Efficacy and safety of anti-PD-1 monotherapy and combination therapy in Chinese advanced Gastric cancer: a real-world study

Purpose: Anti-PD-1 inhibitor, pembrolizumab, has been approved for the treatment of locally advanced or metastatic gastric or gastroesophageal junction cancer (GC/GEJC) patients. Our study aimed to evaluate the efficacy and safety profile of anti-PD-1-based treatment in Chinese advanced or metastatic GC/GEJCs and population with poor clinical conditions in a real-world setting.Methods: A retrospective cohort study was conducted and 54 patients were identified and included in our analysis, including 19 patients treated with anti-PD-1 monotherapy and 35 patients treated with anti-PD-1 combination therapy. Demographic and clinical information were evaluated. Clinical response, survival outcomes and safety profile were measured and analyzed. Results: In overall cohort, median overall survival (OS) was 11.10 months (95%CI, 7.05-15.15) and median progression-free survival (PFS) was 3.93 months (95%CI, 2.47-5.39). 16.7% patients reached clinical response and 72.2% patients got disease control. Prolonged OS and PFS and increased clinical response were observed in combination group compared with monotherapy group, although statistical significance was not reached. In subgroups with live metastases or elevated baseline NLR level, combination therapy outperformed anti-PD-1 alone in survival outcomes. 50% and 16.7% of the overall cohort experienced treatment-related adverse events (TRAEs) of any grade and grade 3-5. Conclusions: Anti-PD-1-based monotherapy and combination therapy showed favorable survival outcomes and manageable safety profile in advanced or metastatic GC/GEJCs. Specific population might benefit from combination therapy. Further study with larger sample size is needed.