Identification of a quadruple mutation that confers tenofovir resistance in chronic hepatitis B patients.
J Hepatol
; 70(6): 1093-1102, 2019 06.
Article
in En
| MEDLINE
| ID: mdl-30794889
ABSTRACT
BACKGROUND & AIMS:
Tenofovir disoproxil fumarate (TDF) is one the most potent nucleot(s)ide analogues for treating chronic hepatitis B virus (HBV) infection. Phenotypic resistance caused by genotypic resistance to TDF has not been reported. This study aimed to characterize HBV mutations that confer tenofovir resistance.METHODS:
Two patients with viral breakthrough during treatment with TDF-containing regimens were prospectively enrolled. The gene encoding HBV reverse transcriptase was sequenced. Eleven HBV clones harboring a series of mutations in the reverse transcriptase gene were constructed by site-directed mutagenesis. Drug susceptibility of each clone was determined by Southern blot analysis and real-time PCR. The relative frequency of mutants was evaluated by ultra-deep sequencing and clonal analysis.RESULTS:
Five mutations (rtS106C [C], rtH126Y [Y], rtD134E [E], rtM204I/V, and rtL269I [I]) were commonly found in viral isolates from 2 patients. The novel mutations C, Y, and E were associated with drug resistance. In assays for drug susceptibility, the IC50 value for wild-type HBV was 3.8⯱â¯0.6⯵M, whereas the IC50 values for CYE and CYEI mutants were 14.1⯱â¯1.8 and 58.1⯱â¯0.9⯵M, respectively. The IC90 value for wild-type HBV was 30⯱â¯0.5⯵M, whereas the IC90 values for CYE and CYEI mutants were 185⯱â¯0.5 and 790⯱â¯0.2⯵M, respectively. Both tenofovir-resistant mutants and wild-type HBV had similar susceptibility to the capsid assembly modulator NVR 3-778 (IC50â¯<0.4⯵M vs. IC50â¯=â¯0.4⯵M, respectively).CONCLUSIONS:
Our study reveals that the quadruple (CYEI) mutation increases the amount of tenofovir required to inhibit HBV by 15.3-fold in IC50 and 26.3-fold in IC90. These results demonstrate that tenofovir-resistant HBV mutants can emerge, although the genetic barrier is high. LAYSUMMARY:
Tenofovir is the most potent nucleotide analogue for the treatment of chronic hepatitis B virus infection and there has been no hepatitis B virus mutation that confers >10-fold resistance to tenofovir up to 8â¯years. Herein, we identified, for the first time, a quadruple mutation that conferred 15.3-fold (IC50) and 26.3-fold (IC90) resistance to tenofovir in 2 patients who experienced viral breakthrough during tenofovir treatment.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Antiviral Agents
/
Hepatitis B virus
/
RNA-Directed DNA Polymerase
/
Reverse Transcriptase Inhibitors
/
Hepatitis B, Chronic
/
Tenofovir
/
Mutation
Type of study:
Diagnostic_studies
Limits:
Aged
/
Humans
/
Male
Language:
En
Journal:
J Hepatol
Journal subject:
GASTROENTEROLOGIA
Year:
2019
Document type:
Article