Directly acting antivirals for the treatment of chronic hepatitis C: unresolved topics from registration trials

Thiophen urea derivatives as a new class of hepatitis C virus entry inhibitors

To develop unique small-molecule inhibitors of hepatitis C virus (HCV), thiophen urea (TU) derivatives were synthesised and screened for HCV entry inhibitory activities. Among them, seven TU compounds exhibited portent anti-viral activities against genotypes 1/2 (EC₅₀ < 30 nM) and subsequently, they were further investigated; based on the pharmacological, metabolic, pharmacokinetic, and safety profiles, J2H-1701 was selected as the optimised lead compound as an HCV entry inhibitor. J2H-1701 possesses effective multi-genotypic antiviral activity. The docking results suggested the potential interaction of J2H-1701 with the HCV E2 glycoprotein. These results suggest that J2H-1701 can be a potential candidate drug for the development of HCV entry inhibitors.

Validated High-performance Liquid Chromatography Method for the Determination of JW5624, A New Class Of Hepatitis C Virus Inhibitor, in Rat Plasma and its Application in the Pharmacokinetic Study of JW5624

We developed unique small-molecule inhibitors of hepatitis C virus (HCV), which had potent activity for HCV entry inhibition and multi-genotypic antiviral activity. In this study, a sensitive and reliable method for the quantitation of JW5624 in rat plasma was developed and validated using high performance liquid chromatography. Chromatographic separation was achieved using a reversed-phase (C18) column. The mobile phase, 0.02 M ammonium acetate buffer:acetonitrile (30:70, v/v), was run at a flow rate of 1.0 mL/min, and the column eluent was monitored using an ultraviolet detector at 254 nm at room temperature. The retention times of sildenafil (an internal standard), and JW5624 were approximately 5.9 and 7.3 min, respectively. The detection limit of JW5624 in rat plasma was 0.03 μg/mL. Pharmacokinetic parameters of JW5624 was evaluated after intravenous (i. v.; at doses of 5 mg/kg) and oral (p.o.; at doses of 10 mg/kg) administration of JW5624 in rats. After p.o. administration (10 mg/kg) of JW5624, F value was approximately 71.0%. These results suggest that JW5624 can be a potential candidate drug for the development of HCV entry inhibitors.

A novel, potent, and orally bioavailable thiazole HCV NS5A inhibitor for the treatment of hepatitis C virus

A medicinal chemistry program based on the small-molecule HCV NS5A inhibitor daclatasvir has led to the discovery of dimeric phenylthiazole compound 8, a novel and potent HCV NS5A inhibitor. The subsequent SAR studies and optimization revealed that the cycloalkyl amide derivatives 27a-29a exhibited superior potency against GT1b with GT1b EC₅₀ values at picomolar concentration. Interestingly, high diastereospecificity for HCV inhibition was observed in this class with the (1R,2S,1'R,2'S) diastereomer displaying the highest GT1b inhibitory activity. The best inhibitor 27a was found to be 3-fold more potent (GT1b EC₅₀ = 0.003 nM) than daclatasvir (GT1b EC₅₀ = 0.009 nM) against GT1b, and no detectable in vitro cytotoxicity was observed (CC₅₀ > 50 μM). Pharmacokinetic studies demonstrated that compound 27a had an excellent pharmacokinetic profiles with a superior oral exposure and desired bioavailability after oral administration in both rats and dogs, and therefore it was selected as a developmental candidate for the treatment of HCV infection.

Unexpected Response Profiles Seen in Hepatitis C Virus-Infected Patients Treated with Sofosbuvir Plus Ribavirin: Five Case Reports

Direct-acting antivirals (DAAs) have been proved as potent agents in the new era of Hepatitis C therapeutics. DAA has evolved to prove highly efficacious treatment rates and sustained virological response in hepatitis C virus (HCV)-treated patients and has shown minimal side effects, but in this study, we reported five cases that showed unusual response toward the use of DAA. The diagnosis was an unusual response of abruptly high viral titers and liver function tests (LFTs) in patients who received DAA combination therapy. The patients received sofosbuvir (400 mg) and ribavirin for 6 months. Although 6-month long recommended DAA combination therapy with ribavirin cleared HCV after 6 months, during the treatment period, five patients experienced unusually and unexpectedly high viral loads and LFTs level in the middle of therapy tenure and then sudden decline of viral titers after completion of treatment. This is the first study to describe the unusual response shown by patients treated with sofosbuvir-based combined therapy that experienced abrupt and marked rise in viral loads during the initial months of treatment followed by sudden elimination of virus during last 2 months of treatment. Although satisfactory response to DAA is well reported, clinicians and policy makers should deliberate upon the exceptions and ensure the proper implementation of International guidelines with modifications according to this population, if necessary.

A Potent, Selective, and Orally Bioavailable HCV NS5A Inhibitor for Treatment of Hepatitis C Virus: (S)-1-((R)-2-(Cyclopropanecarboxamido)-2-phenylacetyl)-N-(4-phenylthiazol-2-yl)pyrrolidine-2-carboxamide

Starting from the initial lead 4-phenylthiazole 18, a modest HCV inhibitor (EC₅₀ = 9440 nM), a series of structurally related thiazole derivatives has been identified as a novel chemical class of potent and selective HCV NS5A inhibitors. The introduction of a carboxamide group between the thiazole and pyrrolidine ring (42) of compound 18 resulted in a dramatic increase in activity (EC₅₀ = 0.92 nM). However, 42 showed only moderate pharmacokinetic properties and limited oral bioavalability of 18.7% in rats. Further optimization of the substituents at the 4-position of the thiazole ring and pyrrolidine nitrogen of the lead compound 42 led to the identification of compound 57, a highly potent and selective NS5A inhibitor of HCV (EC₅₀ = 4.6 nM), with greater therapeutic index (CC₅₀/EC₅₀ > 10000). Pharmacokinetic studies revealed that compound 57 had a superior oral exposure and desired bioavailability of 45% after oral administration in rats.

Human heme oxygenase 1 is a potential host cell factor against dengue virus replication

Dengue virus (DENV) infection and replication induces oxidative stress, which further contributes to the progression and pathogenesis of the DENV infection. Modulation of host antioxidant molecules may be a useful strategy for interfering with DENV replication. In this study, we showed that induction or exogenous overexpression of heme oxygenase-1 (HO-1), an antioxidant enzyme, effectively inhibited DENV replication in DENV-infected Huh-7 cells. This antiviral effect of HO-1 was attenuated by its inhibitor tin protoporphyrin (SnPP), suggesting that HO-1 was an important cellular factor against DENV replication. Biliverdin but not carbon monoxide and ferrous ions, which are products of the HO-1 on heme, mediated the HO-1-induced anti-DENV effect by non-competitively inhibiting DENV protease, with an inhibition constant (Ki) of 8.55 ± 0.38 μM. Moreover, HO-1 induction or its exogenous overexpression, rescued DENV-suppressed antiviral interferon response. Moreover, we showed that HO-1 induction by cobalt protoporphyrin (CoPP) and andrographolide, a natural product, as evidenced by a significant delay in the onset of disease and mortality, and virus load in the infected mice’s brains. These findings clearly revealed that a drug or therapy that induced the HO-1 signal pathway was a promising strategy for treating DENV infection.

In Silico Design and Experimental Validation of siRNAs Targeting Conserved Regions of Multiple Hepatitis C Virus Genotypes

RNA interference (RNAi) is a post-transcriptional gene silencing mechanism that mediates the sequence-specific degradation of targeted RNA and thus provides a tremendous opportunity for development of oligonucleotide-based drugs. Here, we report on the design and validation of small interfering RNAs (siRNAs) targeting highly conserved regions of the hepatitis C virus (HCV) genome. To aim for therapeutic applications by optimizing the RNAi efficacy and reducing potential side effects, we considered different factors such as target RNA variations, thermodynamics and accessibility of the siRNA and target RNA, and off-target effects. This aim was achieved using an in silico design and selection protocol complemented by an automated MysiRNA-Designer pipeline. The protocol included the design and filtration of siRNAs targeting highly conserved and accessible regions within the HCV internal ribosome entry site, and adjacent core sequences of the viral genome with high-ranking efficacy scores. Off-target analysis excluded siRNAs with potential binding to human mRNAs. Under this strict selection process, two siRNAs (HCV353 and HCV258) were selected based on their predicted high specificity and potency. These siRNAs were tested for antiviral efficacy in HCV genotype 1 and 2 replicon cell lines. Both in silico-designed siRNAs efficiently inhibited HCV RNA replication, even at low concentrations and for short exposure times (24h); they also exceeded the antiviral potencies of reference siRNAs targeting HCV. Furthermore, HCV353 and HCV258 siRNAs also inhibited replication of patient-derived HCV genotype 4 isolates in infected Huh-7 cells. Prolonged treatment of HCV replicon cells with HCV353 did not result in the appearance of escape mutant viruses. Taken together, these results reveal the accuracy and strength of our integrated siRNA design and selection protocols. These protocols could be used to design highly potent and specific RNAi-based therapeutic oligonucleotide interventions.

Hydroxychloroquine augments early virological response to pegylated interferon plus ribavirin in genotype-4 chronic hepatitis C patients

The therapeutic effect of pegylated interferon (peg-IFN) alfa-2a combined with ribavirin (RBV) on chronic hepatitis C Egyptian patients is low and further efforts are required to optimize this therapy for achievement of higher rates of virological response. This study aimed to evaluate the safety and efficacy of hydroxychloroquine (HCQ) in combination with pegylated interferon plus ribavirin on early virological response (EVR) in chronic hepatitis C Egyptian patients. Naïve 120 Egyptian patients with chronic hepatitis C virus infection were divided into two groups. Group 1 have administered the standard of care therapy (pegylated interferon alfa-2a plus ribavirin) for 12 weeks, (n = 60). Group 2 have administered hydroxychloroquine plus standard of care therapy for 12 weeks, (n = 60). Therapeutics included hydroxychloroquine (200 mg) oral twice daily, peginterferon alfa-2a (160 μg) subcutaneous once weekly and oral weight-based ribavirin (1000-1200 mg/day). Baseline characteristics were similar in the two groups. The percentage of early virological response was significantly more in patients given the triple therapy than in patients given the standard of care [54/60 (90%) vs. 43/60 (71.7%); P = 0.011; respectively]. Biochemical response at week 12 was also significantly higher in patients given the triple therapy compared with the standard of care [58/60 (96.7%) vs. 42/60 (70%); P < 0.001; respectively]. Along the study, the observed adverse events were mild and similar across treatment groups. Addition of hydroxychloroquine to pegylated interferon plus ribavirin improves the rate of early virological and biochemical responses in chronic hepatitis C Egyptian patients without an increase in adverse events. J. Med. Virol. 88:2170-2178, 2016. © 2016 Wiley Periodicals, Inc.

Hepatitis C virus: A global view

Hepatitis C virus (HCV) is a global challenge; 130-175 million are chronically infected. Over 350000 die each year from HCV. Chronic HCV is the primary cause of cirrhosis, hepatocellular carcinoma (HCC), and end-stage liver disease. Management of chronic HCV is aimed at preventing cirrhosis, reducing the risk of HCC, and treating extra hepatic complications. New treatments for chronic HCV has been devoted based on direct-acting antivirals, as pegylated interferon (peginterferon) is responsible for many side effects and limits treatment access. Sofosbuvir is the first compound to enter the market with Peginterferon-free combination regimens.

Role of genetic polymorphisms in hepatitis C virus chronic infection

AIM: To analyze the host genetics factors influencing the clinical course and the response to antiviral treatment in patients with chronic hepatitis C (CHC).

METHODS: We conducted an electronic search on the PubMed and MEDLINE (2000-2014) databases and Cochrane library (2000-2014). A total of 73 articles were retrieved and their data were extensively evaluated and discussed by the authors and then analyzed in this review article.

RESULTS: Several studies associated polymorphisms in the interleukin 28B gene on chromosome 19 (19q13.13) with a spontaneous viral clearance in acute hepatitis C and with the response to pegylated interferon (Peg-IFN)-based treatment in chronic hepatitis C patients. Other investigations demonstrated that inosine triphosphate pyrophosphatase genetic variants protect hepatitis C virus-genotype-1 CHC patients from ribavirin-induced anemia, and other studies that a polymorphism in the patatin-like phospholipase domain-containing protein 3 was associated with hepatic steatosis in CHC patients. Although not conclusive, some investigations suggested that the vitamin D-associated polymorphisms play an important role in the achievement of sustained virologic response in CHC patients treated with Peg-IFN-based antiviral therapy. Several other polymorphisms have been investigated to ascertain their possible impact on the natural history and on the response to treatment in patients with CHC, but the data are preliminary and warrant confirmation.

CONCLUSION: Several genetic polymorphisms seem to influence the clinical course and the response to antiviral treatment in patients with CHC, suggesting individualized follow up and treatment strategies.

Diabetes mellitus and advanced liver fibrosis are risk factors for severe anaemia during telaprevir-based triple therapy

BACKGROUND & AIMS

Adding telaprevir to pegylated-interferon and ribavirin increased both response rates and side effects of hepatitis C virus (HCV) treatment. We identified variables associated with severe anaemia during telaprevir-based triple therapy.

METHODS

An observational study was performed on 142 HCV-infected patients between June 2011 and March 2012. All subjects completed 12 weeks of telaprevir-based triple therapy or discontinued early because of anaemia. Severe anaemia was defined by a haemoglobin≤8.9 g/dl; advanced fibrosis was determined by Fib-4≥3.25.

RESULTS

The 47 (33%) patients who developed severe anaemia were similar to those who did not in sex, race, and prior response to dual therapy, but they were more likely to have diabetes (23.4% vs. 6.3%, P<0.01), advanced fibrosis (46.8% vs. 29.5%, P=0.04) and a history of anaemia during previous dual therapy (29.7% vs. 11.4%, P=0.02). Patients developing severe anaemia were older (59 vs. 56 years, P=0.02), had lower baseline platelet counts (134 vs. 163×10(9) /L, P=0.04), haemoglobin (14.0 vs. 15.0 g/dl, P<0.01), estimated glomerular filtration rate (79 vs. 90 ml/min/1.73 m2, P=0.03) and a higher median ribavirin/weight ratio (14.9 vs. 13.2 mg/kg, P<0.01). In multivariable logistic regression, presence of diabetes (OR=5.61, 95% CI: 1.59-19.72), Fib-4≥3.25 (OR=3.09, 95% CI: 1.28-7.46), higher ribavirin/weight ratio (OR=1.31 per mg/kg, 95% CI: 1.13-1.52) and lower baseline haemoglobin (OR=0.57 per g/dl, 95% CI, 0.41-0.80) were independently associated with developing severe anaemia.

CONCLUSIONS

Severe anaemia occurred in one-third of patients receiving telaprevir-based triple therapy. Risk was greater in patients with diabetes, advanced liver fibrosis, higher ribavirin/weight ratio and lower baseline haemoglobin.

Sofosbuvir for the treatment of chronic hepatitis C: between current evidence and future perspectives

In recent years, clinical research in the field of new treatments for chronic hepatitis C (HCV) has been devoted to developing regimens based on direct-acting antivirals (DAAs), with the goal of increasing treatment efficacy and improving tolerability and safety. This can be achieved by Peginterferon (PegIFN)-free anti-HCV regimens, as PegIFN is responsible for many side effects and limits treatment access due to contraindications in some patient categories. Sofosbuvir (SOF) is the first compound to enter the market with IFN-free combination regimens; it belongs to the nucleotide inhibitors of viral polymerase NS5B and acts as a chain terminator during the HCV replication process, exhibiting pan-genotypic antiviral activity with a high barrier to resistance. Clinical trials in HCV genotype 2/3 patients have demonstrated optimal efficacy in HCV-2, where the combination SOF/ribavirin (Rbv) for 12 weeks resulted in >90% sustained virological response (SVR) rates, while HCV-3 patients with advanced liver fibrosis and previous failure to PegIFN plus Rbv therapy still require individualized and optimized treatment strategies. Historically difficult-to-treat genotypes HCV-1, −4–6 can benefit from reduced duration of PegIFN plus SOF and Rbv, while IFN-free regimens in these patients will be based on SOF in combination with other DAA classes. Due to an optimal tolerability and safety profile with no significant drug-to-drug interactions, SOF is currently undergoing clinical trials in the setting of pre- and post-liver transplantation and HIV-coinfected patients, with the objective to address the until now unmet need for safe and efficient treatment in these populations. This article provides an overview of SOF features and the main clinical trials, discussing key results and potential future developments.

Limited utility of ITPA deficiency to predict early anemia in HCV patients with advanced fibrosis receiving Telaprevir

Background

Severe anemia is a common side effect of Pegylated Interferon + Ribavirin (PR) and Telaprevir (TVR) in hepatitis C virus (HCV) genotype 1 patients with advanced fibrosis or cirrhosis (F3–F4). Inosine triphosphatase (ITPA) genetic variants are associated with RBV- induced anemia and dose reduction.

Aim

To test the association of ITPA polymorphisms rs1127354 and rs7270101 with hemoglobin (Hb) decline, need for RBV dose reduction (RBV DR), erythropoietin (EPO) support and blood transfusions during the first 12 weeks of TVR triple therapy.

Materials and Methods

69 consecutive HCV-1 patients (mean age 57 years) with F3-F4 who received PR and TVR were genotyped for ITPA polymorphisms rs1127354 and rs7270101. Estimated ITPA deficiency was graded on severity (0–3, no deficiency/mild/moderate/severe).

Results

ITPA deficiency was absent in 48 patients (70%), mild in 12 (17%) and moderate in 9 patients (13%). Mean week 4 Hb decline was higher in non ITPA deficient patients (3,85 g/dL) than in mildly or moderately ITPA deficient patients (3,07 g/dL and 1,67 g/dL, p<0.0001). Grade 3–4 anemia developed in 81% non ITPA deficient patients versus 67% mild deficient and 55% moderate deficient patients (p = ns). Grade of ITPA deficiency was not associated with RbvDR (no deficiency: 60%, mild: 58%, moderate: 67%; p = ns), EPO use (no deficiency: 65%, mild: 58%, moderate:56%; p = ns) or need for blood transfusion (no deficiency: 27%, mild: 17%, moderate: 33%; p = ns).

Conclusions

In patients with F3–F4 chronic hepatitis C receiving TVR based therapy, ITPA genotype does not impact on the management of early anemia.

Peg-interferon plus ribavirin with or without boceprevir or telaprevir for HCV genotype 1: a meta-analysis on the role of response predictors. PLoS One. 2014;9:e94542. [PMID: 24728219 PMCID: PMC3984165 DOI: 10.1371/journal.pone.0094542]

Background & aim

To compare the efficacy of pegylated-interferon (Peg-IFN) α-2a or α-2b and ribavirin given as dual therapy versus triple therapy (Peg-IFN and ribavirin plus boceprevir or telaprevir) in patients with HCV-1 chronic hepatitis naïve for anti-HCV therapy or relapsers to dual therapy in relation to the presence of constitutional, clinical and virological predictors of treatment response.

Methods

Included in the meta-analysis were studies meeting these criteria: original data from randomized trials on the efficacy of dual versus triple therapy in therapy-naïve patients or relapsers; at least one primary outcome clearly defined: sustained virological response in patients with or without rapid virological response (RVR), with genotype 1a or 1b, low or high HCV load, IL28-B CC or non-CC genotype, mild or severe fibrosis; odds ratio estimates of relative risk (RR) and 95% confidence intervals; English language; and published up to the end of June 2013.

Results

Seven original studies met the inclusion criteria, allowing a meta-analysis on 3,652 patients. Triple therapy was more effective than dual, regardless of IL-28B genotype, HCV sub-genotype, liver fibrosis, and baseline HCV load. In 1,045 patients who achieved RVR, SVR was more frequently achieved with dual therapy (RR = 1.11; p = 0.002) than triple. The same results were achieved when only the therapy-naïve patients were considered.

Conclusions

Triple therapy provides a significantly higher SVR rate than dual therapy, but dual therapy obtains a significantly higher SVR rate in patients with RVR. The data stress the clinical importance of a 4-week lead-in phase in direct-acting antiviral-based treatment.

Management of anemia induced by triple therapy in patients with chronic hepatitis C: challenges, opportunities and recommendations

The addition of protease inhibitors, boceprevir or telaprevir, to peginterferon+ribavirin (PegIFN/RBV) increases the frequency as well as the severity, and hence, clinical relevance of anemia, which has now become one of the major complications associated with triple therapy. Most significant factors associated with anemia in patients receiving triple therapy include older age, lower body mass index (BMI), advanced fibrosis, and lower baseline hemoglobin. The variability in inosine triphosphate pyrophosphatase (ITPA) gene, which encodes a protein that hydrolyses inosine triphosphate (ITP), has been identified as an essential genetic factor for anemia both in dual and triple therapy. The correct management of anemia is based on anticipation, characterization and therapeutic management. Basically, anemia can be characterized in 3 types: ferropenic (mostly in fertile women), thalassemic type hemolytic anemia, and anemia from chronic processes. Functional deficit of iron should also be excluded in patients with normal ferritin and lower saturation of transferrin. Ribavirin dose reduction and epoetin, sequentially, are indicated in the management of anemia. Epoetin non-response can be caused by lack of time, type of anemia, functional iron deficit or erythropoietin resistance. In the transplantation setting, adding a protease inhibitor to PegIFN/RBV results in a significant increase in the incidence and severity of anemia and, as a consequence, a greater need for epoetin, transfusions, and ribavirin dose reductions. Packed red cell transfusions are utilized when hemoglobin decreases to less than 7.5g/dl and/or there are clinical symptoms and/or there is no response to other therapeutic measures.

Telaprevir in a patient with chronic hepatitis C and cryoglobulinemic glomerulonephritis

Mixed cryoglobulinemia (MC), the most common extrahepatic manifestation of HCV, may lead to renal involvement ranging from mild urinary abnormalities to nephritic syndrome, eventually evolving to renal failure requiring renal replacement therapy. HCV eradication with pegylated interferon (PEG-IFN) and ribavirin (RBV) is the only curative treatment for MC-related membranoproliferative glomerulonephritis. The addition of directly acting antivirals (DAAs) to PEG-IFN and RBV has significantly improved sustained virological response rates in HCV genotype 1 patients. Safety and efficacy of this regimen in patients with membranoproliferative glomerulonephritis has not been proved yet. Here, we report the case of a woman with HCV-1-related cryoglobulinemic membranoproliferative glomerulonephritis presenting with severe nephritic syndrome and rapidly progressive renal failure, who received successful treatment with the DAA telaprevir in conjunction with PEG-IFN and RBV. Triple therapy was safe and effective, leading to HCV eradication and complete resolution of acute renal failure.

Cirrhosis and rapid virological response to peginterferon plus ribavirin determine treatment outcome in HCV-1 IL28B rs12979860 CC patients

BACKGROUND

The rs12979860 CC genotype of the interleukin 28B (IL28B) polymorphism is associated with high rates of sustained virological response (SVR) to peginterferon (PegIFN) and ribavirin (Rbv) in hepatitis C virus genotype-1 (HCV-1) patients. The impact of baseline predictors of treatment outcome and their interplay with viral kinetics in HCV-1 CC patients has not been fully evaluated.

AIM

To identify baseline and on-therapy predictors of treatment failure in HCV-1 IL28B CC patients.

METHODS

Treatment-naïve HCV-1 patients, compliant to PegIFN and Rbv who did not discontinue treatment for nonvirological reasons, were analyzed.

RESULTS

109 HCV-1 IL28B CC were studied. Sixty were males, 39 with BMI >25, 69 with >600,000 IU/mL HCV RNA, 15 with HCV1a, and 30 with cirrhosis. Overall, 75 (69%) achieved an SVR; cirrhosis was the only baseline predictor of treatment failure (OR: 2.58, 95% CI: 1.07-6.21) as SVR rates were 53% in cirrhotics versus 75% in noncirrhotics (P = 0.03). HCV RNA undetectability (<50 IU/mL) at week 4 (RVR) was achieved by 58 patients (53%). The SVR rates were independent of RVR in noncirrhotics, 76% (34/45) RVR (+) and 74% (25/34) RVR (-) (P = 0.9). In cirrhotic patients, SVR rates were significantly higher in RVR (+) compared to RVR (-) (10/13 (77%) versus 6/17 (35%) P = 0.03).

CONCLUSIONS

In HCV-1 IL28B CC patients, cirrhosis is the only clinical baseline predictor of PegIFN and Rbv treatment failure. However, in IL28B CC cirrhotics, the achievement of RVR identifies those patients who still have high rates of SVR to Peg-IFN/Rbv therapy.

How to optimize HCV therapy in genotype 2 patients

Hepatitis C Virus (HCV) Genotype 2 accounts for 10% of the patients with chronic HCV worldwide. The current standard of care (SOC) in these patients is 24 weeks of Pegylated Interferon (PEG-IFN) plus Ribavirin (RBV), with sustained virological response rates (SVR) of 80-90%. However, there are subgroups of patients with HCV-2, such as those with advanced fibrosis/cirrhosis, in whom SVR rates are still suboptimal, and highly responsive groups in whom SVR rates reach 95%. Treatment optimization is necessary to maximize efficacy in the former group and reduce treatment-related side effects in the latter. Unfortunately, any attempt to modify the duration or dosing of the SOC according to baseline factors has been disappointing and should not be continued at present. On the other hand on-treatment HCV RNA kinetics are fundamental for individualized treatment regimens because achieving negative HCV RNA at week 4 (rapid virological response, RVR) is the key factor when the duration of PEG-IFN/RBV is tailored in HCV-2 patients. Several studies have shown that treatment can be shortened to 16 weeks in HCV-2 patients with a RVR, without increasing the risk of post-treatment relapse, thus increasing tolerance to treatment while reducing healthcare costs. On the other hand, patients who do not achieve a RVR correspond to a population of difficult-to-cure HCV-2 patients who need alternative treatment strategies which are not yet available.

Meta-analysis: implications of interleukin-28B polymorphisms in spontaneous and treatment-related clearance for patients with hepatitis C

BACKGROUND

Since 2009, several studies have identified single-nucleotide polymorphisms (SNPs) near the gene encoding for interleukin (IL)-28 (IL28B) that are strongly associated with spontaneous and treatment-induced hepatitis C virus (HCV) clearance. Because this large amount of data includes some inconsistencies, we consider assessment of the global estimate for each SNP to be essential.

METHODS

Relevant studies assessing IL28B polymorphisms associated with sustained virologic response (SVR) and spontaneous clearance (SC) were identified from a literature search of PubMed up to 9 July, 2012. Studies were eligible studies if they included patients infected with HCV or HCV/HIV, or assessed any SNP located within or near the IL28B gene, SVR data available under standard treatment, and/or SC data in patients with acute HCV infection. Pooled odds ratios were estimated by fixed or random effects models when appropriate. Variables such as HCV genotype, ethnicity, and type of co-infection were studied.

RESULTS

Of 282 screened studies, 67 were selected for SVR and 10 for SC. In total, 20,163 patients were studied for SVR and 3,554 for SC. For SVR, we found that all SNPs showed strong associations in patients with HCV genotypes 1 and 4, whereas the pooled ORs were almost three times lower for genotypes 2 and 3 (rs12979860 and rs8099917). Regarding ethnicity, the SNP most associated with SVR was rs12979860 in white patients, whereas in East Asians it seemed to be rs8099917. The most studied SNP (rs12979860) showed similar results for patients co-infected with HCV/HIV, as for those infected with HCV only. Finally, rs12979860 and rs8099917 both appeared to be associated with SC.

CONCLUSIONS

IL28B polymorphisms influence both the outcome of interferon treatment and the natural clearance of HCV. However we did not identify a universal predictor SNP, as the best genetic markers differed depending on patient ethnicity, genotype, and type of infection. Nevertheless, our results may be useful for more precise treatment decision-making.