Abstract PO-035: Immune profiles of long-term survivors of patients with head and neck squamous carcinoma on immune checkpoint inhibitor therapy

Abstract Background: Only 15 – 20% of patients with head and neck squamous cell carcinoma (HNSCC) have response to anti-programmed cell death (PD)-1 immunotherapy and there remain gaps in predicting which patients will respond. Method: Here, we utilized DNA methylation cytometry to sequentially delineate detailed immune profiles of six patients with HNSCC (n=38 samples), who had durable response to immunotherapy over a one-year period without disease progression. Results: During the initial 3.5 months of anti-PD-1 immunotherapy treatment, increases in levels of CD8 T memory cells and natural killer cells were observed. Compared to healthy populations in similar age ranges, CD4 T and B cell levels were lower, while monocyte levels were higher in patients with HNSCC at baseline and throughout the year of treatment with immunotherapy. Conclusions: Our results suggest monitoring changes in immune cell type levels as potential biomarkers for patients with HNSCC who respond to anti-PD-1 immunotherapy. Citation Format: Brock Christensen, Min Kyung Lee, Ze Zhang, Rondi Butler, Geat Ramush, Kartik Sehgal, Keisuke Shirai, Devin Koestler, Lucas Salas, John Wiencke, Robert Haddad, Karl Kelsey. Immune profiles of long-term survivors of patients with head and neck squamous carcinoma on immune checkpoint inhibitor therapy [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Innovating through Basic, Clinical, and Translational Research; 2023 Jul 7-8; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2023;29(18_Suppl):Abstract nr PO-035.