Zolbetuximab, Durvalumab, and FLOT Combination Neoadjuvant Chemotherapy for CLDN18.2-Positive Gastric Cancer or Gastroesophageal Junction Adenocarcinoma (Zodiac-Neo)

Claudin 18.2 (CLDN18.2) is a molecular target expressed in a subset of gastric and gastroesophageal junction (GEJ) adenocarcinomas. Zolbetuximab, a chimeric monoclonal antibody targeting CLDN18.2, has shown clinical benefit in combination with chemotherapy for CLDN18.2-positive unresectable advanced or recurrent gastric cancer, and in Japan, FLOT plus durvalumab is expected to become a standard perioperative treatment for locally advanced gastric/GEJ adenocarcinoma. This trial evaluates whether adding zolbetuximab to FLOT plus durvalumab further improves the pathological response of neoadjuvant chemotherapy in CLDN18.2-positive, locally advanced, resectable gastric or GEJ adenocarcinoma. This is a single-arm, open-label, multicenter, investigator-initiated phase II trial conducted at four sites in Japan. Eligible participants are adults (18 years or older) with previously untreated (no prior chemotherapy, radiotherapy, or immunotherapy), histologically confirmed gastric or GEJ adenocarcinoma classified as cT2-4 and/or cN+, M0 by the UICC/TNM Classification (8th edition), confirmed…

• Histological complete response rate (Grade 3), per central pathological review

1. Primary completion expected

   31 Mar 2030

2. Registered

   14 Oct 2026

3. Started

   13 Aug 2026