What the label lists and what reports show
Talimogene laherparepvec side effects
Talimogene laherparepvec's FDA label: “The most commonly reported adverse drug reactions (≥ 25%) in IMLYGIC-treated patients were fatigue, chills, pyrexia, nausea, influenza-like illness, and injection site pain.” FAERS holds 1,577 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is pyrexia (144 reports).
- No generic listed
Check it at the source: the talimogene laherparepvec FDA label on DailyMed (effective April 4, 2025); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are possible side effects of IMLYGIC?The most common side effects of IMLYGIC include: Tiredness Chills Fever Nausea Flu-like symptoms Pain at treatment site Tell your doctor right away if you get any of the signs and symptoms of herpes infection, including but not limited to: Pain, burning, tingling, or blister formation around the mouth, genitals, or any part of the body, near or far from the injection site Eye pain, light sensitivity, discharge from the eyes, or blurry vision Weakness in arms or legs Extreme drowsiness (feeling sleepy) Mental confusion If you think you have a herpes infection, inform your healthcare provider. Life threatening-herpes infection and herpes infection spreading to any part of the body far from the injection site (disseminated herpetic infection) may occur in patients treated with IMLYGIC. If you have any new or worsening symptoms, call your healthcare provider right away. […]
Source: FDA drug label, Amgen Inc, effective April 4, 2025 (SPL set 64ffb680-ea8c-42fc-9649-9e8c0eb77ddb), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most commonly reported adverse drug reactions (≥ 25%) in IMLYGIC-treated patients were fatigue, chills, pyrexia, nausea, influenza-like illness, and injection site pain.
From the label: adverse reactions, continuedThe most commonly reported adverse drug reactions (≥ 25%) in IMLYGIC-treated patients were fatigue, chills, pyrexia, nausea, influenza-like illness, and injection site pain. The following adverse reactions are discussed in greater detail in another section of the label: Herpetic Infection [see Warnings and Precautions ( 5.2 )] Injection Site Complications [see Warnings and Precautions ( 5.3 )] The most commonly reported adverse drug reactions (≥ 25%) in IMLYGIC-treated patients were fatigue, chills, pyrexia, nausea, influenza-like illness, and injection site pain. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Amgen at 1-855-IMLYGIC (1-855-465-9442) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of IMLYGIC was evaluated in 419 patients who received at least 1 dose of either IMLYGIC (n = 292) or subcutaneously administered granulocyte-macrophage colony-stimulating factor (GM-CSF) (n = 127) in an open-label, randomized clinical study of patients with stage IIIB, IIIC, and IV melanoma that was not considered to be surgically resectable [see Clinical Studies ( 14 )]. …
Source: FDA drug label, Amgen Inc, effective April 4, 2025 (SPL set 64ffb680-ea8c-42fc-9649-9e8c0eb77ddb), via openFDA; the full label on DailyMed
What do FAERS reports show?
1,577 reports list talimogene laherparepvec among the medicines taken, each a report of something that happened, not proof the medicine caused it; 189 are coded as a death and 301 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 19 reactions below, 9 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Talimogene laherparepvec: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions