Cost-effectiveness of pembrolizumab for the first-line treatment of recurrent or metastatic head and neck squamous cell carcinoma in Colombia.

[BACKGROUND/AIMS] KEYNOTE-048 (KN-048), a phase III clinical trial was conducted in first-line patients with recurrent or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC). It demonstrated that pembrolizumab, when combined with platinum-based therapies (cisplatin or carboplatin) plus 5-Fluorouracil (5-FU) in the overall population, and in the combined positive score (CPS) ≥ 1 population, improves overall survival (OS) compared to the combination of cetuximab + platinum + 5-FU (EXTREME regime). The aim was to evaluate the cost-effectiveness of pembrolizumab as a combination therapy in the 1 L HNSCC CPS ≥ 1 sub-population compared to the EXTREME regime from a healthcare system perspective in Colombia.

[METHODS] We built a three-state partitioned survival model to project the costs and outcomes over 40 years assuming a 3% annual discount. We used data from KEYNOTE-048 to model fits for progression-free survival (PFS), OS and Time-on-treatment curves for 1 L. Parametric extrapolations were then employed for the second part of the fit. The time-point selection was based on a series of statistical criteria including the chow test and log-hazard functions as well as an examination of remaining event within the tail of the curves. The parametric curve fits were guided by a comparison of real-world data, AIC/BIC criteria as well as visual inspection. Cost data for both first-line and subsequent treatments were derived from national public drug and procedures lists, namely SISMED and ISS Tariff Manual. Utilities were derived from KEYNOTE-048 Euro-QoL five dimension, using an Argentina-specific algorithm.

[RESULTS] An additional 2.05 life-years (LY) and 1.62 quality-adjusted life-years (QALYs) were the result versus comparator. The incremental cost-effectiveness ratios (ICERs) were COP $48,330,146/LY gained and COP $61,078,685/QALY gained, which were lower than the 2023 Colombian willingness-to-pay (WTP) threshold (COP $69,150,201).

[CONCLUSIONS] Pembrolizumab combination therapy offers substantial survival and QALY gains for R/M HNSCC patients with an ICER lower than the Colombian willingness to pay making it a cost-effective treatment in Colombia.