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本帖最后由 StephenW 于 2019-4-14 23:53 编辑
PS-074
A first-in-class orally available HBV cccDNA destabilizer ccc_R08 achieved sustainable HBsAg
and HBV DNA suppression in the HBV circle mouse model through elimination of cccDNA-like
molecules in the mouse liver
Li Wang1, Qihui Zhu1, Jing Zeng1, Zhipeng Yan1, Andrew Feng1, John Young2, Lu Gao1
1Roche Innovation Centre Shanghai, Shanghai, China; 2Roche Innovation Centre Basel, Basel,
Switzerland
Email: [email protected]
Background and aims: The persistence of covalently closed circular DNA (cccDNA) in the nuclei of
infected hepatocytes is a major barrier for achieving cure with existing therapies in chronic hepatitis B
(CHB) patients. Therapeutic agents that can reduce the level of pre-existing cccDNA are needed to
achieve the goal of cccDNA eradication. Here we report the discovery of a novel small molecule,
ccc_R08, which reduces pre-existing cccDNA both in vitro and in vivo.
Method: Primary human hepatocytes (PHH) were used for HBV infection experiments and evaluation
of antiviral activities. The HBVcircle mouse model was used to study in vivo efficacy. Compound
treatment was initiated after viral persistence established. The levels of HBV DNA, pgRNA, HBsAg,
HBeAg were measured by quantitative polymerase chain reaction (qPCR), HBsAg chemiluminescent
immunoassay (CLIA), and HBeAg CLIA kits, respectively. cccDNA from infected hepatocytes and
mouse liver was measured with Southern Blot or qPCR after Hirt DNA extraction.
Results: We observed potent and dose-dependent inhibition of HBV DNA, HBsAg, and HBeAg upon
ccc_R08 treatment initiated two days after HBV infection in PHH. More importantly, the pre-existing
level of cccDNA was reduced significantly by ccc_R08 in HBV infected PHH. ccc_R08 did not show
any significant cytotoxicity in PHH or in multiple proliferating cell lines at up to 100 μM. No significant
effect on mitochondrial DNA was observed, indicating a specific effect on cccDNA. In vivo efficacy was
evaluated in the HBVcircle mouse model, in which HBV replication was driven by cccDNA-like
molecules. ccc_R08 was orally dosed twice daily for two weeks. Notably, the levels of serum HBV
DNA, pgRNA, HBsAg, HBeAg were significantly reduced, and sustained during the off-treatment
follow-up period. Moreover, at the end of follow-up, levels of cccDNA molecules in the liver of ccc_R08
treated mice were reduced to below lower limit of quantification (LLOQ). As a control, entecavir did not
impact cccDNA level in this model. In summary, these results demonstrate that ccc_R08 can reduce
pre-existing cccDNA.
Conclusion: We have reported results that a novel small molecule ccc_R08 can substantially reduce
cccDNA levels in HBV infected hepatocytes and in HBVcircle mouse model. These data encourage
exploration of this type of molecule in the clinic to evaluate its potential for curing CHB infection. |
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