The UK Divide: Does Having a Pembrolizumab-Chemotherapy Option in Head and Neck Cancer Matter? Real-world Experience of First-line Palliative Pembrolizumab Monotherapy and Pembrolizumab-Chemotherapy Combination in Scotland.

AIMS: The Scottish Medical Consortium recently approved first-line pembrolizumab monotherapy or in combination with chemotherapy for head and neck squamous cell carcinoma in the palliative setting, contrasting with the decision made by the National Institute for Health and Care Excellence, who approved monotherapy alone in England and Wales. The aim of this study was to provide real-world performance data for first-line pembrolizumab-containing treatments for head and neck squamous cell carcinoma in the palliative setting in Scotland. MATERIALS AND METHODS: We analysed the electronic records of patients who started pembrolizumab-containing treatment between 1 March 2020 and 30 September 2021. Outcomes included overall survival, progression-free survival (PFS), the duration of response and the disease control rate. Data were compared with the KEYNOTE-048 study and clinical factors were evaluated for association with survival. RESULTS: Our cohort included 91 patients (median follow-up 10.8 months). Patient characteristics were similar to those in the KEYNOTE-048 study, although our cohort had a higher proportion of patients with newly diagnosed, non-metastatic disease. For patients receiving monotherapy (n = 76), 12- and 24-month overall survival were 45% and 27%, respectively. For patients receiving pembrolizumab-chemotherapy (n = 15), 12-month overall survival was 60% (24-month overall survival had not yet been reached). Experiencing one or more immune-related adverse event (irAE; versus no irAEs), of any grade, was associated with favourable overall survival and PFS for patients receiving monotherapy in both univariable Log-rank analysis (median overall survival 17.4 months versus 8.6 months, respectively, P = 0.0033; median PFS 10.9 months versus 3.0 months, respectively, P < 0.0001) and multivariable analysis (Cox proportional hazards regression: overall survival hazard ratio 0.31, P = 0.0009; PFS hazard ratio 0.17, P < 0.0001). CONCLUSION: Our real-world data support the KEYNOTE-048 study findings and the value of combination treatment options. Additionally, our data show that irAEs of any grade, as reported in routine clinical records, are associated with better outcomes in this patient group, adding to the growing body of evidence showing that irAEs are generally a positive marker of programmed death-ligand 1 (PD-L1) inhibitor response.