The current standard of care for patients with chronic hepatitis C virus (HCV) infection is a combination of direct-acting antiviral agents (DAAs). Most HCV patients treated with these drugs achieve viral elimination, but 1% to 15% fail to attain this objective. Treatment failures are usually related to relapse, and less often to on-treatment viral breakthrough. HCV drug resistant associated substitutions are detected in most patients who do not eliminate the virus. The risk of developing these variants depends on host- and virus-related factors, the properties of the drugs used, and the treatment strategies applied. Patients who carry Resistant Associated Substitutions (RASs) may not obtain benefits from treatment, and are at a risk of disease progression. Whether HCV RASs persist depends on their type: NS3-4A variants often disappear gradually after DAA therapy is stopped, whereas NS5A variants tend to persist for more than 2 years. The best way to prevent emergence of resistant variants is to eliminate the virus at the first treatment using highly potent DAAs with genetic barriers to resistance. For those who fail an NS5A inhibitor, deferral of treatment is recommended pending the availability of additional data if they do not have cirrhosis or reasons for urgent re-treatment. If re-treatment is needed, the most commonly used strategy is sofosbuvir as backbone therapy plus a drug from a class other than that previously used, for 24 weeks. Unless it is contraindicated, weight-based ribavirin should also be added. If available, nucleotide-based (eg, sofosbuvir) triple or quadruple DAA regimens may be considered. The optimal treatment for patients who fail an NS5A inhibitor and those with multidrug-resistant variants remains to be defined, and research efforts should continue to focus on treatment for these patients.
Antiviral Agents/*therapeutic use ; Drug Resistance, Viral ; Drug Therapy, Combination ; Genotype ; Hepacivirus/genetics ; Hepatitis C, Chronic/*drug therapy ; Humans ; Recurrence ; Ribavirin/therapeutic use ; Sofosbuvir/therapeutic use

Ever since direct-acting antiviral agents (DAA) have been approved and released into the world, numerous studies on the efficacy, adverse effects and drug-drug interactions of interferon-free DAA combination therapy have been studied and published. With all oral DAA therapy showing sustained virological response rate of 80-90% with minimal adverse events, HCV eradication has now become a realistic goal. DAA combination treatments were approved and adapted to practice in Korea in 2015, and Korean Association for the Study of the Liver (KASL) has revised the guideline based on the systematic approach that reflects evidence-based medicine and expert opinions. In this article, new recommendations for treatment of chronic HCV genotype 2 and 3 infected patients will be introduced base on KASL practice guidelines for management of hepatitis C that has been updated in 2015.
Antiviral Agents/*therapeutic use ; Drug Therapy, Combination ; Genotype ; Hepacivirus/*genetics/isolation & purification ; Hepatitis C/*drug therapy/virology ; Humans ; Interferon-alpha/therapeutic use ; Practice Guidelines as Topic ; Republic of Korea ; Ribavirin/therapeutic use ; Sofosbuvir/therapeutic use

The introduction of direct-acting antiviral agents (DAAs) has markedly improved the sustained virological response (SVR) rates in patients with chronic hepatitis C. Currently, four classes of DAAs targeting three HCV proteins (NS3, NS5A, and NS5B) have been approved for treatment in many countries. Since drugs show advantages and disadvantages, use of a combination of two or more DAAs with different targets or addition of ribavirin in a difficult-to-treat patient shows an SVR rate of ~90% after 12 weeks of treatment or expanded treatment for 24 weeks. Various types of DAA are awaiting approval which will improve the treatment of chronic hepatitis C virus genotype 1 infection. However, high costs, drug resistance and interactions between various drugs remain to be overcome. With further advances in the development of antiviral agents, it could be expected that in the near future, there will be DAAs that are affordable and cost effective, require shorter treatment duration, effective in a broad range of patients, and have less side effects and drug-drug interactions.
Antiviral Agents/*therapeutic use ; Drug Therapy, Combination ; Genotype ; Hepacivirus/*genetics/isolation & purification ; Hepatitis C/*drug therapy/virology ; Humans ; Interferon-alpha/therapeutic use ; Practice Guidelines as Topic ; Quinoxalines/therapeutic use ; Republic of Korea ; Sofosbuvir/therapeutic use

BACKGROUND/AIMS: The previous standard treatment for chronic hepatitis C (CHC) patients, comprising a combination of pegylated interferon (IFN) and ribavirin, was associated with suboptimal efficacy and severe adverse reactions. A new era of direct-acting antivirals is now dawning in Korea. Early experience of applying sofosbuvir-based therapy to CHC patients in Korea is reported herein. METHODS: Data on efficacy and safety were collected for CHC patients treated with a combination of sofosbuvir plus ribavirin or sofosbuvir/ledipasvir with or without ribavirin. RESULTS: This retrospective study included 25 consecutive patients who received sofosbuvir-based therapy (19 with genotype 1b and 6 with genotype 2) at Seoul National University Hospital from May 2014 to April 2015. A virologic response was achieved at week 4 by 85.7% and 80% of the patients with genotypes 1b and 2, respectively. The HCV-RNA level decreased more slowly in IFN-experienced than in treatment-naive patients with genotype 1b. However, the sustained virologic response at week 12 (SVR12) rate did not differ among these patients, and was as high as 100%. The presence of cirrhosis significantly increased the risk of a virologic response failure at week 4 (OR, 11.0; P=0.011) among patients with HCV genotype 1b. Only five patients (20%) experienced minor adverse events, including grade 1 fatigue and headache. The hemoglobin level decreased slightly after sofosbuvir-based therapy, but there was no case of premature discontinuation of this therapy. CONCLUSIONS: In a real clinical practice, sofosbuvir-based therapy for CHC patients in Korea achieved optimal antiviral efficacy with insignificant adverse events. Long-term follow-up data are warranted to ensure the sustained antiviral efficacy and long-term safety of sofosbuvir-based IFN-free therapy.
Adult ; Aged ; Aged, 80 and over ; Antiviral Agents/adverse effects/*therapeutic use ; Drug Therapy, Combination ; Fatigue/etiology ; Female ; Genotype ; Headache/etiology ; Hemoglobins/analysis ; Hepacivirus/genetics ; Hepatitis C, Chronic/complications/*drug therapy/virology ; Humans ; Liver Cirrhosis/complications/diagnosis ; Male ; Middle Aged ; RNA, Viral/blood ; Republic of Korea ; Retrospective Studies ; Ribavirin/therapeutic use ; Sofosbuvir/adverse effects/*therapeutic use ; Treatment Outcome

Objective: To evaluate the real-world efficacy and safety of sofosbuvir and velpatasvir (SOF/VEL) tablets in the treatment of Chinese patients with chronic HCV infection. Methods: An open-label, single-center, prospective clinical study was conducted in a county in northern China. A total of 299 cases were enrolled. Of these, 161 cases with chronic hepatitis C and 73 cases with compensated cirrhosis received SOF/VEL for 12 weeks. 65 cases with decompensated cirrhosis received SOF/VEL combined with ribavirin for 12 weeks (22 cases) or SOF/VEL for 24 weeks (43 cases). Virological indicators, liver and renal function indexes, and liver stiffness measurement were detected at baseline, the fourth week of treatment, the end of treatment, and the 12-weeks of follow-up. Adverse reactions and laboratory abnormalities were observed during the course of treatment . The primary endpoint was undetectable rate of HCV RNA (SVR12) at 12 weeks of follow-up with the use of modified intention-to-treat (mITT) approach. Measurement data between two groups were compared using t-test. One Way ANOVA was used for comparison between multiple groups. Enumeration data were analyzed by chi-square test or Fisher's exact test. Results: 291 cases had completed treatment. HCV RNA was undetectable after 12 weeks of follow-up, and the SVR12 rate was 97.3% (95% confidence interval: 95.4%-99.3%). Among them, 97.4% of genotype 1b, 96.4% of genotype 2a, and 100% of those with undetected genotype achieved SVR12. The SVR12 rates in patients with chronic hepatitis C, compensated and decompensated liver cirrhosis were 98.1%, 98.6% and 93.8%, respectively. An improvement in alanine aminotransferase, aspartate aminotransferase and other liver biochemical indicators accompanied with virological clearance and reduced liver stiffness measurement was observed in patients with compensated cirrhosis, with statistically significant difference. There was no significant abnormality in renal function before and after treatment. The most common adverse reactions were fatigue, headache, epigastric discomfort and mild diarrhea. The overall adverse reactions were mild. One patient died of decompensated liver cirrhosis combined with massive upper gastrointestinal bleeding, which was unrelated to antiviral treatment. Four patients discontinued treatment prematurely due to adverse events. Relapse was occurred in four cases, and drug-resistance related mutations were detected in three cases. Conclusion: Sofosbuvir and velpatasvir tablets in Chinese HCV-infected patients with different genotypes, different clinical stages or previously treated with pegylated interferon combined with ribavirin resulted in higher SVR12, indicating that the treatment safety profile is good.
Antiviral Agents/therapeutic use* ; Carbamates ; Drug Therapy, Combination ; Genotype ; Hepacivirus/genetics* ; Hepatitis C/drug therapy* ; Hepatitis C, Chronic/drug therapy* ; Heterocyclic Compounds, 4 or More Rings ; Humans ; Liver Cirrhosis/complications* ; Prospective Studies ; RNA ; Ribavirin/therapeutic use* ; Sofosbuvir/adverse effects* ; Sustained Virologic Response ; Treatment Outcome