Predictive value of peripheral lymphocyte counts for immune checkpoint inhibitor efficacy in advanced head and neck squamous cell carcinoma.

Anti-programmed death 1 (PD-1) immune checkpoint inhibitors (ICI) have revolutionized the treatment of advanced head and neck squamous cell carcinoma (HNSCC) but benefit only a small subset of patients. Several studies have previously assessed the predictive value of peripheral lymphocyte count for ICI therapy responses; however the optimal lymphocyte measure for the best predictive value in HNSCC is unknown. The present study examined the predictive values of multiple peripheral lymphocyte measures for anti-PD-1 ICI therapy in advanced HNSCC. Clinicopathologic data were retrospectively collected on patients with recurrent or metastatic HNSCC who had received anti-PD-1 therapy. The association between clinical outcomes and various peripheral lymphocyte count measures was analyzed, including absolute lymphocyte count (ALC) and neutrophil-to-lymphocyte ratios (NLR) at baseline, week 6, and change from baseline to week 6. The primary outcome of interest was progression-free survival (PFS). A total of 108 patients with HNSCC who had received anti-PD-1 therapy were identified. The median PFS was 4.1 months. Week 6 high ALC (≥0.77) and low NLR (<6.2) were associated with a longer PFS (5.6 vs. 3.1 months, P=0.002; and 8.7 vs. 2.9 months, P=0.001, respectively). Decreased NLR during treatment was also associated with an improved PFS (6.7 vs. 2.7 months; P=0.015). Baseline lymphocyte counts and absolute lymphocyte changes during treatment did not predict ICI outcome. The present single institution retrospective study suggested that ALC and NLR values at week 6, and on-treatment NLR dynamic change have predictive value for anti-PD-1 therapy response.