Pembrolizumab: first anti-PD-1/L1-based regimen for first-line treatment of advanced esophageal cancer in Japan

INTRODUCTION: Esophageal cancer (EC) is the ninth most common cancer in Japanese men. Esophageal squamous cell carcinoma (ESCC) is the major histological type and accounts for 90% of EC cases in Japan. The prognosis of advanced ESCC remains poor. The standard treatment for advanced ESCC was palliative chemotherapy with 5-fluorouracil plus cisplatin as first-line chemotherapy. After failure of first-line chemotherapy, taxanes were used as second-line chemotherapy. Recently, pembrolizumab monotherapy has demonstrated benefits as a second-line treatment in patients with advanced ESCC and a combined positive score of ≥10. Survival was found to be improved in patients with advanced EC who received first-line treatment with pembrolizumab plus doublet chemotherapy than in those who received doublet chemotherapy alone. AREAS COVERED: This overview of immune checkpoint inhibitors focuses on pembrolizumab in combination with chemotherapy and shares key clinical data relevant to the treatment of patients with EC in Japan. EXPERT OPINION: Pembrolizumab plus doublet chemotherapy is now an established first-line treatment for advanced EC in Japan. Recently, nivolumab plus doublet chemotherapy and nivolumab plus ipilimumab have also become first-line treatment options for patients with advanced ESCC. Further investigations are needed to identify biomarkers that would be useful for selecting candidates for these treatments.