Rituximab (Mabthera®)

This information is about the use of rituximab (pronounced ri-tucks-i-mab) as a treatment for people with cancer. It is mainly used to treat non-Hodgkin lymphoma.

• What is rituximab?
• Monoclonal antibodies
• What rituximab looks like
• How it is given
• Possible side effects
• Additional information

What is rituximab?

Rituximab belongs to a group of cancer drugs known as monoclonal antibodies. It is used to treat several types of non-Hodgkin lymphoma.

Rituximab can be given:

• in combination with the chemotherapy regimen CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone), as the first treatment for people who have diffuse large B-cell lymphoma
• in combination with the chemotherapy regimen CVP (cyclophosphamide, vincristine and prednisolone), as the first treatment for people who have advanced (stage three or four) follicular lymphoma when first diagnosed
• to people with advanced (stage three and four) follicular lymphoma, whose lymphoma has come back after initial chemotherapy.

Rituximab may also be given as part of a research trial, either in combination with chemotherapy or on its own.

Monoclonal antibodies

Monoclonal antibodies are used to try to destroy some types of cancer cells while causing little harm to normal cells. They recognise certain proteins that are found on the surface of particular cancer cells. The monoclonal antibody recognises the protein and 'locks' onto it (like a key in a lock). This may then trigger the body’s immune system to attack the cancer cells and can sometimes cause the cells to destroy themselves.

Rituximab locks onto a protein called CD20 which is found on the surface of one of the main types of normal white blood cells (B-cell lymphocytes). It is also present on the surface of most of the abnormal B-cell lymphocytes which occur in most types of non-Hodgkin lymphoma. Rituximab attacks both abnormal (malignant) and normal B-cell lymphocytes. However, the body quickly replaces any normal white blood cells which are damaged, so the risk of side effects from this is very small.

What rituximab looks like

Rituximab is a clear fluid after being diluted.

How it is given

Rituximab is given as a drip (infusion) through a fine tube (cannula) inserted into the vein. Some people can have an allergic reaction to rituximab. To reduce the risk of this, the first dose is given slowly over a number of hours. You will be given some antihistamines and steroids before the treatment to help prevent any reaction.

If you have a reaction, the infusion can be stopped and started again when the symptoms are over. You may need to stay in hospital overnight for the first treatment so that you can be monitored. After that, rituximab can usually be given in the outpatients department and over a shorter period of time.

When used by itself, rituximab is usually given weekly over a period of four weeks. The treatment may be repeated later if needed.

If rituximab is being used with chemotherapy it is given with each course of treatment.

Possible side effects

Each person's reaction to a cancer drug is different. Some people have very few side effects, while others may experience more. We have outlined the most common side effects. We have not included those that are very rare, however, and which are therefore extremely unlikely to affect you. If you notice any effects that you think may be due to the drug but which are not listed here, please discuss them with your doctor or nurse.

The side effects of rituximab are generally mild and some of these can be reduced with medicines. Side effects can begin during the first dose of the drug and may continue for a few hours afterwards, but are usually milder with following doses.

The most common side effects are described below:

Flu-like symptoms These can include a high temperature, chills, weakness, muscle aches, tiredness, dizziness and headaches. They can occur while the rituximab is being given, but do not usually last long.

Low blood pressure This may happen during the infusion, so your blood pressure will usually be regularly checked. People who normally take medicines to lower their blood pressure may be advised by the doctor to take these at least 12 hours before rituximab is given.

Feeling sick (nausea) and occasional vomiting Your doctor can now prescribe very effective anti-sickness drugs to prevent or greatly reduce nausea and vomiting. If the sickness is not controlled, or if it continues, tell your doctor. They can prescribe other anti-sickness drugs that may be more effective.

Tumour pain Some people may experience mild pain in the parts of the body where they have cancer. Painkillers can be given to relieve this.

Allergic reactions You may have a slight allergic reaction to rituximab. Signs of this include skin rashes and itching, a feeling of swelling in the tongue or throat, irritation of the nasal passages, wheezing, a cough and breathlessness. You will be monitored closely during your treatment, but let your nurse or doctor know if you have any of these symptoms. To help reduce the chance of developing an allergic reaction, antihistamines can be given before the infusion. The infusion can also be slowed down or stopped until the reaction is over.

Lowered resistance to infection Rituximab can reduce the production of white blood cells by the bone marrow, making you more prone to infection. Your blood cells will be monitored while you are taking rituximab.

Contact your doctor or the hospital straightaway if:

• Your temperature goes above 38ºC (100.5ºF)
• You suddenly feel unwell (even with a normal temperature).

You will have a blood test before having more chemotherapy to make sure that your cells have recovered. Occasionally it may be necessary to delay your treatment if the number of blood cells (the blood count) is still low.

Bruising or bleeding Rituximab can reduce the production of platelets (which help the blood to clot). Let your doctor know if you have any unexplained bruising or bleeding, such as nosebleeds, blood spots or rashes on the skin, and bleeding gums.

Anaemia (low number of red blood cells) While having treatment with rituximab you may become anaemic. This may make you feel tired and breathless. You may need to have a transfusion of blood if the number of red blood cells becomes too low.

Flushing You may experience a sudden warmth in your face as well as some redness or darkening. This can happen for a short period of time during the infusion.

Additional information

Rituximab may worsen heart problems for people who already have them. For this reason it is used with caution in anyone who has heart disease.