An anti-CD20 antibody
Obinutuzumab
A targeted antibody for certain leukaemia and lymphoma, given by drip by oncology teams.
What is Obinutuzumab?
Obinutuzumab is a targeted cancer medicine (a monoclonal antibody) used for certain blood cancers, including chronic lymphocytic leukaemia (CLL) and follicular lymphoma. It is given by a specialist oncology team as a drip into a vein, often with chemotherapy. It targets a marker called CD20 on the cancerous white cells. Infusion reactions can happen, especially with the first dose, and it raises infection risk. It can reactivate hepatitis B, so you are screened for this first, and it can lower blood counts, which are monitored.
Education and reference only. This is a plain-language guide to Obinutuzumab — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Obinutuzumab is a monoclonal antibody, a laboratory-made protein that targets CD20, a marker on a type of white blood cell called the B cell. It is used for certain blood cancers, including chronic lymphocytic leukaemia (CLL) and follicular lymphoma, usually alongside chemotherapy. It is not a tablet; it is given by oncology specialists as a drip into a vein. The brand name is Gazyvaro.
How it works
B cells are a type of white blood cell, and in CLL and follicular lymphoma these cells become cancerous; they carry a marker called CD20 on their surface. Obinutuzumab locks onto CD20 and flags the cancerous B cells so the immune system destroys them, and it can also trigger the cells to die directly. It is usually combined with chemotherapy, which works in a different way, to control the disease more effectively. Because it clears B cells, which are part of the immune system, it lowers the body's defences for a time and can also allow a hidden hepatitis B infection to flare up.
Company & origin
Originated / developed by: Roche.
A targeted cancer antibody used in the UK by oncology teams for certain leukaemias and lymphomas, such as CLL and follicular lymphoma.
Practical use
How to take Obinutuzumab
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- It is given by your oncology team as a drip into a vein, often alongside chemotherapy; it is never taken as a tablet.
- You will be screened for hepatitis B before starting, and given protective treatment and monitoring if needed.
- You will be given supportive medicines before treatment, and the first drips are given slowly to reduce reactions.
- Report signs of infection such as fever, chills, sore throat or a cough promptly, as your defences are lowered.
- Tell your team about any new confusion, weakness, or vision or speech problems, and attend all your blood tests.
Weighing it up
Advantages & disadvantages of Obinutuzumab
Advantages
- Specifically targets CD20 on cancerous B cells and helps the immune system destroy them.
- Combined with chemotherapy, it can effectively control CLL and follicular lymphoma.
- Given as a planned course, with most reactions occurring around the first dose.
Disadvantages
- Infusion reactions are common, especially with the first dose, so early treatments take longer.
- Lowers the body's defences and blood counts, raising the risk of infections.
- Can reactivate hepatitis B, so screening is needed first, and rarely is linked to a serious brain infection.
Practical use
Good to know
Before starting, you will be screened for hepatitis B, because obinutuzumab can reactivate a past or hidden hepatitis B infection, which can be serious; if needed, protective antiviral treatment is given and you are monitored. Infusion reactions are common, particularly with the first dose, so the first treatments are given slowly with supportive medicines and close watching. It lowers the body's defences and can reduce blood counts, so report fever, chills, a cough or any sign of infection promptly, and your blood counts are checked regularly. Rarely, it has been linked to a serious brain infection (PML), so tell your team about any new confusion, weakness, vision or speech problems. Your team will also discuss vaccinations, which are best timed around treatment.
Who should not take it / use with caution
- Anyone who has had a serious allergic reaction to obinutuzumab should not receive it again.
- People with active untreated hepatitis B need this addressed first, as the medicine can make it flare.
- It is avoided in pregnancy because it may harm the developing baby, so effective contraception is advised.
Monitoring
- Hepatitis B screening before treatment, with antiviral cover and monitoring if needed.
- Regular blood tests to check blood counts and how the cancer is responding.
- Close watching for infusion reactions and infections, and for any new neurological symptoms.
Side effects
- Infusion reactions such as chills, fever, flushing and breathlessness, mainly with the first dose.
- A higher risk of infections and lower blood counts; report fever, chills or feeling unwell promptly.
- Tiredness, cough and, rarely, hepatitis B flare-up or a serious brain infection (PML).
Key interactions
- Given as a planned combination with chemotherapy rather than an accidental interaction.
- Live vaccines are generally avoided during treatment, so discuss any vaccinations with your team.
- Tell your team about all your medicines and your hepatitis history so screening and monitoring can be arranged.
Available as: Given by oncology teams as a drip into a vein.
Answers
Obinutuzumab: frequently asked questions
Why am I screened for hepatitis B before obinutuzumab?
Obinutuzumab can reactivate a past or hidden hepatitis B infection, which can be serious, so you are screened first and given protective treatment and monitoring if needed.
What is obinutuzumab used for?
It is used for certain blood cancers, including chronic lymphocytic leukaemia (CLL) and follicular lymphoma, usually given together with chemotherapy.
Why is the first drip given slowly?
Infusion reactions are most likely with the first dose, so it is given slowly with supportive medicines and close watching to keep you safe and comfortable.
Will it make me prone to infections?
Yes, it lowers your defences and can reduce blood counts, so report fever, chills or a cough promptly; your team checks your blood counts and discusses vaccinations.
What serious symptoms should I report?
Tell your team urgently about any new confusion, weakness, or problems with your vision or speech, as well as signs of infection, so they can be checked quickly.
Authoritative sources
- BNF
- NICE CKS
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