Factors associated with the decrease in hepatitis B surface antigen titers following interferon therapy in patients with chronic hepatitis B: Is interferon and adefovir combination therapy effective?

HBsAg, Subviral Particles, and Their Clearance in Establishing a Functional Cure of Chronic Hepatitis B Virus Infection

In diverse viral infections, the production of excess viral particles containing only viral glycoproteins (subviral particles or SVP) is commonly observed and is a commonly evolved mechanism for immune evasion. In hepatitis B virus (HBV) infection, spherical particles contain the hepatitis B surface antigen, outnumber infectious virus 10 000-100 000 to 1, and have diverse inhibitory effects on the innate and adaptive immune response, playing a major role in the chronic nature of HBV infection. The current goal of therapies in development for HBV infection is a clinical outcome called functional cure, which signals a persistent and effective immune control of the infection. Although removal of spherical SVP (and the HBsAg they carry) is an important milestone in achieving functional cure, this outcome is rarely achieved with current therapies due to distinct mechanisms for assembly, secretion, and persistence of SVP, which are poorly targeted by direct acting antivirals or immunotherapies. In this Review, the current understanding of the distinct mechanisms involved in the production and persistence of spherical SVP in chronic HBV infection and their immunoinhibitory activity will be reviewed as well as current therapies in development with the goal of clearing spherical SVP and achieving functional cure.

Benefit of transaminase elevations in establishing functional cure of HBV infection during nap-based combination therapy

Treatment of HBV infection with nucleic acid polymers and pegIFN is accompanied by transaminase elevations in 95% of participants. HBV viral rebound, partial cure (HBV DNA < 2000 IU/mL, normal ALT) or functional cure (HBV DNA target not detected, HBsAg <LLOQ, normal ALT) occurred in 27%, 38% and 35% of participants. Correlations between ALT, AST and GGT elevations, virologic baseline, response during therapy and HBV therapeutic outcome were investigated. A retrospective analysis of all 40 participants in the REP 401 study (NCT02565719) included maxima and area under the curve for ALT, AST and GGT, baseline virology, HBsAg and anti-HBs response and HBV therapeutic outcomes. ALT, AST and GGT elevations were asymptomatic, independent of baseline virologic status and anti-HBs response but correlated with HBsAg reduction ≥3 log₁₀ from baseline. Functional cure was associated with significantly lower HBsAg during the nadir of ALT flares versus viral rebound or partial cure. ALT elevations >3X ULN while HBsAg was <1 IU/mL occurred in 3/11 (27%), 11/15 (74%) and 14/14 (100%) of participants experiencing viral rebound, partial or functional cure. ALT elevation >3X ULN during HBsAg <1 IU/mL and <10 IU/mL were the best predictors of partial and functional cure. In conclusion, elevations in ALT, AST or GGT while HBsAg <10 IU/ml during therapy with REP 2139 + pegIFN are associated with partial and functional cure. More potent HBsAg reduction during flare nadir is associated with the establishment of functional cure, suggesting a critical role for HBsAg-specific immunity to achieve this outcome. These on-therapy milestones may have similar positive prognostic value with other combination therapies.

Transaminase Elevations during Treatment of Chronic Hepatitis B Infection: Safety Considerations and Role in Achieving Functional Cure

While current therapies for chronic HBV infection work well to control viremia and stop the progression of liver disease, the preferred outcome of therapy is the restoration of immune control of HBV infection, allowing therapy to be removed while maintaining effective suppression of infection and reversal of liver damage. This “functional cure” of chronic HBV infection is characterized by the absence of detectable viremia (HBV DNA) and antigenemia (HBsAg) and normal liver function and is the goal of new therapies in development. Functional cure requires removal of the ability of infected cells in the liver to produce the hepatitis B surface antigen. The increased observation of transaminase elevations with new therapies makes understanding the safety and therapeutic impact of these flares an increasingly important issue. This review examines the factors driving the appearance of transaminase elevations during therapy of chronic HBV infection and the interplay of these factors in assessing the safety and beneficial nature of these flares.

The impact of IFNL3 genotype on interferon treatment outcome in patients chronically infected with hepatitis B virus: A meta-analysis

BACKGROUND

Polymorphisms near the interferon lambda 3 (IFNL3, also known as IL28B) have been proposed to be associated with interferon (IFN)-induced hepatitis C virus (HCV) clearance, but the impact of IFNL3 variations on the result of IFN-based therapy in chronic hepatitis B (CHB) infection is still poor understood.

METHODS

The purpose of this study was to evaluate the relationship between the IFNL3 polymorphisms and the effectiveness of IFN therapy in patients infected with CHB by means of meta-analysis. PubMed and Embase were utilized to identify relevant studies. Odds ratio (OR) and 95% confidence interval (CI) were analysed together to assess the strength of the association. Subgroup analysis was mainly performed according to HBeAg.

RESULTS

Twelve studies of 1645 CHB patients met the inclusion criteria and were selected in our meta-analysis. One polymorphism, rs12979860, near to the IFNL3 gene had significant association with the response of CHB patients to IFN-based therapy (OR = 2.35, 95% CI: 1.61-3.42 in allelic model). Another polymorphism, rs8099917, had a similar result (OR = 1.57, 95% CI: 1.03-2.40 in dominant model; and OR = 1.88, 95% CI: 1.21-2.90 in allelic model). When stratified by HBeAg, the antiviral outcome was markedly influenced by both two SNPs in HBeAg positive group (for rs12979860, OR = 1.90, 95% CI: 1.31-2.76 and OR = 2.07, 95% CI: 1.26-3.41 in dominant and allelic models respectively; for rs8099917, OR = 1.67, 95% CI: 1.04-2.67 in dominant model and OR = 1.77, 95% CI: 1.10-2.85 in allelic model).

CONCLUSION

We concluded that two polymorphisms (rs12979860 and rs8099917) of IFNL3 may play a crucial role in the IFN-based treatment of CHB, especially in HBeAg positive group.