Background: The phase 3 study TAGS demonstrated that the novel oral therapy FTD/TPI (TAS-102) represents an effective treatment option with a manageable safety profile for pts with heavily pretreated mGC. In an earlier single-arm Japanese phase 2 trial in mGC, no differences were found in the pharmacokinetics of either FTD or TPI in pts with or without prior gastrectomy. We evaluated the efficacy and safety of FTD/TPI in pts with or without prior gastrectomy within the TAGS study. Methods: In this global phase 3 study of adult pts with mGC who had received ≥ 2 prior regimens of chemotherapy, pts were randomized 2:1 to receive FTD/TPI (35 mg/m² BID on days 1–5 and 8–12 of each 28-day cycle) or placebo, plus best supportive care. We performed a preplanned analysis of efficacy and safety endpoints in pt subgroups with or without prior gastrectomy. Results: Of 507 randomized pts, 221 (44%) had a prior gastrectomy (FTD/TPI, 147/337; placebo, 74/170). Baseline pt characteristics were balanced across pt subgroups. FTD/TPI prolonged survival versus placebo regardless of gastrectomy (table). The frequency of neutropenia/leukopenia appeared to be higher among FTD/TPI-treated pts with vs without gastrectomy, but this did not result in more treatment discontinuations (table). Conclusions: In the TAGS study, subgroup analysis demonstrated that FTD/TPI is an effective treatment option with a manageable safety profile for pts with heavily pretreated mGC, regardless of prior gastrectomy. Clinical trial information: NCT02500043

^aOccurring in ≥10% of pts in any group