Cetuximab

Cetuximab is a recombinant human/mouse chimeric monoclonal antibody. It binds specifically to the epidermal growth factor receptor (EGFR), thus competitively inhibiting the binding of epidermal growth factor (EGF) and other ligands. This blocks phosphorylation and activation of receptor-associated kinases, thus inhibiting cell growth, inducing apoptosis and decreases matrix metalloproteinase and vascular EGF production.

Squamous Cell Carcinoma Of The Head And Neck:

Cetuximab in combination with radiation therapy or in combination with platinum-based therapy with 5-FU:

• The recommended initial dose is 400 mg/m² administered one week prior to initiation of a course of radiation therapy or on the day of initiation of platinum-based therapy with 5-FU as a 120-minute intravenous infusion (maximum infusion rate 10 mg/min). Complete Cetuximab administration 1 hour prior to platinum-based therapy with 5-FU.
• The recommended subsequent weekly dose (all other infusions) is 250 mg/m² infused over 60 minutes (maximum infusion rate 10 mg/min) for the duration of radiation therapy (6–7 weeks) or until disease progression or unacceptable toxicity when administered in combination with platinum-based therapy with 5-FU. Complete Cetuximab administration 1 hour prior to radiation therapy or platinumbased therapy with 5-FU.

Cetuximab monotherapy:

• The recommended initial dose is 400 mg/m² administered as a 120-minute intravenous infusion (maximum infusion rate 10 mg/min).
• The recommended subsequent weekly dose (all other infusions) is 250 mg/m² infused over 60 minutes (maximum infusion rate 10 mg/min) until disease progression or unacceptable toxicity.

Colorectal Cancer:

• Determine EGFR-expression status using FDA-approved tests prior to initiating treatment. Also confirm the absence of a Ras mutation prior to initiation of treatment with Cetuximab. 
• The recommended initial dose, either as monotherapy or in combination with irinotecan or FOLFIRI (irinotecan, 5-fluorouracil, leucovorin), is 400 mg/m² administered as a 120-minute intravenous infusion (maximum infusion rate 10 mg/min). Complete Cetuximab administration 1 hour prior to FOLFIRI.
• The recommended subsequent weekly dose, either as monotherapy or in combination with irinotecan or FOLFIRI, is 250 mg/m² infused over 60 minutes (maximum infusion rate 10 mg/min) until disease progression or unacceptable toxicity. Complete Cetuximab administration 1 hour prior to FOLFIRI.

Recommended Premedication: Premedicate with an H1 antagonist (eg, 50 mg of diphenhydramine) intravenously 30–60 minutes prior to the first dose; premedication should be administered for subsequent Cetuximab doses based upon clinical judgment and presence/severity of prior infusion reactions.

Do not administer cetuximab as an intravenous push or bolus. Administer via infusion pump or syringe pump. Do not exceed an infusion rate of 10 mg/min. Administer through a low protein binding 0.22-micrometer in-line filter.

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. The solution should be clear and colorless and may contain a small amount of easily visible, white, amorphous, cetuximab particulates. Do not s hake or dilute.

Fatigue, pain, headache, fever, confusion, anxiety, insomnia, chills, rigors, depression. Acneiform rash, rash, dry skin, pruritus, nail changes, hypomagnesaemia, abdominal pain, constipation, diarrhoea, vomiting, nausea, wt loss, weakness, bone pain.

Pregnancy: category C. Either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocidal or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the fetus.

Nursing Mothers: It is not known whether Cetuximab is secreted in human milk. IgG antibodies, such as Cetuximab, can be excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from Cetuximab, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother. If nursing is interrupted, based on the mean half-life of cetuximab, nursing should not be resumed earlier than 60 days following the last dose of Cetuximab.

Infusion rate should be reduced if patient exhibits signs of toxicity. Discontinue treatment if there is severe infusion reactions. Caution when used in patients with history of coronary artery disease, heart failure and arrhythmias. Monitor serum electrolytes during and after (for at least 8 wk) cetuximab therapy. Exposure to sunlight may worsen skin reactions. Risk of interstitial lung disease in patients with preexisting lung disease. Dose should be modified if there is occurrence of severe acneiform rash, refer to product insert/SPG for dosing guidelines.

Dose modification in cases of severe acneiform rash (grade 3 or 4):

• 1st occurrence: Delay infusion by 1-2 wk. If improvement, continue at 250 mg/m²; discontinue if no improvement.
• 2nd occurrence: Delay infusion by1-2 wk. If improvement, continue at reduced dose of 200 mg/m²; discontinue if no improvement.
• 3rd occurrence: Delay infusion by 1-2 wk. If improvement, continue at reduced dose of 150 mg/m²; discontinue if no improvement. 4th occurrence: Discontinue therapy.

The maximum single dose of cetuximab administered is 1000 mg/m² in one patient. No adverse events were reported for this patient.

Targeted Cancer Therapy

Store vials under refrigeration at 2° to 8° C. Do not freeze.