196 Background: Cancer stemness is thought to be associated with resistance to chemotherapies. BBI608, a first-in-class cancer stemness inhibitor that works through inhibiting the Stat3 pathway, has shown potent synergistic anti-tumor activity with paclitaxel in vivo. In a phase Ib dose escalation study in patients with advanced solid tumors, BBI608 plus weekly paclitaxel was well tolerated and a RP2D of BBI608 480 mg BID was determined. Methods: Patients with heavily pretreated metastatic pancreatic adenocarcinoma were enrolled in a phase Ib/II extension study to assess safety, tolerability, and preliminary anti-cancer activity in patients with this diagnosis. BBI608 was administered orally at a starting dose of 480 mg or 500 mg twice daily along with paclitaxel 80 mg/m2 IV weekly 3 of every 4 weeks. A sample size of 40 set the bounds of the 90% CI at ±10% to 14%, assuming a DCR of 60% to 80%. Safety and efficacy results for the cohort will be presented as late breaking data. Results: 41 patients were en...