# Presentation: 121292

## Hepatitis B

**Jay H. Hoofnagle, M.D.**
**Division of Digestive Diseases **
**and Nutrition**
**National Institute of Diabetes and Digestive and Kidney Diseases**
**National Institutes of Health**

***FDA Advisory Panel Meeting: August 7, 2002***

## Hepatitis B

**HBV, small double stranded DNA virus**
**Hepadnaviridae**
**Infection restricted to humans and higher apes**
**High levels in blood (10****2 ****to 10****10**** copies/ml)**
**Causes both acute and chronic hepatitis**
**Parenteral, sexual and maternal-infant spread **
**Marked geographic variation in incidence**
**Common in Asia & Africa, uncommon in the United States and Western Europe**

## Hepatitis B Virus

**HBsAg**

**HBsAg**

**HBsAg**

**HBcAg**

**Dane Particle**

**Tubule**

**Sphere**

**HBeAg**

## Slide 4

## 2.1kb RNA

**2.1kb RNA**

**2.4kb RNA**

**3.5kb RNA**

**0.7kb RNA**

**Pre-S1**

**Pre-S2**

**ORF-S**

**ORF-P**

**ORF-X**

**ORF-C**

**DR1**

**5’**

**5’**

**+strand**

**-strand**

**Pre-C**

**DR2**

**Hepatitis B Virus RNAs**

## Hepatitis B Viral Genome

**Circular, partially doubled-stranded DNA  **
**Four open reading frames **
**HBsAg (pre-S1, pre-S2 and S)**
**HBcAg (pre-core & core) **
**Polymerase (multifunctional)**
**HBxAg (transactivating factor)**
**Replicates largely in liver**
**Through RNA intermediate and reverse transcription**

## Infectious cycle of hepatitis B virus 

**degradation**
**- antigen-specific**
**- non-specific**

**Y**

**Y**

**Y**

**Y**

**Y**

**Y**

**Y**

**Y**

**cell death**

***Virus****** ***- half-life:	     1-2 days
- 	-production: 	             1011-1013/day
- 	mutation rate:      1-3 x 10-5/site/yr

**Zeuzem et al: 2000**

## Hepatitis B Virus Mutants

**Variations in nucleotide sequence in one of the HBV genes can result in change in the virological and, in some cases, clinical features of the infection.**
**S gene****: vaccine or HBIG escape mutants**
**C gene****: can affect disease severity or serological and clinical manifestations**
**P gene****: can effect replicative efficiency and resistance to antiviral therapy**

## Hepatitis B Core Antigen Mutants

***Nucleocapsid region: Pre-core and Core***
***Pre-core:***** ****May result in inability to produce HBeAg.  HBeAg-negative mutants.***** *****Most frequently, G********A at *****nt 1896*****.**
***Core:  *****Substitutions in core region are frequent among pts with severe disease or resistance to interferon, in areas of major B cell and T cell epitopes, thus important  in T cell cytotoxicity and viral clearance**

## HBeAg-negative Variants

***G************A***** at *****nt 1896***** creates a stop codon in the pre-core region that therefore blocks the synthesis of HBeAg.**
***nt 1896***** is in the highly structured stem-loop ******** encapsidation signal region of HBV RNA and base-pairs with *****nt 1858****** ***
**If *****nt 1858***** is a *****T***** (*****ayw, adr*****, some *****adw*****), stem loop of ******** ****is maintained by either *****G***** or *****A*****; if it is a *****C***** (*****adw*****), stem loop is disrupted by *****A *****and replication is stopped*****.***
***Thus HBeAg-negative variants are more common with genotypes B, C and D than genotype A***

## Outcome of Hepatitis B Virus Infection

**Acute Hepatitis B**

**Asymptomatic subclinical infection**

**Fulminant Hepatitis **

**Chronic Hepatitis B**

**Inactive Carrier State**

**Cirrhosis **

**Liver Cancer**

- ?

**65%**

**35%**

**<1%**

**5%**

**30%**

**50%**

## Typical Acute Hepatitis B

**Typical Acute Hepatitis B**

**ALT**

**HBsAg**

**HBeAg**

**HBV DNA**

**Normal **

**Months After Exposure**

**ALT and HBV DNA **
**IU/L and million copies/ml**

**Symptoms**

## Typical Chronic Hepatitis B

**ALT**

**HBsAg**

**HBeAg**

**HBV DNA**

**Normal **

**Months After Exposure**

**ALT and HBV DNA **
**IU/L or million copies/ml**

## Chronic Hepatitis B: Transition to Inactive Carrier State

**Chronic Hepatitis B: ****Transition to Inactive Carrier State**

**ALT**

**``****	**

**HBsAg**

**HBeAg**

**HBV DNA**

**Normal **

**Months After Exposure**

**ALT and HBV DNA **
**IU/L and million copies/ml**

**Anti-HBe**

## Evolution of HBeAg Negative Mutant 

**ALT**

**HBsAg**

**HBV DNA**

**Normal ALT levels**

**Months **

**ALT and HBV DNA**
**IU/L and million copies/ml**

**Anti-HBe**

**HBeAg**

## Chronic Hepatitis B: Three Clinical Forms: 

**HBeAg Positive Chronic Hepatitis B  **
**	*****HBeAg, raised ALT, HBV DNA in serum and chronic hepatitis on biopsy***
**HBeAg Negative Chronic Hepatitis B   **
**	*****Anti-HBe, raised ALT and HBV DNA in serum, chronic hepatitis on biopsy***
**Inactive HBsAg Carrier State  **
**	*****Anti-HBe, normal ALT & no HBV DNA, minimal nonspecific changes on biopsy ***

## Chronic Hepatitis B: Clinical Forms: HBV DNA levels

**HBeAg Positive Chronic Hepatitis B  **
**	****	****10****7 ****to 10****11**** copies per ml**
**HBeAg Negative Chronic Hepatitis B   **
**	****	****10****4 ****to 10****8**** copies per ml**
**Inactive HBsAg Carrier State  **
**	****	****< 10****1 ****to 10****4**** copies per ml***** ***

## HBV DNA Detection

**350**

**3.5**

**.035**

**Log****10**** copies/mL**

** ****pg/mL**

**8**

**6**

**4**

**2**

**10**

**35,000**

**Dynamic Range of Detection of HBV DNA: 5 Assays**

**HBV DNA Detection**

**.0035**

## Genotypes of Hepatitis B Virus

**  ****A****	****	*****adw*****, *****adw*****2, *****ayw*****1****	****US, Northern Europe, Africa**
**  ****B****	****	*****adw*****2, *****ayw*****1****	****	****China, Indonesia, Vietnam**
**  ****C****	****	****adr, *****ayr******	****** *****	****China, Korea, Japan, Vietnam**
**  ****D****	****	*****ayw*****2, *****ayw*****3****	****	****Mediterranian, Middle East, India**
**  ****E****	****	*****ayw*****4****	****	****	****West Africa**
**  ****F****	****	*****adw*****4****	****	****	****Polynesia, US (rare)**
**  ****G****	****	****	****	****	****Europe, US (rare)  ****	****	****	**

**Type****	****Subtype****	****	****Geographical Distribution**

## Acute Hepatitis BSentinel County Study: 1982-98

**Currently, HBV causes 34% of viral hepatitis**
**Decline in incidence by 76% between 1987-98**
**20% hospitalized, 1% fatal**
**Gradual rise in median age (27 to 32 yrs)**
**More common in men than women**
**African-Americans > Hispanic whites > whites**
**Current proportions with risk factors**
**Injection drug use:       14%**
**Men who has sex with men:   15%**
**Heterosexual activity:    40%**
**Occupational exposure:  2%  **

***Goldstein et al: 2002***

## Year

**Vaccine**
**licensed**

**HBsAg  screening**
**of pregnant women**

**Routine infant**
**immunization**

**OSHA Rule**

**Routine adolescent immunization**

**Decline in **
**MSM & HCW**

**Decline in injecting drug users**

**Decline in high-risk**
**heterosexuals**

**Year**

**Infections per 100,000**

**Acute Hepatitis B Incidence in the U.S.: 1978-1998**

***Alter et al: CDC***

## Chronic Liver Disease: United States 1999

**Hepatitis C  57%**

**Alcohol 25%**

**Hepatitis B**

**Other**

**NASH 10%**

**Bell et al 2001**

**Hepatitis B accounted for only 4.4% of newly-diagnosed chronic liver disease**

## Chronic Hepatitis BLong-Term Complications

**Cirrhosis**
**Hepatocellular carcinoma**
**Glomerulonephritis**
**Polyarteritis Nodosa**

## Chronic Hepatitis BHistology

**Necroinflammatory Changes (****Grade****)**
**Periportal inflammation and necrosis (piecemeal necrosis, interface hepatitis)**
**Lobular inflammation and single cell necrosis**
**Portal inflammation**
**Fibrosis (****Stage****)**
**Portal**
**Septa formation**
**Bridging fibrosis**
**Cirrhosis**

## Chronic Hepatitis BHistology Scoring Systems

**Histology Activity Index (Knodell) :**
**Periportal necrosis & inflammation (0-10)**
**Lobular necrosis & inflammation (0-4)**
**Portal inflammation (0-4)**
**Fibrosis**
**None = 0 **
**Portal fibrosis = 1**
**Bridging fibrosis = 3**
**Cirrhosis = 4**

## Chronic Hepatitis BHistology Scoring Systems

**Histology Activity Index (Ishak) :**
**Periportal necrosis & inflammation (0-4)**
**Bridging necrosis (0-6)**
**Lobular necrosis & inflammation (0-4)**
**Portal inflammation (0-4)**
**Fibrosis**
**None = 0 **
**Portal fibrosis = 1 or 2**
**Bridging fibrosis = 3 or 4**
**Cirrhosis = 5 or 6**

## Therapy of Hepatitis B

## Chronic Hepatitis BGoals of Therapy

**Improve symptoms and quality of life**
**Decrease infectivity**
**Prevent progression of disease**
**Hepatic Decompensation **
**Death from liver disease**
***What surrogate end-points ***
***correlate with these outcomes ?***

## Therapy of Chronic Hepatitis B: Major Issues 

**What are appropriate end-points?  **
**Are they the same for different forms of HBV?**
**Loss of HBeAg**
**Loss of HBsAg**
**Loss of HBV DNA (fall below 10****5 ****copies/ml)**
**Normalization of ALT**
**Improvement in histology**
** ****What amount of follow up is appropriate in assessing benefit of therapy?**

## Definition of Responses to  Therapy in Chronic Hepatitis B

** ****Type:**
**Virological:     Loss of HBeAg and/or HBV DNA **
**Biochemical:  Normal ALT**
**Histological:   Improvement in histology scores**
**Complete:       All of above & loss of HBsAg**
** ****Timing:**
**Initial: within first 6 mo of therapy**
**End-of-therapy: when therapy is stopped**
**Sustained: 6 or 12 mo after stopping**
**Maintained: present while continuing therapy**

## Virological Response in Chronic Hepatitis B

**Loss of HBeAg and fall of HBV DNA levels to below 10****5 ****copies/mL**
**Occurs in 25-48% of patients given a 4-5 month course of alpha interferon**
**Occurs in 20-32% of patients given a 12 month course of lamivudine**
**Occurs in 8-12% of patients on no therapy**
**Is this response durable and does it result in long-term improvement in disease and lack of progression to cirrhosis and HCC?**

## Virological Response in Chronic Hepatitis B

**Loss of HBeAg cannot be used as an endpoint in patients with HBeAg-negative disease **
**Generally rely upon decrease in HBV DNA to below 10****5**** copies/ml**
**HBV DNA levels, however, can fluctuate widely, and with nucleoside therapy will rapidly return to baseline when treatment is stopped.**
**How durable is decrease in HBV DNA without other changes in viral status?**

## Virological Response in Chronic Hepatitis B

**Loss of HBsAg and development of anti-HBs**
**Occurs in 8% of patients given a 4-5 month course of alpha interferon**
**Occurs in 1-2% of patients given a 12 month course of lamivudine**
**Occurs in <1% of patients on no therapy**
**Extremely rare in treatment trials of HBeAg-negative chronic hepatitis B**
**This response is durable and associated with resolution of liver disease**

## Biochemical Response in Chronic Hepatitis B

**Fall of ALT levels into the Normal Range**
**Often accompanies loss of HBeAg or decrease in HBV DNA to below 10****5**** copies/mL**
**Not durable unless the decrease in HBV DNA is durable.**
**Surrogate, indirect marker for decrease in necroinflammatory disease  **

## Histological Response in Chronic Hepatitis B

**Improvements in Histology**
**Used in virtually all studies of antiviral therapy**
**Typically, improvement is called a **_**>**_** 2 point improvement in HAI score (0-22) compared to baseline**
**However, necroinflammatory scores can change rapidly and improve and worsen**
**Fibrosis scores represent best evidence for progression of disease and are unlikely to improve with treatment**

## Alpha Interferon 

**Human cytokine made by lymphocytes in response to viral infection**
**Acts through cell-surface receptors**
**Activates Jak/Stat system**
**Induces transcription of proteins with antiviral activity (2-5 OAS, PKR, eIF2)**
**Recombinant human alpha interferon**
**Pegylated forms now available**

## Chronic Hepatitis BLong-term Response to Interferon

**Chronic Hepatitis B*****Long-term Response to Interferon***

**HBeAg**

**HBsAg**

**Anti-HBe**

**Anti-HBs**

**Alpha Interferon**

**ALT**

**Months After Start of Therapy**

**Patient A**

**HBV DNA (dot blot)**

## Chronic Hepatitis BResponse to Interferon & Relapse

**Chronic Hepatitis B*****Response to Interferon & Relapse***

**HBeAg**

**HBsAg**

**Alpha Interferon**

**ALT**

**Months After Start of Therapy**

**HBeAg**

**Anti-HBe**

**Patient B**

## HBeAg-Negative Chronic Hepatitis BResponse to Interferon and Relapse

**HBeAg-Negative Chronic Hepatitis B*****Response to Interferon and Relapse***

**HBsAg**

**Alpha Interferon**

**ALT**

**HBV DNA**

**Months After Start of Therapy**

**Patient C**

**Anti-HBe**

**+**

**+**

**+**

**+**

**-**

**-**

**-**

## Interferon for Chronic Hepatitis B: Problems

**Effective in only 1/3****rd**** of cases**
**Expensive**
**Side effects are common and can be severe**
**Not appropriate for many categories of pts:**
**Immune suppressed**
**Renal failure or dialysis**
**Solid organ transplant**
**Decompensated liver disease**

## Lamivudine 

**Negative enantiomer of 3-thiacytidine**
**Both an unnatural nucleoside and chain terminator **
**Highly active against HBV in vitro**
**Dose: 100 mg, once daily by mouth**
**Approved for use in chronic hepatitis B as one year course of therapy**
**Continuous, long-term use is common but must be considered experimental**

## Lamivudine TherapyMaintained Response 

**Lamivudine Therapy*****Maintained Response***** **

**HBV DNA**

**ALT**

**10****2**

**10****4**

**10****6**

**10****8**

**HBV DNA Levels**

**Therapy with Lamivudine (100 mg/d)**

**HAI Scores:**
**Pre:  ****14**
**Yr 1:  ****4**
**Yr 4:  ****1**

**HBeAg**

**HBsAg**

**Patient B**

## HBeAg-Negative Chronic Hepatitis B

**HBeAg-Negative Chronic Hepatitis B**

**HBsAg and Anti-HBe**

**Lamivudine**

**ALT**

**Months After Start of Therapy**

**Patient C**

**HAI = 4**
**200 copies/ml**

**HAI = 13**
**53.1 million copies/ml**

**HAI = 1**
**<100 copies/ml**

**Liver Biopsy**
**HBV DNA**

## Lamivudine Therapy:Viral Resistance

**Lamivudine Therapy:*****Viral Resistance***

**HBV DNA**

**ALT**

**10****2**

**10****4**

**10****6**

**10****8**

**HBV DNA Levels**

**Normal**

**Therapy with Lamivudine (100 mg)**

**HAI Scores:**
**Pre:  ****14**
**Yr 1: ****10**
**Yr 4:**** 17 (Cirrhosis)**

***wt***

***YVDD ***

**10****10**

**Patient D**

## Lamivudine for Chronic Hepatitis BHistology Activity Index Scores

**9.8**

**9.9**

**2.5**

**8.4**

**1.3**

**7.1**

**13**

**9**

**13**

**4**

**9**

**9**

**Total HAI Scores (0 to 18)**

- Lamivudine for Chronic Hepatitis B*Histology Activity Index Scores*

## Lamivudine for Chronic Hepatitis B: Fibrosis Scores

**4.2**

**2.9**

**1.3**

**3.9**

**3.3**

**4.3**

**13**

**13**

**4**

**9**

**Fibrosis Score (0 to 6)**

**Lamivudine for Chronic Hepatitis B: *****Fibrosis Scores***

**9**

**9**

## Lamivudine TherapyLate Relapse 

**Lamivudine Therapy*****Late Relapse***** **

**HBV DNA**

**ALT**

**10****2**

**10****4**

**10****6**

**10****8**

**HBV DNA Levels**

**Therapy with Lamivudine (100 mg/d)**

**HAI Scores:**
**Pre:  ****14**
**Yr 1:  ****4**
**Yr 4:  ****1**

**HBeAg**

**HBsAg**

**Patient B**

## 85%

**85%**

**50%**

## Lamivudine 

**The major shortcoming of long-term  lamivudine therapy for hepatitis B is  emergence of lamivudine resistance**
**Occurs in 20%-30% of patients per yr, approaching 90% by 5 yrs**
**Loss of HBsAg, but not loss of HBeAg, appears to reliably predict long-term benefit & ability to stop lamivudine**
**Future studies should focus on combinations that might prevent resistance**

## Optimal Therapy of Hepatitis B?

**Monotherapy or combination therapy?**
**For a defined period (48 wks) or continuous?**
**For all pts or only those with mod-severe disease?**
**If monotherapy, which agent?**
**If combination, which combination?**
**Standard interferon and lamivudine**
**Pegylated interferon and lamivudine**
**Lamivudine and adefovir**
**Lamivudine and entecavir**

## Management of Hepatitis B

**Initial evaluation:  Routine liver tests, HBsAg, HBeAg & anti-HBe, HBV DNA, anti-HDV, abdominal US**
**If ALT elevated & HBV DNA present:   liver biopsy and assess for therapy**
**Reserve therapy for patients with significant underlying liver disease**
**Therapy? **

**Lok, Heathcote & Hoofnagle: 2001**

## Therapy of Chronic Hepatitis B: Future Directions 

**Focus must be on combination therapy**
**Long term outcomes with histological verification of long-term benefit**
**Loss of HBsAg might be a gold standard**
**Appropriate directions:**
**Combinations of alpha interferon & lamivudine**
**Nucleoside combinations without cross-reactive resistance (lamivudine & adefovir or entecavir)**
**Novel approaches: immunological or molecular**