Patent ID: 8796239

Claim:
A double-stranded nucleic acid having structure (A) set forth below: (A) 5′ N 1 -(N)x-Z 3′ (antisense strand) 3′ Z′-N 2 -(N′)y-z″ 5′ (sense strand) wherein each of N 2 , N and N′ is an unmodified ribonucleotide, a modified ribonucleotide, or an unconventional moiety; wherein each of (N)x and (N′)y is an oligonucleotide in which each consecutive N or N′ is joined to the adjacent N or N′ by a covalent bond; wherein x=y=18; wherein the sequence of N 2 —(N′)y is fully complementary to the sequence of N 1 —(N)x and the sequence of (N)x has complementarity to a consecutive sequence in a target RNA; wherein N 1 is covalently bound to (N)x and not complementary to the corresponding nucleotide in the target RNA or is an unconventional moiety complementary to the target RNA; wherein: N 1 is selected from the group consisting of adenosine and deoxyadenosine when the corresponding nucleotide in the target RNA sequence is adenosine; or N 1 is selected from the group consisting of adenosine, deoxyadenosine and deoxythymidine when the corresponding nucleotide in the target RNA sequence is cytidine; or N 1 is selected from the group consisting of adenosine, deoxyadenosine and deoxythymidine when the corresponding nucleotide in the target RNA sequence is guanosine; or N 1 is selected from the group consisting of uridine and deoxyuridine when the corresponding nucleotide in the target RNA sequence is uridine; wherein z″ may be present or absent, but if present is a capping moiety covalently attached at the 5′ terminus of N 2 —(N′)y; and wherein each of Z and Z′ is independently present or absent, but if present is independently 1-5 consecutive nucleotides, 1-5 consecutive non-nucleotide moieties or a combination of 1-5 nucleotides and non-nucleotide moieties, covalently attached at the 3′ terminus of the strand in which it is present; or a pharmaceutically acceptable salt of the double stranded nucleic acid.