A first-in-class orally available HBV cccDNA destabilizer ccc_R08 achieved
sustainable HBsAg and cccDNA reduction in the HBV circle mouse model
*Yan Z, et al. HBV circle: A novel tool to investigate hepatitis B virus covalently closed circular DNA. J Hepatol 2017;66:1149–57.
Wang L, et al. ILC 2019; PS-074
BACKGROUND & AIMS
• Persistence of cccDNA is a major barrier to
cure in CHB patients with existing therapies
• Aim: To evaluate the effect of a novel small
molecule ccc_R08 on the level of pre-existing
cccDNA both in vitro and in vivo
METHODS
• HBV-infected primary human hepatocytes
(PHH) were used for evaluating antiviral
activities in vitro
• ccc_R08 was orally administered in HBV circle
mouse model* to study its in vivo efficacy
– Levels of HBV DNA, HBsAg, HBeAg, pgRNA,
and cccDNA were measured
RESULTS
HBV-infected PHH
• Potent inhibition of HBV DNA, HBsAg,
HBeAg, and pre-existing cccDNA
• No effect on mitochondrial DNA
level and cytotoxicity
HBV circle mice
• Levels of serum HBV DNA, pgRNA, HBsAg,
HBeAg reduced significantly
– Sustained during the off-treatment period
• Levels of cccDNA in the liver of ccc_R08
treated mice were < LLOQ
– ETV had no such effect on cccDNA level in
this model
A first-in-class orally available HBV cccDNA destabilizer ccc_R08 achieved
sustainable HBsAg and cccDNA reduction in the HBV circle mouse model
Wang L, et al. ILC 2019; PS-074
CONCLUSIONS A novel small molecule
ccc_R08 can sustainably reduce serum
HBsAg and liver cccDNA levels in the HBV
circle mouse model
0 7 1 4 2 1 2 8 3 5 4 2 4 9
1
2
3
4
5
L L O Q
D a y s p o s t 1 s t d o s e
L o g 1 0 ( I U / m l s e r u m )
Treatment End HBsAg Treatment End HBeAg
0 7 1 4 2 1 2 8 3 5 4 2 4 9
0 . 5
1 . 0
1 . 5
2 . 0
2 . 5
3 . 0
L L O Q
D a y s p o s t 1 s t d o s e
L o g 1 0 ( N C U / m l s e r u m )
Vehicle
Treatment End HBV DNA
ccc_R08
20 mg/kg
BID
L o g 1 0 ( c o p i e s / u l )
3
4
5
LLOQ
Vehicle
FIGURE HBV circle mouse model: serum levels of HBsAg, HBeAg, and HBV DNA and
cccDNA levels in the liver
ccc_R08
20 mg/kg BID
Liver
cccDNA level
HBV entry inhibition after IFNα treatment hinders HBV rebound in
hepatocytes negative for all HBV markers during IFN treatment
*MyrB treatment started 3 days before the last IFNα injection.
Allweiss L, et al. ILC 2019; PS-155
BACKGROUND & AIMS
• IFNα treatment can exert both immunomodulatory and antiviral effects
• Aims:
– Investigate these antiviral effects in HBV-infected human hepatocytes in vivo and whether they can
persist after treatment cessation
– Employ HBV entry inhibition to assess the role of new infections in HBV rebound
METHODS
• HBV-infected human liver chimeric mice were treated with PEG-IFNα for 6 weeks (n=13 + 5
untreated controls)
– Mice were either sacrificed (n=5) or treatment was stopped to assess serological/intrahepatic viral
changes for 6 further weeks, either in the presence (n=4) or absence of the entry inhibitor MyrB* (n=4)
– HBV load analyzed in serum and liver by qPCR
– RNA-ISH and immunofluorescence to visualize HBV transcription and presence of SMC6 (potential
marker of cccDNA suppression/clearance)
HBV entry inhibition after IFNα treatment hinders HBV rebound in
hepatocytes negative for all HBV markers during IFN treatment
Allweiss L, et al. ILC 2019; PS-155
CONCLUSIONS Reappearance of SMC6 in IFNα-treated human liver chimeric mice did not hinder
HBV reactivation after drug withdrawal. MyrB maintained HBV negativity in a large proportion of
hepatocytes, suggesting that they had cleared cccDNA during treatment and that new infection
events play a key role in HBV rebound post IFN treatment作者: snowxyxy 时间: 2019-4-22 21:48
EASL 2019 FRI-184
Function and drug combination studies in cell culture models for
AB-729, a subcutaneously administered siRNA investigational
agent for chronic hepatitis B infection
Amy C.H. Lee1, Emily P. Thi1, Andrea Cuconati1, Andrzej Ardzinski1,
Richard Holland1, Hui Huang1, Andrew S. Kondratowicz1,
Rose Kowalski1, Lorne Palmer1, Chris Pasetka1, Rene Rijnbrand1,
Holly M. Steuer1, Xiaohe Wang1, Xin Ye1, Michael J. Sofia1. 1Arbutus
Biopharma, Warminster, United States
Email: [email protected]
Background and aims: Developing a cure for chronic hepatitis B
must address viral persistence and likely requires combination of
drugs with different modes of action. AB-729 is a siRNA agent that
acts on all HBV RNA transcripts, enabling inhibition of HBV
replication and suppression of all viral antigens including HBsAg;
this may facilitate reinvigoration of host immune responses. A novel
high avidity N-acetylgalactosamine (GalNAc) moiety mediates
targeting of AB-729 to hepatocytes, the site of HBV infection. Here
we describe HBV cell culture models capable of demonstrating both
cellular entryand gene silencing functionalities of GalNAc-siRNA, and
present in vitro characterization of AB-729 anti-HBV activities as
monotherapy as well as in combination with approved and
investigational drug modalities.
Method: AB-729 activity was studied in adeno-associated virustransduced
HBV-expressing primary mouse hepatocytes (PMH),
HBV-infected primary human hepatocytes (PHH) and transientlyand
stably-transfected HBV cell lines. Drug combination studieswere
conducted using three-dimensional modeling for drug-drug interactions
and analyzed using MacSynergy II software.
Results: Asialoglycoprotein receptor (ASGPR) levels decreased
rapidly during in vitro culture of primary hepatocytes, providing a
narrow time window for GalNAc-mediated cellular entry of AB-729.
Congruent with this, EC50 shifts of 24- and at least 478-fold were
observed in PMH and PHH treated with GalNAc-siRNA at 4 h
compared to 24 h or 4 days post-plating. AB-729 reduced HBV RNA,
HBeAg and HBsAg expression, with 5.6-19.4 nM EC50 values in PMH.
Commercial transfection agent had to be utilized to conduct a
standard HBV genotype and resistance mutant susceptibility panel
for the siRNA component of AB-729. Pairwise testing with tenofovir
alafenamide, peg-interferon-alpha-2a and AB-506, a next-generation
investigational capsid inhibitor, showed that AB-729 was able to
combine productively with each of these drug modalities and
without significant effects on cell viability.
Conclusion: Standard HBV cell lines can be used to characterize the
activity of the AB-729 siRNA whereas two primary hepatocyte
systems were able to model both the cell entry functionality and
anti-HBV activities of AB-729. Preclinical investigations demonstrate
that AB-729 and AB-506 when combined have distinct but
mechanistically compatible antiviral activities and may feasibly be
used in future combination therapeutic regimens.作者: StephenW 时间: 2019-4-23 11:42