Biweekly cetuximab in combination with FOLFOX-4 in the first-line treatment of wild-type KRAS metastatic colorectal cancer: final results of a phase II, open-label, clinical trial (OPTIMIX-ACROSS Study)

Abstract

Background: This phase II study aims to evaluate the efficacy and safety of biweekly cetuximab in combination with oxaliplatin, leucovorin, and fluorouracil (FOLFOX-4) as first-line treatment of metastatic wild-type KRAS colorectal cancer. Methods: Previously untreated patients with wild-type KRAS tumours received biweekly cetuximab (500 mg/m2 on day 1) plus FOLFOX-4 (oxaliplatin 85 mg/m2 on day 1, leucovorin 200 mg/m2 on days 1 and 2, and fluorouracil as a 400 mg/m2 bolus followed by a 22-hour 600 mg/m2 infusion on day 1 and 2). Treatment was continued until disease progression, onset of unacceptable toxicities, metastases surgery, or discontinuation request. The primary endpoint was ORR. Results: The intention-to-treat population included 99 patients with a median age of 64.1 years (range, 34-82). The ORR was 60.6% (95% CI, 50.3% to 70.3%). The median follow-up was 17.8 months; the median OS and PFS were 20.8 and 10.1 months, respectively. Metastases from colorectal cancer were surgically resected in 26 (26.3%) patients, with complete resection achieved in 18 (69.2%) patients. Median PFS and OS in patients undergoing metastatic resection were 12.6 and 29.5 months, respectively. The most common grade 3-4 toxicities were neutropenia (32.3%), acne-like rash (15.2%) and diarrhoea (11.1%). Conclusions: The efficacy of the biweekly combination of cetuximab with FOLFOX-4 in patients with wild-type KRAS tumours supports the administration of cetuximab in a dosing regimen more convenient for patients and healthcare providers. The activity of the biweekly administration is similar to what has been reported for the weekly regimen. Reported toxicity was also consistent with the known toxicity profile of weekly cetuximab. Trial registration: EudraCT Number 200800690916