Talimogene laherparepvec

Pronunciation: pronunciation varies by local usage.

Generic name: talimogene laherparepvec
Brand names: IMLYGIC
Drug class: Oncolytic viral therapy (genetically modified live attenuated herpes simplex virus type 1)
Form: Suspension for intralesional injection
Route: Intralesional injection
Legal status: Prescription-only oncolytic viral therapy medicine

Availability and supply rules vary by country

Trade names by country: United States

What talimogene laherparepvec is and how it works

Talimogene laherparepvec is a genetically modified oncolytic viral therapy (a live, attenuated herpes simplex virus type 1) that expresses human GM-CSF. It is indicated for local treatment of unresectable cutaneous, subcutaneous, and nodal lesions in patients with melanoma recurrent after initial surgery. It has not been shown to improve overall survival or affect visceral metastases. (1)

This medicine is for patients with recurrent melanoma lesions accessible by injection. It is administered by healthcare professionals only; patients never handle or store it. Special precautions are necessary to prevent viral transmission to immunocompromised or pregnant household contacts.

Mechanism of action: how talimogene laherparepvec works

Talimogene laherparepvec is a live, attenuated herpes simplex virus type 1 genetically modified to replicate within tumor cells and express human granulocyte-macrophage colony-stimulating factor (GM-CSF). It lyses tumor cells, releases tumor-derived antigens, and stimulates a systemic anti-tumor immune response. (1)

What talimogene laherparepvec is used for

Unresectable melanoma lesions

Local treatment of unresectable cutaneous, subcutaneous, and nodal lesions in patients with melanoma recurrent after initial surgery. Limitation of use: not shown to improve overall survival or to have an effect on visceral metastases. (1)

Before taking talimogene laherparepvec

Do not take / not appropriate for

Do not use if immunocompromised because of the risk of life-threatening disseminated herpetic infection. (all products) (1)
Do not use during pregnancy. (all products) (1)

Tell your clinician about

If you are pregnant, planning pregnancy, or breastfeeding.
If you have a weakened immune system or any condition that suppresses immunity.
If you are taking antiviral medicines, especially acyclovir, valacyclovir, or famciclovir.
If any household member or close contact is immunocompromised or pregnant.
If you have lesions near major airways that could cause breathing difficulty.
About all other medicines, vaccines, and medical conditions.

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How to take talimogene laherparepvec

Imlygic is injected directly into lesions (intralesionally) by a trained healthcare professional only. Patients never self-administer or handle the product.
The initial dose is up to 4 mL of a 10⁶ PFU/mL concentration. The second dose is given 3 weeks later, and subsequent doses every 2 weeks thereafter, all at up to 4 mL of a 10⁸ PFU/mL concentration. The total volume injected per visit must not exceed 4 mL.
Injection sites must be kept covered with an occlusive dressing for at least the first week after each treatment visit to reduce the risk of viral transmission to household contacts.
Do not ask to change the dose or schedule yourself. Any adjustment must be made by the oncology team.

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Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1)

Missed dose

Contact the treating oncology team for rescheduling instructions. Do not receive extra injections or alter the treatment interval yourself.

Overdose

If you think an incorrect dose or number of injections may have been given, contact the prescribing oncology team or emergency services immediately. Signs of systemic viral dissemination (e.g., fever, new lesions, confusion) require urgent medical assessment. (1)

Side effects

Common side effects are flu-like symptoms and injection-site reactions. Serious risks include disseminated herpetic infection in immunocompromised patients, immune-mediated events, and injection-site complications.

Fatigue

What to notice: Tiredness, lack of energy. Reported in about 50% of patients in clinical trials.

What to do: Tell the treatment team if it becomes severe or persistent. Do not stop treatment without medical advice. (1)

Chills

What to notice: Shivering, feeling cold. Reported in about 49% of patients.

What to do: Usually manageable. Report to the team if accompanied by high fever or other concerning symptoms. (1)

Fever

What to notice: Elevated body temperature. Reported in about 43% of patients.

What to do: Monitor temperature. Inform the team if fever is high or persistent. (1)

Nausea

What to notice: Feeling sick, upset stomach. Reported in about 36% of patients.

What to do: Discuss with the treatment team; anti-nausea measures may be recommended. (1)

Influenza-like illness

What to notice: Combination of fever, chills, muscle aches, headache, and tiredness. Reported in about 31% of patients.

What to do: These symptoms are common after treatment. Report if they are severe or do not improve. (1)

Injection-site pain

What to notice: Pain, soreness, or discomfort at the injection site. Reported in about 28% of patients.

What to do: Usually mild to moderate. Report to the team if pain is severe, worsening, or accompanied by other local changes. (1)

Injection-site complications

What to notice: Necrosis (blackening or death of tissue), ulceration (open sore), or impaired healing at injection sites.

What to do: Contact the treating oncology team promptly. These may require medical attention and dose adjustments. (1)

Immune-mediated events

What to notice: Unexplained kidney problems (e.g., changes in urination, swelling), lung problems (e.g., cough, shortness of breath), skin rashes, or signs of vasculitis.

What to do: Seek prompt medical assessment. These events (e.g., glomerulonephritis, pneumonitis) require evaluation. (1)

Plasmacytoma near injection sites

What to notice: New or changing lump near the injected area that may be related to plasma cells.

What to do: Contact the oncology team for further investigation. (1)

Breathing problems (if lesions near airways)

What to notice: New or worsening cough, wheezing, shortness of breath, or throat tightness.

What to do: Report to the team immediately. Lesions near major airways may cause obstruction and require careful monitoring. (1)

Serious warnings

Disseminated herpetic infection in immunocompromised patients — emergency

Symptoms: Fever, new blistering or ulcerating lesions anywhere on the body, confusion, visual changes, or other signs of systemic infection.

Action: Seek emergency medical attention immediately, especially if you are immunocompromised or have a weakened immune system. Let the clinician you see know you are receiving a live virus therapy. (1)

Severe immune-mediated adverse reactions — serious

Symptoms: Acute kidney injury (sudden decrease in urine output, swelling, blood in urine), pneumonitis (severe breathlessness, cough), or vasculitis (rash, joint pain, numbness).

Action: Contact your oncology team immediately. These conditions require prompt evaluation and may affect continued treatment. (1)

Viral transmission to vulnerable contacts — serious

Symptoms: Household members who are immunocompromised or pregnant are at risk if they have direct contact with injection sites, dressings, or body fluids.

Action: Keep injection sites occlusively covered for at least one week. Avoid direct skin contact with the site. Wash hands thoroughly. Inform your healthcare team if accidental exposure occurs. (1)

Interactions

Medicine or test	Effect	Action
Acyclovir, valacyclovir, famciclovir, and other antiherpetic antivirals	These antiviral medicines may reduce the effectiveness of Imlygic by interfering with the live oncolytic virus.	The oncology team will review any need for antiviral medication. Typically, antiherpetic antivirals should be avoided during Imlygic treatment unless medically necessary. (1)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

Imlygic is contraindicated during pregnancy. Women of childbearing potential must use effective contraception during treatment. A pregnancy test may be required before starting. (1)

Breastfeeding

The decision to discontinue breastfeeding or the therapy is made with the healthcare team, considering the importance of the medicine to the mother and the potential risk to the infant. (1)

Immunocompromised patients

Do not use in immunocompromised patients due to the risk of life-threatening disseminated herpetic infection. Healthcare providers who are immunocompromised should not prepare or administer Imlygic. (1)

Pediatric and adolescent

No information available in the source; safety and effectiveness have not been established in patients under 18 years of age.

Monitoring

Before starting

Confirm the diagnosis of unresectable cutaneous, subcutaneous, or nodal melanoma recurrent after initial surgery, and rule out visceral metastases.
Assess immune status; do not initiate in immunocompromised patients.
Obtain pregnancy test for women of childbearing potential.
Plan the injection schedule, lesion volumes, and total dose per visit.
Educate on the necessity of occlusive dressings and precautions for household contacts.

During treatment

Observe for adverse reactions at each visit, including injection-site complications and systemic symptoms of herpetic dissemination or immune-mediated events.
Keep injection sites covered for at least the first week after each treatment.
Monitor disease response and progression; re-evaluate if new visceral metastases develop.
Review concomitant medications, especially antivirals, at each visit.
Assess household contact safety and reinforce precautions.

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Storage

Imlygic is stored frozen at the treatment facility. Patients do not handle or store the medicine. Healthcare providers follow specific handling and disposal procedures for biohazardous materials. The product should never be refrozen after thawing.

Professional information

Clinician-facing context only. Use the current local prescribing information and institutional protocols.

United States

Indication: Unresectable melanoma lesions (cutaneous, subcutaneous, nodal) recurrent after initial surgery

Dose summary: Initial dose: up to 4 mL of 10⁶ PFU/mL intralesionally. Second dose (3 weeks later): up to 4 mL of 10⁸ PFU/mL intralesionally. Subsequent doses: every 2 weeks, up to 4 mL of 10⁸ PFU/mL. Total injection volume per visit not to exceed 4 mL. Dosing volume per lesion based on size; refer to full prescribing information.

Renal context: No dose adjustment for renal or hepatic impairment described in the source; consult specialist and full prescribing information. (1)

Mechanism of action

Hepatic guidance

No information available in source; refer to prescribing information.

Overdose note

Medication errors require immediate specialist advice. Accidental overdosage may increase local and systemic adverse reactions. Antiviral therapy (e.g., acyclovir) may be considered if clinically indicated, but may compromise therapeutic effect. (1)

Frequently asked questions

Is Imlygic a form of the herpes virus?

Yes, Imlygic is a live, weakened, genetically modified form of the herpes simplex virus type 1 (HSV-1) designed to multiply in tumor tissue and stimulate an immune response against the cancer. Because it is a live virus, household members who are pregnant or immunocompromised must avoid contact with injection-site dressings, and the sites need to stay covered for at least a week after each treatment visit. (1)

Can Imlygic cure melanoma that has spread internally?

No. The prescribing information states that Imlygic has not been shown to improve overall survival or to have an effect on melanoma that has spread to internal organs (visceral metastases). It is a local treatment for skin and lymph-node lesions. (1)

Can I take antiviral tablets like acyclovir during treatment?

Antiherpetic antivirals like acyclovir can reduce the effectiveness of Imlygic. The oncology team will consider any need for antiviral medication and usually recommends avoiding them during treatment. (1)

What symptoms are common after injections?

Flu-like effects are very common, including fatigue, chills, fever, nausea, and injection-site pain. These are usually manageable, but you should tell your treatment team if they are severe or persistent. (1)

What is the mechanism of action of talimogene laherparepvec?

What is the generic name of Talimogene laherparepvec?

The generic name is talimogene laherparepvec. It is sold under brand names including IMLYGIC. (1)

What class of drug is talimogene laherparepvec?

Talimogene laherparepvec is classed as: Oncolytic viral therapy (genetically modified live attenuated herpes simplex virus type 1). (1)

References

IMLYGIC (talimogene laherparepvec) suspension for intralesional injection — prescribing informationDailyMed, U.S. National Library of Medicine · United States · dated 2024-11 · accessed 2026-08-08 · source 1
Talimogene Laherparepvec Injection — patient drug information (MedlinePlus)U.S. National Library of Medicine (MedlinePlus) · US · accessed 2026-08-14 · source 2
Imlygic — FDA approval record (Drugs@FDA BLA125518)U.S. Food and Drug Administration · US · accessed 2026-08-14 · source 3
talimogene laherparepvec — RxNorm normalized drug concept (RXCUI 1721264)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 4

Brand names by country

Single-ingredient talimogene laherparepvec names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

Imlygic100000000 [PFU]/mL, 1000000 [PFU]/mL · amgen inc

View brands in additional countries.