The results of this placebo-controlled, doubleblind, phase 3 clinical trial conducted in Japan and in the United States, Europe, and Australia confirmed the results of previous assessments of oral TAS-102 in patients with metastatic colorectal cancer who had already undergone extensive treatment: TAS-102 was associated with a clinically relevant prolongation of overall survival in essentially all treatment subgroups. The superiority of TAS-102 over placebo was also evident in analyses of the control of clinical disease and the time to disease progression as determined by radiographic assessment (i.e., progressionfree survival) and in the assessment of symptoms
(i.e., deterioration of performance status).This superiority is particularly meaningful given that more than 90% of the study patients had disease that had been refractory to treatment with fluoropyrimidines when they were last exposed
to such drugs and that more than 50% had disease that was refractory to treatment in which a fluoropyrimidine was a component of their most recent treatment regimen; these observations provide clinical support for prior preclinical data5 that indicated that the mechanism of action of TAS-102 differs from that of fluoropyrimidines. In addition, the clinical benefit associated with TAS-102 was maintained irrespective of prior treatment with regorafenib.