Ideal Cure for Hepatitis B Infection: The Target is in Sight

Safety, antiviral activity and pharmacokinetics of JNJ-64530440, a novel capsid assembly modulator, as 4 week monotherapy in treatment-naive patients with chronic hepatitis B virus infection

OBJECTIVES

We investigated JNJ-64530440 (a hepatitis B virus capsid assembly modulator) safety, antiviral activity and pharmacokinetics in patients with chronic hepatitis B (CHB) (Phase 1b, NCT03439488).

METHODS

Twenty treatment-naive, HBeAg-positive or -negative CHB patients were randomized 4‍:‍1 to JNJ-64530440 750 mg once or twice daily, or placebo for 28 days.

RESULTS

All patients (mean age 43.8 years; 85% male; 70% White; 20% HBeAg positive) completed dosing/28 day follow-up. Mild-to-moderate treatment-emergent adverse events occurred in 3/4 (placebo), 6/8 (once-daily) and 4/8 (twice-daily) patients; mostly fatigue, increased alanine aminotransferase, decreased neutrophil count, and headache. Hepatitis B virus (HBV) DNA was substantially reduced; mean (range) changes from baseline at day 29 were: -3.2 (-2.4 to -3.9) (once-daily) and -3.3 (-2.6 to -4.1) (twice-daily) log10 IU/mL; placebo 0.1 (0.7 to -0.6) log10 IU/mL. HBV DNA levels were below the lower limit of quantification (LLOQ) in 5/8 (once-daily) and 3/8 (twice-daily) patients. For patients with detectable baseline HBV RNA, mean (SE) changes versus baseline in HBV RNA at day 29 were: -2.65 (0.81) (once-daily) and -2.94 (0.33) (twice-daily) log10 copies/mL. HBV RNA levels were 'target not detected' in 4/6 (once-daily) and 3/7 (twice-daily) patients. JNJ-64530440 pharmacokinetics in CHB patients were comparable with those in healthy volunteers.

CONCLUSIONS

JNJ-64530440 750 mg once-daily or twice-daily for 28 days was well tolerated and achieved potent antiviral activity in CHB patients.

Immunological Analysis of the Hepatitis B Virus "a" Determinant Displayed on Chimeric Virus-Like Particles of Macrobrachium rosenbergii Nodavirus Capsid Protein Produced in Sf9 Cells

Chimeric virus-like particles (VLPs) have been widely exploited for various purposes including their use as vaccine candidates, particularly due to their ability to induce stronger immune responses than VLPs consisting of single viral proteins. In the present study, VLPs of the Macrobrachium rosenbergii nodavirus (MrNV) capsid protein (Nc) displaying the hepatitis B virus “a” determinant (aD) were produced in Spodoptera frugiperda (Sf9) insect cells. BALB/c mice immunised with the purified chimeric Nc-aD VLPs elicited a sustained titre of anti-aD antibody, which was significantly higher than that elicited by a commercially available hepatitis B vaccine and Escherichia coli-produced Nc-aD VLPs. Immunophenotyping showed that the Sf9-produced Nc-aD VLPs induced proliferation of cytotoxic T-lymphocytes and NK1.1 natural killer cells. Furthermore, enzyme-linked immunospot (ELISPOT)analysis showed the presence of antibody-secreting memory B cells in the mice splenocytes stimulated with the synthetic aD peptide. The significant humoral, natural killer cell and memory B cell immune responses induced by the Sf9-produced Nc-aD VLPs suggest that they present good prospects for use as a hepatitis B vaccine candidate.

Mapping the Interactions of HBV cccDNA with Host Factors

Hepatitis B virus (HBV) infection is a major health problem affecting about 300 million people globally. Although successful administration of a prophylactic vaccine has reduced new infections, a cure for chronic hepatitis B (CHB) is still unavailable. Current anti-HBV therapies slow down disease progression but are not curative as they cannot eliminate or permanently silence HBV covalently closed circular DNA (cccDNA). The cccDNA minichromosome persists in the nuclei of infected hepatocytes where it forms the template for all viral transcription. Interactions between host factors and cccDNA are crucial for its formation, stability, and transcriptional activity. Here, we summarize the reported interactions between HBV cccDNA and various host factors and their implications on HBV replication. While the virus hijacks certain cellular processes to complete its life cycle, there are also host factors that restrict HBV infection. Therefore, we review both positive and negative regulation of HBV cccDNA by host factors and the use of small molecule drugs or sequence-specific nucleases to target these interactions or cccDNA directly. We also discuss several reporter-based surrogate systems that mimic cccDNA biology which can be used for drug library screening of cccDNA-targeting compounds as well as identification of cccDNA-related targets.