Study details
Patients in TAGS were randomized 2:1 to trifluridine/tipiracil (formerly TAS-102) or placebo, each added to best supportive care. (Trifluridine is a novel oral thymidine analogue, and tipiracil prevents trifluridine degradation.) Overall, 44% had undergone gastrectomy before entering the trial.
In the entire trial population, overall survival was 5.7 months with trifluridine/tipiracil and 3.6 months with placebo (hazard ratio, 0.69; 95% confidence interval, 0.56-0.85; P = .0006), as previously reported.
Among the subgroup who had undergone prior gastrectomy, overall survival was 6.0 months with trifluridine/tipiracil and 3.4 months with placebo (HR, 0.57; 95% CI, 0.41-0.79), Dr. Ilson reported at the symposium, which is sponsored by the American Gastroenterological Association, the American Society for Clinical Oncology, the American Society for Radiation Oncology, and the Society of Surgical Oncology. The combination also netted better progression-free survival (2.2 vs. 1.8 months; HR, 0.48; 95% CI, 0.35-0.65). “These data mirror the data seen in the overall treatment population,” he commented.
In a multivariate analysis including all prespecified factors, prior gastrectomy was neither prognostic nor predictive. Moreover, the treatment effect size remained the same after adjustment for potential prognostic factors.
Exposure to trifluridine/tipiracil was similar for the gastrectomy subgroup and the entire trial population in terms of relative dose intensity, median number of cycles, and treatment duration.
The rate of grade 3 or 4 treatment-related adverse events with trifluridine/tipiracil in the gastrectomy subgroup, 64%, was higher than that in the entire trial population, 53%, but the rate of discontinuation because of any-grade adverse events was similar, at 10% and 13%, respectively.
The difference in grade 3 or 4 adverse events between the gastrectomy subgroup and the entire trial population was mainly driven by higher rates of neutropenia (44% vs. 34%) and leukopenia (14% vs. 9%) in the former.
Dr. Ilson disclosed that he has a consulting role with Amgen, Astellas, AstraZeneca, Bayer, Bristol-Myers Squibb, Lilly, Merck, Pieris, Roche/Genentech, and Taiho and that he receives research support from Taiho. The study was funded by Taiho Oncology and Taiho Pharmaceutical.
SOURCE: Ilson DH et al. 2019 GI Cancers Symposium, Abstract 3.