Reduction of covalently closed circular DNA with long-term nucleos(t)ide analogue treatment in chronic hepatitis B.

BACKGROUND AND AIMS: Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA), a mini-chromosome essential for HBV replication, is supposed to be resistant to nucleos(t)ide analogue treatment. We investigated the effect of long-term nucleos(t)ide analogue treatment on cccDNA. METHODS: Among 129 patients who had been enrolled in previous international nucleos(t)ide analogue clinical trials and had liver biopsies at baseline and one year after treatment, we recruited 43 patients on long-term continuous treatment for 72 to 145months for a third liver biopsy. Serum HBV DNA, hepatitis B surface antigen (HBsAg) levels, total intrahepatic HBV DNA (ihHBV DNA), cccDNA, HBV pregenomic RNA (pgRNA) as well as histologic changes were examined. RESULTS: At the time of the third biopsy, serum HBV DNA levels were undetectable in all but one patient. The median levels of HBsAg, ihHBV DNA, and cccDNA were 2.88logIU/ml, 0.03copies/cell, and 0.01copies/cell, respectively. Compared to baseline levels, there was reduction of HBsAg levels by 0.54log (71.46%), ihHBV DNA levels by 2.81log (99.84%), and cccDNA levels by 2.94log (99.89%), with 49% having cccDNA levels below the detection limit. One patient had undetectable HBsAg. The median pgRNA level, measured only in the third biopsy, was 0.021copies/cell, with 40% of patients having undetectable pgRNA. CONCLUSIONS: Long-term nucleos(t)ide analogue treatment induced marked depletion of cccDNA in the majority of patients while serum HBsAg levels, though reduced, were detectable in all but one patient. Whether cccDNA depletion is sustained and associated with better patient outcome requires further study. LAY SUMMARY: It is generally presumed that a form of hepatitis B virus DNA, called covalently closed circular DNA (cccDNA), which hides inside the nuclei of liver cells of patients with chronic hepatitis B, cannot be reduced by antiviral treatment. The present study showed that with prolonged treatment (median period 126months), cccDNA can be markedly reduced, with 49% of liver biopsies having undetectable cccDNA. This suggests that viral replication capacity would be very low after prolonged antiviral treatment.

Effect of hepatitis B virus reverse transcriptase variations on entecavir treatment response.

BACKGROUND: Entecavir therapy often reduces hepatitis B virus (HBV) DNA to an undetectable level, but HBV DNA remain detectable in some patients. We investigated whether baseline HBV reverse transcriptase (rt) polymorphism and quasispecies complexity and diversity were associated with treatment response. METHODS: Pretreatment HBV DNA levels, HBV rt sequence, serology, and quasispecies complexity and diversity from 305 entecavir-treated patients were determined. These data were tested for their association with year 1 virological outcome, defined by optimal response (undetectable HBV DNA; lower limit of detection, ≤12 IU/mL) or partial response (detectable HBV DNA). RESULTS: Four rt variants were more frequently detected in the 64 partial responders than in the 241 optimal responders (all P < .05). Multivariate analysis revealed that high baseline HBV DNA level (P < .0001; odds ratio [OR], 2.32), HBV e antigen (HBeAg) positivity (P < .001; OR, 3.70), and rt124N (P = .002; OR, 3.06) were associated with a partial entecavir response. Compared with the optimal responders, the partial responders had a lower quasispecies complexity and diversity. CONCLUSIONS: Apart from the known factors (high baseline HBV DNA level and HBeAg positivity), a novel single nucleotide polymorphism (rt124N) and lower quasispecies complexity and diversity were associated with partial entecavir response at year 1.

HLA-DP and IL28B polymorphisms: influence of host genome on hepatitis B surface antigen seroclearance in chronic hepatitis B.

BACKGROUND: The roles of single-nucleotide polymorphisms (SNPs) at HLA-DP and IL28B loci on hepatitis B surface antigen (HBsAg) seroclearance in chronic hepatitis B (CHB) infection are unknown. METHODS: We compared the HLA-DP (rs3077, rs9277378, rs3128917) and IL28B (rs12979860, rs8099917) polymorphisms of 203 CHB patients achieving spontaneous HBsAg seroclearance with 203 age- and sex-matched CHB patients without HBsAg seroclearance (controls). RESULTS: The distribution of all 5 polymorphisms was in Hardy-Weinberg equilibrium. HLA-DP rs3077 was associated with HBsAg seroclearance in terms of allelic frequency (minor allele A vs major allele G, P = .035; odds ratio [OR], 0.699; 95% confidence interval [CI], .501-.976) and genotypic frequency (AA vs GG/GA, P = .014; OR, 0.295; 95% CI, .106-.822). Haplotype analysis of HLA-DP polymorphisms showed haplotype block GAT (rs3077/rs9277378/rs3128917) to be associated with HBsAg seroclearance (OR, 2.17; 95% CI, 1.06-4.45, P = .034). Influence of HLA-DP polymorphisms on HBsAg seroclearance was more pronounced in younger patients, with the OR for rs3077 minor allele A and haplotype block GAT being 0.560 and 2.68, respectively, among patients aged <50 years (P = .027 and P = .047, respectively). IL28B haplotype block CG (rs12979860/rs8099917) was associated with HBsAg seroclearance (OR, 10.5, P = .026). None of the 5 polymorphisms influenced anti-HBs positivity among patients achieving HBsAg seroclearance, or serum HBV DNA and HBsAg titers among controls (P > .05). CONCLUSIONS: Specific SNPs in HLA-DP and IL28B locus, through individual and haplotype analysis, were associated with a higher chance of HBsAg seroclearance in CHB infection. The associations were more prominent in patients with HBsAg seroclearance at a younger age.