Survival outcomes of patients with gastric cancer treated with first-line nivolumab plus chemotherapy based on claudin 18.2 expression.

backgroundClaudin 18.2 has emerged as a viable therapeutic target in gastric cancer; however, its clinical relevance in the context of immune checkpoint inhibitor-based chemotherapy is not known. This study aimed to investigate the efficacy of nivolumab plus chemotherapy according to claudin 18.2 expression in patients with gastric cancer.

methodsThis single-center study included patients with advanced gastric cancer who were treated with first-line nivolumab plus chemotherapy (n = 204) or chemotherapy alone (n = 183) whose claudin 18.2 immunohistochemistry results were available. Claudin 18.2 positivity (moderate-to-strong expression in ≥ 75% by the 43-14A clone) was analyzed in terms of efficacy outcomes.

resultsAmong patients treated with nivolumab plus chemotherapy, 96 (47.1%) were assessed to have claudin 18.2-positive tumors. Between patients with claudin 18.2-positive and -negative tumors, objective response rate with nivolumab plus chemotherapy was comparable. Progression-free survival (PFS) and overall survival (OS) with nivolumab plus chemotherapy were comparable between those with claudin 18.2-positive and -negative tumors. For both subgroups with PD-L1 combined positive score ≥ 5 and < 5, PFS and OS with nivolumab plus chemotherapy were also comparable between patients with claudin 18.2-positive and -negative tumors. A consistent trend of favorable PFS and OS was observed with nivolumab plus chemotherapy compared to that of chemotherapy alone in both claudin 18.2-positive and -negative subgroups.

conclusionThe efficacy of nivolumab plus chemotherapy did not vary according to claudin 18.2 positivity. The clinical benefit of nivolumab plus chemotherapy over chemotherapy was consistently observed in claudin 18.2-positive and -negative gastric cancer cases.