Camrelizumab combined with apatinib for unresectable, metastatic esophageal squamous cell carcinoma: a single-center, single-arm, prospective study.

Background: The prognosis for esophageal cancer (EC), a common malignant tumor, is poor. The new oral small-molecule tyrosine kinase inhibitor apatinib has shown an excellent therapeutic effect on treating EC. Camrelizumab is a humanized programmed death 1 (PD-1) inhibitor with high affinity. Immune checkpoint inhibitors combined with chemotherapy have become the standard first-line treatment for advanced EC. The new combination strategy of anti-angiogenic therapy combined with immunotherapy has great application prospects in the treatment of tumors. We aimed to assess camrelizumab in combination with apatinib as a new combination regimen for advanced or metastatic esophageal squamous cell carcinoma (ESCC). Methods: In this study, we recruited patients with an Eastern Cooperative Oncology Group (ECOG) performance status ≤2, with pathologically confirmed unresectable, locally advanced, locally recurrent, or metastatic ESCC. Each patient received an intravenous infusion of camrelizumab 200 mg and oral administration of apatinib 250 mg once a day, every 21 days, as a cycle until disease progression, intolerance, or death. The primary endpoint was the objective response rate (ORR), while the Kaplan-Meier method and LIFETEST procedure were used to estimate survival functions for overall survival (OS) and progression-free survival (PFS). The National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.03, was used to evaluate adverse events. Results: Between December 1, 2019 and July 31, 2022, 35 patients were enrolled, with 29 patients in the efficacy and safety analysis. The ORR was 34.5%, and the disease control rate (DCR) reached 82.8%. Median OS was 13.8 months (95% CI: 11.2-16.2), and the estimated 6-, 9-, and 12-month OS rates were 85.5% (95% CI: 65.7-94.3%), 80.9% (95% CI: 60.3-91.5%), and 67.0% (95% CI: 43.8-82.4%), respectively. Median PFS was 9.5 months (95% CI: 7.0-13.6). The most prominent grade ≥3 adverse events associated with treatments were alanine aminotransferase (ALT) increase (10.3%), hypertension (10.3%), and reactive cutaneous capillary endothelial proliferation (CCEP) (6.9%), and no deaths occurred due to adverse events. Conclusions: Among patients with advanced or metastatic ESCC, camrelizumab combined with apatinib showed a reasonable remission rate and survival benefit with a manageable safety profile.