Oral antiviral agents have been developed in the last two decades for the treatment of chronic hepatitis B (CHB). However, antiviral resistance remains an important challenge for long-term CHB therapy. All of the clinically available oral antiviral agents are nucleoside or nucleotide analogues that target the activity of viral reverse transcriptase (RT), and all are reported to have resistant mutations. Since the hepatitis B virus (HBV) RT, like other viral polymerases, lacks proofreading activity, the emergence of drug-resistance occurs readily under selective pressure from the administration of antiviral agents. The molecular diagnosis of drug-resistant HBV is based on sequence variations, and current diagnostic methods include sequencing, restriction fragment polymorphism analysis, and hybridization. Here, we will discuss the currently available molecular diagnosis tools, in vitro phenotypic assays for validation of drug-resistant HBV, and treatment options for drug-resistant HBV.

Choi YJ, et al. Clin Mol Hepatol. 2014 Jun;20(2):185-191. http://dx.doi.org/10.3350/cmh.2014.20.2.185

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT• Triple therapy using a proton pump inhibitor with two antibiotics is the standard treatment for H. pylori infection. However, the increasing prevalence of antibiotic resistance has eroded the high success rates initially reported for the standard triple therapy.WHAT THIS STUDY ADDS• Compared with standard triple therapy, amoxicillin/lansoprazole dual therapy, given three times daily for H. pylori had a similar eradication rate with fewer side effects.AIM: We compared three times daily dual therapy with standard triple therapy for effectiveness and safety in H. pylori infection.METHODS: Two hundred and four H. pylori positive patients with peptic ulcer were randomly assigned to one of two regimens: (i) triple therapy with amoxicillin, clarithromycin and lansoprazole twice daily for 2 weeks or (ii) dual therapy with amoxicillin and lansoprazole three times daily for 2 weeks. The success of eradication was evaluated 4 to 5 weeks after completing treatment.RESULTS: The eradication rate was 82.8% in the triple therapy group and 78.4% in the dual therapy group by per protocol analysis. This difference was not significant (P= 0.573). Adverse events were more frequent in the triple therapy group than in the dual therapy group (P= 0.002).CONCLUSIONS: Because dual therapy had fewer side effects than triple therapy and a similar eradication rate, dual therapy may provide an acceptable alternative first line therapy for H. pylori eradication in Korea.