What is ibalizumab?

Ibalizumab (Trogarzo) is a medication used to treat HIV that is resistant to most currently available drugs. It is given in combination with other antiretroviral drugs and you will have a drug resistance test before starting ibalizumab to select other drugs that are active against your HIV.

How does ibalizumab work?

Ibalizumab is an antibody that blocks HIV entering immune cells. Your doctor will prescribe ibalizumab as part of your HIV treatment, along with other antiretrovirals which will probably be taken as daily tablets.

The aim of HIV treatment is to reduce the level of HIV (the ‘viral load’) in your body until it is undetectable – usually less than 50 copies of virus per ml of blood.

Taking HIV treatment and having an undetectable viral load protects your immune system and stops HIV being passed on to someone else during sex.

How do I take ibalizumab?

Ibalizumab is given as an infusion every two weeks. The infusion is given by a drip feed into a vein and must be given in a clinic. Treatment begins with an infusion of 2000mg and then 800mg every two weeks afterwards. The first infusion will last at least half an hour. If you are more than three days late for an infusion you will receive another 2000mg infusion.

You will need to spend one hour at the clinic after the first infusion to check that you do not have a reaction to it.

What are the possible side effects of ibalizumab?

All medicines have possible side effects. It’s a good idea to talk to a doctor, nurse or pharmacist about what to expect before you start taking any medication, and how to manage any side effects which occur.

A full list of side effects, including less common side effects, can be found in the patient information leaflet that comes with ibalizumab.

Side effects can be described as:

  • Common – a side effect that occurs in at least one in a hundred people (more than 1%) who take this drug.
  • Uncommon – a side effect that occurs in fewer than one in a hundred people (less than 1%) who take this drug.

Common side effects of ibalizumab include rash, diarrhoea, dizziness, headache, nausea (feeling sick), vomiting and tiredness.

Does ibalizumab interact with other drugs?

 Ibalizumab is not known to interact with any other medicines.

Can I take ibalizumab in pregnancy?

If you are considering having a baby, or think you might be pregnant, talk to your doctor as soon as possible about which combination of anti-HIV medications would be right for you. It is important to take antiretroviral treatment during pregnancy to prevent passing HIV from mother to baby.

 Ibalizumab should be used with effective contraception. Ibalizumab should not be used during pregnancy or while breastfeeding.

Can children take ibalizumab?

Ibalizumab is not licensed for use in children.

Talking to your doctor

If you have any concerns about your treatment or other aspects of your health, it’s important to talk about these. For example, if you have any symptom or side effect which may be from your treatment, or if you are finding it difficult to take your medication every day, one of your healthcare team will be able to help.


antiretroviral (ARV)

A substance that acts against retroviruses such as HIV. There are several classes of antiretrovirals, which are defined by what step of viral replication they target: nucleoside reverse transcriptase inhibitors; non-nucleoside reverse transcriptase inhibitors; protease inhibitors; entry inhibitors; integrase (strand transfer) inhibitors.

undetectable viral load

A level of viral load that is too low to be picked up by the particular viral load test being used or below an agreed threshold (such as 50 copies/ml or 200 copies/ml). An undetectable viral load is the first goal of antiretroviral therapy.

drug interaction

A risky combination of drugs, when drug A interferes with the functioning of drug B. Blood levels of the drug may be lowered or raised, potentially interfering with effectiveness or making side-effects worse. Also known as a drug-drug interaction.

viral load

Measurement of the amount of virus in a blood sample, reported as number of HIV RNA copies per milliliter of blood plasma. Viral load is an important indicator of HIV progression and of how well treatment is working. 



Any perceptible, subjective change in the body or its functions that signals the presence of a disease or condition, as reported by the patient.


Building a relationship with a doctor may take time. You may feel very comfortable talking to your doctor, but some people find it more difficult, particularly when talking about sex, mental health, or symptoms they find embarrassing. It’s also easy to forget things you wanted to talk about.

Preparing for an appointment can be very helpful. Take some time to think about what you are going to say. You might find it helpful to talk to someone else first, or to make some notes and bring them to your appointment.

For detailed information on this drug, visit the ibalizumab page in the A-Z of antiretroviral medications.

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