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Potent and persistent in vivo anti-HBV activity of chemically modified siRNAs


The efficacy of lipid-encapsulated, chemically modified short interfering RNA (siRNA) targeted to hepatitis B virus (HBV) was examined in an in vivo mouse model of HBV replication. Stabilized siRNA targeted to the HBV RNA was incorporated into a specialized liposome to form a stable nucleic-acid-lipid particle (SNALP) and administered by intravenous injection into mice carrying replicating HBV. The improved efficacy of siRNA-SNALP compared to unformulated siRNA correlates with a longer half-life in plasma and liver. Three daily intravenous injections of 3 mg/kg/day reduced serum HBV DNA >1.0 log10. The reduction in HBV DNA was specific, dose-dependent and lasted for up to 7 d after dosing. Furthermore, reductions were seen in serum HBV DNA for up to 6 weeks with weekly dosing. The advances demonstrated here, including persistence of in vivo activity, use of lower doses and reduced dosing frequency are important steps in making siRNA a clinically viable therapeutic approach.

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Figure 1: HBV-specific siRNAs and in vitro potency.
Figure 2: Pharmacokinetic analysis of siRNAs.
Figure 3: Cytokine induction and toxicities associated with unmodified and chemically stabilized siRNA.
Figure 4: Activity of systemically administered siRNA-SNALP in an HBV mouse model.


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The authors would like to thank Roger Aitchison for statistical analysis, and Adrianna Wells for manuscript preparation.

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Corresponding author

Correspondence to David V Morrissey.

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The authors declare no competing financial interests.

Supplementary information

Supplementary Fig. 1

SNALP Lipids. (PDF 70 kb)

Supplementary Fig. 2

SNALP Structure. (PDF 685 kb)

Supplementary Fig. 3

In vivo localization of SNALP formulated Cy3-labeled siRNA in mouse livers. (PDF 481 kb)

Supplementary Fig. 4

Chemically stabilized HBV siRNA do not induce local interferon production in the liver. (PDF 81 kb)

Supplementary Fig. 5

Chemically stabilized HBV siRNA do not induce local interferon-beta production in the liver. (PDF 90 kb)

Supplementary Fig. 6

NOD.scid mice generate robust Interferon to unmodified siRNA. (PDF 47 kb)

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Morrissey, D., Lockridge, J., Shaw, L. et al. Potent and persistent in vivo anti-HBV activity of chemically modified siRNAs. Nat Biotechnol 23, 1002–1007 (2005).

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