Differential Relapse Patterns After Discontinuation of Entecavir vs Tenofovir Disoproxil Fumarate in Chronic Hepatitis B

Limited Sustained Remission After Nucleos(t)ide Analog Withdrawal: Results From a Large, Global, Multiethnic Cohort of Patients With Chronic Hepatitis B (RETRACT-B Study)

INTRODUCTION

Complete viral suppression with nucleos(t)ide analogs (NAs) has led to a profound reduction in hepatocellular carcinoma and mortality among patients with chronic hepatitis B. Finite therapy yields higher rates of functional cure; however, initial hepatitis B virus (HBV) DNA and alanine aminotransferase (ALT) elevations are almost certain after treatment interruption. We aimed to analyze off-treatment outcomes beyond 12 months after NA cessation.

METHODS

Patients with well-suppressed chronic hepatitis B who were hepatitis B e antigen-negative at NA cessation and remained off treatment without hepatitis B surface antigen (HBsAg) loss at 12 months were included (n = 945). HBV DNA and ALT fluctuations were allowed within the first 12 months. We used Kaplan-Meier methods to analyze outcomes beyond 12 months. Sustained remission was defined as HBV DNA <2,000 IU/mL and ALT <2× upper limit of normal (ULN) and an ALT flare as ALT ≥5× ULN.

RESULTS

Cumulative probability of sustained remission was 29.7%, virological relapse was 65.2% with a mean peak HBV DNA of 5.0 ± 1.5 log 10 IU/mL, an ALT flare was 15.6% with a median peak ALT × ULN of 8.3 (5.7-11.3), HBsAg loss was 9.9% and retreatment was 34.9% at 48 months after NA cessation. A single occurrence of virological relapse or an ALT flare within the first 12 months off-treatment were associated with significantly lower rates of sustained remission beyond 12 months.

DISCUSSION

Despite allowing for HBV DNA and ALT fluctuations within the first 12 months off-treatment, most patients without HBsAg loss did not maintain a sustained response thereafter. The best candidates for NA withdrawal are patients with low HBsAg levels at NA cessation, and those without profound or recurrent virological and biochemical relapses in the first off-treatment year.

Quantitative Measurement of Serum HBcrAg Can Be Used to Assess the Feasibility of Safe Discontinuation of Antiviral Therapy for Chronic Hepatitis B

Hepatitis B virus (HBV) infection is a serious global health problem, and chronic HBV infection significantly increases the risk of liver fibrosis, cirrhosis, and even hepatocellular carcinoma in patients. Current first-line therapeutics such as nucleos(t)ide analogues and interferons are unable to completely clear cccDNA, so the vast majority of patients need to take long-term or even lifelong medication. However, long-term virological and biochemical responses can be achieved in some patients after drug withdrawal. Successfully screening these patients with drug withdrawal advantages is difficult. Hepatitis-B-core-related antigen (HBcrAg) is a new HBV serological marker that which can reflect the level and transcription activity of cccDNA in hepatocytes. Therefore, HBcrAg has potential value in guiding patients in drug withdrawal. This review summarizes previous reports on HBcrAg and evaluates the application value of HBcrAg in safe drug discontinuation.

Nucleos(t)ide analogs for hepatitis B virus infection differentially regulate the growth factor signaling in hepatocytes

BACKGROUND

Recent clinical studies have suggested that the risk of developing HCC might be lower in patients with chronic hepatitis B receiving tenofovir disoproxil fumarate than in patients receiving entecavir, although there is no difference in biochemical and virological remission between the 2 drugs.

METHODS

The effects of nucleoside analogs (NsAs; lamivudine and entecavir) or nucleotide analogs (NtAs; adefovir disoproxil, tenofovir disoproxil fumarate, and tenofovir alafenamide) on cell growth and the expression of growth signaling molecules in hepatoma cell lines and PXB cells were investigated in vitro. The tumor inhibitory effects of NsAs or NtAs were evaluated using a mouse xenograft model, and protein phosphorylation profiles were investigated. The binding of NsAs or NtAs to the insulin receptor (INSR) was investigated by thermal shift assays.

RESULTS

NtAs, but not NsAs, showed direct growth inhibitory effects on hepatoma cell lines in vitro and a mouse model in vivo. A phosphoprotein array revealed that INSR signaling was impaired and the levels of phosphorylated (p)-INSRβ and downstream molecules phosphorylated (p)-IRS1, p-AKT, p-Gab1, and p-SHP2 were substantially reduced by NtAs. In addition, p-epidermal growth factor receptor and p-AKT levels were substantially reduced by NtAs. Similar findings were also found in PXB cells and nontumor lesions of liver tissues from patients with chronic hepatitis B. Prodrug NtAs, but not their metabolites (adefovir, adefovir monophosphate, adefovir diphosphate, tenofovir, tenofovir monophosphate, and tenofovir diphosphate), had such effects. A thermal shift assay showed the binding of NtAs to INSRβ.

CONCLUSIONS

NtAs (adefovir disoproxil, tenofovir disoproxil fumarate, and tenofovir alafenamide), which are adenine derivative acyclic nucleotide analogs, potentially bind to the ATP-binding site of growth factor receptors and inhibit their autophosphorylation, which might reduce the risk of HCC in patients with chronic hepatitis B.

HBV DNA and HBsAg Levels at 24 Weeks Off-Treatment Predict Clinical Relapse and HBsAg Loss in HBeAg-Negative Patients Who Discontinued Antiviral Therapy

BACKGROUND & AIMS

Patients who discontinue nucleo(s)tide analogue therapy are at risk of viral rebound and severe hepatitis flares, necessitating intensive off-treatment follow-up.

METHODS

We studied the association between hepatitis B surface antigen (HBsAg) and hepatitis B virus (HBV) DNA levels at off-treatment follow-up week 24 (FU W24), with subsequent clinical relapse, and HBsAg loss in a multicenter cohort of hepatitis B e antigen (HBeAg)-negative patients with chronic hepatitis B who discontinued nucleo(s)tide analogue therapy.

RESULTS

We studied 475 patients, 82% Asian, and 55% treated with entecavir. Patients with higher HBV DNA levels at FU W24 had a higher risk of clinical relapse (hazard ratio [HR], 1.576; P < .001) and a lower chance of HBsAg loss (HR, 0.454; P < .001). Similarly, patients with higher HBsAg levels at FU W24 had a higher risk of clinical relapse (HR, 1.579; P < .001) and a lower chance of HBsAg loss (HR, 0.263; P < .001). A combination of both HBsAg <100 IU/mL and HBV DNA <100 IU/mL at FU W24 identified patients with excellent outcomes (9.9% clinical relapse and 58% HBsAg loss at 216 weeks of follow-up). Conversely, relapse rates were high and HBsAg loss rates negligible among patients with both HBsAg >100 IU/mL and HBV DNA >100 IU/mL (P < .001).

CONCLUSIONS

Among HBeAg-negative patients with chronic hepatitis B who discontinued antiviral therapy and who did not experience clinical relapse before FU W24, serum levels of HBV DNA and HBsAg at FU W24 can be used to predict subsequent clinical relapse and HBsAg clearance. A combination of HBsAg <100 IU/mL with HBV DNA <100 IU/mL identifies patients with a low risk of relapse and excellent chances of HBsAg loss and could potentially be used as an early surrogate end point for studies aiming at finite therapy in HBV.

Hepatitis Flares or Hepatic Decompensation after Discontinuation of Tenofovir Disoproxil Fumarate and Entecavir in Non-Cirrhotic Hepatitis B e Antigen-Negative Patients

Hepatic events can occur after discontinuing antiviral therapy. We investigated factors associated with hepatitis flares and hepatic decompensation after discontinuing tenofovir disoproxil fumarate (TDF) and entecavir (ETV). Hepatitis flares within 6 months and hepatic decompensation were compared between non-cirrhotic hepatitis B e antigen-negative patients after discontinuing TDF or ETV by using the Cox proportional hazard model. The cumulative rates of hepatitis flare at 6 months after discontinuing ETV and TDF were 2% and 19%, respectively (p < 0.001). The respective rates of hepatic decompensation at 6 months were 0% and 7% (p = 0.009). Higher alanine aminotransferase (ALT) (AASLD criteria) at the end of treatment (EOT) (HR = 4.93; p = 0.001), an off-therapy dynamic change in HBV DNA (rapid rebound of HBV DNA from the nadir, ≥1 log10 IU/mL per month) (HR = 10.7; p < 0.001), and the discontinuation of TDF (HR = 6.44; p = 0.006) were independently associated with hepatitis flares within 6 months. Older age (HR = 1.06; p < 0.001) and an off-therapy dynamic change in HBV DNA (HR = 3.26; p = 0.028) were independently associated with hepatic decompensation after the discontinuation of antiviral therapy. In summary, we demonstrated several factors associated with hepatitis flares and hepatic decompensation after discontinuing antiviral therapy in non-cirrhotic hepatitis B e antigen-negative patients.

Antiviral therapy reduces hepatocellular carcinoma through suppressing hepatitis B virus replication may improve ER stress, mitochondrial and metabolic dysfunctions and decrease p62 in hybridized mice with single HBV transgene and miR-122

Hepatitis B virus (HBV) hijacks autophagy for its replication. Nucleos(t)ide analogs (NUCs) treatment suppressed HBV replication and reduced hepatocellular carcinoma (HCC) incidence. However, the use of NUCs in chronic hepatitis B (CHB) patients with normal or minimally elevated serum alanine aminotransferase (ALT) levels is still debated. Animal models are crucial for studying the unanswered issue and evaluating new therapies. MicroRNA-122 (miR-122), which regulates fatty acid and cholesterol metabolism, is downregulated during hepatitis and HCC progression. The reciprocal inhibition of miR-122 with HBV highlights its role in HCC development as a tumor suppressor. By crossbreeding HBV-transgenic mice with miR-122 knockout mice, we generated a hybrid mouse model with a high incidence of HCC up to 89% and normal ALT levels before HCC. The model exhibited early-onset hepatic steatosis, progressive liver fibrosis, and impaired late-phase autophagy. Metabolomics and microarray analysis identified metabolic signatures, including dysregulation of lipid metabolism, inflammation, genomic instability, the Warburg effect, reduced TCA cycle flux, energy deficiency, and impaired free radical scavenging. Antiviral treatment reduced HCC incidence in hybrid mice by approximately 30-35% compared to untreated mice. This effect was linked to the activation of ER stress-responsive transcription factor ATF4, clearance of autophagosome cargo p62, and suppression of the CHOP-mediated apoptosis pathway. In summary, this study suggests that despite minimal ALT elevation, HBV replication can lead to liver injury. Endoplasmic reticulum stress, reduced miR-122 levels, mitochondrial and metabolic dysfunctions, blocking protective autophagy resulting in p62 accumulation, apoptosis, fibrosis, and HCC. Antiviral may improve the above-mentioned pathogenesis through HBV suppression.

Safety considerations for withdrawal of nucleos(t)ide analogues in patients with chronic hepatitis B: First, do no harm

Nucleos(t)ide analogues (NA) are widely used to treat hepatitis B virus (HBV) infection, but they cannot eradicate the virus and treatment duration can be lifelong if the endpoint is set at seroclearance of the hepatitis B surface antigen (HBsAg). As an alternative strategy, finite NA therapy without the prerequisite of HBsAg seroclearance has been proposed to allow treatment cessation in patients with sustained undetectable HBV viremia for two to three years. However, reactivation of viral replication almost always follows NA withdrawal. Whereas HBV reactivation might facilitate HBsAg seroclearance in some, it could lead to serious acute flare-ups in a certain proportion of patients. Occurrence and consequences of NA withdrawal flares are complicated with various factors involving the virus, host, and treatment. Accurate risk prediction for severe flares following NA cessation is essential to ensure patient safety. The risks of life-threatening flares in patients who discontinued NA according to the stopping rules of current guidelines or local reimbursement policies have recently been quantitatively estimated in large-scale studies, which also provided empirical evidence to help identify vulnerable patients at risk of devastating outcomes. Moreover, risk predictors were further explored and validated to hopefully aid in patient selection and management. In this narrative review with a focus on patient safety, we summarize and discuss current literature on the incidence of severe flares following NA cessation, risk stratification for candidate selection, rules of posttreatment monitoring, and indications for treatment resumption. We also share our thoughts on the limitations of existing knowledge and suggestions for future research.

Letter: Safety after cessation of nucleos(t)ide analogue therapy in patients with chronic hepatitis B infection-Authors' reply

This article is linked to Hsu et al papers. To view these articles, visit https://doi.org/10.1111/apt.17614 and https://doi.org/10.1111/apt.17657

Higher rate of HBsAg loss after discontinuation of tenofovir than entecavir in patients with chronic hepatitis B

BACKGROUND/AIMS

To compare the rates of hepatitis B surface antigen (HBsAg) loss after discontinuation of entecavir versus tenofovir disoproxil fumarate (TDF) in patients with chronic hepatitis B (CHB) without cirrhosis.

METHODS

A total of 891 patients who received entecavir (n = 556) or TDF (n = 335) followed up post-treatment for at least 12 months were retrospectively assessed. A total of 677 patients who had continued entecavir or TDF therapy for at least 4 years were enrolled as the continued group.

RESULTS

Patients who discontinued TDF had higher rates of virological and clinical relapse and retreatment than patients who discontinued entecavir in both the HBeAg-positive and HBeAg-negative subgroups. In the entire discontinued cohort, the cumulative rates of HBsAg loss at 7 years were 22.6% and 35.4% in the entecavir and TDF groups respectively. Patients who discontinued TDF had significantly higher rates of HBsAg loss than patients who discontinued entecavir therapy in all (p = 0.019) and propensity score-matched (p = 0.015) patients, especially among the subgroups who achieved a sustained response (p < 0.001). Cox regression analysis revealed that TDF, longer treatment duration and lower HBsAg levels at end of treatment were independently associated with HBsAg loss in the entire discontinued group. The incidence of HBsAg loss was significantly higher in the discontinued group than in the continued group after propensity score matching (p < 0.001), including HBeAg-positive and HBeAg-negative patients.

CONCLUSIONS

Patients who discontinued TDF had significantly higher rates of HBsAg loss than patients who discontinued entecavir, especially among the subgroups without HBV relapse after cessation of therapy.

Hepatocellular carcinoma risk in patients with chronic hepatitis B receiving tenofovir- vs. entecavir-based regimens: Individual patient data meta-analysis

BACKGROUND & AIMS

The comparative risk of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB) receiving tenofovir disoproxil fumarate (TDF) vs. entecavir (ETV) remains controversial. In this individual patient data (IPD) meta-analysis, we aimed to compare HCC risk between the two drugs and identify subgroups who may benefit more from one treatment than the other.

METHODS

Published meta-analyses, electronic databases and congress proceedings were searched to identify eligible studies through January 2021. We compared HCC risk between the two drugs using a multivariable Cox proportional hazards model with anonymised IPD from treatment-naïve patients with CHB receiving TDF or ETV for ≥1 year. Treatment effect consistency was explored in propensity score matching (PSM), weighting (PSW) and subgroup analyses for age, sex, hepatitis B e-antigen (HBeAg) positivity, cirrhosis and diabetes status.

RESULTS

We included 11 studies from Korea, Taiwan and Hong Kong involving 42,939 patients receiving TDF (n = 6,979) or ETV (n = 35,960) monotherapy. Patients receiving TDF had significantly lower HCC risk (adjusted hazard ratio [HR] 0.77; 95% CI 0.61-0.98; p = 0.03). Lower HCC risk with TDF was consistently observed in PSM (HR 0.73; 95% CI 0.59-0.88; p <0.01) and PSW (HR 0.83; 95% CI 0.67-1.03; p = 0.10) analyses and in all subgroups, with statistical significance in the ≥50 years of age (HR 0.76; 95% CI 0.58-1.00; p <0.05), male (HR 0.74; 95% CI 0.58-0.96; p = 0.02), HBeAg-positive (HR 0.69; 95% CI 0.49-0.97; p = 0.03) and non-diabetic (HR 0.79; 95% CI 0.63-1.00; p <0.05) subgroups.

CONCLUSION

TDF was associated with significantly lower HCC risk than ETV in patients with CHB, particularly those with HBeAg positivity. Longer follow-up may be needed to better define incidence differences between the treatments in various subgroups.

IMPACT AND IMPLICATIONS

Previous aggregate data meta-analyses have reported inconsistent conclusions on the relative effectiveness of tenofovir disoproxil fumarate and entecavir in reducing hepatocellular carcinoma risk in patients with chronic hepatitis B (CHB). This individual patient data meta-analysis on 11 studies involving 42,939 patients from Korea, Taiwan and Hong Kong suggested that tenofovir disoproxil fumarate-treated patients have a significantly lower hepatocellular carcinoma risk than entecavir-treated patients, which was observed in all subgroups of clinical interest and by different analytical methodologies. These findings should be taken into account by healthcare providers when determining the optimal course of treatment for patients with CHB and may be considered in ensuring that treatment guidelines for CHB remain pertinent.