Background/Aims: Ledipasvir/sofosbuvir (LDV/SOF) shows high efficacy and safety in patients with genotype 1-hepatitis C virus (HCV). We aimed to investigate the efficacy and safety of LDV/SOF in real-world Mongolian patients. Methods: Between 2015 to 2019, 23 (0.5%) and 5,005 patients (99.5%) with genotype 1a and 1b HCV, respectively, were treated with a fixed-dose tablet containing 90 mg ledipasvir and 400 mg sofosbuvir for 12 weeks, and 81 patients (1.6%) with previous experience of interferon (IFN)-based treatment received additional 1,000 mg ribavirin. HCV RNA was measured at 4, 12, and 24 weeks after the first dose to determine rapid virologic response, end of treatment response (ETR), and sustained virologic response at 12 weeks after end of treatment (SVR12). Results: Most patients (n=5,008; 99.6%) achieved ETR and SVR12 without virologic relapse. Patients with genotype 1a showed low rates of ETR and SVR12 in only 16 patients (69.6%). There was no significant difference in SVR12 rate between patients regardless of IFN experience (n=81; 1.6%), cirrhosis (n=1,151; 22.9%), HCV RNA >6×106 IU/mL (n=866; 17.2%), or liver stiffness >9.6 kPa (n=1,721; 34.2%) (100.0%, 99.3%, 99.4%, and 99.4%, respectively). No severe adverse events (AEs) were reported, and there was no dose reduction or interruption due to AE. The most common AEs were headache (n=472; 9.4%), fatigue (n=306; 6.2%), abdominal discomfort (n=295; 5.9%), and skin rash (n=141; 2.8%). Conclusions LDV/SOF showed high efficacy and safety for patients with genotype 1, especially 1b HCV, in Mongolia. The real-world data might be applicable to patients in other Asian-Pacific countries.

Background/Aims: The hepatic steatosis index (HSI) is a noninvasive method to assess the severity of hepatic steatosis. Antiviral therapy (AVT) can impact aspartate aminotransferase and alanine aminotransferase levels, which are the main components of the HSI. Thus, we investigated the accuracy of the HSI in detecting hepatic steatosis in patients with chronic hepatitis B (CHB) receiving AVT, compared with those not receiving AVT and in those with nonalcoholic fatty liver disease (NAFLD). Methods: Patients with CHB or NAFLD who underwent a magnetic resonance imaging proton density fat fraction (MRI-PDFF) evaluation between March 2010 and March 2019 were recruited.Hepatic steatosis was diagnosed when the PDFF exceeded 5%. Area under the receiver operating characteristic curve (AUROC) analysis was used to assess the diagnostic accuracy of the HSI in the detection of hepatic steatosis. Results: The mean age of the study population (189 men and 116 women; 244 with CHB [184 with and 60 without AVT] and 61 with NAFLD) was 55.6 years. The AUROC values for detecting hepatic steatosis were similar between patients with CHB (0.727; p<0.001) and those with NAFLD (0.739; p=0.002). However, when patients with CHB were subdivided into those receiving and not receiving AVT, the AUROC value decreased slightly in patients with CHB receiving AVT compared to those without not receiving AVT (0.707; p=0.001 vs 0.779; p=0.001). Conclusions Despite a slight attenuation, the diagnostic accuracy of the HSI in patients with CHB receiving AVT in detecting hepatic steatosis was still acceptable. Further large-scale studies are required for validation.

Background/Aims: Glecaprevir/pibrentasvir (G/P) is the first pan-genotypic direct-acting antiviral combination therapy approved in Korea. An integrated analysis of five phase II and III trials was conducted to evaluate the efficacy and safety of G/P in Korean patients with chronic hepatitis C virus (HCV) infection. Methods: The study analyzed pooled data on Korean patients with HCV infection enrolled in the ENDURANCE 1 and 2, SURVEYOR II part 4 and VOYAGE I and II trials, which evaluated the efficacy and safety of 8 or 12 weeks of G/P treatment. The patients were either treatment-naïve or had received sofosbuvir or interferon-based treatment. Efficacy was evaluated by assessing the rate of sustained virologic response at 12 weeks posttreatment (SVR12). Safety was evaluated by monitoring adverse events (AEs) and laboratory assessments. Results: The analysis included 265 patients; 179 (67.5%) were HCV treatment-naïve, and most patients were either subgenotype 1B (48.7%) or 2A (44.5%). In the intention-to-treat population, 262 patients (98.9%) achieved SVR12. Three patients did not achieve SVR12: one had virologic failure and two had non-virologic failures. Most AEs were grade 1/2; eight patients (3.0%) expe-rienced at least one grade ≥3 AE. No serious AEs related to G/P treatment were reported, and grade ≥3 hepatic laboratory abnormalities were rare (0.8%). Conclusions G/P therapy was highly efficacious and well tolerated in Korean patients with HCV infection, with most patients achieving SVR12. The safety profile was comparable to that observed in a pooled analysis of a global pan-genotypic population of patients with HCV infection who received G/P.

Background/Aims: Besifovir dipivoxil maleate (BSV), an acyclic nucleotide phosphonate, shows potent antiviral activity against hepatitis B virus. Our previous 48-week trial revealed that BSV has comparable antiviral efficacy to tenofovir disoproxil fumarate (TDF) and better safety profiles in terms of improved renal and bone safety. This extension study evaluated the prolonged efficacy and safety of BSV in treatment-naive chronic hepatitis B patients. Methods: Patients continued to participate in an open-label BSV study after an initial 48-week double-blind comparison of BSV and TDF treatment. The antiviral efficacy and drug safety was evaluated up to 192 weeks in two groups: patients continuing BSV treatment (BSV-BSV) and patients switching from TDF to BSV after 48 weeks (TDF-BSV). Results: Among 197 patients receiving randomized treatments, 170 (86%) entered the open-label phase and 152 (77%) entered the 192-week extension study. Virological response rates over 192 weeks were 92.50% and 93.06% in the BSV-BSV and TDF-BSV groups, respectively (P=0.90). Hepatitis B envelop antigen seroconversion and alanine aminotransferase normalization rates were similar between the groups (P=0.75 and P=0.36, respectively). There were no drug-resistant mutations to BSV. Bone mineral density and renal function were well preserved in the BSV-BSV group, whereas these initially worsened then recovered after switching therapy in the TDF-BSV group. Conclusions BSV maintained potent antiviral efficacy after 192 weeks and showed no evidence of drug resistance. BSV was safe, well tolerated, and effective in patients who switched from TDF to BSV. Trial Registration Number: NCT01937806 (date: 10 Sep 2013).

Background/Aims: The immune-tolerant (IT) phase of chronic hepatitis B (CHB) patients is not generally indicative of antiviral therapy (AVT). We assessed and compared the risk of hepatocellular carcinoma (HCC) during the IT-phase stringently defined by a low fibrosis-4 (FIB-4) index, compared to that in patients undergoing AVT. Methods: Among 125 untreated patients that were hepatitis B e-antigen positive, hepatitis B virus-DNA >20,000 IU/mL, with normal alanine aminotransferase level from 2012 to 2018, those with a FIB-4 index of <1.45 were classified into the IT-group. The cumulative probability of HCC was estimated using Kaplan-Meier analysis. All patients were assessed until HCC development (intention-to-treat [ITT] analysis), whereas those suspected of experiencing CHB phase switch were assessed using the per-protocol (PP) and censored at the time of phase switch. Results: The cumulative probability of HCC at 1-, 3-, and 5-years among the IT-group was zero, compared to AVT-treated patients with FIB-4 indices <1.45 during the same period: 0.2%, 0.6%, and 1.4%, respectively (P=0.264 for ITT and P=0.533 for PP). Among the initially screened 125 untreated patients, those with a FIB-4 index of ≥1.45 had a higher risk of HCC compared to the IT-group (P=0.005). Furthermore, among AVT-treated patients, those with a FIB-4 index of ≥1.45 had a higher risk of HCC compared to their counterpart (P<0.001). Conclusions The risk of HCC was negligible in the IT-group stringently defined by a low FIB-4 index. However, given that a higher HCC risk exists among untreated patients with higher FIB-4, appropriate criteria for AVT should be established.

Background/Aims: We investigated changes in recurrence rates and significant recurrence predictors over time after complete cure of hepatocellular carcinoma (HCC). Methods: A total of 1,491 patients with first-time diagnosis of Barcelona Clinic Liver Cancer stage A HCC, completely cured by treatment between 2007 and 2016, were recruited from two Korean tertiary institutes. Results: The mean age of the population (1,144 men and 347 women) was 58.6 years. Of the total population, 914 patients (61.3%) had liver cirrhosis. Nine-hundred and forty-one (63.1%) and 550 (36.9%) patients were treated with surgical resection and radiofrequency ablation (RFA), respectively. One-year cumulative incidences of HCC recurrence were 14.3%, 9.9%, and 5.1% from the time of treatment, 3 years after treatment, and 5 years after treatment, respectively. Upon multivariate analysis, multiple tumors, maximal tumor size ≥3 cm, and high Model for End-Stage Liver Disease scores were independently associated with increased HCC recurrence risk from the time of treatment and 1 and 2 years after curative treatment (all p<0.05, except for maxi-mal tumor size ≥3 cm for recurrence 2 years after treatment). Meanwhile, liver cirrhosis and RFA were independently associated with the increased HCC recurrence risk for almost all time points (liver cirrhosis: all p<0.05; RFA: all p<0.005 except for recurrence from 5 years after treatment). Conclusions The recurrence rate of HCC after curative treatment gradually decreased over time. Two years after treatment, when tumor-related factors lose their prognostic implications, may be used as a cutoff to define the boundary between early and late recurrence of HCC.

Viral hepatitis is the most important cause of acute and chronic liver disease in Korea.Particularly, hepatitis B virus (HBV) is the leading cause of liver-related mortality. Because of the nationwide vaccinations in the 1980s, hepatitis B surface antigen positive rates substantially decreased from 8% to 3%. Moreover, the introduction of potent nucleoside or nucleotide analogs led to the effective treatment of patients who had already been infected by HBV. The remaining issue has been to develop novel drugs that can cure HBV infection.Hepatitis C virus (HCV), on the other hand, is a hepatotropic virus that is parenterally transmitted. In Korea, the prevalence of HCV is estimated to be approximately 1%. Although no effective vaccine for HCV has been developed yet, highly effective and safe direct-acting antiviral therapy, which has a short treatment duration of 8 – 12 weeks, has made HCV eradication possible globally. Currently, the unsolved issue regarding HCV management is low disease awareness among patients and health care providers. Therefore, nationwide testing for anti-HCV would be a solution to identify patients infected with HCV but with no symptoms. Lastly, the Hepatitis A virus (HAV) is orally transmitted and results in acute hepatitis. In Korea, the young adult population is a high-risk group since this group is not vaccinated against HAV. More active vaccination and improved hygiene would be necessary to prevent HAV infection.

Background: Since September 2015, the initiation of antiviral therapy (AVT) for patients with chronic hepatitis B (CHB)-related cirrhosis has been reimbursed according to the revised Korean Association for the Study of Liver (KASL) guideline, if the patient had hepatitis B virus DNA level ≥ 2,000 IU/L, regardless of aminotransferase or alanine aminotransferase levels. This study investigated whether the KASL guideline implementation reduced the risk of CHB-related hepatocellular carcinoma (HCC) in patients with cirrhosis in South Korea. Methods: A total of 429 patients with CHB-related cirrhosis who initiated AVT between 2014 and 2016 were recruited. The risk of HCC development was compared between patients who initiated AVT before and after September 2015 (pre-guideline [n = 196, 45.7%] vs. postguideline implementation [n = 233, 54.3%]). Results: Univariate analysis showed that AVT initiation before guideline implementation, older age, male gender, and diabetes significantly predicted increased risk of HCC development (all P < 0.05). Subsequent multivariate analysis showed that AVT initiation before guideline implementation (HR = 1.941), older age (HR = 5.762), male gender (HR = 2.555), and diabetes (HR = 1.568) independently predicted increased risk of HCC development (all P < 0.05). Additionally, multivariate analysis showed that AVT initiation before guideline implementation (HR = 2.309), male gender (HR = 3.058), and lower platelet count (HR = 0.989) independently predicted mortality (P < 0.05). The cumulative incidences of HCC and mortality were significantly higher in patients who initiated AVT before guideline implementation than in those who initiated AVT after guideline implementation (all P < 0.05, log-rank test). Conclusion The prognosis of patients with CHB-related cirrhosis who initiated AVT improved after guideline implementation according to the revised KASL guideline.

Background/Aims: Besifovir dipivoxil maleate (BSV), an acyclic nucleotide phosphonate, shows potent antiviral activity against hepatitis B virus. Our previous 48-week trial revealed that BSV has comparable antiviral efficacy to tenofovir disoproxil fumarate (TDF) and better safety profiles in terms of improved renal and bone safety. This extension study evaluated the prolonged efficacy and safety of BSV in treatment-naive chronic hepatitis B patients. Methods: Patients continued to participate in an open-label BSV study after an initial 48-week double-blind comparison of BSV and TDF treatment. The antiviral efficacy and drug safety was evaluated up to 192 weeks in two groups: patients continuing BSV treatment (BSV-BSV) and patients switching from TDF to BSV after 48 weeks (TDF-BSV). Results: Among 197 patients receiving randomized treatments, 170 (86%) entered the open-label phase and 152 (77%) entered the 192-week extension study. Virological response rates over 192 weeks were 92.50% and 93.06% in the BSV-BSV and TDF-BSV groups, respectively (P=0.90). Hepatitis B envelop antigen seroconversion and alanine aminotransferase normalization rates were similar between the groups (P=0.75 and P=0.36, respectively). There were no drug-resistant mutations to BSV. Bone mineral density and renal function were well preserved in the BSV-BSV group, whereas these initially worsened then recovered after switching therapy in the TDF-BSV group. Conclusions BSV maintained potent antiviral efficacy after 192 weeks and showed no evidence of drug resistance. BSV was safe, well tolerated, and effective in patients who switched from TDF to BSV. Trial Registration Number: NCT01937806 (date: 10 Sep 2013).

Background/Aims: The immune-tolerant (IT) phase of chronic hepatitis B (CHB) patients is not generally indicative of antiviral therapy (AVT). We assessed and compared the risk of hepatocellular carcinoma (HCC) during the IT-phase stringently defined by a low fibrosis-4 (FIB-4) index, compared to that in patients undergoing AVT. Methods: Among 125 untreated patients that were hepatitis B e-antigen positive, hepatitis B virus-DNA >20,000 IU/mL, with normal alanine aminotransferase level from 2012 to 2018, those with a FIB-4 index of <1.45 were classified into the IT-group. The cumulative probability of HCC was estimated using Kaplan-Meier analysis. All patients were assessed until HCC development (intention-to-treat [ITT] analysis), whereas those suspected of experiencing CHB phase switch were assessed using the per-protocol (PP) and censored at the time of phase switch. Results: The cumulative probability of HCC at 1-, 3-, and 5-years among the IT-group was zero, compared to AVT-treated patients with FIB-4 indices <1.45 during the same period: 0.2%, 0.6%, and 1.4%, respectively (P=0.264 for ITT and P=0.533 for PP). Among the initially screened 125 untreated patients, those with a FIB-4 index of ≥1.45 had a higher risk of HCC compared to the IT-group (P=0.005). Furthermore, among AVT-treated patients, those with a FIB-4 index of ≥1.45 had a higher risk of HCC compared to their counterpart (P<0.001). Conclusions The risk of HCC was negligible in the IT-group stringently defined by a low FIB-4 index. However, given that a higher HCC risk exists among untreated patients with higher FIB-4, appropriate criteria for AVT should be established.