Cost-Effectiveness of Pembrolizumab as an Adjuvant Treatment in Colombia for Melanoma Patients with Lymph Node Involvement After Complete Resection.

INTRODUCTION: The KEYNOTE-054 trial found that adjuvant treatment with pembrolizumab improved recurrence-free survival versus placebo in completely resected high-risk stage III melanoma patients. We assessed the cost-effectiveness of adjuvant pembrolizumab in Colombia compared with watchful waiting, a widely used strategy despite the high risk of recurrence with surgery alone. METHODS: A four-health state [recurrence-free (RF), locoregional recurrence (LR), distant metastases (DM), and death) Markov model was developed to assess the lifetime medical costs and outcomes (3% annual discount), along with cost-effectiveness ratios (ICERs). The transitions from the RF and LR states were modeled using KEYNOTE-054 data, and those from the DM state were modeled using data from the KEYNOTE-006 trial and a network meta-analysis of advanced treatments received after adjuvant pembrolizumab and watchful waiting. The health state utilities were derived from KEYNOTE-054 Euro-QoL data and literature. Costs are expressed in 2021 Colombian pesos (COP). RESULTS: Over a 46-year time horizon, patients on adjuvant pembrolizumab and watchful waiting were estimated to gain 9.69 and 7.56 quality-adjusted life-years (QALYs), 10.83 and 8.65 life-years (LYs), and incur costs of COP 663,595,726 and COP 563,237,206, respectively. The proportion of LYs spent in RF state was 84.63% for pembrolizumab and 72.13% for watchful waiting, yielding lower subsequent treatment, disease management, and terminal care costs for pembrolizumab. Adjuvant pembrolizumab improved survival by 2.18 LYs and 2.13 QALYs versus watchful waiting. The ICER per QALY was COP 47,081,917, primarily driven by recurrence rates and advanced melanoma treatments. The deterministic sensitivity analysis results were robust and consistent across various reasonable inputs and alternative scenarios. At a willingness-to-pay threshold of COP 69,150,201 per QALY, the probability of pembrolizumab being cost-effective was 65.70%. CONCLUSION: Pembrolizumab is cost-effective as an adjuvant treatment compared to watchful waiting among patients with high-risk stage III melanoma after complete resection in Colombia.

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.