Outcomes and Biomarkers of Immune Checkpoint Inhibitor Therapy in Patients with Refractory Head and Neck Squamous Cell Carcinoma: KCSG HN18-12

Purpose: This study was conducted to determine the effectiveness of immune checkpoint inhibitors (ICIs) in recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) after platinum-containing chemotherapy. We also identified clinical biomarkers which may be predictive of patient prognosis.

Materials And Methods: We analyzed 125 patients with R/M HNSCC who received ICIs, retrospectively. Overall response rate (ORR) was the primary study outcome. Overall survival (OS) and progression-free survival (PFS) were the secondary study outcomes.

Results: The patients received anti-programmed cell death protein-1 (PD-1) (n=73, 58%), anti-programmed death-ligand 1 (PD-L1) (n=24, 19%), or a combination of anti-PD-1/PD-L1 and anti-cytotoxic T-lymphocyte antigen 4 (n=28, 22%). The median age was 57 years (range, 37 to 87). The location of the primary tumor was in the oral cavity in 28% of the cases, followed by oropharynx (27%), hypopharynx (20%), and larynx (12%). The ORR was 15% (19/125). With 12.3 months of median follow-up, median PFS was 2.7 months. Median OS was 10.8 months. A neutrophil-to-lymphocyte ratio (NLR) > 4 was significantly associated with poor response to ICIs (odds ratio, 0.30; p=0.022). A sum of the target lesions > 40 mm (hazard ratio [HR], 1.53; p=0.046] and a NLR > 4 (HR, 1.75; p=0.009) were considered to be predictive markers of short PFS. A poor performance status (HR, 4.79; p < 0.001), a sum of target lesions > 40 mm (HR, 1.93; p=0.025), and an NLR > 4 (HR, 3.36; p < 0.001) were the significant predictors for poor survival.

Conclusion: ICIs exhibited favorable antitumor activity in R/M HNSCC. Clinically, our findings can be used to recognize patients benefit from receiving ICI.