Table 6.
Pre-existing AAV Immunity and Subsequent T Cell Responses
| AAV555 | rAAV2hFIX44 | AAV5-hFIXWT 23, 33 | SPK-900125 | scAAV2/8- LP1-hFIXco 21, 22 | AAV5-FVIII24 | AAVrh10 62, 67 | |
|---|---|---|---|---|---|---|---|
| Study type | non-human primate | clinical | clinical | clinical | clinical | clinical | clinical |
| Pre-existing immunity | yes | 1/2 (1:2 and 1:17) | 3/10 | 1/10 | no | no | yes (NAb titer < 1:5) |
| T cell response | no | 1 (not in the participant with pre-existing immunity) | no | 2/10 (not participants with pre-existing immunity) | 8/10 (intermediate and high dose group) | no | yes 6/6 |
| Efficacy in participants with pre-existing immunity | no | no | yes | yes, but FIX expression lowest (approx. 10%–15%) | not applicable | not applicable | yes |
| Loss of FIX expression over time in participants with pre-existing immunity | not applicable | yes, peaked at 2 weeks | no | no | not applicable | not applicable | yes, peaked between 3-14 weeks |
NAb, neutralizing antibody.