[Clinical analysis of immunotherapy rechallenge in advanced gastric cancer].

Objective: To evaluate the efficacy and influencing factors of programmed death protein 1 (PD-1) monoclonal antibody rechallenge therapy in advanced gastric cancer (GC). Methods: The clinical data of patients with advanced GC who were treated with anti-PD-1 rechallenge in Henan Cancer Hospital from January 2020 to December 2021 were collected retrospectively. The progression-free survival (PFS) was defined as the time from the first or second used of anti-PD-1 treatment to the date of disease progression or the last follow-up, named PFS(1) and PFS(2), respectively. Kaplan-Meier method and Log rank test were used for survival analysis, Cox proportional hazard model was used to analyze the influencing factors. Results: A total of 60 patients with anti-PD-1 rechallenge therapy were collected, the median follow-up time was 12.2 months. The median progression-free survival (PFS(2)) of anti-PD-1 rechallenge therapy was 2.9 months, the objective response rate (ORR) was 16.7%, and the disease control rate (DCR) was 55.0%. The median PFS(2) of the first and second anti-PD-1 identical and different rechallenge treatment was 3.5 months and 1.9 months (P=0.007) respectively. The median PFS(2) of positive PD-L1 expression in rechallenge therapy was 3.4 months, ORR was 22.7%, and DCR was 63.6%; the median PFS(2) was 4.5 months, ORR was 27.3%, and DCR was 54.5% in patients with median PFS(1)≥6 months. Multivariate analysis showed that peritoneal metastasis was independently associated with anti-PD-1 rechallenge therapy with PFS(2) (HR=2.327, 95% CI, 1.066-5.082, P=0.034). The incidence of adverse reactions in grade 1-2 and grade 3-4 of anti-PD-1 rechallenge therapy was 83.3%, and 35.0%, respectively, and the safety was controllable. Conclusion: Rechallenge therapy with anti-PD-1 is a feasible treatment in advanced GC, but the screening of suitable population for rechallenge therapy still needs prospective data analysis and verification.目的： 探讨程序性死亡受体1(PD－1)单抗再挑战治疗在晚期胃癌中的临床疗效及影响因素。 方法： 回顾性收集2020年1月至2021年12月就诊河南省肿瘤医院使用PD－1单抗再挑战治疗晚期胃癌患者的临床资料。初次或再次使用PD－1单抗治疗开始至疾病进展或末次随访日期的时间为无进展生存时间(PFS)，分别命名为PFS(1)和PFS(2)，生存分析采用Kaplan－Meier法和Log rank检验，预后影响因素分析采用Cox比例风险模型。 结果： 60例PD－1单抗再挑战治疗患者的中位随访时间为12.2个月，中位PFS(2)为2.9个月，客观缓解率(ORR)为16.7%，疾病控制率(DCR)为55.0%。首次及再次使用相同PD－1单抗和不同PD－1单抗挑战治疗的中位PFS(2)分别为3.5和1.9个月(P＝0.007)。再挑战治疗中程序性死亡受体配体1表达阳性患者的中位PFS(2)为3.4个月，ORR为22.7%，DCR为63.6%；中位PFS(1)≥6个月患者的中位PFS(2)为4.5个月，ORR为27.3%，DCR为54.5%。多因素分析显示，腹膜转移是PD－1单抗再挑战治疗PFS(2)的独立影响因素(HR＝2.327，95% CI：1.066~5.082，P＝0.034)。PD－1单抗再挑战治疗中1~2级不良反应发生率为83.3%(50/60)，3~4级为35.0%(21/60)，安全性可控。 结论： 晚期胃癌中PD－1单抗再挑战治疗是一种可行的治疗方式，但再挑战治疗适宜人群的筛选仍需前瞻性数据分析验证。.