...40 patients were enrolled, 38 treated. Median age was 56 years (range 22-76), 42% were female, 70% ECOG 1, median body mass index was 27.10 (range 17.10-40.40), 60% harbored KRAS mutated mCRC...The combination of metformin and irinotecan in this heavily pre-treated mCRC population seems safe and promising enough to merit further evaluation in randomized trials.