ESMO Congress 2026

Cetuximab's evidence base in metastatic colorectal cancer was established by several randomized trials: in irinotecan-refractory disease, cetuximab plus irinotecan achieved a significantly higher response rate than cetuximab alone (22.9% vs 10.8%) ^[3]; in the first-line setting, adding cetuximab to FOLFIRI improved progression-free survival (hazard ratio 0.85) ^[5]. Yet KRAS status drew a clear boundary of benefit — a randomized trial showed a significant interaction between treatment and KRAS mutation status ^[5], and tumors harboring mutated K-ras did not benefit from cetuximab ^[6]. KRAS-mutant colorectal cancer is thus precisely the population in which the EGFR antibody has long offered no benefit, and this forms the immediate backdrop of the current report.

What was presented at ESMO26 are preliminary clinical results of QTX3034, an oral G12D-preferring KRAS inhibitor, combined with cetuximab ± mFOLFOX6 in KRAS G12D-mutant metastatic colorectal cancer. Two posts gave the headline numbers as ORR 25% vs 50% and DCR 75% vs 90%, which the posters interpreted as an encouraging signal for adding chemotherapy; another post reported ORR 26% and DCR 79% (n=19), noting 2/4 responses after adding FOLFOX. On safety there were no new safety signals, which the poster said supports the combination with cetuximab. The numbers differ across posts, and the official figures remain to be confirmed.

Relative to existing knowledge, this readout advances two points. First, in a population defined by KRAS mutation that was previously shown not to benefit from cetuximab ^[6], responses emerged after directly inhibiting KRAS G12D while simultaneously blocking EGFR — effectively re-testing the value of the EGFR antibody in this population. Second, the ± mFOLFOX6 design follows the same logic as the historical finding in colorectal cancer that cetuximab plus chemotherapy outperformed monotherapy ^[3], and the on-site discussion indeed centered on how large chemotherapy's incremental benefit is, and whether dual KRAS/EGFR blockade can deliver durable control without chemotherapy.

The limitations are equally clear: the cohorts are small (n=19 in one post; only 2/4 responses in the FOLFOX group), multiple posters emphasized the need for durability and comparative data; and these are only preliminary results, with inconsistent numbers across posts and official data to be confirmed.