OBJECTIVES: Phase III KEYNOTE-048 trial showed that programmed death receptor 1 (PD-1) inhibitor pembrolizumab, in the combined positive score (CPS) ≥1 population and combined with platinum + 5-fluorouracil (5-FU) in the total population, improves overall survival (OS) over cetuximab + platinum + 5-fluorouracil in patients with recurrent or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC). This study evaluated the cost-effectiveness of pembrolizumab as combination therapy with platinum-based therapies (cisplatin or carboplatin) plus 5-FU in the CPS≥1 population versus cetuximab + platinum + 5-FU from a third payer perspective in Colombia.

METHODS: A three-state cohort-based partitioned survival model projected costs and outcomes over 40 years with 3% annual discounting. Health state occupancy was modeled using KEYNOTE-048 Kaplan–Meier curves for progression-free survival (PFS) and OS, until the final analysis data cutoff; followed by parametric extrapolations guided by statistical criteria. Costs for initial and subsequent treatments, disease and adverse events management, and terminal care were included using public drug and procedures lists prices (SISMED & ISS Tariff Manual, respectively). Time-on-treatment and EuroQol five-dimension scores were taken from KEYNOTE-048. Utilities were derived using an Argentina-specific algorithm which provides utility values based on Latin American population.

RESULTS: With pembrolizumab combination therapy, patients accrued 2.0512 additional life-years (LY) and 1.6230 additional quality-adjusted life-years (QALYs), for incremental cost-effectiveness ratios (ICERs) of COP $48,330,146/LY and COP $61,078,685/QALY gained over cetuximab + platinum + 5-FU and making a cost-effective option considering a willingness to pay threshold of COP $69,150,201. Scenario analysis versus platinum + cetuximab + paclitaxel showed additional QALYs gained with pembrolizumab combination therapy (1.2597), for an ICER of COP $21,418,177/QALY.

CONCLUSIONS: Pembrolizumab in combination with chemotherapy offers substantial survival and QALY gains for patients with R/M HNSCC with PD-L1 expression of CPS≥1 at small additional costs, making it a cost-effective treatment versus cetuximab + platinum + 5-FU in Colombia.