Abstract
BACKGROUND: In this study, we aimed to evaluate the real-world efficacy and safety of camrelizumab and identify clinicolaboratory factors that predict treatment outcomes in patients with unresectable advanced, recurrent, or metastatic esophageal squamous cell carcinoma (ESCC) receiving camrelizumab. METHODS: Herein, 174 patients with unresectable advanced, recurrent, or metastatic ESCC treated with camrelizumab monotherapy (n = 30), camrelizumab + chemotherapy (CT; n = 91), and camrelizumab + radiotherapy (RT; n = 53) between October 1, 2019 and October 1, 2022 were included. RESULTS: The median follow-up time was 20 months (range, 1-34 months). The median progression-free survival (PFS) and overall survival (OS) of the whole cohort were 8 months [95% confidence interval (CI), 6.5-9.5 months] and 14 months (95% CI, 11.2-16.8 months), respectively. After multivariate analysis, receiving > 4 cycles of camrelizumab was identified as an independent predictor of better PFS [hazard ratio (HR), 0.56; 95% CI, 0.38-0.827; P = 0.004] and OS (HR, 0.532; 95% CI, 0.341-0.83; P = 0.005). An intermediate-to-poor lung immune prognostic index (LIPI) was identified as an independent predictor of worse PFS (HR, 1.505; 95% CI, 1.032-2.196; P = 0.034) and OS (HR, 1.657; 95% CI, 1.094-2.51; P = 0.017). The disease control rate of patients in the camrelizumab monotherapy group, camrelizumab + CT group, and camrelizumab + RT group was 92.3% (95% CI, 74.9-99.1%), 90.6% (95% CI, 82.3-95.9%), and 96.1% (95% CI, 86.8-99.5%), respectively. The treatment-related adverse events (AEs) of grade 3 or higher were reported in 67 patients (38.5%). The most common treatment-related AEs were decreased neutrophil count (23.0%), decreased white blood cell count (19.5%), anemia (7.5%), and pneumonitis (4.6%). One patient (0.6%) died from a treatment-related AE of immune checkpoint inhibitor-induced myocarditis. CONCLUSION: Camrelizumab was safe and effective as both monotherapy and part of a combination therapy. Longer PFS and OS were associated with receiving > 4 cycles of camrelizumab and having a good LIPI. LIPI can be used as a prognostic biomarker for ESCC patients receiving camrelizumab + RT. TRIAL REGISTRATION: ClinicalTrial.gov Identifier: CHICTR2000039499. Registered: 19th October 2020.