A real-world evidence analysis of the impact of switching from factor VIII to emicizumab prophylaxis in patients with hemophilia A without inhibitors

Figures & data

Figure 1. Study design

Table 1. Demographic characteristics.

	Participants who switched from FVIII to emicizumab prophylaxis N = 131
Index year, years (%)
2017	0 (0.0)
2018	19 (14.5)
2019	80 (61.1)
2020	32 (24.4)
Age, years
Mean (SD)	28.9 (18.6)
Median	25
Range	28
Minimum	3
Maximum	83
IQR	13–41
Age group, n (%)
0–2 years	0 (0.0)
3–6 years	11 (8.4)
7–12 years	21 (16.0)
13–17 years	13 (9.9)
18–26 years	22 (16.8)
> 26 years	64 (48.9)
Sex, n (%)
Male	131 (100)
Female	0 (0.0)
Payer channel, n (%)
Commercial	70 (53.4)
Medicaid	50 (38.2)
Medicare	11 (8.4)
VA/Other	0 (0.0)
Geographic region, n (%)
Northeast	26 (19.8)
Midwest	43 (32.8)
South	33 (25.2)
West	29 (22.1)
Other	0 (0.0)

FVIII: factor VIII; SD: standard deviation.

Table 2. ABR_b outcomes.

	Pre-switch N = 131	Post-switch N = 131	P-value
Total number of bleed events, n	82	45
ABRb, mean (SD)	0.25 (0.69)	0.20 (0.72)	0.4456
ABRb by bleed type, mean (SD)
Spontaneous bleeds	0.23 (0.68)	0.18 (0.71)	0.5173
Spontaneous bleeds: joint	0.18 (0.60)	0.18 (0.71)	0.9630
Traumatic bleeds	0.02 (0.09)	0.01 (0.09)	0.4388
Traumatic bleeds: joint	0.00 (0.03)	0.01 (0.06)	0.4758
ABRb by age group, mean (SD)
0–2 years	N/A	N/A	N/A
3–6 years	0.11 (0.21)	0 (0.00)	0.1060
7–12 years	0.42 (1.00)	0.37 (1.42)	0.8739
13–17 years	0.15 (0.29)	0.05 (0.17)	0.1709
18–26 years	0.35 (0.75)	0.28 (0.73)	0.7320
> 26 years	0.21 (1.00)	0.17 (0.46)	0.6927
ABRb by payer channel, mean (SD)
Commercial	0.14 (0.34)	0.26 (0.90)	0.1824
Medicaid	0.43 (1.00)	0.16 (0.45)	0.0560
Medicare	0.16 (0.39)	0 (0.00)	0.2045
ABRb by CCI, mean (SD)
0	0.25 (0.72)	0.20 (0.74)	0.5850
1	0.14 (0.29)	0 (0.00)	0.1079
2	1.01 (0.26)	0.86 (1.49)	0.8773
3+	0.17 (0.16)	0.17 (0.30)	0.9956

ABR_b: billed annualized bleed rates; CCI: Charlson Comorbidity Index; N/A; not applicable; SD: standard deviation.

Table 3. Correlation analysis of pre- versus post-ABR_b.

	SD pre-switch	SD post-switch	SDd	Correlation
ABRb	0.6874	0.7166	0.8392	0.2860
Spontaneous ABRb	0.6824	0.7137	0.8344	0.2862
Traumatic ABRb	0.0885	0.0917	0.1292	−0.0278
Spontaneous joint ABRb	0.5966	0.7137	0.8261	0.2147
Traumatic joint ABRb	0.0282	0.0647	0.0710	−0.0152

ABR_b: billed annualized bleed rate; SD_d: standard deviation of the difference.

Table 4. Average follow-up days for study patients and estimate of follow-up time after March 2020 between pre- and post-switch patients.

Exploratory outcomes	Pre-switch N = 131					Post-switch N = 131					P-value
	Mean/N	SD	Median	Range (IQR)	Min, max	Mean/N	SD	Median	Range (IQR)	Min, max
Average follow-up days for study patients	978.37	555.03	930	867 (481, 1348)	205, 2308	522.26	191.36	537	303.5 (370, 674)	209, 884	<0.0001
Average follow-up days after March 2020	12.2	34.76	0	0 (0, 0)	0, 156	293.72	118.43	364	78.5 (287, 365)	0, 365	<0.0001

IQR: interquartile range; max: maximum; min: minimum; SD: standard deviation.

Table 5. Bleeding events by type and site.

	Pre-switch N = 131		Post-switch N = 131		P-value
	Number (spontaneous and traumatic – primary)	% of bleeds	Number (spontaneous and traumatic – primary)	% of bleeds
All bleeds, n	82	N/A	45	N/A	0.9491
Spontaneous bleeds, n
All	73	100%	42	100%	0.9505
Joint	64	88%	42	100%	0.9105
Soft tissue (muscles)	1	1%	0	0%	N/A
Intracranial	2	3%	0	0%	N/A
Gastrointestinal	2	3%	0	0%	N/A
Genitourinary	0	0%	0	0%	N/A
Intracavity	0	0%	0	0%	N/A
Perinatal	0	0%	0	0%	N/A
Facial	4	5%	0	0%	N/A
Other sites	0	0%	0	0%	N/A
Traumatic bleeds, n
All	9	100%	3	100%	N/A
Joint	2	22%	2	67%	N/A
Soft tissue (muscles)	2	22%	0	0%	N/A
Intracranial	0	0%	0	0%	N/A
Gastrointestinal	0	0%	0	0%	N/A
Genitourinary	0	0%	0	0%	N/A
Intracavity	1	11%	0	0%	N/A
Perinatal	0	0%	0	0%	N/A
Facial	1	11%	0	0%	N/A
Other sites	3	33%	1	33%	N/A

N/A: not applicable.

Data availability statement

The data underlying this article were provided by STATinMED via confidential license agreement, which has legally enforceable usability restrictions that preclude our making the data available publicly.