DGI-071 The Rational Use of Cetuximab in Metastatic Colorectal Cancer

Background Cetuximab label indication includes treatment of epidermal growth factor receptor (EGFR)-expressing, KRAS wild-type metastatic colorectal cancer in several possible ways: combination with irinotecan-based chemotherapy, first-line in combination with FOLFOX and as a single agent after oxaliplatin- and irinotecan-based treatment failure in irinotecan-intolerant patients. In our hospital, a multidisciplinary team drawn from the Oncology and Pharmacy services has established a consensus for the rational use of cetuximab as first or second-line agent in association with other chemotherapeutic agents and as monotherapy in third-line treatment after the failure of oxaliplatin and irinotecan-based treatment. Purpose To verify the relevance of cetuximab prescription to the local protocol and cheque the label indications for cetuximab in our hospital. Materials and Methods A retrospective study of patients diagnosed with metastatic colorectal cancer between 2006–2012 with available KRAS status. Patients were followed up for a minimum of three months after diagnosis. Results Twenty-six patients were collected (mean age: 62.2 ± 12.6 years; 53.8% male). KRAS mutation was negative in 42.3% (11/26) patients and therefore they were eligible for treatment with cetuximab. Five out of those 11 patients underwent cetuximab treatment (5/11; 45.5%): three associated with oxaliplatin in first-line treatment, one associated with irinotecan in second-line treatment and one as monotherapy in second-line treatment. Four out of these 5 prescriptions of cetuximab were in accordance to our local protocol and label (4/5; 80.0%). One prescription was not in accordance with either the local protocol or the cetuximab label; due to this the patient was treated with oral capecitabine as first-line and cetuximab monotherapy as second-line treatment. Three KRAS-negative patients (3/11; 27.3%) are currently in treatment with irinotecan as second-line therapy. Three KRAS-negative patients were lost to follow-up after undergoing second-line treatment not known to contain a cetuximab prescription (3/11; 27.3%). Fifteen patients positive for KRAS mutation (15/26; 57.7%) were not treated with cetuximab. Conclusions Ninety-five percent of cetuximab prescriptions in our hospital are in accordance with the established local protocol and the cetuximab label (19/20). No conflict of interest.