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Purpose This study aims to investigate the efficacy and safety of PD-1/PD-L1 inhibitors in the first-line treatment of esophageal squamous cell carcinoma (ESCC) and identify factors influencing efficacy through a meta-analysis of multiple phase 3 randomized controlled trials (RCTs). Methods A systematic literature search was conducted in Cochrane, PubMed, and Embase databases. Two researchers independently extracted trial data, including efficacy-related outcomes such as overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and duration of response (DoR), along with their subgroup data and safety-related indicators. The overall hazard ratio (HR) and 95% confidence interval (CI) were calculated for OS and PFS, while the overall odds ratio (OR) and 95% CI were computed for ORR to compare the classification and predictive abilities of combined positive score (CPS) and tumor proportion score (TPS) for PD-L1 status. Additionally, survival outcomes across different subgroups were evaluated to explore the potential influencing factors for the efficacy of PD-1/PD-L1 inhibitors in ESCC. Results This meta-analysis included eight phase 3 RCTs encompassing 4,479 participants. PD-1/PD-L1 inhibitors combined with chemotherapy significantly improved OS ( HR : 0.68, 95% CI : 0.63-0.74) and PFS ( HR : 0.62, 95% CI : 0.58-0.67) in ESCC patients compared to non-combination therapy. Patients with higher PD-L1 expression (CPS1 or TPS1) demonstrated superior responses to PD-1/PD-L1 inhibitions, with CPS identified as a stronger predictor of therapeutic benefit, particularly at a threshold of CPS =10. Subgroup analysis revealed that male, Asian, smoking, and liver metastasis patients exhibited a greater trend toward improved disease control with PD-1/PD-L1 inhibitors. However, there was no significant difference in treatment efficacy between immune therapy combined with TP (taxol paclitaxel + cisplatin) and FP (5-fluorouracil 5-FU + cisplatin) regimens ( P OS =0.51, P PFS =0.11). Finally, PD-1/PD-L1 inhibition was associated with a higher incidence of grade ≥3 adverse events compared to chemotherapy alone ( HR : 1.21, 95% CI : 1.07-1.37). Conclusions This study confirms that the combination of PD-1/PD-L1 inhibitors and chemotherapy provides significant clinical benefits in ESCC. CPS =10 serves as a key threshold for predicting treatment response. There is a trend suggesting that male, Asian, smoking, and liver metastasis patients may experience better survival benefits, while no significant difference was observed between TP- and FP-based regimens. Systematic Review Registration https://www.crd.york.ac.uk/prospero , identifier CRD42024536221
Ren et al. (Wed,) studied this question.