Subgroup analyses results of the PETACC8 phase III trial comparing adjuvant FOLFOX4 with or without cetuximab (CTX) in resected stage III colon cancer (CC).

3525^ Background: Potential benefit of adding CTX to the current standard treatment for stage III CC, was assessed. Subgroup analyses of demographic, clinical and molecular data may improve our understanding of this patient population. Methods: Patients (pts) were randomized 28-56 days following resection. They received 12 biweekly cycles of oxaliplatin 85 mg/m2 day (d) 1, with leucovorin 200 mg/m2, 5-FU 400 mg/m2 bolus IV, followed by 5-FU 600 mg/m2 22-hr IV on d1-2 (FOLFOX4), without (arm A) or with weekly CTX (arm B) 250 mg/m2 (initial dose 400 mg/m2). Primary endpoint was disease free survival time (DFS). Secondary endpoints included overall survival (OS), treatment compliance and safety. Enrolment was restricted to KRAS wt pts in 06/2008. Planned accrual of 1,407 KRAS wild-type (wt) pts provided 90% power to detect a hazard ratio (HR) of 0.75 with 2-sided α=0.05, with interim analyses after 65% of planned events. Preplanned subgroup analyses were performed. Results: 1,602 KRAS wt pts (811 arm A, 791 ...