PD-L1 expression combined with immune phenotype is a potential predictor of outcome with PD-1 inhibitor monotherapy in patients with recurrent or metastatic head and neck squamous cell carcinoma

Abstract

Objective: Programmed cell death-ligand 1 (PD-L1) expression and immune phenotype (IP) are potential predictive biomarkers for immune checkpoint inhibitors (ICIs) in recurrent and/or metastatic head and neck squamous cell carcinoma (R/M HNSCC). This study evaluated the predictive value of combining PD-L1 expression and IP in R/M HNSCC.

Study design: Forty-one R/M HNSCC patients treated with ICI were included. PD-L1 expression was evaluated using the standardized 22C3 pharmDx assay. IPs were assessed using Lunit SCOPE IO, an artificial intelligence-powered tumor-infiltrating lymphocyte analyzer.

Results: Thirty-nine patients (95.1%) were classified as PD-L1 positive (combined positive score ≥1). Overall, 27 (65.9%) had desert IP. PD-L1 expression and IP were combined to classify patients into 3 groups: group A, negative PD-L1; group B, positive PD-L1 with desert IP; group C, positive PD-L1 with non-desert IP. The median progression-free survival (PFS) was 1.2 months in group A, 2.1 months in group B, and 12.1 months in group C (P = .015). In multivariate Cox analysis, PD-L1 expression combined with IP was an independent factor for PFS, with a hazard ratio of 0.14 (P = .018) in group C and 0.37 (P = .186) in group B, relative to group A.

Conclusions: In R/M HNSCC, integrating IP with PD-L1 expression may enhance prediction of ICI outcomes.