Cancer drugs A to Z list
Mogamulizumab is a type of immunotherapy. You pronounce it as mo-gam-u-liz-oo-mab. It is also known as poteligeo. It is a treatment for certain types of cutaneous T cell lymphoma called mycosis fungoides and Sezary syndrome. You might have mogamulizumab if you have already had at least one other treatment that is no longer working.
Read more about cutaneous T cell lymphoma
Mogamulizumab is a type of immunotherapy called a . It helps your immune system attack and destroy the lymphoma cells.
Read more about how monoclonal antibodies work
You have mogamulizumab as a drip into your bloodstream (intravenously).
You might have treatment through a long plastic tube that goes into a large vein in your chest. The tube stays in place throughout the course of treatment. This can be a:
central line
PICC line
portacath
You might have treatment through a thin short tube (a cannula) that goes into a vein in your arm. You have a new cannula each time you have treatment.
Find out more about having treatment into a vein
You have mogamulizumab as cycles of treatment. This means that you have the drug and then a rest to allow your body to recover.
Each cycle of treatment lasts 28 days (4 weeks).
You have mogamulizumab once a week for the first cycle.
You then have it once every 2 weeks from cycle 2 onwards.
You have it as a drip (infusion) over at least 60 minutes (1 hour).
You continue taking mogamulizumab for as long as it is working and you are not experiencing too many side effects.
You have blood tests before and during your treatment. They check your levels of and other substances in the blood. They also check how well your liver and kidneys are working.
Before treatment starts you may have a blood test to check for viruses such as hepatitis B, hepatitis C, and HIV. This is called a viral screen.
It’s important for your doctor to know if you have had any of these viruses. This is because this treatment can weaken your and can cause the virus to become active again (reactivation).
Side effects can vary from person to person. They also depend on what other treatment you are having.
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. Talk to your healthcare team if you have any new symptoms that you think might be a side effect of your treatment.
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.
These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:
A reaction may happen during the infusion. Symptoms can include a skin rash, itching, swelling of the lips, face or throat, breathing difficulties, fever and chills. Your nurse will give you medicines beforehand to try to prevent a reaction.
Increased risk of getting an infection is due to a drop in white blood cells. Symptoms include a change in temperature, aching muscles, cough, headaches, feeling cold and shivery, pain or a burning feeling when peeing, or generally feeling unwell. You might have other symptoms depending on where the infection is.
Mogamulizumab can cause infections of different parts of your body including a chest infection, a bladder or urinary tract infection (UTI), a skin infection or viruses you have had in the past such as herpes, or becoming active again (reactivation).
Infections can sometimes be life threatening. You should contact your advice line urgently if you think you have an infection.
Sepsis happens when your body has an overwhelming response to an infection. Symptoms can include feeling very unwell, not passing urine, slurred speech or confusion, breathlessness, mottled or discoloured skin, extreme shivering or muscle pain.
You may develop a skin rash. This can include redness, burning, itching or a stinging sensation on your skin.
Rarely in some people this reaction may become very severe. You may start to get tender red patches which leads to peeling or blistering of the skin. This might be on the skin of your body or in your mouth or on your .
You might also feel feverish and your eyes may be more sensitive to light. This is serious and could be life threatening. Tell your doctor straight away if you notice your skin becoming very sore.
Mouth sores and ulcers can be painful. It helps to keep your mouth and teeth clean, drink plenty of fluids and avoid acidic foods such as lemons. Chewing gum can help to keep your mouth moist. Tell your doctor or nurse if you have ulcers.
Tiredness and weakness (fatigue) can happen during and after treatment. Doing gentle exercises each day can keep your energy up. Don't push yourself, rest when you start to feel tired and ask others for help.
Do not drive or operate machinery if you are feeling tired.
is easier to sort out if you treat it early. Drink plenty and eat as much fresh fruit and vegetables as you can. Try to take gentle exercise, such as walking. Tell your healthcare team if you think you are constipated. They can give you a laxative if needed.
Contact your advice line if you have diarrhoea. For example, in one day you have 2 or more loose bowel movements than usual. If you have a , you might have more output than normal. Your doctor may give you anti diarrhoea medicine to take home with you after treatment.
Try to eat small meals and snacks regularly. It’s best to try to have a healthy balanced diet if you can. You don’t necessarily need to stop eating foods that contain . But if your diet is normally very high in fibre, it might help to cut back on high fibre foods such as beans, nuts, seeds, dried fruit, bran and raw vegetables.
Drink plenty to try and replace the fluid lost. Aim for 8 to 10 glasses per day.
You may have swelling in your ankles and legs due to a build up of fluid. 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.
Feeling or being sick is usually well controlled with anti sickness medicines. It might help to avoid fatty or fried foods, eat small meals and snacks and take regular sips of water. Relaxation techniques might also 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 treat it once it has started.
These side effects happen in between 1 and 10 out of every 100 people (between 1 and 10%). You might have one or more of them. They include:
breathlessness and looking pale due to a drop in
bruising, bleeding gums or nosebleeds due to a drop in
low levels of hormone (hypothyroidism) - you may feel tired or cold, gain weight, feel sad or depressed, or your voice may deepen. You will have regular blood tests to check your thyroid hormone levels
inflammation in your bowel (colitis) causing watery diarrhoea and severe tummy pain. Tell your healthcare team if this happens
sore throat, runny nose or infection of your upper
airways
liver changes - you will have regular blood tests to check your liver
These side effects happen in fewer than 1 in 100 people (less than 1%). You might have one or more of them. They include:
inflammation of the liver – hepatitis, symptoms can include yellowing of the skin or whites of the eyes (jaundice), fever, fatigue, abdominal pain and dark urine.
changes to the levels of chemicals in your blood due to the breakdown of tumour cells (tumour lysis syndrome). You have regular blood tests to check for this
heart problems - symptoms can include chest pain, shortness of breath, feeling faint or a fast or slow heartbeat. Call 999 if you have any chest pain or shortness of breath
We have more information about side effects and tips on how to cope with them.
Cancer drugs can interact with medicines, herbal products, and some food and drinks. We are unable to list all the possible interactions that may happen. An example is grapefruit or grapefruit juice which can increase the side effects of certain drugs.
Tell your healthcare team about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies. Also let them know about any other medical conditions or allergies you may have.
It is not known whether this treatment affects in people. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.
This drug may harm a baby developing in the womb. It is important not to become pregnant or get someone pregnant while you are having treatment with this drug and for at least 6 months after treatment.
Talk to your doctor or nurse about effective contraception before starting treatment. Let them know straight away if you or your partner become pregnant while having treatment.
It is not known whether this drug comes through into the breast milk. Doctors usually advise that you don’t breastfeed during this treatment.
If you are having tests or treatment for anything else, always mention your cancer treatment. For example, if you are visiting your dentist.
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, and yellow fever.
You can usually 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 a vaccine in relation to your cancer treatment.
You can be in contact with other people who have had live vaccines as injections. If someone has had a live vaccine by mouth or nasal spray there may be a small risk the vaccine virus can be passed onto you if your is weakened.
Your healthcare team will let you know if you need to take any precautions if you are in close contact with someone who has had a live vaccine.
For further information about this treatment and possible side effects go to the electronic Medicines Compendium (eMC) website. You can find the patient information leaflet on this website.
You can report any side effect you have to the Medicines and Healthcare products Regulatory Agency (MHRA) as part of their Yellow Card Scheme.
Last reviewed: 31 Oct 2025
Next review due: 31 Oct 2028
Cutaneous T cell lymphoma (CTCL) is the most common type of skin lymphoma. The most common types of CTCL are mycosis fungoides (MF) and Sezary syndrome.
Cancer drugs have side effects and these can vary from person to person. But there are things that you can do to help you cope.
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