Comparative analysis of US real-world dosing patterns and direct infusion-related costs for matched cohorts of rheumatoid arthritis patients treated with infliximab or intravenous golimumab

Figures & data

Figure 1 Subject selection.

Note: ^aIndex date is the first GLM-IV or IFX claim after January 1, 2014. ^bPatients may not have had their index medication within 12 months pre-index; however, they may have received the non-index drug during the pre-index period. In addition, patients could have no claims for a second non-study biologic on the index date.
Abbreviations: GLM-IV, golimumab intravenous; IFX, infliximab; RA, rheumatoid arthritis.

Table 1 Demographic characteristics of patients prior to matching

	GLM-IV N=647		IFX N=881		P-value
Age, years (mean, SD)	57.3	12.8	55.7	12.3	0.014
Age group (N, %)					0.269
18–34	24	3.7%	41	4.7%
35–44	72	11.1%	113	12.8%
45–54	174	26.9%	221	25.1%
55–64	216	33.4%	319	36.2%
65+	161	24.9%	187	21.2%
Sex (%, N)					0.017
Male	116	17.9%	202	22.9%
Female	531	82.1%	679	77.1%
Payer (N, %)					0.167
Commercial	475	73.4%	674	76.5%
Medicare	172	26.6%	207	23.5%
Length of follow-up, days (mean, SD)	614	161	627	163	0.122
Total all-cause pre-index health care costs, $ (mean, SD)	$44,255	$76,351	$34,027	$37,370	<0.001

Abbreviations: GLM-IV, golimumab intravenous; IFX, infliximab.

Table 2 Clinical characteristics of patients prior to matching

	GLM-IV N=647		IFX N=881		P-value
RA and comorbidity indices (mean, SD)
CIRAS	5.81	1.71	5.95	1.89	0.118
DCIa	0.76	1.18	0.71	1.23	0.398
Number of unique diagnosesb	21	11.18	20	11.33	0.406
Number of unique prescription drugs	18	10.50	18	10.62	0.740
Specific comorbid conditions (N, %)
Essential hypertension	296	45.7%	373	42.3%	0.184
Disorders of lipoid metabolism	221	34.2%	285	32.3%	0.458
Respiratory symptoms	204	31.5%	254	28.8%	0.255
Diabetes	120	18.5%	141	16.0%	0.192
Depression	74	11.4%	107	12.1%	0.672
Osteoporosis	74	11.4%	96	10.9%	0.740
Interstitial lung disease	55	8.5%	85	9.6%	0.442
Ischemic heart disease	60	9.3%	83	9.4%	0.922
Psoriatic arthritis	41	6.3%	51	5.8%	0.656
Psoriasis	36	5.6%	38	4.3%	0.260
Pre-index non-biologic DMARD use (N, %)
Methotrexate	340	52.6%	536	60.8%	0.001
Corticosteroids	316	48.8%	362	41.1%	0.003
Pre-index biologic use (N, %)
No biologics	210	32.5%	513	58.2%	<0.001
Infliximab	137	21.2%	0	0.0%	<0.001
Abatacept	104	16.1%	62	7.0%	<0.001
Tocilizumab	83	12.8%	43	4.9%	<0.001
Adalimumab	64	9.9%	163	18.5%	<0.001
Etanercept	57	8.8%	139	15.8%	<0.001
Tofacitinib	31	4.8%	23	2.6%	0.023
Certolizumab pegot	40	6.2%	32	3.6%	0.020
Golimumab subcutaneous	22	3.4%	12	1.4%	0.008
Rituximab	18	2.8%	16	1.8%	0.206

Note:

a Calculations to determine DCI excludes rheumatologic disease.

b Number of unique diagnoses was the number of unique three-digit ICD-9-CM codes found pre-index.

Abbreviations: CIRAS, claims-based index for RA severity; DCI, Deyo–Charlson Comorbidity Index; DMARD, disease-modifying antirheumatic drug; GLM-IV, golimumab intravenous; ICD-9-CM, ICD Ninth Revision, Clinical Modification; IFX, infliximab; RA, rheumatoid arthritis.

Table 3 Demographic characteristics of matched patients

	GLM-IV N=547		IFX N=547		P-value
Age, years (mean, SD)	56.3	12.3	55.1	12.4	0.119
Age group (N, %)					0.601
18–34	22	4.0%	29	5.3%
35–44	60	11.0%	68	12.4%
45–54	160	29.3%	143	26.1%
55–64	196	35.8%	204	37.3%
65+	109	19.9%	103	18.8%
Sex (%, N)					1.000
Male	97	17.7%	97	17.7%
Female	450	82.3%	450	82.3%
Payer (N, %)					1.000
Commercial	431	78.8%	431	78.8%
Medicare	116	21.2%	116	21.2%
Length of follow-up, days (mean, SD)	609	161	613	163	0.688
Total all-cause pre-index health care costs, $ (mean, SD)	$43,118	$80,018	$38,396	$38,945	0.215

Abbreviations: GLM-IV, golimumab intravenous; IFX, infliximab.

Table 4 Clinical characteristics of matched patients

	GLM-IV N=547		IFX N=547		P-value
RA and comorbidity indices (mean, SD)
CIRAS	5.93	1.69	6.06	1.78	0.213
DCIa	0.73	1.15	0.71	1.29	0.824
Number of unique diagnosesb	20	10.74	21	11.30	0.337
Number of unique prescription drugs	18	10.47	20	10.41	0.017
Specific comorbid conditions (N, %)
Essential hypertension	240	43.9%	236	43.1%	0.807
Disorders of lipoid metabolism	176	32.2%	178	32.5%	0.897
Respiratory symptoms	171	31.3%	161	29.4%	0.511
Diabetes	100	18.3%	84	15.4%	0.196
Depression	62	11.3%	69	12.6%	0.514
Osteoporosis	60	11.0%	53	9.7%	0.487
Interstitial lung disease	49	9.0%	45	8.2%	0.666
Ischemic heart disease	47	8.6%	46	8.4%	0.914
Psoriatic arthritis	34	6.2%	35	6.4%	0.901
Psoriasis	27	4.9%	27	4.9%	1.000
Pre-index non-biologic DMARD use (N, %)
Methotrexate	301	55.0%	328	60.0%	0.099
Corticosteroids	261	47.7%	244	44.6%	0.303
Pre-index biologic use (N, %)
No biologics	209	38.2%	209	38.2%	1.000
Infliximab	106	19.4%	0	0.0%	<0.001
Abatacept	74	13.5%	55	10.1%	0.024
Tocilizumab	63	11.5%	37	6.8%	<0.001
Adalimumab	57	10.4%	143	26.1%	<0.001
Etanercept	44	8.0%	134	24.5%	<0.001
Tofacitinib	29	5.3%	22	4.0%	0.315
Certolizumab pegot	26	4.8%	30	5.5%	0.583
Golimumab subcutaneous	15	2.7%	11	2.0%	0.427
Rituximab	10	1.8%	14	2.6%	0.409

Note:

a Calculations to determine DCI excludes rheumatologic disease.

b Number of unique diagnoses was the number of unique three-digit ICD-9-CM codes found pre-index.

Abbreviations: CIRAS, claims-based index for RA severity; DCI, Deyo–Charlson Comorbidity Index; DMARD, disease-modifying antirheumatic drug; GLM-IV, golimumab intravenous; ICD-9-CM, ICD Ninth Revision, Clinical Modification; IFX, infliximab; RA, rheumatoid arthritis.

Table 5 Treatment patterns and infusion patterns

	GLM-IV N=547		IFX N=547		P-value
Days from last pre-index biologic dose to index date (mean, SD)	68.6	42.3	70.6	41.3	0.424
Duration of index therapy, days (mean, SD)	396	240	397	239	0.928
Patients who discontinued or switched (N, %)	294	53.7%	294	53.7%	1.000
Discontinued index medication (N, %)	119	21.8%	162	29.6%	0.003
Switched to a different biologic (N, %)	175	32.0%	132	24.1%	0.004
Days to discontinuation or switch (mean, SD)	241	165	244	171	0.799
Concomitant methotrexate use (N, %)	283	51.7%	283	51.7%	1.000
Days of concomitant methotrexate (mean, SD)	34.7%	39.4%	35.0%	40.4%	0.892
Concomitant corticosteroid use (N, %)	210	38.4%	268	49.0%	<0.001
Days of concomitant corticosteroids (mean, SD)	2.2%	4.3%	3.9%	6.6%	<0.001
Total number of index drug infusions	3,961		4,716
Number of infusions per patient (mean, SD)	7.2	4.3	8.6	5.6	0.018
1 (N, %)	30	5.5%	42	7.7%
2 (N, %)	57	10.4%	45	8.2%
3 (N, %)	54	9.9%	30	5.5%
4 (N, %)	50	9.1%	44	8.0%
5+ (N, %)	356	65.1%	386	70.6%
Vials per infusiona (mean, SD)	4.1	2.6	4.7	4.0	<0.001
Induction intervalsb,c (N, %)					<0.001
≤2 weeks	2	0.4%	296	30.7%
>2 weeks ≤3 weeks	4	0.8%	111	11.5%
>3 weeks ≤4 weeks	270	52.2%	259	26.8%
>4 weeks ≤5 weeks	127	24.6%	104	10.8%
>5 weeks ≤7 weeks	30	5.8%	94	9.7%
>7 weeks ≤9 weeks	55	10.6%	58	6.0%
>9 weeks	29	5.6%	43	4.5%
Maintenance intervalsb,c (N, %)					<0.001
≤4 weeks	55	1.9%	330	10.3%
>4 weeks ≤5 weeks	16	0.6%	228	7.1%
>5 weeks ≤7 weeks	100	3.5%	1,135	35.4%
>7 weeks ≤9 weeks	2,322	80.2%	1,237	38.6%
>9 weeksd	404	13.9%	274	8.6%
Interval durations, all intervals, days (mean, SD)	54.1	13.9	44.3	32.4	<0.001
Maintenance interval durations, days (mean, SD)	59.6	14.8	49.4	17.0	<0.001

Note:

a Vials per infusions were computed by dividing the amount paid by the wholesale acquisition cost.

b Count represents infusion intervals, not the number of infusions. For example, a patient with three infusions will have two infusion intervals.

c GLM-IV maintenance starts with the third dose, so dose interval two-to-three is the first GLM-IV maintenance interval. IFX maintenance starts with the fourth dose, so dose interval three-to-four is the first IFX maintenance interval.

d When maintenance infusion intervals exceeded 9 weeks, the average infusion interval waŝ12 weeks for both IFX and GLM-IV cohorts.

Abbreviations: GLM-IV, golimumab intravenous; IFX, infliximab.

Figure 2 Distribution of maintenance infusions.

Notes: ^aAll differences between cohorts for the proportions of maintenance infusions are significant at P<0.001. When maintenance infusion intervals exceeded 9 weeks, the average infusion interval waŝ12 weeks for both IFX and GLM-IV cohorts.
Abbreviations: GLM-IV, golimumab intravenous; IFX, infliximab.

Table 6 Drug and infusion expenditures

	GLM-IV N=547		IFX N=547
Drug costs per infusiona
Commercial (N)	3,090		3,700
Paid amount, $ (mean, SD)	$5,622	$3,641	$5,083	$4,339
Infusion costs per infusiona
All infusions with non-drug costs (N)	3,746		4,487
Commercial
Infusions with non-drug costs (N)	2,964		3,568
Paid amount, $ (mean, SD)	$224	$151	$360	$281

Note:

a Excludes claims with zero dollar costs.

Abbreviations: GLM-IV, golimumab intravenous; IFX, infliximab.

Figure 3 First-year costs of GLM-IV and IFX therapy comparing recommended dosing intervals and real-world dosing intervals in commercially insured patients.

Abbreviations: GLM-IV, golimumab intravenous; IFX, infliximab.