A Phase II Study of Apatinib in Patients with Chemotherapy-Refractory Esophageal Squamous Cell Carcinoma (ESO-Shanghai 11)

Lessons learned: Apatinib has potential as an effective and safe second-line or higher treatment for patients with chemotherapy-refractory esophageal squamous cell carcinoma (ESCC). Clinical safety is of potential concern when administering apatinib to patients with uncontrolled esophageal lesions or severe invasion of trachea, bronchi, or major blood vessels. To the best of the authors' knowledge, this is the first prospective phase II study to investigate apatinib for patients with chemotherapy-refractory ESCC. Apatinib could provide an alternative option for ESCC after first-line or higher therapy in carefully selected patients.

Background: The aim of this study was to evaluate the efficacy and adverse effects of the oral vascular endothelial growth factor receptor 2 (VEGFR-2) tyrosine kinase inhibitor apatinib in patients with chemotherapy-refractory esophageal squamous cell carcinoma (ESCC).

Methods: We enrolled patients with chemotherapy-refractory ESCC. All patients received continuous apatinib 500 mg once daily.

Results: Between July 2017 and August 2018, 40 patients were recruited, of whom 5 (12.5%) had uncontrolled primary tumors. Additionally, three patients with partial response (PR) and 23 with stable disease (SD) were observed for overall response rate (ORR) of 7.5% and disease control rate (DCR) of 65.0%. Median progression-free survival (PFS) was 3.8 months (95% confidence interval [CI], 2.2-5.4); median overall survival (OS) was 5.8 months (95% CI, 3.2-8.4). Common adverse effects were fatigue (15%), hypertension (12.5%), and palmar-plantar erythrodysesthesia syndrome (10%). Two cases of death from massive bronchopulmonary hemorrhage were observed, and esophageal fistula occurred in another two patients. Notably, both patients with esophageal fistula and one patient with massive fatal bronchopulmonary hemorrhage were individuals with uncontrolled primary tumors (3/5, 60%). Fatal bronchopulmonary hemorrhage in a second patient was associated with major blood vessel invasion.

Conclusion: Apatinib has potential as an effective and safe treatment for patients with chemotherapy-refractory ESCC whose primary tumors are controlled and without severe invasion of trachea, bronchi, or major blood vessels.