Tositumomab and iodine I-131

Tositumomab and iodine-131
Mechanism of action	Monoclonal antibody that targets the CD20+ protein on the B cell in follicular non-Hodgkin lymphoma and carries with it iodine-131 to induce cell death
Dose	Single treatment course consisting of two steps: Dosimetric dose: Tositumomab 450 mg IV over 60 minutes Iodine-131 5 mCi, tositumomab 35 mg IV over 20 minutes Allows for individualized dosing. Nonradioactive tositumomab administered via IV injection followed by trace amount of radioactive I-131 to evaluate clearance of radiation from patient. Gamma scan is performed immediately following and at two and four days following dosimetric dose. Therapeutic dose: Tositumomab 450 mg IV over 60 minutes. Iodine-131 at precalculated dose and 35 mg tositumomab IV over 20 minutes. Tositumomab labeled with Iodine I-131 dose as determined by dosimetric dose given 7–14 days following dosimetric dose. Physician must be certified in initial dose determinations before calculating doses independently.
Indications	Indicated for the treatment of patients with CD20+ follicular non-hodgkin's lymphoma with or without transformation whose disease is refractory to rituximab and has relapsed following chemotherapy.
Side Effects	Potentially severe and prolonged myelosuppression, infusion-related reaction, asthenia, nausea, cough, fever, and rash.
Nursing Considerations	Dosimetric dose may be given outside of the nuclear medicine or radiation oncology department. Therapeutic dose is given in nuclear medicine or the radiation oncology department. Infusion rate may need to be decreased to treat infusion-related reaction. Also, patients require written instructions on radiation safety precautions to follow for several days after receiving therapeutic dose to minimize exposure to people who are in their immediate vicinity. Radioactivity of patient is negligible, but patient is cautioned to avoid close contact for a specified period of time. Thyroid medications must be given one day prior to the start of the dosimetric dose and continued for 14 days following the therapeutic dose to avoid hypothyroidism. Perform baseline complete blood counts with differential and weekly for 10 weeks or more after administration. Baseline and annual thyroid-stimulating hormone are recommended. Safety has not been established in patients with >25% lymphoma marrow involvement, platelet count <100,000 cells/mm³ or neutrophil count <1,500 cells/mm³.

Mechanism of action

Monoclonal antibody that targets the CD20+ protein on the B cell in follicular non-Hodgkin lymphoma and carries with it iodine-131 to induce cell death

Dose

Single treatment course consisting of two steps:

Dosimetric dose:

Tositumomab 450 mg IV over 60 minutes
Iodine-131 5 mCi, tositumomab 35 mg IV over 20 minutes
Allows for individualized dosing. Nonradioactive tositumomab administered via IV injection followed by trace amount of radioactive I-131 to evaluate clearance of radiation from patient. Gamma scan is performed immediately following and at two and four days following dosimetric dose.

Therapeutic dose:

Tositumomab 450 mg IV over 60 minutes. Iodine-131 at precalculated dose and 35 mg tositumomab IV over 20 minutes.
Tositumomab labeled with Iodine I-131 dose as determined by dosimetric dose given 7–14 days following dosimetric dose.
Physician must be certified in initial dose determinations before calculating doses independently.

Indications

Indicated for the treatment of patients with CD20+ follicular non-hodgkin's lymphoma with or without transformation whose disease is refractory to rituximab and has relapsed following chemotherapy.

Side Effects

Potentially severe and prolonged myelosuppression, infusion-related reaction, asthenia, nausea, cough, fever, and rash.

Nursing Considerations

Dosimetric dose may be given outside of the nuclear medicine or radiation oncology department. Therapeutic dose is given in nuclear medicine or the radiation oncology department.

Infusion rate may need to be decreased to treat infusion-related reaction. Also, patients require written instructions on radiation safety precautions to follow for several days after receiving therapeutic dose to minimize exposure to people who are in their immediate vicinity. Radioactivity of patient is negligible, but patient is cautioned to avoid close contact for a specified period of time.

Thyroid medications must be given one day prior to the start of the dosimetric dose and continued for 14 days following the therapeutic dose to avoid hypothyroidism. Perform baseline complete blood counts with differential and weekly for 10 weeks or more after administration. Baseline and annual thyroid-stimulating hormone are recommended.

Safety has not been established in patients with >25% lymphoma marrow involvement, platelet count <100,000 cells/mm³ or neutrophil count <1,500 cells/mm³.