HBV: What is in the Pipeline? - Virology...

Shyam Kottilil MD, Ph.D.Institute of Human Virology

University of MarylandBaltimore MD

HBV: What is in the Pipeline?

Disclosures

No conflict of interest to disclose

Unlabeled/Unapproved Use

New agents/drugs that are not yet FDA approved will be discussed

Adapted from Rehermann B and Mascimbeni M Nat Rev Immunol 5: 1573, 2005

Persistence of Hepatitis B

100

50

0Incr

ease

(% o

f max

imum

)

0 1 2 3 4 5 6 7 8Time After Infection (months)

SerumALT Activity

SerumHBVDNA

Outcome: Clinical Recovery

IncubationPhase

Acute Disease,Clinical Symptoms

Recovery,Protective Immunity

HBcAg-specific antibodies

100

50

0Incr

ease

(% o

f max

imum

)0 10 20 21 30 31 4041 50

Time After Infection (years)

SerumALT Activity

SerumHBV DNA

Immuno-tolerance

ImmunoactivePhase

Low Replicative

Phase

High Replicative

Phase

Outcome: Chronic Hepatitis

HBeAg-specific antibodiesSerum HBeAg

Serum HBsAg HBsAg-specific antibodies

HBcAg-specific antibodies

HBeAg-specific antibodiesSerum HBeAg

Serum HBsAg

Current HBV Treatment

Nucleos(t)ides

Entecavir

N

NN

NNH2

OPOHO

HO

N

NN

NNH2

OPO

HOHO

CH3

AdefovirTenofovir

HO

NH

NN

NO

NH2

OH

Interferons

O

S

N

N

NH2

OOH

Lamivudine

O

HN

N

O

OOH

CH3

OH

Telbivudine

Pegylated Interferon alfa 2a

Pegylated Interferon alfa 2b

Efficacy of HBV Agents After One Year of Therapy

Data from 2012 EASL HBV Management Guidelines

100

80

60

40

20

0

ALT

Nor

mal

izat

ion

(% p

atie

nts

at 1

yea

r)

Tenofovir Entecavir Telbivudine Lamivudine Adefovir PEG-IFN-2a

HBeAg+

HBeAg–

Effects of Treatment on Fibrosis

74% of Patients with Cirrhosis at Baseline Were No Longer Cirrhotic at Year 5

Baseline Ishak Fibrosis Score

No ImprovementImprovement

P <0.001: Jonckheere-Terpstra trend test

Marcellin, P et al. Lancet 2013; 381(9865):468-75

100

90

80

70

60

50

403020

10

0

Perc

enta

ge o

f Pat

ient

s

1 2 3 4 5 6

n=10 n=126 n=79 n=37 n=19 n=77

Efficacy of HBV Agents After One Year of Therapy: HBsAg Loss

Data from 2012 EASL HBV Management Guidelines

100

80

60

40

20

0

HB

sAg

Loss

(% p

atie

nts

at 1

yea

r)

Tenofovir Entecavir Telbivudine Lamivudine Adefovir PEG-IFN-2a

HBeAg+

HBeAg–

Nucleoside analog therapy has little effect on HBsAg levels, HBsAg loss and depletion of cccDNA

Emergence of resistance is a potential problem with long term nucleoside analog therapy

Long term adverse events may occur with continued use of nucleoside analogs

Pitfalls of Current Therapy

Absence of plasma HBV DNA after stopping antiviral therapy

Loss of HBsAg with or without HBsAg seroconversion

Goals for Eradication

Target the Virus Target the Hostand/or

• Viral proteins or nucleic acids• Host proteins necessary for viral

replication• Innate or adaptive immune system

Novel Strategies to Eradicate HBV

Target the Virus

• Viral proteins or nucleic acids


Entry of HBVinto cell

HBV Life Cycle, Potential Targets

Repair

Transcription

TranslationCore assembly

and RNA packaging

Recycling

HBV

Core particleminus strand

synthesis

Core particleplus strandsynthesis

Vesicular transport

to cellmembrane

cccDNA

HBsAg

HBeAg


Targeting HBV Entry

Repair

Transcription


and RNA packaging

Recycling

HBV


synthesis


Vesicular transport

to cellmembrane

1

cccDNA

HBsAg

HBeAg

Inhibition of Viral Entry: Myrcludex B

Myrcludex B prevents de novo infection preclinicallyKey Issues: Will it have an impact on chronic infection, or HBsAg loss?

uPA-SCID HBV Mice

Lütgehetmann M, et al. Hepatology 2012; 55:685-694

7

6

5

4Log

Vire

mia

[cop

ies/

ml]

HBV HBVControl Treated

50

40

30

20

10

0

HB

sAg

(IU/m

L)

Control Treated

LLoDLLoD

Myr2 108 163 389

HBVpreS/2-48myr IC50: ~8 nM2v 2 48


Targeting cccDNA

Repair

Transcription


and RNA packaging

Recycling

HBV


synthesis


Vesicular transport

to cellmembrane

2cccDNA

HBsAg

HBeAg

Depleting or Inactivating cccDNA

Key issues: – cccDNA = reservoir of infection

– Formation of new cccDNA can be blocked by inhibiting replication

– Existing cccDNA is not affecteddirectly by current therapies and hasa long half-life

– Is it possible to silence cccDNA epigenetically?

– Is it possible to destabilize cccDNA?

Belloni L. J. Clin Invest 2012; 122:529-537

Epigenetic Silencing of cccDNA by Interferon-alfa

cccDNALevels

HBV RNALevels

cccDNAAcylation

cccDNA “silenced”, not depletedPossible to identify other ways to “silence” cccDNA?Zinc finger motifs in Duck Hepatitis model

10

1.0

0.1

Log

cccD

NA

/hu-

cell

0.10

0.08

0.06

0.04

0.02

pgR

NA

/hu-

GA

PDH

1.0

0.8

0.6

0.4

0.2

preS

/S R

NA

/hu-

GA

PDH

Fold

indu

ctio

n

NTIFN-α

1.0

0.8

0.6

0.4

0.2 *

ZFP Decreases HBV Replication in Hep AD38 Cells

Weber et al, PLoS ONE 2014: 9(5): e97579.

TALENs• transcription activator-like effector nucleases

Chen et al, Molecular Therapy 2014; 22(2):303–311


Targeting Encapsidation

Repair

Transcription


and RNA packaging

Recycling

HBV


synthesis


Vesicular transport

to cellmembrane

3

cccDNA

HBsAg

HBeAg

BAY 41-4109*EC50 = 50 nM

*Deres, Science 2003; 299: 893-896; Weber et al. Antiviral Res, 2002; 54:69-78

HBV Capsid Inhibitors

Key Issue: Will capsid inhibitors impact HBsAg loss or only have antiviral activity like nucleosides?Phase 1 clinical trial is planned with HBV capsid inhibitor

8.0x1005

7.0x1005

6.0x1005

5.0x1005

4.0x1005

3.0x1005

2.0x1005

1.0x1005

0.0x1005

Treatment (14 days BID)

Placebo2x30mg/kg 3TC2x30mg/kg BAY 41-41092x15mg/kg BAY 41-41092x7.5mg/kg BAY 41-4109

** *

HB

V-D

NA

[gen

ome

copi

es/1

0ul p

lasm

a]


Targeting HBV Replication

Repair

Transcription


and RNA packaging

Recycling

HBV


synthesis


Vesicular transport

to cellmembrane

4

cccDNA

HBsAg

HBeAg


Targeting Envelopment and Secretion

Repair

Transcription


and RNA packaging

Recycling

HBV


synthesis


Vesicular transport

to cellmembrane

5

cccDNA

HBsAg

HBeAg

Inhibition of HBsAg Secretion

Dougherty AM et al. Antimicrob Agents Chemother, 2007; 51:4427-4437

Key Issues:– Will suppression of HBsAg antigenemia restore T cell responsiveness?

– Mechanism undefined, potential to inhibit host protein secretion?

HBF-0259Formula Weight = 364.21cLogP = 4.97

RI

CIF

NH

NN

N

N

CI

R2

76

54

12

3

100 23 42 618.0 4.0 2.0D

MSO HBF-0259 (µM)

Secr

eted

Density (%)

LM

AGP

Target the Host

• Host proteins necessary for viral replication

• Innate or adaptive immune system


Mechanisms of Persistence

GS-9620, an orally available agonist Selective for antiviral vs proinflammatory responsePreclinical studies: Reduces sAg, viral DNA in woodchucks & chimpanzeesPhase 1a (SAD) complete: Safety shown in healthy volunteers

N

N N

HN

O

NH2O

N

MYD88

IRF7 NFkB

IRF7 IRF7 NFkB

Pro-inflammatoryIFN, ISGs

TLR-7 Agonist for HBV

Lopatin U et al. Antivir Ther 2013; 18:409-418

-3

-2

-1

0

4 0

6 0

8 0

1 0 0

1 2 0

-2 8 7 1 4 2 5 3 1 4 5 5 7 7 9 9 3

D a y

Ch

ang

e in

Ser

um

HB

V D

NA

(log

IU/m

L)

Ch

ang

e in S

erum

HB

sAg

(% P

re-Tx)

Oral TLR7 Agonist GS-9620 Highlights Potential of Immunotherapy for Chronic HBV

Lanford et al. Gastroenterology 2013;144:1508-17.

1 mg/kg 2 mg/kg

HBV DNAHBsAg

n=3

Adaptive Immunity in Chronic Hepatitis B Infection

Effect of PD-1/L1 on Antiviral Immunity

Expansion of HBV-specific CD8 T Cell Response by Blocking PD-1/L1/2 Interaction In Vitro

Sherman AC et al. AIDS Res Hum Retr 2012

10

1

0.10

0.01

IFN

-γ s

ecre

ting

CD

8+T

Cel

ls (%

) PBMC (untreated)Anti-PD-1/L1/2

HBV CMV

*

Effect of anti-PD-1 or PD-L1 Antibodies in Cancer

June 28, 2012 No. 6Vol. 366

Safety, Activity, and Immune Correlates of Anti–PD-1 Antibody in Cancer

SL Topalian, M Sznol et al.

Safety and Activity of Anti–PD-L1 Antibody in Patients with Advanced Cancer

JR Brahmer, JM Wigginton et al.

• Blocks PD-1

• Acts on T cells

• More efficient blocking?

• More adverse events

• Risk benefit

• Blocks PD-L1

• Acts on APCs

• Less efficient blocking

• Less adverse events

• Risk benefit

PD-1 antibody PD-L1 antibody

Blocking PD-1/L1 to Enhance HBV Immunity

Chimeric Antigenic Receptors (CAR)

June CH et al Blood 2014

Therapeutic Vaccines

Li et al J Biotechnology 2012

Our goal is to achieve sustained suppression of HBV and HBsAg loss after cessation of therapy

Approaches to target virus include inhibition of viral entry, HBV antigen production, and elimination or silencing of cccDNA

Approaches to target host include non specific inhibition of immunoregulatory pathways and boosting of HBV specific immunity

Realistically, a combination approach may be necessary to achieve sustained virologic remission

Conclusions

HBV: What is in the Pipeline? - Virology...

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