The FDA approved TAS-102 (Lonsurf; Taiho Oncology, Inc.) for the treatment of 
patients with metastatic colorectal cancer (mCRC) who have been previously 
treated with fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy; 
an anti-VEGF biological therapy; and if RAS wild type, an anti-EGFR therapy. In 
an international, multicenter, double-blinded, placebo-controlled trial 
(TPU-TAS-102-301, herein referred to as RECOURSE), 800 patients with previously 
treated mCRC were randomly allocated (2:1) to receive either TAS-102 35 mg/m2 
orally twice daily after meals on days 1 through 5 and 8 through 12 of each 
28-day cycle (n = 534) or matching placebo (n = 266). The trial demonstrated a 
statistically significant improvement in overall survival for those randomized 
to receive TAS-102, with a median survival of 7.1 months in the TAS-102 arm 
[confidence interval (CI), 6.5-7.8] and 5.3 months in the placebo arm [CI, 
4.6-6.0; hazard ratio (HR), 0.68; 95% CI, 0.58-0.81; P < 0.001, stratified 
log-rank test]. The trial also demonstrated a statistically significant 
prolongation of progression-free survival (HR, 0.47; 95% CI, 0.40-0.55; P < 
0.001). The most common adverse reactions, in order of decreasing frequency, 
observed in the patients who received TAS-102 were anemia, neutropenia, 
asthenia/fatigue, nausea, thrombocytopenia, decreased appetite, diarrhea, 
vomiting, abdominal pain, and pyrexia. Adverse events led to discontinuation of 
TAS-102 in 3.6% of patients, and 13.7% required a dose reduction. The most 
common adverse reactions leading to dose reduction were neutropenia, anemia, 
febrile neutropenia, fatigue, and diarrhea. Clin Cancer Res; 23(12); 2924-7. 
©2017 AACR.