Rituximab (Mabthera)

Rituximab (pronounced rit-ux-i-mab) is a monoclonal antibody, which is a type of biological therapy. Rituximab is also known by its brand name, Mabthera. It is a treatment for low grade lymphoma, high grade B cell lymphoma, chronic lymphocytic leukaemia, and hairy cell leukaemia that has come back after treatment. Rituximab is also used for some non cancer related illnesses.

Rituximab targets a protein called CD20 on the surface of the leukaemia and lymphoma cells. The antibody sticks to all the CD20 proteins it finds. Then the cells of the immune system pick out the marked cells and kill them. All fully developed B cells have CD20 on their surface, including B lymphoma cells.

Early B cells don’t have the CD20 protein and so aren’t killed. This means they can produce new healthy B cells. So the number of B cells in the body goes back to normal a few months after treatment.

You have rituximab through a drip into a vein (infusion). You may have to stay in hospital overnight for the first treatment, because some people have a reaction to it. You have the first treatment in hospital, over a few hours. If you don’t have problems, you can have later treatments more quickly and as an outpatient.

You usually have treatment once a week for 4 weeks. But the number of treatments depends on whether you have had treatment before and the type of cancer you have. If you have high grade lymphoma and haven’t had treatment before, you may have rituximab with CHOP chemotherapy – RCHOP.

The side effects associated with rituximab are listed below. There is more information about RCHOP in our cancer drugs section. The side effects of rituximab may be different if you have it with other drugs.

More than 10 in every 100 people have one or more of the side effects listed below.

Temporary drop in the number of blood cells made by the bone marrow, causing

• Increased risk of getting an infection from a drop in white blood cells – it is harder to fight infections and you can become very ill. You may have headaches, aching muscles, a cough, sore throat, pain passing urine or feel cold and shivery
• Tiredness and breathlessness due to a drop in red blood cells (anaemia) – you may need a blood transfusion
• Bruising easily due to a drop in platelets – you may have nosebleeds, bleeding gums after brushing your teeth, or lots of tiny red spots or bruises on your arms or legs (known as petechia)

Some of these side effects can be life threatening, particularly infections. You should contact your doctor if you have any of these effects. Your doctor will check your blood counts regularly to see how well your bone marrow is working.

Other common side effects include

• Flu like symptoms, including fever and chills, in half the people treated (50%) – taking paracetamol can help
• Feeling sick affects 1 in 5 people (20%), but is usually well controlled with anti sickness medicines
• Diarrhoea is usually mild but tell your doctor or nurse, as you can have medicines to control it
• A rash which may be itchy
• Low blood pressure in about 1 in 10 people (10%) and more rarely, raised blood pressure
• Night sweats in about 3 in 20 people (15%)
• Stomach pain
• Feeling weak in about 1 in 4 people (25%)
• A runny nose (rhinitis) – this is usually mild and goes away within an hour of the infusion
• Loss of fertility – we don’t know exactly how this drug may affect your fertility, so it’s important to discuss this with your doctor before starting treatment if having a baby is important to you
• We don’t yet know if rituximab can harm a developing baby, so you should talk about contraception with your doctor or nurse before having treatment
• You should not breastfeed while having this drug as it may come through in the breast milk

Between 1 and 10 in every 100 people have one or more of these.

• A reaction to rituximab during infusion, causing flu like symptoms such as a fever, chills and shivering (rigors), a headache and feeling sick – your doctor will give you medicines beforehand to try to prevent a reaction. If you do have a reaction, your nurse will slow or stop your drip for a while
• A cough and breathlessness – the rituximab can cause irritation of the lungs. Tell your doctor or nurse if this continues
• A mild effect on the liver, which does not cause symptoms and will almost certainly go back to normal when the treatment is finished – you will have regular blood tests to keep an eye on how your liver is working
• Loss of appetite
• Indigestion
• Dizziness
• About 1 in 20 people (5%) have a sudden feeling of warmth and reddening of the face during the infusion – tell your nurse straight away if this happens to you

Fewer than 1 in 100 people have these.

• Damage to your kidneys caused by chemicals from the dying cancer cells collecting in the blood (tumour lysis syndrome) – you will have regular blood tests to check the chemical balance of your blood and may be given tablets
• About 1 in 20 people (5%) have a more severe allergic reaction, with wheezing, an itchy rash and a drop in blood pressure – your doctor or nurse will give you medicines beforehand to try to prevent a reaction and if you do have a reaction, your nurse will slow or stop your drip for a while

The side effects above may be mild or more severe. A side effect may get better or worse through your course of treatment, or more side effects may develop as the course goes on. This depends on

• How many times you've had the drug before
• Your general health
• The amount of the drug you have (the dose)
• Other drugs you are having

Talk to your doctor, pharmacist or nurse about all your side effects so that they can help you manage them. Your specialist, clinic or ward nurse will give you a contact number. You can ring if you have any questions or problems. They can give you advice or reassure you. If in doubt, call them.

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and other over the counter remedies – some drugs can react together.

You should not have immunisations with live vaccines while you are having this treatment or for at least 6 months afterwards. In the UK, these include rubella, mumps, measles (usually given together as MMR), BCG and yellow fever. You can have other vaccines, but they may not give you as much protection as usual until your immune system has fully recovered.

It is safe for you to be in contact with other people who've had live vaccines as injections. There can be problems with oral vaccines, but not many people in the UK have oral vaccines now. So there is usually no problem in being with any baby or child who has recently had any vaccination in the UK. You might need to make sure that you aren't in contact with anyone who has had oral polio, cholera or typhoid vaccination recently, particularly if you live abroad.