Ibritumomab (Zevalin)

How does it work?

Zevalin infusion contains Yttrium-90 radiolabelled ibritumomab, which is a type of medicine known as a radiolabelled monclonal antibody. This means that it is a monclonal antibody that has been combined with a radioactive substance. It is used to treat a type of cancer called non-Hodgkins lymphoma.

Lymphomas are cancers involving white blood cells called lymphocytes. Cancer occurs when these lymphocytes, for some reason, begin to multiply in an uncontrolled way. This can cause a lump or tumour in the lymph nodes. Lymphocytes are normally involved in fighting infection and they travel around the lymphatic system and the bloodstream to do this. If abnormal cancerous lymphocytes travel, the cancer can spread to other lymph nodes and other areas of the body.

Zevalin is used to treat non-Hodgkins lymphoma that involves a sub-group of lymphocytes called B lymphocytes. It works by targeting radiation to attack the abnormal B lymphocytes.

Ibritumomab works in a similar way to the natural antibodies produced by our immune system. Our natural antibodies recognise foreign invaders and bind to them, helping our immune systems to attack them and protect us from infections. Monoclonal antibodies like ibritumomab are made in laboratories and are designed to recognise particular proteins in a similar way.

Ibritumomab specifically recognises and binds to a protein called CD20, which is found on the surface of cancerous B lymphocyte cells. The ibritumomab is combined with a radioisotope called Yttrium-90 or Y-90. This produces radiation that is strong enough to destroy cancer cells. When the ibritumomab binds to the cancerous B cells, radiation energy from the Y-90 is released that damages or kills the B cell.

Unfortunately ibritumomab can also bind to healthy B cells, because these also carry the CD20 protein. This can lead to healthy cells being damaged by the radiation. For this reason, pre-treatment is given with a similar medicine called rituximab (Mabthera). Rituximab is another monoclonal antibody that recognises and binds to the CD20 protein on B cells. However, it does not carry radiation; it simply causes the immune system to attack the B cells.

Rituximab is given on the first day of treatment to reduce the numbers of normal healthy B cells and prevent them being damaged by the Zevalin radiation. About a week later, another dose of rituximab is given, followed within four hours by Zevalin given by a drip into a vein (intravenous infusion). This takes about ten minutes. The Zevalin drip is a one-off treatment for non-Hodgkins lymphoma that has not responded to, or has come back after treatment with rituximab.

The body quickly replaces any normal healthy white blood cells that have been damaged by the treatment.

What is it used for?

  • A type of cancer of the lymphatic system called CD20 positive follicular B-cell non-Hodgkins lymphoma (when the cancer has not responded to or has come back after treatment with a medicine called rituximab).


  • Molecules called cytokines may be released into the body when the B lymphocytes are destroyed by rituximab. This can lead to severe reactions such as shortness of breath, fever, chills, rash and a fall in blood pressure. You will usually be given some painkillers, antihistamine and possibly steroids before the rituximab drip to help prevent a reaction. Infusion–related reactions due to Zevalin are less common and less severe, however, you should let the person administering your drip know if you have any symptoms during any of the treatments.
  • You will need to have a blood test to check the levels of your blood cells before you have treatment with this medicine and at regular intervals after the treatment.
  • This medicine can decrease the number of blood cells in your blood. A low white blood cell count can increase your susceptibility to infections; a low red blood cell count causes anaemia and a low platelet count can cause problems with blood clotting. For this reason, you should tell your doctor immediately if you experience any of the following symptoms during or after your treatment, as they may indicate problems with your blood cells: unexplained bruising or bleeding, purple spots, sore mouth or throat, mouth ulcers, high temperature (fever) or other signs of infection, or suddenly feeling tired, breathless, or generally unwell.
  • The amount of radiation that your body will be exposed to during a course of Zevalin is smaller than it would be in radiotherapy. It is not possible for other people to be exposed to this radiation by being in contact with you after your treatment. However, some of the radiation does leave your body in your urine, so it is important to thoroughly wash your hands after urinating for a week following your Zevalin infusion.
  • This medicine may be harmful to an unborn baby. Women who could get pregnant must use an effective method of contraception to prevent pregnancy and men must use an effective method of contraception to avoid fathering a child, both during treatment and for 12 months after treatment with this medicine is finished.
  • Your ability to get pregnant or father a child may be affected by treatment with this medicine. It is important to discuss fertility with your doctor before starting treatment.

Use with caution in

  • People with decreased production of blood cells by the bone marrow.

Not to be used in

  • Children and adolescents under 18 years of age.
  • Allergy to rituximab or mouse proteins.
  • People with low numbers of blood cells called neutrophils and platelets in their blood.
  • People in whom more than 25 per cent of the bone marrow has been invaded by the cancer cells.
  • People who have had external beam radiation treatment of more than 25 per cent of their bone marrow.
  • People who have had a bone marrow transplant or stem cell support.
  • Pregnancy.
  • Breastfeeding.

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

  • This medicine may be harmful to an unborn baby. It must not be given to pregnant women. If you have missed a period or think you could be pregnant you must inform your doctor before your treatment starts. Women who could get pregnant must use an effective method of contraception to avoid pregnancy and men must use an effective method of contraception to avoid fathering a child, both during treatment and for 12 months after treatment with this medicine is finished. Seek further medical advice from your doctor.
  • It is not known if this medicine passes into breast milk. However, because it may pass into breast milk and harm a nursing infant, it should not be given to women who are breastfeeding. Women who have treatment with this medicine should not breastfeed. Seek further medical advice from your doctor.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

  • Decreased numbers of white blood cells, red blood cells and platelets in the blood.
  • Disturbances of the gut such as nausea, vomiting, abdominal pain, constipation, diarrhoea, indigestion.
  • Fever and chills.
  • Feeling weak.
  • Infections.
  • Loss of appetite.
  • Pain in the muscles, joints, back, neck or tumour.
  • Dizziness.
  • Headache.
  • Difficulty sleeping (insomnia).
  • Anxiety.
  • Cough.
  • Nasal inflammation (rhinitis).
  • Rash or itching.
  • Increased sweating.
  • Increased heart rate.
  • Severe allergic reactions.

The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.

For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

It is important to tell your doctor if you are taking any other medicines, including over-the-counter and herbal medicines, before you have treatment with this medicine. Similarly, always seek advice from your doctor or pharmacist before taking any new medicines during and after treatment with this medicine, so they can check that the combination is safe.

As this medicine attacks your B cells, which are part of your immune system, it may make it hard for your body to produce antibodies in response to vaccinations. This means that vaccines may potentially be less effective if given during treatment, and live vaccines may cause serious infections. For this reason, if you need to have any vaccinations, these should preferably be completed a few weeks before your treatment.

Other medicines containing the same active ingredient

There are currently no other medicines available in the UK that contain radiolabelled ibritumomab as the active ingredient.