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

Abstract

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). 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. 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. Among patients with advanced or metastatic ESCC, camrelizumab combined with apatinib showed a reasonable remission rate and survival benefit with a manageable safety profile.