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Generic name: talimogene laherparepvectal-IM-oh-jeen-la-HER-pa-REP-vek ]
Drug class: Miscellaneous antineoplastics

Medically reviewed by Philip Thornton, DipPharm. Last updated on Jul 26, 2022.

What is Imlygic?

Imlygic is a cancer medicine that affects the actions of the body's immune system, helping the body produce an "antitumor" response.

Imlygic is a genetically modified weak form of type 1 herpes simplex virus (the virus that causes common cold sores).

Imlygic is used to treat a type of cancer called melanoma when it is on the skin or in the lymph glands.


Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Before taking this medicine

Accidental exposure to the virus in Imlygic may cause you to develop symptoms of herpes virus infection. However, not treating melanoma can allow the cancer to progress and spread to other parts of the body. Melanoma is difficult to treat after it progresses, and this type of cancer can be fatal. Talk to your doctor about the risks and benefits of using Imlygic.

You should not be treated with Imlygic if you are allergic to talimogene laherparepvec, or if:

  • you have a weak immune system (caused by disease or by using certain medicine); or

  • you are pregnant.

To make sure Imlygic is safe for you, tell your doctor if you have:

  • cold sores or genital herpes;

  • blood cancer (leukemia);

  • bone marrow cancer (myeloma);

  • HIV or AIDS; or

  • an autoimmune disorder such as rheumatoid arthritis, lupus, or psoriasis.

Tell your doctor if anyone in your household is pregnant or has a weak immune system.

Talimogene laherparepvec can harm an unborn baby or cause birth defects. Do not use Imlygic if you are pregnant, and tell your doctor right away if you become pregnant. If you develop symptoms of herpes virus infection while using Imlygic, the virus could be passed to your baby during childbirth.

Use effective birth control to prevent pregnancy while you are using Imlygic. Follow your doctor's instructions about how long to prevent pregnancy after your treatment ends.

It may not be safe to breastfeed while using Imlygic. Ask your doctor about any risk.

How is Imlygic given?

Imlygic is injected directly into a tumor on your skin, or into a lymph node under your skin. A healthcare provider will give you this injection.

Imlygic is usually given every 2 weeks or until your tumor is gone. The first two injections of Imlygic are usually given 3 weeks apart.

Your care providers will use special precautions to avoid getting this medicine on other areas of your body. If this medicine accidentally gets on your skin, wash it thoroughly with soap and warm water.

The virus contained in Imlygic is a weak form of the herpes simplex virus that can spread to other parts of your body. Carefully follow your doctor's instructions about taking care of the places on your body where Imlygic is injected.

  • For at least 1 week after your injection, keep the treatment area covered with an airtight and waterproof bandage. You may need to keep the treated area covered for longer than 1 week if it is draining or oozing.

  • Change your dressing often, to keep the treated area clean.

  • Wear latex gloves while you are cleaning the treatment area or putting on a new bandage. Place used gloves and bandages in a sealed plastic bag and throw it away in the trash.

The virus in Imlygic can also spread to other people you have close contact with. Avoid being near people who are sick or have infections. Avoid kissing anyone who has a mouth sore or cold sore (sometimes called a fever blister). Also avoid being near pregnant women.

Call your doctor if you you have any new skin lesions or signs of lymph gland tumors after you have stopped using Imlygic.

Dosing information

Usual Adult Dose of Imlygic for Melanoma - Metastatic:

Initial Dose:
-Up to 4 mL at a concentration of 10(6) [1 million] plaque-forming units (PFU) per mL by intralesional injection.
-Largest lesion(s) should be injected first.
-Remaining lesion(s) should be prioritized for injection based on lesion size.

Second Dose:
-Up to 4 mL at a concentration of 10(8) [100 million] PFU per mL by intralesional injection 3 weeks after initial treatment.
-New lesions that developed since initial treatment should be injected first.
-Remaining lesion(s) should be prioritized for injection based on lesion size.

All Subsequent Treatments (including Reinitiation):
-Up to 4 mL at a concentration of 10(8) [100 million] PFU per mL by intralesional injection 2 weeks after previous treatment.
-New lesions that developed since previous treatment should be injected first.
-Remaining lesion(s) should be prioritized for injection based on lesion size.

Maximum Dose: The total injection volume for each treatment visit should not exceed 4 mL for all injected lesions combined.

Duration of Therapy:
-At each treatment visit: Lesions should be injected until maximum injection volume is reached or until all injectable lesion(s) have been treated.
-Full treatment course: At least 6 months unless other treatment is required or until there are no injectable lesions to treat.

The injection volume should be based on lesion size (lesions clustered together should be treated as a single lesion):
-Greater than 5 cm: Up to 4 mL
-Greater than 2.5 cm to 5 cm: Up to 2 mL
-Greater than 1.5 cm to 2.5 cm: Up to 1 mL
-Greater than 0.5 cm to 1.5 cm: Up to 0.5 mL
-0.5 cm or less: Up to 0.1 mL

Use: Local treatment of unresectable cutaneous, subcutaneous, and nodal lesions in patients with melanoma recurrent after initial surgery.

What happens if I miss a dose?

Call your doctor for instructions if you miss an appointment for your injection.

What happens if I overdose?

Since Imlygic is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

What should I avoid while receiving Imlygic?

Avoid touching or scratching the areas where this medicine was injected.

The virus contained in Imlygic can pass into body fluids (urine, feces, vomit, semen). Avoid allowing your body fluids to come into contact with your hands or other surfaces that cannot be cleaned. Always use a latex condom while having sex. Caregivers should wear rubber gloves while cleaning up a patient's body fluids, handling contaminated trash or laundry or changing diapers. Wash hands before and after removing gloves. Wash soiled clothing and linens separately from other laundry.

Follow your doctor's instructions about how long you should keep using these precautions after your Imlygic treatment ends.

Imlygic side effects

Get emergency medical help if you have signs of an allergic reaction to Imlygic: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any signs that you may be developing herpes simplex virus, such as:

  • tingling, burning, or pain (especially around your mouth or genitals);

  • weakness or cramps in an arm or leg, sometimes with burning pain;

  • eye pain, crusting or drainage, blurred vision (your eyes may be more sensitive to light);

  • confusion, severe drowsiness; or

  • blisters forming on your fingers or ears, or around your mouth or genitals.

Also call your doctor if you have:

  • any skin lesion that will not heal; or

  • redness, swelling, warmth, oozing, or skin changes where the injection was given.

Common Imlygic side effects may include:

  • fever, chills, flu-like symptoms;

  • feeling tired;

  • nausea; or

  • pain where the medicine was injected.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Imlygic?

Tell your doctor about all your current medicines and any you start or stop using while being treated with Imlygic, especially:

  • medicine to treat herpes (acyclovir, valacyclovir, or others); or

  • drugs that weaken the immune system (such as cancer medicine, steroids, and medicines to prevent organ transplant rejection).

This list is not complete. Other drugs may interact with talimogene laherparepvec, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed in this medication guide.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Imlygic only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.