| . | Inhibitor negative (n = 75) . | Inhibitor positive . | ||
|---|---|---|---|---|
| Total (n = 28) . | High-titer (n = 14)‡ . | Low-titer (n = 14) . | ||
| Median (range) age, mo§ | 7.4 (0.24-48.0) | 6.7 (0.96-24.0) | 7.2 (1.8-13.8) | 6.2 (0.96-24.0) |
| <1 y old, n (%) | 58 (77.3) | 22 (78.6) | 11 (78.6) | 11 (78.6) |
| ≥1 y old, n (%) | 17 (22.7) | 6 (21.4) | 3 (21.4) | 3 (21.4) |
| Race, n (%) | ||||
| White | 59 (78.7) | 20 (71.4) | 10 (71.4) | 10 (71.4) |
| Black or African American | 1 (1.3) | 1 (3.6) | 0 | 1 (7.1) |
| Other | 11 (14.7) | 7 (25.0) | 4 (28.6) | 3 (21.4) |
| Not reported | 4 (5.3) | 0 | 0 | 0 |
| Ethnicity, n (%) | ||||
| Hispanic or Latino | 12 (16.0) | 5 (17.9) | 3 (21.4) | 2 (14.3) |
| Not Hispanic or Latino | 55 (73.3) | 21 (75.0) | 9 (64.3) | 12 (85.7) |
| Not reported | 8 (10.7) | 2 (7.1) | 2 (14.3) | 0 |
| Genotype, n (%) | ||||
| Low-risk variants | ||||
| Missense‖ | 3 (4.0) | 1 (3.6) | 0 | 1 (7.1) |
| Splice site change‖ | 3 (4.0) | 0 | 0 | 0 |
| High-risk variants4 | ||||
| P value† | — | — | .0284 | — |
| Intron 22 inversion | 33 (44.0) | 14 (50.0) | 6 (42.9) | 8 (57.1) |
| Frameshift | 14 (18.7) | 2 (7.1) | 0 | 2 (14.3) |
| Nonsense¶ | 6 (8.0) | 4 (14.3) | 2 (14.3) | 2 (14.3) |
| Large structural change (>50 base pairs)¶ | 2 (2.7) | 3 (10.7) | 3 (21.4) | 0 |
| Exon 7 deletion (no frameshift) | 1 (1.3) | 0 | 0 | 0 |
| Unknown variants | 13 (17.3) | 4 (14.3) | 3 (21.4) | 1 (7.1) |
| Family history of inhibitors, n (%) | ||||
| P value† | — | — | .0176 | — |
| Yes | 11 (14.7) | 9 (32.1) | 6 (42.9) | 3 (21.4) |
| No | 56 (74.7) | 15 (53.6) | 6 (42.9) | 9 (64.3) |
| Unknown | 8 (10.7) | 4 (5.3) | 2 (14.3) | 2 (14.3) |
| . | Inhibitor negative (n = 75) . | Inhibitor positive . | ||
|---|---|---|---|---|
| Total (n = 28) . | High-titer (n = 14)‡ . | Low-titer (n = 14) . | ||
| Median (range) age, mo§ | 7.4 (0.24-48.0) | 6.7 (0.96-24.0) | 7.2 (1.8-13.8) | 6.2 (0.96-24.0) |
| <1 y old, n (%) | 58 (77.3) | 22 (78.6) | 11 (78.6) | 11 (78.6) |
| ≥1 y old, n (%) | 17 (22.7) | 6 (21.4) | 3 (21.4) | 3 (21.4) |
| Race, n (%) | ||||
| White | 59 (78.7) | 20 (71.4) | 10 (71.4) | 10 (71.4) |
| Black or African American | 1 (1.3) | 1 (3.6) | 0 | 1 (7.1) |
| Other | 11 (14.7) | 7 (25.0) | 4 (28.6) | 3 (21.4) |
| Not reported | 4 (5.3) | 0 | 0 | 0 |
| Ethnicity, n (%) | ||||
| Hispanic or Latino | 12 (16.0) | 5 (17.9) | 3 (21.4) | 2 (14.3) |
| Not Hispanic or Latino | 55 (73.3) | 21 (75.0) | 9 (64.3) | 12 (85.7) |
| Not reported | 8 (10.7) | 2 (7.1) | 2 (14.3) | 0 |
| Genotype, n (%) | ||||
| Low-risk variants | ||||
| Missense‖ | 3 (4.0) | 1 (3.6) | 0 | 1 (7.1) |
| Splice site change‖ | 3 (4.0) | 0 | 0 | 0 |
| High-risk variants4 | ||||
| P value† | — | — | .0284 | — |
| Intron 22 inversion | 33 (44.0) | 14 (50.0) | 6 (42.9) | 8 (57.1) |
| Frameshift | 14 (18.7) | 2 (7.1) | 0 | 2 (14.3) |
| Nonsense¶ | 6 (8.0) | 4 (14.3) | 2 (14.3) | 2 (14.3) |
| Large structural change (>50 base pairs)¶ | 2 (2.7) | 3 (10.7) | 3 (21.4) | 0 |
| Exon 7 deletion (no frameshift) | 1 (1.3) | 0 | 0 | 0 |
| Unknown variants | 13 (17.3) | 4 (14.3) | 3 (21.4) | 1 (7.1) |
| Family history of inhibitors, n (%) | ||||
| P value† | — | — | .0176 | — |
| Yes | 11 (14.7) | 9 (32.1) | 6 (42.9) | 3 (21.4) |
| No | 56 (74.7) | 15 (53.6) | 6 (42.9) | 9 (64.3) |
| Unknown | 8 (10.7) | 4 (5.3) | 2 (14.3) | 2 (14.3) |
Percentages are based on the number.
Safety analysis set.
Statistical testing was by inhibitor status (negative vs high titer or negative vs low titer) using Fisher exact test; unless otherwise specified, P > .05.
Seven of these patients initially developed an LTI followed by subsequent HTI.
Age at the time of informed consent.
Two patients previously classified as high risk have been reclassified as low risk: 1 missense variant (HGVS F8 c.6683G>A) in exon 24 of the F8 gene and 1 splice site variant (HGVS F8 c.5999-1G>T) in intron 18 of the F8 gene.
Considering nonsense and large structural change variants as 1 category, there is a difference in genotype risk between those in the HTI group and those who were inhibitor negative (P = .031).