In the U.S.—

Other commonly used names are: IDEC-2B8 (ibritumomab tiuxetan) IDEC-Y2B8 (yttrium-90–ibritumomab tiuxetan) IDEC-In2B8 (indium-111–ibritumomab tiuxetan) IDEC-129

• Monoclonal antibody
• antineoplastic (radioactive)

Ibritumomab Tiuxetan (ib-ri-TU-moe-mab ) (tie-ux-EH-tan) is a protein called a monoclonal antibody. It is used along with another monoclonal antibody (rituximab) and two radioactive pharmaceuticals (In-111 and Y-90). Ibritumomab tiuxetan is used to treat a type of cancer called non-Hodgkin's lymphoma.

Ibritumomab Tiuxetan is to be administered only by or under the immediate supervision of your doctor. It is available in the following dosage form:

Parenteral
• Injection (U.S.)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For ibritumomab tiuxetan, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual reaction to ibritumomab tiuxetan, rituximab, yttrium chloride, indium chloride or to mouse proteins.

Pregnancy—Ibritumomab tiuxetan is not recommended during pregnancy. It has been shown to cause birth defects. However, this medicine may be needed in serious diseases or other situations that threaten the mother's life. Be sure you have discussed this with your doctor.

Women who are able to bear children should use some kind of birth control during treatment with ibritumomab tiuxetan and for up to 12 months after treatment has ended.

Before receiving this medicine, make sure your doctor knows if you are pregnant.

Tell your doctor right away if you think you have become pregnant while receiving ibritumomab tiuxetan.

Breast-feeding—It is not known whether ibritumomab tiuxetan passes into the breast milk. However, because of the possibility of serious effects, breast-feeding is not recommended while you are receiving this medicine.

Children—Studies on this medicine have been done only in adult patients, and there is no specific information comparing use of ibritumomab tiuxetan in children with use in other age groups.

Older adults—This medicine has been tested in a limited number of patients 65 years of age or older and has not been shown to cause different side effects or problems in older people than it does in younger adults.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking ibritumomab tiuxetan, it is especially important that your doctor and pharmacist know if you are taking any of the following:

• Anticoagulants (blood thinners such as warfarin [Coumadin]) or
• Medicines that prevent platelets from sticking together (clopidogrel [e.g., Plavix], ticlopidine [e.g., Ticlid])—Use with ibritumomab tiuxetan may increase the risk of bleeding.

• If you have ever been treated with radiation or cancer medicines—Ibritumomab tiuxetan may increase the effects of these medicines on the blood.

Dosing—

The dose of ibritumomab tiuxetan will be different for different patients. The dose that is used may depend on a number of things, including your size. Ibritumomab tiuxetan is usually given by a doctor in the hospital or an outpatient clinic. If you have any questions about the proper dose of ibritumomab tiuxetan, ask your doctor.

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

While you are being treated with ibritumomab tiuxetan, and after you stop treatment with it, do not have any immunizations (vaccinations) without your doctor's approval. Ibritumomab tiuxetan may lower your body's resistance and there is a chance you might get the infection the immunization is meant to prevent. In addition, other persons living in your household should not take oral polio vaccine since there is a chance they could pass the polio virus on to you. Also, avoid persons who have taken oral polio vaccine within the last several months. Do not get close to them, and do not stay in the same room with them for very long. If you cannot take these precautions, you should consider wearing a protective face mask that covers the nose and mouth.

Ibritumomab tiuxetan can temporarily lower the number of white blood cells in your blood, increasing the chance of getting an infection. It can also lower the number of platelets, which are necessary for proper blood clotting. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection or bleeding:

• Avoid people with infections. Check with your doctor immediately if you think you are getting an infection or if you get a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
• Check with your doctor immediately if you notice any unusual bleeding or bruising; black, tarry stools; blood in urine or stools; or pinpoint red spots on your skin.
• Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.
• Do not touch your eyes or the inside of your nose unless you have just washed your hands and have not touched anything else in the meantime.
• Be careful not to cut yourself when you are using sharp objects such as a safety razor or fingernail or toenail cutters.
• Avoid sports or other situations where bruising or injury could occur.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• More common
  • Black, tarry stools;  bleeding gums;  blood in urine or stools;  cough or hoarseness ;  coughing up blood;  difficulty in breathing or swallowing;  dizziness;  fever or chills;  headache;  increased menstrual flow or vaginal bleeding;  large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, sex organs;  lower back or side pain;  noisy breathing;  nosebleeds;  painful or difficult urination;  pale skin;  paralysis;  pinpoint red spots on skin;  prolonged bleeding from cuts;  red stools;  red or dark brown urine ;  shortness of breath;  sore throat;  sores, ulcers, or white spots on lips or in mouth;  swollen glands;  tightness in chest;  troubled breathing with exertion ;  unusual bleeding or bruising;  unusual tiredness or weakness;  wheezing 
  
  

• Less common
  • Bloody nose that does not stop after pinching the nasal alae together and holding them continuously for 5 to 10 minutes;  bluish lips or skin;  chest pain or discomfort;  confusion;  diarrhea;  fainting;  fast heartbeat;  hives;  itching;  lightheadedness ;  not breathing;  pain at site of tumor;  puffiness or swelling of the eyelids or around the eyes, face, lips or tongue;  rapid, shallow breathing;  skin rash;  small red or purple spots on skin;  unusual vaginal bleeding;  vomiting blood or material that looks like coffee grounds 
  
  

• Rare
  • Agitation;  anxiety;  back pain;  blurred vision;  coma;  drowsiness;  fast, pounding, or irregular heartbeat or pulse;  hallucinations ;  inability to speak;  irregular heartbeat;  irritability;  mood or mental changes;  nausea;  redness of skin;  seizures;  severe headache;  slurred speech;  stiff neck;  temporary blindness;  vomiting;  weakness in arm and/or leg on one side of the body, sudden and severe;  welts 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Abdominal pain or stomach pain;  bruising ;  constipation;  difficult or labored breathing;  difficulty in moving;  faintness or lightheadedness when getting up from a lying or sitting position;  fear;  feeling of warmth;  full or bloated feeling or pressure in the stomach;  joint pain;  lack or loss of strength;  large, flat, blue or purplish patches in the skin;  loss of appetite;  muscle aching or cramping;  muscle pain or stiffness;  nervousness;  pain;  pain in joints;  rash ;  redness of the face, neck, arms and occasionally, upper chest;  runny nose;  sleeplessness;  sneezing;  stuffy nose;  sudden or increased sweating;  swollen joints;  swelling of abdominal or stomach area;  swelling of hands, ankles, feet, or lower legs;  throat irritation;  trouble sleeping;  unable to sleep;  weight loss 
  
  

• Less common
  • Acid or sour stomach;  belching;  heartburn;  indigestion;  stomach discomfort, upset or pain;  swelling, or redness in joints 
  
  

For several months after receiving this therapy, it may still produce some side effects that need attention. During this period of time check with your doctor immediately if you notice any of the following:

• Bleeding gums;  blurred vision;  bone pain;  chills;  confusion;  cough ;  coughing up blood;  difficulty in breathing or swallowing;  dizziness;  fainting;  fast heartbeat;  fever;  headache, sudden and severe;  inability to speak;  increased menstrual flow or vaginal bleeding;  lightheadedness;  lower back or side pain;  nosebleeds ;  painful or difficult urination;  pale skin;  paralysis;  prolonged bleeding from cuts;  rapid, shallow breathing;  red or dark brown urine;  red or black, tarry stools;  secondary malignancy;  seizures;  shallow breathing;  shortness of breath;  slurred speech ;  sore throat;  temporary blindness;  ulcers, sores, or white spots in mouth ;  unusual bleeding or bruising;  unusual tiredness or weakness ;  weakness in arm and/or leg on one side of body, sudden and severe 

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.