Phase Ib study of cancer stem cell (CSC) pathway inhibitor BBI-608 administered in combination with FOLFIRI with and without bevacizumab (Bev) in patients (pts) with advanced colorectal cancer (CRC).

Cancers of the Colon, Rectum, and Anus
Session Type and Session Title: 
Poster Session C: Cancers of the Colon, Rectum, and Anus
Abstract Number: 


Poster Board Number: 
Poster Session C Board #D18
J Clin Oncol 34, 2016 (suppl 4S; abstr 569)
Joleen Marie Hubbard, Bert H. O'Neil, Derek J. Jonker, Thorvardur Ragnar Halfdanarson, Alexander Starodub, Axel Grothey, Laura Borodyansky, Chiang Li; Mayo Clinic, Rochester, MN; Indiana University Health University Hospital, Indianapolis, IN; Ottawa Hospital Cancer Centre, Ottawa, ON, Canada; Mayo Clinic, Scottsdale, AZ; Indiana University Health Goshen Center for Cancer Care, Goshen, IN; Boston Biomedical, Inc., Cambridge, MA

Abstract Disclosures


Background: BBI-608 is an oral first-in-class cancer stemness inhibitor that blocks STAT3-mediated transcription of cancer stemness genes. Potent anti-CSC activity was observed in vitro and in vivo,in mono and combination therapy. In phase I studies, BBI-608 was generally well tolerated with encouraging signs of anti-tumor activity. Methods: A phase Ib open label, multi-center study in pts with advanced CRC was undertaken to confirm the RP2D of BBI-608 in combination with FOLFIRI with or without BEV. BBI-608 was administered at 240 mg BID in combination with FOLFIRI (5-FU 400 mg/m2 bolus with 2400 mg/m2, irinotecan 180 mg/m2, and leucovorin 400 mg/m2infusion) with or without BEV 5 mg/kg, administered bi-weekly until progression of disease, unacceptable toxicity, or other discontinuation criterion was met. Results: 18 heavily pretreated pts with an average of > 3 prior lines of therapy of which 10 pts (56%) previously progressed on FOLFIRI were enrolled. Of the 17 pts evaluable for response, 8 pts received FOLFIRI and 9 pts received FOLFIRI with BEV in combination with BBI-608. Most common adverse events included grade 1 and 2 diarrhea, abdominal pain, nausea, vomiting and anorexia. No dose limiting toxicity or new adverse events were seen, and the safety profile was similar to that of each regimen as monotherapy. Grade 3 events related to protocol therapy included diarrhea occurring in 3 pts, fatigue in 2 pts and dehydration in 1 pt. All events resolved after dose reduction and/or start of anti-diarrheal medications. No significant pharmacokinetic interactions were observed. Disease control (PR+SD) was observed in 16 of 17 evaluable pts (94%) with 2 PR (per RECIST 1.1 criteria: 44% and 33% regression) and 14 SD (of which 13 (93%) had tumor regression < 25%). In the evaluable pts, median progression free survival was 5.54 months. Of 17 pts, 7 (41%) had prolonged SD of > 6 months. Conclusions: This phase Ib study confirmed that BBI-608 at 240 mg bid can be safely combined with FOLFIRI with and without BEV, and shows encouraging anti-tumor activity in heavily pretreated CRC pts, even in pts with prior progression on FOLFIRI-based therapy. Clinical trial information: NCT02024607