A phase I first-in-human study of PRI-724 in patients (pts) with advanced solid tumors.

2501 Background: PRI-724 is a first-in-class modulator of Wnt signaling that inhibits the CREB binding protein and β-catenin interaction. In pre-clinical models, PRI-724 (active metabolite C82) increases p300/β-catenin binding and promotes stem cell differentiation thereby eliminating tumor initiating cells and increasing sensitivity to cytotoxic or targeted drugs. Methods: PRI-724 was given as a continuous infusion X 7 days q 2 wks. There was an initial accelerated dose escalation with one pt per dose level and a plan to revert to a 3+3 escalation after 640 mg/m2 unless a dose limiting toxicity (DLT) or 2 moderate toxicities occurred earlier. Eligibility criteria: adequate bone marrow function, AST/ALT <5XULN, total bilirubin<1.5 mg/dL. Survivin/BIRC5 expression was measured by immunomagnetic RT-PCR on circulating tumor cells (CTC). Results: 18 pts treated; median age: 53 years (38-71); 12 (67%) males; median number of prior therapies: 3 (1-5). There was one DLT of grade 3 hyperbilirubinemia. Grade 3 AEs...