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Updated: Oct 2, 2025
Detection of Low Copy Number Integrated Viral DNA Formed by In Vitro Hepatitis B Infection
Published on: November 7, 2018
Identification and Characterization of Besifovir-Resistant Hepatitis B Virus Isolated from a Chronic Hepatitis B
Jong Chul Kim1, Hye Young Lee2, Ah Ram Lee1
1Department of Precision Medicine, School of Medicine, Sungkyunkwan University, Suwon 16419, Korea.
Insights
Resistance to Besifovir dipivoxil maleate (BSV), a new Hepatitis B treatment, has emerged. Specific mutations in the HBV reverse transcriptase, rtL180M and rtM204V, confer this resistance, impacting chronic hepatitis B management.
Area of Science:
- Hepatology
- Virology
- Pharmacology
Background:
- Hepatitis B virus (HBV) infection affects 300 million globally, causing severe liver disease.
- Approved treatments include nucleos(t)ide analogs (NAs) and interferon alpha.
- Besifovir dipivoxil maleate (BSV) is a novel oral NA for HBV, with no prior reported resistance.
Purpose of the Study:
- To investigate viral breakthrough in a chronic hepatitis B (CHB) patient treated with BSV.
- To identify mutations in the HBV reverse transcriptase (RT) domain responsible for BSV resistance.
Main Methods:
- Cloning HBV DNA from patient serum into a replication-competent HBV construct.
- Analyzing the RT domain sequence for mutations.
- Performing in vitro drug susceptibility assays on patient-derived and artificial mutant clones.
Main Results:
- A CHB patient exhibited viral breakthrough after long-term BSV treatment.
- Ten mutations were identified in the HBV RT domain of the breakthrough virus.
- In vitro assays revealed that mutations rtL180M and rtM204V confer resistance to BSV.
Conclusions:
- The study identified the first reported resistance to BSV in a CHB patient.
- Known lamivudine-resistant mutations (rtL180M, rtM204V) are responsible for BSV resistance.
- These findings are crucial for monitoring BSV treatment efficacy and managing HBV resistance.
Abstract:
Hepatitis B virus (HBV) is known to cause severe liver diseases such as acute or chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Chronic hepatitis B (CHB) infection is a major health problem with nearly 300 million individuals infected worldwide. Currently, nucleos(t)ide analogs (NAs) and interferon alpha are clinically approved treatments for HBV infection. NAs are potent antiviral agents that bind to HBV polymerase and block viral reverse transcription and replication. Besifovir dipivoxil maleate (BSV) is a newly developed NA against HBV in the form of acyclic nucleotide phosphonate that is available for oral administration similar to adefovir and tenofovir. Until now, resistance to BSV treatment has not been reported. In this study, we found a CHB patient who showed viral breakthrough after long-term treatment with BSV. The isolated HBV DNA from patient's serum were cloned into the replication-competent HBV 1.2 mer and the sequence of reverse transcriptase (RT) domain of HBV polymerase were analyzed. We also examined the drug susceptibility of generated clones in vitro. Several mutations were identified in HBV RT domain. A particular mutant harboring ten RT mutations showed resistance to BSV treatment in vitro. The ten mutations include rtV23I (I), rtH55R (R), rtY124H (H), rtD134E (E), rtN139K (K), rtL180M (M), rtM204V (V), rtQ267L (L), rtL269I (I) and rtL336M (M). To further identify the responsible mutations for BSV resistance, we performed in vitro drug susceptibility assay on several artificial clones. As a result, our study revealed that rtL180M (M) and rtM204V (V) mutations, already known as lamivudine-resistant mutations, confer resistance to BSV in the CHB patient.
