Pre-existing mutations related to tenofovir in chronic hepatitis B patients with long-term nucleos(t)ide analogue drugs treatment by ultra-deep pyrosequencing.
OBJECTIVE
The dynamics of resistance-associated mutations under combination therapy were explored.


METHODS
A total of 46 patients were classified into adefovir (n=14) and entecavir (n=32) groups. In the adefovir (ADV) group, six patients receiving combined therapy were DNA-positive after more than 3 years of therapy. Ultra-deep pyrosequencing was used to analyze the dynamics of multi-drugs resistance mutations.


RESULTS
At baseline, all 46 treatment-naïve patients harbored rtA181V/T substitutions (1.2%-4.6%) and rtN236T substitutions (1.6%-6.1%). In the ADV group, eight patients with long-term treatment were consecutively HBV DNA-positive for more than 3 years. During treatment, the rtA181T resistance-associated site appeared with increasing frequency in six of eight patients (NOs. 1-6), and two patients (NOs.4 and 8) carrying the rtA181T resistance mutations increasingly showed high levels of rtN236T. One patient (NO. 8) experienced virological breakthrough. Other known pre-existing mutations showed no dynamic fluctuations, including in rtA194T, rtP177G, rtF249A, and rtD263E. In addition to the common substitutions, some previously unknown amino acid substitutions, such as rtD134N, rtL145M/S, rtF151Y/L, rtR153Q, and rtS223A, should be further studied.


CONCLUSIONS
HBV-resistance substitutions conferring to nucleoside analogs are present at baseline. The dynamics of the HBV RT-region quasispecies variation are heterogeneous and complex.
Department of Infectious Disease, Peking University First Hospital, Xicheng District, Beijing 100034, China.
Xiaxia
X
Zhang
Division of Liver Disease, The Fifth Hospital of Shijiazhuang, Hebei Medical University, Shijiazhuang 050023, China.
Minran
M
Li
Department of Infectious Disease, Peking University First Hospital, Xicheng District, Beijing 100034, China.
Hongli
H
Xi
Department of Infectious Disease, Peking University First Hospital, Xicheng District, Beijing 100034, China.
Renwen
R
Zhang
Department of Infectious Disease, Peking University First Hospital, Xicheng District, Beijing 100034, China.
Jianhong
J
Chen
Department of Infectious Disease, Peking University First Hospital, Xicheng District, Beijing 100034, China.
Yu
Y
Zhang
Department of Infectious Disease, Peking University First Hospital, Xicheng District, Beijing 100034, China.
Xiaoyuan
X
Xu
D000225:Adenine / Q000031:analogs & derivatives / Q000627:therapeutic use; D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use*; D004279:DNA, Viral / Q000097:blood; D018432:Drug Resistance, Multiple / Q000235:genetics; D005260:Female; D019694:Hepatitis B, Chronic / Q000188:drug therapy* / Q000235:genetics / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D063065:Organophosphonates / Q000627:therapeutic use; D017422:Sequence Analysis, DNA; D000068698:Tenofovir / Q000627:therapeutic use*
D000998:Antiviral Agents; D004279:DNA, Viral; D063065:Organophosphonates; C053001:adefovir; D000068698:Tenofovir; D000225:Adenine
hepatitis B virus; multi-drugs therapy; resistance; tenofovir; ultra-deep pyrosequencing