Review article: long-term safety of oral anti-viral treatment for chronic hepatitis B

BACKGROUND

Safety profile of nucleos(t)ide analogues is an important issue in view of its widespread use for decades in patients with chronic hepatitis B (CHB).

AIM

To review and evaluate the latest evidence on the safety profiles of the six approved nucleoside analogues.

METHODS

Relevant articles related to nucleoside analogue safety were selected for review following extensive language- and date-unrestricted, electronic searches of the literature.

RESULTS

Nephrotoxicity has been well reported in patients receiving older generations of nucleotide analogues, namely adefovir dipivoxil and tenofovir disoproxil fumarate (TDF). Yet risks of renal failure and renal replacement therapy were similar in patients treated with nucleoside analogues versus nucleotide analogues in real-life setting. Bone toxicity is closely related to nucleoside analogue effect on renal proximal tubular and phosphaturia. Real-life data demonstrated increased risk of hip fracture in patients receiving adefovir but not TDF. The newly approved tenofovir alafenamide (TAF) has improved renal and bone safety profiles compared to TDF. Long-term use of nucleoside analogues eg entecavir does not increase the risk of other cancers. Muscular toxicity may be seen in telbivudine-treated patients so regular monitoring is advised. Peripheral neuropathy and lactic acidosis are rare adverse events. Latest international guidelines support the use of TDF, telbivudine and lamivudine during pregnancy; breastfeeding is not contraindicated during TDF therapy.

CONCLUSIONS

Long-term safety profile of nucleoside analogues is now better defined with more data from large real-life cohorts and clinical trials with long-term follow-up. The new nucleotide analogue, TAF is now available with favourable renal and bone safety profiles.

Review article: hepatitis B core-related antigen (HBcrAg): an emerging marker for chronic hepatitis B virus infection

BACKGROUND

Chronic hepatitis B (CHB) cannot be completely eradicated due to the presence of covalently closed circular DNA (cccDNA) in the nuclei of infected hepatocytes. While quantification of intrahepatic cccDNA requires liver biopsies, serological markers can be non-invasive alternatives to reflect intrahepatic viral replicative activity. Recently, hepatitis B core-related antigen (HBcrAg) has been advocated as a novel serum marker for disease monitoring and prognostication of CHB.

AIM

To examine the virological aspect and clinical application of HBcrAg with respect to the natural history and treatment of CHB.

METHODS

We reviewed all papers published in the PubMed journal list and abstracts from major international meetings that included the keyword "HBcrAg" or "hepatitis B core-related antigen" until March 2017. Selected studies were compared and summarised on the basis of existing theories, as well as the authors' experience.

RESULTS

HBcrAg exhibited good correlation with intrahepatic (ih) cccDNA, ih total hepatitis B virus (HBV) DNA, serum HBV DNA and to a lesser extent HBV surface antigen (HBsAg). In situations where serum HBV DNA levels become undetectable or HBsAg loss is achieved, HBcrAg can still be detectable. This marker is helpful in differentiation of HBeAg-negative chronic hepatitis from HBeAg-negative chronic infection, predicting spontaneous or treatment-induced HBeAg seroconversion, sustained response to nucleos(t)ide analogue (NA), risk of HBV reactivation in occult HBV infection under immunosuppressive therapies, and risk of hepatocellular carcinoma (HCC) development as well as post-operative HCC recurrence.

CONCLUSIONS

HBcrAg is a potential surrogate marker of cccDNA. It may soon become a useful marker for disease monitoring, predicting treatment response and disease outcome of chronic hepatitis B.

Inverse relationship between hepatic steatosis and hepatitis B viremia: Results of a large case-control study

The potential interaction between chronic hepatitis B (CHB) and nonalcoholic fatty liver disease (NAFLD), two of the most prevalent liver diseases worldwide, has not been well defined. We performed liver stiffness (LS) and controlled attenuation parameter (CAP) measurements using transient elastography in 1202 CHB patients. Of these, 601 steatotic patients were matched with nonsteatotic controls in a 1:1 ratio by age, gender, nucleoside analogue treatment status, and treatment duration. Severe fibrosis was defined according to EASL-ALEH criteria, and steatosis was defined as CAP ≥222 dB m^-1 . Anthropometric measurements and metabolic-related parameters were recorded. The mean age of the 1202 patients (51.4% male) was 51.8 years. 696 patients (57.9%) were on nucleoside analogues for a median duration of 76.2 months. Among treatment-naïve patients, median serum HBV DNA was lower in steatotic individuals than in controls (3.0 vs 3.4 log IU mL^-1 , P < .05), with this inverse relationship remaining significant in multivariate analysis (odds ratio 0.859, 95% CI 0.743-0.994, P < .05). With increased steatosis severity, there was a stepwise decrease in median HBV DNA levels (3.1 and 2.6 log IU mL^-1 in no steatosis and severe steatosis, respectively, P = .032). Steatosis was associated with a higher median LS (5.4 kPa vs 5.0 kPa, P < .001). Severe steatosis, when compared to mild/moderate steatosis, was associated with an increased percentage of severe fibrosis (23.2% and 12.6%, respectively, P = .005). We conclude that severe steatosis was associated with increased fibrosis in CHB patients. Increasing steatosis was independently associated with lower serum HBV DNA levels, suggesting its potential negative effects on viral replication.

Relationship between HBsAg, HBcrAg and hepatocellular carcinoma in patients with undetectable HBV DNA under nucleos(t)ide therapy

We examined the relationship between hepatitis B surface and core-related antigens (HBsAg, HBcrAg) and hepatocellular carcinoma (HCC) development in patients with undetectable serum HBV DNA receiving nucleos(t)ide analogue (NA). Seventy-six HBV carriers with undetectable HBV DNA (<20 IU/mL) who subsequently developed HCC were compared with 152 matched controls. Clinical and laboratory parameters (including novel assays to measure linearized HBsAg [HQ-HBsAg] and HBcrAg) were analysed. There were no significant differences in HBsAg/HQ-HBsAg levels between the two groups. There was a significant difference in the median values of both pre- and post-NA HBcrAg levels between the HCC and control groups (pre-treatment: 279.0 vs 35.4 kU/mL, P=.005; post-treatment: 10.2 vs 1.7 kU/mL, P=.005, respectively). For the whole HCC group, a cut-off value of post-treatment HBcrAg level ≥7.8 kU/mL yielded an area under receiver operating curve (AUROC) of 0.61 with a negative predictive value (NPV) of 77.0%. The OR of HCC development was 3.27. For noncirrhotic patients, the median values of post-treatment HBcrAg level of HCC group and controls were 10.2 and 1.0 kU/mL, respectively (P=.001). A cut-off value of HBcrAg level ≥7.9 kU/mL yielded an AUROC of 0.70 with a NPV of 80.6%. The OR of HCC development was 5.95. A higher pre- and post-NA treatment HBcrAg level (but not HBsAg) was associated with an increased risk of HCC development in patients achieving undetectable serum HBV DNA while on NA therapy. HBcrAg may serve as a novel risk marker for HCC in this group of patients.

Effects of nucleoside analogue prescription for hepatitis B on the incidence of liver cancer in Hong Kong: a territory-wide ecological study

BACKGROUND

The temporal relationship between nucleoside analogue therapy for chronic hepatitis B (CHB) and liver cancer development has not been evaluated at a population level.

AIM

To investigate the impact of nucleoside analogue prescription on liver cancer incidence in a CHB-prevalent region.

METHODS

We obtained territory-wide nucleoside analogue prescription data from 1999, when nucleoside analogue was first available in Hong Kong, to 2012 and the population-based liver cancer incidence data from 1990 to 2012. We compared the liver cancer incidences from 1990 to 1998 and 1999 to 2012 with adjustment for local hepatitis B surface antigen seroprevalence.

RESULTS

Nucleoside analogue prescription patient headcount increased from 2006 per year in 1999 to 26 411 in 2012. Prescription volume in 2012 was highest among 55-64 years (30.3%), higher than 65-74 years (13.0%) and ≥75 years (5.8%). Age-standardised liver cancer incidence 1999-2012 decreased by 1.88%/year (95% CI 3.34% to 0.42%/year). NA therapy was associated with decline in age-adjusted liver cancer incidence (2.7 per 100 000 persons, P < 0.001, 95% CI 1.4-4.0 per 100 000 persons). Fifty-five to sixty-four years age group had the most significant decline (men: 24.0 per 100 000 persons, P = 0.001, 95% CI 11.4-36.6 per 100 000 persons; women: 8.5 per 100 000 persons, P = 0.009, 95% CI 2.3-14.6 per 100 000 persons). No significant association was noted in age groups 65-74 years and ≥75 years (both P > 0.05).

CONCLUSIONS

Nucleoside analogue prescription was associated with a reduction of overall liver cancer incidence in a CHB-prevalent region. The lack of association among individuals of ≥65 years was consistent with the low nucleoside analogue prescription volume in elderly patients, mitigating the impact of CHB treatment on liver cancer.

Body-mass index is associated with fibrosis regression during long-term nucleoside analogue therapy in chronic hepatitis B

BACKGROUND

Factors influencing changes in liver stiffness measurements during long-term nucleoside analogue therapy for chronic hepatitis B (CHB) have not been thoroughly investigated.

AIM

To identify determinants of on-treatment fibrosis regression in CHB.

METHODS

We performed follow-up liver stiffness and controlled attenuation parameter measurements on nucleoside analogue-treated CHB patients with severe liver fibrosis, according to EASL-ALEH criteria, diagnosed by transient elastography in 2006-2008. Anthropometric measurements and different metabolic parameters were recorded.

RESULTS

Among 257 patients with severe liver fibrosis by initial transient elastography, 123 (47.9%) were recruited for reassessment. Median treatment duration was 87.5 (interquartile range 75.3-102.2) months; 97.5% had undetectable HBV DNA. There was a significant reduction in median liver stiffness from 14.6 to 8.3 kPa (P < 0.001). A total of 29.3% had fibrosis regression, with lower rates of 17.9%, 14.9% and 11.5% noted in patients with body-mass index (BMI) ≥25 kg/m² , metabolic syndrome and diabetes, respectively. Absence of BMI ≥25 kg/m² , diabetes and metabolic syndrome, when compared with presence of any one of these three factors, was associated with increased fibrosis regression (43.1% vs. 16.9%, P = 0.001). Multivariate analysis found a lower BMI to be the only factor independently associated with fibrosis regression (P = 0.034, odds ratio 0.68, 95% CI 0.48-0.97). No association was noted between controlled attenuation parameter measurements and fibrosis regression (P > 0.05).

CONCLUSION

An increased BMI hindered fibrosis regression in patients with chronic hepatitis B during nucleoside analogue treatment, suggesting that control of metabolic risk factors, in addition to virologic suppression via antiviral therapy, might be needed to halt the fibrogenic process in chronic hepatitis B.

Intrahepatic hepatitis B virus replication and liver histology in subjects with occult hepatitis B infection

We studied the intrahepatic hepatitis B virus (HBV) replicative status in 40 people with occult hepatitis B infection (OBI) and 40 patients with chronic hepatitis B (CHB). Intrahepatic HBV DNA, covalently closed circular DNA (cccDNA), and pre-genomic RNA (pgRNA) were quantified. Patients with OBI had median necroinflammation and fibrosis scores of 1 and 0, respectively. Intrahepatic total HBV DNA, cccDNA and pgRNA were detectable in 30 (77%), one (3%) and five (13%) of the participants with OBI, respectively. People with OBI had lower median intrahepatic total HBV DNA than the patients with CHB (p < 0.0001). They had nearly normal liver histology and low intrahepatic HBV replication.

Linearized hepatitis B surface antigen and hepatitis B core-related antigen in the natural history of chronic hepatitis B

Changes in two novel HBV serological markers, linearized hepatitis B surface antigen (HQ-HBsAg) and hepatitis B core-related antigen (HBcrAg), in the natural history of chronic hepatitis B (CHB) have not been well characterized. Serum HQ-HBsAg and HBcrAg levels of 404 Asian treatment-naïve CHB patients were analysed in a cross-sectional manner. Patients were categorized into five groups: immune tolerant (IT group, n=52), immune clearance (IC group, n=105), hepatitis B e antigen (HBeAg)-negative hepatitis (ENH group, n=97), HBeAg-negative quiescent group (ENQ group, n=95) and CHB with hepatitis B surface antigen (HBsAg) seroclearance (SC group, n=55). HQ-HBsAg and HBcrAg were measured and correlated with HBV DNA, HBsAg, HBV genotype and clinical parameters. HQ-HBsAg showed good correlation with HBsAg, especially in the ENQ group (r=0.874, p<0.001). Correlation of HQ-HBsAg with HBV DNA was less prominent and weakest in the ENH group (r=0.268, p 0.008). HBcrAg correlated best with HBV DNA in the ENQ group (r=0.537, p<0.001). In the ENQ group, 42.1% of patients had undetectable HBcrAg; this subgroup of patients, when compared with those with detectable HBcrAg, had significantly lower median HBV DNA (3.17/4.48 log IU/mL, p<0.001) and HBsAg (5.05/5.96 log mIU/mL, p<0.001) levels. Forty per cent of the SC group patients had detectable HQ-HBsAg and/or HBcrAg up to 42 months after HBsAg seroclearance. When comparing anti-HBs positivity and median time after HBsAg seroclearance in the SC group with and without detectable HQ-HBsAg/HBcrAg, there was no significant difference (22.7% and 36.4%, respectively, p 0.284, and 76.5 and 93.2 months, respectively, p 0.245). HQ-HBsAg and HBcrAg showed unique patterns of distribution throughout the five disease phases of CHB, including high detectability rates after HBsAg seroclearance, opening up different possibilities for their applicability.

Role of IL28B and inosine triphosphatase polymorphisms in the treatment of chronic hepatitis C virus genotype 6 infection

IL28B and inosine triphosphatase (ITPA) polymorphisms are able to predict treatment response and degree of ribavirin-related anaemia, respectively, in the treatment of chronic hepatitis C virus (HCV) infection. However, their roles in the treatment of chronic HCV genotype 6 remain undetermined. Sixty patients who were infected with HCV genotype 6 were commenced on 48 weeks of combination pegylated interferon and ribavirin therapy. Response to therapy, profiles of haemoglobin changes and platelet counts during therapy and their associations with IL28B rs8099917 and ITPA rs1127354 polymorphisms were analysed. The overall sustained virologic response (SVR) rate was 91.7%. 18 patients (30.0%) required a reduction in ribavirin dosage. The distribution of IL28B rs8099917 TT/TG genotypes and ITPA rs1127354 CC/CA genotypes were in Hardy-Weinberg equilibrium. IL28B rs8099917 TT genotype, when compared to TG genotype, was significantly associated with an increased SVR rate (96.2% and 62.5%, respectively) and was the only clinical parameter that predicted SVR (P = 0.014). The same significant association was observed when analysing allelic frequencies (T vs G, P = 0.001). ITPA rs1127354 CA genotype, when compared to CC genotype, was associated with lesser degree of anaemia throughout therapy (P < 0.05 for all time points). ITPA polymorphisms showed no association with changes in platelet count throughout therapy (P > 0.05 for all time points) and was not associated with SVR (P = 0.640). In chronic HCV genotype 6 infection, IL28B polymorphisms were associated with response to therapy. ITPA polymorphisms influenced the degree of anaemia but not thrombocytopenia during therapy.

Prognostic significance of liver stiffness for hepatocellular carcinoma and mortality in HBeAg-negative chronic hepatitis B

The prognostic value of liver stiffness measurements for chronic hepatitis B (CHB) is not known. The present study aimed to investigate the use of transient elastography in predicting hepatocellular carcinoma (HCC) development and mortality in patients with CHB. Five hundred and twenty-eight patients with HBeAg-negative CHB underwent liver stiffness measurements and were prospectively followed up every 3-6 months for a median length of 35 months. The patients were divided into those with liver stiffness < 10 kPa (group 1) and ≥ 10 kPa (group 2). Of the 528 patients, 324 (61%) were men. The median age was 42 years. Compared with group 1, group 2 had a higher percentage of men, with higher median levels of age, liver biochemistry, and viral load. At the third year of follow-up, the cumulative incidence of HCC was higher in group 2 compared with group 1 (9%vs 0%, respectively, P < 0.001). The cumulative liver-related mortality was also higher in group 2 compared to group 1 (4%vs 0%, respectively, P < 0.001). After multivariate analysis, only liver stiffness measurement (LSM) was significantly associated with HCC development and mortality. There was also a higher cumulative incidence of hepatitis flares in group 2 compared to group 1 (46%vs 14%, respectively, P = 0.001) in patients with normal ALT, with higher LSM and AST being significantly associated with subsequent flares. In HBeAg-negative CHB patients, a liver stiffness measurement of ≥ 10 kPa was associated with a significantly increased risk of subsequent HCC development and mortality.

Significant changes in liver stiffness measurements in patients with chronic hepatitis B: 3-year follow-up study

For patients with chronic hepatitis B (CHB) infection, changes in liver stiffness measurement (LSM) over time are not known. We examined changes longitudinally in a cohort of patients. Four hundred and twenty-six patients with CHB underwent transient elastography. Patients were followed regularly, and repeat elastography was performed at 3 years. Hepatitis serology, viral load and routine liver biochemistry were monitored. Of the 426 patients, 38 (9%) were hepatitis B e-antigen (HBeAg)-positive, 293 (69%) were HBeAg-negative and 95 (22%) were patients with prior hepatitis B surface antigen (HBsAg) seroclearance. A total of 110 patients received oral antiviral therapy. There was a significant decline of LSMs at the follow-up measurement compared to baseline (6.1 vs 7.8 kPa respectively, P = 0.002) in treated patients who had elevated alanine aminotransferase (ALT) at baseline and subsequent normalization after 3 years (normal ALT limit being 30 U/L for males and 19 U/L for females). In nontreated patients, only the patients with persistently normal ALT at both time points had significantly lower LSMs at the follow-up measurement compared to baseline: 4.9 vs 5.3 kPa, respectively, in patients who remained positive for HBsAg (P = 0.005) and 5.1 vs. 5.4 kPa, respectively, in patients who had HBsAg seroclearance (P = 0.026). In patients who remained positive for HBsAg, independent factors associated with a significant decline in LSM of ≥1 kPa included antiviral therapy (P = 0.011) and the ALT levels at the follow-up time point (P = 0.024). Thus, in patients with CHB, a significant decline in LSM after 3 years was observed in treated patients with ALT normalization and in untreated patients who had persistently normal ALT. Antiviral therapy and follow-up ALT levels were independent significant factors associated with a decline in LSM.