In combination with platinum-based chemotherapy, the frequency of severe leukopenia or severe neutropenia may be increased, and thus may lead to a higher rate of infectious complications such as febrile neutropenia, pneumonia and sepsis compared to platinum-based chemotherapy alone (see Precautions).
In combination with fluoropyrimidines, the frequency of cardiac ischaemia including myocardial infarction and congestive heart failure as well as the frequency of hand-foot syndrome (palmar- plantar erythrodysaesthesia) were increased compared to that with fluoropyrimidines.
In combination with capecitabine and oxaliplatin (XELOX) the frequency of severe diarrhoea may be increased.
A formal interaction study showed that the pharmacokinetic characteristics of cetuximab remain unaltered after co-administration of a single dose of irinotecan (350 mg/m2 body surface area). Similarly, the pharmacokinetics of irinotecan were unchanged when cetuximab was co-administered.
No other formal interaction studies with cetuximab have been performed in humans.