Early assessment of IL8 and PD1+ Treg predicts response and guides treatment monitoring in cemiplimab-treated cutaneous squamous cell carcinoma.

Purpose: Anti-programmed cell death 1 (PD1) is the first-choice treatment in patients with advanced cutaneous squamous cell carcinoma (cSCC), when curative options are unavailable. However, reliable biomarkers for patient selection are still lacking.

Experimental Design: In this translational study, clinical annotations, tissue and liquid biopsies were acquired to investigate the association between sustained objective responses and transcriptional profiles, immune cell dynamics in tumor tissue and peripheral blood samples, as well as circulating cytokine levels.