CanStem303C trial: A phase III study of napabucasin (BBI-608) in combination with 5-fluorouracil (5-FU), leucovorin, irinotecan (FOLFIRI) in adult patients with previously treated metastatic colorectal cancer (mCRC).

TPS3619Background: Cancer stem cells are considered to be fundamentally important for resistance to therapy, recurrence and metastasis. Napabucasin is a first-in-class cancer stemness inhibitor in development identified by its ability to inhibit STAT3-driven gene transcription and spherogenesis of cancer stem cells (Li et al, PNAS 112(6):1839, 2015). Preclinically, napabucasin sensitizes cancer cells to chemotherapeutics, including 5-FU and irinotecan. Encouraging anticancer activity in advanced CRC was observed in a phase Ib/II (Bendell et al, GI ASCO 2017) study of 63 pts with disease control rate (DCR) of 93% (28/30) and overall response rate (ORR) of 33% (10/30) in FOLFIRI-naive pts who have had an on-study RECIST evaluation. On the basis of these data, a phase III trial is being conducted in North America, Europe, Australia, and Asia. Methods: This study (ClinicalTrials.gov NCT02753127) will assess the efficacy of napabucasin+FOLFIRI vs FOLFIRI in pts with mCRC (n = 1250). Addition of bevacizumab (be...