A review of the one-year incidence of resistance to lamivudine in the treatment of chronic hepatitis B : Lamivudine resistance

High Frequency of Antiviral Resistance Mutations in HBV Genotypes A2 and H: Multidrug Resistance Strains in Mexico

Background and Aims

Lamivudine (3TC), telbivudine (LdT), entecavir (ETV), adefovir (ADF), and tenofovir (TFV) are drugs used to treat hepatitis B virus (HBV) infection, but specific mutations allow some viruses to become resistant to antiviral drugs or to acquire immune escape capacities. These mutations have not been thoroughly investigated in Mexico. This study aimed to estimate the prevalence of HBV antiviral resistance and escape mutations.

Methods

This cross-sectional study analyzed 158 samples. HBV DNA was extracted, amplified, and sequenced in serum samples using the spin column method, PCR assay, and Sanger's sequencing, respectively. HBV genotypes were determined, and HBV mutations were tested using the Geno2pheno tool.

Results

Overall, 68.4% (108/158) of HBV patients were infected with genotype H, followed by G (11.4%, 18/158), A2 (10.8%, 17/158), F1b (6.9.0%, 11/158), D (1.9%, 3/158), and E (0.6%, 1/158), and 5.1% (8/158) had evidence of recombination. The prevalence of resistance mutations was 8.2% (13/158) and the most common combined mutation was rt180M+rt204V. Notably, we found the combinations rt180M+rt204V+rt173L (n=2) and rt180M+rt204V+rt202G (n=1) that confer multidrug resistance to 3TC, LdT, and ETV. Resistance mutations were found in genotypes A2 (11.8%, 2/17), and H (10.2%, 11/108), and escape mutations were detected in HBV genotypes A2 (11.8%, 2/17), H (10.2%, 11/108), F1b (9.1%, 1/11) and G (5.6%, 1/18).

Conclusions

The highest prevalence of antiviral resistance mutations or escape mutations was detected in HBV genotypes A2 and H. The earliest cases of HBV multidrug resistance were detected in Mexico.

[Prevalence and molecular genetic characteristics of parenteral hepatitis B, C and D viruses in HIV positive persons in the Novosibirsk region]

INTRODUCTION

Parenteral viral hepatitis (B, C, D) and HIV share modes of transmission and risk groups, in which the probability of infection with two or more of these viruses simultaneously is increased. Mutual worsening of the course of viral infections is important issue that occurs when HIV positive patients are coinfected with parenteral viral hepatitis. The aim of the study was to determine the prevalence of HCV, HBV and HDV in HIV positive patients in the Novosibirsk region and to give molecular genetic characteristics of their isolates.

MATERIALS AND METHODS

Total 185 blood samples were tested for the presence of total antibodies to HCV, HCV RNA, HBV DNA and HDV RNA. The identified isolates were genotyped by amplification of the NS5B gene fragment for HCV, the polymerase gene for HBV and whole genome for HDV.

RESULTS

The total antibodies to HCV were detected in 51.9% (95% CI: 44.758.9), HCV RNA was detected in 32.9% (95% CI: 26.639.5) of 185 studied samples. The distribution of HCV RNA positive cases completely repeated the distribution of HCV serological markers in different sex and age groups. The number of HCV infected among HIV positive patients increases with age. HCV subgenotypes distribution was as follows: 1b (52.5%), 3а (34.5%), 1а (11.5%), 2а (1.5%). 84.3% of detected HCV 1b isolates had C316N mutation associated with resistance to sofosbuvir and dasabuvir. The prevalence of HBV DNA in the studied samples was 15.2% (95% CI: 10.721.0). M204I mutation associated with resistance to lamivudine and telbivudine was identified in one HBV isolate. Two HDV isolates that belonged to genotype 1 were detected in HIV/HBV coinfected patients.

CONCLUSION

The data obtained confirm the higher prevalence of infection with parenteral viral hepatitis among people living with HIV in the Novosibirsk region compared to the general population of that region. The genetic diversity of these viruses among HIV infected individuals is similar to that observed in the general population.

Compensatory variances of drug-induced hepatitis B virus YMDD mutations

Although the drug-induced mutations of HBV have been ever documented, the evolutionary mechanism is still obscure. To deeply reveal molecular characters of HBV evolution under the special condition, here we made a comprehensive investigation of the molecular variation of the 3432 wild-type sequences and 439 YMDD variants from HBV genotype A, B, C and D, and evaluated the co-variant patterns and the frequency distribution in the different YMDD mutation types and genotypes, by using the naïve Bayes classification algorithm and the complete induction method based on the comparative sequence analysis. The data showed different compensatory changes followed by the rtM204I/V. Although occurrence of the YMDD mutation itself was not related to the HBV genotypes, the subsequence co-variant patterns were related to the YMDD variant types and HBV genotypes. From the hierarchy view, we clarified that historical mutations, drug-induced mutation and compensatory variances, and displayed an inter-conditioned relationship of amino acid variances during multiple evolutionary processes. This study extends the understanding of the polymorphism and fitness of viral protein.

Randomized, three-arm study to optimize lamivudine efficacy in hepatitis B e antigen-positive chronic hepatitis B patients

BACKGROUND AND AIM

Data about the efficacy of de novo combination therapies, or optimization strategy by adding the other drug based on the virological response at week 24 of low genetic barrier antiviral agents is still limited. This study aimed to compare the efficacy at week 104 of lamivudine monotherapy (MONO), lamivudine plus adefovir dipivoxil (ADV) combination therapy (COMBO), and lamivudine optimization strategy (OPTIMIZE).

METHODS

Adult patients without antiviral therapy within 6 months before screening with hepatitis B virus (HBV)-DNA ≥ 10(5) copies/mL, alanine aminotransferase 1.3-10 times upper limit of normal and compensated hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) were randomized into three groups with 1:1:1 ratio. Patients in OPTIMIZE group started with lamivudine 100 mg q.d., and ADV 10 mg q.d. was added to suboptimal responders (HBV-DNA > 1000 copies/mL at week 24) from week 30 to week 104, whereas patients with early virological response (HBV-DNA ≤ 1000 copies/mL at week 24) continued MONO until week 104. For all the patients receiving MONO, ADV would be added if virological breakthrough was confirmed.

RESULTS

At week 104, more patients in COMBO and OPTIMIZE groups achieved HBV-DNA < 300 copies/mL (53.3% [64/120] and 48.3% [58/120]), with less lamivudine resistance (0.8% and 6.7%) compared with MONO group (HBV-DNA < 300 copies/mL 34.8% [41/118], lamivudine resistance 58.5%). Patients under MONO with early virological response showed superior efficacy at week 104 (HBV-DNA < 300 copies/mL 73.1% [38/52], HBeAg seroconversion 40.4% [21/52]). All regimens were well tolerated.

CONCLUSION

Combination therapy of lamivudine plus ADV exhibited effective viral suppression and relatively low resistance in HBeAg-positive CHB patients. In lamivudine-treated patients with suboptimal virological response at week 24, promptly adding on ADV is necessary to prevent resistance development.

Giving rituximab in patients with occult or resolved hepatitis B virus infection: are the current guidelines good enough?

INTRODUCTION

Hepatitis B virus (HBV) reactivation after 'resolved' infection can occur in the setting of immunosuppression, including iatrogenically induced by anti-CD20 antibodies. The presence of antibodies against the HBV core antigen (anti-HBc) is a marker of risk for this phenomenon. The risk of this occurring in patients with circulating HBV surface antigen (HBsAg) is well characterized, but is less well characterized in patients who are HBsAg negative.

AREAS COVERED

This article reviews the literature regarding HBV reactivation in the context of rituximab therapy. We have limited our review to HBsAg-negative patients, and clinical outcomes following HBV reactivation.

EXPERT OPINION

We have recommended prophylactic anti-viral therapy for all HBsAg-negative/anti-HBc-positive patients undergoing rituximab therapy in combination with other immunosuppressive therapy.

A drug safety evaluation of rituximab and risk of hepatitis B

INTRODUCTION

Rituximab is a widely prescribed anti-CD20 mAb for the treatment of CD20(+) B-cell non-Hodgkin Lymphoma and many other immune mediated conditions. There is a well-described association between rituximab containing chemo-immunotherapy treatment and reactivation of the hepatitis B virus (HBV). This review summarizes the current literature surrounding rituximab-associated HBV reactivation.

AREAS COVERED

Herein, we review the literature detailing the risk of HBV reactivation in inactive carriers and those with resolved hepatitis. The clinical presentation and management of HBV reactivation are also discussed along with a summary of clinical trials evaluating antiviral prophylaxis. Finally, clinical recommendations are detailed. Data from clinical trials, observational studies, reviews, and meta-analyses available in the Medline database were included in this narrative review.

EXPERT OPINION

Screening should be performed in all patients prior to the administration of any type of anti-CD20 mAb therapy. Among those with positive screening serology, testing for hepatitis B e antigen or viral load by polymerase chain reaction is appropriate. In those patients with detectable HBV DNA, the decision regarding the use of antiviral prophylaxis or observation should be individualized.

Hepatitis B virus management to prevent reactivation after chemotherapy: a review

PURPOSE

Reactivation of hepatitis B virus (HBV) infection after chemotherapy can lead to liver failure and death. Conflicting recommendations regarding HBV screening in cancer patients awaiting chemotherapy mean that some patients at risk for HBV reactivation are not being identified and treated with prophylactic antiviral therapy.

METHODS

We performed a narrative review of the existing evidence regarding screening for and management of HBV infection among patients with cancer using Ovid Medline, PubMed, and the Cochrane Library.

RESULTS

Our review showed inconsistencies in the definition and management strategies for HBV reactivation. The timeframe of reactivation is variable, and its molecular mechanisms are not clear. There are five effective antiviral agents that can be used as prophylaxis to prevent reactivation of HBV infection in cancer patients; however, the optimal drug and duration of therapy are unknown. Reactivation is more commonly reported in patients with hematologic malignancies receiving rituximab treatment, but reactivation can occur after other chemotherapies and in patients with solid tumors. Screening with all three screening tests-HBsAg, anti-HBc, and anti-HBs-allows the most thorough interpretation of a patient's serologic profile and assessment of reactivation risk; however, decision-making and cost-effectiveness studies are needed to determine optimal screening strategies.

CONCLUSIONS

Prevention of reactivation of HBV infection depends on identification of patients at risk and initiation of antiviral prophylaxis, but data to guide screening and treatment strategies are lacking. Additional research is necessary to accurately define and predict reactivation, identify best antiviral treatment strategies, and identify cost-effective HBV screening strategies.

Question of ALT flare during switch to adefovir from lamivudine: A single center open-label, randomized, safety study (June 17, 2005 to February 5, 2009)

Earlier clinical studies have reported an ALT flare greater than 10 times the upper limit of normal in some patients with chronic hepatitis B when their lamivudine (LAM) treatment was switched to adefovir (ADV) therapy. The current study compared the safety of switching directly to ADV versus overlapping LAM and ADV for 3 months followed by ADV monotherapy. Patients with chronic hepatitis B receiving LAM therapy for > or = 6 months were eligible for the study regardless of the presence of LAM resistance, HBeAg status or serum ALT levels. Eighteen patients (13 males) were randomized to direct switch to ADV and 17 patients (10 males) to overlap. HBV-DNA, ALT, albumin, and total bilirubin were assayed at baseline, 3, 6, 9, and 12 months. Study drugs were discontinued at the end of 12 months with the follow up at 3 and 6 months. The decision to continue antiviral therapy was made at the discretion of the investigator. Baseline ALT levels were similar between the direct switch and overlap group: median ALT (U/L) was 44.0 (16-266) and 33.0 (19-367) for direct switch for overlap group, respectively (P = 0.42). No ALT flare was noted at 3 months in either group: median ALT decreased from 44.0 to 34.5 U/L in the direct switch group, and from 33.0 to 23.0 in the overlap group. Furthermore, no patient in either group exhibited ALT flare throughout the 12 months. This study did not show an ALT flare during switch to ADV at 3 months or at any time later.

Safety of tumor necrosis factor alpha blockers in hepatitis B virus occult carriers (hepatitis B surface antigen negative/anti-hepatitis B core antigen positive) with rheumatic diseases

OBJECTIVE

To assess the safety of anti-tumor necrosis factor alpha (anti-TNFalpha) therapy on the course of hepatitis B virus (HBV) infection in carriers of antibodies to hepatitis B core antigen (anti-HBc) affected by chronic inflammatory arthropathies.

METHODS

From January 2001 to December 2008, HBV markers were determined before the first administration of anti-TNFalpha agents in all 732 patients affected by inflammatory arthropathies treated with anti-TNFalpha at 2 outpatient rheumatologic clinics in Northern Italy. Anti-HBc-positive patients were prospectively evaluated and HBV markers and HBV DNA were assessed every 6 months, in case of aminotransferase elevation, and at the end of the study.

RESULTS

At the time of recruitment, 72 patients were anti-HBc carriers, 5 of whom were positive for hepatitis B surface antigen (HBsAg) and not included in the study. The ratio of men:women was 26:41 and the mean +/- SD followup was 42.52 +/- 21.33 months. Of the patients, 25 were treated with infliximab, 23 with etanercept, and 19 with adalimumab. Fifty-one patients were treated also with methotrexate, 52 with nonsteroidal antiinflammatory drugs, and 43 with prednisone (3 with a dosage >7.5 mg/day). All anti-HBc patients were HBV DNA negative at the first observation. During followup, no patient presented HBV reactivation with viral load increase and no patient became HBsAg positive.

CONCLUSION

Anti-HBc positivity in HBsAg-negative patients is a sign of previous HBV infection and does not indicate chronic hepatitis. In these patients, anti-TNFalpha therapy appears to be quite safe, as no HBV reactivation was found in our study. Nevertheless, careful monitoring is necessary.