Geoffrey DUSHEIKO

Nucleosides for HBeAg-positive chronic hepatitis B G Dusheiko Centre for Hepatology Royal Free and University College School of Medicine London UK

Nucleosides for HBeAg positive chronic hepatitis B Discuss –Efficacy –Safety –Utility –Resistance –outstanding questions

Nucleoside efficacy and pharmacology HBeAg positive chronic hepatitis B Nucleoside analogues well characterised –Results Ushered in new era of treatment for chronic hepatitis B Extensive response data acquired Can achieve desired end points of treatment Relative efficacy and response established

Treatment of HBeAg positive chronic hepatitis B: Goals and endpoints of treatment achieved with nucleosides –Suppression of HBV DNA Improve abnormal ALT Improve hepatic histology Slows development of fibrosis –Accelerates HBeAg seroconversion in some –HBeAg loss can lead to HBsAg loss –Prevent serious disease

HBV Treatment End points of Antiviral Response HBeAg Positive DNA decline/negativityALT declineHBeAg negAnti-HBeHBsAg neg Histology Improves Variable: RESISTANCE Variable T cell response

HBeAg Seroconversion after one year treatment PEG alpha2a Telbuvidine ETV-Study 022 LAM-Study 022 ADV-Marcellin 2003 LAM Consensus (11 References) LAM Consensus (RCTs † ) (4 References) PBO Consensus (5 References) PBO Consensus (RCTs) (4 References) % CI for Proportion With Seroconversion

Efficacy at Years 1 and 2: HBeAg(+) Patients (ITT Population) Week 52Week 104Week 52Week 104 n HBV DNA  from baseline (mean log 10 ) -6.5 * -5.7 † HBV DNA nondetectable by PCR (%)60 * 56 † 4039 ALT normalization [≤1 xULN] (%)7770 † 7562 HBeAg loss (%) HBeAg seroconversion (%) TelbivudineLamivudine

PEG alpha 2a: Effect HBV Genotype on HBeAg seroconversion Week 52 Genotype Cooksley G et al EASL 2005

Response Data acquired from nucleoside use Nature of response Predictors of response and durability of response Data from comparator arm studies Histological response Disease progression response Role of genotype Role of resistance and response Paediatric response

Lamivudine vs Telbuvidine:Serum HBV DNA Reductions to Week 52 Serum HBV DNA Reduction (Median Log 10 Reduction from Baseline) Weeks of Treatment Lamivudine LdT 400 LdT 600 LdT Lamivudine LdT Lamivudine Lai et al., Gastroenterology 2005

Serum HBV DNA, Mean Log 10 Change from Baseline 018 Trial: Telbivudine vs. Adefovir in HBeAg+ Chronic Hepatitis B Patients Serum HBV DNA Mean Log 10 Change From Baseline ± SE Adefovir (n=89) Telbivudine (n=44) p<0.01 PCR-negative at 6 months Telbivudine38.6% Adefovir12.4%

Tenofovir vs Adefovir in LAM- Resistant CHB van Bömmel F, et al. Hepatology. 2004;40: *P <.001 vs ADV Week 24Week 36Week Mean change in log 10 HBV DNA (PCR) Tenofovir 300 mg/day for weeks (n = 35) Adefovir 10 mg/day for weeks (n = 18) % HBV DNA < 400 copies/mL at Week 48  100% of tenofovir patients  44% of adefovir group -5.2* * * -2.8

Viral Load at Week 24: Telbivudine and Lamivudine HBeAg Positive

BaselineWeek 24Week 52 TelbivudineLamivudine Assay LLOQ 300 Copies/mL 67%52%25%38% Serum HBV DNA Log 10 Copies/mL BaselineWeek 24Week 52 Telbuvidine: Distribution of Patients antiviral response Baseline, Week 24 and Week 52: HBeAg-positive Patients Jia JD et al 2006 Chinese study

Entecavir: Distribution antiviral response HBeAg naïve Percent of Subjects* HBV DAN (Copies/ml) ≥ <300 Wk ETVLVD N= 81% 57%

HBeAg Seroconversion at 2 Years vs Antiviral Effect at Week 24 * Percent HBeAg seroconversion Serum HBV DNA level at Week 24 * HBeAg positive patients, telbuvidine and lamivudine groups.

Treatment with nucleosides Ease of use has raised questions –Indications for treatment –End points of treatment –Disease monitoring –PCR based hepatitis B DNA testing –Drug resistance

Lamivudine as a comparator arm: HBeAg positive LamPEG IFN (2a) Lam 100Entecavir 0.5 mg LamLdT 600, pooled n Histol Resp*38%34%62 %72 % Log 10 decline DNA < 400*40 (5) %25 (14) %38 %69 %32 %61 % HBeAg seroconversion 20 (19) %27 (32) %18 %21 %22 %31 % Resistance*27%ND18%2%15.8 %4.5 % *< 200 c/ml LdT, Resistance various defn, Histol response various LdT See also Lai et al AASLD www. aasld.org #72484

Lamivudine (nucleosides) predictors of response High baseline ALT Higher HAI score Early viral suppression Lack of resistance Cirrhosis ? (High DNA) (Genotype) Need predictors of durability

Weeks after start of lamivudine therapy HBeAg seroconversion (%) n:7 n:17 n:11 ALT  2xULN ALT 2~5xULN ALT > 5xULN n:29 n:53 n:43 n:89 n: Lamivudine: HBeAg seroconversion relative to baseline serum ALT: Asia placebo 25mg/day 100mg/day Chien R-N et al Hepatology 30:

Percent HBeAg Seroconversion Over 4 Years Lamivudine With or Without resistance Leung et al

Response Percent - - HBeAg Loss by Pre-Treatment ALT and ethnic origin in Patients treated with Lamivudine Perrillo et al.,Hepatol 2002;36:186

Disease modification with lamivudine therapy: Time to Disease Progression by YMDD Status Liaw et al, NEJM 2004

Nucleosides and immune therapy As part of therapeutic vaccination Interrupted therapy Pulsed dendritic cell vaccination Prednisolone withdrawal and Lamivudine Combination with interferon –More profound suppression –Less LAM resistance Furukawa 2004; Sprengers 2003; Liaw et al. Gotto et al

Integral role liver transplantation –Combination of LAM and HBIG –In decompensated disease –anti-HBc donors Fulminant hepatitis Prophylactic chemotherapy Extrahepatic disease Immunosuppressed patients HIV co-infected patients In pregnancy Utility of lamivudine (nucleosides)

Lamivudine in Decompensated Cirrhosis Yao FY et al. Hepatology 2001;34: Consecutive UCSF Pts Compared to 23 Historical Controls Cumulative probability of survival without liver transplantation P<0.001

Safety of nucleosides Safe agents, with infrequent monitoring Rare reports of –mitochondrial toxicity –renal impairment –peripheral neuropathy –CPK elevations and myositis Use in cirrhosis and decompensated cirrhosis Flares with initiation, withdrawal and resistance

Hepatitis Flares with (+) or without (-) lamivudine resistance Lok et al Gastroenterology 125:

Hepatitis Flares with or without detectable lamivudine resistance

Clinical course after breakthrough Complex –Hepatitis common, not always severe Generally experience worsening of liver disease Role of genotypes Role of mutations Core promoter mutations and outcome –(A1762T/G1764A) Lok 2003; Dienstag 2003; Ide 2005

Resistance to nucleoside analogues Results offset by resistance Use of first line monotherapies restricted Avoid sequential therapy Appropriate salvage interventions Predictors resistance being identified Combination therapy –Form backbone of therapy –Expanding number of agents –Grow experience Characterisation pol resistance mutations –Mutational pathways –New technologies

Predictors of resistance  Duration of treatment  Lamivudine monotherapy  Correlation with early suppression  HBeAg status vs anti-HBe?  Core promoter variants  Subtype adw?  Lower baseline ALT  Higher baseline HBV DNA  Immunosuppression  Body mass index

Viral Resistance at 2 Years vs Antiviral Effect at Week 24 Serum HBV DNA level at Week 24 HBeAg(+)HBeAg(-) Percent withresistance n=

Telbuvidine Viral Resistance at 2 Years vs Antiviral Effect at Week n= Percent withresistance HBeAg positive

“Low resistance nucleosides” Entecavir (naïve)  152 treated for three years (from 673 naïve)  3 developed point mutations conferring ETV resistance  ?? cumulative incidence 1.1 % –Prototypical substitution Position S202G confers entecavir resistance in the setting of L180 - M204 - S202G Tenofovir?

Drug Duration Yielding Identical Costs

HBV Pol Resistance Mutations LMV Resistance rtL80V/I rtV173L/rtL180M rtM204V/I/S ADV ResistancertV84MrtA181T/V rtQ215S rtN236T ETV Resistance rtS184G rtS202IrtM250V L-dT Resistance rtM204I ADV + LMV Resistance rtL180M + rtA181V TDF Resistance rtA194T ABC Resistance rtH234Y 845 a.a. Terminal Protein Spacer POL/RT RNaseH ABCED (rt1)692 (rt 344) YMDD F__V__LLAQ__ I(G) II(F)

Combination therapies with nucleosides Naïve patients –Lamivudine and PEG interferon –Lamivudine and famciclovir –Lamivudine and adefovir –(Lamivudine and telbuvidine) –Lamivudine and tenofovir –FTC and tenofovir Ideal complications in the offing –Two agents which do not share cross resistance Prospective trials required with low resistance drugs

Double resistant Lamivudine and Adefovir? ADV LAM mutant strain phenotype L180M, M204V, N236T Replicated less efficiently in transient transfection assay Drug susceptibility: Reduced susceptibility to ADV and LAM Sequential use of nucleos(t)ide analogs will lead to the selection multiple drug resistant strains Brunelle et al Hepatology 41:1391, 2005

Nucleosides HBeAg positive Advantages Effective, safe suppression of HBV replication HBeAg seroconversion increments –2 years = that of PEG IFN one year –HBsAg loss can follow Can be used for long term treatment Oral once daily dosing vs injection Extended use in spectrum of disease –Disease modifying agents Few side effects

Nucleosides for HBeAg positive chronic hepatitis Results offset by resistance Use of first line monotherapy restricted Better use is indicated We should investigate potential of (maintenance) combination therapy Can agents with < 5% resistance at 3 years be utilised as monotherapies? –(HBeAg negative)

Optimal use Maximizing maintaining HBV suppression a key milestone for improvement Better early viral suppression improves therapeutic outcomes in several reports Previous results with lamivudine, adefovir and tenofovir suggest early viral suppression (at 6 or 12 months) predicts the lowest resistance subsequently May help patient management

HBeAg Positive Hepatitis: Nucleoside therapy Unanswered Questions Duration of therapy before and after HBeAg loss Long term durability off therapy (virological and histological response) Effect of therapy on long term outcome How best to monitor for drug resistance Risk factors for resistance Role of HBsAg genotype – (on response) and drug resistance

Pegylated interferon therapy HBeAg positive chronic hepatitis B Weak immunomodulatory effect Net effect highest one year seroconversion rates. Permits first use in HBeAg positive –Need early prediction of failed treatment –Prolonged use difficult. Pre-treatment predictive factors? –ALT, genotype, age? No role in fulminant hepatitis, cautious use in cirrhosis, problematic in decompensated cirrhosis Frequent side effects and need for close monitoring Patient choices? Additive use with nucleosides not fully explored.