MODIFIED siRNA MOLECULES AND USES THEREOF

• US 20090270481A1
• Filed: 01/23/2009
• Published: 10/29/2009
• Est. Priority Date: 11/02/2005
• Status: Active Grant

• Current Assignee: Arbutus Biopharma Corporation
• Original Assignee: Protiva Biotherapeutics Inc (Arbutus Biopharma Corporation)
• Inventors: Judge, Adam, MacLachlan, Ian, Sood, Vandana, Lee, Amy C.H.
• Granted Patent: US 8,188,263 B2
• Time in Patent Office: Days
• US Class Current: 514/44.A
• CPC Class Codes: A61K 31/713 Double-stranded nucleic acids or oligonucleotides
• CPC Class Codes: A61K 48/00 Medicinal preparations containing genetic material which is inserted into cells of the living body to treat genetic diseases; Gene therapy
• CPC Class Codes: A61K 9/1272 with substantial amounts of non-phosphatidyl, i.e. non-acylglycerophosphate, surfactants as bilayer-forming substances, e.g. cationic lipids with cholesterol as the only non-phosphatidyl surfactant A61K9/127; lipids as modifying agent A61K47/543
• CPC Class Codes: C12N 15/111 General methods applicable to biologically active non-coding nucleic acids
• CPC Class Codes: C12N 15/113 Non-coding nucleic acids modulating the expression of genes, e.g. antisense oligonucleotides; Antisense DNA or RNA; Triplex- forming oligonucleotides; Catalytic nucleic acids, e.g. ribozymes; Nucleic acids used in co-suppression or gene silencing when used in plants C12N15/8218
• CPC Class Codes: C12N 2310/14 interfering N.A.
• CPC Class Codes: C12N 2310/351 Conjugate
• CPC Class Codes: C12N 2320/30 Special therapeutic applications
• CPC Class Codes: C12N 2320/51 modulating the chemical stability, e.g. nuclease-resistance

Abstract

The present invention provides chemically modified siRNA molecules and methods of using such siRNA molecules to silence target gene expression. Advantageously, the modified siRNA of the present invention is less immunostimulatory than its corresponding unmodified siRNA sequence and retains RNAi activity against the target sequence. The present invention also provides nucleic acid-lipid particles comprising a modified siRNA, a cationic lipid, and a non-cationic lipid, which can further comprise a conjugated lipid that inhibits aggregation of particles. The present invention further provides methods of silencing gene expression by administering a modified siRNA to a mammalian subject. Methods for identifying and/or modifying an siRNA having immunostimulatory properties are also provided.

Claims

1. A modified siRNA that silences Apolipoprotein B (ApoB) expression, wherein the modified siRNA comprises an antisense strand sequence consisting of SEQ ID NO:

51.

2. The modified siRNA of claim 1, further comprising a sense strand sequence consisting of SEQ ID NO:

50.

3. The modified siRNA of claim 1, wherein the modified siRNA is less immunostimulatory than a corresponding unmodified siRNA sequence.

4. A pharmaceutical composition comprising a modified siRNA of claim 1 and a pharmaceutically acceptable carrier.

5. A nucleic acid-lipid particle comprising:

(a) a modified siRNA of claim 1;

(b) a cationic lipid; and

(c) a non-cationic lipid.

6. The nucleic acid-lipid particle of claim 5, further comprising a conjugated lipid that inhibits aggregation of particles.

7. The nucleic acid-lipid particle of claim 6, wherein the conjugated lipid that inhibits aggregation of particles comprises a polyethyleneglycol (PEG)-lipid conjugate.

8. The nucleic acid-lipid particle of claim 7, wherein the PEG-lipid conjugate comprises a PEG-dialkyloxypropyl (PEG-DAA) conjugate.

9. The nucleic acid-lipid particle of claim 5, further comprising cholesterol.

10. The nucleic acid-lipid particle of claim 5, wherein the modified siRNA is fully encapsulated in the nucleic acid-lipid particle.

11. A pharmaceutical composition comprising a nucleic acid-lipid particle of claim 5 and a pharmaceutically acceptable carrier.