Table 1. Key Model Inputs.
| Parameter | Expected value (range) | Distribution | Reference |
|---|---|---|---|
| Clinical input | |||
| Survival model for sorafenib | 5 | ||
| Log-normal model for PFSa | Log-mean = 1.9445, log-SD = 1.1894 | ||
| Log-logistic model for OSa | Shape = 1.5145, rate = 18.5865 | ||
| Survival model for atezolizumab plus bevacizumab | 5 | ||
| Royston-Parmar spline model for PFSa | Gamma0 = −2.9276, gamma1 = 3.9106, gamma2 = 1.0361, gamma3 = −0.8589 | ||
| Log-normal model for OSa | Log-mean = 2.5567, log-SD = 1.2314 | ||
| Royston-Parmar spline model for OS associated with sorafeniba | Gamma0 = −8.7209522, gamma1 = 2.4499163, gamma2 = 0.1511148 | 4 | |
| HR for PFS associated with atezolizumab plus bevacizumab vs sorafenib | 0.59 (0.47 to 0.76) | Log-normal: log-mean = −0.528, log-SD = 2.604 | 5 |
| HR for OS associated with atezolizumab plus bevacizumab vs sorafenib | 0.58 (0.42 to 0.79) | Log-normal: log-mean = −0.545, log-SD = 2.36 | 5 |
| Proportion receiving subsequent treatment | 5 | ||
| Sorafenib | 0.67 (0.50 to 0.84) | Beta: α = 5.3, β = 2.6 | |
| Atezolizumab plus bevacizumab | 0.35 (0.26 to 0.44) | Beta: α = 10.4, β = 19.3 | |
| Utility input | |||
| Utility of PFD | 0.76 (0.61 to 0.91) | Beta: α = 4.7, β = 1.5 | 10 |
| Utility of PD | 0.68 (0.54 to 0.82) | Beta: α = 29, β = 13.6 | 10 |
| Disutility due to AEs | |||
| Grade 1 and 2 | 0.01 (0.008 to 0.020) | Beta: α = 18, β = 1283.2 | 11 |
| Grade 3 and higher | 0.16 (0.110 to 0.204) | Beta: α = 36, β = 193 | 11 |
| Cost input | |||
| Atezolizumab per 1200 mgb | 9280 (4640 to 9280) | Fixed | 12, 13 |
| Bevacizumab per 100 mgb | 841 (420 to 841) | Fixed | 12, 13 |
| Sorafenib per 200 mgc | 174 (87 to 174) | Fixed | 12, 13 |
| Subsequent active treatment per patientd | 108 336 (81 252 to 135 420) | Gamma: α = 433 345, λ = 0.25 | 14 |
| Subsequent best supportive care per patientd | 37 084 (27 813 to 46 355) | Gamma: α = 148 337, λ = 0.25 | 14 |
| Follow-up and monitoring per month | |||
| Patients with PFDe | 787 (590 to 984) | Gamma: α = 3149, λ = 0.25 | 15 |
| Patients with PDe | 915 (686 to 1144) | Gamma: α = 3659, λ = 0.25 | 15 |
| Drug administration per unit | 298 (223 to 372) | Gamma: α = 1191, λ = 0.25 | 11 |
| Terminal care per patientd | 7894 (6315 to 9473) | Gamma: α = 77 390, λ = 0.102 | 14 |
Abbreviations: AE, adverse event; HR, hazard ratio; OS, overall survival; PD, progressed disease; PFD, progression-free disease; PFS, progression-free survival.
a
Only expected values are presented for these survival model parameters.
b
Treatment with atezolizumab plus bevacizumab continued until disease progression, unacceptable toxicity, or 2 years of follow-up.
c
Treatment with sorafenib continued until disease progression or unacceptable toxicity.
d
Overall total cost per patient regardless of treatment duration.
e
These costs were assumed to be continued until the health state transitioned.