TABLE 1.
Base-case model parameter.
| Parameter | Baseline value | Range | Distribution | Reference |
|---|---|---|---|---|
| Log-logistic OS survival model of switch maintenance group | shape = 2.309, scale = 13.051 | — | — | Randon et al. (2024) |
| Log-logistic OS survival model of control group | shape = 1.891, scale = 9.593 | — | — | Randon et al. (2024) |
| Log-logistic PFS survival model of switch maintenance group | shape = 2.061, scale = 6.767 | — | — | Randon et al. (2024) |
| Log-logistic PFS survival model of control group | shape = 1.697, scale = 3.579 | — | — | Randon et al. (2024) |
| Log-logistic OS survival model of switch maintenance group in PD-L1-CPS≥5 patients | shape = 2.386, scale = 15.518 | — | — | Randon et al. (2024) |
| Log-normal OS survival model of control group in PD-L1-CPS≥5 patients | meanlog = 2.376, sdlog = 0.805 | — | — | Randon et al. (2024) |
| Log-normal PFS survival model of switch maintenance group in PD-L1-CPS≥5 patients | meanlog = 2.0989, sdlog = 0.7146 | — | — | Randon et al. (2024) |
| Log-normal PFS survival model of control group in PD-L1-CPS≥5 patients | meanlog = 1.802, sdlog = 0.856 | — | — | Randon et al. (2024) |
| Cost from the chinese perspective | ||||
| Enhanced CT per unit | 23.693 | 10.659–106.647 | Gamma | Qiu et al. (2023) |
| Blood biochemistry per unit | 63.814 | 33.253–93.564 | Gamma | Qiu et al. (2023) |
| Blood routine per unit | 1.930 | 1.425–3.622 | Gamma | Qiu et al. (2023) |
| Urine routine per unit | 0.594 | 0.287–2.553 | Gamma | Qiu et al. (2023) |
| Injection administration | 0.802 | 0.158–0.643 | Gamma | Qiu et al. (2023) |
| Intravenous injection | 0.713 | 0.356–1.564 | Gamma | Qiu et al. (2023) |
| Cost of terminal care | 1,506.51 | 1,205.21–1,807.81 | Gamma | Qiu et al. (2023) |
| Cost of BSC per cycle | 267.78 | 214.22–321.34 | Gamma | Zhou et al. (2025) |
| Ramucirumab/mg | 5.23 | 4.186–6.279 | Gamma | Shanghai sunshine procurement all. (2025) |
| Paclitaxel/mg | 0.280 | 0.224–0.335 | Gamma | Shanghai sunshine procurement all. (2025) |
| Ondansetron/mg | 0.360 | 0.288–0.433 | Gamma | Shanghai sunshine procurement all. (2025) |
| Dexamethasone/mg | 0.018 | 0.0148–0.0221 | Gamma | Shanghai sunshine procurement all. (2025) |
| Diphenhydramine/mg | 0.103 | 0.0823–0.123 | Gamma | Shanghai sunshine procurement all. (2025) |
| Capecitabine/mg | 0.000653 | 0.000522–0.000783 | Gamma | Shanghai sunshine procurement all. (2025) |
| Calcium folinate/mg | 0.0355 | 0.0284–0.0426 | Gamma | Shanghai sunshine procurement all. (2025) |
| Oxaliplatin/mg | 0.881 | 0.705–1.058 | Gamma | Shanghai sunshine procurement all. (2025) |
| 5-Fluorouracil/mg | 0.0183 | 0.0146–0.0220 | Gamma | Shanghai sunshine procurement all. (2025) |
| Irinotecan/mg | 0.0955 | 0.0764–0.115 | Gamma | Shanghai sunshine procurement all. (2025) |
| Cost from the US perspective | ||||
| Enhanced CT per unit | 530.79 | 424.63–636.95 | Gamma | Centers for Medicare and Medicaid Services. (2025) |
| Blood biochemistry per unit | 10.56 | 8.45–12.67 | Gamma | Centers for Medicare and Medicaid Services. (2025) |
| Blood routine per unit | 7.77 | 6.22–9.32 | Gamma | Centers for Medicare and Medicaid Services. (2025) |
| Urine routine per unit | 3.17 | 2.54–3.80 | Gamma | Centers for Medicare and Medicaid Services. (2025) |
| Injection administration | 13.91 | 11.13–16.69 | Gamma | Centers for Medicare and Medicaid Services. (2025) |
| Intravenous injection | 223.30 | 178.64–267.96 | Gamma | Centers for Medicare and Medicaid Services. (2025) |
| Cost of terminal care | 19,247.03 | 15,397.62–23,096.44 | Gamma | Zhu et al. (2023) |
| Cost of BSC per cycle | 2,262.59 | 1,810.07–2,715.11 | Gamma | Zhu et al. (2023) |
| Ramucirumab/mg | 15 | 12–18 | Gamma | IBM Micromedex IBM Corporation. (2025) |
| Paclitaxel/mg | 0.2882 | 0.23056–0.34584 | Gamma | IBM Micromedex IBM Corporation. (2025) |
| Ondansetron/mg | 0.1056 | 0.08448–0.12672 | Gamma | IBM Micromedex IBM Corporation. (2025) |
| Dexamethasone/mg | 0.02255 | 0.01804–0.02706 | Gamma | IBM Micromedex IBM Corporation. (2025) |
| Diphenhydramine/mg | 0.0602 | 0.04816–0.07224 | Gamma | IBM Micromedex IBM Corporation. (2025) |
| Capecitabine/mg | 0.002 | 0.0016–0.0024 | Gamma | IBM Micromedex IBM Corporation. (2025) |
| Calcium folinate/mg | 0.07026 | 0.056208–0.084312 | Gamma | IBM Micromedex IBM Corporation. (2025) |
| Oxaliplatin/mg | 0.6 | 0.48–0.72 | Gamma | IBM Micromedex IBM Corporation. (2025) |
| 5-Fluorouracil/mg | 0.01027 | 0.008216–0.012324 | Gamma | IBM Micromedex IBM Corporation. (2025) |
| Irinotecan/mg | 0.3 | 0.24–0.36 | Gamma | IBM Micromedex IBM Corporation. (2025) |
| AEs management costs from Chinese perspective | ||||
| Neutropenia | 136.792 | 109.418–164.147 | Gamma | Qiu et al. (2023) |
| Peripheral neuropathy | 1,097.008 | 8,77.607–1,316.410 | Gamma | Pike et al. (2012) |
| Hypertension | 17.824 | 14.261–21.387 | Gamma | Qiu et al. (2023) |
| AEs management costs from US perspective | ||||
| Neutropenia | 18,360.82 | 14,688.66–22,032.98 | Gamma | Stenehjem et al. (2023) |
| Peripheral neuropathy | 14,184.2 | 11,347.36–17,021.04 | Gamma | Stenehjem et al. (2023) |
| Hypertension | 19,272.01 | 15,417.61–23,126.41 | Gamma | Zhang et al. (2021) |
| Utility | ||||
| PFS | 0.797 | 0.64–0.96 | Beta | Tsuchiya et al. (2002) |
| PD | 0.577 | 0.46–0.69 | Beta | Holden et al. (2011) |
| Disutility | ||||
| Neutropenia | 0.2 | 0.16–0.24 | Beta | Nafees et al. (2017) |
| Peripheral neuropathy | 0.16 | 0.128–0.192 | Beta | Swinburn et al. (2015) |
| Hypertension | 0.04 | 0.032–0.048 | Beta | Nafees et al. (2017) |
| Risk of serious AEs in switch maintenance group | ||||
| Neutropenia (%) | 26.24 | 20.99–31.49 | Beta | Randon et al. (2024) |
| Peripheral neuropathy (%) | 6 | 4.80–7.20 | Beta | Randon et al. (2024) |
| Hypertension (%) | 6 | 4.80–7.20 | Beta | Randon et al. (2024) |
| Risk of serious AEs in control group | ||||
| Neutropenia (%) | 9.63 | 7.70–11.56 | Beta | Randon et al. (2024) |
| Peripheral neuropathy (%) | 7 | 5.60–8.40 | Beta | Randon et al. (2024) |
| Others | ||||
| Weight of Chinese patients (kg) | 69 | 55.2–82.88 | Gamma | Central People’s Government of the People’s Republic of China. (2021) |
| Weight of US patients (kg) | 75 | 60–90 | Gamma | Luo et al. (2024) |
| BSA of Chinese patients (m2) | 1.74 | 1.392–2.088 | Gamma | Central People’s Government of the People’s Republic of China (2021) |
| BSA of US patients (m2) | 1.8 | 1.44–2.16 | Gamma | Li et al. (2021) |
| Discount rate in China (%) | 5 | 0–8 | Fixed | Liu et al. (2020) |
| Discount rate in US (%) | 3 | 0–8 | Fixed | Sanders et al. (2016) |
Abbreviations: OS, overall survival; PFS, progression-free survival; CT, computed tomography; AE, adverse event; PD, progressed disease; BSC, best supportive care; US, united states; PD-L1, programmed cell death ligand 1; CPS, combined positive score.