Serum hepatitis B surface antigen levels and their utility as a predictor of sustained virological response after antiviral treatment

Hepatitis B Surface Antigen Levels Are Related to Spontaneous Hepatitis B Surface Antigen Seroconversion in Inactive Hepatitis B Carriers

BACKGROUND

The cure for hepatitis B is defined as the hepatitis B surface antigen (HBsAg) seroclearance and/or seroconversion. Predictors of spontaneous seroconversion are not well described. The objective of this study is to identify predictors of spontaneous HBsAg seroconversion from community practice.

METHODS

We performed a matched analysis of patients who HBsAg seroconverted (cases) and patients who did not HBsAg seroconvert (control) in a 1:5 ratio according to date of clinic visit between 2014 and 2019 in a large community practice situated in Los Angeles area. Baseline laboratory and clinical data were collected. Univariate analysis and 2-sided t tests were performed, χ test for proportions, and logistic regression.

RESULTS

We identified 14 cases and 70 controls. The mean (±SD) ages of the cases and controls were 53.6 (±12.2) and 49.5 (±13.1), respectively (P=0.45). Most patients were women, and all patients were of Asian descent. There were statistically significant mean (±SD) baseline differences between cases and controls in HBsAg titers (459.8±311.0 and 782.0±393.3 IU/mL, P=0.01) and alanine aminotransferase (ALT) values (17.6±4.4 and 25.1±16.7 IU/mL, P<0.01), respectively. Baseline hepatitis B virus DNA and other pertinent laboratory values did not differ between cases and controls. Eleven of 14 cases (79%) and 11 of 70 controls (16%) baseline HBsAg titers were <1000 IU/mL (P<0.01). The results of a logistic regression demonstrated that HBsAg titers and ALT values were predictor variables for HBsAg seroconversion (P=0.01 and <0.01, respectively).

CONCLUSIONS

Spontaneous HBsAg seroclearance and seroconversion is an uncommon event in patients with chronic hepatitis B. The most important predictors of seroconversion are HBsAg titers<1000 IU/mL and low baseline ALT values.

Treatment options beyond IFNα and NUCs for chronic HBV infection: expectations for tomorrow

Chronic hepatitis B virus (HBV) infection may progress to cirrhosis, hepatocellular carcinoma (HCC) and end-stage liver failure with time. Interruption of this process can only be achieved through effective antiviral treatment. This approach has so far involved the use of immunomodulators such as pegylated interferon alpha (Peg-IFNα) for a finite period of up to a year and nucleos-(t)ide analogues (NUCs) for treatment over much longer periods of time. The latter act by suppressing HBV replication at the level of DNA synthesis by inhibiting the viral reverse transcriptase/DNA polymerase and causing premature termination of DNA synthesis. The ideal treatment end point is loss of HBsAg in both HBeAg+ve and HBeAg-ve patients following monotherapy. This, however, is only achievable in a minority of patients. Secondary outcomes are durable HBeAg loss and seroconversion to anti-HBe, which occur in about 18-30% of HBeAg+ve patients depending on the antiviral used, and sustained suppression of HBV-DNA accompanied by biochemical normalization and histological improvement in non-HBeAg+ve seroconverting and HBeAg-ve patients. There is therefore a need for additional direct-acting antivirals (DAAs) targeting different stages of the life cycle of the virus, as well as immunotherapeutic approaches. Such developments may pave the way for their use either alone or more likely in combination in the fight against chronic HBV infection. Such drugs or approaches, which are currently undergoing preclinical or clinical testing, are the subject of this review.

HBeAg negative variants and their role in the natural history of chronic hepatitis B virus infection

Molecular virology methods including polymerase chain reaction, cloning and sequencing have revolutionised our understanding of viral genome variation. In the case of hepatitis B virus (HBV), sequencing studies have identified a number of virus variants normally found during the natural course of chronic infection. The appearance of the precore stop codon (with G-for-A substitution at position 1896) and basal core promoter (BCP) (with A-for-T and G-for-A, at positions 1762 and 1764, respectively) variants which reduce or abrogate hepatitis B e antigen (HBeAg) production, heralds the initiation of the seroconversion phase from HBeAg to anti-HBe positivity. The gradual removal of the tolerogenic effect of HBeAg leads to the awakening of the immune response (immune clearance phase). Most patients after HBeAg seroconversion become “inactive HBsAg carriers”. However during the course of infection precore and/or BCP variants may emerge and be selected leading to HBeAg negative chronic hepatitis B (CHB) with high viremia levels (reactivation phase). The prevalence of HBeAg negative CHB has been increasing over the last few decades and has become the commonest type of HBV infection in many countries of the world. This probably reflects the aging of existing HBV carriers and the effective prevention measures restricting new HBV infections. Frequent acute exacerbations accompanied by high viral replication, elevated alanine aminotransferase levels and histological activity are a common feature of HBeAg negative CHB leading to cirrhosis much faster than in HBeAg positive CHB patients.

Changes of HBsAg and interferon-inducible protein 10 serum levels in naive HBeAg-negative chronic hepatitis B patients under 4-year entecavir therapy

BACKGROUND & AIMS

Serum HBsAg levels might represent an important predictor of sustained off-treatment response in HBeAg-negative chronic hepatitis B (CHB). We evaluated the changes of HBsAg and interferon-inducible protein 10 (IP10) serum levels in HBeAg-negative CHB patients treated with entecavir.

METHODS

114 patients received entecavir for a median of 4.3 years. HBsAg levels were determined at baseline, 6 and 12 months and every year thereafter until year-4. IP10 levels were measured at baseline and annually until year-4 in 76 patients.

RESULTS

Virological remission rates were high (year-1: 94%, after year-2: 97-98%). Compared to baseline, HBsAg levels decreased by a median of 0.03, 0.13, 0.17, 0.22, and 0.32 log₁₀ IU/ml at 6 months and 1, 2, 3, and 4 years, respectively (p≤0.001 for all comparisons). The proportions of patients with HBsAg decline of ≥0.5 or ≥1 log₁₀ IU/ml were 9% or 6% at year-1 and 21% or 10% at the last visit. Median IP10 levels (pg/ml) did not change from baseline to year-1 or -2 (245 vs. 229 or 251), but increased at year-3 and -4 (275 and 323, p<0.030). HBsAg drop ≥0.5 log₁₀ was associated with baseline IP10 or IP10 >350 pg/ml (p≤0.002). HBsAg loss occurred in 4/114 (3.5%) patients or in 1/2, 3/21, and 0/91 patients with baseline HBsAg <100, 100-1000 and >1000 IU/ml, respectively (p<0.001).

CONCLUSIONS

In HBeAg-negative CHB patients, 4-year entecavir therapy decreases serum HBsAg levels, but the rate of decline is rather slow. Serum IP10 levels represent a promising predictor of HBsAg decline in this setting.

Direct acting antivirals for the treatment of chronic viral hepatitis

The development and evaluation of antiviral agents through carefully designed clinical trials over the last 25 years have heralded a new dawn in the treatment of patients chronically infected with the hepatitis B and C viruses, but not so for the D virus (HBV, HCV, and HDV). The introduction of direct acting antivirals (DDAs) for the treatment of HBV carriers has permitted the long-term use of these compounds for the continuous suppression of viral replication, whilst in the case of HCV in combination with the standard of care [SOC, pegylated interferon (PegIFN), and ribavirin] sustained virological responses (SVRs) have been achieved with increasing frequency. Progress in the case of HDV has been slow and lacking in significant breakthroughs.This paper aims to summarise the current state of play in treatment approaches for chonic viral hepatitis patients and future perspectives.