Table 1.

Baseline characteristics for the total population

	Phase 3 parent trial		B-YOND (extension trial)
	B-LONG	Kids B-LONG	From B-LONG	From Kids B-LONG
Subjects enrolled, n	119∗	30	93	27
Median (range) age at the enrollment into the parent or extension study, y	30 (12-71)	5 (1-11)	29 (13-63)	7 (3-12)
Race, n (%)
White	70 (58.8)	22 (73.3)	47 (50.5)	19 (70.4)
Black	10 (8.4)	2 (6.7)	9 (9.7)	2 (7.4)
Asian	28 (23.5)	5 (16.7)	27 (29.0)	5 (18.5)
Other	11 (9.2)	1 (3.3)	10 (10.8)	1 (3.7)
Median (IQR) estimated ABR before the start of rFIXFc treatment (prestudy)†
Prior prophylactic regimen	2 (1-6); n = 41	2.5 (0-5); n = 30
Prior on-demand regimen	22 (12-33); n = 66	N/A
rFIXFc regimen, n‡
WP	63	30	51	23
Individualized IP	29	N/A	31	5
Modified prophylaxis	N/A	N/A	16	2
On-demand treatment	27	N/A	15	N/A

N/A, not applicable.

^∗Four of the 123 B-LONG subjects were enrolled in the surgery-only group and are not included here.

^†In the B-LONG study, 10 subjects had either missing prestudy ABR data or missing prestudy regimen, and 2 subjects received a prestudy sports prophylaxis regimen. Their prestudy ABRs were not included in this analysis.

^‡Subjects were permitted to switch treatment regimens on enrollment and at any time during the B-YOND study and may appear in ≥1 treatment regimen.