What is obinutuzumab (Gazyvaro®)?

Obinutuzumab (Gazyvaro®) is used to treat:

It is sometimes used to treat other cancers.


Obinutuzumab belongs to a group of targeted therapy drugs known as monoclonal antibodies.

These drugs work by targeting specific proteins (receptors). Obinutuzumab targets a protein called CD20 on the surface of white blood cells called B-lymphocytes (B-cells). It then triggers the body’s immune system to attack the cells and destroy them. 


How obinutuzumab is given

You will be given obinutuzumab at a day unit or during a stay in hospital. It is usually given in combination with chemotherapy drugs. It can also be given on its own. Your doctor or nurse will explain how it will be given.

During treatment you usually see a cancer doctor, a cancer nurse or a specialist nurse, and a specialist pharmacist. This is who we mean when we mention doctor, nurse, or pharmacist in this information.


You will see a doctor or nurse before you have your treatment. They will ask you how you have been feeling. If your blood results are okay, the pharmacist will prepare your treatment. Your nurse will tell you when your treatment is likely to be ready. 

The drug can be given through: 

  • a short, thin tube the nurse puts into a vein in your arm or hand (cannula)

Your course of treatment

You usually have a course of several cycles of treatment over a few months. Your nurse, pharmacist or doctor will discuss your treatment plan with you

If you have follicular lymphoma, you might continue to have obinutuzumab on its own after you have finished chemotherapy. This is called maintenance therapy. This can continue for up to 2 years.

About side effects




Serious and life-threatening side effects


Contact the hospital


More information


Side effects while treatment is being given

Some people may have side effects while they are being given the treatment or shortly after they have it:

Allergic reaction

Some people have a reaction to obinutuzumab. This is more common the first time it is given. You will be given drugs to help reduce the chance of getting a reaction.

Your nurse will check you for signs of a reaction during your infusion. Tell the nurse straight away if you start to feel sick or have any signs of a reaction. They can slow down the infusion and give you drugs to treat it. 

Signs of a reaction can include: 

  • feeling hot or flushed
  • a skin rash
  • itching
  • shivering
  • feeling dizzy
  • a headache
  • feeling breathless 
  • swelling of your face or mouth
  • pain in your back, tummy, or chest


Blood pressure

Some people's blood pressure falls while they are having obinutuzumab. If you usually take medicine to lower your blood pressure, your doctor may ask you not to take it for 12 hours before having obinutuzumab. Sometimes, obinutuzumab can make your blood pressure go up. Your nurse will check your blood pressure regularly.

Common side effects

Risk of infection



  • you suddenly feel unwell, even with a normal temperature
  • you have symptoms of an infection

Symptoms of an infection include:

  • feeling shivery and shaking
  • a sore throat
  • a cough
  • breathlessness
  • diarrhoea



Bruising and bleeding



  • nosebleeds
  • bleeding gums
  • heavy periods


Anaemia (low number of red blood cells)


  • pale skin
  • lack of energy
  • feeling breathless
  • feeling dizzy and light-headed.

Tell your doctor or nurse if you have these symptoms.


Feeling sick





  • Do regular gentle exercise, like going for short walks.




If you have diarrhoea:

  • contact the hospital for advice.

Hair loss

Your hair may get thinner. But you are unlikely to lose all the hair from your head. Hair loss usually starts after your first or second treatment. It is almost always temporary, and your hair will usually grow back after treatment finishes. Your nurse can talk to you about ways to cope with hair loss.

Skin changes

Obinutuzumab may affect your skin and cause itching and eczema. Tell your doctor or nurse about any skin changes. They can give you advice and prescribe creams if needed. Any changes to your skin are usually temporary and improve when treatment finishes.

Nose irritation

This treatment may cause a blocked or runny nose. Tell your doctor or nurse if this happens. There may be medicines that may help.

Muscle, joint or back pain

You may get pain in your muscles, joints or back. If this happens, tell your doctor so they can give you painkillers. Tell them if the pain does not get better.


This treatment may cause headaches. If you have headaches, tell your doctor. They may give you painkillers to help.

Difficulty sleeping and mood changes

This treatment may cause difficulty sleeping. Some people may have depression or anxiety. If you notice these changes or any other changes to your mood, talk to your doctor or nurse.

Effects on the lungs


  • a cough
  • wheezing
  • breathlessness.


High blood pressure

Obinutuzumab may cause an increase in blood pressure during treatment. Your nurse will check it regularly.

Effects on the heart

This treatment can affect the way the heart works. You may notice your heart is beating too fast or is irregular. Tell your doctor if you notice this.


Contact a doctor straight away if you:

  • have pain or tightness in your chest
  • feel breathless or dizzy
  • feel your heart is beating too fast or too slowly.


Less common side effects

Effects on the nervous system

Rarely, this treatment can affect the nervous system. It can cause a condition called PML (progressive multifocal leukoencephalopathy). Symptoms include:

  • difficulty speaking
  • difficulty walking
  • memory loss
  • confusion
  • changes in your eyesight.

Contact the hospital straight away if you have any of these symptoms. Or if someone with you notices you have these symptoms.


Hepatitis B reactivation

If you have had a liver infection in the past called hepatitis B, obinutuzumab can sometimes make it active again. Your doctor or nurse will talk to you about this and test you for hepatitis B. You may be given treatment to reduce the risk of this happening.

Raised levels of uric acid (tumour lysis syndrome)

This drug may cause the cancer cells to break down quickly. This releases uric acid (a waste product) into the blood. The kidneys usually get rid of uric acid but may not be able to cope with large amounts. Too much uric acid can cause swelling and pain in the joints, which is called gout.

Your doctor may give you tablets called allopurinol to help prevent this. Drinking at least 2 litres (3½ pints) of fluid a day will also help. You will have regular blood tests to check the uric acid levels.

Second cancer

Obinutuzumab can increase the risk of developing types of skin cancer called squamous cell carcinoma and basal cell carcinoma. But the benefits of treatment usually far outweigh this risk. Your doctor can talk to you about this.

Other information

Other medicines


  • medicines you have been prescribed
  • medicines you buy in a shop or chemist
  • vitamins, herbal drugs and complementary therapies.













Medical and dental treatment

