A phase III trial showed that drug treatment with a new nucleoside analogue was clinically meaningful in terms of prolonged survival and improved physical status scores in patients. The trial included 800 patients with metastatic colorectal cancer who had failed at least two prior chemotherapy regimens. In addition to this, there was a statistically significant 32% reduction in mortality at a median follow-up of 8 months. TAS-102 treatment was well tolerated, and its use prolonged the time to deterioration in physical status scores by more than 40% compared to patients randomly assigned to the placebo group, Professor Erik Van Cutsem said at the annual meeting of the European Society of Clinical Oncology. The ability of TAS-102 to stabilize patients’ physical status and its benefit on the main evaluation item, overall survival, is an important clinical parameter. It shows a positive effect of the drug on quality of life, said Prof. Cutsem (Head of the Department of Clinical Gastroenterology Oncology, Leuven Hospital, Belgium). TAS-102 contains trifluridine, a nucleoside analogue incorporated into the DNA of tumor cells, which causes dysfunction of tumor cells while inhibiting their growth. tipiracil hydrochloride, another drug in TAS-120, inhibits the breakdown of trifluridine. The RECOURSE trial (studying the efficacy of TAS-102 in patients with standard chemotherapy-refractory metastatic colorectal cancer) randomized 800 patients with metastatic colorectal cancer who had failed at least 2 previous regimens from 114 clinical centers in 13 countries between June 2012 and October 2013. More than half of the patients had failed treatment or were intolerant to at least 4 previous regimens. More than 3/4 of the patients were diagnosed with metastatic colorectal cancer before 18 months of enrollment. The median age of the patients was 63 years. At enrollment, they had an Eastern Oncology Collaborative Group physical status score of 0 or 1. Patients received TAS-102 35 mg/m2 orally twice daily on days 1-5 and 8-12 of each course of treatment, every 4 weeks. The risk ratio for the application of this effective drug treatment was 0.68 (confidence interval, 0.58-0.81; P<0.0001), reported by Professor Van Cutsem. At one year, 27% of the 534 patients treated with TAS-102 were alive, compared with 18% of the 266 patients randomly assigned to the placebo group. A pre-set subgroup analysis showed that patients in all subgroups would benefit. A multivariate analysis showed a similar effect on overall survival. A secondary analysis showed that tas-102 treatment significantly prolonged progression-free survival (HR, 0.48; CI, 0.41-0.57; P<0.0001). The median time to worsening of the physical status score (for a score of 2) was 5.7 months in patients treated with tas-102, whereas the median time to worsening of the physical status score (for a score of 2) was 4.0 months in patients treated with placebo. < span=""> The incidence of non-hematologic grade 3 or 4 adverse reactions due to TAS-102 was low. The most common adverse reactions are generally grade 1 or 2 and include nausea, diarrhea, and vomiting. It does not produce additional cardiac or thromboembolic adverse reactions and has no effect on liver function or creatinine. The incidence of grade 3 or 4 neutropenia due to the new drug was 38%, but the incidence of grade 3 or 4 fever with neutropenia was limited to 4%, Prof. Van Cutsem noted. In the combination therapy group, the incidence of grade 3 anemia was 18% and grade 3 or 4 thrombocytopenia was 5%.