A projected cost-utility analysis of avacopan for the treatment of antineutrophil cytoplasmic antibody-associated vasculitis in Spain

Figures & data

Table 1. Baseline patient demographic and clinical characteristics. Source: Jayne et al. 2021 [15].

Characteristics	Avacopan (n = 166)	Prednisone (n = 164)
Age, years	61.2 ± 14.6	60.5 ± 14.5
Female, n (%)	68 (41.0)	76 (46.3)
Vasculitis disease status, n (%)
Newly diagnosed	115 (69.3)	114 (69.5)
Relapsed	51 (30.7)	50 (30.5)
Type of vasculitis, n (%)
GPA	91 (54.8)	90 (54.9)
MPA	75 (45.2)	74 (45.1)
Immunosuppressant inductiontreatment, n (%)
RTX	107 (64.5)	107 (65.2)
CYC	59 (35.5)	57 (34.8)
Use of any GC during screeningperiod, n (%)	125 (75.3)	135 (82.3)
Renal involvement*, n (%)	134 (80.7)	134 (81.7)

*Organ involvement was based on the Birmingham Vasculitis Activity Score.

CYC: cyclophosphamide; GC: glucocorticoids; GPA: granulomatosis with polyangiitis; MPA: microscopic polyangiitis; RTX: rituximab.

Figure 1. Markov model for AAV.

The cycles represent different health states that are mutually exclusive, and the square represent health events.

ESRD: end-stage renal disease; Ind: induction.

Note: Active disease represents the starting health state.

Table 2. Costs and utilities included.

Parameter	Mean (SE)	Distribution	Source
Administration cost of intravenous treatments	€ 237.30 (12.1*)	Gamma	[27]
AAV management
Blood test	€ 6.35 (0.32*)	Gamma	[27]
Liver function test	€ 21.29 (1.09*)	Gamma	[27]
X-ray	€ 44.06 (2.25*)	Gamma	[27]
CT scan	€ 182.24 (9.30*)	Gamma	[27]
Outpatient visit	€ 91.72 (4.68*)	Gamma	[27]
Monitoring and follow-up visit cost per health state (per cycle)
Active disease
CYC-based	€ 269.79 (-)	-	Calculated
Non-CYC based	€ 246.52 (-)	-	Calculated
Remission	€ 86.90 (-)	-	Calculated
Refractory disease	€ 149.99 (-)	-	Calculated
ESRD	€ 269.79 (-)	-	Assumption (equal to active disease)
ESRD management (annual)
Dialysis (maintenance)	€ 55,129.98 (2,813*)	Gamma	[31]
Renal transplant (first year)	€ 57,307.52 (2,924*)	Gamma	[28]
Renal transplant (maintenance)	€ 7,874.87 (402*)	Gamma	[28]
Hospitalization costs (per cycle)
AAV hospitalization	€ 3,254.08 (-)	-	[26]
Avacopan arm	€ 177.78 (-)	-	Calculated
GC arm	€ 363.70 (-)	-	Calculated
Utilities
Active disease
Avacopan arm	0.780 (0.02)	Beta	[15]
GC arm	0.779 (0.02)	Beta	[15]
Remission
Avacopan arm	0.849 (0.01)	Beta	[15]
GC arm	0.834 (0.01)	Beta	[15]
Relapse
Avacopan arm	0.806 (0.05)	Beta	[15]
GC arm	0.740 (0.06)	Beta	[15]
ESRD
Peritoneal Dialysis	0.530 (0.03*)	Beta	[37]
Hemodialysis	0.443 (0.02*)	Beta	[37]
Transplant	0.712 (0.04*)	Beta	[37]

The number of 28-day cycles for each treatment considered in the analysis was as follows: avacopan: 13 cycles; GC: 5 cycles (with gradual dose reduction from 60 mg to 0 mg); RTX: 1 cycle; CYC: 4 cycles; AZA: from the fourth cycle onwards as a maintenance therapy.

^*±10% was considered for unknown 95% confidence intervals.

AAV: antineutrophil cytoplasmic antibody-associated vasculitis; AZA: azathioprine; CT: computed tomography; CYC: cyclophosphamide; ESRD: end-stage renal disease; GC: glucocorticoids; RTX: rituximab; SE: standard error.

Table 3. Base case results: avacopan vs. GC arm (€ 2022).

Base-case analysis	Avacopan arm	GC arm	Incremental
Total costs (/patient)	€ 267,671	€ 251,662	€ 16,009
Acquisition of drugs (combined treatment)	€ 48,766	€ 15,351	€ 33,415
AAV management and hospitalizations	€ 10,900	€ 11,513	- € 613
ESRD management	€ 208,004	€ 224,798	- €16,794
Health outcomes
QALYs	6.52	6.17	0.35
LYG	9.72	9.43	0.28
ICERs
Cost per QALY gained	€ 45,638/QALY
Cost per LYG	€ 56,214/LYG

AAV: antineutrophil cytoplasmic antibody-associated vasculitis; ESRD: end-stage renal disease; GC: glucocorticoids; ICER: incremental cost-effectiveness ratio; LYG: life year gained; QALY: quality-adjusted life year.

Figure 2. Tornado diagram: avacopan vs. GC arm.

AAV: antineutrophil cytoplasmic antibody-associated vasculitis; AVA: avacopan; CYC: cyclophosphamide; eGFR: estimated glomerular filtration rate; GC: glucocorticoids; ICUR: incremental cost-utility ratio; ITT: intention to treat; RTX: rituximab.

Figure 3. Cost-effectiveness plane: avacopan vs. GC arm.

AVA: avacopan; CYC: cyclophosphamide; ICUR: Incremental cost-utility ratio; QALY: quality-adjusted life years; RTX: rituximab; WTP: willingness-to-pay.

Note: A WTP threshold of €60,000 per QALY gained was assumed.

Figure 4. Cost-effectiveness acceptability curve: avacopan vs. GC arm.

AVA: avacopan; CYC: cyclophosphamide; GC: glucocorticoids; RTX: rituximab.

Table 4. Scenario analysis: progression to ESRD (€ 2022).

Reference	ESRD (%)	Follow-up (years)	ESRD at 6 months (%)	ESRD at 7.1 years (%)	ICUR (€/QALY)
Base case: Robson et al., 2015	-	-	6.4%	13.9%	€ 45,638
Scenario 1 : Solans-Laqué et al., 2017*	16.8%	6.8	1.2%	17.5%	€ 62,055
Scenario 2: Villacorta et al., 2020	32.7%	3.4	5.1%	22.3%	€ 52,649
Scenario 3: Marco et al., 2018	35.1%	3.6	7.7%	49.1%	€ 62,538

*Considering GPA/MPA patients requiring dialysis.

Note: As data at 6 months and 7.1 years were not available in the studies included in the scenario analysis, extrapolations were made from the renal survival and dialysis data.

ESRD: end-stage renal disease; ICUR: incremental cost-utility ratio; QALY: quality-adjusted life year.

Jayne DRW, Merkel PA, Schall TJ, et al. Avacopan for the treatment of ANCA-Associated vasculitis. N Engl J Med. 2021;384(7):599–609. doi: 10.1056/NEJMoa2023386

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