TABLE 1.
Input parameters of the model.
| Parameter | Baseline value | Lower limit | Upper limit | Distribution | Source |
|---|---|---|---|---|---|
| Survival model of T-DM1 | |||||
| Lognormal PFS survival model | meanlog = 2.1852 | ND | ND | ND | Model fitting |
| sdlog = 1.1752 | |||||
| Generalised gamma OS survival model | mu = 3.6876 | ND | ND | ND | Model fitting |
| sigma = 0.8951 | |||||
| Q = 0.3992 | |||||
| HR for OS (PC vs. T-DM1) | 1.00 | 0.66 | 1.52 | Lognormal | Network meta-analysis |
| HR for PFS (PC vs. T-DM1) | 0.60 | 0.40 | 0.89 | Lognormal | Network meta-analysis |
| HR for OS (T-DXd vs. T-DM1) | 0.64 | 0.47 | 0.87 | Lognormal | Network meta-analysis |
| HR for PFS (T-DXd vs. T-DM1) | 0.33 | 0.26 | 0.43 | Lognormal | Network meta-analysis |
| Drug cost (per cycle) | |||||
| T-DM1 | 1,084.54 | 867.64 | 1,301.45 | Gamma | Chinese drug price of drug centralized bid procurement (2023) |
| Pyrotinib | 1,051.18 | 840.94 | 1,261.41 | Gamma | Chinese drug price of drug centralized bid procurement (2023) |
| Capecitabine | 153.77 | 123.02 | 184.52 | Gamma | Chinese drug price of drug centralized bid procurement (2023) |
| T-DXd | 3,727.91 | 2982.33 | 4,473.49 | Gamma | Chinese drug price of drug centralized bid procurement (2023) |
| Progressive disease therapy | 2232.41 | 1785.93 | 2678.89 | Gamma | Chinese drug price of drug centralized bid procurement (2023) |
| T-DM1 | 97.73 | 78.18 | 117.27 | Gamma | Expert interviews |
| PC | 103.37 | 82.69 | 124.04 | Gamma | Expert interviews |
| T-DXd | 175.66 | 140.53 | 210.79 | Gamma | Expert interviews |
| Healthcare resource utilization cost | |||||
| PFS status (first cycle) | 649.25 | 519.40 | 779.10 | Gamma | Expert interviews |
| PFS status (follow-up cycle) | 54.09 | 43.27 | 64.90 | Gamma | Expert interviews |
| PD status | 68.03 | 54.42 | 81.63 | Gamma | Expert interviews |
| Concomitant therapy cost | 21.32 | 17.05 | 25.58 | Gamma | Expert interviews |
| End-of-life care | 97.22 | 77.78 | 116.67 | Gamma | Expert interviews |
| AEs cost | |||||
| Diarrhea | 16.30 | 13.04 | 19.57 | Gamma | Expert interviews |
| Vomiting | 16.30 | 13.04 | 19.57 | Gamma | Expert interviews |
| Neutropenia | 123.00 | 98.40 | 147.60 | Gamma | Expert interviews |
| Fatigue | 22.91 | 18.33 | 27.49 | Gamma | Expert interviews |
| Nausea | 16.30 | 13.04 | 19.57 | Gamma | Expert interviews |
| Anemia | 79.10 | 63.28 | 94.92 | Gamma | Expert interviews |
| Alanine aminotransferase increased | 60.34 | 48.27 | 72.41 | Gamma | Expert interviews |
| Aspartate aminotransferase increased | 60.34 | 48.27 | 72.41 | Gamma | Expert interviews |
| Health utility | |||||
| PFS state | 0.850 | 0.680 | 1.000 | Beta | Wu and Ma (2020) |
| PD state | 0.520 | 0.420 | 0.620 | Beta | Wu and Ma (2020) |
Abbreviations: OS, overall survival; PFS, progression-free survival; PD, progressive disease; HRs, hazard ratios; AEs, adverse events; T-DM1, trastuzumab emtansine; T-DXd, trastuzumab deruxtecan; ND, not determined.