Table 1.
Model Parameters and Assumptions.
| Parameters | Baseline value | Ranges | Distribution | Ref |
|---|---|---|---|---|
| Survival | ||||
| Log-logistic survival model for AEP a | ||||
| OS | θ=0.003072, κ=2.297440 | – | – | (10) |
| PFS | θ=0.008895, κ=2.852489 | – | – | (10) |
| HR for AEP vs DEP b | ||||
| OS | 1.04 | 0.83–1.25 | Lognormal | (10, 12) |
| PFS | 1.01 | 0.81–1.21 | Lognormal | (10, 12) |
| Weibull survival model for EP c | ||||
| OS | λ=0.016073, γ=1.593409 | – | – | (10, 12) |
| PFS | λ=0.042826, γ=1.712046 | – | – | (10, 12) |
| Costs | ||||
| Atezolizumab price/mg | 7.83 | 5.87–9.78 | Gamma | (21) |
| Durvalumab price/mg | 7.60 | 5.70–9.50 | Gamma | (21) |
| Etoposide price/mg | 1.51 | 1.13–1.89 | Gamma | (21) |
| Carboplatin price/mg | 0.06 | 0.04–0.07 | Gamma | (21) |
| Topotecan price/mg | 12.75 | 9.56–15.94 | Gamma | (21) |
| Advent event (1st-line atezolizumab plus chemotherapy) | 4959.82 | 3719.87–6199.78 | Gamma | (22) |
| Advent event (1st-line durvalumab plus chemotherapy) | 4743.05 | 3557.29–5928.81 | Gamma | (22) |
| Advent event (1st-line chemotherapy) | 6100.94 | 4508.96–7514.93 | Gamma | (22) |
| Advent event (2nd-line topotecan) | 14487.33 | 10865.50–18109.16 | Gamma | (22) |
| Administration intravenous, first hour | 142.55 | 106.91–178.19 | Gamma | (23) |
| Administration intravenous, additional hour | 30.68 | 23.01–38.35 | Gamma | (23) |
| Monthly physician visit | 148.33 | 111.25–185.41 | Gamma | (23) |
| Three-monthly imaging | 122.71 | 92.03–153.39 | Gamma | (23) |
| Monthly supportive care | 637.00 | 477.75–796.25 | Gamma | (24) |
| Death associated costs | 9433.00 | 7074.75–11791.25 | Gamma | (24) |
| Utilities | ||||
| PFS | 0.673 | 0.538–0.808 | Beta | (15, 16) |
| PS | 0.473 | 0.378–0.568 | Beta | (15, 16) |
| Disutility for EP | 0.112 | 0.090–0.134 | Beta | (25) |
| Disutility for AEP | 0.090 | 0.072–0.108 | Beta | (25) |
| Disutility for DEP | 0.094 | 0.075–0.113 | Beta | (25) |
| Others | ||||
| Proportion of subsequent therapy in the atezolizumab plus chemotherapy group | 0.517 | 0.414–0.620 | Beta | (10) |
| Proportion of subsequent therapy in the durvalumab plus chemotherapy group | 0.420 | 0.336–0.504 | Beta | (12) |
| Proportion of subsequent therapy in the chemotherapy group | 0.516 | 0.413–0.619 | Beta | (10, 12) |
| Body surface area (meters2) | 1.80 | 1.35–2.25 | Gamma | (16) |
| Creatinine clearance rate(ml/min) | 70.00 | 52.50–87.50 | Gamma | (16) |
a
Theta (θ) and kappa (γ) represented two parameters of log-logistic distribution.
b
The OS HR and PFS HR for AEP vs DEP were generated using network meta-analysis.
c
Lambda (λ) and gamma (γ) represented two parameters of Weibull distribution.
AEP, atezolizumab combined with etoposide and platinum; DEP, durvalumab combined with etoposide and platinum; EP, etoposide plus platinum; OS, overall survival; PFS, progression-free survival; PS, progressed survival.