Advances in treatment and prevention of hepatitis B

Table 1 Studies addressing hepatitis B testing and diagnosis

Ref.	Study type	Findings
Gao et al[32], 2017	Prospective trial	Higher HBV RNA levels, in NA-treated patients are a predictor of response
		HBV RNA has a strong linear correlation with HBV DNA and HBsAg titer
		HBcrAg and HBV RNA can predict long-term off-therapy HBV virological control in NA-treated patients
Zhang et al[14], 2018	Randomized, controlled, double-blind clinical trial	HBcrAg titers were significantly higher (P < 0.0001) in patients with HBeAg positive HBV. HBsAg titers were directly proportional to necro-inflammatory activity, and inversely proportional to fibrosis
Walsh et al[15], 2019	Prospective trial	HBsAg clearance profile has positive association with HBsAg loss, seroconversion, and response to treatment in patients treated chronically with Adefovir or Tenofovir
Chang et al[34], 2019	Prospective trial	HBcrAg levels reflect liver parenchymal fibrosis progression, and have utility in monitoring hepatic histological changes
Liao et al[35], 2019	Prospective trial	Demonstrated utility of monitoring HBV RNA and HBcrAg levels for NA-treated patients with undetectable HBV DNA
Multiple authors	Prior Studies	HBcrAg has a superior correlation to the decline in HBV DNA levels with anti-viral therapies, and with intrahepatic HBV cccDNA levels[20-23]
		HBcrAg can predict HBV reactivation in immunosuppressed individuals and the development of Hepatocellular Carcinoma[24-28]
		HBV RNA is a pregenomic RNA containing virion that has a similar profile to HBcrAg[16]. Treatment naïve patients with CHB have lower (1-2 logs lower) serum levels of HBV RNA compared to HBV DNA[29,30]

HBsAg: Hepatitis B surface antigen; HBeAg: Hepatitis B e antigen; ALT: Alanine aminotransferase; NA: Nucleos(t)ide analogs; HBV: Hepatitis B virus; HBcrAg: Hepatitis b core-related antigen; cccDNA: Covalently closed circular DNA; CHB: Chronic Hepatitis B.

Table 2 Studies addressing hepatitis B vaccination strategies

Ref.	Study type	Main findings
Koc et al[49], 2018	Prospective open label trial	HBAI20 (HBVaxPro©-10-μg vaccine combined with an adjuvant AI20, a recombinant human IL-2) exhibited protective anti-HBs titers in 90% of previous non-responders likely due to an enhanced immune response
Qiu et al[53], 2018	Prospective trial	Genome wide comparative analysis revealed significant transcriptome and cytokine changes in HBV vaccine non-responders
Da Silva et al[54], 2018	Randomized prospective trial	Impaired seroconversion for HBV vaccination in CKD patients was linked to reduced baseline CXCR3 + CCR6- CXCR5+ memory T cells levels
Van Damme et al[59], 2019	Prospective trial	Immune challenge, in previously vaccinated adults (HBsAg vaccine 2-3 decades prior) showed a 100% anamnestic response by day 30 with significant increase in HBsAg-specific memory B and CD4+ T cells
Raven et al[48], 2020	Open-labeled, randomized, controlled superiority trial	In Immunocompetent non-responders, revaccination with Fendrix 20 μg or HBVaxPro 40 μg resulted in significantly higher response rates compared to HBVaxPro 10 μg, Energix B 20 μg, or Twinrix 20 μg
Chawansuntati et al[63], 2018	Prospective trial	HBV patients with HIV co-infection have reduced levels of TNF-α and IL-2 levels, and may require an increased HBV vaccine dose to counter this problem
Palazzo et al[64], 2018	Prospective trial	Revaccination with the Hepatitis B vaccine (Twinrix, GlaxoSmithKline, London), in HBV patients on maintenance Lenalidomide post autologous hematopoietic stem cell transplant was absolutely safe with 40% efficacy
Nishikawa et al[65], 2020	Prospective trial	For HBV vaccinated, HSCT recipients, 2-year and 3-year cumulative HBV reactivation rates were 22.2% and 28.9% respectively. Discontinuation of immunosuppressants (P = 0.0379) and baseline titers of anti-Hbs (P = 0.004) were related to HBV reactivation

IL-2: Interleukin 2; anti-HBs: Anti Hepatitis B surface antibody; HBsAg: Hepatitis B surface antigen; HIV: Human Immunodeficiency virus; HBV: Hepatitis B virus; TNF: Tumor necrosis factor; HSCT: Hematopoietic stem cell transplant; CKD: Chronic kidney disease.

Table 3 Studies addressing hepatitis B treatment

Ref.	Study type	Findings
Conventional treatment agents
Chuang et al[67], 2018	Prospective study	PEG Interferon at a dose of 180 μg/wk for a duration of 48 wk resulted in better sustained HBeAg seroconversion rates, than in patients with a lower dose and/or shorter treatment duration
Agarwal et al[68], 2018	Randomized controlled trial	96-wk HBV suppression rates were comparable in patients treated with TAF and TDF, for HBeAg positive (73% vs 75%) and HBeAg negative (90% vs 91%) patients
Yim et al[69], 2018	Prospective randomized controlled trial	HBV patients who were partial responders to ETV, fared better (12-mo HBV response, P = 0.022), when switched to TDF versus continuing ETV
Lee et al[70], 2018	Prospective trial	In Lamivudine resistant HBV patients with non-detectable HBV DNA, while on Lamivudine + Adefovir combination therapy, switching to TDF monotherapy yielded non-inferior results at 96-wk
Marcellin et al[71], 2019	Prospective trial	A 10-yr TDF efficacy study showed HBV viral suppression in 100% of HBeAg-negative and 98% in HBeAg positive patients), with few renal or bone-related adverse events, and no resistance to TDF
Cai et al[72], 2019	Multicenter randomized controlled trial	HBV treatment naïve HBeAg positive patients treated with ETV or TDF, showed similar HBV DNA suppression (-6.6485 vs -6.692 log 10 IU/mL, P = 0.807) at 144 wk as well as similar serologic, biochemical, and side-effect profiles
Liang et al[73], 2018	Prospective trial	HBV treatment naïve HBeAg positive patients treated with Telbivudine-based therapy showed a reduction in liver stiffness, monitored by Fibroscan©), from 8.6 at baseline to 6.1 at week 24, and 5.3 at week 104
Liem et al[75], 2019	Randomized controlled trial	In HBV patients who received NA, and achieved HBeAg seroconversion with undetectable HBV DNA, maintenance of remission was seen in 82% of those who continued NA vs 29% of those who discontinued NA
Buti et al[76], 2019	Prospective trial	HBV patients treated with TDF, and then discontinued: At 24 wk following discontinuation of NA, almost a third of patients had grade 3 hepatotoxicity (indicated by AST/ALT of > 5 - < 10 ULN, and total bilirubin of > 3 - < 10 ULN)
Wong et al[77], 2018	Phase II prospective trial	HBV immune-tolerant patients who received TDF and/or Emtricitabine for 4 yr and were followed for another 4 yr after cessation, showed 100% virological relapse at week 4 (HBV DNA > 2000) and a 50% clinical relapse (HBV DNA > 2000 and ALT > 2 ULN) at 15 ± 11 wk
Liem et al[78], 2019	Randomized prospective trial	Randomized addition of PEG-IFN to ETV therapy, in HBeAg positive HBV patients was associated with a significantly higher 48-wk response rate (HBeAg loss), compared to ETV monotherapy (P = 0.03)
Lampertico et al[79], 2019	Prospective randomized controlled trial	Genotype D, HBeAg-negative HBV patients, on NA therapy showed a significant 50% decrease in HBsAg levels, with the addition of PEG-IFN alfa-2a for 48 wk
Chan et al[80], 2019	Prospective trial	In CHB patients, switched to weekly PEG-IFN alfa-2a after seroconversion on entecavir, those with lower HBsAg titers, showed a greater sustained response (88% at HBsAg < 1500 IU/ml and 50% at HBsAg < 500 IU/mL)
Chen et al[82], 2020	Meta-analysis	Confirmed the importance of longer treatment duration and addition of IFN for HBsAg lowering and highlighted the potential value of immune-based therapies
New direct antiviral agents
Ramanan et al[95], 2015	Pre-clinical prospective study	Use of ccc DNA endonucleases (CRISPR/Cas9) resulted in a reduction in both ccc DNA and other parameters of viral gene expression and replication in vitro
Yuen et al[96], 2019	Phase 1 prospective trial	Non-cirrhotic HBeAg-positive CHB patients, tolerated NVR 3-778 (a capsid assembly protein modulator), and showed reduced serum levels of HBV DNA and HBV RNA, to the greatest extent in combination with PEG-IFN
Yuen et al[97], 2020	Phase I, randomized placebo-controlled trial	Demonstrated acceptable safety, pharmacokinetics, and antiviral effects on an investigational HBV core protein inhibitor ABI-H0731
Zhao et al[98], 2019	Phase I, randomized controlled trial	Demonstrated acceptable safety and pharmacokinetics of GLS4 (a novel HBV capsid assembly inhibitor), with or without ritonavir (used to enhance plasma levels of GLS4)
Vandenbossche et al[99], 2019	Phase I double-blind, randomized controlled trial	Demonstrated acceptable safety and pharmacokinetics of JNJ-56136379 (a novel HBV capsid assembly modulator) with more than three times the 90% effective plasma concentration required to inhibit viral replication
Han et al[103], 2019	Phase I double-blind, randomized controlled trial	Demonstrated acceptable safety and pharmacokinetics of GSK3389404 (a liver-targeted antisense oligonucleotide that inhibits the synthesis of hepatitis B surface antigen and all other hepatitis B virus proteins)
New immune based therapies
Boni et al[109], 2018	Phase I prospective trial	Administration of a 12-wk course of GS-9620 (TLR7 agonist) was safe but did not significantly affect serum HBsAg levels. However, it did increase T-cell and NK-cell responses
Janssen et al[110], 2018	Phase II prospective trial	Administration of a 12-wk course of GS-9620 (TLR7 agonist) was safe, demonstrated dose dependent increase in interferon-simulated gene m RNA expression, without IFN-α expression or reduction in HBsAg levels
Agarwal et al[111], 2018	Randomized controlled prospective trial	Addition of Vesatolimod (TLR7 agonist) to Tenofovir in treatment naïve viremic Hepatitis B patients was found to be safe. This intervention led to dose dependent pharmacodynamic induction of ISGs, without significant improvement in HBsAg decline
Han et al[112], 2019	Prospective trial	During YIC treatment, 26 patients with lower IgG galactosylation level at baseline showed (cellular immune response mediated), sustained increase of serum galactosylated IgG and responded to YIC treatment by HBeAg seroconversion
Al Mahtab et al[114], 2018	Open-label phase III trial	Treatment naïve CHB patients showed significantly better controlled HBV DNA, 24 wk post-treatment (P < 0.05) and a lower rate of progression to cirrhosis in the NASVAC group (therapeutic vaccine, containing 100 μg of each HBs and HBc antigens, administered in 2 cycles of 5 doses), versus PEG-IFN alfa 2b (weekly 180 μg)
Lai et al[115], 2018	Randomized controlled prospective trial	In low-level HBsAg CHB patients, serial HBsAg-based vaccinations were safe, resulting in significant HBsAg decline. HLA gene expression and genotypes played a role in vaccine responsiveness
Boni et al[116], 2019	Multicenter phase II prospective randomized controlled trial	Demonstrated improved HBV specific T cell responses, including IFN-γ, TNF-α, and IL-2, with a combined GS-4774 (yeast-based engineered vaccine) and tenofovir versus tenofovir alone
Wu et al[117], 2019	Prospective controlled trial(The HBV Endeavor prospective trial)	HBV patients with confirmed viral suppression and HBsAg loss while on ETV, when switched to immunomodulators (IL-2) and therapeutic vaccines with IFN, showed HBsAg loss in 9.38%, 3.03%, and 3.7% in the IFN/vaccine/IL-2 group, IFN group, and the ETV group, respectively. Higher titer of CD16-NK cells and lower titers of regulatory T cells corresponded to higher response rates of HBsAg loss
Kalkeri et al[142], 2020	Prospective trial	A repurposed compound SRI-32007 demonstrated anti-HBV activity via inhibition of HBV core promoter activity, and might be used in studying therapeutics to manage HBV
Hepatitis B in pregnancy
Cressey et al[120], 2018	Phase III randomized prospective trial	Demonstrated a geometric mean tenofovir AUC (0-24) to be 20% (95%CI: 19%-21%) lower during pregnancy than postpartum, in HBV patients with HIV, should not warrant a dose adjustment (to compensate for the modest reduction in HBV transmission)
Lin et al[121], 2018	Randomized double-blind prospective trial	Initiation of TDF at 24th week of gestation and then 4 weeks after delivery reduced the MTCT from 13.5% (control group) to 0% cervical transmission, in pregnant HBsAg and HBeAg positive patients with high viral loads HBV DNA titer ≥ 2 × 106 IU/mL
Wang et al[122], 2019	Prospective trial	Initiation of TDF at 24th week of gestation revealed a 0.7% MTCT in the ITT group, and 0% in the per protocol group, in pregnant HBsAg and HBeAg positive patients with high viral loads HBV DNA titer > 6 log10 IU/mL
Jourdain et al[123], 2018	Multicenter, double-blind clinical trial	Initiation of TDF at 28th week of gestation till 2 mo postpartum mildly reduced the MTCT from 2% (control group) to 0% cervical transmission, in pregnant HBsAg and HBeAg positive patients with an ALT of < 60. The authors showed that addition of TDF only mildly reduced the MTCT to infants at age 6 mo
Wu et al[125], 2019	Randomized control trial	Immune-tolerant CHB patients awaiting assisted reproduction showed greater viral clearance (90% vs 67.2%, P = 0.002 at week 12, and 96.6% compared to 85.2 % at week 48 respectively) when on a combination of TDF and telbivudine, compared to TDF alone. No difference was noted in the HBeAg seroconversion rates for the two groups (8.3% vs 3.3%; P = 0.233)
Hepatitis B reactivation
Huang et al[127], 2013	Randomized double blind prospective trial	Prophylaxis with ETV significantly reduced HBV reverse seroconversion when compared with placebo in resolved hepatitis B patients receiving Rituximab for lymphoma (4.3% vs 25.9% at 18 mo; P = 0.019)
Kusumoto et al[130], 2019	Prospective trial	Resolved HBV patients with NHL, who received obinutuzumab or rituximab, and followed for HBV reactivation, revealed a strong correlation (P < 0.0001) of HBV reactivation with detectable baseline HBV DNA. Also, Prophylactic NA reduced risk of HBV reactivation (P = 0.0018)
Liu et al[131], 2019	Double bling randomized control trial	Resolved HBV patients with lymphoma who received chemotherapy, had similar reactivation rates with or without ETV prophylaxis (0% vs 3.2%; P = 0.246). Authors suggested that prophylactic use of entecavir was not a cost-effective strategy, especially for those with a baseline positive anti-HBs
Hammond et al[132], 2018	Retrospective study	The incidence of HBV reactivation, in patients on Ibrutinib, was 9.5% (2 out of the 21 patients with known past HBV infection)
Wang et al[135], 2018	Prospective trial	HBV DNA negative patients with HCC who underwent TACE were at risk of HBV reactivation. HBV reactivation rates were significantly lower in those receiving ETV compared with controls (5.9% vs 23.4%; P < 0.05)
Zhang et al[136], 2019	Meta-analysis	HBV DNA negative patients with HCC who underwent TACE were at risk of HBV reactivation (P < 0.01) and hepatitis (P < 0.01). Use of prophylactic anti-viral therapy significantly reduced the risk of HBV reactivation (P < 0.01) and hepatitis (P = 0.02)
Jun et al[137], 2018	Multi-center retrospective study	12.7% of HBV DNA negative patients with HCC who underwent RT had HBV reactivation. Use of prophylactic anti-viral therapy significantly reduced the risk of HBV reactivation (P < 0.001), when compared to the control group. Combined RT and TACE had significant risk for HBV reactivation (P = 0.008)
Liu et al[138], 2020	Retrospective study	CHB patients with SARS-CoV-2 infection had a 15% risk of HBV reactivation

CHB: Chronic hepatitis B; HBV: Hepatitis B virus; HBeAg: Hepatitis B e-antigen; HBV: Hepatitis B virus; HBsAg: Hepatitis B surface antigen; TAF: Tenofovir alafenamide; TDF: Tenofovir disoproxil fumarate; ETV: Entecavir; NA: Nucleos(t)ide analog; TLR7: Toll like receptor 7; YIC: Hepatitis B surface antigen-hepatitis B immunoglobulin immune complex; AST: Aspartate aminotransferase; ALT: Alanine aminotransaminase; PEG-IFN: Pegylated interferon; cccDNA: Covalently closed circular DNA; CRISPR: Clustered regularly, interspaced short palindromic repeats; Cas9: CRISPR associated protein 9; NK: Natural killer; IFN: Interferon; TNF: Tumor necrosis factor; IL-2: Interleukin 2; CD: Cluster of differentiation; HBIG: Hepatitis B immune globulin; AUC: Area under the ROC curve; ROC: Receiver operating characteristic; CI: Confidence interval; ITT: Intention to treat; MTCT: Maternal to child transmission; NHL: Non-Hodgkin’s lymphoma; TACE: Trans-arterial chemoembolization; RT: Radio-therapy; HCC: Hepatocellular carcinoma; GGT: Gamma-glutamyl transferase; ISGs: Interferon stimulated gene transcripts; SARS-CoV-2: Severe acute respiratory syndrome coronavirus 2.