1 1.6–2.8ROR 2.2 · χ² 29 / p 3e-8	2.1 EB05 1.7 · IC025 +0.6	Labeled adverse reaction exact term	serious PRR 6.4	no trial data cached
Oral herpes	47	32.2 24.3–42.7ROR 33.2 · χ² 1,388 / p <1e-300	31.8 EB05 24.8 · IC025 +4.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 13.3 · ♀ 81% (drug 47%) · 100% clinician	no trial data cached
Accidental exposure to product	32	4.3 3.0–6.0ROR 4.3 · χ² 77 / p 9e-19	4.0 EB05 3.0 · IC025 +1.4 3/3 methods agree	Reporting / coding artifact	serious PRR 1.6 · ♀ 68% (drug 47%) · 100% clinician	no trial data cached
Injection site erythema (redness where injected)	22	2.4 1.6–3.6ROR 2.4 · χ² 16 / p 3e-5	2.3 EB05 1.6 · IC025 +0.5	Labeled (related wording) related wording	serious PRR 5.5 · 100% clinician	no trial data cached
Drug effective for unapproved indication	17	7.7 4.8–12.4ROR 7.8 · χ² 93 / p 2e-22	6.6 EB05 4.3 · IC025 +1.9 3/3 methods agree	Labeled (related wording) related wording	serious n=12	no trial data cached
Metastases to central nervous system	16	16.6 10.2–27.1ROR 16.8 · χ² 219 / p 6e-50	15.9 EB05 9.9 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 17.4	no trial data cached
Injection site haemorrhage	15	2.5 1.5–4.2ROR 2.5 · χ² 12 / p 2e-4	2.4 EB05 1.6 · IC025 +0.4	Labeled (related wording) related wording	serious PRR 6.5	no trial data cached
Injection site pruritus	11	2.2 1.2–4.0ROR 2.2 · χ² 6 / p 0.007	2.1 EB05 1.3 · IC025 +0.0	Labeled (related wording) related wording	serious PRR 5.9	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.

Circumstance or information capable of leading to medication error — n=89, PRR 35.4

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 Talimogene Laherparepvec?

In FDA FAERS, the most frequently co-reported reaction terms for Talimogene Laherparepvec are circumstance or information capable of leading to medication error, influenza like illness, chills, malignant melanoma, injection site pain, oral herpes. 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 Talimogene Laherparepvec have an FDA boxed warning?

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

Do FAERS signals prove that Talimogene Laherparepvec 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 64ffb680-ea8c-42fc-9649-9e8c0eb77ddb, effective 20250404; matched on openfda.generic_name.exact:"TALIMOGENE LAHERPAREPVEC")
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, 26 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.