Hepatitis C virus protease inhibitor-resistance mutations: Our experience and review

Direct-acting antiviral agents(DAAs)for hepatitis C virus(HCV)infection are one of the major advances in its medical treatment.The HCV protease inhibitors boceprevir and telaprevir were the first approved DAAs in the United States,Europe,and Japan.When combined with peginterferon plus ribavirin,these agents increase sustained virologic response rates to70%-80%in treatment-na?ve patients and previoustreatment relapsers with chronic HCV genotype 1 infection.Without peginterferon plus ribavirin,DAA monotherapies increased DAA-resistance mutations.Several new DAAs for HCV are now in clinical development and are likely to be approved in the near future.However,it has been reported that the use of these drugs also led to the emergence of DAA-resistance mutations in certain cases.Furthermore,these mutations exhibit cross-resistance to multiple drugs.The prevalence of DAA-resistance mutations in HCV-infected patients who were not treated with DAAs is unknown,and it is as yet uncertain whether such variants are sensitive to DAAs.We performed a population sequence analysis to assess the frequency of such variants in the sera of HCV genotype 1-infected patients not treated with HCV protease inhibitors.Here,we reviewed the literature on resistance variants of HCV protease inhibitors in treatment na?ve patients with chronic HCV genotype 1,as well as our experience.     

Short-term antiviral efficacy of BILN 2061, a hepatitis C virus serine protease inhibitor, in hepatitis C genotype 1 patients

BACKGROUND AND AIMS: Novel, potent, and well-tolerated hepatitis C virus (HCV) drugs are needed. BILN 2061 is a potent and specific inhibitor of HCV serine protease in vitro. Preclinical toxicology data and studies in healthy volunteers supported the administration of BILN 2061 to patients with HCV infection. METHODS: The antiviral efficacy, pharmacokinetics, and tolerability of 25, 200, and 500 mg BILN 2061 twice daily given as monotherapy for 2 days in 31 patients infected with chronic genotype 1 HCV infection and with minimal liver fibrosis (Ishak score of 0-2) were assessed in a placebo-controlled, double-blind pilot study. In 2 subsequent placebo-controlled studies of similar design, 200 mg BILN 2061 twice daily was administered for 2 days to 10 patients with advanced liver fibrosis (Ishak score of 3 or 4) and to 10 patients with compensated cirrhosis (Ishak score of 5 or 6). RESULTS: Viral RNA reductions of 2-3 log 10 copies/mL were achieved in most of the patients. There was a trend toward a higher number of patients receiving 500 mg BILN 2061 achieving a viral RNA reduction > or =3 log(10) copies/mL as compared with patients receiving 25 mg BILN 2061. Advanced fibrosis or compensated cirrhosis did not affect the antiviral efficacy of BILN 2061. BILN 2061 was well tolerated in all studies. CONCLUSIONS: BILN 2061 is a well-tolerated and very active compound that reduced serum viral RNA concentrations after 2 days of treatment in patients infected with genotype 1 HCV independent of the degree of fibrosis. Nevertheless, further clinical trials are on hold pending resolution of animal toxicity issues.     

Clinical significance of pre-S mutations in patients with genotype C hepatitis B virus infection

We investigated the overall and site-specific prevalence of pre-S mutations and its clinical significance in patients with genotype C hepatitis B virus (HBV) infection. Three hundred subjects were included: 50 asymptomatic carriers (AC), 87 chronic hepatitis (CH), 91 liver cirrhosis (LC) and 72 hepatocellular carcinoma (HCC). Pre-S mutations were determined by nucleotide sequence analysis. Possible correlations between pre-S mutations and clinical/virological parameters were examined. Pre-S mutations were detected in 82 cases (27.3%); it was more frequently found in HCC (43.1%) and LC (35.2%) group than in the CH (20.7%) and AC (2.0%) group. Pre-S2 deletion was the most commonly found mutation (10.7%), followed by pre-S2 start codon mutation (9.7%), pre-S1-S2 deletion (3.0%) and both pre-S2 deletion and start codon mutation (2.7%). Pre-S2 deletion and pre-S2 start codon mutation were more frequently detected in advanced diseases (LC and HCC). Pre-S mutations were associated with older age and higher rates of positive HBV DNA (>/=0.5 pg/mL). Advanced disease and positive HBV DNA were shown to be independent predictors of pre-S mutations by logistic regression analysis. These findings suggest that pre-S mutations, especially pre-S2 deletions and pre-S2 start codon mutations, are common in patients with genotype C HBV infection and are associated with advanced liver disease and active viral replication.     

Characterization of full-length hepatitis C virus genotype 4 sequences

Over 85% of the world's nearly 170 million hepatitis C virus (HCV)-infected subjects exist in regions of Africa, Southeast Asia and Middle Eastern countries where genotypes 4-6 are very common. In particular, HCV genotype 4 is highly prevalent in Egypt with more than 19% of the population infected and chronic HCV representing one of the top five leading causes of death, due in part to ineffective interferon alpha treatment against this genotype. Despite this, very little work has been carried out to characterize the sequence diversity of genotype 4, which will be critical to the development of effective vaccines and antiviral therapies against this genotype. As a result of the paucity of sequence data available for HCV genotype 4, for which only one full genome sequence is currently available, we were interested in characterizing additional genotype 4 sequences and to provide reagents for amplification of this genotype. Here we describe seven unique HCV genotype 4a full genomes, in addition to a single genotype 4d genome, and characterize their sequence diversity in relation to other more closely characterized HCV genotypes.     

Replacement of hepatitis C virus genotype 1b by genotype 2 over a 10-year period in Venezuela

BACKGROUND: Changes in hepatitis C virus (HCV) genotype distribution with time have been reported in several countries. GOALS: To explore eventual changes in HCV genotype distribution in Venezuela over a 10 years period. STUDY: HCV genotype was determined by direct sequencing of the 5' noncoding region, in 236 isolates circulating in patients treated during years 2005 to 2006. Genotype distribution was compared with the one observed in 43 patients followed during years 1994 to 1996. RESULTS: The prevalence HCV genotype 1 and 2 was 70% and 26%, respectively, in patients followed during years 1994 to 1996. The frequency of genotype 2 was significantly increased to 41% (P=0.04) in patients treated during years 2005 to 2006. A significant reduction in HCV genotype 1b prevalence (48% to 27%, P=0.01) was also observed after this 10 years period, whereas the prevalence of HCV genotype 1a did not change over time (22% vs. 27%, NS). Transfusion was more significantly associated with infection with HCV genotype 1b than with other genotypes (52% vs. 20%, P=0.002). CONCLUSIONS: HCV subtype 1b seems to have been displaced by HCV genotype 2 in a relatively short period, without increase in the frequency of genotype 3. The low frequency of HCV genotype 3 in Venezuela might be due to the fact that intravenous drug use in Venezuela is less common than in other countries. The implementation of anti-HCV testing in blood banks since 1994 in Venezuela, might have contributed to the reduction in the frequency HCV genotype 1b infection.     

An infectious molecular clone of a Japanese genotype 1b hepatitis C virus.

We describe an infectious molecular clone of a Japanese genotype 1b strain of hepatitis C virus (HCV-N). The molecularly cloned sequence of HCV-N was compared with alignments of other HCV sequences, leading to the identification of 15 unique, nonconservative amino acid substitutions within the HCV-N open reading frame (ORF). These were repaired to the consensus genotype 1b residue, and the infectivity of RNA transcribed from the repaired clone was assessed by intrahepatic inoculation of a chimpanzee. Viral RNA was first detected in the serum of this chimpanzee 3 weeks following inoculation, and was intermittently present over the next 14 weeks. A strong and persistent anti-HCV serological response developed 13 weeks following inoculation, with seroconversion in the recombinant immunoblot assay (RIBA). A weaker, transient serological response, characterized by seroconversion in a third-generation enzyme-linked immunosorbent assay (ELISA) but not RIBA, occurred between weeks 1 and 5. This may have represented an anamnestic response to HCV antigens translated directly from the intrahepatically inoculated RNA, because the animal previously had undergone 2 unsuccessful attempts at rescue of HCV by intrahepatic RNA inoculation. There was neither biochemical nor histological evidence of liver disease. Although this is within the range of expected outcomes in an HCV-naive chimpanzee, prior immunologic priming may have modified the infection in this animal. The HCV-N clone is the first infectious molecular clone of HCV that is comprised entirely of genotype 1b sequence, and it contains an ORF sequence that is significantly divergent from that of a previously described genotype 1a/1b chimera.     

SCH 503034, a novel hepatitis C virus protease inhibitor, plus pegylated interferon alpha-2b for genotype 1 nonresponders

BACKGROUND & AIMS: SCH 503034 is a novel and potent oral hepatitis C virus (HCV) protease inhibitor. In this phase Ib study, we assessed safety parameters and virologic response of combination of SCH 503034 plus pegylated (PEG) interferon (IFN) alpha-2b in patients with HCV genotype 1 infections who were previously nonresponders to PEG-IFN-alpha-2b +/- ribavirin therapy. METHODS: This was a multicenter, open-label, 2-dose level, 3-way crossover, randomized (to crossover sequence) study carried out in 3 medical centers in Europe. Adult patients received SCH 503034 200 mg (n = 14) or 400 mg (n = 12) 3 times daily orally and PEG-IFN-alpha-2b 1.5 microg/kg subcutaneously once each week. Patients received SCH 503034 as monotherapy for 1 week, PEG-IFN-alpha-2b as monotherapy for 2 weeks, and combination therapy for 2 weeks with washout periods between each treatment period. RESULTS: Combination therapy with SCH 503034 and PEG-IFN-alpha-2b was well tolerated, with no clinically significant changes in safety parameters. Mean maximum log(10) changes in HCV RNA were -2.45 +/- 0.22 and -2.88 +/- 0.22 for PEG-IFN-alpha-2b plus 200 mg and 400 mg SCH 503034, respectively, compared with -1.08 +/- 0.22 and -1.61 +/- 0.21 for SCH 503034 200 mg and 400 mg, respectively, and -1.08 +/- 0.22 and -1.26 +/- 0.20 for PEG-IFN-alpha-2b alone in the 200 mg and 400 mg SCH 503034 groups, respectively. CONCLUSIONS: SCH 503034 plus PEG-IFN-alpha-2b was well tolerated in patients with HCV genotype 1 nonresponders to PEG-IFN-alpha-2b +/- ribavirin. These preliminary results of antiviral activity of the combination suggest a potential new therapeutic option for this hard-to-treat, nonresponder patient population.     

Safety and efficacy of elbasvir and grazoprevir in Japanese hemodialysis patients with genotype 1b hepatitis C virus infection

Journal of Gastroenterology - The prevalence of hepatitis C virus (HCV) infection in hemodialysis patients is high and results in a poor prognosis. Thus, safer and more effective treatment regimens...     

Successful treatment of three patients with human immunodeficiency virus and hepatitis C virus genotype 1b co-infection by daclatasvir plus asunaprevir

Co-infection with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) often accelerates the course of HCV-associated liver disease. Daclatasvir (DCV) plus asunaprevir (ASV) have been shown to be highly effective for HCV-infected patients with genotype 1b. Three patients co-infected with HIV/HCV genotype 1b were enrolled in this study. Prior to initiation of HCV treatment, the variants associated with L31 and Y93 in the non-structural protein 5A (NS5A) region of the HCV genome were confirmed to be absent using a direct sequencing method. Taking into consideration the lower risk of drug–drug interaction and the need for immediate treatment, the patients received 60 mg DCV once daily plus 100 mg ASV twice daily for 24 weeks. In one patient, the alanine aminotransferase level was elevated to 228 IU/L at 24 weeks after the start of treatment, but he completed the 24-week treatment course. All three patients achieved sustained viral response, without severe complications (including HIV virological rebound). Thus, in cases where NS5A variants are confirmed to be absent and patients are antiretroviral therapy-naïve, with CD4+ over 500/μL or HIV well controlled by RAL-based cART, DCV plus ASV may represent a good treatment option for HIV and HCV genotype 1b co-infected patients.     

Improving outcome in patients with hepatitis C virus genotype 4

Several factors influence treatment outcomes among patients with chronic hepatitis C. A trend is growing to adapt an individualized treatment approach to optimize treatment outcomes among chronic hepatitis C patients. Hepatitis C virus (HCV) genotype is an important factor that determines treatment outcomes among patients with chronic hepatitis C. HCV has six genotypes, and genotype 4 (G4) accounts for 20% of all global HCV infections. Patients with G4 are underrepresented in clinical trials involving patients with chronic hepatitis C because most patients infected with G4 are in Egypt, Africa, and Middle Eastern countries. Therefore, there is little information about the predictors of response to standard treatment among chronic hepatitis C patients with HCV G4. Initial evidence suggested that patients with G4 HCV are as difficult to treat as patients with G1; however, recent evidence suggests that the response rates to treatment among patients with G4 may be better than those with G1 but not those with G2 or G3. This review discusses the clinical data among patients with G4 and assesses the impact of an individualized approach on improved treatment outcomes in these patients.     

Lamivudine resistance mutations in patients infected with hepatitis B virus genotype D

AIM: To determine the distribution of viral genotypes for primary or acquired lamivudine resistance. METHODS: A total of 283 patients with chronic hepatitis B virus (HBV) infection (245 patients with chronic hepatitis B and 38 inactive hepatitis B surface antigen carriers) were included in the study. The HBV geno-type was determined by using quantitative real-time polymerase chain reaction and sequence analysis, and tyrosine-methionine-aspartate-aspartate (YMDD) motif mutations were determined using the rev...     

Serum lipid profile of patients with genotype 1b hepatitis C viral infection in Japan

Hepatitis C virus (HCV) infection is associated with the development of steatosis in the liver. Recently, infection with genotype 3a HCV has been reported to have a closer association with hepatic steatosis than that with genotype 1 or 2 HCV. Moreover, infection with genotype 3a HCV but not with genotype 1 has been shown to be associated with serum hypocholesterolemia or hypobetalipoproteinemia in European countries. We conducted a case control study to characterize the serum lipid profile in patients infected with genotype 1b HCV, which is the most prevalent HCV genotype in Japan. These patients had significantly lower serum cholesterol levels than those infected with HBV or genotype 2a HCV who had similar liver disease progression and body mass index. Further analysis of serum apolipoproteins revealed that not only apolipoprotein B but also apolipoprotein CII and apolipoprotein CIII levels were significantly reduced, while apolipoprotein AI, AII and E levels were similar in patients infected with genotype 1b HCV and those with HBV or genotype 2a HCV. These results indicate that, in Japan, infection with genotype 1b HCV is a cause of lipid metabolism disturbances, which may be associated with the pathogenesis of hepatitis C liver disease.