Cetuximab administered once every second week to patients with metastatic colorectal cancer: a two-part pharmacokinetic/pharmacodynamic phase I dose-escalation study.

BACKGROUND: This phase I dose-escalation study was designed to determine the maximum tolerated dose (MTD) and recommended dose of cetuximab administered on an every-second-week schedule to patients with metastatic colorectal cancer, on the basis of safety, pharmacokinetic and pharmacodynamic evaluation. PATIENTS AND METHODS: The study comprised two parts: a 6-week cetuximab monotherapy dose-escalation phase and a subsequent combination therapy phase, during which patients received cetuximab, at the same dose/schedule as in the monotherapy phase, followed by irinotecan plus infusional 5-fluorouracil/folinic acid (FOLFIRI). Patients in the control group received cetuximab as a 400 mg/m(2) initial dose, then 250 mg/m(2)/week and in the dose-escalation group, at 400-700 mg/m(2), every second week. RESULTS: Sixty-two patients were included in the study. The MTD of cetuximab administered on an every-second-week schedule was not reached. The safety profiles were similar across all groups. Response rates in the cetuximab monotherapy and combination therapy phases were 15% and 42%, respectively. Trough levels for the 500, 600 mg/m(2) and standard weekly regimens were comparable. CONCLUSION: Cetuximab can be safely administered once every second week at doses between 400 and 700 mg/m(2), with 500 mg/m(2) being the most convenient and feasible dose for future studies.

Phase I/II study of gefitinib and capecitabine in patients with colorectal cancer.

OBJECTIVE: The objectives of this phase I/II study were to determine the maximum tolerated dose (MTD), characterise the principal toxicities in the phase I part and assess the efficacy in the phase II part of gefitinib, an oral selective inhibitor of the epidermal growth factor receptor, in combination with capecitabine in patients with advanced colorectal cancer (CRC). METHODS AND PATIENTS: Patients with advanced CRC were treated with gefitinib administered daily for 21 days and capecitabine administered twice daily for 14 days of a 21-day cycle. The dose levels of gefitinib (mg) and capecitabine (mg/m(2) bid) assessed were 250/1000 and 250/ 1250. An expanded cohort was enrolled at the MTD to better characterise toxicity and efficacy. A total of 32 previously treated patients were accrued. In the phase I part 10 subjects were treated, with one dose-limiting toxicity. Overall 26 patients were treated at the MTD of the combination, which was gefitinib 250 mg/day and capecitabine 1250 mg/m(2) twice daily. RESULTS: The most frequent treatment-related adverse events included asthenia, diarrhoea, nausea, rash and anorexia. The incidence profile was very similar in phases I and II. No objective responses were documented but 53% of the patients achieved stable disease as best response to therapy. CONCLUSIONS: Capecitabine 1250 mg/m(2) twice daily 14 of 21 days and gefitinib at 250 mg/day can be safely administered in combination. The combination is relatively well tolerated. There were no objective responses, although an interesting stabilisation rate was documented, in previously treated advanced CRC patients.