Viral kinetics in patients with lamivudine-resistant hepatitis B during adefovir-lamivudine combination therapy

The ultra-short virological dynamics in response to entecavir or lamivudine during chronic hepatitis B with spontaneous severe acute exacerbation

BACKGROUND

Nucleoside/nucleotide analogue (NA) therapy could be life-saving in chronic hepatitis B (CHB) with spontaneous severe acute exacerbation (SAE). We aimed to investigate the ultra-short virological responses to NA.

METHODS

We conducted a randomized controlled trial in which CHB patients with spontaneous SAE were randomized to receive lamivudine (LVD) or entecavir (ETV) between July 2012 and April 2016 (ClinicalTrials.gov: NCT01627223). The serum HBV viral loads on day 1 (baseline), 3, 5, 8, 15, 22, 29, 85 and 180 after initiating NA therapy were checked and analysed.

RESULTS

In total, 17 patients (7 in LVD and 10 in ETV group) were recruited, and 3 patients (17.7%) died or received liver transplantation due to hepatic failure. The median (IQR) HBV DNA decline on days 3, 5, 8, 15, 22, 29, 85 and 180 were 1.38 (1.09-1.50), 2.36 (1.89-2.58), 3.19 (2.21-3.51), 3.76 (2.54-4.40), 3.43 (2.44-4.75), 4.00 (3.01-5.04), 5.00 (3.61-6.21) and 6.50 (4.12-7.20) log IU/ml, respectively. The baseline characteristics were basically similar between the two groups, and the dynamic changes in HBV DNA were not significantly different between the two groups. Further analysis of the patients with high HBV viral load (>6 log IU/ml) revealed that a similar baseline HBV DNA level in the two groups (LVD versus ETV: median 8.0 [7.5-8.8] versus 7.7 [6.6-8.4] log IU/ml; P=0.45), and the dynamic changes of HBV DNA were very similar.

CONCLUSIONS

CHB with spontaneous SAE responded similarly to treatment using either LVD or ETV, with both drugs inducing a rapid decline of HBV viral load.

Combination versus sequential monotherapy in chronic HBV infection: a mathematical approach

Sequential monotherapy is the most widely used therapeutic approach in the treatment of hepatitis B virus (HBV) chronic infection. Unfortunately, under therapy, in some patients the hepatitis virus mutates and gives rise to variants which are drug resistant. We wonder whether those patients would have benefited from the choice of combination therapy instead of sequential monotherapy. To study the action of these two therapeutic approaches and to explain the emergence of drug resistance, we propose a stochastic model for the infection within a patient who is treated with two drugs, either sequentially or contemporaneously, and who, under the first kind of therapy develops a strain of the virus which is resistant to both drugs. Our stochastic model has a deterministic approximation which is a slight modification of a classic three-strain model. We discuss why stochastic simulations are more suitable than the study of the deterministic approximation, when modelling the rise of mutations (this is mainly due to the amplitude of the stochastic fluctuations). We run stochastic simulations with suitable parameters and compare the time when, under the two therapeutic approaches, the resistant strain first reaches detectability in the serum viral load. Our results show that the best choice is to start an early combination therapy, which allows one to stay drug resistance free for a longer time and in many cases leads to viral eradication.

Early Viral Kinetics with Telbivudine, Tenofovir or Combination of Both in Immunotolerant Patients with Hepatitis B e Antigen-Positive Chronic Hepatitis B

Introduction

Viral kinetics has proved useful in understanding antiviral potency, determining antiviral profiles and optimizing treatment strategy.

Methods

This was a randomized, open-label study comparing the viral kinetics in 46 hepatitis B e antigen-positive patients during 12-week treatment with telbivudine monotherapy, tenofovir monotherapy or the combination of telbivudine plus tenofovir. A standard biphasic mathematical model was used to compare hepatitis B virus (HBV) DNA decay parameters.

Results

Forty-six patients received telbivudine (n = 16), tenofovir (n = 14) or telbivudine plus tenofovir (n = 16). From baseline to Week 12, the mean (SD) reduction in HBV DNA levels was not significantly different between treatment groups: −3.9 (0.9) log₁₀ copies/mL in telbivudine group, −4.2 (0.7) log₁₀ copies/mL in tenofovir group, and −4.4 (1.0) log₁₀ copies/mL in combination group. No significant difference was observed among the three groups for viral clearance rate per day (0.97, 1.02, and 0.88, respectively) or for infected cell loss rate per day (0.04, 0.05, and 0.05, respectively). Antiviral efficiency in blocking viral production was similar in the monotherapy groups (median; 99.7% in telbivudine group and 99.4% in tenofovir group), but was slightly better and more homogeneous in the combination treatment group than in the monotherapy groups: mean (SD), 99.1% (0.8%) and 98.8% (1.6%), respectively (Wald–Wolfowitz test; P = 0.038). All treatments were well tolerated and no serious adverse event was reported during the study. Of the 46 patients in the safety population, 23 experienced adverse events. Most of the adverse events were not suspected to be related to the study drug by the investigators.

Conclusion

Monotherapy with telbivudine or tenofovir showed similar antiviral effectiveness in HBV DNA reduction and viral kinetics of HBV DNA decay. Efficiency in blocking viral production was slightly improved in the combination treatment group compared to the monotherapy groups.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-014-0039-5) contains supplementary material, which is available to authorized users.

Hepatitis B virus kinetics under antiviral therapy sheds light on differences in hepatitis B e antigen positive and negative infections

BACKGROUND

Hepatitis B e antigen (HBeAg)–negative chronic hepatitis B infection has a presentation and clinical course that is divergent from that of HBeAg‐positive infection. The former usually presents with lower viral levels but faster progression to liver disease. We sought to better understand the balance between replication and the immune response against hepatitis B virus (HBV).

METHODS

Viral kinetics in 50 HBeAg‐negative patients under various treatment protocols with interferon α and/or nucleoside or nucleotide analogs was analyzed. HBV DNA level was measured frequently and the data fitted to a viral dynamic model. A meta‐analysis of all published studies of viral kinetics in HBeAg‐positive and HBeAg‐negative infection was also conducted.

RESULTS

We found that the clearance of both HBV virions and infected cells was significantly faster in HBeAg‐negative infection than in HBeAg‐positive infection. In HBeAg‐negative infection, there was also a negative correlation between baseline HBV DNA levels and infected cell half‐life, suggesting that the higher the viral load the faster the turnover of infected cells.

CONCLUSIONS

These results reveal the dual role played by the immune response in maintaining lower viral levels and inducing faster turnover of infected cells, the latter of which may be responsible for the more aggressive nature of HBeAg‐negative infection.

Early viral kinetics of telbivudine and entecavir: results of a 12-week randomized exploratory study with patients with HBeAg-positive chronic hepatitis B

We characterized the early viral kinetic profiles of telbivudine and entecavir and the effects of these potent nucleoside analogs on hepatitis B virus (HBV) DNA and alanine aminotransferase levels in adults with hepatitis B e antigen-positive compensated chronic hepatitis B. Forty-four patients were enrolled in this open-label, parallel-group, multicenter study and randomized to receive telbivudine or entecavir for 12 weeks. Reductions in hepatitis B virus DNA and alanine aminotransferase levels from baseline to weeks 2, 4, 8, and 12 were assessed. Viral kinetic parameters, including viral clearance per day, loss of infected cells per day, and efficiency of inhibition of viral production, were estimated by using a biphasic mathematical model. Statistical analyses were limited to descriptive analyses. The 2 treatment groups achieved similar reductions in HBV DNA and alanine aminotransferase levels. Mean reductions in levels of hepatitis B virus DNA at week 12 were 6.6 +/- 1.6 and 6.5 +/- 1.5 log(10) copies/ml for the telbivudine- and entecavir-treated patients, respectively. There were no significant differences between groups in values for mean viral clearance per day, mean loss of infected cells per day, or efficiency of blocking viral production. The safety profiles for both medications were favorable. During the first 12 weeks of treatment, telbivudine and entecavir demonstrated similar antiviral potencies, resulting in a rapid and profound suppression of serum hepatitis B virus DNA and reduction of alanine aminotransferase levels. No differences in the effects of these 2 agents on early viral kinetics were observed. Both medications were well tolerated.

Management of hepatitis B virus reactivation in patients with hematological malignancies treated with chemotherapy

INTRODUCTION

Hepatitis B virus (HBV) reactivation is a major cause of morbidity and mortality in patients with hematological malignancies who receive cytotoxic chemotherapy. We have therefore carried out a prospective observational study out to assess the incidence, prevalence, and clinical course ina cohort of these patients.

METHODS

HBV and HCV markers and liver function indices were monitored prospectively in 318 consecutive patients(171 males, 147 females; mean age 57 years) with hematological malignancies, who had been referred to the Hematology Division, Perugia University, between October 2005 and March 2007 and followed up for at least 6 months.

RESULTS

At diagnosis, 32 patients (10%) had received HBV vaccination; 30 were responders. At least one HBV marker was positive in 70/318 patients (22%): 14 (20%) were HBsAg-positive(HBV surface antigen-positive), 13 (19%) were only anti-HBc positive (antibodies to HB core antigen), and 43(61%)were anti-HBc and anti-HBs positive. Twelve HBsAg+ patients received nucleoside/nucleotide analogs (adefovir [six patients],lamivudine [four], and combined adefovir/lamivudine[two non-responders to lamivudine]). After 6 months of therapy, HBV-DNA was negative and transaminases were normal in nine of these 12 patients (adefovir [six], lamivudina[two], adefovir + lamivudina [one]). Seroreversion was achieved in 3/13 patients (23%) who were only anti-HBc positive;all were on rituximab therapy and received adefovir. Seroreversion was not observed in any of the 43 patients who were anti-HBc- and anti-HBs positive.

CONCLUSIONS

Essential to the management of patients with hematological malignancies undergoing chemotherapy are surveillance and prophylaxis of HBV infection together with prompt administration of nucleoside/nucleotide analogs in cases of reactivation and/or seroreversion.

Anti-hepatitis B virus treatment guided by long-term virus kinetics stepwise tracing

BACKGROUND AND AIMS

Biphasic modeling of viral kinetics provided valuable information to rapidly assess potential antiviral regimens during the beginning of therapy, but has not been performed over the long term.

METHODS

In 11 chronic hepatitis B patients with lamivudine treated per day, the model with delay time was applied to examine phase transition and analyze viral kinetics parameters.

RESULTS

Viral decay conformed to a biphasic mode during the first 4 weeks, with the complex profile appeared in the later period. Lamivudine treatment resulted in a mean log hepatitis B virus (HBV)-DNA decline of 1.77 +/- 0.55 after 4 weeks and 3.79 +/- 1.70 log after 24 weeks. The median effectiveness of blocking viral replication was 96% (range, 89-99%). The median rate of free virus clearance and infected cell loss was 1.1/day and 0.03/day, respectively. Through phase transition determination and stepwise modeling process, viral kinetics were evaluated for complex decay profile during long-term therapy. Moreover, with the abnormal kinetics tracked, an occasion of add-on combined therapy was developed to treat patients with emerging virus mutants.

CONCLUSION

The present study using mathematical modeling of viral decay may be a useful approach to evaluate optimal individualized therapy for HBV infection in a continuous long-term manner.

Serum HBsAg changes in HBeAg positive chronic hepatitis B patients with continuous viral load reductions during treatment with adefovir or peg-interferon-alpha-2a

Hepatitis B surface antigen (HBsAg) loss under antiviral therapy is rare in chronic hepatitis B patients and the dynamics of serum HBsAg in these patients are not available. The changes in serum HBsAg following treatment with adefovir (n=31) or peg-interferon-alpha-2a (n=23) were studied in hepatitis B e-antigen (HBeAg) positive chronic hepatitis B patients. Abbott Architect HBsAg assay was used to quantify serum HBsAg. HBsAg levels were significantly decreased during the first 12 weeks of treatment with median change of -397.0 IU/ml and -555.4 IU/ml, respectively for adefovir and peg-interferon-alpha-2a (p=0.005 and 0.001, respectively). Beyond 12 weeks, no further significant HBsAg reductions were found even in patients with sustained viral replication inhibition in either group. Three distinct patterns of HBsAg changes were observed in most patients in both treatment groups: biphasic pattern (rapid HBsAg reduction from baseline to week 12); assurgent pattern (higher HBsAg level at week 12 than at baseline); and wavy pattern (HBsAg reduction from baseline to week 12, followed by relapse at week 24 or week 28). These results might offer insights into the possible mechanism(s) underlying the unusual occurrences of HBsAg loss under antiviral therapy.

Virodynamic Predictors of Response to Pegylated Interferon and Lamivudine Combination Treatment of Hepatitis B e Antigen-Positive Chronic Hepatitis B

Background

Early identification of non-responders to interferon-α and development of stopping rules are needed in patients with chronic hepatitis B to reduce treatment-related costs and morbidity.

Methods

In total, 47 patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B received pegylated interferon-α2b for 8 weeks, lamivudine plus pegylated interferon-α2b combination therapy for 24 weeks and lamivudine monotherapy for 28 weeks. Sustained virological response was defined as HBeAg seroconversion and hepatitis B virus (HBV) DNA<105 copies/ml at the end of treatment and after 52 weeks of follow-up. The early HBV DNA data from the first 12 weeks of therapy were fitted by a viral kinetic model.

Results

Cutoff values for prediction of sustained virological response were defined as a rate of infected cell loss δ≥0.005 per day (negative predictive value [NPV] 100% and positive predictive value [PPV] 33.3%) and log values of the area under the mathematically predicted HBV DNA curve between baseline and week 12 of therapy ≤8.9 log10 copies/ml x days (NPV 100% and PPV 50%). By the latter cutoff, 25/36 (69.4%) patients without sustained virological response could be identified after 12 weeks of therapy.

Conclusions

In the present study, mathematical modelling of viral dynamics allowed prediction of sustained virological response after 12 weeks of therapy. Virodynamic predictors for sustained virological response should be further validated. The area under the mathematically predicted HBV DNA curve seems a promising candidate for potential cutoff values as it summarizes the influence of baseline HBV DNA and treatment effects.

Dynamics of lamivudine-resistant hepatitis B virus during adefovir monotherapy versus lamivudine plus adefovir combination therapy

Adefovir dipivoxil has been used alone or together with lamivudine to suppress lamivudine-resistant hepatitis B virus (HBV). However, the dynamics of HBV populations under different selection pressures and their impact on treatment outcome are poorly understood. Pyrosequencing was applied to quantify longitudinally the evolution of wild type and lamivudine/adefovir-resistant HBV. Eight patients, with lamivudine-resistant HBV, were randomized to receive adefovir monotherapy or adefovir/lamivudine combination therapy for a median of 79 and 71 weeks, respectively. Pyrosequencing proved highly sensitive with a lower limit of quantitation of minor HBV populations of 2% irrespective of viraemia levels. Adefovir/lamivudine treatment resulted in greater viraemia reduction than adefovir monotherapy. During combination therapy, lamivudine-resistant HBV populations (codons 180 and 204) remained dominant (>90%) and no adefovir-resistance developed. During adefovir monotherapy, reversion to wild-type HBV was detected in two patients with one patient accumulating rapidly adefovir-resistant HBV along with increased viraemia. In conclusion, the dynamics of drug-resistant HBV strains vary under different selection pressures which have a significant impact on the success of rescue therapy, as well as for the selection of new mutations. The use of techniques such as Pyrosequencing provides an evidence-based approach for successful management of drug-resistant HBV.

Adefovir dipivoxil monotherapy and combination therapy with lamivudine for the treatment of chronic hepatitis B in an Asian population

AIM

To determine differences in Chinese patients treated with adefovir (ADV) monotherapy or ADV in combination with lamivudine (3TC) after development of resistance to 3TC, with respect to biochemical improvement, HBV DNA suppression and development of subsequent ADV resistance.

METHODS

All hepatitis B patients with 3TC resistance treated with ADV for 3 months or more at our centre were included, and monitored 3-6 monthly for biochemical and virological response, and development of ADV resistance.

RESULTS

A total of 56 patients were included, 50% switched to ADV monotherapy and 50% received combination 3TC/ADV therapy. Median follow-up was 15.5 months. Normalization of alanine aminotransferase (ALT) occurred in 25 (89%) patients in the ADV group compared with 24 (86%) in the 3TC/ADV group (P = 0.686). Virological response (VR) was achieved in seven (35%) patients in the ADV group at 12 months compared with five (28%) in the 3TC/ADV group (P = 0.637). By 24 months, seven (64%) patients in the ADV group achieved VR compared with two (40%) in the 3TC/ADV group (P = 0.377). Cumulative probability of developing genotypic ADV resistance in the ADV group at 24 months was 18% compared with 7% in the 3TC/ADV group (P = 0.94).

CONCLUSION

There was no obvious improvement in ALT normalization and virological suppression or reduction in the development of ADV-resistant mutations with 3TC/ADV therapy compared with ADV monotherapy. Further studies with longer follow-ups are required to determine whether combination 3TC/ADV therapy will reduce the emergence of ADV resistance compared with ADV monotherapy.