Besifovir therapy improves hepatic histology and reduces covalently closed circular DNA in chronic hepatitis B patients

Noninferiority Outcomes of Besifovir Compared to Tenofovir Alafenamide in Treatment-Naïve Patients with Chronic Hepatitis B

Background/Aims

: Besifovir dipivoxil maleate (BSV) and tenofovir alafenamide fumarate (TAF) have been recently approved in Korea as the initial antiviral agents for chronic hepatitis B (CHB). However, the real-world outcome data for these drugs remain limited. Therefore, we conducted a noninferiority analysis using real-world data to compare the clinical outcomes of the two nucleotide analogs in treatment-naïve patients with CHB.

Methods

: We retrospectively investigated a cohort of patients with CHB who received BSV or TAF as first-line antiviral agents. The endpoints were virological response (VR) and liver-related clinical outcomes.

Results

: A total of 537 patients, consisting of 202 and 335 patients administered BSV and TAF, respectively, were followed up for 42 months. No significant difference was observed between the VRs of the patients from the two groups. The rates of biochemical response, virologic breakthrough, and incidence rates of hepatocellular carcinoma did not differ between the groups. However, the hepatitis B e antigen seroclearance rate was higher and the renal function declined less in the BSV group. Multivariable analysis indicated older age, alcohol abuse, cirrhosis and ascites, and lower serum HBV DNA level to be independently associated with increased hepatocellular carcinoma risk. The 1:1 propensity score-matched analysis with 400 patients showed VR rates of 85.0% and 88.7% in the BSV and TAF group patients, respectively, at 2 years. The absolute value of the 95% confidence interval for the difference (-0.04 to 0.12) satisfied the a priori limit of a noninferiority of 0.15.

Conclusions

: BSV is noninferior to TAF in terms of VR, and their clinical outcomes are comparable to CHB.

Reduced Risk of Hepatocellular Carcinoma in Patients with Chronic Hepatitis B Receiving Long-Term Besifovir Therapy

No information is available regarding the influence of besifovir (BSV), a new nucleotide analogue, on the occurrence of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). This study evaluated the reduced risk of HCC in patients undergoing BSV treatment. A total of 188 patients with CHB were treated with BSV for up to 8 years. We prospectively assessed the incidence of HCC compared with the risk from prediction models. During the follow-up, 5 patients developed HCC: 1 of 139 patients with non-cirrhotic CHB, and 4 of 49 patients with liver cirrhosis. We compared the HCC incidence in non-cirrhotic and cirrhotic patients with the predicted number derived from the REACH-B (risk estimation for HCC in CHB) model and GAG-HCC (guide with age, gender, HBV DNA, core promotor mutation, and cirrhosis) model, respectively. The standardized incidence ratio (SIR) was 0.128 (p = 0.039) at 7 years in non-cirrhotic CHB patients, and the SIR was 0.371 (p = 0.047) at 7.5 years in cirrhotic patients, suggesting a significantly decreased HCC incidence in both groups. HCC prediction was available for BSV-treated patients using existing models. In conclusion, BSV decreased the risk of HCC in patients with CHB, and prediction models were applicable. Clinical trial registry website and trial number: ClinicalTrials.gov no: NCT01937806.

Cholecystectomy reduces the risk of myocardial and cerebral infarction in patients with gallstone-related infection

We compared the risk of myocardial infarction (MI) or cerebral infarction (CI) in patients with or without-gallstone-related infection (GSI) and change in the risk following cholecystectomy. GSI (n = 84,467) and non-GSI (n = 406,800) patients with age- and sex-matched controls (n = 4,912,670) were identified from Korean population based data. The adjusted hazard ratios (aHRs) of MI or CI were analyzed in both groups treated with or without cholecystectomy. Subgroup analysis was performed for both sexes and different ages. The risk of MI or CI was higher in the GSI group than in the non-GSI group (aHR for MI; 1.32 vs. 1.07, aHR for CI; 1.24 vs. 1.06, respectively). The risk reduction rate of MI following cholecystectomy was 11.4% in the GSI group, whereas it was 0% in the non-GSI group. The risk of CI after cholecystectomy was more reduced in the GSI group than in the non-GSI group (16.1% and 4.7%, respectively). The original risk of MI or CI in patients with gallstones and risk reduction rates following cholecystectomy were higher in females and younger patients than in males and older patients. Increased risk of MI or CI and greater risk reduction following cholecystectomy were seen in patients with GSI.

Identification and Characterization of Besifovir-Resistant Hepatitis B Virus Isolated from a Chronic Hepatitis B Patient

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.