Randomised phase II trial of trifluridine/tipiracil (FTD/TPI) plus ramucirumab (RAM) versus trifluridine/tipiracil for previously treated patients with advanced gastric or esophagogastric junction adenocarcinoma (RETRIEVE study, WJOG15822G)

Background: Trifluridine/tipiracil (FTD/TPI) prolongs survival in the third- or later-line treatment for advanced gastric cancer (GC), esophagogastric junction (EGJ) adenocarcinoma, and colorectal cancer. While single-arm phase II trials showed promising outcomes of FTD/TPI plus ramucirumab (RAM) as third- or later-line treatments for advanced GC or EGJ cancer, there have been no clinical trials to directly compare FTD/TPI plus RAM with FTD/TPI monotherapy. Therefore, we have started a randomised phase II trial to evaluate the efficacy and safety of FTD/TPI plus RAM compared with FTD/TPI monotherapy as third- or later-line treatments in patients with advanced GC and EGJ adenocarcinoma. Methods: This RETREVE trial (WJOG15822G) is a prospective, open-label, randomised, multicentre phase II trial comparing FTD/TPI plus RAM versus FTD/TPI monotherapy in a third- or later-line setting. Eligibility criteria include age of > 20 years; performance status of 0 or 1; unresectable or recurrent gastric or EGJ adenocarcinoma; confirmed HER2 status; refractory or intolerant to fluoropyrimidine, taxane or irinotecan; refractory to RAM (not intolerant); and at least a measurable lesion per RECIST 1.1. FTD/TPI (35 mg/m² twice daily, evening of day 1 to morning of day 6 and evening of day 8 to morning of day 13) was administered orally every 4 weeks, and RAM (8 mg/kg) was administered intravenously every 2 weeks. The primary endpoint is progression-free survival (PFS), and the secondary endpoints are overall survival, objective response rate, disease control rate, and safety. The expected hazard ratio of PFS is set as 0.7, assuming 4-month PFS rate of 27% in FTD/TPI monotherapy and 40% in FTD/TPI plus RAM. The number of subjects was 110, with a one-sided alpha error of 0.10 and power of 0.70. Discussion: This study will clarify the additional effect of RAM continuation beyond disease progression on FTD/TPI in the third- or later-line setting for patients with advanced GC or EGJ cancer. Trial registration: jRCTs041220120.