1 research outputs found
Efficient Synthesis and Biological Evaluation of 5′-GalNAc Conjugated Antisense Oligonucleotides
Conjugation of triantennary <i>N</i>-acetyl galactosamine
(GalNAc) to oligonucleotide therapeutics results in marked improvement
in potency for reducing gene targets expressed in hepatocytes. In
this report we describe a robust and efficient solution-phase conjugation
strategy to attach triantennary GalNAc clusters (mol. wt. ∼2000)
activated as PFP (pentafluorophenyl) esters onto 5′-hexylamino
modified antisense oligonucleotides (5′-HA ASOs, mol. wt. ∼8000
Da). The conjugation reaction is efficient and was used to prepare
GalNAc conjugated ASOs from milligram to multigram scale. The solution
phase method avoids loading of GalNAc clusters onto solid-support
for automated synthesis and will facilitate evaluation of GalNAc clusters
for structure activity relationship (SAR) studies. Furthermore, we
show that transfer of the GalNAc cluster from the 3′-end of
an ASO to the 5′-end results in improved potency in cells and
animals