Predictive value of the IL28B polymorphism on the effect of interferon therapy in chronic hepatitis C patients with genotypes 2a and 2b

A Comprehensive Review of Antiviral Therapy for Hepatitis C: The Long Journey from Interferon to Pan-Genotypic Direct-Acting Antivirals (DAAs)

The treatment landscape for hepatitis C virus (HCV) infection has transformed over the past few decades, evolving from the limited efficacy of interferon (IFN) monotherapy to the highly successful pan-genotypic direct-acting antivirals (DAAs) used today. Initially, alpha-interferon monotherapy, introduced in the 1990s, was the standard treatment, yet it provided low sustained virological response (SVR) rates and caused significant adverse effects, limiting its utility. The development of pegylated interferon (peg-IFN) improved the pharmacokinetic profile of IFN, allowing for less frequent dosing and modestly improved response rates. When combined with ribavirin, peg-IFN achieved higher SVR rates, especially in non-genotype 1 HCV infections, but the combination also brought additional side effects, such as anemia and depression. The advent of the first-generation DAAs, such as telaprevir and boceprevir, marked a significant milestone. Combined with peg-IFN and ribavirin, these protease inhibitors boosted response rates in patients with genotype 1 HCV. However, high rates of adverse effects and drug resistance remained challenges. Second-generation DAAs, like sofosbuvir and ledipasvir, introduced IFN-free regimens with improved safety profiles and efficacy. The most recent advances are pan-genotypic DAAs, including glecaprevir-pibrentasvir and sofosbuvir-velpatasvir, which offer high SVR rates across all genotypes, shorter treatment durations, and fewer side effects. Current pan-genotypic regimens represent a cornerstone in HCV therapy, providing an accessible and effective solution globally.

Impact of Interleukin 28B and ICAM-1 Genetic Polymorphisms on Response to Direct Antiviral Treatment Among HCV Infected Patients

BACKGROUND

Single nucleotide polymorphisms (SNPs) of IL-28B and/or ICAM-1 could have a role in expecting a response from HCV infected patients to direct antiviral agents (DAAs).

OBJECTIVE

The aim of the current study was to investigate the impact of IL-28B rs12979860 and rs8099917, and, ICAM-1 rs281437 SNPs on response to treatment with sofosbuvir + Daclatsvir ± Ribavirin, among HCV-infected Egyptian patients.

METHODS

Whole blood genomic DNA was extracted from 120 participants (80 HCV-infected patients and 40 healthy volunteers). HCV-infected patients were subdivided into responders and nonresponders to DAAs. Liver function testing, anti-HCV antibodies, HCV-RNA viral load and HCV genotyping were performed. IL-28B and ICAM-1 SNPs were evaluated by real-time PCR.

RESULTS

ALT and AST levels were significantly higher among non-responder HCV infected patients (P = 0.001*). 90% of the patients had HCV genotype 4a and the remaining 10% had 4l genotype. Allelic discrimination revealed that IL-28B rs12979860 T, IL-28B rs809917 T and ICAM-1 rs281437 C alleles were more frequent among HCV-infected patients (responders or non-responders) than controls. However, IL-28B rs8099917 G allele was more frequent among healthy controls. Regarding the response to DAAs treatment, HCV-infected patients with IL-28B rs8099917 GG genotype showed a significantly earlier viral response compared to those carrying TT alleles. ICAM-1 rs281437 CT alleles were non significantly more frequent among responders. However, IL-28B rs12979860 alleles did not show any difference.

CONCLUSION

Genotyping of IL-28B rs8099917 is a useful independent tool for expecting a response of Egyptian HCV-infected patients to DAAs.

The impact of interferon-free direct-acting antivirals on clinical outcome after curative treatment for hepatitis C virus-associated hepatocellular carcinoma: Comparison with interferon-based therapy

BACKGROUND AND AIM

To examine the effect on recurrence and survival of treatment by interferon (IFN)-free direct-acting antivirals (DAA) for patients with hepatitis C virus (HCV)-associated hepatocellular carcinoma (HCC) who underwent primary curative treatment.

METHODS

This was a retrospective cohort study of 250 patients with HCV who had received curative treatment for primary HCC. As anti-HCV treatment after HCC treatment, 38 patients received IFN-free DAA therapy (DAA patients) and 94 received IFN-based therapy (IFN patients). The recurrence of HCC and overall survival of the patient groups were compared in a case-control study.

RESULTS

The cumulative HCC recurrence rates at 1, 3, and 5 years were 5%, 39%, and 39% for DAA patients and 0%, 46%, and 62% for IFN patients, respectively (P = 0.370). Multivariate analysis of the HCC recurrence identified treatment responses (sustained virological response [SVR]: hazard ratio [HR] 2.237; P = 0.003) as an independent predictive factor. The cumulative overall survival rates at 3 and 5 years were 96%, 96% for DAA patients and 93%, 73% for IFN patients, respectively ( P = 0.163). Multivariate analysis identified treatment responses (SVR: HR 8.742; P < 0.001) as independent predictors of overall survival. Propensity score matching analysis showed no significant difference in HCC development rates and overall survival rates in the two groups.

CONCLUSIONS

We found that SVR obtained after curative treatment for primary HCC suppressed recurrence and improved overall survival. And, IFN-free DAA therapy after curative treatment for primary HCC could predict improving overall survival and suppressed HCC recurrence.

Randomized Phase 3 Trial of Ombitasvir/Paritaprevir/Ritonavir and Ribavirin for Hepatitis C Virus Genotype 2-Infected Japanese Patients

INTRODUCTION

In Japan, hepatitis C virus (HCV) genotype (GT) 2 accounts for approximately 32% of HCV infections. Limited treatment options exist in Japan for HCV GT2-infected patients. GIFT-II was a phase 3, randomized, open-label study evaluating the efficacy and safety of 16- and 12-week regimens of co-formulated ombitasvir (OBV)/paritaprevir (PTV)/ritonavir (r) plus ribavirin (RBV) in Japanese adults with HCV GT2 infection.

METHODS

Patients were randomized in a 1:1 ratio to once-daily, co-formulated OBV/PTV/r (25/150/100 mg) with weight-based RBV for 16 or 12 weeks. The primary efficacy endpoint was the sustained virologic response at 12 weeks post-treatment (SVR12) rate in the primary efficacy population of non-cirrhotic treatment-naive patients.

RESULTS

A total of 171 patients were randomized to OBV/PTV/r + RBV. In the primary efficacy population, SVR12 rates were 91.5% (43/47; 95% confidence interval 83.5-99.5%) and 75.0% (36/48; 95% confidence interval 62.8-87.2%) in the 16-week arm and 12-week arm, respectively. No patient in the 16-week arm relapsed by post-treatment week 12. Among non-cirrhotic treatment-experienced patients, the overall SVR rate in the 16-week arm was 75.8% (25/33) and was highest [93.8% (15/16)] among those who had relapsed after previous interferon-based therapy. SVR12 rates were consistently higher in patients with HCV GT2a infection versus HCV GT2b infection [16-week treatment arm: 93.9% (31/33) versus 85.7% (12/14) and 93.8% (15/16) versus 56.3% (9/16) among non-cirrhotic treatment-naive and treatment-experienced patients, respectively]. No patient discontinued treatment because of an adverse event. The most common adverse events were anemia, increased blood bilirubin, and nasopharyngitis.

CONCLUSIONS

OBV/PTV/r + RBV for 16 weeks resulted in high SVR12 rates in non-cirrhotic Japanese patients infected with HCV GT2 who were treatment-naive or who had relapsed after an interferon-based therapy. Higher SVR12 rates were observed among patients with HCV GT2a infection versus those with GT2b infection. This regimen demonstrated a favorable safety profile.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT02023112.

FUNDING

AbbVie.

IFN-λ4 desensitizes the response to IFN-α treatment in chronic hepatitis C through long-term induction of USP18

The recently discovered interferon lambda 4 (IFN-λ4) is a new member of the human type III interferons which could induce a strong antiviral effect through the JAK-STAT cascade. However, hepatitis C virus (HCV) patients who are capable of expressing IFN-λ4 usually have poor response to IFN-α treatment, and the mechanism behind this paradox remains unknown. Here, we reported that IFN-λ4 desensitized IFN-α-stimulated JAK-STAT signalling. Microarray analysis revealed that IFN-λ4 could induce ubiquitin specific peptidase 18 (USP18), a known inhibitor of the type I IFN signalling pathway, in a more sustained pattern compared with type I interferon induction. Moreover, only HCV genotype 1b but not 2a replicon cells pretreated with IFN-λ4 had an attenuated response to type I IFN treatment, which might be due to the different level of USP18 expression. Consistently, knockdown of USP18 in HCV genotype 1b-containing replicon cells reversed the resistance induced by IFN-λ4 and promoted viral clearance. Finally, IFN-λ4 is also strongly associated with the poor response to IFN-α in a Chinese HCV genotype 1b cohort. In conclusion, these data indicate that IFN-λ4 attenuates the response of HCV genotype 1b to IFN-α therapy and inhibits the JAK-STAT signalling pathway by inducing USP18 expression.

Response to treatment following recently acquired hepatitis C virus infection in a multicentre collaborative cohort

Pegylated interferon therapy is highly effective in recently acquired HCV. The optimal timing of treatment, regimen and influence of host factors remains unclear. We aimed to measure sustained virological response (SVR) during recent HCV infection and identify predictors of response. Data were from five prospective cohorts of high-risk individuals in Australia, Canada, Germany and the United States. Individuals with acute or early chronic HCV who commenced pegylated interferon therapy were included. The main outcome was SVR, and predictors were assessed using logistic regression. Among 516 with documented recent HCV infection, 237 were treated (pegylated interferon n = 161; pegylated interferon/ribavirin n = 76) (30% female, median age 35 years, 56% ever injected drugs, median duration of infection 6.2 months). Sixteen per cent (n = 38) were HIV/HCV co-infected. SVR among those with HCV mono-infection was 64% by intention to treat; SVR was 68% among HCV/HIV co-infection. Independent predictors of SVR in HCV mono-infection were duration of HCV infection (the odds of SVR declined by 8% per month of infection, aOR 0.92, 95% CI 0.85-0.99, P = 0.033), IFNL4 genotype (adjusted OR 2.27, 95% CI 1.13-4.56, P = 0.021), baseline HCV RNA <400 000 IU/mL (aOR 2.06, 95% CI 1.03-4.12, P = 0.041) and age ≥40 years (vs <30: aOR 2.92, 95% CI 1.31-6.49, P = 0.009), with no difference by drug regimen, HCV genotype, symptomatic infection or gender. The effect of infection duration on odds of SVR was greater among genotype-1 infection. Interferon-based HCV treatment is highly effective in recent HCV infection. Duration of infection, IFNL4 genotype and baseline HCV RNA levels can predict virological response and may inform clinical decision-making.

C. P, Rai A, Dixit S. Prevalence of HIV, Hepatitis B and C Infections and an Assessment of HCV-Genotypes and Two IL28B SNPs among People Who Inject Drugs in Three Regions of Nepal

As part of a comprehensive health care programme for people who use drugs in Nepal, HIV and viral hepatitis B and C status--including risk factors, HCV-genotypes and co-infections--as well as two IL28B Single-nucleotide polymorphisms (SNPs) were assessed for a random sample of 401 people who inject drugs in three regions of Nepal: mid-western Terrai (Nepalgunj), the eastern region (Dharan, Biratnagar) and the central region (Kathmandu, Lalitpur and Chitwan). Individuals were included who showed at least a minimum of health care seeking behaviour. This latter criterion was defined by being registered with any organisation offering health services. The average age of the participants was 30.5 yrs, and the average length of intravenous drug use was 8.5 yrs. The prevalence rates of HBsAg, anti-HIV antibodies and HCV-RNA were 3.5%, 13.8% and 41.9%, respectively. Spontaneous HCV clearance was evident in 16% of all of those who tested positive for anti-HCV antibodies. Independent risk factors for HCV-RNA positivity were age, gender, geographical region, duration of injecting drug use, history of imprisonment and HIV co-infection. In the age group ≤24 yrs, the rate of spontaneous HCV clearance was 43.5%. Overall, 59.8% of HCV infections were caused by HCV genotype 3 and 40.2% by HCV genotype 1. No other HCV genotypes were identified in this study. The IL28B SNP rs12979860 and rs8099917 were identified in 122 patients, and 75.4% of all participants had both favourable genotypes rs12979860 C/C and rs8099917 T/T.

Efficacy of telaprevir-based therapy for difficult-to-treat patients with genotype 2 chronic hepatitis C in Japan

AIM

This study assessed the efficacy and safety of telaprevir in combination with peginterferon-α-2b (PEG IFN) and ribavirin (RBV), for Japanese difficult-to-treat patients with hepatitis C virus (HCV) genotype 2 who had not achieved sustained virological response (SVR) during prior treatment.

METHODS

In total, 108 relapsed (median age, 59.0 years) and 10 non-responding (median age, 59.0 years) patients with genotype 2 HCV participated. Patients received telaprevir (750 mg, every 8 h) for 12 weeks and PEG IFN/RBV for 24 weeks.

RESULTS

The SVR rates for relapsers and non-responders were 88.0% (95/108) and 50.0% (5/10), respectively. The SVR rates did not differ significantly between patients with rs8099917 TT and non-TT. The SVR rates for relapsers and non-responders with extended rapid viral response (eRVR) were 97.6% (82/84) and 100% (5/5), respectively. On the other hand, the SVR rates for relapsers and non-responders completing the treatment protocol were 98.4% (61/62) and 100% (5/5), respectively. The overall safety profiles of telaprevir-based regimens were similar for Japanese patients with genotype 1 and 2 HCV infection who experienced treatment failure.

CONCLUSION

Telaprevir, in combination with PEG IFN/RBV, provided a high SVR rate for genotype 2 HCV, difficult-to-treat patients who had not achieved SVR during prior IFN-based treatment. The eRVR had a strong influence on the cure rate of telaprevir-based therapy. In addition, the continuation of telaprevir-based treatment for up to 24 weeks was a significant predictor of SVR.

Randomized trial of interferon- and ribavirin-free ombitasvir/paritaprevir/ritonavir in treatment-experienced hepatitis C virus-infected patients

Approximately 2 million Japanese individuals are infected with hepatitis C virus and are at risk for cirrhosis, end-stage liver disease, and hepatocellular carcinoma. Patients in whom interferon (IFN)/ribavirin (RBV) therapy has failed remain at risk as effective therapeutic options are limited. This phase 2, randomized, open-label study evaluated an IFN- and RBV-free regimen of once-daily ombitasvir (ABT-267), an NS5A inhibitor, plus paritaprevir (ABT-450), an NS3/4A protease inhibitor dosed with ritonavir (paritaprevir/ritonavir), in pegylated IFN/RBV treatment-experienced Japanese patients with hepatitis C virus subtype 1b or genotype 2 infection. Patients without cirrhosis (aged 18-75 years) with subtype 1b infection received ombitasvir 25 mg plus paritaprevir/ritonavir 100/100 mg or 150/100 mg for 12 or 24 weeks; patients with genotype 2 infection received ombitasvir 25 mg plus paritaprevir/ritonavir 100/100 mg or 150/100 mg for 12 weeks. Sustained virologic response (SVR) at posttreatment week 24 (SVR24 ) was the primary endpoint. Adverse events were collected throughout the study. One hundred ten patients received ≥1 dose of study medication. In the subtype 1b cohort, SVR24 rates were high (88.9%-100%) regardless of paritaprevir dose or treatment duration. In the genotype 2 cohort, SVR24 rates were 57.9% and 72.2% with 100 mg and 150 mg of paritaprevir, respectively. The SVR24 rate was higher in patients with subtype 2a (90%) than 2b (27%). Concordance between SVR12 and SVR24 was 100%. The most common adverse events overall were nasopharyngitis (29%) and headache (14%).

CONCLUSION

In this difficult-to-treat population of patients in whom prior pegylated IFN/RBV had failed, ombitasvir/paritaprevir/ritonavir demonstrated potent antiviral activity with a favorable safety profile among Japanese patients with hepatitis C virus genotype 1b or 2a infection.

IL28B rs12980275 polymorphism shows association with response to treatment in Pakistani patients with chronic hepatitis C

The aim of this study was to describe the genetic characteristics of Pakistani patients infected with hepatitis C virus (HCV) in relation to IL28B polymorphisms and its association to interferon and ribavirin treatment response. A total of 220 patients, infected with HCV were enrolled, out of which 100 were responders and 120 were nonresponders. The whole blood samples were collected to extract viral RNA and genomic DNA. PCR following the restriction fragment length polymorphism method was used to genotype IL28B rs12979860, rs8099917, and rs12980275 polymorphisms. Liver biopsies and HCV genotyping were performed in nonresponder patients. The rs12980275 AA genotype exhibited significant correlation to treatment response and was found in 62% of the responders and 37.5% of nonresponder patients, whereas AG genotype was noticed frequently in the nonresponder group (P < 0.0001). The rs12979860 CT and rs8099917 TT genotypes were found in 74% and 66% of the responders as compared to 58.3% and 50.8% in nonresponder patients (P = 0.001 and P = 0.032) respectively. HCV 3a genotypes were detected in 50.8% of the nonresponder patients. No significant association was detected between liver biopsy findings and IL28B SNPs (P > 0.05). The results showed the significant association of rs12980275 polymorphism with treatment response in HCV patients followed by rs12979860 and rs8099917. This is the first report describing the association of rs12980275 with response to HCV treatment from Pakistan. These findings may help in predicting the outcome of pegylated interferon and ribavirin treatment in HCV patients, and may reduce the side effects and cost of treatment in predicting non-responder patients.

Interferon-λ3 polymorphisms in pegylated-interferon-α plus ribavirin therapy for genotype-2 chronic hepatitis C

AIM

To evaluate interferon-λ3 (IFNL3) polymorphisms in response-guided pegylated interferon-α plus ribavirin (Peg-IFNα/RBV) therapy for genotype 2 (G2) chronic hepatitis C.

METHODS

Between January 2006 and June 2012, a total of 180 patients with chronic infections of G2 hepatitis C virus (HCV) were treated with response-guided Peg-IFNα/RBV therapy. The treatment duration was 24 wk for patients who achieved rapid virologic response (RVR), and 36 or 48 wk for patients who did not. Then, the impact of the IFNL3 single nucleotide polymorphism genotype (TT/non-TT at rs8099917) on treatment outcomes was evaluated in the 180 patients, and between patients infected with either HCV sub-genotype 2a or 2b.

RESULTS

Of the 180 patients evaluated, 111 achieved RVR, while the remaining 69 patients did not. In RVR patients, the sustained virologic response (SVR) rate was 96.4%, and the IFNL3 genotype did not influence the SVR rate (96.6% vs 95.8% in IFNL3 genotype TT vs non-TT). However, in non-RVR patients, the SVR rate decreased to 72.5% (P < 0.0001), and this rate was significantly different between the IFNL3 genotype TT and non-TT groups (80.0% vs 42.9%, P = 0.0146). Multivariate regression analysis in non-RVR patients identified the IFNL3 genotype TT as the only baseline-significant factor associated with SVR (OR = 5.39, 95%CI: 1.29-22.62; P = 0.0189). In analysis according to HCV sub-genotype, no significant difference in the SVR rate was found between HCV sub-genotypes 2a and 2b.

CONCLUSION

In response-guided Peg-IFNα/RBV combination therapy for chronically HCV G2-infected patients, the impact of the IFNL3 genotype on SVR was limited to non-RVR patients.

Interleukin-28B gene non-TT allele strongly predicts treatment failure for genotype 1 infected chronic hepatitis C patients with advanced fibrosis: a case control study

BACKGROUND

The role of single nucleotide polymorphisms (SNPs) of interleukin (IL)-28B in predicting therapeutic response of pegylated interferon (peg-IFN) plus ribavirin (PR) for genotype 1 infected chronic hepatitis C patients with advanced fibrosis (AF) is limited. The aim of this study is to assess its role in predicting sustained virologic responses (SVR) to treatment.

METHODS

Forty-two patients with biopsy proven hepatitis C virus (HCV) related AF (group A; Ishak fibrosis score, ≥4) and 126 sex- and HCV genotype-matched patients without AF (group B; Ishak fibrosis score, ≤3) were recruited into study. All patients received PR therapy for 24 weeks. Baseline and on-treatment clinical, virological and host factors were evaluated for treatment efficacy.

RESULTS

The SVR rate was significantly lower in group A than group B patients with genotype 1 infection (24% vs. 53.3%; p=0.011). However, it was similar in those with genotype non-1 infection (76.5% vs. 76.5%; p=1.0). IL-28B rs8099917 genotype TT is the strongest predictor for SVR in genotype 1 infection. Patients who had TT genotype and achieved RVR in group A had similar SVR rates with those in group B (44.4% vs. 53.3%; p=0.614). One third of patients in group A developed hematological adverse effects and had required modified doses during antiviral therapy.

CONCLUSIONS

In HCV genotype 1 infected AF receiving 24 weeks of PR treatment, patients with IL28B rs8099917 genotype TT, achieving RVR had similar SVR rate with those without AF. In contrast, patients with IL-28B rs8099917 non-TT genotype without achieving RVR are suggested to stop therapy.

Effect of prolonged administration of pegylated interferon/ribavirin therapy in genotypes 2a and 2b: propensity score-matched analysis

BACKGROUND AND AIM

Chronic hepatitis C genotype 2 patients show high susceptibility to pegylated interferon plus ribavirin therapy (PEG/RBV). However, the differences in response to therapy between genotypes 2a and 2b, and the efficacy of prolonged therapy for refractory patients have not been evaluated. We investigated the differences in response to PEG/RBV between each genotype and examined the efficacy of prolonged therapy.

METHODS

A total of 343 chronic hepatitis patients infected with hepatitis C virus (HCV) genotype 2 (2a: n = 195; 2b: n = 148) were enrolled in this study. All patients received PEG/RBV for 24 (24 week group, n = 242) or more weeks (prolonged group, n = 101). We analyzed the differences in virological response between genotypes 2a and 2b. Clinical and virological factors of patients in the 24-week group and the prolonged treatment group were matched using propensity score analysis, and the efficacy of prolonged therapy established by comparing time of serum HCV disappearance for each genotype.

RESULTS

Virological response tended to be higher for genotype 2a compared with genotype 2b; however, there was no significant difference in sustained virological response rates between genotypes (2a: 78.3%; 2b: 70.2%; P = 0.19). After propensity score matching, the adjusted P-value for sustained virological response rate was significantly different for genotype 2b patients with undetectable HCV-RNA between weeks 5 and 8, and for genotype 2a patients with detectable HCV-RNA at week 8.

CONCLUSION

Prolonged therapy with PEG/RBV may be effective when serum HCV-RNA is detectable at week 4 and week 8 for genotype 2b and 2a patients, respectively.

Association of interleukin 28B polymorphism and mutations in the NS5A region of hepatitis C virus genotype 2 with interferon responsiveness

BACKGROUND AND AIM

The single nucleotide polymorphism (SNP) of interleukin 28B (IL28B) and the mutations in the NS5A region of hepatitis C virus (HCV) genotype 1 have been associated with response to interferon (IFN) therapy. However, these relationships in patients with HCV genotype 2 are not well understood. The aim of this study was to investigate whether the SNP of IL28B (rs8099917) and amino acid substitutions in the NS5A region in patients with HCV genotype 2 affect the response to IFN and ribavirin combination therapy.

METHODS

The study enrolled 286 patients with chronic hepatitis C genotype 2. Patients received pegylated-IFN-alpha 2b once each week plus oral ribavirin daily for 24 weeks.

RESULTS

Of the 286 patients, 215 (75.2%) achieved sustained virologic response (SVR). Rate of SVR was similar in patients with IL28B TT allele (76%) and those with TG or GG alleles (72%). Patients with SVR were younger than those without SVR (P < 0.001). SVR was achieved in 65.9% of patients with wild-type IFN sensitivity-determining region (ISDR) and 83.5% of patients with mutant type (P < 0.001). There were no significant differences in other factors, including sex, alanine aminotransferase, platelet count, HCV viral load, HCV genotype, and IL28B genotype. The factors related to SVR on multivariate analysis were age (P = 0.019) and ISDR (P = 0.003).

CONCLUSIONS

ISDR sequence variations are significantly associated with IFN responsiveness in patients with HCV genotype 2. The SNP of IL28B was not associated with SVR in patients with HCV genotype 2.

Hepatitis C virus and interferon type III (interferon-λ3/interleukin-28B and interferon-λ4): genetic basis of susceptibility to infection and response to antiviral treatment

There has been a significant increase in our understanding of the host genetic determinants of susceptibility to viral infections in recent years. Recently, two single-nucleotide polymorphisms (SNPs), rs12979860 T/C and rs8099917 T/G, upstream of the interleukin (IL)-28B/interferon (IFN)-λ3 gene have been clearly associated with spontaneous and treatment-induced viral clearance in hepatitis C virus (HCV) infection. Because of their power in predicting the response to IFN/ribavirin therapy, the above SNPs have been used as a diagnostic tool, even though their relevance in the management of HCV infection will be blunt in the era of IFN-free regimens. The recent discovery of a new genetic variant, ss469415590 TT/ΔG, upstream of the IL-28B gene, which generates the novel IFN-λ4 protein, has opened up a new and alternative scenario to understand the functional architecture of type III IFN genomic regions and to improve our knowledge of the pathogenetic mechanism of HCV infection. A role of ss469415590 in predicting responsiveness to antiviral therapy has also been observed in HCV-infected patients receiving direct antiviral agents. The underlying biological mechanism that links the above IL-28B polymorphisms (in both IFN-λ3 and IFN-λ4) to spontaneous and treatment-induced clearance of HCV infection remains to be discovered. Despite this, shedding some light on this issue, which is the main aim of this review, may provide new insights into the general topic of 'host genetics and viral infections'.

Exploratory trial of ombitasvir and ABT-450/r with or without ribavirin for HCV genotype 1, 2, and 3 infection

OBJECTIVES

To examine the safety and efficacy of ombitasvir and ABT-450 with ritonavir (ABT-450/r) ± ribavirin (RBV) in treatment-naïve, non-cirrhotic adults with chronic HCV genotype 1-3 infection.

METHODS

Patients in this open-label, exploratory, phase 2, multicenter study received ombitasvir (25 mg QD) and ABT-450/r (200/100 mg QD) ± RBV for 12 weeks. Primary efficacy endpoint was HCV RNA < lower limit of quantitation (LLOQ) from week 4 through 12. Sustained virologic response 12 weeks post-treatment (SVR12) was a secondary endpoint.

RESULTS

Sixty-one patients were enrolled. Among genotype 1-, 2-, and 3-infected patients, respectively, HCV RNA was<LLOQ from week 4 through 12 in 10 (100%; 95% CI 69-100), 9 (90%; 56-100), and 7 (70%; 35-93) receiving the RBV-containing regimen and 9 (90%; 56-100), 8 (80%; 44-97), and 2 (18%; 2-52) receiving the RBV-free regimen. Among genotype 1-, 2-, and 3-infected patients, respectively, SVR12 was achieved by 10 (100%), 8 (80%), and 5 (50%) receiving the RBV-containing regimen, and 6 (60%), 6 (60%), and 1 (9%) receiving the RBV-free regimen. The most common adverse events were fatigue, nausea, and headache. One patient discontinued due to an adverse event.

CONCLUSIONS

In this study, ombitasvir and ABT-450/r ± RBV regimens were generally well-tolerated. Sustained virologic response was achieved in most patients with HCV genotype 1 or 2 infection, but low SVR rates were observed in HCV genotype 3-infected patients.

Interleukin 27 polymorphisms in HCV RNA positive patients: is there an impact on response to interferon therapy?

Background

Interleukin 27 (IL-27) has pleiotropic properties that can either limit or enhance immune responses. Recent studies revealed that single nucleotide polymorphisms (SNPs) of the IL-27 promoter region modulate the development of infectious diseases and individual's susceptibility to therapeutic response. Little is known about the relationship between IL-27 single nucleotide polymorphisms and therapy response in patients infected by hepatitis C virus (HCV). In this study we have investigated the potential role of SNPs in the promoter region of IL27 p28 gene (alleles rs153109) on the outcome of HCV infected patients.

Methods

rs153109, corresponding to position c.-964A>G of the IL-27 locus, was amplified from genomic DNA extracted from 15 patients with chronic hepatitis C stratified by sustained viral response (SVR), relapser and non-responder, after treatment with peginterferon-α (PegIFN- α) combined with ribavirin (RBV). Amplification products were studied by direct sequencing.

Results

This method has been applied in a preliminary study on patients with chronic hepatitis C to provide information for a standardized assay useful to genotyping of rs153109 SNPs of IL-27p28. The genotype distribution of the c.-964 A>G polymorphism was more present in patients who did not achieve a SVR. By contrast, the genotype G/G was absent in non-responder and relapser patients. Moreover, the analysis of allelic distribution of rs153109 highlighted a predominance of allele A in all genotypes in spite of allele G.

Conclusions

Our work provides preliminary information for a standardized method potentially useful for genotyping rs153109, and suggests its utility as a candidate approach to evaluate IL-27 p28 polymorphisms as additional clinical predictors of response to therapies in HCV infected patients.

Interleukin 28B polymorphism predicts interferon plus ribavirin treatment outcome in patients with hepatitis C virus-related liver cirrhosis: A multicenter retrospective study in Japan

AIM

This study evaluated the efficacy of interferon plus ribavirin and examined whether interleukin 28B (IL28B) polymorphism influenced treatment outcome in Japanese patients with hepatitis C virus (HCV)-related liver cirrhosis (LC).

METHODS

Fourteen collaborating centers provided details of 261 patients with HCV-related LC undergoing treatment with interferon plus ribavirin. Univariate and multivariate analyses were used to establish which factors predicted treatment outcome.

RESULTS

Eighty-four patients (32.2%) achieved a sustained virological response (SVR). SVR rates were 21.6% (41/190) in patients with HCV genotype 1 with high viral load (G1H) and 60.6% (43/71) in patients with non-G1H. In patients with non-G1H, treatment outcome was effective irrespective of IL28B polymorphism. In those with G1H, SVR was achieved in 27.1% of patients with the IL28B rs8099917 TT allele compared with 8.8% of those with the TG/GG alleles (P = 0.004). In patients with G1H having TT allele, treatments longer than 48 weeks achieved significantly higher SVR rates than treatments less than 48 weeks (34.6% vs 16.4%, P = 0.042). In patients with G1H having TG/GG alleles, treatments longer than 72 weeks achieved significantly higher SVR rates than treatments less than 72 weeks (37.5% vs 4.1%, P = 0.010).

CONCLUSION

Interferon plus ribavirin treatment in Japanese patients with non-G1H HCV-related LC was more effective than those with G1H and not influenced by IL28B polymorphism. In those with G1H, IL28B polymorphism may predict SVR and guide treatment duration: SVR rates were higher in those with the TT allele treated for more than 48 weeks and those with the TG/GG alleles treated for more than 72 weeks.

IFNL3 polymorphisms predict response to therapy in chronic hepatitis C genotype 2/3 infection

BACKGROUND & AIMS

Single nucleotide polymorphisms (SNPs) near the interferon lambda 3 (IFNL3, previously known as IL28B) region are the strongest baseline predictors of sustained virologic response (SVR) to pegylated interferon and ribavirin therapy in hepatitis C virus (HCV) genotype 1 infection. Whether IFNL3 SNPs influence treatment response in genotype 2 and 3 (HCV-2/3) infection remains controversial. This study sought to clarify in a large cohort, whether SNPs in the IFNL3 region are associated with treatment response in HCV-2/3 patients.

METHODS

The cohort comprised 1002 HCV-2/3 Caucasians patients treated with pegylated interferon-alpha and ribavirin who underwent genotyping for the SNPs rs12979860 and rs8099917.

RESULTS

Overall, 736 (73.5%) patients achieved SVR (81.9%, 67.9%, and 57.8% for rs12979860 CC, CT, and TT [p = 0.0001]; 78%, 68.7%, and 46.3% for rs8099917 TT, TG, and GG [p = 0.0001]). By logistic regression, both rs12979860 CC and rs8099917 TT were independent predictors of SVR with an odds ratio (OR) of 2.39 (1.19-3.81) p = 0.0001 and OR 1.85 (1.15-2.23) p = 0.0001, respectively. IFNL3 responder genotypes were more frequent in relapsers than null-responders (p = 0.0001 for both SNPs). On-treatment rapid virological response (RVR) was predictive of SVR only in those individuals with IFNL3 non-responder genotypes (rs12979860 CT/TT and rs8099917 TG/GG).

CONCLUSIONS

This adequately powered study in patients with HCV genotypes 2 or 3 infection clearly demonstrates that IFNL3 genotypes are the strongest baseline predictor of SVR, in keeping with the known association for genotype 1 infection. IFNL3 genotyping can aid in therapeutic decision making for these patients.

Pharmacogenetics of hepatitis C: transition from interferon-based therapies to direct-acting antiviral agents

Hepatitis C virus (HCV) has emerged as a major viral pandemic over the past two decades, infecting 170 million individuals, which equates to approximately 3% of the world’s population. The prevalence of HCV varies according to geographic region, being highest in developing countries such as Egypt. HCV has a high tendency to induce chronic progressive liver damage in the form of hepatic fibrosis, cirrhosis, or liver cancer. To date, there is no vaccine against HCV infection. Combination therapy comprising PEGylated interferon-alpha and ribavirin has been the standard of care for patients with chronic hepatitis C for more than a decade. However, many patients still do not respond to therapy or develop adverse events. Recently, direct antiviral agents such as protease inhibitors, polymerase inhibitors, or NS5A inhibitors have been used to augment PEGylated interferon and ribavirin, resulting in better efficacy, better tolerance, and a shorter treatment duration. However, most clinical trials have focused on assessing the efficacy and safety of direct antiviral agents in patients with genotype 1, and the response of other HCV genotypes has not been elucidated. Moreover, the prohibitive costs of such triple therapies will limit their use in patients in developing countries where most of the HCV infection exists. Understanding the host and viral factors associated with viral clearance is necessary for individualizing therapy to maximize sustained virologic response rates, prevent progression to liver disease, and increase the overall benefits of therapy with respect to its costs. Genome wide studies have shown significant associations between a set of polymorphisms in the region of the interleukin-28B (IL28B) gene and natural clearance of HCV infection or after PEGylated interferon-alpha and ribavirin treatment with and without direct antiviral agents. This paper synthesizes the recent advances in the pharmacogenetics of HCV infection in the era of triple therapies.

IFNL4/IL-28B haplotype structure and its impact on susceptibility to hepatitis C virus and treatment response in the Japanese population

A new type III interferon, IFN lambda 4 (IFNL4), and its single-nucleotide polymorphism (SNP) ss469415590 causing a frame shift have been recently reported strongly to affect antiviral therapy for chronic hepatitis C virus (HCV) infection in African and Caucasian populations compared to previously reported IL-28B SNPs rs12979860 and rs8099917. To compare the predictability for treatment outcome among those polymorphisms, we estimated haplotype structure of IFNL4/IL-28B consisting of the three SNPs in 4630 Japanese chronic hepatitis C patients and 1122 healthy controls and then compared their impact on response to pegylated-IFN (PEG-IFN) plus ribavirin (RBV) combined therapy in 903 HCV-1b-infected patients. A total of five haplotypes were identified, although two major haplotypes accounted for >99 % of the variation. The SNPs were tightly linked but not in absolute linkage disequilibrium. We could not find any difference in the predictive impact of any of these three SNPs with regard to susceptibility to HCV and treatment response. However, patients with favourable rs8099917 TT, linked to unfavourable genotypes of ss469415590 and rs12979860, showed poor initial viral response compared with those with all favourable genotypes (P = 0.0022). These findings suggest that, in part, ss469415590 and rs12979860 may have better predictive impact on response to PEG-IFN plus RBV therapy in the Japanese population, especially in patients with any of the minor haplotypes consisting of these SNPs.

Individualization of chronic hepatitis C treatment according to the host characteristics

Hepatitis C virus (HCV) infection is a global health problem that affects more than 170 million people worldwide. It is a major cause of cirrhosis and hepatocellular carcinoma, making the virus the most common cause of liver failure and transplantation. The standard-of-care treatment for chronic hepatitis C (CHC) has been changed during the last decade and direct acting antiviral drugs have already been used. Besides, understanding of the pathogenesis of CHC has evolved rapidly during the last years and now several host factors are known to affect the natural history and response to treatment. Recent genome-wide association studies have shown the important role of interleukin-28B and inosine triphosphatase in HCV infection. The present review article attempts to summarize the current knowledge on the role of host factors towards individualization of HCV treatment.

The role of pharmacogenetics in the treatment of chronic hepatitis C infection

Hepatitis C virus (HCV) chronically infects 170 million people worldwide. Until recently, combination therapy with peginterferon-α (pegIFN) and ribavirin (RBV) has been the standard of care. However, for many patients, especially those infected with the most common HCV genotype 1 (HCV-1), this treatment has resulted in unsatisfactory treatment response rates. Many clinical factors, including pharmacogenetics, influence the treatment response rate. Genetic variation in the interleukin 28B (IL28B) gene is the major determinant of treatment response, a finding that has been replicated in multiple independent cohorts. This review focuses on the association between pharmacogenetics and conventional pegIFN/RBV therapy in patients infected with HCV non-genotype 1; patients reinfected with HCV after liver transplantation; and patients coinfected with HCV and human immunodeficiency virus. We also review the pharmacogenetic data for boceprevir and telaprevir triple therapy in patients with HCV-1 infection, as well as viral genomic polymorphisms and genetic variants that may protect against anemia. Pharmacogenetic information offers a personalized medicine approach to help clinicians and patients make better informed decisions to maximize response and minimize toxicity for the treatment of chronic HCV infection.

Prediction of efficacy to pegylated interferon-α-2b plus ribavirin in patients with genotype 2 hepatitis C virus using viral response within 2 weeks

AIM

Rapid virological response (RVR), defined as serum hepatitis C virus (HCV) RNA negativity at 4 weeks, is the most useful predictor of sustained virological response (SVR) to standard pegylated interferon (PEG IFN) plus ribavirin therapy for patients infected with genotype 2 HCV. The aim of the present study was to predict SVR using viral response within 2 weeks of therapy initiation.

METHODS

Of 64 HCV genotype 2 patients with a high viral load treated with standard PEG IFN-α-2b plus weight-based ribavirin for 24 weeks, 58 patients whose adherence was more than 67% were analyzed. RNA and core antigen levels were measured at four time points: the day of therapy initiation, the following day, and at 1 and 2 weeks.

RESULTS

SVR was achieved in 73% (47/64) of patients. Univariate analysis of SVR contributing factors showed significant differences with age, bodyweight, white blood cell count, platelet count, fibrosis marker levels, baseline core antigen level and viral response. The area under the receiver-operator curve (AUC) of the core antigen level at 1 week (AUC, 0.940) was the highest among the significant SVR predicting factors. Setting 100 fmol/L as the cut-off value for core antigen level at 1 week, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy for predicting SVR were 100%, 86%, 96%, 100% and 97%, respectively, and for predicting RVR were 66%, 93%, 97%, 46% and 72%, respectively.

CONCLUSION

The HCV core antigen level at 1 week after therapy initiation is the most useful predictor for SVR.

Role of interleukin-28B genetic polymorphisms in Korean patients with hepatitis C virus infection

BACKGROUND/AIMS

This study investigated the role of single nucleotide polymorphisms (SNPs) near the interleukin-28B (IL28B) gene with respect to clinical outcomes and the antiviral response in hepatitis C virus (HCV) infection to suggest the practical utility of IL28B genotyping in Korea.

METHODS

Two SNPs near IL28B, rs12979860 and rs8099917, were analyzed using an allelic discrimination assay in a total of 454 individuals, including 147 health-check examinees and 307 patients with HCV infection.

RESULTS

The CC genotype frequency was significantly higher in the spontaneous recovery group than in the chronic infection group and was higher in the chronic hepatitis group than in the liver cirrhosis or hepatocellular carcinoma group, suggesting its favorable role in the clinical outcome. Multivariate analysis revealed that the rs12979860 CC genotype was an independent predictor of sustained virologic response (SVR) in genotype 1 HCV infection. During the currently used response-guided therapy, IL28B genotyping was most helpful for the patients who exhibit early virologic responses without rapid virologic responses, as those patients exhibiting the non-CC type did not achieve SVR, although they represented approximately one-third of the total patients.

CONCLUSIONS

The IL28B SNP is an independent predictor of SVR. Our results may be helpful if the findings are carefully applied to select patients in Korea.

HLA-DQB1*03 confers susceptibility to chronic hepatitis C in Japanese: a genome-wide association study

Hepatitis C virus (HCV) establishes a chronic infection in 70-80% of infected individuals. Many researchers have examined the effect of human leukocyte antigen (HLA) on viral persistence because of its critical role in the immune response against exposure to HCV, but almost all studies have proven to be inconclusive. To identify genetic risk factors for chronic HCV infection, we analyzed 458,207 single nucleotide polymorphisms (SNPs) in 481 chronic HCV patients and 2,963 controls in a Japanese cohort. Next, we performed a replication study with an independent panel of 4,358 cases and 1,114 controls. We further confirmed the association in 1,379 cases and 25,817 controls. In the GWAS phase, we found 17 SNPs that showed suggestive association (P < 1 × 10^-5). After the first replication study, we found one intronic SNP in the HLA-DQ locus associated with chronic HCV infection, and when we combined the two studies, the association reached the level of genome-wide significance. In the second replication study, we again confirmed the association (P_combined = 3.59 × 10⁻¹⁶, odds ratio [OR] = 0.79). Subsequent analysis revealed another SNP, rs1130380, with a stronger association (OR=0.72). This nucleotide substitution causes an amino acid substitution (R55P) in the HLA-DQB1 protein specific to the DQB1*03 allele, which is common worldwide. In addition, we confirmed an association with the previously reported IFNL3-IFNL4 locus and propose that the effect of DQB1*03 on HCV persistence might be affected by the IFNL4 polymorphism. Our findings suggest that a common amino acid substitution in HLA-DQB1 affects susceptibility to chronic infection with HCV in the Japanese population and may not be independent of the IFNL4 genotype.

Prediction of response to pegylated interferon/ribavirin combination therapy for chronic hepatitis C genotypes 2a and 2b and high viral load

OBJECTIVE

We investigated the impact of host genetics represented by the single nucleotide polymorphism (SNP) of the IL28B gene and viral genetic variations within the nonstructural protein 5A (NS5A) [including the interferon (IFN)/ribavirin (RBV) resistance-determining region (IRRDR) and the IFN sensitivity-determining region (ISDR)] on the outcome of pegylated IFN and RBV (PEG-IFN/RBV) treatment.

METHODS

Sixty-six patients infected with hepatitis C virus (HCV)-2a or HCV-2b who received PEG-IFN/RBV for 24 weeks were examined.

RESULTS

In HCV-2a, the major genotype of IL28B SNP showed a tendency toward association with sustained virological response (SVR) and rapid virological response (RVR), and four or more mutations in IRRDR (IRRDR[2a] ≥4) and one or more mutations in ISDR plus its carboxyl-flanking region (ISDR/+C[2a] ≥1) were significantly associated with SVR and RVR. In HCV-2b, one or more mutations in the N-terminal part of IRRDR (IRRDR/N[2b] ≥1) were significantly associated with RVR. Multivariate analysis identified the major genotype of IL28B SNP and IRRDR[2a] ≥4 as independent predictive factors of SVR in HCV-2a, with IRRDR[2a] ≥4 being more powerful than the IL28B SNP. Also, IRRDR[2a] ≥4 in HCV-2a and IRRDR/N[2b] ≥1 in HCV-2b were significant determiners of RVR.

CONCLUSION

The NS5A sequence heterogeneity and IL28B SNP are useful factors to predict the sensitivity to PEG-IFN/RBV therapy in HCV-2a and HCV-2b infections.

New proposal for response-guided peg-interferon-plus-ribavirin combination therapy for chronic hepatitis C virus genotype 2 infection

This study aimed to determine the most suitable duration of pegylated-interferon (Peg-IFN)-plus-ribavirin combination therapy in patients infected with hepatitis C virus (HCV) genotype 2 who had not achieved rapid virological response (serum HCV RNA disappearance after 4 weeks of therapy). HCV genotype 2 patients (n = 182) with a high viral load received >80% of the standard Peg-IFN-plus-ribavirin dose for at least 24 weeks, and their final virological responses were studied. Patients were classified into "rapid virological response" and "non-rapid virological response" groups. The non-rapid virological response group was further divided into a "virological response at 8 weeks" (serum HCV RNA disappearance after 8 weeks of therapy) and a "non-virological response at 8 weeks" group. Factors related to rapid virological response and optimal therapy duration in the non-rapid virological response group were evaluated. Multivariate logistic regression analysis showed that subtype HCV genotype 2a (P = 0.0015) and low concentration of pretreatment serum HCV RNA (P = 0.0058) were independent factors in a rapid virological response. In the virological response at 8 weeks group, the sustained virological response rate after 24 weeks of therapy was significantly lower than after 36 weeks (P = 0.044) or after 48 weeks (P = 0.006), and was similar for 36- and 48-weeks. The cost for achieving (CAS) one sustained virological response was lowest with 36-week therapy. Prolongation of Peg-IFN-plus-ribavirin combination therapy to 36 weeks is suitable for achieving virological response at 8 weeks, given the high, sustained virological response rate and cost benefit.

Effects of IL-28B gene polymorphism on response to peginterferon plus ribavirin combination therapy for genotype 2 chronic hepatitis C

AIM

Interleukin (IL)-28B gene polymorphism is closely linked with treatment response to peginterferon plus ribavirin combination therapy for hepatitis C virus genotype 1. However, few studies have reported its effects on therapy for genotype 2. We aimed to examine the effects of IL-28B gene polymorphism on treatment response in hepatitis C virus genotype 2 patients.

METHODS

In a retrospective study of 101 patients infected with either genotype 2a (n = 65) or 2b (n = 36) and treated with peginterferon plus ribavirin, we investigated predictive factors for a sustained virological response (SVR), including genetic variations near the IL-28B gene (rs8099917, rs11881222 and rs8103142) and clinical variables such as age, sex, body mass index, stage of fibrosis and drug adherence.

RESULTS

Ultra-rapid virological response, rapid virological response (RVR), end-of-treatment response, SVR and relapse rates were 22.2%, 61.4%, 95.0%, 87.1% and 7.9%, respectively. In univariate analysis, RVR and IL-28B single nucleotide polymorphisms (SNP) (rs8099917, rs11881222 and rs8103142) were significantly associated with SVR. In subgroup analysis, IL-28B SNP were significantly associated with SVR in genotype 2a patients but not in genotype 2b patients. In multiple logistic regression analysis, RVR and IL-28B SNP (rs8099917) were independently associated with SVR. Furthermore, IL-28B SNP was significantly associated with relapse but RVR was not.

CONCLUSION

In genotype 2 patients treated with peginterferon plus ribavirin combination therapy, IL-28B gene polymorphism was a significant independent predictor of SVR as well as RVR. IL-28B major allele may favor reduced relapse rates in patients with genotype 2 chronic hepatitis C.

Polymorphism Near the Interleukin-28B Gene and Anti-Hepatitis C Viral Response

In a recent genome-wide association study, single nucleotide polymorphisms (SNPs) located near the interleukin-28B gene (IL28B), which encodes type III interferon (IFN) λ3, were shown to be strongly associated with a viral response to pegylated IFNα (PEG-IFNα) and ribavirin (RBV) combination therapy and spontaneous viral clearance in patients chronically and acutely infected with hepatitis C virus (HCV), respectively. The global distribution of allele frequencies shows a remarkable pattern, in which a favorable allele is nearly fixed in East Asia, has an intermediate frequency in Europe, and is least frequent in Africa. Although the underlying mechanisms responsible for viral responses associated with IL28B SNPs have not been completely elucidated, IFN-stimulated gene expression in patients with unfavorable IL28B genotypes tends to be high at baseline and is insufficiently induced by exogenous IFN administration, resulting in poor treatment outcomes. Clinically, triple therapy with PEG-IFNα/RBV together with direct-acting antiviral agents (DAAs) is currently used to treat chronic hepatitis C as a first-line therapy. Although the predictive power of IL28B status may be attenuated, the IL28B genotype will remain relevant to the outcomes of DAA therapy when used in combination with PEG-IFNα as a backbone. Even with the introduction of IFN-free therapies with a new class of highly effective DAAs, IL28B SNPs are still useful predictors of treatment outcomes and can be used to individualize treatment strategies to maximize cost-effectiveness and identify patients at risk of being refractory to treatment. This review summarizes the current understanding of the clinical significance and role of IL28B in HCV infection and response to therapy.

IL-28B polymorphisms and the response to antiviral therapy in HCV genotype 2 and 3 varies by ethnicity: a meta-analysis

Studies of IL-28B genotype in patients with hepatitis C virus (HCV) genotype 2/3 infection have yielded conflicting results. The aim of this meta-analysis was to obtain a pooled odds ratio (OR) of the impact of IL-28B genotype on achieving sustained virologic response (SVR) in patients with HCV genotype 2/3 infection treated with pegIFN and ribavirin. A meta-analysis with a random effects model was performed, and study heterogeneity and publication bias were assessed. Forty-three percent of the Caucasians (11 studies) and 86% of Asians (five studies) had the favourable IL-28B genotype. In Caucasians, the pooled OR of SVR with the favourable IL-28B genotype was 1.36 (95%CI: 0.98-1.88, P = 0.07) in all patients and 1.55 (95%CI: 1.10-2.18, P = 0.01) in patients treated with pegIFN and ribavirin for ≥24 weeks. In Asians, the pooled OR of SVR in patients with the favourable IL-28B genotype was 1.99 (95%CI: 0.94-4.25, P = 0.07). The favourable IL-28B genotype was also significantly associated with rapid virologic response (RVR) in both groups (Caucasians: OR: 1.82, 95%CI: 1.12-2.96, P = 0.02; Asians: 2.39, 95%CI: 1.39-4.11, P = 0.002), as well as the likelihood of an SVR in a subgroup of 350 Caucasian patients without an RVR (OR: 3.29, 95%CI: 1.67-6.51, P = 0.001). The favourable IL-28B genotype is a statistically significant predictor of SVR and RVR in Caucasian patients treated with pegIFN and ribavirin for 24 weeks. In contrast, the favourable IL-28B genotype is associated with RVR, but not SVR in Asian HCV genotype 2 patients.

Association between an IL-28B genetic polymorphism and the efficacy of the response-guided pegylated interferon therapy in children with chronic hepatic C infection

AIM

The relation between interleukin-28B (IL-28B) genotypes and treatment-induced hepatitis C virus (HCV) clearance in children is unknown. This was a retrospective study to evaluate the association between an IL-28B genotype (rs8099917) and pegylated (PEG) interferon (IFN) response.

METHODS

Sixty-three children (median age, 7 years; range, 3-17 years; 22 with HCV genotype 1 and 41 with genotype non-1) with chronic HCV infection who were treated with response-guided PEG IFN on the basis of viral load were evaluated.

RESULTS

The duration of treatment with PEG IFN was 24 weeks in one child (2%), 36 weeks in eight children (13%), 48 weeks in 36 children (57%), 60 weeks in 11 children (17%) and 72 weeks in seven children (11%). Of the total 63 children, 54 (86%) were initially treated with PEG IFN-α-2a monotherapy. The remaining nine (14%) received PEG IFN plus ribavirin as the initial therapy. Of the 54 children initially treated with monotherapy, 35 (65%) continued receiving monotherapy until the end of treatment. In the remaining 19 (35%), monotherapy was changed to PEG IFN plus ribavirin at 12 or 24 weeks of treatment. Of the total 63 children, 54 (86%) achieved a sustained virological response (SVR). In univariate analysis, rs8099917 genotype TT (P = 0.075) showed a weak association with SVR. However, the multivariate analysis revealed no predictive factors which had a significant association with SVR.

CONCLUSION

The IL-28B genotype was not a strong pretreatment predictor for SVR in a mixed genotype cohort of children treated with response-guided PEG IFN therapy.

Value of IL28B genotyping in patients with HCV-related mixed cryoglobulinemia: results of a large, prospective study

HCV-related mixed cryoglobulinemia (MC) is characterized by clonal expansion of B cells producing a polyreactive natural antibody (rheumatoid factor) and interferon (IFN)-based therapy is the first therapeutic option in mild-moderate MC. Single nucleotide polymorphisms (SNPs) proximal to genes involved in the innate response (IL28B/IFN-λ gene family) are strongly associated with spontaneous and IFN-induced viral clearance in hepatitis C, but no data exist about their role in HCV-positive MC. A large cohort of patients with HCV and MC was studied to evaluate the influence of IL28B genotype on the response to treatment and/or the evolution to MC of HCV infection. The rs12979860/rs8099917 IL28B polymorphisms were analysed in 481 consecutive HCV-positive subjects (250 with MC and 231 without MC, as controls) using real-time PCR and direct sequencing. Hundred and fifteen HCV patients with MC received standard anti-HCV therapy, and the results were evaluated according to the IL28B SNP distribution. Similar IL28B SNPs allele frequencies were recorded for patients and controls. IL28B major allele homozygosis (for both SNPs tested) was tightly correlated with virological and clinical response (P = 0.002). A statistically significant association was limited to 'difficult-to-treat' (G1/4) HCV genotypes. The IL28B genotype was a strong independent predictor of response (P = 0.007, OR 6.06; CI 1.65-22.22). The IL28B genotype was confirmed to be a useful predictor of response to IFN-based therapy in patients with HCV and MC. The very close correlation between IL28B SNP distribution, virological and clinical response definitively confirmed the key role played by HCV in MC. Conversely, the IL28B genotype does not seem to influence the evolution to MC.

IL28B polymorphisms as a pretreatment predictor of response to HCV treatment

Genome-wide association studies have identified polymorphisms located near the gene encoding IL28B, which turned out to be the best predictor of response to pegylated interferon plus ribavirin for chronic hepatitis C virus (HCV) genotype 1 infection. This association was extended to spontaneous clearance of HCV, suggesting shared mechanisms of treatment and natural control of this virus. In addition to the biologic implications for innate immunity and HCV, a variety of clinical studies have suggested possible translation to a useful genetic test for practitioners. This article reviews the discovery, biology, and potential clinical applications that have stemmed from the seminal observation that IL28B polymorphisms are a main predictor of HCV clearance.

Allele-specific PCR for determination of IL28B genotype

The IL28B genotype is a critical determinant of interferon response in patients infected with hepatitis C virus genotype 1. We describe an allele-specific PCR assay for the IL28B genotype. The assay is simple and robust, uses commonly available real-time PCR instrumentation, and is well suited for clinical laboratories offering IL28B genotyping.

Host genetic variants in the pathogenesis of hepatitis C

Direct-acting antiviral drugs (DAAs) are currently replacing antiviral therapy for Hepatitis C infection. Treatment related side effects are even worse and the emergence of resistant viruses must be avoided because of the direct-antiviral action. Altogether it remains a challenge to take treatment decisions in a clinical setting with cost restrictions. Genetic host factors are hereby essential to implement an individualized treatment concept. In recent years results on different genetic variants have been published with a strong association with therapy response, fibrosis and treatment-related side effects. Polymorphisms of the IL28B gene were identified as accurate predictors for therapy response and spontaneous clearance of HCV infection and are already used for diagnostic decisions. For RBV-induced side effects, such as hemolytic anemia, associations to genetic variants of inosine triphosphatase (ITPA) were described and different SLC28 transporters for RBV-uptake have been successfully analyzed. Fibrosis progression has been associated with variants of Vitamin D receptor (VDR) and ABCB11 (bile salt export pump). Cirrhotic patients especially have a high treatment risk and low therapy response, so that personalized antiviral treatment is mandatory. This review focuses on different host genetic variants in the pathogenesis of Hepatitis C at the beginning of a new area of treatment.

Novel biosensor-based microarray assay for detecting rs8099917 and rs12979860 genotypes

AIM

To evaluate a novel biosensor-based microarray (BBM) assay for detecting rs12979860 and rs8099917 genotypes.

METHODS

Four probes specific for rs8099917C/T or rs12979860G/T detection and three sets of quality control probes were designed, constructed and arrayed on an optical biosensor to develop a microarray assay. Two sets of primers were used in a one tube polymerase chain reaction (PCR) system to amplify two target fragments simultaneously. The biosensor microarray contained probes that had been sequenced to confirm that they included the rs8099917C/T or rs12979860G/T alleles of interest and could serve as the specific assay standards. In addition to rehybridization of four probes of known sequence, a total of 40 clinical samples collected from hepatitis C seropositive patients were also tested. The target fragments of all 40 samples were amplified in a 50 μL PCR system. Ten μL of each amplicon was tested by BBM assay, and another 40 μL was used for sequencing. The agreement of the results obtained by the two methods was tested statistically using the kappa coefficient. The sensitivity of the BBM assay was evaluated using serial dilutions of ten clinical blood samples containing 10(3)-10(4) white cells/μL.

RESULTS

As shown by polyacrylamide gel electrophoresis, two target segments of the interleukin 28B-associated polymorphisms (SNPs) were successfully amplified in the one-tube PCR system. The lengths of the two amplified fragments were consistent with the known length of the target sequences, 137 and 159 bps. After hybridization of the PCR amplicons with the probes located on the BBM array, the signals of each allele of both the rs8099917 SNPs and rs12979860 SNPs were observed simultaneously and were clearly visible by the unaided eye. The signals were distinct from each other, could be interpreted visually, and accurately recorded using an ordinary digital camera. To evaluate the specificity of the assay, both the plasmids and clinical samples were applied to the microarray. First, 30 PCR amplicons of the various SNP alleles were hybridized on the BBM microarray. Full agreement between plasmids and the BBM assay was observed, with 30/30 correct matches (100%). The kappa value for the BBM assay with plasmids was 1.00 (P < 0.05). For the 40 clinical blood samples, the BBM assay hybridization and direct sequencing results were compared for each amplicon. For patient blood samples, agreement was 28/28 for rs8099917T/T, 9/11 for rs8099917T/G, 1/1 for rs8099917G/G, 24/24 for rs12979860C/C, 11/14 for rs12979860C/T, and 2/2 for rs12979860T/T. Only five clinical samples of amplicon assay and direct sequencing results were discordant and heterozygotes: 2/11 rs8099917T/G and 3/14 rs12979860C/T. The agreement of outcomes between BBM assay and direct sequencing for the detection of rs8099917 and rs12979860 was 95% and 92.5%, respectively; and the corresponding kappa values were 0.88 and 0.85 (A kappa value > 0.75 was defined as substantial agreement). The BBM assay and sequencing had similar specificities for detection and identification of the two SNPs and their alleles. The sensitivity evaluation showed that the BBM assay could detect and identify SNP sequences present in blood samples containing as few as 10(2) white blood cells/μL.

CONCLUSION

This biosensor microarray assay was highly specific, sensitive, rapid and easy to perform. It is compatible with clinical practice for detection of rs8099917 and rs12979860.

None of the six SNPs of IL28B could predict treatment responses in genotype 2 chronic HCV infected patients by propensity score matching analysis

BACKGROUND & AIMS

A combination of pegylated interferon-alpha and ribavirin (PR) is the standard therapy for patients with chronic hepatitis C. The impact of polymorphism of interleukin-28B (IL28B) on sustained virological response (SVR) to PR has been well documented in patients with CHC genotype-1 (GT1), but it is controversial in genotype-2 (GT2) CHC patients. This study investigated the predictability of six single nucleotide polymorphisms (SNP) of IL28B on the treatment responses of PR in patients with CHC GT2.

METHOD

197 CHC GT2 consecutive patients who received PR treatment in our prospective cohort were enrolled. Hepatitis C virus (HCV) genotyping, quantification of HCV-RNA and genotyping of the ten SNPs of IL28B were performed. Six SNPs of IL28B were chosen for analysis. The propensity score matching (PSM) analysis was applied using patients with CHC GT1 in another prospective cohort as a positive comparison to avoid covariate bias.

RESULTS

The distribution of the six SNPs was similar in GT1 and GT2 patients. Five of these SNPs had strong association with treatment responses in GT1 but not in GT2 patients. After PSM analysis, these five SNPs still showed strong association with rapid virological response (RVR), cEVR and SVR in GT1 and had no influence in GT2 patients. Furthermore, rs12979860 and baseline viral load were the predictors for both RVR and SVR in GT1 patients. However, only baseline viral load could predict RVR and SVR in GT2 patients. In addition, in patients without RVR, rs12979860 was the only predictor for SVR in GT1 but no predictor for SVR was found in GT2.

CONCLUSIONS

The genetic polymorphisms of IL28B had no impact on treatment responses in GT2 patients.

Interleukin-28B polymorphisms on the SVR in the treatment of naïve chronic hepatitis C with pegylated interferon-α plus ribavirin: a meta-analysis

There are accurate but inconclusive data on the association between single nucleotide polymorphisms (SNPs) of interleukin (IL)-28B and sustained virological response (SVR) in chronic hepatitis C (CHC). This meta-analysis aimed to derive a more precise estimation of the effects of IL-28B SNPs locus (rs12979860 and rs8099917) on SVR in naïve CHC patients receiving pegylated interferon alpha (PEG-IFN-α) plus ribavirin. Literature search was conducted up to June, 2011, in PubMed, EMBASE and Cochrane Database of Systematic Reviews. A total of 36 studies involving 10912 cases with CHC receiving PEG-IFN-α plus ribavirin met the inclusion criteria. Analyses were stratified either by ethnicity or genotype of hepatitis C virus. In genotype 1/4 patients, rs12979860 CC was associated with high SVR in CHC patients (Caucasian: odds ratio (OR), 4.567; 95% confidence interval (CI), 3.826-5.452; Asian: OR, 4.033; 95%CI, 3.050-5.333; African American: OR, 4.297; 95%CI, 2.168-8.515; Hispanics: OR, 4.350; 95%CI, 2.817-6.717) but had no effect in genotype 2/3. In Caucasian (genotype 1/4: OR, 2.542; 95%CI, 2.108-3.065; genotype 2/3: OR, 1.363; 95%CI, 1.020-1.820) and Asian (genotype 1/4: OR, 5.214; 95%CI, 3.694-7.360; genotype 2/3: OR, 1.785; 95%CI, 1.095-2.910), rs8099917 TT was associated with high SVR in both genotype 1/4 and 2/3. Meta-regression showed that in Caucasians with CHC genotype 1/4, gender male might contribute to the effect of rs12979860 on SVR but advanced fibrosis might weaken this effect. Furthermore, in Asians with CHC genotype 1/4, high baseline viral load and advanced fibrosis might also undermine the effect of rs8099917 on SVR. This meta-analysis suggested that IL-28B rs12979860 CC and rs8099917 TT were associated with high SVR rate in CHC genotype 1/4. In CHC genotype 2/3, rs8099917 TT carriers also had higher SVR.

Association of IL28B genotype and viral response of hepatitis C virus genotype 2 to interferon plus ribavirin combination therapy

The impacts of IL28B genotype to treatment response of hepatitis C virus (HCV) genotype 2 are still not clear. A total of 381 consecutive Japanese patients infected with HCV genotype 2, who could complete combination therapy with interferon (IFN) plus ribavirin for 24 weeks, were evaluated to investigate pretreatment predictors. Patients, who could not achieve sustained virological response at the first course of 24-week IFN plus ribavirin, were recruited into the study protocol of total 48-week IFN plus ribavirin. In 24-week regimen, rates of sustained virological response and rapid virological response were 82% and 50%, respectively. There were no significant differences in rates of sustained virological response and rapid virological response, according to IL28B genotype. Multivariate analysis identified younger age, higher level of albumin, absence of past history of IFN, and lower level of viremia as significant determinants of sustained virological response. As significant or marginal significant determinants of non-sustained virological response regardless of rapid virological response, multivariate analysis identified IL28B rs8099917 genotype TG + GG and lower level of albumin. In 48-week regimen to 10 patients of non-sustained virological response at the first course of 24-week regimen, sustained virological response rates were 70%. All of six patients, with IL28B TT and relapse at the first course of 24-week regimen, could achieve sustained virological response, but two patients with IL28B TG could not achieve sustained virological response. In conclusion, the present results suggest that IL28B genotype might partly affect viral response of HCV genotype 2 to combination therapy.

Does IL28B genotyping still have a role in the era of direct-acting antiviral therapy for chronic hepatitis C infection?

IL28B genotype has been shown to be the strongest pretreatment predictor of sustained virological response (SVR) in patients with genotype 1 chronic hepatitis C infection (CHC) treated with pegylated interferon (peg-IFN) and ribavirin (RBV). Patients carrying the good response genotype have a two- to threefold higher chance of SVR than those with a poor response genotype, manifest as dramatically improved early viral kinetics. However, the treatment paradigm for CHC is changing with the introduction of potent direct-acting antivirals (DAAs). IL28B genotype remains relevant to both telaprevir and boceprevir treatment regimens, although the strength of association with virological response is attenuated. The association between IL28B genotype and outcomes of treatment regimens that involve peg-IFN plus combination DAA therapy, or IFN-free regimens, is currently being evaluated. IL28B genotype may remain relevant to individualizing the choice of treatment regimen in the future.

Test of IL28B polymorphisms in chronic hepatitis C patients treated with PegIFN and ribavirin depends on HCV genotypes: results from a meta-analysis

BACKGROUND

Many studies have been published on the association between single nucleotide polymorphisms (SNP) near the IL28B gene and response to the combined treatments of pegylated-interferon (PegIFN) and ribavirin (RBV) in chronic HCV-infected patients, but without identical conclusions. The aim of this study was to assess impact of the IL28B polymorphisms on the effect of HCV standard treatment using meta-analysis based method.

METHODS

Association studies between polymorphisms of rs12979860 or rs8099917 and response to PegIFN/RBV treatment in chronic HCV patients were retrieved from PubMed. Data of qualified studies on sustained virological response (SVR) in different genotypes were extracted and analyzed using meta-analysis method in Stata 10 software.

RESULTS

Thirty-four papers, containing 46 independent studies, were included in the analysis. In the HCV G1/4 patients without treatment history, individuals carrying rs12979860 CC genotype were more likely to achieve SVR (OR 3.97, 95%CI 3.29-4.80) compared to those carrying CT/TT genotypes. Similar results were observed in the HCV G1/4 patients with unsuccessful or unknown treatment history (OR 3.76, 95%CI 2.67-5.28) or in the patients co-infected with human immunodeficiency virus (OR 5.20, 95%CI 3.04-8.90). However, associations could not be observed in HCV G2/3 patients. For rs8099917, similar results were obtained for genotype TT compared to genotypes TG/GG, indicating that TT genotype was significantly associated with better treatment response in patients infected with genotype 1 or 4 HCV, but not genotype 2 or 3 HCV.

CONCLUSION

Polymorphisms of rs12979860 and rs8099917 near IL28B only associate with the treatment response to PegIFN/RBV in patients infected with HCV genotype 1 or 4 but not with genotype 2 or 3, irrespective of the previous treatment history or HIV co-infected status. Therefore, identification of IL28B genotypes is necessary only in patients infected with relatively difficult-to-treat genotype 1 or 4 HCV.

Response-guided peginterferon-alpha-2b plus ribavirin therapy for chronic hepatitis C patients with genotype 2 and high viral loads

AIMS

  Optimization of the duration of peginterferon-α/ribavirin therapy in patients with hepatitis C virus (HCV) genotype 2 and high viral loads remains to be established. We sought to prospectively optimize the treatment duration based on their virological responses.

METHODS

  Serum HCV RNA levels of less than 50 IU/mL at weeks 2 and 4, and of 50 IU/mL or more at week 4, were defined as a super-rapid virological response (SRVR), rapid virological response (RVR) and late virological response (LVR), respectively. Treatment for 12, 24 or 48 weeks was assigned to the patients with an SRVR, RVR or LVR, respectively. However, patients with an LVR who expressed a desire to receive the standard therapy duration were given the 24-week therapy.

RESULTS

  The overall sustained virological response (SVR) rate was 78.1% (118/151). The SVR rate in the SRVR group was 93.8% (15/16), which was comparable to the 93.0% (66/71) SVR rate in the RVR group. In the LVR patients, the 48-week treatment slightly increased the SVR rate to 76.5% (13/17) compared with the 51.1% (24/47) SVR rate in LVR patients who underwent the standard 24-week treatment. The relapse rate in LVR patients was significantly decreased in patients treated for 48 weeks compared with patients treated for 24 weeks. Multivariate analysis identified the predictive factors for SVR as RVR, prior interferon therapy and total peginterferon-α-2b adherence in patients treated for 24 weeks.

CONCLUSION

  Response-guided therapy may be effective and useful for optimization of the treatment duration.

Impact of interleukin-28B genotype on in vitro and in vivo systems of hepatitis C virus replication

Identification of the relationship between the interleukin (IL)-28B genotype and the effect of peginterferon plus ribavirin treatment has had a great impact on the study of antiviral therapy for patients with chronic hepatitis C virus (HCV) infection. Differential expression levels of interferon-stimulated genes (ISG) in the liver and white blood cells based on the IL-28B genotype, which may in turn lead to differences in outcome of therapy, indicate that previous studies should be re-evaluated taking the effect of the IL-28B single nucleotide polymorphism (SNP) into consideration, although the exact mechanism of how variation in IL-28B SNPs affect HCV eradication remains unknown. These results suggest that the genotypes of multiple cell types, including liver and immune cells, contribute to the efficacy of therapy. Studies using human hepatocyte chimeric mice, in which effector cells of the human adaptive immune response are absent, showed that viral load, ISG expression levels and reduction of HCV RNA by interferon are affected by the IL-28B genotype. Genetic differences among hepatocytes may, therefore, contribute to differences in baseline viral loads and response to interferon therapy. Further studies should be done to clarify the mechanism of action of IL-28B SNP on viral load and effect of interferon treatment. Advances in cell culture systems and human hepatocyte chimeric mice, as well as upcoming in vitro and in vivo experimental systems, provide an effective platform to examine the effects of host and viral genetic variation on infection and response to interferon.

The impact of interferon lambda 3 gene polymorphism on natural course and treatment of hepatitis C

Host genetic factors may predict the outcome and treatment response in hepatitis C virus (HCV) infection. Very recently, three landmark genome-wide association studies identified single nucleotide polymorphisms near the interleukin 28B (IL28B) region which were more frequent in responders to treatment. IL28B encodes interferon (IFN)λ3, a type III IFN involved in host antiviral immunity. Favourable variants of the two most widely studied IL28B polymorphisms, rs12979860 and rs8099917, are strong pretreatment predictors of early viral clearance and sustained viral response in patients with genotype 1 HCV infection. Further investigations have implicated IL28B in the development of chronic HCV infection versus spontaneous resolution of acute infection and suggest that IL28B may be a key factor involved in host immunity against HCV. This paper presents an overview about the biological activity and clinical applications of IL28B, summarizing the available data on its impact on HCV infection. Moreover, the potential usefulness of IFNλ in the treatment and natural history of this disease is also discussed.

The role of viral and host genetics in natural history and treatment of chronic HCV infection

Understanding of the natural history and treatment responsiveness of chronic hepatitis C virus (HCV) infection has evolved rapidly in recent years. Advances in HCV molecular virology and host genetics can now better predict spontaneous clearance and treatment outcomes. HCV genotype is the most important viral factor predicting interferon-α treatment responsiveness; HCV-1 subtype is emerging as a key determinant of the efficacy of direct acting antiviral therapy. Genome-wide association studies have recently identified several clinically important host determinants of the outcomes of peginterferon-α and ribavirin treatment outcome: IL28B polymorphism is associated with spontaneous clearance and treatment responsiveness; ITPA polymorphism protects against ribavirin-induced anaemia and dose reductions; genetic determinants of liver fibrosis progression rate have been proposed. In this review, we evaluate the role of viral and host genetics in the natural history and treatment outcomes of chronic HCV infection, and consider how this knowledge might help individualize clinical management in the era of DAA therapy.

Meta-analysis: the impact of IL28B polymorphisms on rapid and sustained virological response in HCV-2 and -3 patients

BACKGROUND

Recent studies suggested that IL28B polymorphisms may affect rapid and sustained virological response rates in HCV patients infected with genotype 2 or 3.

AIM

To assess the role of IL28B polymorphisms on the virological response in HCV-2 and -3 patients.

METHODS

We performed meta-analysis of studies evaluating the impact of rs12979860 and rs8099917 polymorphisms on rapid and sustained virological response in HCV-2 or -3 patients.

RESULTS

Twenty-three studies involving 3042 patients were included. The first meta-analysis evaluated the impact of rs12979860 polymorphism and included 1963 patients. When compared with rs12979860 CT/TT patients, CC patients had a higher rapid virological response rate (mean difference: 12.9%, 95% CI: 6.5-19.4%, P < 0.001) and a higher sustained virological response rate (mean difference: 4.9%, 95% CI: 0.1-9.8%, P = 0.046). The second meta-analysis evaluated the impact of rs8099917 polymorphism and included 2246 patients. When compared with rs8099917 TG/GG patients, TT patients had a higher rapid virological response rate (mean difference: 14.8%, 95% CI: 7.2-22.4%, P < 0.001) and a higher sustained virological response rate (mean difference: 5.5%, 95% CI: 0.4-10.6%, P = 0.033). When considering only patients treated for 24 weeks, results were unchanged. No potential sources of between-study heterogeneity were identified.

CONCLUSIONS

Favourable IL28B polymorphisms are associated with higher rapid and sustained virological response rates in HCV-2 and -3 patients. However, as the impact on a sustained response is very limited, it is unlikely that IL28B polymorphisms provide additional predictive value when considering other predictors of a sustained response.

Response-guided therapy for patients with chronic hepatitis who have high viral loads of hepatitis C virus genotype 2

AIM

  We evaluated the efficacy of response-guided therapy in patients with hepatitis C virus (HCV) genotype 2.

METHODS

  We studied 105 patients with an HCV genotype 2 load of higher than 5.0 Log IU/mL who received more than 75% of the target dose of pegylated interferon plus ribavirin. Among patients with rapid viral response (RVR; no HCV RNA detected at week 4), 14 selected 16 weeks of therapy (group A), and 28 selected 24 weeks of therapy (group B). Among non-RVR patients, 40 selected 24 weeks of therapy (group C), and 19 selected 48 weeks of therapy (group D).

RESULTS

  All patients in group A and B achieved a sustained viral response (SVR). Clinical characteristics did not differ significantly between groups C and D. However, the proportion of patients in whom HCV RNA disappeared at a later week after starting treatment was higher in group D (P = 0.0578). SVR rate was 73% in C, and 79% in D. Among patients in whom HCV RNA disappeared between weeks 5 and 8, SVR was achieved in 28 (82%) of 34 patients in C and 10 (91%) of 11 patients in D. Among patients whose HCV RNA disappeared between weeks 9 and 12, SVR was achieved in one (20%) of five patients in C and five (63%) of eight patients in D (not statistically significant).

CONCLUSIONS

  16 weeks of combination therapy could achieve an adequate antiviral effect for RVR patients. Extending therapy could not significantly improve SVR rate in non-RVR patients.