Presentation (CTI)

OBJECTIVES: Patients with resectable stage III-IV melanoma have a high risk of recurrence. The S1801 trial showed that neoadjuvant plus adjuvant pembrolizumab improved event-free survival when compared to adjuvant therapy alone. The economic value of this approach remains uncertain. This study aimed to assess the cost-effectiveness of neoadjuvant plus adjuvant pembrolizumab versus adjuvant-only pembrolizumab from the U.S. third-party payer perspective.
METHODS: A six-state Markov model was designed to simulate clinical and economic outcomes in patients with stage IIIB to IVC melanoma amenable to surgical resection. Neoadjuvant-adjuvant group received three doses of pembrolizumab (200 mg intravenously every 3 weeks) before surgery, followed by 15 doses after surgery. Adjuvant-only group received 18 doses of pembrolizumab (200 mg every 3 weeks) after surgery. Health states included event-free, local recurrence, locoregional metastasis, distant metastasis, post-progression, and death. Clinical inputs were based on published clinical findings. The model time horizon was 40 years, with weekly cycles to estimate long-term outcomes including direct medical costs and quality-adjusted life years (QALYs). Costs and utilities were derived from published literature. A 3% annual discount rate was applied. One-way and probabilistic sensitivity analyses were conducted to evaluate the robustness of base-case results.
RESULTS: In base-case analysis, the neoadjuvant plus adjuvant strategy gained incremental 2.95 QALYs with cost saving of USD 53,865 when compared to the adjuvant-only strategy. At a willingness-to-pay threshold of USD 50,000 per QALY, no influential factor with threshold value was identified by one-way sensitivity analysis. Probabilistic sensitivity analysis showed the neoadjuvant plus adjuvant strategy was cost-effective in a 100% of 10,000 Monte Carlo simulations across WTP thresholds ranging from USD 0 to 100,000 per QALY.
CONCLUSIONS: Neoadjuvant plus adjuvant pembrolizumab is a cost-effective strategy compared to adjuvant-only pembrolizumab for patients with resectable stage IIIB-IVC melanoma who undergo surgery, from a U.S. third-party payer perspective.