Aim: To investigate efficacy and safety of cetuximab combined with two chemotherapy regimens in patients with unresectable metastatic colorectal cancer (mCRC).
Methods: Randomized patients received cetuximab with 5-fluorouracil (5-FU), folinic acid (FA) and oxaliplatin (FOLFOX) 6 (arm A, n = 74) or 5-FU, FA and irinotecan (FOLFIRI) (arm B, n = 77). KRAS mutation status was determined retrospectively in a subset of tumors (n = 117).
Results: No significant difference was found between treatment arms A and B in the progression-free survival (PFS) rate at 9 mo, 45% vs 34%; median PFS, 8.6 mo vs 8.3 mo [hazard ratio (HR) = 1.06]; overall response rate (ORR) 43% vs 45% [odds ratio (OR) = 0.93] and median overall survival (OS), 17.4 mo vs 18.9 mo (HR = 0.98). Patients with KRAS wild-type tumors demonstrated improved PFS (HR = 0.55, P = 0.0051), OS, (HR = 0.62, P = 0.0296) and ORR (53% vs 36%) and in arm A, improved PFS (HR = 0.49, P = 0.0196), OS (HR = 0.48, P = 0.0201) and ORR (56% vs 30%), compared with patients with KRAS mutated tumors. In arm B no significant differences were found in efficacy by KRAS mutation status. Treatment in arms A and B was generally well tolerated.
Conclusion: This study confirms that combinations of cetuximab with FOLFOX6 or FOLFIRI are effective and significantly improve clinical outcome in KRAS wild-type compared with KRAS mutated mCRC.