The primary objective is to evaluate progression free survival (PFS) in patients with RAS wild type metastatic CRC treated in the first-line with VPA plus panitumumab or cetuximab maintenance, or panitumumab or cetuximab maintenance alone.~The secondary objectives are (i) to evaluate overall survival (OS) and objective response rates (ORRs; RECIST v 1.1) in patients with RAS wild type metastatic CRC treated in the first-line with VPA plus panitumumab or cetuximab maintenance, and panitumumab or cetuximab maintenance alone; and (ii) to evaluate the safety (NCI CTCAE v5.0) of first-line maintenance treatment with VPA plus panitumumab or cetuximab, and panitumumab or cetuximab maintenance alone in patients with RAS wild type metastatic CRC.~The tertiary and exploratory objectives are:~To evaluate Health-Related Quality of Life (EORTC QLQ-C30 and EQ-5D-5L) in patients with RAS wild type metastatic CRC treated in the first-line with VPA plus panitumumab or cetuximab maintenance, and panitumumab or cetuximab maintenance alone.~Exploratory analyses including, but not limited to:~(i) Determining whether changes in levels of histone acetylation in peripheral blood mononuclear cells (PBMCs) are associated with improved efficacy with VPA plus anti-EGFR monoclonal antibody maintenance treatment; and (ii) determining whether potential resistance-conferring mutations in circulating tumour DNA (ctDNA) are associated with efficacy outcomes in patients treated with anti-EGFR monoclonal antibody maintenance.
The aim of this study is to determine the efficacy of combining the histone deacetylase (HDAC) inhibitor sodium valproate (VPA) with anti-EGFR monoclonal antibody (panitumumab or cetuximab) maintenance in the first-line treatment of patients with RAS wild type metastatic CRC.