Pembrolizumab as first-line treatment for recurrent or metastatic head and neck squamous cell carcinoma: a multi-institutional DAHANCA cohort study

Background and purpose: Pembrolizumab is frequently used for recurrent or metastatic head and neck squamous cell carcinoma (rmHNSCC) as first-line treatment. This study evaluates real-world effectiveness in a Danish and United Kingdom (UK) cohort. Patient/material and methods: Patients with confirmed rmHNSCC treated with pembrolizumab (2020–2024) as first-line palliative treatment were included consecutively. Data were collected from patient files at four Danish head and neck cancer centres (discovery cohort) and the Leeds Teaching Hospitals NHS Trust (comparison cohort). Primary endpoints were overall survival (OS) and progression-free survival (PFS). Results: In the discovery cohort (n = 228), a median OS of 10 months (95% confidence interval [CI: 10–12) and median PFS of 4 months (95% CI: 4–6) were found. Primary endpoints did not differ significantly between the discovery and comparison cohort. Baseline World Health Organization performance status appeared to negatively impact endpoints (hazard ratio: 1.4 95% CI: 1.0–2.0). Interpretation: In this real-world multi-centre study, pembrolizumab demonstrated efficacy equivalent to the registration studies in two independent cohorts.