Monitoring of genotypic resistance profile in chronic hepatitis B patients receiving nucleos(t)ide analogues in Huzhou, China.

Introduction: Antiviral drug-resistance patterns of hepatitis B virus (HBV) mutants are complex and currently partly understood. The aim of this study was to monitor the genotypic resistance profile in patients with chronic hepatitis B (CHB) receiving nucleos(t)ide analogues (NAs) in Huzhou, eastern China.

Methodology: Serum samples of 139 CHB patients undergoing NA treatment were obtained from Huzhou Central Hospital. The full-length HBV reverse transcriptase regions were amplified and sequenced. The NA resistance mutation positions, including rtL80, rtI169, rtV173, rtL180, rtA181, rtT184, rtA194, rtS202, rtM204, rtI233, rtN236, and rtM250 were analyzed.

Results: Genotypic resistance mutations were detected in 41.72% (58/139) of patients with CHB. Drug resistance mutations were detected at positions rt80, rt173, rt180, rt181, rt194, rt202, rt204, rt236, and rt250, but were not observed at positions rt169, rt184, and rt233. The prevalence of mutations at rtM204 was 54.44% in 90 patients who were treated with lamivudine (LAM) or telbivudine (LDT). RtN236 mutations were detected in 7.14% (2/28) of the patients receiving adefovir (ADV) therapy. Additionally, rtA181 mutations were observed in 4 patients with LAM, ADV, and LDT-based therapy, but not in those patients treated with entecavir (ETV). Among patients who harbored rtM204 combination mutations, rtM204I and rtM204V were significantly associated with rtL80I/V and rtL180M, respectively.

Conclusions: The mutation patterns of NA-resistant HBV are complicated in CHB patients in the current clinical setting. Thus, it is necessary to persistently monitor the resistance mutations of HBV for optimizing antiviral therapy strategy and for preventing an outbreak of clinical resistance.