Efficacy of switching to entecavir monotherapy in Japanese lamivudine-pretreated patients

Sequential therapy from entecavir to tenofovir alafenamide versus continuous entecavir monotherapy for patients with chronic hepatitis B

Background and Aim

Although tenofovir alafenamide (TAF), as well as entecavir (ETV), is widely used as first‐line treatment for patients with chronic hepatitis B, there are only a few studies comparing sequential therapy from ETV to TAF and continuous ETV monotherapy in patients with maintained virologic response to ETV.

Methods

In a retrospective multicenter study, we investigated the efficacy and safety of sequential therapy from ETV to TAF (ETV‐TAF group) and compared them with continuous ETV monotherapy (ETV group), using propensity score matching, in chronic hepatitis B patients.

Results

From 442 patients, we analyzed 142 patients from each group comprising 71 patients matched for several data, including age, HBV genotype, hepatitis B envelope antigen, cirrhosis, alanine aminotransferase, platelet count, prior ETV monotherapy period, and hepatitis B surface antigen (HBsAg) change during prior ETV monotherapy. In the ETV‐TAF group, HBsAg levels significantly decreased from baseline to 48 weeks after switching to TAF (−0.02 log IU/mL, P = 0.038). HBcrAg levels also significantly decreased after switching to TAF (−0.1 log IU/mL, P = 0.004). However, there were no significant differences in the reduction of HBsAg and HBcrAg levels between the ETV‐TAF and ETV groups. There was no significant difference in the change of estimated glomerular filtration rate levels from baseline to 48 weeks between the two groups.

Conclusions

The present study indicated that the efficacy, especially of the HBsAg‐reducing action, and safety of sequential therapy from ETV to TAF were similar to those of continuous ETV monotherapy among chronic hepatitis B patients with maintained virologic response to ETV.

Reduced Incidence of Hepatocellular Carcinoma in Cirrhotic and Noncirrhotic Patients With Chronic Hepatitis B Treated With Tenofovir-A Propensity Score-Matched Study

Background

The effect of newer oral anti-hepatitis B virus (HBV) medication, tenofovir disoproxil (TDF), on liver-related outcomes among Asians is limited. We examined the effect of TDF on the incidence of hepatocellular carcinoma (HCC) in an Asian population with chronic hepatitis B (CHB).

Methods

This was a retrospective cohort study of 6914 adults with chronic HBV monoinfection and no history of transplantation who were recruited from 6 US referral, community medical centers and a community based Taiwan cohort for a total of 774 patients who received TDF and 6140 who were not treated. Propensity score matching (PSM) for age, sex, HBV e antigen status, HBV DNA level, alanine aminotransferase (ALT) level, baseline cirrhosis status, and follow-up time was performed to balance the groups, resulting in 591 treated individuals and 591 untreated individuals. Kaplan-Meier analysis was used to estimate the cumulative risk of HCC. Cox proportional hazards models were run to estimate the HCC risk between groups.

Results

The 8-year cumulative HCC incidence was significantly higher in the PSM untreated group (20.13% vs 4.69%; P < .0001). Cirrhosis was a significant predictor for HCC (adjusted hazard ratio [aHR], 5.36; 95% confidence interval [CI], 2.73-10.51; P < .001). On multivariate analysis adjusted for age, sex, HBV DNA level, ALT level, and study site, TDF was associated with a 77% reduction in the risk of HCC (aHR, 0.23; 95% CI, .56-.92) in patients with cirrhosis and a 73% reduction (aHR, 0.27; 95% CI, .07-.98) in patients without cirrhosis.

Conclusions

Among cirrhotic and noncirrhotic Asian patients with CHB, TDF therapy was significantly associated with a reduction in the 8-year HCC cumulative incidence rate.

Impact of prior lamivudine use on the antiviral efficacy and development of resistance to entecavir in chronic hepatitis B patients

Background/Aims

To determine the efficacies of entecavir (ETV) in nucleos(t)ide analogue (NA)-naïve chronic hepatitis B (CHB) patients and in those with prior lamivudine (LAM) use who did not develop resistance.

Methods

We retrospectively enrolled 337 patients with CHB who were treated with ETV (0.5 mg daily) for at least 30 months. The study included 270 (80.1%) NA-naïve patients and 67 (19.9%) LAM-use patients. Ten of the LAM-use patients were refractory to LAM therapy without developing resistance.

Results

Genotypic resistance to ETV developed more frequently in the LAM-use group (13.1%) than in the NA-naïve group (2.6%) at 60 months (P=0.009). In subgroup analysis, after excluding the 10 patients who were refractory to LAM therapy, the cumulative probability of ETV resistance did not differ significantly between the two groups (P=0.149). Prior LAM refractoriness and a higher hepatitis B virus DNA level at month 12 were independent predictive factors for the development of ETV resistance.

Conclusions

ETV resistance developed more frequently in LAM-use patients with CHB. However, prior LAM use without refractoriness did not affect the development of ETV resistance. The serum hepatitis B virus DNA level at month 12 was a major predictor for the development of ETV resistance.

Current and future directions for treating hepatitis B virus infection

Hepatitis B virus (HBV) persistently infects approximately 350 million people, and approximately 600000 liver-related deaths are observed per year worldwide. HBV infection is also one of the major risk factors for hepatocellular carcinoma (HCC). The persistence of serum hepatitis B e antigen (HBeAg) and high level of serum HBV DNA are thought to reflect a high HBV replication status in hepatocytes, causing cirrhosis, HCC and liver-related deaths. It has been reported that antiviral therapy, such as peginterferon and nucleos(t)ide analogues (NUCs), could suppress liver-related death by inhibiting the HBV DNA levels and inducing seroconversion from HBeAg to antibody to HBe antigen. Currently, peginterferon is widely used, but there are also several disadvantages in the use of peginterferon, such as various adverse events, the administration route and duration. It is difficult to predict the effects of treatment and interferon is contraindicated for the patients with advanced fibrosis of the liver and cirrhosis. With respect to NUCs, entecavir and tenofovir disoproxil fumarate are current the first-choice drugs. NUCs can be administered orally, and their anti-viral effects are stronger than that of peginterferon. However, because cessation of NUC administration leads to high levels of viral replication and causes severe hepatitis, they must be administered for a long time. On the other hand, the use of both interferon and NUCs cannot eliminate covalently closed circular DNA of HBV. In this review, we evaluate the natural course of chronic HBV infection and then provide an outline of these representative drugs, such as peginterferon, entecavir and tenofovir disoproxil fumarate.

A novel estimation of the relative economic value in terms of different chronic hepatitis B treatment options

Background

Prescribers, payors and healthcare decision-makers are increasingly examining the value of treatments. This study aims at analyzing economic value of chronic hepatitis B (CHB) treatment options, which are available in Korea.

Methods

CHB infection was simulated using a health-state transition model with disease states defined as mild disease (Ishak F0/F1), fibrosis (F2/F3/F4), advanced fibrosis/cirrhosis (>F4), and complicated disease states (decompensated cirrhosis, hepatocellular carcinoma, liver transplant and death) based on available natural history data. The value of treatment-specific attributes on disease progression/regression was estimated based on published data in terms of events and costs avoided. 5-year treatment duration was assumed except for treatment initiation. Primary model output is the estimated cost savings of entecavir per patient per day of treatment versus the comparator in question for a given CHB patient.

Results

The simulation of treating with entecavir versus no treatment predicted improved clinical outcomes for entecavir-treatment patients. In the long term, these clinical benefits translate into cost savings of $3.10 per day of treatment. In naive patient treatment, daily cost savings of using entecavir versus lamivudine or telbivudine was estimated at $2.89 and $1.72, respectively. In the case of suboptimal responders who pre-treated with lamivudine, daily cost saving for patients switching to entecavir was $1.38 per day of treatment compared to patients maintaining on lamivudine.

Conclusions

Entecavir exhibits characteristics of a favourable CHB treatment, which directly translates into economic and therapeutic value as opposed to either no treatment or alternative strategies.

Hepatitis B e antigen predicts delayed reduction of HBV DNA without viral breakthrough with adefovir dipivoxil and lamivudine: a 5-year study of patients with hepatitis B with lamivudine resistance

To clarify the factors associated with delayed reduction of HBV DNA during combination treatment with adefovir dipivoxil (ADV) and lamivudine (LAM) for patients with LAM-resistant hepatitis B virus (HBV), factors including patient characteristics, viral mutations, and drug metabolism were investigated during a 5-year observation period. Delayed reduction of HBV DNA was defined as delayed viral response of detectable HBV DNA after 3 years of combination therapy. Of 67 consecutive patients, 47 attained undetectable HBV DNA after 3 years of combination therapy, and the mean therapeutic duration was 5 years (range: 3.0-8.4 years). The patients with delayed viral response had high levels of HBV DNA and HBe antigen, while those with negative or low levels of HBe antigen were also negative for HBV DNA, even if they had high levels of HBV DNA. In the multivariate analysis with the proportional hazards model, a high baseline level of HBe antigen was negatively associated with viral decline to an undetectable level (P = 0.013). A higher baseline of HBe antigen corresponded to a lower annual decline in HBV DNA (R = -0.38, P = 0.004). No patients showed ADV-resistant mutations in the HBV reverse transcriptase region. Trough concentrations of LAM and ADV showed no clear associations with viral response. HBe antigen levels at the initiation of therapy, and reductions in these levels during therapy are predictive of the therapeutic response to combination therapy with ADV and LAM for patients with LAM-resistant HBV.

Current Nucleos(t)ide Analogue Therapy for Chronic Hepatitis B

Although the prevalence of chronic hepatitis B has decreased considerably in recent years due to widespread use of the hepatitis B virus (HBV) vaccine, its prevalence still remains high in adults, and this can place a significant burden on health care in areas with endemic HBV. Since the introduction of nucleos(t)ide analogues (NUCs), there has been marked improvement in the care of patients with chronic hepatitis B, resulting in increased survival. However, the emergence of drug resistance in patients treated with NUCs is a major concern. The number of multi-drug resistant patients is increasing, and many patients may not respond to the currently available drugs. In this review, we describe the current status of NUC therapy for antiviral-naïve and -resistant patients.

Recommendation of lamivudine-to-entecavir switching treatment in chronic hepatitis B responders: Randomized controlled trial

AIM

  In the 2007-2008 guidelines of the study group (Ministry of Health, Labor and Welfare of Japan), lamivudine (LAM)-continuous treatment was recommended in patients treated with LAM for more than 3 years who maintained hepatitis B virus (HBV) DNA less than 2.6 log copies/mL, because in these patients LAM resistance might exist and switching treatment to entecavir (ETV) might cause ETV resistance. However, there was no evidence on whether switching treatment to ETV- or LAM-continuous treatment was better in those patients. In the present study, we performed a randomized controlled trial of LAM-to-ETV switching treatment.

METHODS

  Twenty-seven patients treated with LAM for more than 3 years whose HBV DNA levels were less than 2.6 log copies/mL were enrolled and randomly divided into two groups, LAM-continued group or switching to ETV group. Then, we examined incidence of virological breakthrough (VBT) and breakthrough hepatitis (BTH) in each group.

RESULTS

  There was no BTH in any of the patients. VBT was observed in six patients of the LAM group (6/15, 40%), and no patient of the ETV group (0/11, 0%) (P = 0.02). The differences of the proportion of cumulated VBT using a log-rank test with Kaplan-Meier analysis were significant between the LAM and ETV groups (P = 0.025).

CONCLUSION

  In patients treated with LAM for more than 3 years maintaining HBV DNA less than 2.6 log copies/mL, switching treatment to ETV is recommended at least during the 2 years' follow-up period.

Rapid detection of drug-resistant mutations in hepatitis B virus by the PCR-Invader assay

Early detection of resistant mutations of hepatitis B virus (HBV) is important for patients on nucleos(t)ide analog therapy. An assay based on the PCR-Invader technology was developed to detect resistant mutations with high sensitivity. The assay specifically detects mutations at codons 180, 181, 184, 202, 204, and 250 of the HBV polymerase reverse transcriptase domain. These mutations result in resistance to lamivudine and entecavir. In mixtures of plasmids containing wild-type and resistant mutants, fold-over-zero values for resistant mutations were detected in 2% of the total. Seventy-five serum samples from patients, whose treatment had been switched from lamivudine to entecavir, were examined by the PCR-Invader assay and direct sequencing. The PCR-Invader assay detected all resistant mutations that were detected by direct sequencing and even detected the presence of mutants that direct sequencing could not. Cloning sequencing confirmed those mutations found by the PCR-Invader assay and not by direct sequencing. The PCR-Invader assay is a useful tool for the early detection of drug-resistant mutations.