Predicting sustained virological responses in chronic hepatitis C patients treated with peginterferon alfa-2a (40 KD)/ribavirin

Optimizing the current therapy for chronic hepatitis C virus: peginterferon and ribavirin dosing and the utility of growth factors

Achieving a sustained virologic response depends on the patient achieving three sequential independent milestones: virologic response, maintaining this response throughout treatment, and not relapsing after treatment has been completed. The ability to achieve these milestones depends on the doses of interferon/peginterferon and ribavirin used and on whether treatment with these medications is adjusted, interrupted, or prematurely discontinued in response to adverse events. This review discusses strategies to optimize peginterferon and ribavirin dosing and the impact that growth factors may have on the ability to achieve a sustained virologic response.

Sequence variation in hepatitis C virus nonstructural protein 5A predicts clinical outcome of pegylated interferon/ribavirin combination therapy

A substantial proportion of hepatitis C virus (HCV)-1b-infected patients still do not respond to interferon-based therapy. This study aims to explore a predictive marker for the ultimate virological response of HCV-1b-infected patients treated with pegylated interferon/ribavirin (PEG-IFN/RBV) combination therapy. Nonstructural protein 5A (NS5A) sequences of HCV in the pretreated sera of 45 patients infected with HCV-1b were analyzed. The mean number of mutations in the variable region 3 (V3) plus its upstream flanking region of NS5A (amino acid 2334-2379), referred to as IFN/RBV resistance-determining region (IRRDR), was significantly higher for HCV isolates obtained from patients who later achieved sustained virological response (SVR) by PEG-IFN/RBV than for those in patients undergoing non-SVR. The receiver operating characteristic curve analysis estimated six mutations in IRRDR as the optimal threshold for SVR prediction. Indeed, 16 (76%) of 21 SVR, but only 2 (8%) of 24 non-SVR, had HCV with six or more mutations in IRRDR (IRRDR > or = 6) (P < 0.0001). All of 18 patients infected with HCV of IRRDR of 6 or greater examined showed a significant (> or =1 log) reduction or disappearance of serum HCV core antigen titers within 24 hours after initial dose of PEG-IFN/RBV, whereas 10 (37%) of 27 patients with HCV of IRRDR of 5 or less did (P < 0.0001). The positive predictive value of IRRDR of 6 or greater for SVR was 89% (16/18; P = 0.0007), with its negative predictive value for non-SVR being 81% (22/27; P = 0.0008).

CONCLUSION

A high degree (> or =6) of sequence variation in IRRDR would be a useful marker for predicting SVR, whereas a less diverse (< or =5) IRRDR sequence predicts non-SVR.

Role of rapid virological response in prediction of sustained virological response to Peg-IFN plus ribavirin in HCV / HIV co-infected individuals

The objective of the study was to evaluate the role of rapid virological response (RVR) in predicting sustained virological response (SVR) rates to hepatitis C virus (HCV) therapy. 65 HIV / HCV co-infected patients commenced HCV treatment per protocol. HIV / HCV patients with a mean CD4 count of 502 were treated for 24-48 weeks depending on genotype. Virological response was assessed at weeks 4 (RVR), 12 [early virological response (EVR)], 24, at end of treatment (EOTR) and 24 weeks post-completion of treatment (SVR). Primary end-point was defined as undetectable HCV RNA at 24 weeks post-treatment completion. Fifty-five per cent of co-infected patients were on highly active anti-retroviral therapy. A majority of patient group were male. 60% of HIV / HCV patients achieved SVR (35% genotype 1 / 4; 77% genotype 2 / 3). 24 HIV / HCV patients achieved undetectable HCV levels compared with baseline by week 4. The positive predictive value (PPV) of RVR at week 4 for subsequent SVR in HIV-HCV co-infected patients was 100%; the negative predictive value (NPV) was 57%. Significant variables associated with SVR were: (i) lower median pre-treatment HCV viral load, (ii) genotype 2 / 3 disease and (iii) achievement of RVR. Independent variables associated with RVR were low pre-treatment HCV viral load and genotype 2 / 3 disease. Achievement of RVR, a negative HCV-PCR, at week 4 of treatment is predictive of SVR in this cohort of patients. This may be used to guide optimal treatment duration in patient groups. More significantly, the data serve to highlight the subgroup of patients who, on achieving RVR, should be actively supported to complete HCV treatment with full dose therapy, especially patients co-infected with G2 / 3 disease for whom 6 months' full dose therapy may be sufficient to obtain a SVR.

Extended-therapy duration for chronic hepatitis C, genotype 1: The long and the short of it

With pegylated interferon and ribavirin, more than half of all chronically-infected hepatitis C patients can achieve a sustained virologic response; however, patients with genotype 1 infections and those with other poor prognostic factors have relatively inferior treatment response rates. Since new therapies are still years away from approval, it is incumbent upon providers to maximize the therapeutic efficacy of today’s treatment. The later the virus is undetectable in serum during treatment, the less likely it will be eradicated. Patients with a delayed or slow virologic response to therapy (at least a 2-log₁₀ decrease in baseline hepatitis C RNA yet detectable viremia at 12 wk of therapy and undetectable virus 12 wk subsequently) may, therefore, benefit from an extended therapy course beyond one of standard duration. Although higher rates of treatment discontinuation may plague this approach, 72 wk of treatment for genotype 1-infected slow-responders may improve response rates and diminish relapse rates relative to those of 48 wk. Based on data from both viral kinetic and clinical studies, therapy prolongation in slow responders may be a reasonable strategy to improve response rates in these treatment-refractory patients.

The use of molecular assays in the management of viral hepatitis

Molecular assays are instrumental in the clinical management of viral hepatitis. During the past years, a wide variety of molecular assays have been developed and implemented. This considerably improved the understanding of the natural history and pathogenesis of Hepatitis B virus (HBV), Hepatitis C virus (HCV) or Hepatitis delta virus (HDV) hepatitis, but also caused uncertainties in the selection of the most appropriate assays for clinical requirements. Indeed, a rational choice and application of these assays requires adequate knowledge of the performance of the single test. Moreover, the choice of the most accurate assay for patients' needs and physicians' objectives, needs to be oriented to specific contexts, such as diagnosis, management or treatment. In the past, a hurdle in the routine use of assays for hepatitis viruses nucleic acid quantification was represented by the availability of only "home brew" methods which lacked standardization. Major improvement in addressing the use of molecular assays for viral hepatitis has been derived from recent standardization procedures that allowed a comparison between different tests after results were given as International Units. In addition, it should be reminded that, before getting into the market, molecular assays should be approved by European regulation authorities and validated using internationally recognized standards. A subsequent clinical validation should address the diagnostic accuracy of the assay. These proceedings have the aim of identifying which molecular tests, among those currently available, meet clinical requirements for each specific application.

Interferon signaling and treatment outcome in chronic hepatitis C

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease worldwide. The current standard therapy for chronic hepatitis C (CHC) consists of a combination of pegylated IFN alpha (pegIFNalpha) and ribavirin. It achieves a sustained viral clearance in only 50-60% of patients. To learn more about molecular mechanisms underlying treatment failure, we investigated IFN-induced signaling in paired liver biopsies collected from CHC patients before and after administration of pegIFNalpha. In patients with a rapid virological response to treatment, pegIFNalpha induced a strong up-regulation of IFN-stimulated genes (ISGs). As shown previously, nonresponders had high expression levels of ISGs before therapy. Analysis of posttreatment biopsies of these patients revealed that pegIFNalpha did not induce expression of ISGs above the pretreatment levels. In accordance with ISG expression data, phosphorylation, DNA binding, and nuclear localization of STAT1 indicated that the IFN signaling pathway in nonresponsive patients is preactivated and refractory to further stimulation. Some features characteristic of nonresponders were more accentuated in patients infected with HCV genotypes 1 and 4 compared with genotypes 2 and 3, providing a possible explanation for the poor response of the former group to therapy. Taken together with previous findings, our data support the concept that activation of the endogenous IFN system in CHC not only is ineffective in clearing the infection but also may impede the response to therapy, most likely by inducing a refractory state of the IFN signaling pathway.

Latinos and chronic hepatitis C: a singular population

Latinos are the largest minority in the USA and have higher rates of HCV infection. The course of chronic hepatitis C in Latinos is more aggressive, with higher risk to develop cirrhosis than any other ethnic group or race. Available information suggests that more rapid progression of liver disease is aggravated by decreased efficacy to treatment with available therapies. The causes for more aggressive progression and decreased efficacy of treatment are complex. Factors related to metabolic syndrome, insulin resistance, and hepatic steatosis are important, as well as genetic differences, not only for metabolic syndrome but for immune responses to interferon. In addition, there are substantial barriers for Latinos to access medical care. Language, cultural differences, and socioeconomic factors, including lack of medical insurance, more frequent use of alcohol, and possible medical care provider bias, are significant obstacles to diagnosis and treatment. The severity of the liver disease and the association to metabolic syndrome medical conditions justify that Latinos be considered a special population with urgent need of intervention strategies. In this article we present all the available evidence on epidemiology, natural history of chronic hepatitis C, and efficacy of anti-HCV therapy in Latinos infected with HCV.

Histological benefits of virological response to peginterferon alfa-2a monotherapy in patients with hepatitis C and advanced fibrosis or compensated cirrhosis

BACKGROUND

Patients with chronic hepatitis C virus and advanced fibrosis or cirrhosis are at risk for disease progression and hepatic decompensation.

AIM

To determine the effects on hepatic histology of treatment with peginterferon alfa-2a (90 or 180 mug/week) or interferon alfa-2a (3 million units three times weekly) for 48 weeks in patients with paired biopsies.

METHODS

Liver biopsies were obtained at baseline and 6 months after end of treatment. Histological and virological responses were compared.

RESULTS

Patients attaining sustained virological response (n = 40) demonstrated the greatest improvements in fibrosis (-1.0, P < 0.0001) and inflammation (-0.65, P < 0.0001). Patients who cleared hepatitis C virus during treatment, but later relapsed (n = 59), experienced less improvement in fibrosis (-0.04, P < 0.0001) and inflammation (-0.14, P = 0.0768). Nonresponders (n = 85) showed no significant improvement in inflammation or fibrosis. Multiple regression analysis showed that the only factors contributing to improvement in fibrosis were sustained virological response (vs. nonresponder, P = 0.0005; vs. relapse, P = 0.7525) and body mass index < or =30 kg/m2 (P = 0.0995).

CONCLUSIONS

These findings indicate that virological response to peginterferon alfa-2a improves inflammation and fibrosis in hepatitis C virus patients with advanced fibrosis or cirrhosis. Improving virological response and maintaining ideal body weight are critical for achieving optimal histological outcomes in hepatitis C virus patients.

Early and accurate prediction of Peg-IFNs/ribavirin therapy outcome in the individual patient with chronic hepatitis C by modeling the dynamics of the infected cells

A novel biomathematical model that analyzes the combined alanine transaminase (ALT) and viral-load kinetics during the first month of pegylated interferon (Peg-IFN) plus ribavirin (RBV) therapy was successfully applied in 90 of 97 (93%) chronic hepatitis C patients in order to compute the number of infected cells at the end of therapy (I(eot)). The I(eot) indices were lower in sustained virological responders than in relapsers (RELs) and nonresponders (NRs) (median values: 31 vs. 2,190 vs. 1,090,000; P < 0.001), and were independently associated with treatment outcomes (P = 0.003). A threshold of 250 I(eot) was shown to identify sustained virological response (SVR) with high positive predictive value (93%) and good diagnostic accuracy (81%). The time taken to attain 250 I(eot) ranged from 3 to 11 months in patients with hepatitis C virus (HCV) genotypes 2 or 3 and from 3 to 18 months in those with HCV genotypes 1 or 4. Overall, the duration of therapy would have been 49 months less than that suggested by the most recent algorithms based on a rapid virological response (RVR) at week 4.

Accordion Index: A new tool for the prediction of the efficacy of peg-interferon-alpha-2b and ribavirin combination therapy for chronic hepatitis C

AIM

An optimal treatment regimen based on individual virological response is essential to maximize the efficiency of interferon (IFN) therapy for chronic hepatitis C.

METHODS

Using indicators of the virological response and the treatment intensity, we developed the Accordion Index as a new tool for the efficacy prediction of peg-IFN and ribavirin (RBV) combination therapy. For the Accordion Index, the IFN-AC ratio and RBV-AC ratio were defined as follows: IFN-AC ratio = (total IFN dose given during the entire treatment period)/(total IFN dose required to achieve hepatitis C virus [HCV]-RNA negativity), RBV-AC ratio = (total RBV dose given during the entire treatment period)/(total RBV dose required to achieve HCV-RNA negativity).

RESULTS

The analysis of the association between the Accordion Index and the sustained virological response (SVR)revealed that of 25 patients who had HCV-RNA negativity during treatment, all 10 patients with an IFN-AC ratio and RBV-AC ratio of at least 4.0 achieved SVR, while only four of 15 patients with an IFN-AC ratio or RBV-AC ratio of less than 4.0 achieved SVR. With the cut-off value for both the IFN-AC ratio and RBV-AC ratio at 4.0 or higher, the quality of SVR prediction was as follows: the positive predictive value was 100%, the negative predictive value was 73.3%, and accuracy was 84.0%.

CONCLUSION

The Accordion Index will thus be a useful tool for planning optimal treatment regimens for individual patients.

Rapid virologic response: a new milestone in the management of chronic hepatitis C

BACKGROUND

Rapid virologic response (RVR), defined as an undetectable serum hepatitis C virus (HCV) RNA level at week 4 of treatment, is emerging as an important milestone in the treatment of patients who have chronic hepatitis C by use of pegylated interferon-alfa and ribavirin--the current standard of care. This assessment is being used to individualize treatment duration, which is currently recommended as 48 weeks in patients infected with HCV genotype 1 (G1) and 24 weeks in those infected with HCV G2 or G3.

METHODS

We collated information from studies including assessment of HCV RNA level at week 4, specifically highlighting the relationship between RVR and other predictors of treatment outcome and the manner in which RVR can be used to optimize treatment outcomes for specific patient groups.

RESULTS

The role of RVR in the treatment of patients with chronic hepatitis C varies according to viral genotype. Among patients with HCV G2/G3 infection, several studies have shown that shortening the treatment duration to 12-16 weeks is effective among those who attain RVR. In contrast, RVR may be used as an indicator for both shortened and extended treatment durations among patients with HCV G1 infection. HCV G1-infected patients with low baseline viral load who attain RVR may be effectively treated for 24 weeks, whereas patients who do not attain RVR may be candidates for an extended 72-week regimen.

CONCLUSIONS

RVR is rapidly becoming a new tool for predicting treatment outcomes in patients with chronic hepatitis C and represents a key opportunity to individualize therapy according to treatment-related viral kinetics.

Albinterferon alpha-2b: a genetic fusion protein for the treatment of chronic hepatitis C

Treatment regimens based on the use of interferon-alpha (IFN-alpha) remain the cornerstone of therapy for chronic hepatitis C virus infection, which affects nearly 170 million people worldwide. Treatment options include unmodified IFN-alpha given three times weekly or pegylated IFNs given once weekly. The albumin-fusion platform takes advantage of the long half-life of human albumin to provide a new treatment approach that allows the dosing frequency of IFN-alpha to be reduced in individuals with chronic hepatitis C. Albinterferon alpha-2b (alb-IFN), a recombinant polypeptide composed of IFN-alpha2b genetically fused to human albumin, has an extended half-life and early evidence indicates that it is efficacious and well tolerated. Pharmacodynamic modeling supports treatment with alb-IFN at 2- or 4-week intervals. Phase 3 registration trials are in progress. The albumin-fusion platform is currently being applied to other important bioactive peptides with short half-lives. These fusion proteins, which are at present in different phases of clinical development, might lead to improved therapies across a broad range of diseases.

Prediction of efficient virological response to pegylated interferon/ribavirin combination therapy by NS5A sequences of hepatitis C virus and anti-NS5A antibodies in pre-treatment sera

A considerable number of patients infected with Hepatitis C virus subtype 1b (HCV-1b) do not respond to pegylated interferon/ribavirin combination therapy. In this study we explored a useful factor(s) to predict treatment outcome. A total of 47 HCV-1b-infected patients were treated with pegylated interferon/ ribavirin for 48 weeks. Sera of the patients were examined for the entire NS5A sequence of the HCV genome, HCV RNA titers and anti-NS5A antibodies. According to their responses, the patients were divided into two groups, early viral responders who cleared the virus by week 16 (EVR[16w]) and those who did not (Non-EVR[16w]). The mean number of mutations in the V3 region (aa 2356 to 2379) or that in the V3 region plus its N-terminally flanking region, which we refer to as interferon/ribavirin resistancedetermining region (IRRDR; aa 2334 to 2379), of NS5A obtained from the pretreatment sera was signifi-cantly larger for EVR(16w) compared with Non-EVR(16w). Moreover, HCV-1b isolates with > or =5 mutations in V3 or those with > or =6 mutations in IRRDR were almost exclusively found in EVR(16w). Also, the presence of detectable levels of anti-NS5A antibodies in the pretreatment sera was closely associated with EVR(16w). In conclusion, a high degree of sequence variation in V3 (> or =5) or IRRDR (> or =6) and the presence of detectable levels of anti-NS5A antibodies in the pretreatment sera would be useful factors to predict EVR(16w). On the other hand, a less diverse sequence in V3 (< or =4) or IRRDR (< or =5) together with the absence of detectable anti-NS5A antibodies could be a predictive factor for Non-EVR(16w).

Undetectable hepatitis C virus RNA at week 4 as predictor of sustained virological response in HIV patients with chronic hepatitis C

BACKGROUND

Low baseline serum hepatitis C virus (HCV)-RNA and clearance of viraemia at week 4 with pegylated interferon (pegIFN) plus ribavirin therapy predict sustained virological response (SVR) and enable a shorter duration of therapy in patients with chronic hepatitis C. It is unclear whether this applies to HIV/HCV-co-infected patients.

PATIENTS AND METHODS

In the Peginterferon Ribavirin ESpaña COinfection (PRESCO) trial, 389 co-infected patients received pegIFN-alpha2a 180 microg/week plus ribavirin 1000-1200 mg/day. Patients with HCV-2/3 were treated for 6 or 12 months, whereas patients with HCV-1/4 were treated for 12 or 18 months. For each genotype, baseline HCV-RNA and rapid virological response (RVR), defined as under 50 IU/ml HCV-RNA at week 4, were evaluated as predictors of SVR in an 'on-treatment' analysis.

RESULTS

Overall, SVR was achieved by 193 patients (49.6%), 68/191 (35.6%) with genotype 1, 110/152 (72.4%) with genotypes 2/3 and 15/46 (32.6%) with genotype 4. RVR was the best predictor of SVR regardless of HCV genotype. Only for HCV-1 patients, baseline HCV-RNA less than 500 000 IU/ml was also associated with SVR. In HCV-3 patients RVR had a positive predictive value (PPV) for SVR of 90%, with treatment for 24 or 48 weeks. The PPV of SVR for patients with RVR was 69% for HCV-1 and 83% for HCV-4.

CONCLUSION

Undetectable HCV-RNA at week 4 is the best predictor of curing chronic hepatitis C in HCV/HIV-co-infected patients. In HCV-1 patients, baseline HCV-RNA also predicts response. HIV patients with HCV-3 and RVR may permit shortening therapy duration to only 24 weeks of pegIFN plus 1000-1200 mg ribavirin.

Assessment of hepatitis C virus-RNA clearance under combination therapy for hepatitis C virus genotype 1: performance of the transcription-mediated amplification assay

Monitoring of HCV-RNA in blood during antiviral therapy is performed mostly by commercially available reverse transcription polymerase chain reaction-based (RT-PCR) assays, with a lower detection limit of 30-50 IU/mL of HCV-RNA. Use of different tests in the pivotal trials of combination therapy has generated some discordance, in terms of predictive value of the early virological response (EVR). To evaluate whether the use of a more sensitive test, as a qualitative assay based on transcription mediated amplification (TMA) with a lower detection limit of 5-10 IU/mL of HCV-RNA, may obtain a better prediction of EVR and of the ultimate virological outcome, we retrospectively evaluated serial samples from 108 naïve patients with HCV genotype 1 chronic hepatitis, treated with pegylated alpha2b interferon plus ribavirin for 48 weeks and with a 24 weeks stopping rule. Serum samples of patients, obtained during treatment at weeks 4, 12, 24 and 48 and after treatment at week 24, were evaluated by TMA. Comparison of the RT-PCR and TMA assays for the qualitative detection of HCV-RNA showed no significant differences in performance when these tests were used at the end of the treatment period for assessing patients without an on-treatment virological response and those who eventually obtain a sustained virological response. Our results show instead that the use of TMA assay to detect HCV-RNA at 12 and 24 weeks of the combination therapy is more effective than RT-PCR in identifying patients with the highest probability of sustained HCV-RNA clearance.

Individualized treatment duration for hepatitis C genotype 1 patients: A randomized controlled trial

It was hypothesized that in hepatitis C virus (HCV) genotype 1 patients, variable treatment duration individualized by first undetectable HCV RNA is as effective as standard 48-week treatment. Patients (n = 696) received peginterferon alfa-2a, 180 mg/week, or peginterferon alfa-2b, 1.5 mg/kg/week, plus ribavirin, 1000-1200 mg/day, for 48 weeks (standard, n = 237) or for 24, 48, or 72 weeks if HCV-RNA-negative at weeks 4, 8, or 12, respectively (variable, n = 459). Sustained virologic response (SVR) was achieved in 45.1% [95% confidence interval (CI) 38.8-51.4] of the patients in the standard group and in 48.8% (CI 44.2-53.3) of the patients in the variable group (P = 0.37). The percentages of patients who first achieved undetectable HCV RNA at weeks 4, 8, or 12 were 26.7%, 27.8%, and 11.3%, respectively. In the standard treatment group, 87.1%, 70.3%, and 38.1% of patients who first achieved undetectable HCV RNA at 4, 8, or 12 weeks attained SVRs, respectively. In the variable group, corresponding SVR rates were 77.2%, 71.9%, and 63.5%. Low viremia levels and young age were independent predictors of response at week 4 [rapid virologic response (RVR)]. RVR patients with baseline viremia >or=400,000 IU/mL achieved higher SVR rates when treated for 48 weeks rather than 24 weeks (86.8% versus 73.1%, P = 0.14). The only predictive factor of SVR in RVR patients was advanced fibrosis.

CONCLUSION

Variable treatment duration ensures SVR rates similar to those of standard treatment duration, sparing unnecessary side effects and costs.

Recurrent hepatitis C after liver transplantation: on-treatment prediction of response to peginterferon/ribavirin therapy

Sustained virologic response (SVR) in the treatment of recurrent hepatitis C virus (HCV) infection after liver transplantation (LT) remains suboptimal. We evaluated efficacy of pegylated interferon alfa (PEG) and ribavirin (RBV) (PEG/RBV) combination therapy in LT recipients with recurrent HCV and predictive values of rapid virological response (RVR) and early virologic response (EVR). Between January 2001 and October 2005, LT recipients with recurrent HCV were intended to be treated for 48 weeks with PEG/RBV combination therapy independent of genotype or virologic response [53 patients (79% genotype 1)]. On-treatment predictor of response at week 4 (RVR) was defined as undetectable HCV RNA, and at week 12 (EVR) as undetectable HCV RNA or a >2 log(10) drop from pretreatment viral load. SVR was seen in 19 (35%) patients. Patients with genotype 2/3 were more likely to achieve SVR than those with genotype 1 (87% versus 23%; P = 0.001). The highest rate of SVR was seen in patients with RVR [specificity and positive predictive value (PPV) = 100%] while the highest rate of treatment failure was seen in those who did not have EVR [sensitivity and negative predictive value (NPV) = 100%]. The NPV of RVR to identify those who will not achieve SVR was also very high (88%). EVR had low PPV (63%) to identify those with SVR. In conclusion, PEG/RBV combination therapy is effective in the treatment of post-LT recurrent HCV. On-treatment virologic monitoring is highly predictive of SVR and may optimize the virologic response and minimize toxicity. Given its high PPV and NPV, RVR appears to be the most appropriate decision time point for continuation of therapy.

Optimizing outcomes in patients with hepatitis C virus genotype 1 or 4

Currently, many decisions for the treatment of hepatitis C virus (HCV) are based on genotype, which is the most significant baseline predictor of response to therapy; however, it has become increasingly apparent that fixed treatment durations might not be appropriate for all patients. The use of on-treatment predictors such as rapid virological response (RVR) at week 4 and early virological response (EVR) at week 12 can be used to predict the likelihood of achieving a sustained virological response (SVR), helping to tailor treatment to the individual. Until now, EVR has been defined as achieving either undetectable HCV RNA (<50 IU/ml) or a >2 log drop in HCV RNA, but still detectable, at week 12. However, rates of SVR in patients achieving an EVR are heterogeneous. It has recently been suggested that by subdividing EVR into RVR (<50 IU/ml at week 4), complete EVR (HCV RNA <50 IU/ml at week 12) or partial EVR (HCV RNA >2 log drop in HCV RNA but still detectable [>50 IU/ml] at week 12), it might be possible to further improve the prediction of patients likely to achieve an SVR and may allow for tailoring of treatment duration. Genotype 1 and 4 patients achieving an RVR have high rates of SVR and may be candidates for shorter treatment duration. Patients with a complete EVR achieve high SVR rates with the current treatment duration of 48 weeks, whereas patients achieving a partial EVR have lower rates of SVR and could benefit from treatment intensification to 72 weeks. Here, we discuss the importance of baseline predictors of response and the emerging concept of response-guided therapy in genotype 1 and 4 patients.

Suitable treatment period in patients with virological response during combination therapy of peginterferon and ribavirin for chronic hepatitis C

OBJECTIVE

The aim of this study was to determine the suitable treatment period in patients who achieve virological response during combination therapy of peginterferon and ribavirin for chronic hepatitis C virus infection.

METHODS

Inclusion criteria were HCV-genotype 1b, serum HCV RNA level of > or =100 KIU/ml before treatment, and negativity of serum HCV RNA during treatment. The 366 patients were enrolled in this retrospective cohort study. Patients were classified into four groups according to difference of response: rapid-virological response (RVR) at week 4 after the initiation of treatment (n=37), early-virological response (EVR) at week 5-12 (n=161), late-virological response (LVR) at week 13-24 (n=131), and superlate-virological response (SLVR) at week 25-48 (n=37). A non-relapse in patients with undetectable HCV RNA during therapy was defined as clearance of HCV RNA 6 month after the cessation of therapy.

RESULTS

Of the 366 patients, 241 had non-relapse and the non-relapse rate in each group was 89% (33/37) in RVR, 79% (127/161) in EVR, 54% (71/131) in LVR, and 27% (10/37) in SLVR. In RVR, 26 of 27 patients with continuance of negative HCV RNA of > or =30 weeks during treatment had non-relapse. In EVR, patients with period of negative HCV RNA of > or =40 weeks had non-relapse rate of 90% (71/79). In LVR and SLVR, all nine patients with continuance of negative HCV RNA of > or =60 weeks had non-relapse.

CONCLUSION

A suitable treatment period of combination therapy for chronic hepatitis C should be determined based on the time of attainment of negative HCV RNA.

3D QSAR and molecular docking studies of benzimidazole derivatives as hepatitis C virus NS5B polymerase inhibitors

The urgent need for novel HCV antiviral agents has provided an impetus for understanding the structural requisites of NS5B polymerase inhibitors at the molecular level. Toward this objective, comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) of 67 HCV NS5B polymerase inhibitors were performed using two methods. First, ligand-based 3D QSAR studies were performed based on the lowest energy conformations employing the atom fit alignment method. Second, receptor-based 3D QSAR models were derived from the predicted binding conformations obtained by docking all NS5B inhibitors at the allosteric binding site of NS5B (PDB ID: 2dxs). Results generated from the ligand-based model were found superior (r2cv values of 0.630 for CoMFA and 0.668 for CoMSIA) to those obtained by the receptor-based model (r2cv values of 0.536 and 0.561 for CoMFA and CoMSIA, respectively). The predictive ability of the models was validated using a structurally diversified test set of 22 compounds that had not been included in a preliminary training set of 45 compounds. The predictive r2 values for the ligand-based CoMFA and CoMSIA models were 0.734 and 0.800, respectively, while the corresponding predictive r2 values for the receptor-based CoMFA and CoMSIA models were 0.538 and 0.639, respectively. The greater potency of the tryptophan derivatives over that of the tyrosine derivatives was interpreted based on CoMFA steric and electrostatic contour maps. The CoMSIA results revealed that for a NS5B inhibitor to have appreciable inhibitory activity it requires hydrogen bond donor and acceptor groups at the 5-position of the indole ring and an R substituent at the chiral carbon, respectively. Interpretation of the CoMFA and CoMSIA contour maps in context of the topology of the allosteric binding site of NS5B provided insight into NS5B-inhibitor interactions. Taken together, the present 3D QSAR models were found to accurately predict the HCV NS5B polymerase inhibitory activity of structurally diverse test set compounds and to yield reliable clues for further optimization of the benzimidazole derivatives in the data set.

Treatment extension to 72 weeks of peginterferon and ribavirin in hepatitis c genotype 1-infected slow responders

In hepatitis C virus (HCV) genotype 1 infection, the duration of interferon-based therapy is a critical determinant in achieving sustained virologic response (SVR). Slow or late responders to peginterferon and ribavirin may benefit from an extended treatment course. We sought to determine if therapy extension could improve response rates in a United States population of slow responders. Slow response was defined by achieving at least a 2-log decrement in HCV RNA from baseline, yet having detectable HCV RNA at 12 weeks and undetectable HCV RNA at 24 weeks (polymerase chain reaction, TaqMan, Roche; detection limit 10 IU/mL). Patients were treatment-naïve, chronically infected genotype 1-infected slow responders to 1.5 mug/kg/week of peginterferon-alpha2b and 800-1400 mg/day of ribavirin and were randomly assigned 1:1 to complete a total of 48 or 72 weeks of therapy. Dose reductions and treatment discontinuations for adverse events or laboratory abnormalities were similar between the 2 treatment arms. End-of-treatment response rates were similar in the 72-week group compared with those in the 48-week group (48% versus 45%; P value not significant). Overall, the rate of SVR was superior in patients treated for 72 weeks versus 48 weeks (38% versus 18%, respectively; P = 0.026).

CONCLUSION

Extending the treatment duration from 48 weeks to 72 weeks in genotype 1-infected patients with slow virologic response to peginterferon-alpha2b and weight-based ribavirin significantly improves SVR rates. Treatment extension does not seem to increase the rate of dose reduction or therapy discontinuation.

Managing chronic hepatitis C in the difficult-to-treat patient

Patients with chronic hepatitis C virus (HCV) infection and disease-related complications - among them cirrhosis and liver failure - pose a particular management challenge. Some of these patients may fail to respond to current therapy (non-responders), and some are affected so severely that treatment puts them at an unacceptable risk for complications. Treatment with pegylated interferon (peg-IFN) plus ribavirin improves hepatic enzyme levels and eradicates the virus in approximately 50% of patients; however, a significant number of patients do not respond to therapy or relapse following treatment discontinuation. Several viral, hepatic and patient-related factors influence response to IFN therapy; many of these factors cannot be modified to improve long-term outcomes. Identifying risk factors and measuring viral load early in the treatment can help to predict response to IFN therapy and determine the need to modify or discontinue treatment. Retreatment options for patients who have failed therapy are limited. Retreatment with peg-IFN has been successful in some patients who exhibit an inadequate response to conventional IFN treatment, particularly those who have relapsed. Consensus IFN, another option in treatment-resistant patients, has demonstrated efficacy in the retreatment of non-responders and relapsers. Although the optimal duration of retreatment and the benefits and safety of maintenance therapy have not been determined, an extended duration is likely needed. This article reviews the risk factors for HCV treatment resistance and discusses the assessment and management of difficult-to-treat patients.

Hepatitis C virus (HCV) infection: a systemic disease

Hepatitis C virus (HCV) infection is a global health problem, being the second most common chronic viral infection in the world with a global prevalence of about 3% (about 180 million people). HCV is both an hepatotropic and a lymphotropic virus; and chronic infection could cause, on one hand, chronic hepatitis, cirrhosis and hepatocellular carcinoma and on the other hand several extrahepatic diseases including, first, mixed cryoglobulinemia and lymphoma. The association between hepatic (hepatocellular carcinoma) and extrahepatic (lymphoma, thyroid cancer) malignancies has justified the inclusion of HCV among human cancer viruses. The pathogenesis of HCV-related sequelae (hepatic or extrahepatic) is not fully understood representing a challenge of prime importance in light of the optimization of clinico-therapeutic management of these patients. Combined treatment with pegylated interferon plus ribavirin is presently the first-line, gold standard treatment of most HCV-related diseases. However, mainly in the case of extrahepatic manifestations, a cautious approach to the patient, with a case to case accurate tailoring of therapy is frequently requested. The present review will outline the principal aspects of such HCV-induced systemic disease focusing on extrahepatic manifestations.

Early Monitoring of Ribavirin Serum Concentration is not Useful to Optimize Hepatitis C Virus treatment in HIV-Coinfected Patients

Background

Emerging data suggest that higher ribavirin (RBV) exposure could improve early hepatitis C virus (HCV) response. Furthermore, interindividual RBV bioavailability shows high variation, and dose-limiting haemolytic anaemia is a common adverse event. Therefore, it has been suggested that monitoring RBV serum levels could be used to drive dose modification and to optimize management of HCV-infected patients receiving combination treatment.

Methods

To assess the effect of RBV serum levels on HCV RNA clearance at week 4 and 12 of treatment, and to determine the correlation between RBV serum concentration and haemoglobin decrease, RBV trough levels were measured by HPLC in stored serum samples obtained from 94 HCV-HIV-coinfected patients at week 4 and 12 of treatment with peginterferon-α2b (1.5 μg/kg/weekly) plus ribavirin (800–1,200 mg/day).

Results

The median RBV levels increased from 1.70 μg/ml at week 4 to 1.97 μg/ml at week 12 of treatment ( P=0.001) and were independently predicted by weight-adjusted dose of RBV and co-administration of tenofovir. Haemoglobin drop was higher among patients who received zidovudine and weakly correlated with RBV level. Although RBV concentration was lower in genotype 1 or 4 HCV-infected patients who cleared the virus at treatment week 4, the ability of this parameter to discriminate between responders and non-responders at treatment week 4 and 12 was poor.

Conclusion

Intracellular RBV accumulation early in treatment might improve the kinetics of HCV response in difficult to treat patients. Although this hypothesis and the potential interaction between RBV and tenofovir warrant further research, our data do not support RBV serum monitoring as a tool to optimize treatment in HCV-HIV-coinfected patients.

[Ocular complications of hepatitis C treatment]

INTRODUCTION

Hepatitis C is a viral infection that can lead to hepatocellular carcinoma. According to current recommendations, the treatment is based on the association of pegylated interferon and ribavirin. Strict treatment criteria are available and apply for the 8,000 patients diagnosed every year in France. Ophthalmological side effects are numerous, unpredictable, and sometimes severe.

CASE REPORT

We report the case of a patient treated with an association of interferon and ribavirin for hepatitis C, who presented two periods of decreased visual acuity 4 years apart. Interferon-related toxic retinopathy was suggested for the first event, while optical neuropathy was diagnosed for the second.

CONCLUSION

Ocular complications of hepatitis C treatment with interferon and ribavirin are frequent but often benign. Our recommendations are periodic ophthalmological examinations, including visual acuity and fundus examination, before starting the treatment, at 3 months, and if necessary at 9 months.

Retreatment of chronic hepatitis C in previous non-responders and relapsers

Therapy for chronic hepatitis C has improved dramatically over the past 20 years. Unfortunately, approximately 50% of those treated do not have a durable response to therapy. Non-responders and relapsers after previous interferon-based therapy are particularly challenging with regard to clinical management. This article provides a general overview of the treatment of hepatitis C and reviews present data regarding management of patients with chronic hepatitis C who are non-responders or relapsers after previous treatment. The review ends with the authors' opinion regarding present management of non-responders and relapsers and future emerging therapies.

Interferon-based therapy of hepatitis C

In 2007, the world celebrated the 50th anniversary of the discovery of interferon (IFN). The first clinical trial of recombinant IFN-alpha in patients with chronic hepatitis C was published in 1986. This article reviews the classification of IFNs, IFN production during viral infections, IFN signaling pathways and the mechanisms of their antiviral and immunomodulatory properties. Hepatitis C virus infection treatment is currently based on the combination of pegylated IFN-alpha and ribavirin. The pegylated IFN-alpha molecules are described, as well as the putative mechanisms of action of ribavirin. Current treatment guidelines are discussed and new results suggesting that the treatment schedule should be tailored to the early virological response during therapy are presented. Finally, insights into new hepatitis C drug developments are given.

New drugs for hepatitis C virus

No new therapy has been approved for the treatment of chronic hepatitis C in the last 5 years in the USA since the approval of pegylated interferon (IFN)-alpha(2a) and ribavirin. Multiple new drugs are currently in development and are expected to be approved for use in the USA and/or the EU by 2011-2013. Although the mechanism of action of pegylated IFN and ribavirin are not completely known, it is likely that they will continue to be used in combination regimens for a number of years. Direct antivirals are likely to be the first new drugs to be used in combination with pegylated IFN and ribavirin. Viral resistance will prove to be a significant barrier and require that consolidation therapy with at least 24 weeks of pegylated IFN and ribavirin be used to successfully prevent the selection or emergence of resistant variants. Numerous other compounds, such as ribavirin analogs, long-acting IFNs, hepatoprotectants and immunomodulators, are in development and may replace the drugs that are used currently. The combination of direct antivirals, such as protease and polymerase inhibitors, may rapidly follow in development, as has occurred in HIV drug therapy.

Which patients with genotype 1 chronic hepatitis C can benefit from prolonged treatment with the 'accordion' regimen?

The on-treatment virological response to pegylated interferon plus ribavirin therapy is a useful tool in the management of patients with chronic hepatitis C. The time at which hepatitis C virus RNA becomes undetectable by a sensitive PCR assay has a huge impact on the probability of achieving a sustained virological response, particularly in genotype 1 patients, and may be useful in selecting patients for prolonged therapy. Indiscriminate extension of treatment in patients with hepatitis C virus genotype 1 is not beneficial. However, there is a subgroup of patients - the so-called 'slow responders' - who benefit from extending treatment from 48 to 72 weeks and can be readily identified after 4-12 weeks of combination therapy. Thus, it is important to distinguish slow responders from null responders. In the TeraVIC-4 study virological relapse rates were significantly lower, and sustained virological response rates were significantly higher, in those treated for 72 weeks with peginterferon alfa-2a (40 kDa) plus ribavirin (45% vs. 32% with 48 weeks, P=0.014). Patients are best served by quantitative determination of the hepatitis C virus RNA level at weeks 4, 12 and 24. The results of these determinations can then be used to tailor the length of therapy.

Sustained HCV-RNA response and hepatitis Bs seroconversion after individualized antiviral therapy with pegylated interferon alpha plus ribavirin and active vaccination in a hepatitis C virus/hepatitis B virus-coinfected patient

Hepatitis B virus (HBV) and hepatitis C virus (HCV) coinfection is frequently associated with progressive liver disease. Treatment options are limited and no data on the efficacy of pegylated interferon (PEG-IFN) plus ribavirin therapy are available. We report a case of a 49-year-old woman with chronic hepatitis B and C who was scheduled for a 48 weeks course of PEG-IFNalpha-2b plus ribavirin therapy. She had HCV genotype 2 infection and was negative for HBV-DNA and HBe antigen before treatment. Although the HCV-RNA response was rapid until week 12, hepatitis B surface antigen (HBsAg) levels showed a more linear decline. At week 48, HBsAg was still positive, however, with very low levels of only 0.06 IU/ml. Treatment was therefore continued for another 4 weeks combined with active HBV immunization until HBs seroconversion occurred. Forty-three weeks after treatment, the patient showed a robust HBs seroconversion (anti-HBs of 260 IU/ml) and a sustained HCV-RNA response. This case highlights that combination therapy of PEG-IFNalpha-2b with ribavirin of HBV/HCV-coinfected individuals cannot only induce a sustained HCV-RNA response but also HBsAg seroconversion in single patients. Monitoring of HBsAg levels can be useful in individualizing optimal treatment duration in HBV-infected patients.

Future Treatment of Chronic Hepatitis C

The current standard therapy for chronic hepatitis C is peginterferon plus ribavirin and yields a sustained virological response rate of approximately 50% overall. Over the past 2–3 years, many new therapeutic agents directed at a number of different viral targets have entered into development for the treatment of patients with chronic hepatitis C. Many of these agents exhibit high levels of potency against the hepatitis C virus and have a rapid onset of activity. Some agents have been abandoned because of lack of efficacy or toxicity, but many others have shown promise and are undergoing further testing. Although debated, new therapies in the immediate future will most likely be used in combination with peginterferon, either alone or with ribavirin. This concise review is focused on new drugs undergoing development for the treatment of patients with chronic hepatitis C, and on drugs that have shown efficacy in preliminary investigations and progressed to Phase II or III trials. This information should allow physicians involved in the care of patients with chronic hepatitis C to provide realistic expectations of what types of drugs are progressing in clinical development, the likelihood that new treatment will include peginterferon with or without ribavirin, and when these novel therapies might become available.

Early virologic response after peginterferon alpha-2a plus ribavirin or peginterferon alpha-2b plus ribavirin treatment in patients with chronic hepatitis C

Patients infected with hepatitis C virus (HCV) genotype 1 and with serum HCV RNA concentrations over 800 000 IU/mL have relatively low rates of virologic response to pegylated interferons. The 2 forms of pegylated interferon have different pharmacokinetic profiles, and pilot studies comparing them have yielded varying results. We compared the virologic response to 12 weeks of treatment with peginterferon alpha-2a plus ribavirin vs peginterferon alpha-2b plus ribavirin in 380 patients who were infected with HCV genotype 1 and had high viral loads. We observed no between-group differences in viral load reduction over time and no differences in the percentage of patients treated with peginterferon alpha-2a or peginterferon alpha-2b plus ribavirin who achieved early virologic response (EVR), defined as >/=2-log reduction in HCV RNA concentration or undetectable HCV RNA at 12 weeks (66%vs 63%). Serum levels of interferon were more frequently below the level of quantitation in patients treated with peginterferon alpha-2b plus ribavirin (58-68%) than in those treated with peginterferon alpha-2a plus ribavirin (1-2%). Patients treated with peginterferon alpha-2b plus ribavirin had higher rates of discontinuation for safety reasons (6%vs 1%). In conclusion, a substantial percentage of patients infected with HCV genotype 1 and high viral load can achieve EVR when treated with peginterferon and ribavirin. The 2 pegylated interferons showed comparable anti-HCV activity during the first 12 weeks of treatment when combined with the same doses of ribavirin (1000-1200 mg/day), but discontinuations for safety reasons were higher in the patients treated with peginterferon alpha-2b plus ribavirin.

Nanomedicines in the treatment of patients with hepatitis C co-infected with HIV--focus on pegylated interferon-alpha

In immuno-competent individuals, the natural course of chronic hepatitis C virus (HCV) infection is highly variable and 5%–30% of patients develop cirrhosis over 20 years. Co-infection with HCV and human immunodeficiency virus (HIV) is an important prognostic factor and associated with more frequent and accelerated progression to cirrhosis. Until recently HIV/AIDS-related complications were life limiting in patients co-infected with HCV; the introduction of highly active antiretroviral treatment (HAART) and the better prognosis of HIV infection has made HCV-related complications an emerging health problem in HCV/HIV co-infected individuals. Treatment of chronic HCV infection has also evolved since the introduction of interferon-alpha. Recently, introduction of pegylated interferon-alpha (peginterferon-alpha) has resulted in an increase in sustained virus clearance rates of up to 80% in selected genotypes and patient populations. The safety and efficacy of modern anti HCV treatment regimens – based on peginterferon-alpha in combination with ribavirin – was evaluated in 4 controlled trials. Sustained clearance of hepatitis C virus can be achieved in up to 35% of patients with HIV/HCV co-infection, and novel HCV treatment regimens based on peginterferon-alpha have no negative effect on the control of HIV disease. In conclusion, if HIV infection is well controlled and CD4⁺ cell counts >100/mm³, treatment of chronic hepatitis C with peginterferon in combination with ribavirin is safe and should be given for 48 weeks regardless of the HCV genotype. Introduction of peginterferon-alpha has significantly improved adherence to treatment and treatment efficacy; in particular sustained virologic response in patients with HCV genotype 1 or 4 infection improved, but sustained viral clearance in only 7%–38% of patients infected with genotype 1 and 4 cannot be the final step in development of effective treatments in patients with HCV/HIV co-infection.

Pegylated interferon therapy in chronic hepatitis C: lights and shadows of an innovative treatment

Pegylated interferon (PEG-IFN) in combination with ribavirin is the standard of treatment for chronic hepatitis C. Several viral and host factors influence the outcome of treatment, such as hepatitis C virus (HCV) genotype, baseline viral load, viral kinetics, race, body weight, advanced liver disease, HIV co-infection, and adherence to therapy. Monitoring the response of HCV to treatment during the early time points (4 weeks or 12 weeks) after initiation of therapy has emerged as a critical tool to predict sustained virologic response (SVR), defined as undetectable serum HCV RNA 24 weeks after the end of therapy. To counterbalance the influence of host and viral factors, treatment duration can be individualised to achieve an optimal treatment outcome, potentially reduce costs, and minimize side effects.

Role of weight-based ribavirin dosing and extended duration of therapy in chronic hepatitis C in HIV-infected patients: the PRESCO trial

The response to pegylated interferon (pegIFN) plus ribavirin (RBV) as treatment of chronic hepatitis C virus (HCV) infection is lower in HIV-coinfected than in HCV-monoinfected patients and could be due to suboptimal RBV dosing and/or insufficient duration of therapy in prior trials. In a prospective, multicenter, open, comparative trial, HCV/HIV-coinfected patients received pegIFN plus weight-based RBV for 48 or 72 weeks (HCV genotypes 1 and 4) and 24 or 48 weeks (HCV genotypes 2 and 3). Use of didanosine was not allowed. Out of 389 patients included in the trial, 61% were infected by HCV-1/4 and 67% had serum HCV-RNA >500,000 IU/ml. Sustained virological response (SVR) was achieved by 49.6%, significantly higher in HCV-2/3 than HCV-1/4 (72.4% vs. 35%; p < 0.0001). A high drop-out rate in the longer treatment arms precluded obtaining definitive conclusions about the efficacy of prolonging therapy. Premature treatment discontinuations due to serious adverse events occurred in 8.2%. Infection with HCV-2/3, lower baseline HCV-RNA, and negative HCV-RNA at week 12 were all independent predictors of SVR in the multivariate analysis. The use of RBV 1000-1200 mg/day plus pegIFN is relatively safe and provides SVR in nearly half of coinfected patients, twice as high in HCV-2/3 than HCV-1/4.

Defining Optimal Therapeutic Outcomes in Chronic Hepatitis

The definition of optimal therapeutic response has been evolving concurrent with the advancement of diagnostic tests. What once was considered "therapeutic success" is considered now disease persistence or relapse. As the laboratory tools become increasingly sensitive, it follows that the criteria of successful therapeutic response are becoming more stringent. The main objectives of chronic hepatitis B and C treatment are to achieve eradication of the virus and, with this, reduction or prevention of hepatic injury and disease progression. However, in the case of hepatitis B, viral suppression is for the moment a more realistic therapeutic objective, although eradication still remains the ultimate goal. In chronic hepatitis C, sustained virologic response, defined as the absence of HCV RNA 6 months post-antiviral treatment completion, is within reach. Better test sensitivity allows for additional levels of confidence in the achievements of virus eradication in patients with hepatitis C. Challenges persist despite great advances in the treatment of chronic viral hepatitis. Now that clearer therapeutic outcomes have been refined, more efficacious, and better-tolerated drugs may change the current therapeutic landscape of chronic viral hepatitis B and C.

Current and Future Hepatitis C Therapies

Treatment of chronic hepatitis C patients has evolved significantly in the past 15 years. With a better knowledge of viral kinetics and molecular virology of the hepatitis C virus, we have gone from a low chance of viral eradication to a chance as high as 50%. Despite this, current therapies are not ideal and are associated with side effects, complications, and poor patient tolerability. Therefore, an urgent need to look for better strategies to treat this disease is imperative. Thanks to the current knowledge and ongoing research, we know the way we treat hepatitis C today will change dramatically in the next 5-10 years. This review will focus on current therapies for hepatitis C and the most recent advances in the search for new therapies.

Baseline factors prognostic of sustained virological response in patients with HIV-hepatitis C virus co-infection

OBJECTIVE

To identify baseline characteristics predictive of a sustained virological response (SVR) in patients with HIV-hepatitis C virus (HCV) co-infection treated with interferon-based therapy.

DESIGN/METHODS

A stepwise multiple logistic regression analysis was used to explore the prognostic factors associated with SVR [undetectable HCV-RNA (< 50 IU/ml) at the end of untreated follow-up in week 72].

RESULTS

In all patients (n = 853), in addition to the HCV therapy received, the factors most predictive of SVR were baseline HCV-RNA [< or = versus > 400 000 IU/ml; odds ratio (OR) 4.77; 95% confidence interval (CI) 3.15-7.22; P < 0.0001] and HCV genotype (OR 2.87; 95% CI 2.00-4.12; P < 0.0001). HIV treatment (with a protease inhibitor or non-nucleoside reverse transcriptase inhibitor; P = 0.034), race (P = 0.027), and body mass index (P = 0.039) were also weak predictors of HCV treatment response.

CONCLUSIONS

In the AIDS PEGASYS Ribavirin International Co-infection Trial (APRICOT), the predictors of SVR among HIV-HCV co-infected patients treated with peginterferon alfa-2a plus ribavirin were similar to those in patients with HCV mono-infection. The HCV genotype and pretreatment HCV-RNA level had the greatest influence on SVR.

Early ribavirin pharmacokinetics, HCV RNA and alanine aminotransferase kinetics in HIV/HCV co-infected patients during treatment with pegylated interferon and ribavirin

BACKGROUND/AIMS

We evaluated whether early ribavirin pharmacokinetics differ comparing hepatitis C/human immunodeficiency virus coinfected sustained virological responders and nonresponders.

METHODS

Twenty-four treatment-naive coinfected patients received pegylated-interferon alfa-2b (12 kDa) (1.5 microg/kg) once weekly plus daily ribavirin (13.6 mg/kg/d) for up to 48 weeks. Serum HCV RNA, serum alanine aminotransferase, and plasma ribavirin levels were measured frequently during the first 16 days of therapy and monthly thereafter.

RESULTS

Six patients were sustained responders. During the first 4 weeks of treatment, median plasma ribavirin levels and area under the ribavirin curve were significantly lower (p<0.0001 and p<0.01, respectively) in sustained responders compared with nonresponders. Compared to ribavirin levels at weeks 2 and 4, ribavirin levels in sustained responders continued to increase significantly until week 8 (p<0.02). At week 4, hemoglobin declines were significantly (p=0.002) greater in sustained responders than nonresponders. At week 1, serum HCV RNA levels and changes in alanine aminotransferase levels relative to baseline could identify likely responders better than plasma ribavirin levels.

CONCLUSIONS

We conjecture that intracellular ribavirin accumulation may be enhanced early in treatment in coinfected sustained responders, although this hypothesis should be investigated further. At week 1, serum HCV RNA and changes in alanine aminotransferase levels relative to baseline might identify likely responders.

Overestimation and underestimation of hepatitis C virus RNA levels in a widely used real-time polymerase chain reaction-based method

The quantification of hepatitis C virus (HCV) RNA is essential for the everyday management of chronic hepatitis C therapy. Real-time polymerase chain reaction (PCR) techniques are potentially more sensitive than classical PCR techniques, are not prone to carryover contamination, and have a consistently wider dynamic range of quantification. Thus, they are rapidly replacing other technologies for the routine quantification of HCV RNA. We extensively evaluated the intrinsic characteristics and clinical performance of Cobas Ampliprep/Cobas TaqMan (CAP/CTM), the most widely used real-time PCR assay for HCV RNA quantification. This study shows that CAP/CTM is sensitive, specific, precise, and reproducible and has a broad dynamic range of quantification well suited to HCV RNA monitoring in clinical practice. However, we identified 2 technical issues that will have an impact in clinical practice. First, the CAP/CTM assay overestimates HCV RNA levels in undiluted patient samples by approximately 0.6 log(10) international units per milliliter on average, and this overestimation increases with the viral load. Second, the CAP/CTM assay substantially underestimates HCV RNA levels in approximately 15% of genotype 2 samples and 30% of genotype 4 samples, probably because of mismatches with the target sequences due to the primer and/or probe design.

CONCLUSION

As the CAP/CTM platform is widely available, easy to use, and suited to high-throughput screening for viral genomes, the manufacturer should improve the HCV RNA kit to resolve these 2 important technical issues that may affect everyday management of hepatitis C therapy.