This phase II study will evaluate dostarlimab with a watch-and-wait approach for patients with localized mismatch repair deficiency (dMMR)/microsatellite instability (MSI) gastric or oeso-gastric junction adenocarcinoma.
The goal of the study is to determine whether the surgery could be avoided in patients with localized dMMR/MSI-H gastric/OGJ adenocarcinoma with complete response at endoscopy and biopsies free of tumoral cells after treatment with dostarlimab, with a watch-and-wait approaches.
Capable of giving signed and dated informed consent,
An ECOG PS of 0-1,
≥18 and ≤75 years old,
The patient's G8 questionnaire score is above 14 AND
Prior concomitant unplanned antitumor therapy (e.g., chemotherapy, molecular targeted therapy, immunotherapy),
Treatment with any investigational medicinal product within 28 days prior to study entry,
Treatment anticoagulant or hemostasis disorder contraindicating - biopsies during endoscopy,
Major surgical procedure within 28 days (4 weeks) prior to the first dose of study treatment,