HBV Carrying Drug-Resistance Mutations in Chronically Infected Treatment-Naive Patients

Abstract

HBV strains harbouring resistance mutations can comprise the major population of HBV quasispecies in treatment-naive patients. In Brazil, there is a very low frequency of untreated patients who are infected with these strains. These findings suggest that the spread and natural selection of drug-resistant HBV is an uncommon event and/or most of these strains remain unstable in the absence of NA selective pressure.

Hepatitis B Virus Carrying Drug-resistance Compensatory Mutations in Chronically Infected Treatment-naive Patients

“…It has been reported that rtQ215H/Q/P/S compensatory mutations are frequently observed in CHB patients who receive both NA-naive and LAM and/or ADV treatments (11,12). In our study, there were compensatory mutations in 19 patients and 4 of them had rtQ149K compensatory mutation which was associated with LAM and ADV treatment.…”

“…NA resistance mutations can occur in non-treated patients because of the viral and patient factors. The reasons for the variance of resistance in non-treated patients are: 1) these mutations can naturally occur during the replication (10 -5 -10 -4 substitution/base/ cycle), 2) the patient can be infected by a mutant virus from another patient who was previously treated, and 3) the patient can be directly and unconsciously exposed to equivalent components with anti-HBV activity (12,16). Thus, resistance mutations can be observed in non-treated patients.…”

“…NA inhibits the activity of HBV polymerase and suppresses its replication by binding it competitively. However, the drug resistance is a common problem in long-term treatments (12). Furthermore, recent studies showed that there is an antiviral resistance even in HBV isolated from nontreated patients (13).…”

Clinical, demographic, and epidemiologic characteristics of hepatitis B virus-infected patients at a tertiary public hospital in Presidente Prudente, State of São Paulo, Brazil

“…However, an important factor in this study was the large number of patients with high alcohol consumption that might have affected the serum ALT results. Few studies have investigated antiviral therapy in Brazil and most of them have highlighted gene mutations and HBV genotypes (11) (20) (21) . In line with our results, tenofovir was the most prescribed drug for individuals with chronic HBV in the neighboring state of Parana (21) ; however, lamivudine monotherapy was the chosen treatment in 66.7% of patients in a cross-sectional study of patients chronically infected with HIV in different Brazilian sites (11) .…”

“…Few studies have investigated antiviral therapy in Brazil and most of them have highlighted gene mutations and HBV genotypes (11) (20) (21) . In line with our results, tenofovir was the most prescribed drug for individuals with chronic HBV in the neighboring state of Parana (21) ; however, lamivudine monotherapy was the chosen treatment in 66.7% of patients in a cross-sectional study of patients chronically infected with HIV in different Brazilian sites (11) . In an American community-based cohort, antiviral therapy and viral suppression were the most effective ways to reduce the incidence of HBV-induced HCC; this fi nding was confi rmed in Asian and Europeans studies (22) .…”