Patent ID: 7915399

Claim:
A method for generating a chemically modified double-stranded short interfering nucleic acid (siNA) molecule that directs cleavage of a target RNA via RNA interference and has reduced immunostimulatory properties compared to a corresponding siNA molecule having unmodified nucleotides, said method comprising: (a) introducing 2′-O-methyl (2′OMe) nucleotides in one or more of the nucleotide positions of the siNA molecule, wherein (i) each strand of said siNA molecule is about 18 to about 38 nucleotides in length; (ii) one strand of said siNA molecule comprises a nucleotide sequence having sufficient complementarity to said target RNA for the siNA molecule to direct cleavage of the target RNA via RNA interference; (iii) said siNA molecule does not comprise phosphorothioate backbone modifications; and (iv) said 2′OMe nucleotides are not 2′OMe-cytosine nucleotides; and (b) assaying the siNA molecule of step (a) under conditions suitable for isolating an siNA molecule having reduced immunostimulatory properties compared to a corresponding siNA molecule having unmodified nucleotides wherein said reduced immunostimulatory properties comprise an abrogated or reduced induction of inflammatory or pro-inflammatory cytokines and/or an abrogated or reduced induction of Toll Like Receptors (TLRs) in response to the siNA being introduced in a cell, tissue, or organism.