Cost-Effectiveness Analysis of Adjuvant Pembrolizumab Versus Standard-of-Care (SOC) Immunotherapies (High-Dose interferon Alfa 2-b or Ipilimumab) in High-Risk Resected Melanoma in United States (US)
Author(s)
Syeda Hina Zaidi, MS, Roselyn Salomey Amamoo, MPH, Ivo Abraham, PhD.
R Ken Coit College of Pharmacy, The University of Arizona, Tucson, AZ, USA.
R Ken Coit College of Pharmacy, The University of Arizona, Tucson, AZ, USA.
Presentation Documents
OBJECTIVES: The phase III S1404 trial comparing adjuvant pembrolizumab with SOC immunotherapies in high-risk resected melanoma patients showed improvement in median recurrence-free survival (RFS) for approximately 6 months but no difference in median overall survival (OS). We conducted a cost-effectiveness analysis (CEA) for the US to assess the economic and clinical value of pembrolizumab versus SOC.
METHODS: The study utilized S1404 trial data incorporating a partitioned-survival model (PSM) to simulate three health states: RFS, recurrence, and death. Costs (USD) and utility inputs were derived from published literature and S1404. Key model inputs include digitized survival curves for RFS and OS, drug costs based on treatment duration and unit prices, infusion costs, costs of adverse events, hazard ratios, and discount rates. Parametric survival functions were fitted to trial data for RFS and OS; Generalized F and log-normal were the best-fitting models (lowest AIC) for RFS and OS, respectively. The probability of state membership graph showed pembrolizumab improved survival and lowered death probabilities, especially in early to mid-treatment stages. Deterministic sensitivity analyses (DSA) assessed result robustness and key drivers of the incremental cost-effectiveness ratio (ICER). The analysis was conducted using INES, an open-access R-powered tool implementing three-state PSMs.
RESULTS: Pembrolizumab improved RFS with an incremental life year (ILY) of 0.361 and 0.102 for RFS and OS, respectively, while SOC performed better post-recurrence with ILY of 0.259. The negative ICER ( -2,418,886 USD) corresponds to an incremental QALYs of 0.093, with pembrolizumab providing 4.19 QALYs gained compared to 4.097 for SOC treatment arm. Tornado plot identified pembrolizumab and SOC costs, along with RFS utility, as key ICER drivers.
CONCLUSIONS: Pembrolizumab offers marginal QALY gains (0.093, about one month) and a negative ICER (-$2,418,886 USD), reflecting modest cost savings based on actual survival improvements. Further validation through probabilistic sensitivity analyses is needed.
METHODS: The study utilized S1404 trial data incorporating a partitioned-survival model (PSM) to simulate three health states: RFS, recurrence, and death. Costs (USD) and utility inputs were derived from published literature and S1404. Key model inputs include digitized survival curves for RFS and OS, drug costs based on treatment duration and unit prices, infusion costs, costs of adverse events, hazard ratios, and discount rates. Parametric survival functions were fitted to trial data for RFS and OS; Generalized F and log-normal were the best-fitting models (lowest AIC) for RFS and OS, respectively. The probability of state membership graph showed pembrolizumab improved survival and lowered death probabilities, especially in early to mid-treatment stages. Deterministic sensitivity analyses (DSA) assessed result robustness and key drivers of the incremental cost-effectiveness ratio (ICER). The analysis was conducted using INES, an open-access R-powered tool implementing three-state PSMs.
RESULTS: Pembrolizumab improved RFS with an incremental life year (ILY) of 0.361 and 0.102 for RFS and OS, respectively, while SOC performed better post-recurrence with ILY of 0.259. The negative ICER ( -2,418,886 USD) corresponds to an incremental QALYs of 0.093, with pembrolizumab providing 4.19 QALYs gained compared to 4.097 for SOC treatment arm. Tornado plot identified pembrolizumab and SOC costs, along with RFS utility, as key ICER drivers.
CONCLUSIONS: Pembrolizumab offers marginal QALY gains (0.093, about one month) and a negative ICER (-$2,418,886 USD), reflecting modest cost savings based on actual survival improvements. Further validation through probabilistic sensitivity analyses is needed.
Conference/Value in Health Info
2025-05, ISPOR 2025, Montréal, Quebec, CA
Value in Health, Volume 28, Issue S1
Code
EE516
Topic
Economic Evaluation
Disease
SDC: Oncology