Key clinical point: Acquired genomic alterations (Acq-Gas) associated with epidermal growth factor receptor (EGFR)-resistance in later lines were rare with first-line anti-EGFR-antibody combined with highly active chemotherapy and comparable with non-anti-EGFR regimen.
Major finding: On progression, ≥1 Acq-GA of interest developed in 6.6% of patients on anti-EGFR-chemotherapy compared with 10.1% of patients on anti- vascular endothelial growth factor (VEGF)-chemotherapy (odds ratio [OR] 0.62; 95% CI 0.20-2.11) and 62.0% of patients on anti-EGFR-antibody therapy in later lines (OR 0.09; 95% CI 0.03-0.23).
Study details : This was a post hoc analysis of the CALGB/SWOG-80405 trial including patients with mCRC who progressed on first-line cetuximab (anti-EGFR)-chemotherapy or bevacizumab (anti-VEGF)-chemotherapy and had pretreatment and post-progression plasma samples available for circulating tumor DNA testing.
Disclosures: This study was supported by the National Cancer Institute of the US National Institutes of Health . Some authors declared receiving honoraria or research funding from, having consulting or advisory roles or stock or other ownership interests in, or serving on speakers’ bureau for various sources.
Source: Raghav K et al. Acquired genomic alterations on first-line chemotherapy with cetuximab in advanced colorectal cancer: Circulating tumor DNA analysis of the CALGB/SWOG-80405 trial (Alliance). J Clin Oncol. 2022 (Sep 6). Doi: 10.1200/JCO.22.00365