Mononuclear cell inflammation in NHP neural tissue; clinically all patients developed high anti-AAV9 titers, anti-SMN in ~7%
“Anti-AAV9 antibody responses were consistent and robust across all studies, with all participants developing high titers that remained elevated through study completion.”
✓ VerifiedFDA summary basis for approval, p. 17Source ↗
Biodistribution & persistence
Highest in liver, DRG, spinal cord; lower peripheral incl. gonads; clinical shedding mainly fecal, >90% within 2 weeks
“Biodistribution (BD) of OAV101 demonstrated the highest titers in the liver, DRG, and spinal cord, with lower levels reported in the periphery, including gonads.”
✓ VerifiedFDA summary basis for approval, p. 16Source ↗
Modality-specific risk
AAV9 DRG/neuronal toxicity and hepatotoxicity after IT dosing, precluding NOAEL; vector immunity
“Elevated liver enzyme levels (aspartate and alanine amino transferase) and single cell necrosis of hepatocytes were observed in select NHPs at 6 weeks post-administration but resolved by 12 months post-administration.”
Not reported in the public reviews. Reviewers summarise selectively, so this usually means it wasn't discussed publicly, not that it wasn't studied.
Anti-drug antibodies: patients
Anti-AAV9 titers rose in all patients (median ≥1:819,200 at 12 months); anti-SMN antibodies in 6.7% and 7.4%
“Increases from baseline in anti-AAV9 antibody titers were reported in all patients with a median anti-AAV9 antibody titers of ≥ 1:819,200 at 12 months following ITVISMA injection in both studies. During the 12-month period following ITVISMA injection in Study 1 and Study 2, positive anti-SMN antibodies were observed in 5/75 (6.7%) and 2/27 (7.4%) of ITVISMA-treated patients, respectively.”