ZEVALIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ZEVALIN (ZEVALIN).
Zevalin (ibritumomab tiuxetan) is a CD20-directed radiolabeled monoclonal antibody. The ibritumomab component binds to the CD20 antigen on B-lymphocytes, and the tiuxetan chelator delivers yttrium-90 beta radiation to induce cellular damage and apoptosis.
| Metabolism | Ibritumomab tiuxetan is a monoclonal antibody; metabolism is expected to involve catabolism to small peptides and amino acids. The radiolabel (yttrium-90) decays via beta emission with a half-life of 64 hours; no hepatic metabolism. |
| Excretion | Primarily hepatobiliary, with minimal renal elimination (<5% unchanged). The radiolabeled component (yttrium-90 or indium-111) decays via beta or gamma emission. Fecal excretion accounts for <10%. |
| Half-life | The monoclonal antibody component (ibritumomab) has a terminal elimination half-life of approximately 10.4 hours in patients with relapsed B-cell non-Hodgkin lymphoma. The radioisotope (90Y or 111In) follows the antibody kinetics. |
| Protein binding | Ibritumomab tiuxetan, the monoclonal antibody, is primarily bound to serum proteins including albumin and gamma globulins; total protein binding is approximately 90-95%. |
| Volume of Distribution | Volume of distribution (Vd) for the antibody is approximately 5 L, which corresponds to plasma volume. It does not extensively distribute into total body water due to its large molecular weight. |
| Bioavailability | Zevalin is administered only intravenously; bioavailability is 100% by the IV route. There is no oral bioavailability. |
| Onset of Action | Therapeutic effect typically observed within 4-6 weeks after a single dose; tumor response may be seen as early as 2 weeks in some cases. |
| Duration of Action | The duration of response varies; median duration of response in clinical trials was approximately 12 months (range 2-24+ months). Repeat dosing is not routinely recommended due to immunogenicity. |
Zevalin (ibritumomab tiuxetan) is administered as a two-step regimen: (1) Rituximab 250 mg/m2 IV infusion on Day 1, (2) Indium-111 ibritumomab tiuxetan 5 mCi (185 MBq) IV push over 10 minutes on Day 1 for imaging, followed by Yttrium-90 ibritumomab tiuxetan 0.4 mCi/kg (14.8 MBq/kg) IV push over 10 minutes on Day 7-9 (maximum dose 32 mCi). All doses are based on body surface area and weight.
| Dosage form | INJECTABLE |
| Renal impairment | Contraindicated in patients with creatinine clearance < 30 mL/min. No dose adjustment recommended for mild to moderate renal impairment (CrCl ≥ 30 mL/min), but caution advised due to limited data. |
| Liver impairment | No formal Child-Pugh based adjustments established. Use with caution in patients with hepatic impairment; consider dose reduction if severe hepatic dysfunction (e.g., bilirubin > 3 mg/dL) as drug exposure may increase. |
| Pediatric use | Safety and efficacy not established in pediatric patients. No recommended dosing available. |
| Geriatric use | No specific dose adjustment required based on age alone. Monitor for increased toxicity (e.g., myelosuppression) in elderly patients due to potential renal function decline and comorbidities. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ZEVALIN (ZEVALIN).
| Breastfeeding | It is unknown whether yttrium-90 ibritumomab tiuxetan is excreted in human milk. Due to potential for serious adverse effects in the breastfed infant (including radiation exposure and immunosuppression), breastfeeding is contraindicated during therapy and for at least 6 months after the last dose. No M/P ratio is available. |
| Teratogenic Risk | Yttrium-90 ibritumomab tiuxetan (Zevalin) is a radioactive agent. There are no adequate and well-controlled studies in pregnant women. Based on its mechanism of action and genotoxicity, it is likely to cause fetal harm if administered during pregnancy. First trimester exposure carries the highest risk for major structural anomalies; exposure in the second and third trimesters may cause fetal growth restriction, myelosuppression, and radiation-induced effects. Pregnancy should be avoided during and for 12 months after treatment. |
■ FDA Black Box Warning
WARNING: SERIOUS INFUSION REACTIONS, PROLONGED AND SEVERE CYTOPENIAS, AND SEVERE CUTANEOUS AND MUCOCUTANEOUS REACTIONS. Infusion reactions may be fatal; discontinue if severe. Severe and prolonged cytopenias (including neutropenia, thrombocytopenia, and anemia) occur in most patients; monitor blood counts. Severe cutaneous and mucocutaneous reactions (e.g., Stevens-Johnson syndrome, toxic epidermal necrolysis) have been reported; discontinue if such reactions occur.
| Serious Effects |
["Hypersensitivity to ibritumomab, tiuxetan, yttrium-90, or murine proteins","Concurrent use or recent use (within 6 weeks) of other radiopharmaceuticals or external beam radiation"]
| Precautions | ["Severe infusion reactions including anaphylaxis","Prolonged and severe cytopenias requiring monitoring of complete blood counts","Severe cutaneous and mucocutaneous reactions","Increased risk of secondary malignancies (e.g., myelodysplastic syndrome, acute myeloid leukemia)","Extravasation of the radiolabeled compound leading to tissue necrosis","Immunization with live vaccines not recommended during treatment","Fetal harm; advise women of reproductive potential to use effective contraception"] |
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| Fetal Monitoring | Monitor complete blood counts (CBCs) with differential and platelet counts weekly during therapy and for at least 12 weeks after treatment. Assess liver and renal function prior to and during treatment. In pregnant patients, fetal monitoring via ultrasound for growth and anatomy should be considered, and a radiation safety consultation is recommended to estimate fetal radiation dose. |
| Fertility Effects | Zevalin contains yttrium-90, a radioactive isotope, which can cause gonadal toxicity and impair fertility. Both male and female patients may experience reduced fertility due to radiation-induced damage to germ cells. Amenorrhea and azoospermia have been reported. Fertility preservation options should be discussed prior to treatment. |