Cetuximab is administered through an intravenous (IV) infusion. The first dose is given as a loading dose to ensure maximum therapeutic effect. Subsequent doses are given on a weekly basis as part of a long-term treatment plan.

1. Loading dose:
   • Administered as a slow IV infusion over 120 minutes (2 hours) to assess the patient’s tolerance.
2. Maintenance doses:
   • Administered once a week after the loading dose, at a slower infusion rate depending on the patient’s tolerance and the clinician’s recommendation.

During the infusion, the healthcare provider will monitor the patient closely for any signs of allergic reactions or infusion-related reactions. If no severe reactions occur after the first dose, the infusion rate may be increased for subsequent doses.

Cetuximab works by selectively binding to the extracellular domain of the epidermal growth factor receptor (EGFR) on cancer cells. EGFR is involved in the signal transduction pathways that promote cell growth, survival, and proliferation. Under normal conditions, the binding of EGF or TGF-α to EGFR activates these pathways, which trigger cellular responses such as cell division and tumor progression.

In many cancers, particularly in colorectal and head and neck cancers, EGFR is overexpressed or abnormally activated, leading to excessive cell growth and tumor development. Cetuximab binds to EGFR and prevents its activation, thereby blocking the downstream signaling that would otherwise promote cancer cell growth.

Cetuximab has two key effects on the cancer cells:

1. Inhibition of tumor growth: By blocking EGFR activation, Cetuximab can reduce or halt the proliferation of cancer cells.
2. Induction of cell death: Cetuximab can trigger antibody-dependent cell-mediated cytotoxicity (ADCC), where the immune system’s natural killer cells attack and kill the cancer cells that are bound by the antibody.

In addition to its action on cancer cells, Cetuximab can also enhance the effectiveness of certain chemotherapy drugs by making cancer cells more sensitive to treatment.

Common side effects of Cetuximab include:

• Skin reactions: These are the most common side effects and include acne-like rashes, itching, and dry skin.
• Infusion reactions: Some patients may experience fever, chills, nausea, and difficulty breathing during or after the infusion.
• Gastrointestinal issues: Diarrhea, nausea, and vomiting may occur in some patients.
• Fatigue: Many patients feel fatigued or weak during treatment with Cetuximab.
• Electrolyte imbalances: Cetuximab may cause low magnesium and low calcium levels in the blood, which can lead to muscle cramps, weakness, or heart problems.

• Allergic reactions: Cetuximab can cause severe allergic reactions, especially during the first infusion. Patients must be closely monitored during the initial dose for signs of anaphylaxis or other serious reactions.
• Pregnancy and breastfeeding: Cetuximab should not be used during pregnancy or breastfeeding, as it may harm the developing fetus or infant.
• KRAS mutations: Cetuximab is not effective in patients with certain mutations in the KRAS gene, which is found in some colorectal cancers. Testing for KRAS mutations is recommended before starting treatment.

Cetuximab may interact with certain medications, especially those that affect the immune system or are used in cancer treatment. These include:

• Chemotherapy drugs: Cetuximab is often used in combination with chemotherapy agents such as 5-fluorouracil (5-FU) and irinotecan for the treatment of metastatic colorectal cancer. The combination may have an enhanced effect compared to either agent used alone.
• Radiation therapy: Cetuximab can be combined with radiotherapy in the treatment of head and neck cancers. The combination of Cetuximab and radiation may improve treatment outcomes.
• Other monoclonal antibodies: Cetuximab is sometimes combined with other monoclonal antibodies in cancer treatment regimens, though careful monitoring is required for potential immune-related reactions.

It is important to inform your healthcare provider about all medications you are taking, including prescription drugs, over-the-counter medications, and supplements, to avoid any potential interactions.

• For oral tablets: Usually taken once daily, with or without food.
• For transdermal patches: Apply to clean, dry skin, and replace every three to four days.
• Do not crush or chew the tablets; swallow them whole with water.
• If you miss a dose, take it as soon as you remember, but skip it if it is almost time for the next dose.

Cetuximab is a prescription medication and must be administered under the supervision of a healthcare provider experienced in cancer treatment. A specialized oncologist will determine the appropriate dosage and schedule based on the type of cancer and the patient’s overall health.

1. What is Cetuximab?
   A monoclonal antibody used to treat certain cancers by blocking the epidermal growth factor receptor (EGFR).

2. What cancers does Cetuximab treat?
   Commonly used in colorectal cancer, head and neck squamous cell carcinoma.

3. How does Cetuximab work?
   It binds to EGFR on cancer cells, inhibiting growth and survival signals.

4. How is Cetuximab given?
   By intravenous infusion in a clinical setting.

5. How often is Cetuximab administered?
   Typically once weekly or biweekly, depending on the regimen.

6. Can I receive Cetuximab at home?
   No, it requires administration by a healthcare professional.

7. What are common side effects?
   Rash, infusion reactions, diarrhea, fatigue, and low magnesium levels.

8. What infusion reactions can occur?
   Severe allergic reactions like difficulty breathing, itching, or swelling may occur.

9. Is premedication needed before Cetuximab?
   Yes, usually antihistamines and sometimes corticosteroids to reduce infusion reactions.

10. Can Cetuximab be combined with other cancer treatments?
    Yes, often given with chemotherapy or radiation.

11. Are there any contraindications?
    Patients with severe hypersensitivity to Cetuximab or murine proteins should avoid it.

12. Can Cetuximab be used in all colorectal cancer cases?
    It is effective only in tumors without certain KRAS mutations.

13. What monitoring is needed during treatment?
    Regular blood tests and skin exams are important.

14. Can Cetuximab cause skin problems?
    Yes, acne-like rash is common and can be severe.

15. How long does a typical treatment last?
    Duration depends on response and tolerance, often several months.

16. Is Cetuximab safe during pregnancy?
    Its safety has not been established; avoid use during pregnancy.

17. Can Cetuximab affect fertility?
    Potentially, discuss concerns with your doctor.

18. What should I do if I miss a dose?
    Contact your healthcare provider for instructions.

19. How should Cetuximab be stored?
    Stored refrigerated and protected from light.

20. Is Cetuximab covered by insurance?
    Many insurance plans cover it, but check individual policies.