Perioperative treatment in resectable gastric cancer with spartalizumab in combination with fluorouracil, leucovorin, oxaliplatin and docetaxel (FLOT): a phase II study (GASPAR)

BACKGROUND: Perioperative chemotherapy and surgery are a standard of care for patients with resectable gastric or gastroesophageal junction (GEJ) adenocarcinoma. However, the prognosis remains poor for this population. The FLOT (fluorouracil, leucovorin, oxaliplatin, and docetaxel) regimen is considered as the new standard chemotherapy regimen for perioperative strategy, despite associated with a 5-year overall survival rate (OS) amounting 45% following radical surgery. Immunotherapy with antibodies that inhibit PD-1/ PD-L1 interaction has recently emerged as a new treatment option with promising and encouraging early trial results for patients with advanced or metastatic gastric or GEJ adenocarcinoma. Currently, no trials have investigated the impact of perioperative immunotherapy in combination with chemotherapy for resectable gastric or GEJ adenocarcinoma. METHODS: GASPAR trial is a multicenter open-label, nonrandomized, phase II trial to evaluate the efficacy and safety of Spartalizumab in combination with the FLOT regimen as perioperative treatment for resectable gastric or GEJ adenocarcinoma. The main endpoint is the proportion of patients with pathological complete regression (pCR) in the primary tumour after preoperative treatment. Systemic treatment will include a pre-operative neoadjuvant and a post-operative adjuvant treatment, during which FLOT regimen will be administered every two weeks for 4 cycles and Spartalizumab every four weeks for 2 cycles. For patients with confirmed tumor resectability on imaging assessment, surgery will be realized within 4–6 weeks after the last dose of preoperative chemotherapy. Post-operative systemic treatment will then be initiated within 4–10 weeks after surgery. Using a Simon’s two-stage design, up to 67 patients will be enrolled, including 23 in the first stage. DISCUSSION: Currently, no trials have investigated the impact of immunotherapy in combination with FLOT chemotherapy as perioperative treatment for resectable gastric or GEJ adenocarcinoma. Some studies have suggested a change in the tumor immune micro-environment following neoadjuvant chemotherapy in this setting, reinforcing the relevance to propose a phase II trial evaluating efficacy and safety of Spartalizumab in combination with perioperative chemotherapy, with the aim of improving treatment efficacy and survival outcomes. TRIAL REGISTRATION: NCT04736485, registered February, 3, 2021.