Abstract
BACKGROUND: Trastuzumab plus chemotherapy is the standard-of-care (SoC) first-line therapy for HER2-positive advanced gastric cancer. Combining PD-1 antibody with SoC first-line therapy showed encouraging results in the KEYNOTE-811 study. The retrospective study aims to evaluate the efficacy and safety of SoC vs. SoC plus camrelizumab (PD-1 antibody) as a first-line treatment for HER2-positive advanced gastric cancer in a real-world setting. METHODS: This study included 41 patients with HER2-positive advanced gastric cancer who received SoC or SoC plus camrelizumab from June 2017 to December 2020. The endpoints were objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety. RESULTS: Thirteen patients received SoC (SoC group) and 28 patients received SoC plus camrelizumab (camrelizumab group). As of December 2020, the median follow-up time was 10.0 months. In the camrelizumab and SoC groups, the ORRs were 75.0% and 46.2% (P=0.032), respectively. The DCR was 96.4% in the camrelizumab group and 69.2% in the SoC group (P=0.003). The median OS was 18.4 in the camrelizumab group and 13.2 months in the SoC group [hazard ratio (HR) =0.343; 95% confidence interval (CI): 0.151-0.783; P=0.008]. The median PFS was 3.78 in the camrelizumab group and 1.74 months in the SoC group (HR =0.416; 95% CI: 0.186-0.932; P=0.027). In the HER2 subgroups in the camrelizumab group, the median PFS of immunohistochemistry (IHC) 3+ vs. IHC 2+ fluorescence in situ hybridization (FISH) was 11.3 vs. 9.0 months (HR =1.684; 95% CI: 0.710-3.994; P=0.047). The incidence rates of reactive cutaneous capillary endothelial proliferation (RCCEP) (P<0.001), abnormal liver function (P=0.040), and hypothyroidism (P=0.039) between the two groups were significantly different. RCCEP and hypothyroidism were considered to be related to camrelizumab. CONCLUSIONS: First-line treatment with camrelizumab combined with SoC showed significant clinical benefits and good tolerance compared with SoC for HER2-positive advanced gastric cancer.