Cost-Effectiveness of Pembrolizumab Regimens for the First-Line Treatment of Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma in Argentina.

INTRODUCTION: The phase III KEYNOTE-048 trial showed that the programmed death receptor 1 (PD-1) inhibitor pembrolizumab, in the combined positive score (CPS) ≥ 1 population and combined with platinum + 5-fluorouracil in the total population, improves survival over cetuximab + platinum + 5-fluorouracil in recurrent or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC). We evaluated the cost-effectiveness of pembrolizumab as monotherapy in the CPS ≥ 1 population or combined with platinum + 5-fluorouracil in the total population versus cetuximab + platinum + 5-fluorouracil from the social security perspective in Argentina. METHODS: A partitioned survival model projected costs and outcomes over 20 years with 3% annual discounting. Health state occupancy was modeled using KEYNOTE-048 Kaplan-Meier curves 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 (AR $74.00 = 1 USD). Time-on-treatment and EuroQol five-dimension scores were taken from KEYNOTE-048. Utilities were derived using an Argentina-specific algorithm. RESULTS: With pembrolizumab monotherapy, patients accrued 1.1040 additional life-years and 0.8768 additional quality-adjusted life-years (QALYs), for incremental cost-effectiveness ratios (ICERs) of AR $135,801/life-year and AR $170,985/QALY gained over cetuximab + platinum + 5-fluorouracil. Additional life-years and QALYs gained with pembrolizumab combination therapy versus cetuximab + platinum + 5-fluorouracil were 1.3296 and 1.0536, respectively (ICERs of AR $680,143/life-year and AR $858,306/QALY). Considering a threshold of AR $1,676,122/QALY gained, pembrolizumab monotherapy and combination therapy had an 88.0% and a 77.1% probability of being cost-effective, respectively. CONCLUSION: Pembrolizumab either as monotherapy or in combination with chemotherapy offers substantial survival gains for patients with R/M HNSCC at small additional costs, making it a cost-effective treatment versus cetuximab + platinum + 5-FU in Argentina.

Cost-Effectiveness of Pembrolizumab for the Adjuvant Treatment of Melanoma Patients with Lymph Node Involvement Who Have Undergone Complete Resection in Argentina.

INTRODUCTION: The KEYNOTE-054 trial demonstrated that adjuvant pembrolizumab improves recurrence-free survival in completely resected stage III melanoma versus watchful waiting (hazard ratio [HR] = 0.57; 98.4% confidence interval [CI], 0.43-0.74). We evaluated the cost-effectiveness of pembrolizumab in Argentina, where watchful waiting is still widely used among these patients despite the high risk of recurrence with surgery alone. METHODS: A four-health state model was used (recurrence-free, locoregional recurrence [LR], distant metastases [DM], death). Lifetime medical costs to payers (72.08 Argentine pesos [AR$] = 1.00 U.S. dollar [USD]) and outcomes (3% annual discount) were assessed, together with incremental cost-effectiveness ratios (ICERs). First and LR→DM recurrences were modeled using KEYNOTE-054 and real-world data, respectively. No benefits of adjuvant treatment were assumed post-progression. Pre-DM and post-DM mortality was based on KEYNOTE-054 and on a network meta-analysis of advanced treatments expected in each arm, respectively. Utilities were derived from KEYNOTE-054 Euro-QoL data using an Argentinian algorithm, and from the literature. Public ex-factory drug prices were used. RESULTS: Patients in the pembrolizumab and the watchful waiting arms accrued 8.78 and 5.83 quality-adjusted life-years (QALYs), 9.91 and 6.98 life-years, and costs of AR$12,698,595 (176,174 USD) and AR$11,967,717 (166,034 USD), respectively. The proportion of life-years accrued that were recurrence-free was 80.8% and 56.9% in the pembrolizumab and the watchful waiting arms, respectively. Pembrolizumab patients gained 2.94 life-years and 2.96 QALYs versus watchful waiting; the ICER per QALY was AR$247,094 (3428 USD). Recurrence rates and advanced melanoma treatments were the key drivers of the ICER. At a threshold of AR$1,445,325 (29,935 USD) per QALY, pembrolizumab had an 83.5% probability of being cost-effective versus watchful waiting. CONCLUSIONS: Adjuvant pembrolizumab after complete resection of melanoma with node involvement is highly cost-effective relative to watchful waiting in Argentina, across disease stage subgroups and BRAF mutational status. This strongly supports its coverage and reimbursement across the entire health system.