Presentation (CTI)

OBJECTIVES: Serplulimab is the first anti-PD-1 monoclonal antibody approved globally for perioperative treatment of gastric/gastro-oesophageal junction adenocarcinoma. This study aimed to simulate the long-term health outcomes of neoadjuvant serplulimab plus SOX chemotherapy followed by adjuvant serplulimab versus perioperative SOX chemotherapy from the perspective of the healthcare system in China.
METHODS: A semi-Markov model consisting of four health states (event-free survival, first progressive disease, second progressive disease, and death) was constructed to project long-term health outcomes. The model adopted a 10-year time horizon with a 3-week cycle length. Clinical efficacy and safety data for perioperative therapy were primarily derived from the phase III ASTRUM‑006 trial, while those for first-line therapy (sintilimab plus XELOX or XELOX) were extrapolated from the ORIENT-16 trial. Parameters of utilities were derived from published literature.
RESULTS: In the base-case analysis, where the serplulimab group received XELOX and the SOX group received sintilimab plus XELOX as first-line therapy, the serplulimab group yielded an incremental gain of 0.53 (6.02 vs. 5.49) life years (LYs) and 0.70 (5.18 vs. 4.48) quality-adjusted life years (QALYs), compared with the SOX group. Patients in the serplulimab group spent more time in the event-free survival state (5.78 vs. 4.76 years) and less time in the first (0.19 vs. 0.61 years) progressive disease states. In a scenario analysis assuming both groups received XELOX as first-line therapy, the serplulimab group yielded an incremental gain of 0.69 (6.18 vs. 5.49) LYs and 0.77 (5.25 vs. 4.48) QALYs. Additionally, the mean event-free survival was 5.78 vs. 4.76 years.
CONCLUSIONS: Serplulimab could confer greater health benefits compared to perioperative SOX chemotherapy for PD‑L1‑positive, locally advanced, resectable gastric or gastro‑oesophageal junction adenocarcinoma patients in China. These benefits were primarily driven by prolonged event-free survival and the lower incidence of adverse events in the serplulimab group.