Background: The primary analysis of ASPECCT demonstrated that pmab was non-inferior to cmab for overall survival (OS) in chemorefractory WT KRASmCRC. Here, we report the final analysis of ASPECCT. Methods: In ASPECCT, patients (pts) had WT KRASmCRC, ECOG performance status (PS) ≤2, prior irinotecan, oxaliplatin, and fluorouracil treatment, and no prior anti-EGFR therapy. Pts were stratified by geographic region (North America/Western Europe/Australia vs rest of world) and ECOG PS (0-1 vs 2) and randomized 1:1 to receive pmab 6 mg/kg q2w or cmab 400 mg/m2 followed by 250 mg/m2 qw. The primary endpoint was OS assessed for non-inferiority (retention of ≥50% of the cmab effect vs best supportive care [BSC]; HR=0.55 [95% CI: 0.41 - 0.74] based on NCIC CTG C0.17). Secondary endpoints included progression-free survival (PFS), objective response rate (ORR), and safety. All pts were followed for survival for up to 2 years after the last pt was randomized and a final analysis of efficacy and safety was conducted. No formal hypothesis testing was performed. Results: 999 pts were randomized and treated: 499 pmab and 500 cmab. 90% of pts had died at the time of this analysis (78% in the previously reported primary analysis). Baseline demographics and disease characteristics were similar between arms. Non-inferiority results for OS are shown (Table). Overall, any grade and grade 3-4 adverse events (AEs) were similar between arms. AEs of interest were (pmab vs cmab): grade 3-4 skin toxicity 13% vs 10%, grade 3-4 infusion reactions 0.5% vs 2%, and grade 3-4 hypomagnesemia 7% vs 3%. Conclusions: Consistent with the primary analysis, the final analysis of ASPECCT showed that pmab was non-inferior to cmab for OS in chemorefractory WT KRASmCRC. Safety profiles were as expected for pmab and cmab. Clinical trial information: NCT01001377

*Rate of cmab OS benefit (cmab:BSC) retained by pmab.