Moving toward hepatitis B virus functional cure - the impact of on-treatment kinetics of serum viral markers

Risk of Hepatocellular Carcinoma Decreases After Antiviral Therapy-Induced HBsAg Seroclearance

BACKGROUND

Antiviral therapy (AVT) reduces the risk of hepatitis B virus-related hepatocellular carcinoma (HCC).

AIMS

The difference in risk of HCC after hepatitis B surface antigen (HBsAg) seroclearance to the AVT status was explored.

METHODS

Patients with chronic hepatitis B who achieved HBsAg seroclearance were retrospectively evaluated. The primary outcome was the development of HCC after HBsAg seroclearance.

RESULTS

Of the study population, 1280 (84.2%) and 241 (15.8%) patients achieved HBsAg seroclearance without (spontaneous clearance group) and with AVT (AVT-induced clearance group), respectively. HCC cumulative incidence was comparable between the two groups (hazard ratio [HR] = 0.461; log-rank test, p = 0.197), whereas it was significantly lower in the AVT-induced HBsAg clearance group than in the spontaneous HBsAg clearance group in inverse probability of treatment weighting analysis (HR = 0.442; log-rank test, p = 0.004). In multivariate analysis, spontaneous HBsAg clearance, albumin-bilirubin (ALBI) grade ≥ 2, cirrhosis, and platelet count < 50 × 109/L were independently associated with the increased risk of HCC. The newly established antiviral therapy, cirrhosis, ALBI, and platelet count (ACAP) scores had a C-index of 0.765, and the time-dependent areas under the curve of HCC prediction at 5 and 8 years were 0774 and 0.823, respectively.

CONCLUSION

The risk of HCC differed according to the AVT status after HBsAg seroclearance.

Rapid monophasic HBsAg decline during nucleic-acid polymer-based therapy predicts functional cure

BACKGROUND AND AIMS

Analyzing the interplay among serum HBV DNA, HBsAg, anti-HBs, and alanine aminotransferase (ALT) during nucleic-acid polymer (NAP)-based therapy for chronic hepatitis B provides a unique opportunity to identify kinetic patterns associated with functional cure.

METHODS

All participants with HBeAg-negative chronic HBV infection in the REP 401 study (NCT02565719) first received 24 weeks of tenofovir-disoproxil-fumarate (TDF) monotherapy. The early triple therapy group (n = 20) next received 48 weeks of TDF+pegylated interferon-α2a (pegIFN)+NAPs. In contrast, the delayed triple therapy group (n = 20) next received 24 weeks of TDF+pegIFN before 48 weeks of triple therapy. Three participants discontinued treatment and were excluded. Functional cure (HBsAg and HBV DNA not detectable with normal ALT) was assessed at 48 weeks post-treatment. Different kinetic phases were defined by at least a 2-fold change in slope. A single-phase decline was categorized as monophasic, and 2-phase declines were categorized as biphasic.

RESULTS

Fourteen (35%) participants achieved a functional cure. HBV DNA remained below or near undetectable for all participants by the end of TDF monotherapy and during subsequent combination therapies. Three HBsAg kinetic patterns were found in both the early and delayed groups, nonresponders (n = 4 and n = 4), monophasic (n = 11 and n = 11), and biphasic (n = 4 and n = 3), respectively. All participants who achieved a functional cure had a monophasic HBsAg kinetic pattern during triple therapy. Among participants with a monophasic HBsAg decline, those who had a functional cure had a shorter median time to HBsAg loss of 21 (interquartile range=11) weeks compared with those who did not achieve functional cure [median: 27 (7) weeks] (p = 0.012).

CONCLUSIONS

Functional cure was associated with a rapid monophasic HBsAg decline during NAP-based therapy. A nonmonophasic HBsAg kinetic pattern had a 100% negative predictive value (NPV) for a functional cure.

Hepatitis B and Hepatitis D Viruses: A Comprehensive Update with an Immunological Focus

Hepatitis B virus (HBV) and hepatitis delta virus (HDV) are highly prevalent viruses estimated to infect approximately 300 million people and 12-72 million people worldwide, respectively. HDV requires the HBV envelope to establish a successful infection. Concurrent infection with HBV and HDV can result in more severe disease outcomes than infection with HBV alone. These viruses can cause significant hepatic disease, including cirrhosis, fulminant hepatitis, and hepatocellular carcinoma, and represent a significant cause of global mortality. Therefore, a thorough understanding of these viruses and the immune response they generate is essential to enhance disease management. This review includes an overview of the HBV and HDV viruses, including life cycle, structure, natural course of infection, and histopathology. A discussion of the interplay between HDV RNA and HBV DNA during chronic infection is also included. It then discusses characteristics of the immune response with a focus on reactions to the antigenic hepatitis B surface antigen, including small, middle, and large surface antigens. This paper also reviews characteristics of the immune response to the hepatitis D antigen (including small and large antigens), the only protein expressed by hepatitis D. Lastly, we conclude with a discussion of recent therapeutic advances pertaining to these viruses.