Indirect cost-effectiveness analyses of abatacept and rituximab in patients with moderate-to-severe rheumatoid arthritis in the United States

Figures & data

Figure 1. Designs of the ATTAIN and REFLEX trials.

Table 1. Characteristics of patients at baseline in the ATTAIN and REFLEX trials*.

Characteristic	ATTAIN		REFLEX
	Abatacept/MTX*	MTX^†	Rituximab/MTX	MTX
N	258	133	308	209
Age (years)	53.4±12.4	52.7±11.3	52.2±12.2	52.8±12.6
Female	77	80	81	81
Disease duration (years)	12.2±8.5	11.4±8.9	12.1±8.3	11.7±7.7
Tender joints	31.2±13.0	32.8±13.4	33.9±15.1	33.0±15.6
Swollen joints	22.3±10.2	22.0±10.0	23.4±11.8	22.9±12.7
HAQ score	1.8±0.6	1.8±0.6	1.9± 0.6	1.9±0.5

HAQ, Health Assessment Questionnaire.

*Plus-minus values are means ± standard deviation.

^†Most (> 75%) of oral DMARD use in the ATTAIN trial was MTX.

Table 2. Estimates of clinical parameters used in the cost-utility model.

	Value
	Abatacept	Rituximab
Pre-treatment HAQ-DI (% of patients, by HAQ-DI interval)
0.00 – < 0.25	1.0	1.0
0.25 – < 0.50	0.5	0.5
0.50 – < 0.75	1.8	1.8
0.75 – < 1.00	4.4	4.4
1.00 – < 1.25	6.9	6.9
1.25 – < 1.50	8.2	8.2
1.50 – < 1.75	14.7	14.7
1.75 – < 2.00	14.7	14.7
2.00 – < 2.25	17.0	17.0
2.25 – < 2.50	15.4	15.4
2.50 – < 2.75	4.6	4.6
2.75–3.00	10.8	10.8
HAQ-DI change vs. pre-treatment (mean ± SD*)
6 months	–25±33.7%	–22±31.6%
Annual HAQ-DI progression
Biologic	0.015	0.015
Oral DMARDs	0.065	0.065
Threshold for clinically meaningful improvement in HAQ-DI at 6 months	–0.5	–0.5
Annual discontinuation for reasons other than lack of efficacy (%) (year 1)	8.10	8.10
Annual discontinuation for all reasons (%) (subsequent years)	8.10	8.10
Mortality, odds-ratio for each 1-point increase in HAQ-DI	1.80	1.80
Health-state utility^† (mean ± SD*), by HAQ-DI interval
0.00 – < 0.25	0.86±0.16	0.86±0.16
0.25 – < 0.50	0.80±0.13	0.80±0.13
0.50 – < 0.75	0.76±0.14	0.76±0.14
0.75 – < 1.00	0.71±0.15	0.71±0.15
1.00 – < 1.25	0.66±0.15	0.66±0.15
1.25 – < 1.50	0.59±0.18	0.59±0.18
1.50 – < 1.75	0.51±0.19	0.51±0.19
1.75 – < 2.00	0.43±0.21	0.43±0.21
2.00 – < 2.25	0.33±0.24	0.33±0.24
2.25 – < 2.50	0.23±0.25	0.23±0.25
2.50 – < 2.75	0.12±0.27	0.12±0.27
2.75 – 3.00	0.03±0.33	0.03±0.33

*Standard deviation; ^†Derived from EuroQoL values.

Table 3. Outcomes and costs per patient with abatacept and rituximab versus methotrexate.

	Abatacept/MTX	Rituximab/MTX
QALYs gained (95% CI)	1.25 (1.13–1.38)	1.10 (0.97–1.28)
Incremental cost (95% CI)	$58,989 ($54,254–66,070)	$60,380 ($54,416–67,293)
Incremental CU ratio	$47,191($44,810–49,920)	$54,891($52,274–58,073)

CE, cost utility.

Figure 2. Cost-utility acceptability curves.

Table 4. Sensitivity analyses on key model assumptions and parameter estimates.

Scenario	Change in assumption or parameter estimate	Incremental $/QALY (95% CI)
		Abatacept/MTX	Rituximab/MTX
Reference case	No change	47,191 (44,810, 49,920)	54,891 (52,274, 58,073)
1	No therapy discontinuation for lack of efficacy or other reasons	63,297 (57,036,68,110)	75,310 (68,180, 80,299)
	Mortality odds ratio for each one-point increase in HAQ-DI
2	1.0	46,300 (42,393,49,603)	57,196 (53,739,62,993)
3	1.5	46,613 (44,779,50,206)	54,570 (52,515,57,690)
4	2.0	46,751 (44,401,49,420)	55,935 (52,421,61,473)
	Annual increase in HAQ-DI for abatacept and rituximab
5	0.031	50,396 (46,719,53,637)	58,650 (53,638,67,346)
	Threshold for clinically meaningful improvement in HAQ-DI at 6 months
6	–0.25	51,373 (47,528,54,524)	62,430 (58,330,70,054)
7	–0.75	43,949 (41,802,45,895)	52,693 (49,081,58,358)
	Patient gender and age
	Women
8	18–34 years	45,238 (42,037,47,510)	53,862 (49,774,58,299)
9	35–44 years	45,056 (42,811,46,806)	54,366 (50,014,59,923)
10	45–54 years	46,973 (44,384,49,808)	54,680 (50,631,59,178)
11	55–64 years	47,191 (44,810, 42,920)	54,891 (52,274, 58,073)
12	65–74 years	47,326 (44,531,51,472)	56,438 (52,205,64,553)
13	75–84 years	50,144 (45,572,53,402)	58,883 (52,258,71,309)
14	>85 years	57,034 (50,981,62,772)	65,927 (57,569,77,100)
	Men
15	18–34 years	44,751 (42,615,47,988)	53,753 (47,939,57,296)
16	35–44 years	44,309 (42,527,46,245)	53,842 (50,686,56,036)
17	45–54 years	43,729 (41,707,45,478)	53,283 (49,878,56,662)
18	55–64 years	44,386 (42,401,46,189)	54,994 (52,364,58,494)
19	65–74 years	44,300 (42,070,47,151)	53,417 (51,654,55,666)
20	75–84 years	46,982 (44,738,48,395)	59,487 (55,858,62,412)
21	>85 years	58,700 (55,526,61,777)	70,234 (67,266,74,582)