The impact of cetuximab on the capecitabine plus oxaliplatin (XELOX) combination in first-line treatment of metastatic colorectal cancer (MCC): A randomized phase II trial of the Swiss Group for Clinical Cancer Research (SAKK)

Abstract

3551 Background: XELOX is a valuable alternative to continuous infusion FOLFOX type regimens in the treatment of MCC (Borner et al, JCO 2002, 1759). Cetuximab is an EGFR antibody, which has been shown to improve the efficacy of chemotherapy. A phase II study in first-line treatment of MCC has demonstrated a high response rate combining cetuximab with FOLFOX (Tabernero et al, Proc ASCO 2004, 3512). Methods: Multicenter, randomized two-arm phase II trial: OXA 130 mg/m2 day 1 and oral CAP 1000 mg/m2 bid days 1–14 every 21 days alone or in combination with cetuximab 250 mg/m2 weekly after a loading dose of 400 mg/m2. Treatment was limited to a maximum of 6 cycles. With 37 patients in each arm, the power was 90% to select the truly better arm if the true between-arm difference in response rate (RECIST) is at least 15%. The study was open for accrual until October 2005. Results: We present here the results of 74 patients included in the study. In 67 patients the first response data are available (investigators’ assessment after 3 cycles). The two arms are well balanced for relevant patient, disease and treatment characteristics. The study treatment was well tolerated with grade 3/4 toxicities in < 10% of the cycles in each arm. The frequency of side effects was balanced, but with more frequent skin toxicity in the cetuximab arm (6% versus 0% grade 3/4). Conclusions: Cetuximab seems to positively interact with XELOX in terms of efficacy but not toxicity. The cetuximab/XELOX combination appears to be a valuable option in first-line treatment of MCC especially if high response rates are a primary objective. This trial was supported in part by Merck KGaA and Sanofi-Aventis Switzerland. [Table: see text] No significant financial relationships to disclose.