OBJECTIVES: Identify the extent of fortnightly (W2) vs. weekly cetuximab (W1) regimens in use, collate patient and clinician (nurse) views and preferences for different cetuximab regimens, model the cost of healthcare provision with each regimen. METHODS: A mixed-methods approach comprising of a review of regional payment claims relating to cetuximab treatment regimens incorporating modelling using standard payment terms and actual drug costs, and one-to-one interviews conducted with a range of purposively selected participants at one urban hospital. RESULTS: Half of identifiable cetuximab regimens (n=32) were W1 (mean dose interval 7.8 days) and 50% were W2 regimens (mean dose interval 14.4 days). Modelling of the W2 regimen demonstrated 48% fewer admissions and associated costs; these were not directly correlated to cetuximab frequency due to co-administered drugs. Each admission avoided was estimated to save payors £400 including supportive drugs and funding of pharmacy services. No reduction in cetuximab expenditure was expected or observed. The W2 regimen was estimated to yield net annualised reduction in expenditure in the locality (pop 3.2m) at March 2015 values of £129,000 with a further £147,000 maximum opportunity. Patients were generally unaware of different treatment regimens and accepted that which had been prescribed. Patients felt that a fortnightly regimen would be more convenient and acceptable providing there was no impact on efficacy or safety. Clinicians felt the W1 regimen was better tolerated than the W2 regimen. Nurses also recognised that fewer admissions were required with the W2 regimen but each was of longer duration. CONCLUSIONS: The use of the W2 regimen in preference to W1 has provided substantial savings to payors although less than half of the opportunity had been realised. Clinicians favoured the W1 regimen primarily due to incidence of drug toxicities. Patients were poorly informed and consulted concerning the choice of cetuximab regimen.