Erbitux Cetuximab Injection

1. Indications and Usage
Metastatic Colorectal Cancer (mCRC): Indicated for the treatment of K-Ras wild-type, EGFR-expressing mCRC in combination with FOLFIRI for first-line treatment; in combination with irinotecan in patients refractory to irinotecan-based chemotherapy; or as a single agent in patients who have failed both oxaliplatin- and irinotecan-based regimens or who are intolerant to irinotecan.
BRAF V600E Mutant mCRC: In combination with encorafenib for adults with mCRC with a BRAF V600E mutation, as detected by an FDA-approved test, after prior therapy.
Squamous Cell Carcinoma of the Head and Neck (SCCHN): In combination with radiation therapy for the initial treatment of locally or regionally advanced SCCHN; in combination with platinum-based therapy and fluorouracil for recurrent or metastatic SCCHN; or as a single agent for recurrent or metastatic SCCHN after failure of platinum-based therapy.
Limitation of Use: Not indicated for the treatment of patients with colorectal cancer harboring somal mutations in KRAS or NRAS (exons 2, 3, and 4) or when RAS mutation status is unknown.
2. Dosage and Administration
Patient Selection: Confirm RAS wild-type status and EGFR expression (for mCRC) or BRAF V600E mutation status (for BRAF-mutant mCRC) using an FDA-approved test prior to initiation.
Premedication: Administer an H1 antagonist (e.g., diphenhydramine) prior to the first infusion. Premedication is recommended before all subsequent infusions.
Recommended Dose:
Weekly Regimen: Initial dose of 400 mg/m² IV over 120 minutes (max infusion rate 5 mg/min), followed by 250 mg/m² IV weekly over 60 minutes (max infusion rate 10 mg/min).
Biweekly Regimen: 500 mg/m² IV every 2 weeks over 120 minutes.
Administration: Administer via IV infusion using a low-protein-binding 0.22-micrometer in-line filter. Do not administer as an IV push or bolus. Complete administration 1 hour prior to irinotecan or FOLFIRI.
Dose Modifications: Reduce infusion rate by 50% for Grade 1–2 infusion reactions or non-serious Grade 3–4 reactions. Permanently discontinue for serious infusion reactions. Withhold or reduce dose for severe acneiform rash.
3. Mechanism of Action
Cetuximab is a recombinant, human/mouse chimeric IgG1 monoclonal antibody that binds specifically to the extracellular domain of the epidermal growth factor receptor (EGFR, HER1, c-ErbB-1) on both normal and tumor cells. It competitively inhibits the binding of epidermal growth factor (EGF) and other ligands such as transforming growth factor-alpha (TGF-α), blocking phosphorylation and activation of receptor-associated kinases. This inhibits cell growth, induces apoptosis, decreases matrix metalloproteinase and vascular endothelial growth factor (VEGF) production, and mediates antibody-dependent cellular cytotoxicity (ADCC).
4. Safety and Warnings
Boxed Warning:
Infusion Reactions: Serious and potentially fatal infusion reactions occur in approximately 3% of patients. Immediately interrupt and permanently discontinue for serious reactions.
Cardiopulmonary Arrest: Cardiopulmonary arrest and/or sudden death occurred in 2% of SCCHN patients receiving cetuximab with radiation therapy and in 3% receiving cetuximab with platinum-based therapy and fluorouracil. Monitor serum electrolytes (magnesium, potassium, calcium) during and after treatment.
Dermatologic Toxicity: Acneiform rash occurs in up to 90% of patients. Advise patients to limit sun exposure.
Pulmonary Toxicity: Interstitial lung disease (ILD) has been reported. Withhold and investigate if ILD is suspected; permanently discontinue if confirmed.
Hypomagnesemia: Can occur during and up to 8 weeks after completion of treatment. Monitor magnesium levels periodically.
Embryo-Fetal Toxicity: May cause fetal harm. Advise females and males with female partners of reproductive potential to use effective contraception during treatment and for 6 months after the last dose.
5. Adverse Reactions and Clinical Research
Common Adverse Reactions (≥20%): Acneiform rash, asthenia/malaise, diarrhea, nausea, hypomagnesemia, weight loss, constipation, dry skin, pruritus, radiation dermatitis, neutropenia, fatigue, headache, and dyspnea.
Serious Adverse Reactions: Infusion reactions, cardiopulmonary arrest, ILD, severe dermatologic toxicity, sepsis, and renal failure.
Clinical Research: Efficacy was established in multiple randomized trials. In mCRC, cetuximab improved overall survival and progression-free survival in RAS wild-type patients. In SCCHN, cetuximab plus radiation significantly improved overall survival compared with radiation alone, and cetuximab plus platinum/5-FU improved response rates compared with chemotherapy alone.
6. Drug Interactions
Chemotherapy Agents: No pharmacokinetic interactions were observed between cetuximab and irinotecan, cisplatin, or carboplatin.
Radiation Therapy: Concomitant use may increase the risk of radiation dermatitis and cardiopulmonary events in SCCHN patients.
Live Vaccines: Avoid administration of live vaccines during treatment.
7. Pharmaceutical Information
Active Ingredient: Cetuximab.
Drug Class: Epidermal growth factor receptor (EGFR) antagonist; recombinant human/mouse chimeric IgG1 monoclonal antibody.
Strengths: 100 mg/50 mL (2 mg/mL) and 200 mg/100 mL (2 mg/mL) single-dose vials.
Description: Clear, colorless, preservative-free solution for IV infusion.
Inactive Ingredients: Sodium chloride, glycine, polysorbate 80, citric acid monohydrate, and water for injection.
Storage: Store refrigerated at 2°C to 8°C (36°F to 46°F) in the original carton to protect from light. Do not freeze or shake.