1. Academic Validation
  2. Safety evaluation of 2'-deoxy-2'-fluoro nucleotides in GalNAc-siRNA conjugates

Safety evaluation of 2'-deoxy-2'-fluoro nucleotides in GalNAc-siRNA conjugates

  • Nucleic Acids Res. 2019 Apr 23;47(7):3306-3320. doi: 10.1093/nar/gkz140.
Maja M Janas 1 Ivan Zlatev 1 Ju Liu 1 Yongfeng Jiang 1 Scott A Barros 1 Jessica E Sutherland 1 Wendell P Davis 1 Jingxuan Liu 1 Christopher R Brown 1 Xiumin Liu 1 Mark K Schlegel 1 Lauren Blair 1 Xuemei Zhang 1 Biplab Das 1 Chris Tran 1 Krishna Aluri 1 Jing Li 1 Saket Agarwal 1 Ramesh Indrakanti 1 Klaus Charisse 1 Jayaprakash Nair 1 Shigeo Matsuda 1 Kallanthottathil G Rajeev 1 Tracy Zimmermann 1 Laura Sepp-Lorenzino 1 Yuanxin Xu 1 Akin Akinc 1 Kevin Fitzgerald 1 Akshay K Vaishnaw 1 Peter F Smith 1 Muthiah Manoharan 1 Vasant Jadhav 1 Jing-Tao Wu 1 Martin A Maier 1
Affiliations

Affiliation

  • 1 Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA.
Abstract

For oligonucleotide therapeutics, chemical modifications of the sugar-phosphate backbone are frequently used to confer drug-like properties. Because 2'-deoxy-2'-fluoro (2'-F) nucleotides are not known to occur naturally, their safety profile was assessed when used in revusiran and ALN-TTRSC02, two short interfering RNAs (siRNAs), of the same sequence but different chemical modification pattern and metabolic stability, conjugated to an N-acetylgalactosamine (GalNAc) ligand for targeted delivery to hepatocytes. Exposure to 2'-F-monomer metabolites was low and transient in rats and humans. In vitro, 2'-F-nucleoside 5'-triphosphates were neither inhibitors nor preferred substrates for human polymerases, and no obligate or non-obligate chain termination was observed. Modest effects on cell viability and mitochondrial DNA were observed in vitro in a subset of cell types at high concentrations of 2'-F-nucleosides, typically not attained in vivo. No apparent functional impact on mitochondria and no significant accumulation of 2'-F-monomers were observed after weekly administration of two GalNAc-siRNA conjugates in rats for ∼2 years. Taken together, the results support the conclusion that 2'-F nucleotides can be safely applied for the design of metabolically stabilized therapeutic GalNAc-siRNAs with favorable potency and prolonged duration of activity allowing for low dose and infrequent dosing.

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