Erbitux (cetuximab) is a targeted cancer medicine given by intravenous (IV) infusion. It is a monoclonal antibody that targets a protein called EGFR (epidermal growth factor receptor), which is found on the surface of some cancer cells and helps them grow.

Erbitux is used to treat:

• Metastatic colorectal cancer that has RAS wild-type (no RAS mutation), either alone, in combination with chemotherapy, or as part of a targeted therapy combination including Braftovi (for BRAF V600E-mutant disease)
• Squamous cell carcinoma of the head and neck (SCCHN), in combination with radiation therapy for locally advanced disease, or with chemotherapy for recurrent or metastatic disease

How it works:

EGFR sits on the surface of some cancer cells and receives signals that tell them to grow and divide. Cetuximab binds to EGFR and blocks these signals, slowing cancer cell growth. It also flags the cancer cells for destruction by the immune system.

Your dose and schedule:

Erbitux is administered by a healthcare professional as an IV infusion at a hospital or cancer centre. It is given once weekly or every two weeks, depending on the treatment regimen. Your oncologist will outline the full schedule for you.

Before each infusion:

• You will receive pre-medications (antihistamines and corticosteroids) before your first infusion and often before subsequent infusions to reduce the risk of infusion reactions
• Tell your doctor about all medicines, vitamins, and supplements you take
• Let your doctor know if you have any history of heart problems, particularly low magnesium levels

Before you start:

• For colorectal cancer, your tumour will be tested for RAS mutations before starting, as Erbitux is only effective in RAS wild-type (non-mutated) tumours
• Tell your doctor if you are pregnant or planning to become pregnant

Erbitux is given by your healthcare team.

If you need to reschedule an appointment:

• Contact your oncology team as soon as possible to rebook
• Try not to delay infusions for long, as consistency is important for treatment effectiveness

Infusion-related reactions are the most significant concern.

These can include:

• Mild: Fever, chills, nausea, headache
• Severe: Difficulty breathing, sudden drop in blood pressure, severe skin reactions

Severe reactions can occur during the first infusion and are rarer with later ones. Your care team will monitor you closely throughout and are prepared to manage any reaction promptly. Tell your nurse immediately if you notice any symptoms.

Erbitux is stored and prepared by your hospital or infusion centre. No home storage is required.

Side effects are common.

The most important ones to know about are:

• Skin reactions (acneiform rash): A pimple-like rash on the face, neck, and upper body is the most common side effect of Erbitux, affecting most people. Interestingly, a more prominent rash is sometimes associated with better treatment response. Your care team will advise on skin care. Avoid sun exposure and use sunscreen
• Infusion-related reactions: Particularly with the first infusion. Pre-medications help manage this
• Low magnesium (hypomagnesaemia): EGFR inhibitors can cause the kidneys to lose magnesium. Your magnesium levels will be monitored and supplements prescribed if needed
• Fatigue: Very common
• Diarrhoea: Particularly common when Erbitux is combined with chemotherapy
• Nail changes: Inflammation around the fingernails or toenails (paronychia) is a recognised side effect

Contact your oncology team if any side effect concerns you.

Tell your doctor and pharmacist everything you are taking.

Key considerations:

• Chemotherapy: Erbitux is often combined with oxaliplatin- or irinotecan-based chemotherapy. Your oncologist will manage any combined side effects
• Live vaccines: Avoid live vaccines during treatment
  

Never start, stop, or change any medicine without speaking to your doctor first.

What does RAS wild-type mean for colorectal cancer?

RAS is a gene that, when mutated, causes cancer cells to grow independently of EGFR signals. If your tumour has a RAS mutation, blocking EGFR with Erbitux will not stop cancer growth because the cancer has already bypassed this pathway. RAS wild-type means your tumour does not have this mutation, making it likely to respond to Erbitux. This is why testing is done before starting treatment.

What should I do about the rash?

The skin rash caused by EGFR inhibitors like Erbitux is almost universal and can be distressing. Your care team will provide guidance on skin care, which typically includes gentle cleansers, regular moisturising, avoiding sun exposure, using sunscreen, and sometimes topical or oral antibiotics. Tell your team if the rash becomes painful, infected, or is significantly affecting your quality of life, as dose adjustments may be considered.

Ace provides accurate and independent information medically reviewed on prescription medications. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment.