Infusion-related, including anaphylactic, reactions: Severe infusion-related reactions, including anaphylactic reactions, may commonly occur, in some cases with fatal outcome. Occurrence of a severe infusion-related reactions requires immediate and permanent discontinuation of cetuximab therapy and may necessitate emergency treatment. Some of these reactions may be anaphylactic or anaphylactoid in nature or represent a cytokine release syndrome (CRS). Symptoms may occur during the first infusion and for up to several hours afterwards or with subsequent infusions. It is recommended to warn patients of the possibility of such a late onset and instruct them to contact their physician if symptoms or signs of an infusion-related reaction occur. Symptoms may include bronchospasm, urticaria, increase or decrease in blood pressure, loss of consciousness or shock. In rare cases, angina pectoris, myocardial infarction or cardiac arrest have been observed.
Anaphylactic reactions may occur as early as within a few minutes of the first infusion e.g. due to preformed IgE antibodies cross-reacting with cetuximab. These reactions are commonly associated with bronchospasm and urticaria. They can occur despite the use of premedication.
The risk for anaphylactic reactions is much increased in patients with a history of allergy to red meat or tick bites or positive results of tests for IgE antibodies against cetuximab (α-1-3 galactose). In these patients cetuximab should be administered only after a careful assessment of benefit/risk, including alternative treatments, and only under close supervision of well trained personnel with resuscitation equipment ready.
The first dose should be administered slowly and the speed must not exceed 5 mg/min whilst all vital signs are closely monitored for at least two hours. If during the first infusion, an infusion- related reaction occurs within the first 15 minutes, the infusion should be stopped. A careful benefit/risk assessment should be undertaken including consideration whether the patient may have performed IgE antibodies before a subsequent infusion is given.
If an infusion-related reaction develops later during the infusion or at a subsequent infusion further management will depend on its severity: Grade 1: continue slow infusion under close supervision, Grade 2: continue slow infusion and immediately administer treatment for symptoms, Grade 3 and 4: stop infusion immediately, treat symptoms vigorously and contraindicate further use of cetuximab.
A cytokine release syndrome (CRS) typically occurs within one hour after infusion and is less commonly associated with bronchospasm and urticaria. CRS is normally most severe in relation to the first infusion.
Mild or moderate infusion-related reactions are very common comprising symptoms such as fever, chills, dizziness, or dyspnoea that occur in a close temporal relationship mainly to the first cetuximab infusion. If the patient experiences a mild or moderate infusion-related reaction, the infusion rate may be decreased. It is recommended to maintain this lower infusion rate in all subsequent infusions.
A close monitoring of patients, particularly during the first administration, is required. Special attention is recommended for patients with reduced performance status and pre-existing cardio-pulmonary disease.
Respiratory disorders: Cases of interstitial lung disease (ILD), including fatal cases, have been reported, with the majority of patients from the Japanese population.
Confounding or contributing factors, such as concomitant chemotherapy known to be associated with ILD, and pre-existing pulmonary diseases were frequent in fatal cases. Such patients should be closely monitored. In the event of symptoms (such as dyspnoea, cough, fever) or radiographic findings suggestive of ILD, prompt diagnostic investigation should occur.
If interstitial lung disease is diagnosed, cetuximab must be discontinued and the patient be treated appropriately.
Skin reactions: Main adverse reactions of cetuximab are skin reactions which may become severe, especially in combination with chemotherapy. The risk for secondary infections (mainly bacterial) is increased and cases of staphylococcal scalded skin syndrome, necrotising fasciitis and sepsis, in some cases with fatal outcome, have been reported (see Adverse Reactions).
Skin reactions are very common and treatment interruption or discontinuation may be required. According to clinical practice guidelines prophylactic use of oral tetracyclines (6 – 8 weeks) and topical application of 1% hydrocortisone cream with moisturiser should be considered. Medium to high-potency topical corticosteroids or oral tetracyclines have been used for the treatment of skin reactions.
If a patient experiences an intolerable severe skin reaction (≥ grade 3; Common Terminology Criteria for Adverse Events, CTCAE), cetuximab therapy must be interrupted. Treatment may only be resumed if the reaction has resolved to grade 2.
If the severe skin reaction occurred for the first time, treatment may be resumed without any change in dose level.
With the second and third occurrences of severe skin reactions, cetuximab therapy must again be interrupted. Treatment may only be resumed at a lower dose level (200 mg/m² after the second occurrence and 150 mg/m² after the third occurrence), if the reaction has resolved to grade 2.
If severe skin reactions occur a fourth time or do not resolve to grade 2 during interruption of treatment, permanent discontinuation of cetuximab treatment is required.
Electrolyte disturbances: Progressively decreasing serum magnesium levels occur frequently and may lead to severe hypomagnesaemia. Hypomagnesaemia is reversible following discontinuation of cetuximab. In addition, hypokalaemia may develop as a consequence of diarrhoea. Hypocalcaemia may also occur; in particular in combination with platinum-based chemotherapy the frequency of severe hypocalcaemia may be increased.
Determination of serum electrolyte levels is recommended prior to and periodically during cetuximab treatment. Electrolyte repletion is recommended, as appropriate.
Neutropenia and related infectious complications: Patients who receive cetuximab in combination with platinum-based chemotherapy are at an increased risk for the occurrence of severe neutropenia, which may lead to subsequent infectious complications such as febrile neutropenia, pneumonia or sepsis. Careful monitoring is recommended in such patients, in particular in those who experience skin lesions, mucositis or diarrhoea that may facilitate the occurrence of infections (see Adverse Reactions).
Cardiovascular disorders: An increased frequency of severe and sometimes fatal cardiovascular events and treatment emergent deaths has been observed in the treatment of non-small cell lung cancer, squamous cell carcinoma of the head and neck and colorectal carcinoma. In some studies association with age ≥ 65 years or performance status has been observed. When prescribing cetuximab, the cardiovascular and performance status of the patients and concomitant administration of cardiotoxic compounds such as fluoropyrimidines should be taken into account.
Eye disorders: Patients presenting with signs and symptoms suggestive of keratitis such as acute or worsening: eye inflammation, lacrimation, light sensitivity, blurred vision, eye pain and/or red eye should be referred promptly to an ophthalmology specialist.
If a diagnosis of ulcerative keratitis is confirmed, treatment with cetuximab should be interrupted or discontinued. If keratitis is diagnosed, the benefits and risks of continuing treatment should be carefully considered.
Cetuximab should be used with caution in patients with a history of keratitis, ulcerative keratitis or severe dry eye. Contact lens use is also a risk factor for keratitis and ulceration.
Colorectal cancer patients with RAS mutated tumours: Cetuximab should not be used in the treatment of colorectal cancer patients whose tumours have RAS mutations or for whom RAS tumour status is unknown. Results from clinical studies show a negative benefit-risk balance in tumours with RAS mutations. In particular, in these patients negative effects on progression-free survival (PFS) and overall survival (OS) were seen as add-on to FOLFOX4 (see Pharmacology: Pharmacodynamics under Actions).
Similar findings were also reported when cetuximab was given as add-on to XELOX in combination with bevacizumab (CAIRO2). However, in this study no positive effects on PFS or OS were demonstrated in patients with KRAS wild-type tumours, either.
Special populations: Only patients with adequate renal and hepatic function have been investigated to date (serum creatinine ≤ 1.5fold, transaminases ≤ 5fold and bilirubin ≤ 1.5fold the upper limit of normal).
Cetuximab has not been studied in patients presenting with one or more of the following laboratory parameters: haemoglobin < 9 g/dl, leukocyte count < 3000/mm3, absolute neutrophil count < 1500/mm3, platelet count < 100000/mm3.
There is limited experience in the use of cetuximab in combination with radiation therapy in colorectal cancer.
Effects on ability to drive and use machines: No studies on the effects on the ability to drive and use machines have been performed. If patients experience treatment-related symptoms affecting their ability to concentrate and react, it is recommended that they do not drive or use machines until the effect subsides. Use in Children: The efficacy of cetuximab in paediatric patients below the age of 18 years has not been established.