Matsuda C, et al. - In this single-arm phase II clinical trial, researchers investigated if the alternate-day administration of S-1 plus irinotecan vs consecutive-day S-1 administration (standard IRIS regimen) as second-line treatment would reduce the incidence of severe diarrhea in patients with metastatic colorectal cancer failed to treat with first-line treatment of oxaliplatin and fluoropyrimidine. 21% was hypothesized to be threshold incidence and 10% as an expected incidence from previous studies with one-sided alpha 0.05. No significant effectiveness of alternate-day S-1 administration was noted in reducing diarrhea in patients who received second-line treatment for metastatic colorectal cancer. The median progression-free survival and overall survival of 8.4 months and 17.1 months were reported.