Safety Profile

What possible side effects may I have after getting BEXXAR?¹

Like other therapies for follicular non-Hodgkin’s lymphoma, patients may experience side effects during or after treatment with BEXXAR. If this happens, it’s important to know what these side effects might be, and what can be done to treat them.

Before receiving BEXXAR, your doctor will give you medicine that may prevent or reduce side effects that may happen during your IV infusion. During your infusion, you’ll be monitored by your doctor to see if you develop any side effects, since there is a possibility that you could have a serious allergic reaction to BEXXAR. If this happens, your doctor will stop the infusion and give you medicine to treat the allergic reaction. In some cases, these reactions have been fatal.

Other side effects that may happen during or after your infusion of BEXXAR include fever, chills, sweating, nausea, low blood pressure, shortness of breath, and wheezing. These side effects can usually be helped by slowing down how fast you get the infusion, or by stopping the infusion for a little while and then starting it again when you feel better.

After treatment with BEXXAR, it is likely you will experience a delayed and temporary decrease in the number of healthy white blood cells, red blood cells, and platelets in your bloodstream, a serious condition called cytopenia. Too few white blood cells make it harder for you to fight infections, and these infections can become serious. Too few red blood cells cause anemia, which can make you feel tired and weak. Too few platelets can cause serious bleeding, which may be hard to stop once it has started. The blood counts are usually lowest between 4 and 7 weeks after your last dose of BEXXAR.

If you do experience a prolonged or serious decrease in red blood cells or platelets, you may need a blood transfusion to get your blood cell counts back to normal to help you feel better. If you experience a decrease in white blood cells, your doctor may give you a medicine to increase your white blood cell count.

Your body will soon make new blood cells, but because having too few healthy blood cells can be serious and even life threatening, your doctor will take blood samples for 10 to 12 weeks or longer after treatment to make sure your blood cell counts are returning to normal. In some patients, low blood cell counts can last up to 90 days or longer.

Other side effects that you may experience include but are not limited to weakness, fever, nausea, infection, increased cough, and pain. After treatment with BEXXAR, less than 5% of patients lost their hair, had severe nausea and vomiting, or had sores in their mouth or stomach.

Sometimes side effects can take months or years to appear. Some patients have developed leukemia (cancer of the blood), myelodysplastic syndrome (a condition that may develop into leukemia), or cancer of other body organs. It’s not known whether the risk of developing cancer after treatment with BEXXAR is higher than the rate of cancer that occurs in people who haven’t had treatment with BEXXAR.

WARNINGS ¹

Treatment with BEXXAR does involve risk.

Serious Allergic Reaction: Patients may develop serious allergic reactions with the intravenous (IV) infusion of BEXXAR. In some cases, death has been reported. Medications for the treatment of severe reactions should be available for immediate use by a physician. Patients who develop severe reactions should have the infusion of BEXXAR stopped and receive appropriate medical attention.

Low Blood Counts: Most patients who received BEXXAR developed prolonged and severe low blood counts. This can lead to serious infections or bleeding problems.

Not for Pregnant Women: BEXXAR can harm a fetus when given to a pregnant woman.

Special Requirements: BEXXAR contains radioactive material and should be administered only by physicians and other healthcare workers who are qualified by training in the safe use and handling of radioactive materials.

IMPORTANT SAFETY INFORMATION¹

Not for Everyone: Not all patients are candidates for treatment with BEXXAR. Patients with a known prior reaction to a mouse protein, or any other part of BEXXAR, should not be given BEXXAR. Patients with more than one quarter of their bone marrow space occupied by lymphoma cells, patients with a low bone marrow reserve, or women who are pregnant should also not be treated with BEXXAR.

Low Blood Counts: The most common early side effects were very low blood counts in 71% of the patients. The lowest counts usually occurred around 4-7 weeks after the first dose of BEXXAR and lasted about a month. Your doctor should check your blood (a CBC) weekly, or more often, until your counts recover. Because of low counts your doctor might also ask you to take some precautions against infection or bleeding. Infections occurred in approximately half of the patients (serious infections in 9% of 230). Bleeding occurred in 12% of patients. Most of these cases were mild to moderate. About one quarter of the patients required drugs or blood transfusions during this period to help their counts recover.

Development of Allergy: In 10% to 11% of patients, administration of BEXXAR resulted in development of antibodies to the mouse protein in BEXXAR, which their bodies considered to be a foreign protein. These antibodies go by the name HAMA (human anti-mouse antibody). If a person makes HAMA, they could have a serious allergic reaction to any other drug or diagnostic test that was made from mouse protein or it could affect how well the drug or diagnostic test worked.

Development of Other Cancer: Ten percent of patients (98 of 995) developed a second cancer: 44 patients had preleukemia and/or leukemia and 54 patients had other cancers (65 cases). Approximately half of these were skin cancers and the others, in decreasing frequency, which occurred in 2 or more patients, included colorectal cancer, head and neck cancer, breast cancer, lung cancer, bladder cancer, melanoma, and gastric cancer. Whether there is an increased risk of developing another cancer after BEXXAR is difficult to determine since a group of similar patients who did not receive BEXXAR was not evaluated.

Thyroid Problems: In 13% to 18% of patients, treatment with BEXXAR resulted in hypothyroidism (lowered production of thyroid hormone or receiving thyroid replacement therapy). All patients are given medication prior to and during treatment with BEXXAR to attempt to block the uptake of the radioactive iodine part of BEXXAR by the thyroid gland. Patients who cannot tolerate this medication should not be given BEXXAR. After treatment, patients should be seen by their physicians yearly for signs and symptoms of hypothyroidism and screened with a blood test. Hypothyroidism is treated by taking a daily pill to replace thyroid hormone.

Problems with Infusion: Side effects experienced during or following the infusion of BEXXAR include fever, chills, sweating, nausea, low blood pressure, shortness of breath, and wheezing. Twenty-nine percent of patients reported fever, chills, or sweating following the first dose. Most side effects were managed by slowing or stopping the related infusion for a time. In 2 patients, the infusion had to be stopped and the patients did not receive all of the drug.

Distribution of BEXXAR: After infusion of the dosimetric dose, the distribution of BEXXAR in your body will be reviewed using 3 scans over 7 days, and if the distribution is not normal, your doctor may decide not to administer the therapeutic dose.

Other: BEXXAR may result in other side effects. Please see the Prescribing Information (PI) for more information about the Warnings, Contraindications, and Adverse Events for BEXXAR.

Complete Prescribing Information for
BEXXAR (Tositumomab and Iodine I 131 Tositumomab)

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