Cost-effectiveness analysis of pembrolizumab versus chemotherapy as first-line treatment for mismatch-repair-deficient (dMMR) or microsatellite-instability-high (MSI-H) advanced or metastatic colorectal cancer from the perspective of the Chinese health-care system

Abstract

Background: Pembrolizumab is superior to chemotherapy as a first-line treatment for patients with mismatch-repair-deficient (dMMR) or microsatellite-instability-high (MSI-H) advanced or metastatic colorectal cancer (CRC), with a significant long-term survival benefit according to the KEYNOTE-177 trial. The current study aimed to determine whether pembrolizumab is a cost-effective treatment for patients with dMMR/MSI-H advanced or metastatic CRC in China. Methods: A partitioned survival model (PSM) was developed to simulate patients with dMMR/MSI-H advanced or metastatic CRC based on progression-free survival (PFS), progressive disease (PD) and death. The model was designed using a lifetime horizon, a 6-week cycle, and a 5% discount rate. The patients in the model had metastatic dMMR/MSI-H CRC and had not previously received treatment; these characteristics were similar to those of patients in KEYNOTE-177, a phase 3, open-label randomized clinical trial. The health outcomes and utilities were based on the KEYNOTE-177 trial and published data, respectively. Costs were calculated based on local charges (2022) and published literature. A treatment was deemed cost-effective in China if the incremental cost-effectiveness ratio (ICER) value was less than U.S.$38,142.56 per quality-adjusted life-year (QALY). The robustness of the results was assessed via one-way deterministic and probabilistic sensitivity analyses. Results: Baseline analysis revealed that pembrolizumab provided an additional 2.58 QALYs (3.00 life-year) at an incremental cost of U.S.$78,286.04, resulting in an ICER of U.S.$30,330.15 per QALY, which was below the willingness-to-pay threshold of U.S.$38,142.56 per QALY. When the patient assistance program (PAP) was considered, the ICER became U.S.$1,730.67 per QALY, manifesting absolute cost-effectiveness. The results of sensitivity analyses demonstrated that pembrolizumab was cost-effective in most cases. Conclusions: Pembrolizumab is a cost-effective first-line treatment for dMMR/MSI-H advanced or metastatic CRC patients in China, especially considering the PAP.