Phase I Trial of XL309, a USP1 (BRCA/HRD directed) Inhibitor in Advanced Tumors

This open-label, multicenter Phase I study led by Exelixis evaluates XL309 as a single agent and with olaparib in patients with advanced solid tumors, including HRR-mutant, CRPC, breast, pancreatic, and HGSOC cancers. It is the first-in-human trial assessing a USP1 inhibitor with dose-escalation and expansion cohorts to determine safety, tolerability, and preliminary antitumor activity.