Summary of anti-hFIX IgG antibody formation in dogs
Treatment group . | Dogs with antibodies* . | Identifying no. . | Peak relative IgG, μg/mL . | Peak immunoassay titer . | Inhibitor titer, BU/mL† . |
|---|---|---|---|---|---|
| Dogs transduced at birth‡ | 0 of 5 | — | 0 | < 1:100 | < 1 |
| Dogs transduced at 8-11 wk§ | 2 of 3 | M1595 | 0 | < 1:100 | < 1 |
| B85 | 41 | 1:800 | < 1 | ||
| B90 | 19 | 1:400 | < 1 | ||
| Dogs injected with 10 doses hFIX protein starting at 8 wk∥ | 3 of 3 | M1641 | 631 | 1:102 400 | 2 |
| M1644 | 252 | 1:25 600 | 5 | ||
| M1645 | 10 | 1:200 | < 1 |
Treatment group . | Dogs with antibodies* . | Identifying no. . | Peak relative IgG, μg/mL . | Peak immunoassay titer . | Inhibitor titer, BU/mL† . |
|---|---|---|---|---|---|
| Dogs transduced at birth‡ | 0 of 5 | — | 0 | < 1:100 | < 1 |
| Dogs transduced at 8-11 wk§ | 2 of 3 | M1595 | 0 | < 1:100 | < 1 |
| B85 | 41 | 1:800 | < 1 | ||
| B90 | 19 | 1:400 | < 1 | ||
| Dogs injected with 10 doses hFIX protein starting at 8 wk∥ | 3 of 3 | M1641 | 631 | 1:102 400 | 2 |
| M1644 | 252 | 1:25 600 | 5 | ||
| M1645 | 10 | 1:200 | < 1 |
Number of animals with antibodies was determined out of the total number evaluated.
Bethesda titer was determined for the sample with the highest levels of anti-hFIX IgG or for the sample collected at the last time point.
Dogs were injected with 3.2 × 109 TU/kg hAAT-hFIX-WPRE at 2 or 3 days after birth and were never stimulated with hFIX protein injections. These are the same dogs whose hFIX antigen and anti-hFIX antibody levels are shown in Figure 5A,C.
Dogs were injected with 5 × 108 TU/kg hAAT-hFIX-WPRE at 8 weeks after birth (B85 and B90) or 2 × 108 TU/kg hAAT-hFIX-WPRE at 11 weeks after birth (M1595) and were never stimulated with hFIX protein. These are the same dogs whose hFIX antigen and anti-hFIX antibody levels are shown in Figure 5B,D.
Dogs that did not receive gene transfer were injected intravenously with 10 doses of 30 IU/kg hFIX beginning at 8 weeks after birth. These are the same dogs whose anti-hFIX antibody levels are shown in Figure 5E.