Final Results From Aspecct: Randomized Phase 3 Non-Inferiority Study Of Panitumumab (Pmab) Vs Cetuximab (Cmab) In Chemorefractory Wild-Type (Wt) Kras Exon 2 Metastatic Colorectal Cancer (Mcrc)

3586 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 conduct...