Editor’s Note:

Currently, some patients with chronic hepatitis B (CHB) can achieve clinical cure through interferon-based antiviral treatment. To pursue clinical cure for a larger population, there is a flurry of activity in the development of new drugs. Six studies on new therapies for hepatitis B were selected for presentation at the 2023 American Association for the Study of Liver Diseases (AASLD) Annual Meeting, to be discussed in the “Hepatitis B: New Therapies for HBV and HDV” session. Hepatology Digest has compiled this information for interested readers, and the session is scheduled for online access on November 12th at 8:30 AM local time.

01 Preliminary Treatment Response of Vebicorvir, Nucleos(t)ide Reverse Transcriptase Inhibitors, and AB-729 Combination Therapy in Viral Suppressed HBeAg-Negative CHB Patients: Analysis from an Open-Label Phase 2 Study

At this year’s AASLD Annual Meeting, Gerry MacQuillan and colleagues from Australia reported the analysis results of HBeAg-negative chronic hepatitis B (CHB) patients under viral suppression, treated with vebicorvir, nucleos(t)ide reverse transcriptase inhibitors (NrtI), and AB-729 for 48 weeks [1].

This open-label study evaluated the safety and efficacy of vebicorvir (VBR) + AB-729 + NrtI treatment in viral suppressed HBeAg-negative CHB patients (NCT04820686). VBR is a first-generation core inhibitor, and AB-729 is a single-trigger GalNAc-siRNA targeting all HBV RNA transcripts. The initial treatment response was previously described. At the AASLD Annual Meeting, the researchers reported additional data at the end of treatment and preliminary responses after treatment cessation.

Sixty-five viral suppressed HBeAg-negative CHB patients were randomly assigned to receive VBR + AB-729 + NrtI (n=32), VBR + NrtI (n=16), or AB-729 + NrtI (n=17) for 48 weeks. VBR was administered at 300 mg/day, orally once daily, and AB-729 was administered subcutaneously at 60 mg every 8 weeks. Patients achieving alanine aminotransferase (ALT) <2 times the upper limit of normal + HBV DNA < quantifiable limit (LLOQ) + HBsAg <100 IU/mL based on laboratory results at week 48 could discontinue all treatment drugs and enter the follow-up phase. Patients not meeting these cessation criteria continued NrtI monotherapy during the follow-up. Virological markers included HBsAg (Abbott Architect; LLOQ=0.05 IU/mL) and HBV DNA (Cobas TaqMan; LLOQ=20 IU/mL). Safety was assessed based on adverse events and laboratory parameters.

Results showed that baseline characteristics were similar across treatment groups, and the treatments were well-tolerated. The VBR + AB-729 + NrtI, VBR + NrtI, and AB-729 + NrtI groups had treatment discontinuation rates of 9% (3/32), 6% (1/16), and 6% (1/17) due to adverse events, respectively. Adverse events during treatment were mostly grade 1 or 2, with reported rates of 81% (26/32), 75% (12/16), and 71% (12/17) for the VBR + AB-729 + NrtI, VBR + NrtI, and AB-729 + NrtI groups, respectively. One patient in the VBR + AB-729 + NrtI group experienced a serious adverse event (COVID-19).

Although no patients experienced HBsAg seroconversion, 16/26, 0/15, and 8/10 patients with 48-week data in the VBR + AB-729 + NrtI, VBR + NrtI, and AB-729 + NrtI groups, respectively, met the criteria for discontinuing all treatment. Among these patients meeting cessation criteria, 12 in the VBR + AB-729 + NrtI group and 7 in the AB-729 + NrtI group discontinued all treatment. At 8 weeks after stopping all treatment, 89% (8/9) and 83% (5/6) of patients in the VBR + AB-729 + NrtI and AB-729 + NrtI groups, respectively, maintained continuous suppression of HBsAg <100 IU/mL.

In conclusion, HBeAg-negative CHB patients with viral suppression showed good tolerance to the combination therapy of VBR, NrtI, and AB-729. Existing data suggest that the addition of VBR to AB-729 + NrtI therapy did not significantly improve markers of active HBV infection during or after treatment compared to AB-729 + NrtI treatment alone.

02 At this year’s AASLD conference, researchers, including Jeffrey Wallin from Gilead Sciences, presented findings on the peripheral single-cell gene expression changes in CHB patients responding to Toll-like receptor 8 (TLR8) agonist therapy.

Selgantolimod (SLGN) is an orally administered selective small molecule TLR8 agonist with antiviral potential, demonstrated to be safe and well-tolerated in CHB patients. By detecting Toll-like receptor 8 pathway cytokines such as interleukin (IL)-12p40 and IL-1RA, it was indicated that SLGN could stimulate a robust therapeutic response. Researchers utilized single-cell analysis techniques to explore the molecular impact of SLGN treatment on peripheral blood mononuclear cells (PBMC).

CHB patients received 3 mg of SLGN treatment once a week for 24 weeks. Blood samples were collected from four participants before and 4 hours after administration at baseline, week 11, and week 23. Using the 10X single-cell RNA-seq method, PBMCs were isolated, gene expression was assessed, and analysis was performed using the Seurat R package. Cell types were identified using SingleR. Non-parametric Wilcoxon rank-sum tests were employed to determine differences in gene expression at baseline and various treatment time points.

The results revealed 17 cell clusters through single-cell gene expression analysis. Pathway-level analysis using blood transcription modules (BTM) suggested type I interferon regulation across various cell types at different treatment time points (FDR < 0.01). Following SLGN treatment, interferon-stimulated genes such as IFI144L, STAT1, and MX1 were upregulated in several clusters labeled as B cells, T cells, and NK cells. Additionally, researchers observed the regulation of TLR and inflammatory signaling associated with classical and non-classical monocyte clusters. Among many upregulated genes (FDR < 0.05) identified in classical monocyte clusters, MECP2 and FKBP5 were upregulated at all time points after administration.

These gene products are reported to act as regulators of chromatin structure and gene expression in immune cells (MECP2) and participate in the downregulation of excessive interferon responses (FKBP5). Furthermore, in non-classical monocyte clusters, researchers observed differentially expressed genes (DEG) at the same treatment time points compared to classical monocytes, with overall fold change differences being lower (average log2 fold change of 0.66 vs. 0.49).

It is noteworthy that dynamics of initial T cell DEG were observed to be different from baseline. While hundreds of DEGs were observed in the initial T cell cluster 4 hours after the first application of SLGN, including genes related to STAT3 and NFkB pathways, fewer DEGs were observed at subsequent treatment time points.

In conclusion, the researchers determined substantial changes in gene expression across various cell types in single-cell PBMC analysis of CHB patients treated with SLGN. These findings provide a deeper understanding of cellular changes post-SLGN treatment and may offer information on complementary mechanisms for HBV cure strategies.

03 Polyethylene glycol interferon reduces recurrence after bepirovirsen treatment in CHB patients on nucleos(t)ide analogue therapy: Results from the Phase 2b B-TOGETHER study

At this year’s AASLD conference, researchers, including Maria Buti from Spain, reported the results of the Phase 2b B-TOGETHER study, demonstrating that polyethylene glycol interferon can reduce recurrence in CHB patients on nucleos(t)ide analogue therapy following treatment with bepirovirsen.

In the Phase 2b B-Clear study (209668), bepirovirsen (BPV), an antisense oligonucleotide, administered at 300 mg for 24 weeks to participants maintained on nucleos(t)ide analogue (NA) therapy, achieved a sustained HBsAg and HBV DNA clearance in 9% of patients after 24 weeks of stopping BPV treatment (<quantifiable limit of detection (LLOQ)), with a higher response rate (26%) at the end of BPV treatment. However, some patients experienced recurrence during follow-up. Patients with lower baseline HBsAg had higher response rates (12% and 16% for HBsAg ≤3000 and ≤1000 IU/mL, respectively). The B-Together study evaluated whether sequential treatment with BPV and pegylated interferon (PegIFN) could enhance the observed BPV efficacy in B-Clear.

B-Together is a Phase 2b, multicenter, randomized, open-label study. Patients eligible for inclusion were those on stable NA therapy with HBsAg >100 IU/mL, HBV DNA <90 IU/mL, ALT ≤2 times the upper limit of normal, and no contraindications to PegIFN treatment. Patients were randomized 1:1 to receive BPV 300 mg once weekly (QW, with loading doses on days 4 and 11) for either 24 weeks (Group 1) or 12 weeks (Group 2). After BPV treatment, eligibility was assessed, and patients received 24 weeks of PegIFN treatment at 180 mcg/week, followed by a 24-week (Group 1) or 36-week (Group 2) follow-up. Throughout the study, patients continued NA therapy. The primary endpoint was the proportion of patients with sustained HBsAg and HBV DNA <LLOQ at 24 weeks after planned sequential treatment without restarting antiviral therapy (rescue therapy), with safety assessed by monitoring adverse events.

Results showed that 108 patients were included in the study (55 in Group 1, 53 in Group 2), with similar baseline characteristics between the groups and comparable to B-Clear patients. In Groups 1 and 2, 5 (9%) and 8 (15%) patients, respectively, reached the primary endpoint, all responders having baseline HBsAg ≤3000 IU/mL. Only BPV responders benefited from Peg-IFN treatment, reducing recurrence after discontinuation (recurrence rates for B-Together and B-Clear: 58% vs. 63% for Group 1; 0% vs. 75% for Group 2). The proportions of patients experiencing adverse events were similar in both groups [52 (95%) in Group 1; 52 (98%) in Group 2]. Eight patients (7%) reported severe adverse events [5 during BPV treatment (5%); 0 during PegIFN treatment; 3 during follow-up (3%)]. BPV did not adversely affect the safety of subsequent sequential PegIFN treatment.

In conclusion, the researchers found that sequential treatment with BPV and PegIFN, compared to BPV alone (B-Clear), can reduce recurrence in BPV responders, thereby improving the response rate after discontinuation, with no new safety concerns identified.

04 Evaluation of the effectiveness, safety, tolerability, immunogenicity, and treatment regimen of VTP-300 in combination with low-dose nivolumab in a Phase 2b, open-label study for the treatment of CHB

At this year’s AASLD conference, Henrik Sorensen and colleagues presented the results of a Phase 2b, open-label study evaluating the effectiveness, safety, tolerability, immunogenicity, and treatment regimen of VTP-300 in combination with low-dose nivolumab for the treatment of CHB.

New treatment strategies focus on increasing the functional cure rate of CHB, aiming for the cessation of nucleos(t)ide analogue (NA) therapy without the risk of virological relapse or liver disease progression, further reducing the risk of hepatocellular carcinoma (HCC). Inducing CD8+ T cell responses to HBV may be a necessary mechanism to achieve functional cure. VTP-300 is a novel antigen-specific investigational immunotherapy composed of chimpanzee adenovirus (ChAdOx1) prime and modified Ankara bovine poxvirus (MVA) boost, delivering antigens related to HBV infection. Previous Phase 1b/2a studies in 54 patients suggested that VTP-300, as a monotherapy and in combination with low-dose nivolumab (LDN), can achieve meaningful and sustained HBsAg reductions. This study explores different dosing schedules and boosting regimens to further optimize the efficacy of HBsAg reduction.

The Phase 2b trial is recruiting 120 CHB patients (40 per group) who have received at least 6 months of NA therapy, with HBV DNA viral load ≤1000 IU/mL and HBsAg between 10 and 4000 IU/mL at screening. The first group receives ChAdOx1-HBV (2×10*10 viral particles) on day 29, followed by MVA-HBV (1×10*8 pfu) and LDN (0.3 mg/kg IV); the second group receives ChAdOx1-HBV (2×10*10 viral particles) on day 29, followed by MVA-HBV (1×10*8 pfu) and LDN (0.3 mg/kg IV) on day 85; the third group receives ChAdOx1-HBV (2×10*10 viral particles) on day 29, followed by MVA-HBV (1×10*8 pfu) on day 36 (LDN only if HBsAg ≥10 IU/mL), and MVA-HBV (1×10*8 pfu) on day 85. The primary endpoint is the proportion of patients with HBsAg reduction greater than 1 log at 6 months after starting treatment. During the one-year follow-up, HBV-specific T cell responses are assessed using IFN-gamma ELISpot, covering HBV antigens of genotypes C and D.

As of May 22, 2023, 51 participants have been enrolled in HBV003, with data expected to be reported for at least 50 participants at day 113, showing the impact of the second MVA-HBV boost on HBsAg levels and the effect of LDN at day 36 instead of during MVA-HBV on HBsAg levels. Additionally, at least 40 participants are expected to reach the day 169 time point for the evaluation of NA discontinuation. Patient enrollment is expected to be completed by December 2023, with final results anticipated in early 2025.

In conclusion, VTP-300, as a novel antigen-specific investigational immunotherapy, has shown meaningful and sustained HBsAg reductions in CHB patients when used as monotherapy or in combination with LDN (as observed in the Phase 1b/2a study). Evaluating the addition of PD-1 inhibitors, dosing schedules, and the second MVA-HBV boost is crucial for optimizing the VTP-300 regimen, potentially becoming a key component of functional cure strategies for CHB.

05 Changes in intrahepatic viral and immune markers in CHB patients treated with JNJ73763989 (JNJ-3989) and nucleos(t)ide analogs: Mid-term results at Week 40 from the INSIGHT study

At this year’s AASLD conference, researchers, including Pietro Lampertico from Italy, reported mid-term results at Week 40 from the INSIGHT study, evaluating changes in intrahepatic viral and immune markers in CHB patients treated with JNJ73763989 (JNJ-3989) and nucleos(t)ide analogs (NAs).

The treatment of CHB patients with JNJ-3989 and NA ± JNJ-6379 was shown to significantly reduce serum HBV markers. The INSIGHT study assessed changes in intrahepatic viral and immune markers in CHB patients treated with JNJ-3989-based therapy.

INSIGHT is a Phase 2 multicenter study, including treatment-naive HBeAg-positive CHB patients (Group 1) or HBeAg-negative CHB patients with suppressed virus after NA treatment (Group 2). Patients received 48 weeks of JNJ-3989 + NA treatment (± JNJ-6379 discontinued from the study). Liver biopsy specimens were collected using a standardized procedure at baseline and Week 40 to evaluate changes in intrahepatic viral and immune markers.

Results showed that at baseline, participants in Group 1 had higher levels of viral serum markers than those in Group 2. After 40 weeks of treatment with JNJ-3989, HBsAg levels decreased by 3.78 ± 0.481 log10 IU/mL in Group 1 and 2.40 ± 0.160 log10 IU/mL in Group 2 compared to baseline. One patient (11.1%) in Group 1 achieved HBsAg serum clearance at Week 40. Estimated percentages of HBsAg+ hepatocytes decreased in both groups at Week 40, with only Group 1 showing a decrease in average percentages of HBcAg+ cells. The percentage of HBV RNA+ hepatocytes decreased from 90.2%–100% at baseline to 4.4%–28.4% at Week 40 in Group 1 and from 8.6%–31.6% at baseline to 5.6%–15% at Week 40 in Group 2 (four patients in each group had paired liver biopsy specimens at baseline and Week 40).

During JNJ-3989 treatment, the percentage of cccDNA-/HBV RNA- cells increased from 0–1.2% at baseline to 48.1%–68.9% at Week 40 in Group 1 and from 31.3%–64.8% at baseline to 51.1%–66.7% at Week 40 in Group 2 (four patients in each group had paired liver biopsy specimens at baseline and Week 40). Analysis of liver biopsy specimens revealed an enrichment of early-activated CD8+ T cells in Group 1 and depletion of CD8+ exhausted T cells, CD8+ effector memory T cells, and CD8+ memory stem cells in Group 2 at Week 40.

In conclusion, at Week 40 of JNJ-3989 treatment, there was a reduction in HBsAg+ hepatocytes and an increased proportion of uninfected hepatocytes. Changes in intrahepatic CD8+ T cells occurred during treatment, with early-activated CD8+ T cells increasing in Group 1 and exhaustion of CD8+ T cells occurring in Group 2, suggesting that JNJ-3989 + NA combination therapy can activate adaptive immunity in the liver.

06 Nasal administration of a therapeutic vaccine containing a mucosally adsorbed combination of HBsAg and HBcAg can lead to a long-term reduction of HBsAg levels in patients with chronic HBV infection: 48-month follow-up results.

At this year’s AASLD conference, researchers, including Osamu Yoshida from Ehime University in Japan, reported the 48-month follow-up results of a therapeutic vaccine administered through the nasal cavity containing a mucosally adsorbed combination of HBsAg and HBcAg for the treatment of patients with chronic HBV infection.

The researchers presented a nasal administration therapeutic vaccine containing HBsAg/HBcAg with a mucosally adsorbed excipient carboxyvinyl polymer (CVP-NASVAC), which demonstrated the ability to decrease HBsAg levels in patients with chronic HBV infection. This study evaluated the long-term efficacy after the application of 10 doses of CVP-NASVAC.

The open-label clinical trial conducted at Ehime University Hospital in Japan received approval from the institutional review board (CRB#18EC003) and was registered with the Japanese jRCT Clinical Trials Registry (#jRCTs061180100). Chronic HBV-infected patients were enrolled, and after obtaining informed consent, participants were treated with 10 doses of CVP-NASVAC administered every two weeks, with some patients receiving an additional 10 doses of CVP-NASVAC after a minimum interval of 12 months. The data from participants who completed the 48-month follow-up were analyzed.

Results showed that 72 patients participated in the study, with 61 participants completing the 48-month follow-up, and the analysis was conducted on the data from these participants. During the study, 25 participants continued nucleos(t)ide analogue (NA) therapy, and 40 participants received an additional 10 doses of CVP-NASVAC treatment. After 48 months of applying the initial 10 doses of CVP-NASVAC, 85.2% (n=52/61) of patients demonstrated a decrease in HBsAg compared to baseline, with an average HBsAg reduction of 40.3% (0.4352 Log IU/mL).

Notably, 8 participants achieved HBsAg clearance. Induction of anti-HBs was observed in 70.5% (43/61) of patients after CVP-NASVAC treatment. Following CVP-NASVAC treatment, there was an increase in HBcAg-specific cytotoxic T lymphocytes (CTL). During the 48-month follow-up, 3 out of 9 patients achieved HBeAg clearance. A decrease in HBcrAg was observed in all 24 participants who were tested for HBcrAg at baseline.

In conclusion, the researchers stated that patients with chronic HBV infection, after receiving CVP-NASVAC treatment, showed long-term reduction and clearance of HBsAg. CVP-NASVAC holds promise as a novel immunotherapy for patients with chronic HBV infection.

Reference: Shiraishi K, Imai Y, Sanada T, et al. Long term HBsAg reduction by a nasal administrative therapeutic vaccine containing HBsAg and HBcAg mixed with mucoadhesive CVP in patients with chronic HBV infection: the results of 48 months follow up. AASLD 2023. Oral 52.