This unique trial will yield prospective information on the efficacy of cetuximab and whether this is further enhanced with chemotherapy in two distinct populations of patients with metastatic colorectal cancer: the "quadruple wild type", which may 'superselect' for tumours sensitive to EGFR-inhibition, and the rare KRAS G13D mutated tumours, which are also postulated to be sensitive to the drug.
Participating laboratories contributed information on KRAS mutation frequencies, including the G13D mutation type, as well as turnaround times for tumor block retrieval and testing.
Mutations in primary tumors were identified in three regions; KARS (G13D) and APC (R876*) in P1-2, TP53 (A161S) in P1-3, and KRAS (G12D), PIK3CA (Q546R), and ERBB4 (T272A) in P1-4.
KRAS exon 2 mutation variants were associated with heterogeneous outcome compared with unmutated tumors with KRAS G12C and G13D (trend) being associated with rather poor survival.