Introduction
SOLID TUMORS
PCNA plays an essential role in orchestrating normal DNA replication, but also acts as a platform for recruiting components of the DNA repair and damage bypass and/or tolerance during replicative stress [The multi-functionality of PCNA-governed regulation under normal and stressed conditions is based on its ability to bind proteins involved in multiple cellular processes. These interactions are mainly mediated via two conserved PCNA-interacting sequences (motifs) found in more than 500 proteins: the PIP-box (PCNA-interacting peptide-box) [ATX-101 is a novel cell-penetrating APIM-containing peptide, shown to target PCNA and block PCNA-protein interactions [To our knowledge, ATX-101 is the only compound that selectively targets PCNA regulatory roles during cellular stress, and a first-in-class compound in clinical development.Here we report results of the ATX-101 first-in-human study in patients with advanced solid tumors. This open-label, single arm Phase 1 study, consisting of two sub-studies, investigated 4 doses of ATX-101 (20, 30, 45, and 60 mg/m