90Y-Ibritumomab tiuxetan (Zevalin®)

This information is about Zevalin® (pronounced zev-a-lin), which is also known as 90Y-Ibritumomab tiuxetan. It is used to treat people with a type of non-Hodgkin lymphoma called follicular lymphoma. Zevalin may also be used to treat other types of cancer as part of a research trial.

• Zevalin
• Monoclonal antibodies
• Radioisotopes
• How Zevalin works
• How it is given
• Possible side effects
• Additional information

Zevalin

Zevalin is used to treat follicular lymphoma, which is a type of non-Hodgkin lymphoma (NHL). NHL is a cancer of the lymphatic system (the network of glands in our bodies that defend against infection).

Zevalin is a type of drug called a radiolabelled monoclonal antibody. This means that it is a monoclonal antibody that has been combined with a radioactive substance. It is currently given to people who have been treated with another monoclonal antibody, rituximab, but whose lymphoma either did not respond or came back.

Monoclonal antibodies

Monoclonal antibodies are used to try to destroy some types of cancer cells while causing as little harm as possible to normal cells. They work by recognising certain proteins that are found on the surface of particular cancer cells, and ‘locking’ onto them (like a key in a lock). This may trigger the body’s immune system to attack the cancer cells and can sometimes cause the cells to destroy themselves.

Zevalin is used with rituximab (Mabthera®). Together they lock 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). CD20 is also present on the surface of most of the abnormal B-cell lymphocytes, which occur in many types of non-Hodgkin lymphoma. The monoclonal antibodies attack both normal and abnormal (malignant) B-cell lymphocytes.

Radioisotopes

Radioisotopes are atoms that give off energy in the form of radiation. Zevalin is a monoclonal antibody that is combined with the radioisotope Yttrium-90 (90Y) (pronounced it-ree-um). Yttrium-90 produces radiation that is strong enough to destroy cancer cells. It can also affect normal cells.

How Zevalin works

As Zevalin enters the bloodstream, the monoclonal antibody portion recognises and attaches to the CD20 protein. Energy is then released from the yttrium radioisotope, damaging or killing the B-cell. Zevalin attacks both normal and abnormal (malignant) B-cell lymphocytes. However, the body quickly replaces any normal white blood cells that are damaged, so the risk of side effects from this is very small.

How it is given

Zevalin is given as a single 'one-off' treatment and not as repeated courses of treatment.

It consists of two components, given approximately one week apart:

• Rituximab
• Zevalin.

Rituximab is given on the first day of treatment to reduce the number of normal healthy B-cells. This prevents the Zevalin from attaching to and destroying healthy, non-cancerous cells. Rituximab is given as a drip into a vein (intravenous infusion). It is given slowly over a few hours. You will be given some steroids and antihistamines beforehand to reduce the risk of an allergic reaction.

You will receive a second infusion of rituximab about one week after your first dose. Within four hours of this infusion you will go to the nuclear medicine or radiotherapy department to have the Zevalin treatment. This is given by drip and takes about ten minutes.

Possible side effects

Each person’s reaction to treatment is different. Some people have very few side effects, while others may experience more. The side effects described here will not affect everyone. We have outlined the most common and the less common side effects, so that you can be aware of them if they occur. However, we have not included those which are very rare and therefore extremely unlikely to affect you. If you do notice any effects which you think may be due to the drugs, but which are not listed here, please discuss them with your doctor or nurse.

Immediate side effects

While receiving the drugs, people have experienced some of the following: shortness of breath, facial flushing, cough, chills, irritation of the throat, fever, headache, nausea, vomiting, abdominal pain, back pain, dizziness and a rash.

If you have any symptoms during the infusions it is important to tell the nurse or doctor immediately. These can be signs of an allergic reaction and need prompt treatment.

Side effects following treatment

Lowered resistance to infection Zevalin can reduce the production of white blood cells by the bone marrow, making you more prone to infection. This effect can occur up to two months after the end of treatment. Your blood count may remain low for a few weeks.

Contact your doctor or the hospital straightaway if:

• Your temperature goes above 38°C (100.5°F)
• You suddenly feel unwell (even with a normal temperature).

Your doctors will check your blood levels during treatment and as part of your follow-up.

Bruising and bleeding Zevalin 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.

Flu-like symptoms These may include fever, chills, headaches, joint and muscle aches. These effects may occur a few hours after the drug is given but do not usually last for more than a day or two.

Feeling sick (nausea) and occasional vomiting Your doctor can now prescribe very effective anti-sickness (anti-emetic) 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 medication that may be more effective.

Diarrhoea This can usually be controlled with anti-diarrhoea medicine, but let your doctor know if it is severe or if it continues. It is important to drink plenty of fluids if you have diarrhoea.

Loss of appetite This is usually mild and may last a day or so. A dietitian or specialist nurse at your hospital can give advice and tips on boosting your appetite, coping with eating difficulties and maintaining weight.

Constipation This can usually be managed by eating a high fibre diet and drinking plenty of fluids. You may also need simple laxatives. Let your doctor know if you become constipated.

Rashes and increased sweating Zevalin can cause a rash (which may be itchy) and increased sweating. Tell your nurse or doctor if these are a problem.

Pain in the joints or muscles It is important to tell your doctor about this, so that appropriate painkillers can be prescribed.

Additional information

Precautions are needed after treatment with Zevalin because the radiation effects of the drug can stay in the body and bodily fluids for a short time afterwards. This includes the blood, stools, urine and saliva. Therefore, for seven days after therapy, you should avoid transfer of body fluids. It is important to wash your hands thoroughly after going to the toilet and clear up any spillages. You should also use a condom during sexual intercourse.

All of this will help to minimise exposure to radiation for those close to you.

Pregnancy should be avoided for one year after treatment.

Some medicines should only be used under the supervision of your doctor while you have Zevalin treatment. This includes blood thinners (anticoagulants) and drugs such as aspirin and ibuprofen.