Pronounced: EYE-bri-TOOM-oh-mab tye-UX-e-tan
Classification: Radiolabeled Monoclonal Antibody
Ibritumomab Tiuxetan is a synthetic (man made) antibody directed against a protein called CD20, found on the surface of B cells. Antibodies are developed by the immune system to destroy foreign material (such as a germ). Ibritumomab tiuxetan binds to B cells, causing the immune system to respond and kill the cells. This manmade antibody has a radioactive isotope attached to it, which gets inserted into the B cells. Two isotopes are used; Indium 111 (In-111) is used to assess how well the antibody is distributed, but offers no radioactive treatment. Once the distribution is confirmed, the correct dose of radiation can be calculated and the second isotope, Yttrium-90 (Y-90), is given. It induces cellular damage by the forming free radicals, which damage not only the targeted B cells, but also cells in the surrounding area, a phenomenon known as the "bystander effect".
The treatment is given in two steps, the "imaging dose" and the "therapeutic dose". On day 1 (imaging dose), you will be given another targeted therapy medication, rituximab, in an IV infusion (this medication requires premedication with acetaminophen and diphenhydramine). Within four hours of completing the infusion, you will be given an infusion of In-111 ibritumomab, which takes about 10 minutes. Your doctor will calculate how well the In-111 ibritumomab was distributed in your body by taking a special type of CT scan (called an Indium scan) 48-72 hours later. If the distribution is acceptable, you proceed to step 2, if not, your team will determine why, correct the problem, and you will need to repeat step 1.
Step 2, the therapeutic dose, is given on day 7, 8 or 9. You will receive a second dose of rituximab with premedications. Within 4 hours of completing the rituxan, you will be given an infusion of Y-90 ibritumomab, which is the radioactive isotope. The dose is based on your body weight and platelet count.
There are a number of things you can do to manage the side effects of Ibritumomab Tiuxetan Talk to your doctor or nurse about these recommendations. They can help you decide what will work best for you. These are some of the most common side effects:
White blood cells (WBC) are important for fighting infection. While receiving treatment, your WBC count can drop, putting you at a higher risk of getting an infection. You should let your doctor or nurse know right away if you have a fever (temperature greater than 100.4 F), sore throat or cold, shortness of breath, cough, burning with urination, or a sore that doesn't heal.
Tips to preventing infection:
For more suggestions, read the Neutropenia Tip Sheet.
Your red blood cells are responsible for carrying oxygen to the tissues in your body. When the red cell count is low, you may feel tired or weak. You should let your doctor or nurse know if you experience any shortness of breath, difficulty breathing or pain in your chest. If the count gets too low, you may receive a blood transfusion. Read the anemia tip sheet for more information.
Platelets help your blood clot, so when the count is low you are at a higher risk of bleeding. Let your doctor or nurse know if you have any excess bruising or bleeding, including nosebleeds, bleeding gums or blood in your urine or stool. If your platelet count becomes too low, you may receive a transfusion of platelets.
Read the thrombocytopenia tip sheet for more information.
While on cancer treatment you may need to adjust your schedule to manage fatigue. Plan times to rest during the day and conserve energy for more important activities. Exercise can help combat fatigue; a simple daily walk with a friend can help. Talk to your healthcare team and see OncoLink's section on fatigue for helpful tips on dealing with this side effect.
Some patients have a reaction to the rituximab infusion, which is an essential part of the treatment with ibritumomab. If during the infusion you develop a rash, itching, fever, chills, lightheadedness or difficulty breathing, call your nurse. Medications may be given to relieve the symptoms and, in many cases, the infusion can be restarted at a slower rate.
There is a small risk of developing leukemia or myelodysplasia ("preleukemia", abnormally functioning bone marrow) due to treatment with this medication.