Integrated Assessment of Phase 2 Data on GalNAc₃-Conjugated 2'-O-Methoxyethyl-Modified Antisense Oligonucleotides

Receptor-mediated delivery of an antisense oligonucleotide (ASO) using the ligand-conjugated antisense technology is establishing a new benchmark for antisense therapeutics. The triantennary N-acetylgalactosamine (GalNAc₃) cluster is the first conjugated ligand to yield a marked increase in ASO potency for RNA targets expressed by hepatocytes, compared to the unconjugated form. In this study, we present an integrated safety assessment of data available from randomized, placebo-controlled, phase 2 studies for six GalNAc₃-conjugated 2'-O-methoxyethyl (2'MOE)-modified ASOs. The total study population included 642 participants (130 placebo; 512 ASO) with up to 1 year of exposure. The primary measures were the incidence of signals from standardized laboratory tests and the mean test results over time. The GalNAc₃-conjugated ASOs were well tolerated with no class effect identified across all doses tested compared to placebo. These results extend prior observations from phase 1 studies, now with treatment up to 1 year.