S903 Efficacy and Safety of Camrelizumab Plus Apatinib for Esophageal Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

Introduction: Esophageal squamous cell carcinoma (ESCC) remains a major global health burden with limited treatment options in advanced stages. Combining immunotherapy with anti-angiogenic agents has shown promise. Camrelizumab, a programmed cell death protein 1 inhibitor, and apatinib, a vascular endothelial growth factor receptor 2 inhibitor, may offer synergistic effects, potentially improving outcomes in patients with advanced or metastatic ESCC. Methods: A literature search was conducted across PubMed, Cochrane, Embase, Scopus, and clinicaltrials.gov from inception until February 2025. Eight studies evaluating the safety and efficacy of camrelizumab plus apatinib were included. The analysis was conducted on R Studio v4.4.5. Pooled estimates were reported as proportions and 95% confidence interval [CI] using the random effect model. Statistical heterogeneity was assessed using I². Subgroup analysis was conducted based on treatment exposure. Results: The pooled 1-year overall survival (OS) from 6 studies was 71% (95% CI 50-89%; I2 = 94.1%), with treatment naïve patients showing a statistically higher 1-year OS of 95% (95% CI 90-98%; I2 = 0%) than 55% (95% CI 41-69; P-value < 0.0001; I2 = 75.7%) in pretreated patients. One-year progression-free survival (PFS) was 25% (13-39; I2 = 72.5%) across 4 studies. Overall response rate was significantly higher in the treatment-naïve group [87% (95% CI 80-93); I2 = 14%] than the previously treated group [28% (95% CI 18-40); I2 = 72.5%]. Previously treated patients showed a modest complete response rate (CRR) of 1% (0-4; I2 = 65%), while treatment-naïve patients showed a significantly higher CRR of 22% (10-36; P-value = 0.0001; I2 = 62.5%). Partial response rate was also significantly higher in the naïve subgroup (64% [53-73%]; I2 = 0% vs 26% [16-37]; I2 = 66.8%; P-value < 0.0001). Treatment-naïve patients also showed significantly higher stable disease (48% [39-56]; I2 = 8.5%, vs 11% [4-23]; I2 = 57.9%). Hemangioma was significantly greater in the treatment-naïve subgroup (47% [25-70] vs 12% [3-24%]; P = 0.0049). Rates of leukopenia (51%), neutropenia (32%), anemia (32%), and thrombocytopenia (30%) were comparable between the 2 subgroups. Conclusion: Treatment-naïve patients showed superior OS and higher response rates. Adverse events were similar between the subgroups, except for a greater risk of hemangioma in the treatment-naïve subgroup. Large-scale trials are warranted to validate these findings and optimize treatment strategies.