Talimogene laherparepvec (T-VEC) is a type of immunotherapy. It is also called Imlygic.
It's a treatment for melanoma skin cancer that has spread to other areas of the skin, soft tissue or the lymph nodes, and can’t be removed with surgery.
How T-VEC works
T-VEC is a treatment using a weakened form of the cold sore virus. The changed virus grows in the cancer cells and destroys them. It also works by helping the immune system recognise and attack cancer cells.
How you have T-VEC
You have T-VEC as an injection directly into the cancer.
Before the injection, you might have a cream to numb the area (local anaesthetic). Sometimes you can have anaesthetic as an injection.
If you need T-VEC into a lymph node, your doctor or surgeon might use an ultrasound scan to help guide the needle if they can’t see or feel the node.
You might have one or several injections depending on the number of areas of melanoma you have. After the injection your doctor presses on the site for about 30 seconds. They clean the area and cover it with a dressing.
The dressing stays on for a week. Or longer if the injection site is weeping or oozing.
When you have T-VEC
After the first injection of T-VEC, you go back 3 weeks later for the second. You then have injections every 2 weeks.
You have T-VEC for at least 6 months. Your doctor may stop T-VEC if it’s no longer helping you or the side effects are too bad.
You might have blood tests before starting treatment and during your treatment. They check your general health and might check your levels of blood cells and other substances in the blood.
How often and how severe the side effects are can vary from person to person. They also depend on what other treatment you are having.
When to contact your team
Your doctor, pharmacist or nurse will go through the possible side effects. They will monitor you closely during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:
- you have severe side effects
- your side effects aren’t getting any better
- your side effects are getting worse
Early treatment can help manage side effects better.
We haven't listed all the side effects here. Remember it is very unlikely that you will have all of these side effects, but you might have some of them at the same time.
Common side effects
These side effects happen in more than 10 in 100 (10%). You might have one or more of them. They include:
These may include a high temperature, headaches, chills, muscle aches (myalgia), shivering, and feeling tired and weak.
You might have a reaction to T-VEC at the injection site. This can make the area painful, red, bleed, swell, and may feel warm. It can also cause a discharge or leakage of fluid from the site.
About 9 out of 10 (90%) people having T-VEC get flu-like symptoms. These symptoms usually get better after 3 days.
Swollen hands and feet
Swelling of hands and feet is due to fluid build up. This is called oedema. Let your doctor or nurse know if you have any swelling.
Tell your healthcare team if you keep getting headaches. They can give you painkillers to help.
Tell your doctor or nurse if you get a cough. It could be a sign of infection.
Feeling or being sick
Feeling or being sick is usually well controlled with anti sickness medicines. Avoiding fatty or fried foods, eating small meals and snacks, drinking plenty of water, and relaxation techniques can all help.
It is important to take anti sickness medicines as prescribed even if you don’t feel sick. It is easier to prevent sickness rather than treating it once it has started.
Diarrhoea or constipation
Tell your healthcare team if you have diarrhoea or constipation. They can give you medicine to help.
You might feel pain in your muscles, joints, hands, feet, arms or legs,
Less commonly you might have pain from your tumour, ear, tummy (abdomen), back of the throat, back, groin or armpit.
Speak to your doctor or nurse about what painkillers you can take to help with this.
Tiredness and weakness
You might feel very tired and as though you lack energy.
Various things can help you to reduce tiredness and cope with it, for example exercise. Some research has shown that taking gentle exercise can give you more energy. It is important to balance exercise with resting.
Occasional side effects
These side effects happen in between 1 and 10 out of every 100 people (1 to 10%). You might have one or more of them. They include:
- red, hot, swollen and tender skin caused by infection (cellulitis)
- cold sores (herpes)
- infection – this includes infection of the tumour, your upper respiratory tract (throat, sinuses and voice box), and rarely the area where the needle went in
- a low number of red blood cells (anaemia) – you might feel tired and lack energy
- a reaction by your immune system causing inflammation, such as, inflammation of your lungs or kidneys, your blood vessels becoming narrow or block (vasculitis) or worsening of skin conditions (psoriasis and vitiligo)
- lack of fluid in your body (dehydration) – you might feel thirsty, dizzy, confused, have a very dry mouth, your urine might be dark or you may not be going very much
- feeling confused, anxious or low in mood (depression)
- difficulty in sleeping (insomnia)
- fast heart rate
- high blood pressure
- flushing of the skin
- shortness of breath
- skin problems – your skin might have patchy white areas (vitiligo), or a rash that could be itchy, red, sore, swollen and blister
- generally feeling unwell
- losing weight
- wound problems such as bruising, pain, ooze or discharge
- blood clots that are life threatening: signs are pain, swelling and redness where the clot is. Feeling breathless can be a sign of a blood clot on the lung. Contact your advice line or doctor straight away if you have any of these symptoms
Rare side effects
These side effects happen in fewer than 1 in 100 people (1%). You might have one or more of them. They include:
- cancerous white blood cells near or at the injection site (plasmacytoma)
- an allergic reaction - you may get a rash, shortness of breath, redness or swelling of the face
- herpes eye infection (keratitis herpes)
- difficulty breathing due to narrowing or blocked airways
Coping with side effects
We have more information about side effects and tips on how to cope with them.
What else do I need to know?
Other medicines, foods and drink
Cancer drugs can interact with some other medicines and herbal products. Tell your doctor or pharmacist about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies.
Driving and use of machinery
This drug can cause tiredness, dizziness and eye problems. Don’t drive or operate heavy machinery if you have these problems.
It is not known whether this treatment affects fertility in people. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.
Pregnancy and contraception
It is unknown whether treatment may or may not harm a baby developing in the womb. It is important not to become pregnant or father a child while you are having treatment.
Talk to your doctor or nurse about effective contraception you can use during treatment. Ask how long you should use it before starting treatment and after treatment has finished.
Doctors recommend that you use a condom while on treatment in case the drug can be passed on during sexual contact.
It is not known whether this drug comes through into the breast milk. Doctors usually advise that you don’t breastfeed during this treatment.
Treatment for other conditions
Always tell other doctors, nurses, pharmacists or dentists that you’re having this treatment if you need treatment for anything else, including teeth problems.
Don’t have immunisations with live vaccines while you’re having treatment and for up to 12 months afterwards. The length of time depends on the treatment you are having. Ask your doctor or pharmacist how long you should avoid live vaccinations.
In the UK, live vaccines include rubella, mumps, measles, BCG, yellow fever and one of the shingles vaccines called Zostavax.
You can have:
- other vaccines, but they might not give you as much protection as usual
- the flu vaccine (as an injection)
- the coronavirus (COVID-19) vaccine - talk to your doctor or pharmacist about the best time to have it in relation to your cancer treatment
Members of your household who are aged 5 years or over are also able to have the COVID-19 vaccine. This is to help lower your risk of getting COVID-19 while having cancer treatment and until your
Contact with others who have had immunisations - You can be in contact with other people who have had live vaccines as injections. Avoid close contact with people who have recently had live vaccines taken by mouth (oral vaccines) such as the oral typhoid vaccine. Sometimes people who have had the live shingles vaccine can get a shingles type rash. If this happens they should keep the area covered.
If your immune system is severely weakened, you should avoid contact with children who have had the flu vaccine as a nasal spray as this is a live vaccine. This is for 2 weeks following their vaccination.
Babies have the live rotavirus vaccine. The virus is in the baby’s poo for about 2 weeks and could make you ill if your immunity is low. Get someone else to change their nappies during this time if you can. If this isn't possible, wash your hands well after changing their nappy.
More information about this treatment
For further information about this treatment go to the electronic Medicines Compendium (eMC) website.
You can report any side effect you have to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.
This page is due for review. We will update this as soon as possible.