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Generic Name: tositumomab (TOE-sih-too-MOE-mab)
Brand Name: Bexxar

Tositumomab may cause serious allergic reactions during or within 48 hours of receiving tositumomab. Seek immediate medical attention if you experience rash; hives; itching; difficulty breathing; dizziness; unusual nausea or sweating; tightness in the chest; or swelling of the mouth, face, lips, or tongue.

Tositumomab may cause serious (possibly life-threatening) reductions in the number of white blood cells and platelets your body produces. This effect may last for an extended length of time. Additional treatment may be needed to manage this effect. Serious infections or bleeding could occur as a result of low blood cell levels. Contact your doctor immediately if you experience fever, chills, persistent sore throat, or any other sign of infection, or unusual bruising or bleeding.

Tositumomab is used for:

Treating certain forms of non-Hodgkin lymphoma in patients who have not responded to other therapy.

Tositumomab is a monoclonal antibody protein. It works by killing cancer cells.

Do NOT use tositumomab if:

  • you are allergic to any ingredient in tositumomab
  • you have severe anemia, low white blood cell counts (neutropenia), or low blood platelet counts (thrombocytopenia)
  • you are unable to take a thyroid blocker (eg, methimazole)

Contact your doctor or health care provider right away if any of these apply to you.

Before using tositumomab:

Some medical conditions may interact with tositumomab. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

  • if you are pregnant, planning to become pregnant, or are breast-feeding
  • if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
  • if you have allergies to medicines, foods, or other substances (eg, mouse proteins)
  • if you have an infection, kidney problems, urinary blockage, or thyroid problems
  • if you are scheduled to receive a vaccine

Some MEDICINES MAY INTERACT with tositumomab. Tell your health care provider if you are taking any other medicines, especially any of the following:

  • Medicines that decrease blood clotting (eg, aspirin, clopidogrel, ibuprofen, warfarin) and medicines that affect the immune system (eg, azathioprine, corticosteroids, cyclosporine) because serious side effects, such as risk of bleeding or infections, may be increased

This may not be a complete list of all interactions that may occur. Ask your health care provider if tositumomab may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use tositumomab:

Use tositumomab as directed by your doctor. Check the label on the medicine for exact dosing instructions.

  • Tositumomab is usually administered as an injection at your doctor's office, hospital, or clinic. Ask your doctor any question that you may have about tositumomab.
  • To help prevent an allergic reaction, you should receive certain other medicines (acetaminophen, diphenhydramine) before you receive your dose of tositumomab. Discuss any questions or concerns with your doctor.
  • Do not use tositumomab if it contains particles, is cloudy or discolored, or if the vial is cracked or damaged.
  • Keep this product, as well as syringes and needles, out of the reach of children and pets. Do not reuse needles, syringes, or other materials. Ask your health care provider how to dispose of these materials after use. Follow all local rules for disposal.
  • If you miss a dose of tositumomab, contact your doctor right away.

Ask your health care provider any questions you may have about how to use tositumomab.

Important safety information:

  • Tositumomab may cause dizziness or drowsiness. Do not drive, operate machinery, or do anything else that could be dangerous until you know how you react to tositumomab. Using tositumomab alone, with certain other medicines, or with alcohol may lessen your ability to drive or perform other potentially dangerous tasks.
  • Tositumomab may reduce the number of clot-forming cells (platelets) in your blood. Avoid activities that may cause bruising or injury. Tell your doctor if you have unusual bruising or bleeding. Tell your doctor if you have dark, tarry, or bloody stools.
  • Tositumomab may lower the ability of your body to fight infection. Avoid contact with people who have colds or infections. Tell your doctor if you notice signs of infection like fever, sore throat, rash, or chills.
  • Do not receive a live vaccine (eg, measles, mumps, oral polio) while you are taking tositumomab. Talk with your doctor before you receive any vaccine.
  • A serious bone marrow problem (myelodysplastic syndrome [MDS]) and secondary cancer have been reported with tositumomab. Discuss the benefits and risks of using tositumomab with your doctor.
  • Tell your doctor or dentist that you take tositumomab before you receive any medical or dental care, emergency care, or surgery.
  • Tositumomab may reduce the levels of thyroid hormone your thyroid produces. To prevent low thyroid function, you should also take a thyroid blocker medicine (eg, methimazole) while receiving tositumomab. Take the thyroid blocker medicine as directed by your doctor. Discuss any questions or concerns with your doctor.
  • Some patients may develop an immune response called human anti-murine antibody (HAMA) after using tositumomab. This antibody may interfere with certain lab test results. Be sure all of your doctors and laboratory personnel know that you are being treated, or have been treated, with tositumomab.
  • Both men and women capable of having children who receive tositumomab should use effective birth control (eg, condoms) while receiving tositumomab and for at least 1 year after receiving it. Contact your doctor if you have questions about effective birth control.
  • Tositumomab may cause temporary decreased fertility in men and women. Discuss any questions or concerns with your doctor.
  • LAB TESTS, including complete blood cell counts and thyroid function tests, will be performed while you use tositumomab and following treatment. These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
  • Tositumomab should be used with extreme caution in CHILDREN; safety and effectiveness in children have not been confirmed.
  • PREGNANCY and BREAST-FEEDING: Tositumomab may cause harm to the fetus, including low thyroid function. Avoid becoming pregnant while you are taking it. If you become pregnant while taking tositumomab or after you have recently received it, contact your doctor. You will need to discuss the benefits and risks of using tositumomab while you are pregnant. Tositumomab is most likely excreted in breast milk. Do not breast-feed while receiving tositumomab or after you have recently received it.

Possible side effects of tositumomab:

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Back pain; constipation; diarrhea; dizziness; drowsiness; headache; muscle or joint pain; nausea; neck pain; stomach pain; stomach upset; vomiting; weakness.

Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, throat, or tongue; unusual hoarseness); chest pain; dark, tarry, or bloody stools; fainting; flushing of the skin; light-headedness; loss of appetite; pale skin; open sore that does not heal; pain, swelling, or redness at the injection site; severe or persistent dizziness or nausea; shortness of breath; swelling of the hands, ankles, or feet; symptoms of infection (eg, fever; chills; persistent cough or sore throat; red, warm, or painful skin; runny nose); unexplained weight loss; unusual bruising or bleeding; unusual lumps or skin growths; unusual sweating; unusual tiredness or weakness; vomit that looks like coffee grounds.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. To report side effects to the appropriate agency, please read the Guide to Reporting Problems to FDA.

If OVERDOSE is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center, or emergency room immediately. Symptoms may include symptoms of infection (eg, fever; chills; persistent cough or sore throat; red, warm, or painful skin; runny nose); unusual bruising or bleeding; unusual tiredness or weakness.

Proper storage of tositumomab:

Tositumomab is usually handled and stored by a health care professional. Keep tositumomab out of reach of children and away from pets.

General information:

  • If you have any questions about tositumomab, please talk with your doctor, pharmacist, or other health care provider.
  • Tositumomab is to be used only by the patient for whom it is prescribed. Do not share it with other people.
  • If your symptoms do not improve or if they become worse, check with your doctor.
  • Check with your pharmacist about how to dispose of unused medicine.

This information should not be used to decide whether or not to take tositumomab or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about tositumomab. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to tositumomab. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using tositumomab.

Issue Date: June 3, 2015