CETUXIMAB

CETUXIMAB (ce-tux'i-mab) Erbitux Classifications: antineoplastic; monoclonal antibody; epidermal growth factor receptor (egfr) inhibitor; Therapeutic:antineoplastic; monoclonal antibody; egfr inhibitor Prototype: Gefitinib Pregnancy Category: C

Availability

100 mg/50 mL injection

Action

Cetuximab is a recombinant, monoclonal antibody that binds specifically to the epidermal growth factor receptor (EGFR, HER1, c-ErbB-1) on both normal and tumor cells. Binding to the EGFR results in inhibition of cell growth, induction of apoptosis, and decreased vascular endothelial growth factor production.

Therapeutic Effect

Overexpression of EGFR is detected in many human cancers, including those of the colon and rectum. Cetuximab inhibits the growth and survival of tumor cells that overexpress the EGFR.

Uses

Treatment of EGFR-expressing metastatic colorectal cancer in combination with irinotecan in patients who are refractory to irinotecan-based chemotherapy or as monotherapy in patients who are intolerant to irinotecan-based chemotherapy. Used in combination with radiation for squamous cell cancer of head and neck.

Contraindications

Pregnancy (category C), lactation within 60 d of using cetuximab; worsening of preexisting pulmonary edema or interstitial lung disease. Safety and efficacy in children have not been established.

Cautious Use

Infusion reaction, especially with first time users; history of hypersensitivity to murine proteins or cetuximab; cardiac disease, coronary artery disease; pulmonary disease, pulmonary fibrosis; UV exposure, radiation therapy.

Route & Dosage

Colorectal Cancer/Head and Neck Cancer Adult: IV Start with 400 mg/m2 over 2 h; continue with 250 mg/m2 over 1 h weekly

Administration

Intravenous Administer with full resuscitation equipment available and under the supervision of a physician experienced with chemotherapy. Premedication with an H1-receptor antagonist (e.g., diphenhydramine 50 mg IV) is recommended. Monitor for an infusion reaction for at least 1 h following completion of infusion. PREPARE: IV Infusion: Do not shake or further dilute vial. Do not mix with other medication. Inject cetuximab solution into a sterile, evacuated container or bag (i.e., glass, polyolefin, ethylene vinyl acetate, DEHP plasticized PVC, or PVC); repeat until needed dose has been added to container, using a new needle for each vial. Attach to infusion set with a low-protein-binding 0.22-micron filter and prime line with cetuximab. May also administer by syringe and syringe pump; use a new needle and filter for each vial.   ADMINISTER: IV Infusion: • Do NOT administer a bolus dose. Give IV infusion via an infusion pump or syringe pump at ≤5 mL/min; piggyback into the patient's IV line.• Flush line with NS after infusion.• Note: Slow infusion rate by 50% if a prior, mild infusion reaction occurred.  INCOMPATIBILITIES Solution/additive: Do not mix with other additives. Y-site: No data available.

• Store unopened vials at 2°–8° C (36°–46° F). Note: Vials may contain a small amount of easily visible, white particles.
• Cetuximab in IV bag is stable for up to 12 h refrigerated and up to 8 h at 20°–25° C (68°–77° F).

Adverse Effects (≥1%)

Body as a Whole: Infusion reactions (allergic reaction, anaphylactoid reaction, fever, chills, dyspnea, bronchospasm stridor, hoarseness, urticaria, hypotension), fever, sepsis, asthenia, malaise, pain, infection. CNS: Headache, insomnia, depression. CV: Cardiopulmonary arrest. GI: Nausea, vomiting, diarrhea, abdominal pain, constipation, stomatitis, dyspepsia. Hematologic: Leukopenia, anemia. Metabolic: Weight loss, peripheral edema, dehydration, hypomagnesemia, hypokalemia. Respiratory: Pulmonary embolism, pulmonary fibrosis (rare), dyspnea, cough. Skin: Rash, alopecia, pruritus. Urogenital: Kidney failure.

Interactions

Drug: None reported to date.

Pharmacokinetics

Half-Life: 114 h (75–188 h).

Nursing Implications

Assessment & Drug Effects

• Discontinue infusion and notify physician for S&S of a severe infusion reaction: chills, fever, bronchospasm, stridor, hoarseness, urticaria, and/or hypotension. Institute supportive measures immediately, including epinephrine, corticosteroids, IV antihistamines, bronchodilators, and oxygen. Carefully monitor until complete resolution of all S&S.
• Monitor pulmonary status and report onset of acute or worsening pulmonary symptoms.
• Lab tests: Periodic CBC with differential, Hct and Hgb.

Patient & Family Education

• Report immediately: especially difficulty breathing, wheezing, shortness of breath, hives, faintness and/or dizziness anytime during IV infusion.
• Report promptly any of the following: eye inflammation, mouth sores, skin rash, redness, or severe dry skin.
• Wear sunscreen and a hat and limit sun exposure while being treated with this drug.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug