A Biodistribution Study of OTV vs. ASO by Intravenous or Intrathecal Administration in Cynomolgus Monkeys

The objective of this study is to evaluate ASO biodistribution and pharmacodynamic response following intravenous delivery of conjugated OTV, which utilizes transferrin-receptor binding to deliver ASO, vs. intrathecal delivery of naked ASO in cynomolgus monkeys, the current gold standard for ASO delivery. Three groups were included for comparison: 1) Negative control cohort = Four biweekly intravenous doses of saline (n=3); 2) IT cohort = Single intrathecal dose of 4mg MALAT1 ASO (n=3); 3)? OTV multi dose cohort = Four biweekly intravenous doses of 30mpk OTV:MALAT1 (n=3). Tissues were collected two weeks after the final dose to allow sufficient time for target knockdown. Brain, spinal cord, and peripheral tissues were dissected and frozen for molecular analysis. Compared to an intrathecal injection of ASO, systemic administration of OTV resulted in significantly more homogenous biodistribution of ASO in the central nervous system as measured by a probe-based hybridization assay as well as staining with an anti-ASO antibody. One potential consequence of heterogeneous ASO distribution is heterogeneous target knockdown throughout the CNS. We observed more consistent target knockdown throughout the cortex, subcortical areas, and spinal cord of monkeys dosed peripherally with OTV. By contrast, monkeys dosed intrathecally with naked ASO showed much more knockdown in the spinal cord compared to the brian, consistent with ASO distribution. Overall design: Single dose of 4mg MALAT1 ASO intrathecally (“ASO IT”), n=3 2)????Four biweekly doses of saline intravenously (“Saline” or “Vehicle”), n=3 3)????Four biweekly doses of 30mpk OTV:MALAT1 intravenously (“OTV IV”), n=3 Tissues were collected two weeks after the final dose to allow sufficient time for target knockdown. Brain tissue was dissected and frozen for pharmacodynamic analysis. Compared to an intrathecal injection of ASO, systemic administration of OTV resulted in significantly more widespread and homogenous biodistribution of ASO in the central nervous system as measured by staining with an anti-ASO antibody