Background: Several studies have shown that combining immune checkpoint inhibitors (ICIs) with antiangiogenic tyrosine kinase inhibitors is effective for solid tumors, including esophageal squamous cell carcinoma (ESCC). However, most of these studies were focused on immunotherapy-naive patients. This retrospective real-world study offers insights into the efficacy and safety of combining anlotinib with ICIs in locally advanced/metastatic ESCC patients who progressed on prior ICI.
Methods: We retrospectively analyzed the efficacy and safety of anlotinib plus PD-1 inhibitor in locally advanced/metastatic ESCC patients who had progressed on PD-1 inhibitor. Efficacy was assessed according to the Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1). The primary endpoints were the objective response rate (ORR) and disease control rate (DCR), while secondary endpoints were safety, overall survival (OS) and progression-free survival (PFS). Baseline characteristics and adverse events (AEs) were documented throughout the study.
Results: Between July 2020 and March 2022, 29 eligible patients were included in the final analysis, with 23 (79.3%) having previously undergone resection for ESCC. Of these 29 patients, 8 (27.6%) received first-line systemic therapy, 20 (69.0%) received second-line therapy, and 1 patient (3%) received third-line therapy. At the data cutoff, the ORR was 31.0%, and the DCR was 86.2%, with 9 patients achieving partial response (PR), 16 patients with stable disease (SD) and 4 patients with disease progression (PD). The median PFS was 5.33 months (95% CI: 4.28-6.38), and the median OS was 10.37 months (95% CI: 6.26-14.46). All patients experienced treatment-related adverse events (TRAEs), with anemia and lymphopenia being the most common. Only 2 patients (6.9%) experiencing grade 3-4 lymphopenia. All AEs were managed with symptomatic treatment and no treatment-related deaths occurred.
Conclusion: The combination of anlotinib and a PD-1 inhibitor demonstrated promising antitumor efficacy and manageable toxicity in patients with locally advanced/metastatic ESCC who progressed on prior ICI. This regimen represents a feasible and well-tolerated treatment option for this patient population.
Trial registration number: NCT04984096.
Keywords: Anlotinib; PD-1 inhibitor; combination therapeutic regimen; esophageal squamous cell carcinoma; progressed on prior ICI.