我们的目的是调查导致错配修复蛋白缺陷 (d-MMR) 胃癌 (GC) 患者接受纳武单抗联合化疗 (纳武单抗化疗) 治疗时导致不同临床结果的临床病理因素。这项回顾性研究纳入了 28 名 d-MMR 晚期 GC 患者接受一线纳武单抗化疗。作为对照组，纳入了 68 名仅接受一线化疗的患者。分析临床病理因素，包括中性粒细胞与淋巴细胞比率（NLR）和 PD-L1 联合阳性评分（CPS），与疗效结果相关。无进展生存期（PFS）更长（中位 PFS；未达到 [ NR] vs. 5.2 个月，风险比 [HR] 0.28，P < 0.001），并且接受以下治疗的患者的总生存期 (OS) 往往更长（中位 OS；NR vs. 17.9 个月，HR 0.43，P = 0.057）纳武单抗化疗优于化疗。在 NLR 较低 (< 3.80 [中位 NLR]) (HR 0.10) 的亚组中，纳武单抗化疗相对于化疗的 PFS 获益明显，而在 NLR 高 (≥3.80) (HR 0.58) 的患者中则不太明显。在接受纳武单抗化疗的患者中，NLR 较高（≥3.80）的患者的 PFS 比 NLR 较低（< 3.80）的患者更差，PD-L1 CPS ≥ 5 和 < 5 的患者的生存结果相似。在 d-MMR GC 患者中，纳武单抗化疗比单独化疗具有更好的疗效，但对于高 NLR 患者，即使接受纳武单抗化疗，生存结果也很差。根据 PD-L1 CPS，接受纳武单抗化疗的 d-MMR 患者的生存结果没有差异。© 2024。作者获得国际胃癌协会和日本胃癌协会的独家许可。

We aimed to investigate clinicopathologic factors leading to different clinical outcomes in patients with deficient mismatch repair protein (d-MMR) gastric cancer (GC) treated with nivolumab plus chemotherapy (nivolumab chemotherapy).This retrospective study included 28 patients with d-MMR advanced GC treated with first-line nivolumab chemotherapy. As a control group, 68 treated with first-line chemotherapy alone were included. Clinicopathological factors, including the neutrophil-to-lymphocyte ratio (NLR) and PD-L1 combined positive score (CPS), were analyzed with regards to the efficacy outcomes.Progression-free survival (PFS) was longer (median PFS; not reached [NR] vs. 5.2 months, hazard ratio [HR] 0.28, P < 0.001), and overall survival (OS) tended to be longer (median OS; NR vs. 17.9 months, HR 0.43, P = 0.057) in patients treated with nivolumab chemotherapy than those treated with chemotherapy. The PFS benefit of nivolumab chemotherapy over chemotherapy was pronounced in the subgroup with a lower NLR (< 3.80 [median NLR]) (HR 0.10), whereas it was less prominent in patients with a high NLR (≥ 3.80) (HR 0.58). Among patients treated with nivolumab chemotherapy, PFS was worse in patients with a higher NLR (≥ 3.80) than in those with a lower NLR (< 3.80), and survival outcomes were similar between those with PD-L1 CPS ≥ 5 and < 5.Nivolumab chemotherapy was associated with better efficacy outcomes than chemotherapy alone among patients with d-MMR GC, but survival outcomes were poor even with nivolumab chemotherapy for those with a high NLR. Survival outcomes were not different according to PD-L1 CPS among d-MMR patients treated with nivolumab chemotherapy.© 2024. The Author(s) under exclusive licence to The International Gastric Cancer Association and The Japanese Gastric Cancer Association.