Cetuximab plus 5-FU/FA/oxaliplatin (FOLFOX-4) versus FOLFOX-4 in the first-line treatment of metastatic colorectal cancer (mCRC): OPUS, a randomized phase II study

Abstract

4035 Background: FOLFOX-4 is a standard first-line treatment for patients (pts) with mCRC. The IgG1 monoclonal antibody cetuximab has proven activity in combination with cytotoxic chemotherapy. Excellent response rates (RRs) have been reported with first-line cetuximab and FOLFOX-4. This randomized, controlled study was conducted to compare RRs of FOLFOX-4 + cetuximab vs FOLFOX-4. Methods: Pts with previously untreated epidermal growth factor receptor (EGFR)-expressing mCRC not resectable with curative intent were eligible. They were randomized 1:1, stratified by ECOG performance status (PS) (0–1 vs 2), to either Group A (cetuximab 400 mg/m2 initial dose then 250 mg/m2/week plus FOLFOX-4 every 2 weeks [oxaliplatin 85 mg/m2 day (d) 1; FA 200 mg/m2 d1, 2; 5-FU 400 mg/m2 bolus + 600 mg/m2 infusion over 22 h, d1, 2]) or Group B (FOLFOX-4 only). The primary objective was the best confirmed RR assessed by independent review; secondary objectives were progression- free survival (PFS), overall survival (OS), the R0 resection rate after metastatic surgery of curative intent and safety. Results: Between July 2005 and March 2006, 337 pts were randomized and treated in more than 70 centers in Europe. 181 (53.7%) pts were male; the median age of all pts was 61.0 years [24–82]; 305 (90.5%) pts had an ECOG PS of 0 or 1, and 32 (9.5%) of 2. The best overall confirmed RR was 45.6% in A and 35.7% in B. For pts with ECOG PS 0–1, RR was 49.0% in A and 36.8% in B (Odds Ratio 1.648, 95%CI [1.043- 2.604]). PFS and OS results are not yet available. The most common grade 3/4 adverse events were neutropenia (27.6% in A; 31.5% in B), diarrhea (7.1 and 6.0%), leucopenia (7.1 and 5.4%) and rash (9.4%, in A only). Conclusions: The addition of cetuximab increased the RR of FOLFOX-4 in first-line treatment of mCRC. Grade 3/4 adverse events, with the exception of skin rash, were not significantly more frequent in the cetuximab arm. No significant financial relationships to disclose.