RAS testing of circulating cell-free DNA (cfDNA) from tissue RAS/BRAF wild-type metastatic colorectal carcinoma (mCRC) patients: Preliminary data from the Liquid Biopsy Monoclonal Antibodies in mCRC (LIBImAb) study.

• DOI: 10.1200/jco.2023.41.16_suppl.3046
• Publication Date: 2023-06-04T15:23:35Z
• Authors: Anna Maria Rachiglio; Alessandra Sacco; Matilde Lambiase; Salvatore Tufano; Angela Damato; Alessandra Raimondi; Luca Frassineti; Antonio Pazzola; Alfredo Colombo; Stefania Mosconi; Livio Blasi; Andrea Sartore-Bi...; Stefano Tamberi; Maura Rossi; Elena Romagnani; Francesca Filiali; Erika Gervasi; Ilenia La Grotteria; Nicola Normanno; Carmine Pinto
• Keywords: FOLFIRI; Liquid biopsy

3046 Background: In mCRC patients RAS/BRAF testing is usually performed on tissue biopsy in order to select for treatment with anti-EGFR monoclonal antibodies. Several studies described discordant RAS status between and cfDNA from the same patients. addition, up 30% of secondary resistance therapies become mutant at progression. The LIBImAb study a phase III, randomized, open-label, comparative, multi-centre trial assess superiority terms efficacy bevacizumab versus cetuximab combination FOLFIRI chemotherapy mCRC, wild-type tumor (RAS mut ) liquid biopsy. This supported by Italian Drug Agency (AIFA). We report preliminary data testing. Methods: Plasma samples enrolled are analyzed variants exons 2, 3 4 KRAS NRAS genes codon 600 BRAF mutations using fully automated Idylla system (Biocartis). Patients baseline randomized receive plus Cetuximab or Bevacizumab. baseline, treated 8 cycles and, if not progressed, they retested cfDNA. re-screening continue switch Results: 169 75 have been tested as January 31, 2023. Analysis plasma detected 16 16/169 (9.5%). particular, 12 (7.1%, exon 2 3) (2.3%, all 2) were found. test also V600 (1.8%) additional overall concordance was 88.8%. 6/75 (8%) obtained FOLFIRI/cetuximab treatment. revealed presence 5 (6.7%, 1 mutation (1.3%, 2). A variant patient (1.3%). rate cases 9.3%. Conclusions: These suggest that might better recapitulate heterogeneity be useful clinical practice complement relevance will determined trial.