HBV resistance and immune escape mutants

1. HBV resistance and immune escape mutants Anders Boyd, MPH, PhD Inserm UMR_S1136 iPLESP 3rd International HIV/Viral Hepatitis Co-infection Meeting

2. Antiviral resistance mutants • What are the selective pressures involved? • What are the specific mutations observed during resistance? • What are the rates of developing resistance mutations during antiviral therapy? • What are the clinical implications?

3. Developing drug resistance Richman DD. Hepatology, 2000; Zoulim F & Locarnini S. Gastroentrology, 2009.

4. Developing drug resistance • Types of mutations on the polymerase gene conferring resistance to NAs rt344 rt1 II(F) D A I(G) C E B Zoulim F & Locarnini S, Gastroenterology, 2009; Gish R et al., Lancet Inf Dis, 2012.

5. Developing drug resistance • Incidence of resistance among treatment-naïve HBV mono-infected patients *Only two-year data are available. Gish R et al., Lancet Inf Dis, 2012.

6. LAM-resistance in co-infection • Rates of developing LAM-resistance in treated HIV-HBV co-infected patients - Almost all HBV highlyviremic patients - Two-thirds HBeAg+ - Sexual transmission route % with resistance Duration of LAM (years) Benhamou Y et al., Hepatology, 1999; Matthews GV et al., AIDS, 2006.

7. LAM-resistance in co-infection • Rates of developing LAM-resistance in treated HIV-HBV co-infected patients - LAM-treated patients from Ghana - Lowviremic - One-quarter HBeAg+ LAM resistanceis not common in individualswithlow HBV-DNA (<20,000 IU/mL) Low risk of LAM-resistance when HBV-DNA viral loads are low. Stockdale AJ et al., Clin Infect Dis, 2015; Kim HN et al., J Viral Hepatitis, 2011; Day SL et al., PLoS One, 2013; Thio CL et al., AIDS, 2015; Boyd A et al., Antiviral Ther, 2015.

8. TDF-persistence in co-infection • Virological response among HIV-HBV co-infected patients undergoing TDF-containing ART A small % continues to have detectable HBV-DNA after extended therapy Price H et al., PLoS One2013.

9. TDF-persistence in co-infection • Virological persistence among TDF-treated HIV-HBV co-infected patients (N=111) Undetectable HBV-VL (<60 IU/mL) at end of follow-up (n=96) Detectable HBV-VL (≥60 IU/mL) at end of follow-up (n=15) Stabilized virological response (n=86) Low-level persistent viremia 60-2000 IU/mL (n=11) Transient persistent viremia (n=10) High-level persistent viremia >2000 IU/mL (n=4) Boyd A et al., Hepatology, 2014; Matthews GV et al., Clin Inf Dis, 2013.

10. TDF-persistence in co-infection • HBV mutations in transientpersistence Boyd A et al., Hepatology, 2014.

11. TDF-persistence in co-infection • HBV mutations in low- or high-levelpersistence Boyd A et al., Hepatology, 2014.

12. TDF-persistence in co-infection • Quasi-species diversity during persistence *Any detectable HBV DNA after six months of TDF. • Longitudinal ultradeep pyrosequencing results available in 5 patients: • Large changes in HBV viral diversity • Three with notable changes in phylogenetic trees AudsleyJ et al., AIDS, 2016.

13. Clinical implications of resistance • Liver-related end-points associated with antiviral resistance Lok AS et al., Gastroenterol, 2003; Bessesen M et al., Clin Infect Dis. 1999; Drake A et al., Clin Infect Dis, 2004; Stockdale AJ et al., Clin Infect Dis, 2015; Papatheodoridis GV et al., J Hepatol, 2015; Chen CF et al., Gastroenterol, 2011; Boyd A et al., Hepatology, 2014.

14. Immune escape mutants • What are the selective pressures involved? • What are the specific mutations observed? • What are the rates of developing immune escape mutations? • What is the public health impact?

15. Developing immune escape mutants • Genetic variability – S-gene mutations Antiviral-associated selective pressure (LAM/LdT) Immune-associatedselective pressures (HBIg prophylaxis, etc.) • These mutations are associated with: • Diminished antigenicity towards HBsAg1 • Vaccine escape2 • False-negative serological tests (ELISA) 1Torresi J, J ClinVirol 2002. 2Kamili S et al., Hepatology,2009 3Zoulim F & Locarnini S, Gastroenterology, 2009.

16. 70 70 60 60 50 50 40 Point Prevalence (%) 40 30 30 20 20 10 10 0 0 0 12 24 36 0 12 24 36 Visit (month) Visit (month) rtM204I rtM204V rtL180M+rtM204V/I rtV173L+rtM180L+rtM204V/I sP120S/T sG145A/K/R Total Total Developing immune escape mutants Antiviral-associated Immune-associated • Incidence of immune escape mutants ↑ cumulative LAM-exposure ↓ cumulative TDF-exposure ↓ cumulative TDF-exposure Lacombe K et al., Hepatology, 2013.

17. Public health consequences • Compromises HBsAg-detection 1Coleman PF, EmegInf Dis, 2006;2Scheiblauer H et al., Vox Sang, 2010; Servant-Delmas A et al., J Clin Virol, 2012; 3Hirzel C et al., J Clin Virol, 2015; Bottero J et al., J Hepatol, 2013;4Pollicino T et al., Hepatology, 2012; 5Verheyen J et al., J Clin Virol, 2012.

18. Public health consequences • Jeopardize vaccination programs • Epidemiological study in Taiwan: • Most HBsAg+ infections in the vaccinated cohort were due to maternal-child transmission. • 7/16 (44%) in vaccinated cohort with OBI harbored S-gene mutants on the “a” determinant. 1Ni YH et al., J Hepatol, 2012; Hsu HY et al., Hepatology, 2015; Whittle HC et al., Lancet, 1995; Amponsah-Dacosta E et al., J Clin Virol, 2015.

19. Public health consequences • Becoming an issue for non-vaccinated individuals? N=62 patients with acute HBV infection in Italy, 2000-2010 45.9% did not develop anti-HBs antibodies ↑genetic variability at HBsAga.a. 130, 133, 157 • Other genotypic findings: • 53.2% harbored a viral population with ≥1 immune-escape mutation • 8.1% had ≥1 detectable drug resistance mutation Aragri M et al., J Inf Dis, 2016.

20. Conclusions • Antiviral resistance mutations • LAM-resistance is a major problem (especially for patients with high HBV viral loads) • TDF-persistence occurs at 10%, is it a problem? • Immune escape mutations • These mutations increase with uncontrolled infection • Could remain a diagnostic issue • Public health impact seems limited for now, future projections are needed

21. Acknowledgements