Tenofovir is a more suitable treatment than entecavir for chronic hepatitis B patients carrying naturally occurring rtM204I mutations

Global prevalence and molecular characteristics of three clades within hepatitis B virus subgenotype C2: Predominance of the C2(3) clade in South Korea

Hepatitis B Virus (HBV) genotypes reflect geographic, ethical or clinical traits and are currently divided into 10 genotypes (A–J). Of these, genotype C is mainly distributed in Asia, is the largest group and comprises more than seven subgenotypes (C1–C7). Subgenotype C2 is divided into three phylogenetically distinct clades, C2(1), C2(2), and C2(3), and is responsible for most genotype C infections in three East Asian nations, including China, Japan, and South Korea, which are major HBV endemic areas. However, despite the significance of subgenotype C2 with regard to clinical or epidemiologic aspects, its global distribution and molecular characteristics remain largely unknown. Here, we analyze the global prevalence and molecular characteristics between 3 clades within subgenotype C2 using 1,315 full genome sequences of HBV genotype C retrieved from public databases. Our data show that almost all HBV strains from South Korean patients infected with genotype C belong to clade C2(3) within subgenotype C2 [96.3%] but that HBV strains from Chinese or Japanese patients belong to diverse subgenotypes or clades within genotype C, suggesting clonal expansion of a specific HBV type, C2(3), among the Korean population. Our genome sequence analysis indicated a total of 21 signature sequences specific to the respective clades C2(1), C2(2), and C2(3). Of note, two types of four nonsynonymous C2(3) signature sequences, sV184A in HBsAg and xT36P in the X region, were detected in 78.9 and 82.9% of HBV C2(3) strains, respectively. In particular, HBV strains C2(3) versus C2(1) and C2(2) show a higher frequency of reverse transcriptase mutations related to nucleot(s)ide analog (NA) resistance, including rtM204I and rtL180M, suggesting an increased possibility of C2(3) infection in those with NA treatment failure. In conclusion, our data show that HBV subgenotype C2(3) is extremely prevalent in Korean patients with chronic HBV infection, which is distinct from two other East Asian nations, China and Japan, where diverse subgenotypes or clades within genotype C coexist. This epidemiologic trait might affect distinct virological and clinical traits in chronic HBV patients in Korea, where exclusively C2(3) infection is predominant.

Tenofovir is Superior to Entecavir in Patients with Treatment-naïve Hepatitis B e-Antigen-Positive Chronic Hepatitis B

BACKGROUND AND AIM

Chronic Hepatitis B (CHB) is a global health problem affecting around 400 million of people worldwide. Two available first-line antiviral drugs are tenofovir disoproxil fumarate (TDF) and Entecavir (ETV). Till date,there are few published reports from India comparing efficacy of TDF and ETV in CHB cases. Therefore, this present study was carried out with an aim to compare the efficacy of ETV and TDF in patients with nucleos(t)ide naïve CHB.

MATERIALS AND METHODS

This retrospective cohort study was carried out in 192 treatment naïve CHB cases, who completed 24 months of treatment with either TDF or ETV between March 2015 and August 2017. The primary end point of the study was undetectable hepatitis B virus DNA after 24 months of therapy.

RESULTS

Of total 192 patients with CHB, 38 hepatitis B e-antigen (HBeAg)-positive and 53 HBeAg-negative patients were treated with tenofovir, whereas 40 HBeAg-positive and 61 HBeAg-negative patients were treated with ETV. Pretreatment characteristics at baseline were not statistically different between the TDF and ETV groups. Patients treated with TDF achieved significantly higher complete viral suppression as compared with ETV-treated patients (Log rank: 7.04, P = 0.008) in HBeAg-positive CHB during the 24 months follow-up time; whereas no significant difference in viral suppression rate could be noticed in HBeAg-negative patients (Log rank: 0.98, P = 0.38). Both univariate and multivariate analysis by cox proportional hazard model confirmed that tenofovir had significant rate of complete viral suppression in comparison with ETV in HBeAg-positive patients (P < 0.05); whereas complete viral suppression rates were similar in HBeAg-negative patients.

CONCLUSION

In our study, tenofovir had more effective antiviral suppressive effect compared with ETV in HBeAg-positive, nucleos(t)ide-naïve CHB cases.