2542 Background: Cancer Stem Cells (CSC) are considered to be fundamentally responsible for malignant growth, relapse, metastasis, and resistance to conventional therapies. BBI608 is an orally-administered first-in-class cancer stemness inhibitor which blocks CSC self-renewal and induces cell death in CSC as well as non-stem cancer cells by inhibition of the Stat3, Nanog and b-catenin pathways, and has shown potent anti-tumor and anti-metastatic activities pre-clinically. Methods: A phase 1 dose escalation studyin adult patients with advanced cancer who had failed standard therapies was conducted to determine the safety, tolerability, recommended phase 2 dose (RP2D), pharmacokinetics and preliminary anti-tumor activity of BBI608. A modified Simon accelerated titration scheme was used for dose escalation, with a cycle consisting of twice-daily oral administration of BBI608 for 4 weeks. Cycles were repeated every 4 weeks (28 days) until progression of disease, unacceptable toxicity, or other discontinuation...