Phase I/II study of preoperative cetuximab, capecitabine, and external beam radiotherapy in patients with rectal cancer

Background: To assess the safety and preliminary efficacy of concurrent radiotherapy, capecitabine, and cetuximab in the preoperative treatment of patients with rectal cancer. Patients and methods: Forty patients with rectal cancer (T3-T4, and/or N+, endorectal ultrasound) received preoperative radiotherapy (1.8 Gy, 5 days/week for 5 weeks, total dose 45 Gy, three-dimensional conformal technique) in combination with cetuximab [initial dose 400 mg/m(2) intravenous given 1 week before the beginning of radiation followed by 250 mg/m(2)/week for 5 weeks] and capecitabine for the duration of radiotherapy (650 mg/m(2) orally twice daily, first dose level; 825 mg/m(2) twice daily, second dose level). Results: Four and six patients were treated at the first and second dose level of capecitabine, respectively. No dose-limiting toxicity occurred. Thirty additional patients were treated with capecitabine at 825 mg/m(2) twice daily. The most frequent grade 1/2 side-effects were acneiform rash (87%), diarrhea (65%), and fatigue (57%). Grade 3 diarrhea was found in 15%. Three grade 4 toxic effects were recorded: one myocardial infarction, one pulmonary embolism, and one pulmonary infection with sepsis. Two patients (5%) had a pathological complete response. Conclusions: Preoperative radiotherapy in combination with capecitabine and cetuximab is feasible with some patients achieving pathological downstaging.