The impact of combined PD-L1 positive score on clinical response to nivolumab in patients with advanced esophageal squamous cell carcinoma

Abstract PurposeNivolumab is recommended for patients with advanced esophageal squamous cell carcinoma (aESCC) who are refractory or intolerant to fluoropyrimidine-based and platinum-based chemotherapy regardless of tumor proportion score (TPS). However, the predictive role of combined positive score (CPS) to predict nivolumab efficacy is unclear.MethodsWe retrospectively collected data from patients with aESCC, who were previously treated with fluoropyrimidines and platinum, and subsequently received nivolumab monotherapy between January 1, 2014 and September 15, 2020. Next, we examined the impact of CPS and TPS on clinical response to nivolumab. The inclusion criteria were refraction or intolerance to fluoropyrimidines and platinum, absence of comorbid malignancies, availability of tissue specimen for immunohistochemistry and programmed cell death-1 analysis results before initiating nivolumab.ResultsFifty patients were included (CPS, ≥ 10/1–10/< 1, n = 23/18/9; TPS, ≥ 10/1–10/< 1%, n = 17/8/25). The median progression-free survival were 4.1, 2.5, and 1.4 months in CPS ≥ 10, 1–10 (hazard ratio [HR] vs. CPS ≥ 10, 1.05; p = 0.90), and < 1 (HR vs. CPS ≥ 10, 3.75; p = 0.003) groups, respectively. Furthermore, among the patients with CPS ≥ 10/1–10/< 1, and TPS ≥ 10/1–10/< 1%, objective response rate were 32/25/0% and 36/0/19%. In addition, disease control rate were 63/50/11% (p = 0.04) and 65/40/38% (p = 0.30).ConclusionsThis study proposes that CPS can predict responses to nivolumab in patients with aESCC better than TPS, making it especially useful for predicting negative outcomes for those with CPS < 1.