Cost-effectiveness of pembrolizumab as neoadjuvant therapy and in combination with standard of care (SOC) as adjuvant therapy for stage III-IVA resectable locally advanced head and neck squamous cell carcinoma (LA HNSCC) in Switzerland

Abstract

AIMS: KEYNOTE-689 trial results demonstrated that neoadjuvant pembrolizumab followed by adjuvant pembrolizumab plus standard of care (NP/AP + SOC) significantly improved event-free survival (EFS) versus SOC alone in patients with locoregionally advanced head and neck squamous cell carcinoma (LA HNSCC). This study evaluated the cost-effectiveness of NP/AP + SOC vs. SOC from the Swiss healthcare perspective. MATERIALS AND METHODS: A 4 mutually exclusive health state US-specific Markov cohort model was adapted to the Swiss healthcare perspective. Efficacy inputs were derived from patient-level KEYNOTE-689 data using parametric survival analysis. Healthcare resource utilisation and costs (2025 Swiss Franc [CHF]) were obtained from Swiss clinical experts and national tariffs. Health state utilities were derived from EuroQoL-5 dimension data collected in KEYNOTE-689. Outcomes included costs, quality-adjusted life-years (QALYs) and life-years (LYs), measured over a lifetime horizon. At the base-case, a 3.0% discount rate was applied to costs and effectiveness. Cost-effectiveness was evaluated as an incremental cost-effectiveness ratio (ICER) at a hypothetical willingness-to-pay (WTP) threshold of CHF 100,000/QALY gained. Deterministic, probabilistic, and scenario analyses were conducted for sensitivity. RESULTS: NP/AP + SOC treatment extended life expectancy by 1.81 years compared to SOC, generating 1.42 incremental QALYs. Total costs were CHF 172,086 for NP/AP + SOC versus CHF 151,908 for SOC, resulting in incremental costs of CHF 20,178/patient. ICERs were CHF 14,227/QALY gained and CHF 11,130/LY gained. At a WTP of CHF 100,000/QALY gained, NP/AP + SOC had a 96% probability of being cost-effective. LIMITATIONS: Long-term follow-up data (median 3.2 years) required extrapolation; real-world Swiss cost data were unavailable necessitating expert opinion; Belgian utility values were used as Swiss-specific data were unavailable. CONCLUSION: NP/AP + SOC is cost-effective for LA HNSCC in Switzerland, supporting clinical implementation.