A multicenter retrospective study of PD-1 blockade plus chemotherapy as first-line therapy in advanced hepatoid adenocarcinoma of the stomach

Purpose This study aims to evaluate the efficacy and safety of PD-1 blockade in combination with chemotherapy for patients with advanced hepatoid adenocarcinoma of the stomach (HAS). Materials and methods This study retrospectively collected data from 25 patients with advanced HAS who received first-line PD-1 blockade combined with chemotherapy across 6 centers between January 2018 and January 2024. Progression-Free Survival (PFS) and Overall Survival (OS) were assessed using Kaplan-Meier (KM) curves. Results This study included 25 patients with HAS, all of whom received a first-line treatment regimen combining PD-1 blockade and chemotherapy. The Objective Response Rate (ORR) and Disease Control Rate (DCR) were 76.0% and 88.0%, respectively. The median follow-up time was 13.1 months, with a median Progression-Free Survival (mPFS) of 10.2 months (95% CI: 6.3–14.1) and a median Overall Survival (mOS) of 20.3 months (95% CI: 11.3–29.4). A total of 20 patients (80.0%) experienced adverse reactions of varying degrees, with white blood cell (WBC) count decreased (12, 48.0%) being the most common adverse event. Two patients experienced fatal adverse events (grade 5),both of which were unrelated to the PD-1 blockade. Conclusion Patients with HAS can derive survival benefits from first-line treatment with PD-1 blockade combined with chemotherapy, and the treatment is well tolerated. Furthermore, this pathological subtype may serve as a predictive indicator of favorable efficacy for PD-1 blockade, regardless of the patients' PD-L1 combined positive score (CPS).