Cost-Effectiveness Analysis of Gefitinib Plus Chemotherapy versus Gefitinib Alone for Advanced Non-Small-Cell Lung Cancer with EGFR Mutations in China

Figures & data

Figure 1 The Markov model simulated three health states: PFS, PD and death.

Table 1 Weibull Parameters of Model Estimated for Progression-Free and Overall Survival Curves

Group		Parameter	Mean	SE	95% CI
					Low	Up
GCP	PFS	Scale (λ)	0.007645	0.002764	0.003763	0.015529
		Shape (γ)	1.442737	0.101340	1.257181	1.655568
	OS	Scale (λ)	0.001160	0.000705	0.000352	0.003819
		Shape (γ)	1.622184	0.154090	1.346621	1.954137
Gefitinib	PFS	Scale (λ)	0.019543	0.005265	0.011526	0.033136
		Shape (γ)	1.391394	0.083233	1.237460	1.564476
	OS	Scale (λ)	0.003684	0.001721	0.001475	0.009202
		Shape (γ)	1.403482	0.120164	1.186665	1.659914

Abbreviations: GCP, gefitinib combined with carboplatin and pemetrexed; PFS, progression-free survival; OS, overall survival; SE, standard error; 95% CI, 95% confidence interval.

Figure 2 (A) Kaplan–Meier curve of the progression-free survival from the NEJ009 study. (B) Simulate progression-free survival curve for the GCP group and the gefitinib group. (C) Kaplan–Meier curve of overall survival from the NEJ009 study. (D) Simulate overall survival curve for the GCP group and the gefitinib group.

Table 2 The Incidence and Expenditures of SAEs

Variables	GCP Group	Gefitinib Group	Expenditures of SAEs ($/per Event)
Leukopenia	21.2	0.6	104.18
Neutropenia	31.2	0.6	67.26
Anemia	21.2	2.3	40.86
Thrombocytopenia	17.1	0.0	527.45
Liver dysfunction	12.4	22.2	85.28
Diarrhea	4.1	1.2	3.25
Vomiting	2.4	0.6	142
Stomatitis	0.6	0.0	4.66
Rash	4.1	2.9	1.47
Fatigue	4.1	0.0	105.36

Abbreviations: GCP, gefitinib combined with carboplatin and pemetrexed; SAEs, serious adverse events.

Table 3 Costs, Utilities, and Discount Rates in the Model

Variables	Base Case	Range	Distribution
Costs ($)
Gefitinib (250mg)	23.13	18.5–27.76	Triangle
Pemetrexed (100 mg)	94.2	75.36–113.04	Triangle
Carboplatin (100 mg)	15.8	12.64–18.96	Triangle
Follow-up cost per cycle	178.57	142.86–214.28	Triangle
Cost of salvage therapy per cycle	1238.96	1486.75–991.17	Triangle
Terminal care	2583.37	2066.70–3100.04	Triangle
Cost of managing SAEs for GCP group per cycle^a	7.67	6.14–9.2	Triangle
Cost of managing SAEs for gefitinib group per cycle^a	0.33	0.4–0.26	Triangle
Utility value
PFS	0.804	0.643–0.965	Beta
PD	0.321	0.257–0.385	Beta
Body surface area (m^2)	1.72	1.38–2.06	Triangle
Discount rate (%)	3	0–8	Fixed

Note: ^aCosts of each SAE were calculated via multiplying the incidence of SAE by the expenditures of managing per SAE.

Abbreviations: GCP, gefitinib combined with carboplatin and pemetrexed; SAE, serious adverse event; PFS, progression-free survival; PD, progressive disease.

Table 4 The Cost and Outcome Results of the Cost-Effectiveness Analysis

Parameters	GCP Group	Gefitinib Group
Costs ($)
PFS state	25,452.68	14,078.91
PD state	34,118.67	38,413.85
Total Cost	59,571.34	52,492.75
Incremental costs ($)	7078.59	/
Effectiveness (QALYs)
PFS state	1.75	1.05
PD state	0.69	0.77
Total effectiveness	2.44	1.82
Incremental effectiveness (QALYs)	0.62	/
ICER ($/QALY)	11,499.98	/

Abbreviations: GCP, gefitinib combined with carboplatin and pemetrexed; PFS, progression-free survival; PD, progressive disease; QALY, quality-adjusted life years; ICER, incremental cost–effectiveness ratio.

Figure 3 Tornado diagram of one-way sensitivity analysis. It summarized the results of one-way sensitivity analysis, which listed influential parameters in descending order according to their effect on the ICER over the variation of each parameter value.

Abbreviations: GCP, gefitinib combined with carboplatin and pemetrexed; PFS, progression-free survival; PD, progressive disease; SAEs, serious adverse events.

Figure 4 A probabilistic scatter plot of the ICER between the GCP and gefitinib group. Each dot represents the ICER for 1 simulation. An ellipse means 95% confidence interval. Dots that are located below the ICER threshold represent cost-effective simulations. (A) A probabilistic scatter plot of under WTP=$10,499.57 (1 GDP). (B) A probabilistic scatter plot of under WTP=$31,498.70 (3 GDP).

Abbreviations: GCP, gefitinib combined with carboplatin and pemetrexed; GDP, gross domestic product; ICER, incremental cost–effectiveness ratio.

Figure 5 Cost–effectiveness acceptability curve.

Abbreviations: GCP, gefitinib combined with carboplatin and pemetrexed; WTP, willingness-to-pay; GDP, gross domestic product.