Viral load a major factor affecting risk of sexually transmitting HIV

Public release date: 12-Jan-2012

Contact: John Heys
jheys@idsociety.org
703-299-0412
Infectious Diseases Society of America

Study also confirms condom use significantly reduces risk of HIV infection

The level of HIV-1 in the blood of an HIV-infected partner is the single most important factor influencing risk of sexual transmission to an uninfected partner, according to a multinational study of heterosexual couples in sub-Saharan Africa. The study, published in the Journal of Infectious Diseases, calculated the risk of HIV-1 transmission per act of sexual intercourse and found the average rate of infection to be about 1 per 900 coital acts. The findings also confirmed that condoms are highly protective and reduce HIV infectivity by 78 percent.

James P. Hughes, PhD, and colleagues at the University of Washington and the Fred Hutchinson Cancer Research Center, in Seattle; the University of Witwatersrand in South Africa; the University of Nairobi and Kenyatta National Hospital, in Kenya; and the Rwanda-Zambia HIV Research Group conducted a study that included 3,297 HIV-discordant couples (where one person is HIV-infected, and the other is not) in eastern and southern Africa who were enrolled in a randomized trial of acyclovir suppressive therapy. The couples had frequent follow-up to measure plasma HIV-1 RNA in the infected partner and genetic testing to link the transmitted virus to the index HIV-infected partner, to prevent inclusion of infections acquired from other possible partners. HIV acquisition was not affected by the acyclovir therapy.

The study confirmed that condoms are highly protective, reducing the risk of HIV transmission by 78 percent when subjects reported using a condom. Most important, the authors noted, was the level of HIV-1 RNA in the blood of the infected partner. The higher the viral load in the index infected partner, the higher the risk of transmission, emphasizing the importance of lowering viral load to help prevent the spread of HIV-1 through sex. Older age was associated with reduced transmission per sex act, and male circumcision reduced female-to-male transmission by approximately 47 percent. Genital herpes infections and the presence of genital ulcers were associated with increased rates of transmission.

"Our results underscore the importance of antiretroviral therapy, and, possibly, treatment of co-infections, to reduce plasma HIV-1 viral load in HIV-1 infected partners, and condom promotion, male circumcision, and treatment of symptomatic sexually-transmitted infections for HIV-1 uninfected partners as potential interventions to reduce HIV-1 transmission," the authors wrote.

The findings also showed that the risk of an HIV-infected man transmitting an infection to a woman not infected with HIV was about twice the risk of an HIV-infected woman transmitting to an HIV-uninfected man. However, this difference can be attributed to the difference in viral loads between men and women, the authors noted. On average, HIV-infected men have higher HIV-1 loads. Difference in age and having genital herpes in the HIV-uninfected partners also help account for the disparity—the HIV-uninfected female partners were, on average, younger and had higher rates of genital herpes than their male counterparts.

Previous studies examining HIV-1 per-act infectivity have been significantly smaller and not as comprehensive in terms of measuring plasma HIV-1 RNA and the use of genetic linkage of transmissions. In an editorial commentary, Ronald H. Gray, MD, and Maria J. Wawer, MD, both of Johns Hopkins University in Baltimore, noted that Dr. Hughes and his colleagues have possibly recorded the most precise estimates of HIV-1 transmission per sexual act during latent HIV disease, providing a valuable addition to knowledge in this area, where much remains to be learned.

Additional research using the genetic data collected from this study, in addition to new data from another recently completed clinical trial, is planned to help explain the variation in transmission risk among couples, the authors noted.

Fast Facts:

1. In HIV-discordant couples—where one partner is infected with HIV, and the other is not—viral load of the infected partner was a major factor affecting the HIV transmission rate.

2. Condom use among HIV-discordant couples was 78 percent effective in preventing transmission to the uninfected partner.

3. Factors such as age, male circumcision status, and sexually transmitted infections also affected transmission probability.

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Published continuously since 1904, the Journal of Infectious Diseases is the premier global journal for original research on infectious diseases. The editors welcome major articles and brief reports describing research results on microbiology, immunology, epidemiology, and related disciplines, on the pathogenesis, diagnosis, and treatment of infectious diseases; on the microbes that cause them; and on disorders of host immune responses. The journal is an official publication of the Infectious Diseases Society of America (IDSA). Based in Arlington, Va., IDSA is a professional society representing more than 9,000 physicians and scientists who specialize in infectious diseases. For more information, visit http://www.idsociety.org.

Source

Vitamin D supplementation improves sustained virologic response in chronic hepatitis C (genotype 1)-naïve patients

World J Gastroenterol. 2011 December 21; 17(47): 5184–5190.

Published online 2011 December 21. doi: 10.3748/wjg.v17.i47.5184

PMCID: PMC3243885

Copyright ©2011 Baishideng Publishing Group Co., Limited. All rights reserved.

Saif Abu-Mouch, Zvi Fireman, Jacob Jarchovsky, Abdel-Rauf Zeina, and Nimer Assy

Saif Abu-Mouch, Liver Unit, Department of Internal Medicine B, Hillel Yaffe Medical Center, Hadera 38100, Israel

Zvi Fireman, Jacob Jarchovsky, Department of Gastroenterology, Hillel Yaffe Medical Center, Hadera 38100, Israel

Abdel-Rauf Zeina, Liver Unit, Hillel Yaffe Medical Center, Hadera 38100, Israel

Nimer Assy, Liver Unit, Ziv Medical Center, Technion Institute, Safed 13100, Israel

Author contributions: Abu-Mouch S and Assy N wrote the paper and contributed equally to this work; Fireman Z and Jarchovsky J participated in study design; Zeina AR participated in the discussion.

Correspondence to: Saif Abu-Mouch, MD, Liver Unit, Department of Internal Medicine B, Hillel Yaffe Medical Center, POB 169, Hadera 38100, Israel. saif@hy.health.gov.il

Telephone: +972-4-3044110 Fax: +972-4-6304408

Received February 14, 2011; Revised March 27, 2011; Accepted April 3, 2011.

Abstract

AIM: To determine whether adding vitamin D, a potent immunomodulator, improves the hepatitis C virus (HCV) response to antiviral therapy.

METHODS: Seventy-two consecutive patients with chronic HCV genotype 1 were randomized into two groups: the treatment group (n = 36, 50% male, mean age 47 ± 11 years) received Peg-α-2b interferon (1.5 μg/kg per week) plus ribavirin (1000-1200 mg/d) together with vitamin D3 (2000 IU/d, target serum level > 32 ng/mL), and the control group (n = 36, 60% male, mean age 49 ± 7 years) received identical therapy without vitamin D. HCV-RNA was assessed by real-time polymerase chain reaction (sensitivity, 10 IU/mL). The sustained virologic response (SVR) was defined as undetectable HCV-RNA at 24 wk post-treatment.

RESULTS: Clinical characteristics were similar in both groups. The treatment group had a higher mean body mass index (27 ± 4 kg/m² vs 24 ± 3 kg/m²; P < 0.01), viral load (50% vs 42%, P < 0.01), and fibrosis score (> F2: 42% vs 19%, P < 0.001) than the controls. At week 4, 16 (44%) treated patients and 6 (17%) controls were HCV-RNA negative (P < 0.001). At week 12, 34 (94%) treated patients and 17 (48%) controls were HCV-RNA negative (P < 0.001). At 24 wk post-treatment (SVR), 31 (86%) treated patients and 15 (42%) controls were HCV-RNA negative (P < 0.001). Viral load, advanced fibrosis and vitamin D supplementation were strongly and independently associated with SVR (multivariate analysis). Adverse events were mild and typical of Peg-α-2b/ribavirin.

CONCLUSION: Adding vitamin D to conventional Peg-α-2b/ribavirin therapy for treatment-naïve patients with chronic HCV genotype 1 infection significantly improves the viral response.

Keywords: Hepatitis C, Vitamin D, Sustained viral response, Genotype 1, Fibrosis

INTRODUCTION

The current treatment for hepatitis C virus (HCV) infection is pegylated interferon α combined with ribavirin (Peg/RBV) administered for 24 wk for HCV genotypes 2 or 3, or 48 wk for HCV genotype 1, the most prevalent genotype in Israel, Europe, and North America[¹]. The aim of HCV therapy is a sustained virologic response (SVR), defined as an undetectable serum HCV-RNA level at 24 wk after the cessation of therapy. For patients with HCV genotype 1, the rate of SVR ranges between 38% and 46%[^2,3]. In subgroups of this population (e.g., Hispanics and African-Americans), the rate of SVR is even lower, reaching only 19%[⁴]. These differences are not explained by baseline viral load or compliance to treatment. Recent efforts to improve patient outcomes have focused on adding new antiviral therapies specifically targeted to HCV, including inhibitors of either HCV polymerase or protease[⁵]. However, few studies have addressed the issue of improving the host factors.

Vitamin D is a potent immunomodulator[^6,7]. Increased production of 1, 25-dihydroxy vitamin D3 results in the synthesis of cathelicidin, a peptide capable of destroying many viral infectious agents as well as M. tuberculosis. Low serum levels of 25-hydroxyvitamin D (< 20 ng/mL) prevent macrophages from initiating this innate immune response, which may explain why African-Americans, who are often vitamin D deficient, are more prone to contracting tuberculosis and viral infections than Caucasians[⁸]. Moreover, vitamin D improves insulin sensitivity[⁹], su-ppresses proinflammatory cytokines, increases anti-inflammatory cytokines, and improves CD4 T cell hyper-responsiveness[¹⁰]. Vitamin D deficiency is very common (92%) among patients with chronic liver disease, and at least one-third suffer from severe vitamin D deficiency (< 12 ng/mL)[¹¹]. Israeli subjects from various ethnic backgrounds are at higher risk of vitamin D deficiency[¹²]. Pettas and co-workers recently showed a low serum vitamin D level to be related to severe fibrosis and low responsiveness to interferon-based therapy in genotype 1 chronic hepatitis C (CHC)[¹³]. Its role and relationship to SVR and therapy in CHC are unknown. We reasoned that adding vitamin D to conventional therapy could improve treatment efficacy at weeks 4 [rapid viral response (RVR)] and 12 [early viral response (EVR)] during therapy, and 24 wk after cessation of therapy (SVR).

MATERIALS AND METHODS

Subjects

Study inclusion criteria were age 18-65 years, a chronic HCV genotype 1 infection, no previous treatment for hepatitis C, seronegative for HBV, HDV, and human immunodeficiency virus infections, an absolute neutrophil count of > 1500 per mm³, a platelet count of > 90 000 per mm³, and a normal hemoglobin level. Liver biopsies were required within 2 years prior to study entry, and the samples were examined by two pathologists who were unaware of patient identity and treatment regimen. The severity of hepatic inflammation and fibrosis was evaluated by the Ishak score in separate reports for grading and staging[¹⁴]. Exclusion criteria were decompensated liver disease (cirrhosis with a Child-Pugh score > 9), another cause of clinically significant liver disease, or the presence of hepatocellular carcinoma.

Study design

This was an intention-to-treat prospective randomized study. The experimental procedures were approved by the institutional review boards of the two participating medical centers. Informed consent was obtained from all participants (Clinical Trial Gov: NCT00804752)

The study included 72 consecutive CHC genotype 1 treatment-naïve patients who were stratified according to ethnic group (i.e., Russian/Jewish/Arab) due to possible differences in vitamin D levels. They were randomly assigned to one of two study groups. The treatment group comprising 36 patients (mean age 47 ± 11 years, 50% male) who received pegylated (peg)-interferon-α-2b (1.5 μg per kg body weight) plus oral ribavirin 1000 mg/d (for body weight < 75 kg) or 1200 mg/d (for body weight > 75 kg) and vitamin D3 (Vitamidyne D, Fischer Pharmaceuticals, Israel) 2000 IU/d, target serum level > 32 ng/mL) for 48 wk. Vitamin D3 was given by oral drops for 4 wk before the initiation of antiviral treatment and after serum levels had reached > 32 ng/mL in all patients in the treatment group. The supplemented vitamin D levels were maintained during the course of therapy with the same dosage as in the lead-in phase. The control group of 36 patients (mean age 49 ± 7 years, 60% male) received peg-interferon-α-2b (1.5 μg/kg body weight) plus ribavirin (1000-1200 mg/d) without vitamin D3 for 48 wk.

Efficacy assessments

Plasma HCV-RNA levels were measured using the COBAS Taq Man HCV assay, version 1.0 (Roche Molecular Systems), with a lower limit of quantification of 35-45 IU/mL and a lower limit of detection of 10 IU/mL. HCV-RNA levels were measured at the time of screening and during the treatment period at weeks 4, 12 and 48. All subjects had at least one follow-up visit at 24 wk after the completion of treatment. Those who had undetectable HCV-RNA levels had another follow-up visit 24 wk later, at which time HCV-RNA levels were measured again. Treatment efficacy was defined as SVR, i.e., undetectable HCV-RNA at 24 wk post-treatment. Clearance of HCV-RNA by real-time polymerase chain reaction (RT-PCR) was assessed at week 4 (RVR), week 12 (complete EVR), and at week 48 of treatment response (early treatment response, ETR). Patients with ETR who tested HCV-RNA positive during follow-up were classified as relapsers. Breakthrough was defined as an increase in the HCV-RNA level of one log₁₀ unit compared with the lowest value. Therapy was discontinued if quantitative HCV-RNA levels at week 12 dropped by < 2 log compared with baseline values (non-responders), and at week 24 if HCV-RNA was still detectable in those patients in whom HCV-RNA dropped > 2 log at week 12[^3,15].

Safety assessments

Biochemical assessments were performed at each visit during the treatment period and at the post-treatment follow-up visit. Data on adverse events were collected and physical examinations were also performed each time. The safety assessment included complete blood count, antinuclear antibody, and thyroid-stimulating hormone levels. Peg-interferon α 2b was reduced to 1.0 μg/kg body weight in patients with a < 750 neutrophil count and withdrawn temporarily in patients with a < 500 neutrophil count. The same dose reduction was applied if platelet levels fell under 50 000 cells/mm³, with peg-interferon being discontinued when the 25 000 cell/mm³ threshold was reached. In both treatment arms, the ribavirin dose was tapered by 200 mg/d in patients with a hemoglobin level < 10 g/dL, and discontinued altogether in patients with a level < 8.0 g/dL.

Clinical and laboratory measurements

Vitamin D levels: 25 (OH)-vitamin D3 levels were determined by 125 I-radioimmunoassay (Dia-Sorin, Stillwater, MN, United States)[¹⁶]. 25-OH vitamin D is the major circulating form of vitamin D and is used as an indicator of vitamin D status. Vitamin D deficiency was defined as a 25 (OH)-vitamin D serum level < 12 ng/mL, vitamin D insufficiency as 25 (OH)-vitamin D levels of 12-32 ng/mL, and vitamin D sufficiency as levels > 32 ng/mL[¹²]. Insulin resistance was estimated using the homeostasis model assessment (HOMA-IR)[¹⁷]. HOMA-IR was measured at baseline and at 4 wk in both study groups. Body mass index (BMI) was calculated as weight in kilograms divided by the square of height in meters. Obesity was defined as a BMI exceeding 28 kg/m². C-reactive protein was determined by the nephelometric method[¹⁸]. Paraoxonase activity was measured according to a method using phenylacetate as a substrate[¹⁹]. α tocopherol (vitamin E) was estimated spectrophotometrically[²⁰]. Malondialdehyde concentration was estimated spectrophotometrically using the thiobarbituric acid assay[²¹]. Calcium, phosphor, vitamin B12, thyroid-stimulating hormone, glucose, insulin, liver enzymes, albumin, bilirubin, prothrombin time, and creatinine were measured by standard biochemical tests.

Statistical analysis

Results were expressed as mean ± SD. The difference between the two groups was assessed by the chi-squared test for categorical variables and by the Mann-Whitney rank test for continuous variables. The Spearman correlation was used to express correlations between variables. The primary study endpoint was evidence of the influence of vitamin D on the viral response at weeks 4 and 12 during therapy and at week 24 post-treatment. Logistic regression analysis was performed to detect independent predictors for SVR. The significance level was set at P < 0.05. The statistical analyses were carried out with the WINSTAT (Kalmia, CA, United States) software program.

RESULTS

At baseline, 21% of the patients in the treatment group had severe vitamin D deficiency (< 12 ng/mL), 59% had insufficiency, and 20% had sufficient vitamin D levels. The control group baseline tests showed that 27% had vitamin D deficiency, 60% had insufficiency, and 13% had sufficient vitamin D levels. Table 1 shows the clinical and biochemical parameters of the patient populations.

(Click table to enlarge)

The treatment group had higher BMI levels, viral loads, and fibrosis scores > F2 than the controls (27 ± 4 kg/m²vs 24 ± 3 kg/m², P = 0.014; > 800 000 IU/mL, 50% vs 42%, P = 0.033; 42% vs 19%, P = 0.001, respectively). There were no differences between the two groups in terms of age, HCV genotype, baseline HCV-RNA, ethnic background, or aminotransferases levels.

​Figure 1 depicts the baseline and week 4 vitamin D levels at the beginning of antiviral therapy. Serum vitamin D levels were significantly lower at baseline (20.5 ± 9.0 ng/mL) and increased after 4 wk of vitamin D treatment to a mean level of 37 ± 10 ng/mL. Baseline vitamin D levels were also lower in the control group (19 ± 6 ng/mL, ​Table 2).

Figure 1 Vitamin D serum levels before and at 4 wk after the beginning of antiviral treatment + vitamin D supplementation (n = 36). Bars represent standard error

(Click table to enlarge)

Figures 2 and 3 show the rates of RVR, EVR, and SVR in the treatment and control groups. At week 4, 16 (44%) patients in the treatment group and 6 (17%) controls were HCV-RNA negative, and at week 12, 34 (94%) and 17 (48%), respectively, were HCV-RNA negative (P < 0.001 for each week). Twenty-four weeks after the cessation of therapy (SVR), 31 (86%) patients in the treatment group and 15 (42%) controls were HCV-RNA negative (P < 0.001). The percentage of relapses and non-responders and the biomarkers of insulin resistance, inflammation, pro-oxidant levels, antioxidant levels, and baseline vitamin D, vitamin E, and vitamin B12 serum levels are shown in ​Table 2 for both groups.

Figure 2 Rate (%) of the rapid viral response and rate of early viral response in the treatment (n = 36) and control (n = 36) groups. RVR was defined as undetectable HCV RNA at 4 wk during treatment. Complete EVR (cEVR) was defined as undetectable HCV RNA at 12 wk during treatment. SOC: Standard of care; RVR: Rapid viral response; EVR: Early viral response; HCV: Hepatitis C virus; SVR: Sustained viral response.

Figure 3 Rate of sustained viral response in the treatment group (Vitamin D + SOC, n = 31/36) and the control group (n = 15/36, SOC) 6 mo after cessation of treatment. SVR was defined as undetectable HCV-RNA at 24 wk post-treatment. Bars represent standard error. SOC: Standard of care; SVR: Sustained viral response; HCV: Hepatitis C virus.

The rate of viral breakthrough was null. The rates of relapse and non-response were significantly lower in the treatment group compared with the control group [n = 3 (8%) vs n = 13 (36%), P < 0.001, and 2 (6%) vs 8 (22%), P < 0.01, respectively]. The HOMA-IR index decreased significantly after 4 wk of treatment with vitamin D compared with the control group (from 4.5 ± 1.4 to 2.3 ± 1.0, P < 0.01 vs 4.6 ± 5.7 to 5.0 ± 4.0, respectively, P < 0.1). There was no difference between groups for malondialdehyde, paraoxonase, vitamin E, vitamin B12, C-reactive protein, and triglyceride levels.

The adherence to vitamin D treatment was excellent during the entire course, and all patients in the treatment group achieved the target level. Vitamin D levels were maintained during the course of therapy with the same dosage (2000 IU/d) as in the lead-in phase. Predictive factors for SVR in patients treated with Peg/RBV combination therapy are shown in Table 3.

(Click table to enlarge)

Viral load, advanced fibrosis, baseline vitamin D levels, changes in HOMA-IR, and vitamin D supplementation were significant univariate predictors of SVR. Viral load, vitamin D supplementation, advanced fibrosis and changes in HOMA-IR remained as independent predictors in the multivariate analysis. Thus, vitamin D supplementation emerged as being more responsible for higher SVR than the baseline vitamin D level.

The most common adverse events were mild in nature, similar in both groups, and consistent with typical Peg/RBV-induced systemic symptoms. They included nausea (n = 4), headache (n = 4), insomnia (n = 5), chills (n = 4), myalgia (n = 3), pyrexia (n = 3), pruritus (n = 2), mild neutropenia (n = 3), mild thrombocytopenia (n = 5), and mild anemia (n = 3). There were no serious adverse events. Adherence to Peg/RBV combination therapy was excellent, and there was no difference in dose reduction Peg/RBV combination therapy due to adverse events in either group. No patient discontinued treatment. Changes in laboratory values during the study were consistent with those reported in association with the combined use of Peg/RBV[³].

DISCUSSION

The results of this study suggest that the addition of a vitamin D supplement to current standard therapy can significantly improve the rate of RVR, EVR and SVR in treatment-naïve patients with HCV genotype 1 compared the rates with standard therapy alone. The observed SVR in the control group (42%) was consistent with previous reports[^2,3]. Overall there was a marked increase in the virologic response at week 4 (44% vs 17%), week 12 (94% vs 48%), and week 24 after the cessation of therapy (86% vs 42%), and a low rate of relapse (8% vs 36%) with vitamin D supplementation compared with no supplementation. The rate of relapse in the control group was within the reported 18%-40% range for current standard HCV antiviral therapy[^2,22].

There are only two reports examining the association between vitamin D status and outcome of antiviral therapy in patients with chronic HCV viral infection. Petta and co-workers retrospectively analyzed a cohort of 167 patients treated with Peg/RBV for hepatitis C, and detected an association between lower vitamin D serum levels and failure to achieve SVR[²³]. Our results provide further support for that data. The second study by Bitetto and co-workers showed that vitamin D supplementation improved the response to antiviral treatment for recurrent HCV in liver transplant recipients[²⁴]. Several differences between those two studies should be noted. Bitetto and co-workers’ HCV patients were immunocompromised, and they were supplemented with low-dose vitamin D (800 IU/d) after liver transplantation. In addition, most of their HCV patients (75%) had low vitamin D levels despite treatment. Finally, that study was retrospective and focused on the prevention of osteoporosis, not on the treatment of hepatitis C.

The exact mechanism of action leading to improved RVR, EVR, and SVR in patients receiving vitamin D is unknown. Vitamin D is metabolized by the liver and converted to 1,25-dihydroxy-vitamin D3, which is the active form of the vitamin[^6,7]. Individuals with chronic liver disease may have poor conversion from vitamin D3 or any of its other biologically active metabolites[¹¹]. 1,25 vitamin D3 appears to modulate immunity principally via regulation of T-cell function[²⁵]. The vitamin D receptor (VDR) is expressed on virtually every type of cell involved in immunity[²⁶]. The immunomodulatory actions of vitamin D are elicited through its direct action on T-cell antigen-presenting cell function[²⁷]. T helper cell type 1 (TH1) actions are intensified when vitamin D is insufficient, as in the majority of our patient population, or when signals through VDR are weak. Regulatory T cell and TH2 cells are diminished, thus favoring an autoimmune TH1 response[²⁸]. This is a pro-inflammatory response which may impair IFN and insulin signaling, thus decreasing the viral response[^29,30]. A recent study on 120 patients with chronic HCV genotype 1 infections reported that a TH1 to TH2 ratio of < 15.5 was significantly associated with SVR (odds ratio 9.6)[³¹]. TH1 and TH2 measurements were not performed in the present study. Persistent HCV infection modulates the balance between immune stimulatory and inhibitory cytokines which can prolong inflammation and lead to fibrosis and chronic liver diseases[³²]. More recently, Gutierrez and co-workers showed that vitamin D3 increased VDR protein expression and inhibited viral replication in cell culture[³³].

It is well known that people of African and Hispanic descent are less likely to respond to standard therapy[³⁴]. This may be due to a polymorphism of the interleukin (IL)-28B gene, polymorphism of VDR or vitamin D deficiency[^13,35]. The vast majority of the Russian/Jewish/Arab patients in the present study had vitamin D insufficiency, possibly related to paradoxically low exposure to the sun in this predominantly sunny country and/or to a low supply of vitamin D from their diet.

The impact of diet on liver fibrosis and on response to IFN therapy in patients with HCV chronic hepatitis has been reported before[³⁶]. HCV patients also lack vitamins E and B12[^37,38]. A recent study showed that higher levels of vitamin B12 were associated with SVR, but there was no difference in serum levels of those vitamins between the group treated with vitamin D and the controls[³⁹].

Insulin resistance emerged as one of the most important host factors in the prediction of the response in non-diabetic HCV patients treated with Peg/RBV, and is a common factor in the features associated with difficult-to-treat patients[⁴⁰]. Vitamin D is also known to help prevent type 2 diabetes, and it is possible that low levels of vitamin D lead to insulin resistance[⁹]. The direct effect of vitamin D may be mediated by binding of its circulating active form to the pancreatic B cell vitamin D receptor[⁴¹]. Vitamin D deficiency or insufficiency may alter the balance between the extracellular and intracellular cell calcium pools, which may interfere with normal insulin release[⁴²]. Thus, a lack of either calcium or vitamin D can result in peripheral insulin resistance[⁴¹]. Moreover, oxidative stress leeches calcium, and vitamin D helps absorb calcium[⁴³]. Our current results confirm these findings: the HOMA-IR was higher at baseline in the vitamin D treatment group and improved after 4 wk of therapy compared to the control group. Moreover, the changes in HOMA-IR were strongly associated with SVR (multivariate analysis).

The definition of normal vitamin D serum levels is a subject of debate. In the current study, increasing the vitamin level D to > 32 ng/mL increased the response to antiviral therapy to the same extent in patients with vitamin D deficiency as well as those with vitamin D insufficiency. Multivariate analysis revealed that viral load, advanced fibrosis and vitamin D supplementation remained as independent predictors. Thus, it can be concluded that vitamin D supplementation is responsible for a higher SVR, rather than the baseline vitamin D level. It remains to be determined whether the addition of vitamin D acts by a mechanism other than improvement of insulin resistance or immune function such as the upregulation of toll-like receptors involved in the immune response in HCV-infected patients

Limitations of the present study include the small number of patients, lack of vitamin D level assessment during therapy for the treatment and control groups, and that this prospective and randomized study was not placebo-controlled, thus the patients knew whether or not they received a vitamin D supplement. Another limitation is the lack of data on the TH1 and TH2 immune response. The identification of determinants of the response, such as polymorphisms of the IL28B gene, polymorphism of the VDR and immune function[^13,35], may help explain the difference in response rates between patients with different ethnic backgrounds. This was not done in our study since data on IL-28B and on VDR polymorphism were not available at the time the study was designed.

In conclusion, the addition of vitamin D to Peg/RBV combination therapy in treatment-naïve patients who were infected with HCV genotype 1 significantly increased the rates of rapid, early, and sustained viral responses.

COMMENTS

Background

Treating chronic hepatitis C virus (HCV) (genotype1) patients with pegylated interferon and ribavirin, which is considered to be the standard of care, has achieved viral clearance in less than 50% of the patients. Vitamin D is a potent immunomodulator with a beneficial effect against viral and bacterial infections. The vast majority of patients with chronic hepatitis C have low levels of vitamin D. Different new drugs such as protease or polymerase inhibitors are still under investigation and are expensive and have many side effects like rash.

Research frontiers

Vitamin D deficiency is well documented in patients with chronic liver disease. However, treating patients with chronic HCV infection by adding a vitamin D supplement to the standard of care has not been addressed. There are only two reports dealing with the association between vitamin D status and outcome of antiviral therapy for chronic HCV infection.

Innovations and breakthroughs

The current study shows that adding a vitamin D supplement to pegylated interferon and ribavirin significantly increases the rapid, early and late clearance of the virus, in chronic hepatitis C genotype 1 treatment-naïve patients.

Applications

This study emphasizes the importance of vitamin D supplementation when added to standard treatment in all patients with chronic hepatitis C. Further studies are needed to explain the mechanism of vitamin D supplementation for these patients.

Terminology

Hepatitis C is a chronic liver infection that can be complicated by liver failure and liver cancer. Clearance of the virus from the blood is achievable by a combination of pegylated interferon and ribavirin in less than 50% of the patients. Vitamin D has an important role in the treatment of different bacterial and viral infections; this vitamin is synthesized in the skin by absorption of ultraviolet from the sun light. The mechanism of action of this vitamin is unknown, but it may improve the activities of immune cells that are important in the eradication of HCV.

Peer review

This is a well conducted study with a relevant finding, and it is well written.

Footnotes

Peer reviewer: Sabine Mihm, Professor, Department of Gastroenterology, Georg-August-University, Robert-Koch-Str 40, Göttingen D-37099, Germany

S- Editor Tian L L- Editor Cant MR E- Editor Zhang DN

References

Source

Evolving URMC Studies Uphold Precision Radiation to Control Cancer

January 11, 2012

The University of Rochester Medical Center has been a leader in the study of stereotactic body radiation therapy (SBRT) for the past decade, and two of the latest research projects show that SBRT is emerging as an important tool for more people with advanced cancer.

Alan W. Katz, M.D., M.P.H., and Michael T. Milano, M.D., Ph.D., in separate studies in the International Journal of Radiation Oncology, Biology, Physics, report that SBRT can lead to long-term survival for liver cancer patients who are awaiting a transplant, and for select patients with early metastasis of many types of cancer.

Their work is the latest from a body of research conducted at the URMC’s James P. Wilmot Cancer Center, which was among the first institutions in the country to use SBRT. The therapy delivers high doses of radiation precisely to the tumor without harming adjacent tissues. Doctors use a coordinate system to map their target, and then deliver multiple, intersecting radiation beams at the spot, like several flashlights focused in one area. Because of their early use of this technology, Wilmot scientists have been able to study patients for longer periods under a variety of circumstances.

“Although we have known for quite some time that it is possible to treat metastatic disease, the technology needed to catch up to the concept,” said Milano, an associate professor of Radiation Oncology at Wilmot. “Now, physicians have a greater comfort level with SBRT due to treatment and imaging technology that can pinpoint smaller tumors, and data from our institution and others showing that SBRT works very well in certain cases.”

Katz, who is also an associate professor of Radiation Oncology, agreed. “Compared to older, more invasive treatments, stereotactic body radiation is usually very well tolerated, particularly as a bridge treatment,” he said. “And many people who develop liver cancer also have serious underlying conditions such hepatitis and cirrhosis of the liver, so often they are not candidates for chemotherapy and they are looking for novel, less-invasive ways to delay progression of their disease.”

In fact, SBRT is particularly useful for liver cancer. Patients seeking a liver transplant must meet the transplant criteria after a typical year-long waiting period. Bridge therapies are required during this time to keep the disease from spreading, and to improve chances for long-term survival.

Katz’s study was small, involving 18 patients initially and then only 12 who qualified for a transplant a few months after receiving SBRT between 2007 and 2009. However, the survival outcomes were significant: approximately 19 months after surgery all patients were doing well with no recurrences and no significant toxicities from the treatment, Katz said. (Average five-year survival rates for liver cancer vary greatly, ranging from 10 percent to 60 percent, depending upon the stage at diagnosis and other factors.)

Milano studied the long-term outcomes of 121 people who were treated with SBRT after being diagnosed with recurrences from a variety of cancers, including breast, prostate, lung and colon. Only people with five or fewer metastatic lesions were eligible. Breast cancer patients fared the best, perhaps because that cancer tends to be more indolent, he said.

For example, half of the 39 breast cancer patients with metastasis survived for more than four years after SBRT, and one-third of them were alive at seven-year follow-up visits. The study also noted that for the breast cancer patients who had bone metastasis, after SBRT none of their lesions recurred.

With other types of cancer, SBRT was less successful in terms of long-term survival but still was useful at controlling new lesions and thus delaying further spread of the disease in 74 percent of the patients. The two-year overall survival rate for 82 patients with metastasis from colon, lung, esophagus, or sarcomas, was 39 percent. Seven of 82 patients were alive after seven years.

When cancer spreads from the original site in the body to another site, the chances of a cure are slim. The primary goal is to slow the disease and relieve symptoms. Future research is aimed at investigating the newer, targeted treatments that might offer the best chance at prolonging life while maintaining quality of life.

Milano said further study of SBRT should address which subgroups of patients, aside from people with breast cancer, are likely to derive the most benefit from SBRT, and at what doses. When the URMC first began studying SBRT in 2001, 5-Gy fractions of radiation delivered to the organs was considered novel. Since then, however, researchers and clinicians have shown that doses of 10 to 20 Gy can be safe and effective, and the higher doses could potentially result in even better long-term survival.

For Media Inquiries:
Leslie Orr
(585) 275-5774
Email Leslie Orr

Source

NIH study to test treatment for fatty liver disease in children

For Immediate Release
Wednesday, January 11, 2012

Contact:
Leslie Curtis
Amy F. Reiter
301-496-3583

With the launch of a new clinical trial supported by the National Institutes of Health, researchers are working to determine whether treating children diagnosed with the most severe form of fatty liver disease with a drug called cysteamine will help improve the liver.

The trial, called Cysteamine Bitartrate Delayed-Release for the Treatment of Nonalcoholic Fatty Liver Disease in Children (CyNCh),will enroll 160 boys and girls ages 8 to 17 with nonalcoholic fatty liver disease (NAFLD). The participants will receive cysteamine or placebo by mouth twice a day for a year. There are no weight cutoffs or percentiles for the children participating in CyNCh. However, more than 90 percent of the children are expected to be overweight or obese. Participants need a baseline biopsy that confirms severe NAFLD to be eligible for the study. Children with poorly managed diabetes, heart disease, and other chronic liver diseases will be excluded.

NAFLD covers a range of severity from simple liver disease without injury, called steatosis, to the more concerning nonalcoholic steatohepatitis, or NASH, which includes fat accumulation, inflammation, and liver injury. Most children with fatty liver disease are overweight and resistant to insulin, a hormone that regulates energy. The only way to distinguish NASH from other forms of fatty liver disease is with a liver biopsy.

"We did not see fatty liver disease in children until recently," said Edward Doo, M.D., NASH Clinical Research Network project scientist and director of the Liver Diseases Program at NIH's National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), which is funding the study in collaboration with Raptor Pharmaceutical of Novato, Calif., which makes the drug and will provide it to the trial. "Fatty liver disease affects about 17 percent of children in the United States. This rise in the number of children with NAFLD most likely mirrors the increase in obesity, which affects more than 16 percent of American children and teens," Dr. Doo said.

Results from a small pilot study using cysteamine in 11 children with NASH suggest that it improves liver enzymes by reducing toxins that can damage the liver. Cysteamine is approved to treat cystinosis, a genetic disease that causes the amino acid cystine to accumulate in the kidneys, liver, eyes, brain, and white blood cells. Modest weight loss through diet and physical activity may help some children with fatty liver disease, but it is a treatment option that seldom helps people meet their goals. "We know that following a weight loss plan for many children and adults can be daunting, especially if they have limited access to healthy food options that are low in fat, added sugars, and calories, and infrequent opportunities for physical activity," said Joel E. Lavine, M.D., Ph.D., a CyNCh principal investigator and professor of pediatrics at Columbia University, New York City. "Hopefully, this trial will move us closer to finding a safe and effective treatment that helps children with fatty liver disease."

NAFLD can be a precursor to NASH, which may progress to cirrhosis, liver failure and liver cancer. NAFLD may also increase a patient’s risk of developing heart disease. A healthy liver helps the body remove harmful chemicals from the blood, fight infection and digest food. If too much scar tissue forms, the liver could fail. Then a liver transplant is required. "We are concerned that the disease may advance as children become adults and increase their risk for cirrhosis, liver failure, liver transplantation, and death as adults," said Stephen P. James, M.D., director of the NIDDK’s Digestive Diseases and Nutrition Division. "This multicenter, double-blind trial offers researchers and NIDDK an opportunity to rigorously assess how safe and effective cysteamine is in treating children with NASH, as well as to reveal new avenues worthy of scientific study."

The following clinical centers are conducting the CyNCh trial:

• Children's Memorial Hospital, Chicago
• Cincinnati Children’s Hospital Medical Center
• Columbia University, New York City
• Indiana University, Indianapolis
• Mount Sinai Medical Center, New York City
• St. Louis University
• Texas Children's Hospital, Houston
• University of California, San Diego
• University of California, San Francisco
• University of Washington, Seattle

For more information:

• NIDDK's NASH Clinical Research Network: https://jhuccs1.us/nash/open/centers/centers.htm
• NIDDK's Action Plan for Liver Disease Research: www.liverplan.niddk.nih.gov
• National Digestive Diseases Information Clearinghouse: http://digestive.niddk.nih.gov
• Weight-control Information Network: www.win.niddk.nih.gov
• ClinicalTrials.gov: www.clinicaltrials.gov

The NIDDK, a component of the NIH, conducts and supports research on diabetes and other endocrine and metabolic diseases; digestive diseases, nutrition and obesity; and kidney, urologic and hematologic diseases. Spanning the full spectrum of medicine and afflicting people of all ages and ethnic groups, these diseases encompass some of the most common, severe and disabling conditions affecting Americans. For more information about the NIDDK and its programs, see www.niddk.nih.gov. Education programs for diabetes and kidney disease offer information and resources for patients and health professionals.

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

Source

Minimal Transmission of HIV Despite Persistently High Transmission of Hepatitis C Virus in a Swedish Needle Exchange Program

From Journal of Viral Hepatitis

M. Alanko Blomé; P. Björkman; L. Flamholc; H. Jacobsson; V. Molnegren; A. Widell

Posted: 01/10/2012; J Viral Hepat. 2011;18(12):831-839. © 2011 Blackwell Publishing

Abstract and Introduction

Abstract

The aim of this study was to examine the prevalence and incidence of HIV and hepatitis B and C (HBV and HCV) among injecting drug users in a Swedish needle exchange programme (NEP) and to identify risk factors for blood-borne transmission. A series of serum samples from NEP participants enrolled from 1997 to 2005 were tested for markers of HIV, HBV and HCV (including retrospective testing for HCV RNA in the last anti-HCV-negative sample from each anti-HCV seroconverter). Prevalence and incidence were correlated with self-reported baseline characteristics. Among 831 participants available for follow-up, one was HIV positive at baseline and two seroconverted to anti-HIV during the follow-up of 2433 HIV-negative person-years [incidence 0.08 per 100 person-years at risk (pyr); compared to 0.0 in a previous assessment of the same NEP covering 1990–1993]. The corresponding values for HBV were 3.4/100 pyr (1990–1993: 11.7) and for HCV 38.3/100 pyr (1990–1993: 27.3). HCV seroconversions occurred mostly during the first year after NEP enrolment. Of the 332 cases testing anti-HCV negative at enrolment, 37 were positive for HCV RNA in the same baseline sample (adjusted HCV incidence 31.5/100 pyr). HCV seroconversion during follow-up was significantly associated with mixed injection use of amphetamine and heroin, and a history of incarceration at baseline. In this NEP setting, HIV prevalence and incidence remained low and HBV incidence declined because of vaccination, but transmission of HCV was persistently high. HCV RNA testing in anti-HCV-negative NEP participants led to more accurate identification of timepoints for transmission.

Introduction

Injecting drug use is an important route of HIV transmission worldwide,^[1,2] and hence targeting injecting drug users (IDUs) is a priority in HIV prevention. IDUs are also at risk of infection with other blood-borne pathogens, especially hepatitis B virus (HBV) and hepatitis C virus (HCV). Because these viruses share transmission routes, measures taken to prevent HIV might also be expected to reduce the spread of HBV and HCV. A wide range of strategies have been attempted to decrease blood-borne transmission among IDUs, as exemplified by harm reduction interventions such as methadone maintenance therapy (MMT) and needle exchange programmes (NEPs). Although NEPs are recommended by the World Health Organization (WHO), there is no unequivocal evidence from controlled studies demonstrating the protective efficacy of such schemes.^[3,4] Most evaluations of the effectiveness of NEPs regarding HIV compare populations or assess injection-related risk behaviour,^[5–7] and most studies of virological markers have been cross-sectional.^[8,9] HIV incidence studies among NEP participants have in general revealed low rates of seroconversion, especially when NEPs had been initiated before significant spread of HIV occurred in the target population.^[10–13] Such results agree with our earlier observations regarding NEP participants in Malmö, Sweden, in 1990–1993.^[14] However, a major concern in our Malmö NEP was ongoing transmission of HBV and HCV, which indicated blood-borne transmission despite access to clean injection equipment. We subsequently added HBV immunization to the program, as well as targeted health education concerning the risks of HCV transmission for both HCV-infected and HCV-uninfected participants.

The objective of the present study was to further investigate the recent epidemiology of HIV, HBV and HCV among new participants in the Malmö NEP, which is one of only two such programs in Sweden, and also to determine whether incident HCV infection was linked to baseline drug use–related risk factors.

Methods

Setting

In Sweden (pop. 9 million), approximately 4500 people had been diagnosed with HIV by the year 2005 (prevalence 0.04%), and, from 1995 to 2005, about 300 new cases were reported annually, with approximately 10% infected through injection drug use.^[15] The prevalence of previous HBV exposure in the general middle-aged population in urban areas was approximately 4% in 2000.^[16] Considering HCV, the prevalence in 1996–2006 was 0.5%, and injection drug use was reported to be the transmission route in 65% of the registered cases.^[17] No data are available regarding the incidence of HCV in Sweden.

The city of Malmö (pop. about 270 000) is located in Skåne County in the southernmost part of Sweden (pop. about 1 million), approximately 20 km from Copenhagen, Denmark. From 1997 to 2005, the average annual incidence of HIV in Skåne County was 39 (range 31–51), and most infections were acquired through sexual transmission. In 2005, approximately 500 people diagnosed with HIV were living in Skåne County.^[18] According to estimations,^[19] there were 1600 IDUs in Malmö in 1998 (1080 per 100 000 inhabitants aged 15–54 years). In 2006, there were 1000 HIV-infected IDUs in the entire country, and 6% of those IDUs lived in Malmö while the majority (72%) lived in the capital city of Stockholm.

The Malmö Needle Exchange Programme

The Malmö NEP was initiated in 1987, and it is located in the University Hospital compound at the Department of Infectious Diseases. The staff consists of two assistant nurses, a registered nurse, a social worker, a midwife and a physician. The NEP is open daytime during weekdays. A total of 3950 new participants enrolled in the Malmö NEP, and approximately 1150 persons were active in the programme each year during that period. Prerequisites for enrolment are self-reported injection drug use, age ≥20 years, signs of recent venipuncture and consent to HIV testing (which may be performed under code). About 140–200 new participants enrol annually. At the time of registration, structured data are collected and risk reduction counselling is given. A maximum of 20 needles and 10 syringes can be obtained per visit. Most participants who have initially chosen to be anonymous later decide to allow use of their unique national identity number (NIN) for management of data and test results, after which collected data are updated. NINs are used in all Swedish hospital and laboratory databases and in population registers.

Those susceptible to either HIV, HBV and/or HCV infection are serologically tested approximately every 3 months until seroconversion occurs. In addition, immunization against hepatitis B and A has been offered since 1994 and 1999, respectively. Educational videos aimed at both reducing infection and preventing overdose are shown in the waiting room, and participants are given barrier contraceptives, pregnancy screening and treatment for sexually transmitted infections. Basic medical care, psychosocial support and referral to detoxification or methadone/buprenorphine maintenance clinics are also offered, all free of charge.

Subjects

A total of 1661 participants registered in the Malmö NEP between 1 January 1997 and 31 December 2005 were eligible for inclusion in the present study, and a NIN was available for 1183 of those individuals. The remaining 478 subjects were mainly sporadic visitors who refused both use of their NINs and blood sampling (n = 454), or agreed only to blood sampling (n = 24), and thus identification of serological markers was not possible. Among the 1183 persons who allowed use of their NINs, 831 provided two or more samples and underwent two or more registered needle/syringe exchanges, and they were included in the analysis of incidence and risk factors prevalent at enrolment; this group is referred to as the longitudinal cohort. The 352 persons providing only one blood sample were analysed regarding prevalence of viral markers, demographics and risk profile; this group is called the baseline-only cohort.

Virological Testing

Serological Tests Virological results were retrieved from the mainframe computer at the hospital microbiology laboratory. During the study period, testing was progressively upgraded with new instruments and techniques [1997, chemiluminescence assay using avidin-coated tubes (Boehringer, Mannheim, Germany); 1998, bead-based ELISA (CobasCore; Roche, Mannheim, Germany); 2001, microparticle-based EIA (Abbott AxSym, Abbott Park, IL, USA)]. The markers studied were as follows: for HIV, anti-HIV antibodies followed by immunoblotting if needed; for HBV, hepatitis B surface antigen (HBsAg), core antibodies (anti-HBc) and surface antibodies (anti-HBs); for HCV, anti-HCV antibodies followed by immunoblotting if needed. All assays were continuously evaluated in international proficiency panels. Sera were routinely stored at −20 °C, which allowed retrospective retesting of relevant sera with the most sensitive anti-HCV assay (third generation Abbott AxSym).

Molecular Tests To define the time of HCV acquisition more exactly, all the latest available preseroconversion sera testing anti-HCV negative in the third-generation AxSym assay were retrospectively tested for HCV RNA in a Taqman48 Roche assay (Roche Diagnostics). Because the sample volumes were limited and the Taqman system requires 1 mL of starting material, participant sera were prediluted 1:10 in negative serum, which resulted in a detection limit of 150 IU/mL for HCV RNA.

Statistical Methods

Odds ratios, Mann–Whitney U-tests and Fisher's Exact tests were calculated to analyse differences between groups. Univariate and multiple logistic regression analyses were carried out to identify baseline risk factors associated for previous HCV exposure and with HCV seroconversion. Kaplan–Meier curves with log rank tests were plotted to visualize and test time to seroconversion between different year periods. The statistical tests were performed in spss 15.0 for Windows ( SPSS Inc., Chicago, IL, USA). P-values <0.05 were considered statistically significant. Odds Ratios (ORs) were considered as significant if the entire 95% confidence range either was above or below 1.0

The timepoint of seroconversion to HIV, HBV and HCV was defined as the midpoint between the last antibody-negative and the first antibody-positive sample. The timepoint of HCV infection was adjusted by the results of HCV RNA testing. The monitored follow-up period spanned from the first serum sample collected after registration in the NEP to the last sample taken before the end of 2005.

Ethical Considerations

After approval by the regional research ethics committee, the purpose and the procedure of our study were announced on posters in the NEP and in advertisements in the local press, including a widely distributed free daily newspaper. An opt-out strategy was used, assuming consent for NEP participants who did not actively object to study inclusion. All analyses were coded, with the exception of linking of the longitudinal laboratory results.

Results

Baseline Characteristics of Injecting Drug Users Who Did or Did Not Provide a National Identity Number

Participants with and without available NINs did not differ significantly with regard to gender, age or geographic origin (data not shown). However, only 50% of those with a NIN had spent time in prison prior to the enrolment in the NEP compared to 57% of those not providing a NIN (OR 0.76, CI 0.61–0.94: P = 0.013). Among those who did provide a NIN, injection of amphetamine only was less prevalent (OR 0.78, CI 0.62–0.98; P = 0.039), whereas cannabis use was significantly more common (OR 1.86, CI 1.41–2.45; P < 0.001).

Baseline Prevalence of HIV, HBV and HCV Markers in Injecting Drug Users Who Provided a National Identity Number

Longitudinal Cohort vs Baseline-only Cohort The baseline prevalence of serological markers for all identified patients was 0.34% (4/1183) for anti-HIV, 32% (380/1183) for anti-HBc and 64% (758/1183) for anti-HCV.

Markers of previous exposure to HBV and HCV were significantly more prevalent in the baseline-only cohort compared to the longitudinal cohort for HBV (OR 1.82, CI 1.40–2.37; P < 0.001) and for HCV (OR 1.85, CI 1.41–2.44; P < 0.001). The baseline-only cohort also had a significantly longer history of injecting both heroin and amphetamine before enrolling in the NEP (P < 0.001). Likewise, the use of cannabis (OR 2.01, CI 1.23–3.28; P = 0.004) and oral amphetamine (OR 2.70, CI 2.08–3.50; P < 0.001) was more prevalent in the baseline-only cohort. This group also reported having spent time in police custody more often (OR 1.69, CI 1.21–2.38; P = 0.002) or in prison (OR 1.50, CI 1.16–1.92; P = 0.002), or had been in care under the social services law (OR 1.73, CI 1.27–2.35; P = 0.001).

Longitudinal Cohort HIV. One of the 831 persons in the longitudinal cohort was anti-HIV positive at enrolment but had tested anti-HIV negative 3 months previously.

HBV. Markers of HBV exposure were detected at baseline in 236 persons (28%), 10 of whom developed chronic HBs antigenemia. Neither male gender (OR 1.30, CI 0.91–1.86) nor being born outside Sweden (OR 0.79, CI 0.54–1.14) was associated with a higher risk of HBV exposure. Exclusive use of heroin was associated with a significantly lower risk of HBV exposure compared to exclusive use of amphetamine or mixed use of those drugs (OR 0.48, 0.31–0.74; P = 0.0008). Furthermore, testing positive for HBV markers was strongly correlated with the presence of anti-HCV (OR 5.91, CI 3.97–8.80). Only seven persons had received full HBV vaccination and achieved protective levels of anti-HBs before NEP enrolment.

HCV. At baseline, anti-HCV was found in 499 (60%) participants. Univariate comparison of participants dichotomized for baseline anti-HCV status showed that presence of anti-HCV was associated with (Table 1, left section) older age (OR 1.09, CI 1.07–1.11; P < 0.001), longer duration of heroin injection (OR 1.11, CI 1.07–1.15; P < 0.001), longer duration of amphetamine injection (OR 1.11, CI 1.09–1.14; P < 0.001), parenteral use of both heroin and amphetamine (OR 1.65 CI 1.24–2.19; P = 0.001), use of oral amphetamine (OR 1.52, CI 1.13–2.04; P = 0.006), previous incarceration (OR 2.43, CI 1.82–3.25; P < 0.001), time in residential treatment centres (OR 1.39, CI 1.05–1.84; P = 0.021) and exposure to HBV (OR 5.72, CI 3.86–8.48; P < 0.001). Male gender (OR 0.68, CI 0.49–0.95; P = 0.023), intravenous heroin (OR 0.34, CI 0.24–0.48; P < 0.001) and oral heroin (OR 0.52, CI 0.33–0.82; P = 0.006) use were associated with a lower risk of anti-HCVseropositivity. By multivariate analysis, the following factors were significant: male gender (OR 0.39, CI 0.26–0.58; P < 0.001), higher age at entry (OR 1.03, CI 1.01–1.06; P = 0.007), longer duration of parenteral heroin (OR 1.06, CI 1.01–1.11; P = 0.011) and amphetamine (OR 1.06 CI 1.03–1.09; P < 0.001) use, previous incarceration (OR 1.59, CI 1.10–2.29; P = 0.013), residential treatment (OR 1.59, CI 1.01–2.51; P = 0.045) and markers of HBV exposure (OR 2.75, CI 1.76–4.32; P < 0.001).

Incidence of HIV, HBV and HCV Markers in the Longitudinal Cohort

HIV In 1999, seroconversion to anti-HIV occurred in two men (24 and 27 years of age, both anti-HCV positive). Anti-HIV were detected in one of those men 10 months after the first anti-HIV-negative registration sample; he had not visited the NEP for eight consecutive months during that period. The other man had tested anti-HIV negative 3 months prior to the first anti-HIV positive sample. Thus, the incidence of HIV was 0.082/100 pyr during a total time at risk of 2433 years (Table 2).

Hepatitis B Participants negative for HBsAg and/or anti-HBc were offered vaccination according to a standard three-dose schedule and using a postvaccination titre of anti-HBs >10 IU/mL as a criterion for protection. In the longitudinal cohort, 588 persons were susceptible to HBV. Three hundred and fifty-one of those individuals (60%) received at least three doses of vaccine, and protective levels of anti-HBs were achieved in 321 (91%).

HBV seroconversion occurred in 39 participants (21 with documented HBsAg and anti-HBc, 18 with anti-HBc only). The median interval between NEP enrolment and anti-HBc seroconversion was 17 months (range 2.0–101.0). The follow-up time was 1160 pyr, yielding a seroconversion rate of 3.36/100 pyr (Table 2). Nineteen (48%) of the incident HBV cases had begun vaccination with 11 having received only one dose and 2 two doses. Six subjects with HBV seroconversion had been fully vaccinated but had not achieved anti-HBs ≥10 IU/mL. No incident case of HBV occurred in vaccine responders. Five of the incident HBV cases developed chronic HBV infection. Thirteen (33%) of the 39 HBV seroconverters were susceptible to HCV, and 9 (69%) of those also seroconverted to anti-HCV. Drug use profiles did not differ significantly between those who were and those who were not infected with HBV during participation in the NEP.

Hepatitis C Seroconversion to anti-HCV. During 486 person-years at risk, 186 anti-HCV seroconversions occurred among 332 anti-HCV-negative individuals, resulting in an incidence of 38.3/100 pyr (Table 2). The majority of incident HCV infections occurred during the first 2 years after registration (Fig. 1a).

Figure 1. Time (years) elapsed before seroconversion to anti-HCV after enrolment in the Malmö needle exchange programme. The results are shown without (a) and with (b) adjustment for HCV viraemia in last anti-HCV-negative blood sample.

To assess potential trends over calendar time, we divided the entire cohort into three groups composed of all susceptible subjects registered in the NEP during three successive 3-year study periods. The time to event for those susceptible to HCV was calculated in Kaplan–Meier mode. Because the time of observation was shorter for the last group, events occurring later than the first 12 months after registration were censored. The corresponding time curves to HCV seroconversion are shown in Fig. 2. No significant differences were detected between these three groups.

Figure 2. Anti-HCV-free interval during the first 12 months of participation in the Malmö needle exchange programme among injecting drug users enrolled during three successive periods: 1997–1999, 2000–2002 and 2003–2005.

Risk Factors for anti-HCV Seroconversion. Univariate comparison of those who seroconverted to anti-HCV and those who remained anti-HCV negative showed that seroconversion was associated with the following (Table 1, right section): use of cannabis (OR 2.18, CI 1.02–4.65; P = 0.044), injection of both heroin and amphetamine (OR 1.60, CI 1.01–2.53; P = 0.044), and incarceration prior to enrolment (OR 1.79, CI 1.12–2.86; P = 0.015). Use of intravenous amphetamine (OR 0.55, CI 0.34–0.87; P = 0.012) only and oral amphetamine (OR 0.60, CI 0.38–0.96; P = 0.035) only was associated with a lower risk of seroconversion. Multivariate logistic regression analysis indicated that the duration of intravenous use of amphetamine before enrolment (OR 0.96 CI 0.92–1.00; P = 0.034), reported injection of both amphetamine and heroin (OR 1.87, CI 1.15–3.02; P = 0.011), and incarceration prior to enrolment (OR 1.89, CI 1.14–3.12; P = 0.013) were significant risk factors for HCV seroconversion after joining the programme.

Needle exchange programme participation was significantly longer and the number of visits significantly greater for the anti-HCV seroconverters than for those who remained anti-HCV negative. However, participants with detectable anti-HCV at baseline had a significantly lower median number of NEP visits, as well as a lower frequency of attendance than those who were anti-HCV negative at inclusion (Table 3).

HCV Incidence Adjusted for Serological Window Phase. Because anti-HCV antibodies appear months after infection, the high HCV incidence observed during the first months after enrolment might be explained by HCV infection acquired prior to registration. Among 186 persons who showed anti-HCV seroconversion following enrolment, HCV RNA was detected in the last available anti-HCV-negative sample in 67 cases (Fig. 1b). Thirty-seven of these were HCV viremic in their anti-HCV-negative enrolment sample, leading to a reclassification from incident to prevalent infection in those subjects, with an adjusted incidence of 31.5 per 100 pyr. Comparison of seroconverters who were in serological window phase at enrolment with subjects who acquired HCV after enrolment revealed no significant differences in relation to age or type or duration of drug use (data not shown).

Discussion

For more than two decades, the WHO has promoted needle exchange to prevent sharing of injection equipment and HIV transmission among IDUs. Despite this, many countries have pursued a restrictive policy and in Sweden only two NEPs exist. Furthermore, syringes and needles cannot be purchased legally without a prescription in Sweden.

Because the true efficacy of NEP cannot be demonstrated in randomized controlled trials, continuous evaluation of existing projects is critical. If the prevalence of HIV is very low in an IDU population under investigation, HIV seroconversion is not a reliable marker to detect blood-borne transmission. Like in our 1990–93 cohort, the incidence of HIV remained very low in the 1997–2005 cohort, and no new cases were detected after 1999.

We and others^[20,21] have used HBV and HCV as surrogate markers of the potential risk of spreading HIV. It is obvious that HBV immunization can confound the incidence of HBV and affect its usefulness as a surrogate marker. HCV is not effectively transmitted sexually and thus mainly reflects the injection risk, making this virus a more suitable marker of blood transmission.

Following our previous evaluation in 1990–1993, HBV immunization was introduced for unexposed NEP participants, which led to a sharp decline in HBV incidence from 11.7/100 to 3.36/100 pyr.

Our high HCV incidence is alarming (Table 2) and agrees with our previous results and those of others[22–24]. Several reasons may contribute to this phenomenon including the effects of a higher viral load and greater physical virion stability of HCV compared to HIV,^[25,26] as well as the much higher background prevalence of HCV among IDUs. Prevention of HCV transmission among IDUs is indeed a challenge, as demonstrated by a meta-analysis of 18 studies,^[27] which showed that neither NEPs nor MMT affected the incidence of HCV in IDUs. Researchers in the Netherlands recently found that only a combination of low-threshold NEPs and MMT could reduce HCV transmission among IDUs.^[28]

The majority of the participants in the Malmö NEP in 1997–2005 were already infected with HCV at baseline. Furthermore, we found that older age and longer duration of intravenous drug use was associated with HCV infection, and mixed use of heroin and amphetamine and incarceration prior to NEP enrolment were independent risk factors for HCV infection. Our data also show that most cases of HCV seroconversion occurred during the first year after enrolment, which is earlier than reported by Hagan et al.^[29]

Retrospective assessment of HCV RNA in frozen key samples from the longitudinal cohort revealed viraemia in 37/332 (12%) of the subjects who were anti-HCV negative at the time of enrolment. In an additional 30 individuals, a viraemic window-phase sample preceded anti-HCV seroconversion. Thus, it is likely that PCR analysis performed prospectively in anti-HCV-negative NEP participants would be a better method for detecting incident cases of HCV infection, permitting earlier and more effective interventions and tracing of transmission chains among such subjects.

After the initial phase of high HCV incidence following enrolment, new HCV infections became rarer in those still susceptible –a phenomenon which could be due both to behavioural and immunological factors.^[30]

Our study has limitations. Only NEP participants who were fully identified could be followed, which might have affected the results. However, demographic data reported by identifiable and nonidentifiable subjects were similar. Subjects with only one serum sample available had a higher risk profile compared to those in the longitudinal cohort, but they usually paid single or very few visits to the NEP making it questionable whether they should be regarded as NEP participants. Prospective assessment and monitoring of changes in drug injection risk profile was not consistently documented, nor were sexual risk factors. Furthermore, we were unable to objectively determine exact periods of and reasons for interruptions in NEP participation (e.g. imprisonment, travel or admission to detoxification clinics), and whether such interruptions were associated with changes in the rates of HCV seroconversion.

The effectiveness of a NEP depends on several factors, which, in addition to the number of needles and syringes exchanged,^[31] include acceptance and accessibility by the target population, as well as provision of adequate health education and medical services. In the Malmö NEP, limited opening hours and an age requirement of ≥20 years for participation may have been counterproductive, whereas the broad range of services offered probably had the opposite effect. A major advantage of NEPs is the possibility for surveillance of HIV seroepidemiology among IDUs and provide early warning as illustrated by the outbreak of HIV that occurred in 1994 in Vancouver,.^[32,33]

In conclusion, the persistently low incidence of HIV in the cohort we studied may be explained by a protective effect of the NEP combined with low background prevalence of HIV. Although NEPs conducted under these circumstances do not affect the incidence of HCV, they do contribute to surveillance and control of HIV transmission in the target population. Molecular testing focusing on participants with anti-HCV-negative samples may offer improved means of case finding.

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Treatment of patients with genotype 3 chronic hepatitis C- current and future therapies

Liver International

Special Issue: Proceedings of the 5th Paris Hepatitis Conference. International Conference of the Management of Patients with Viral Hepatitis: Special Edition Hepatitis C

Volume 32, Issue Supplement s1, pages 141–145, February 2012

Review Article

Shiv K. Sarin, Chandan K. N. Kumar

Article first published online: 29 DEC 2011

DOI: 10.1111/j.1478-3231.2011.02715.x

© 2012 John Wiley & Sons A/S

Abstract

Genotype 3 is a common type of HCV infection, and standard therapy using pegylated interferon (PEG-IFN) and ribavirin (RBV) is quite effective in these patients. While a short course of 16 weeks may result in comparable end of therapy responses, relapse rates are often high. A 24-week course is therefore preferable, and is expected to result in sustained virological response (SVR) rates of more than 70%. The 24-week course is especially recommended in the presence of steatosis (often associated with Genotype 3 infection), fibrosis stage two or more, high BMI and high viral load. In patients who do not achieve a rapid viral response (RVR) with combination therapy, an extended course up to 48 weeks should be considered. While not as definite as for genotype 1 patients, the presence of the CC variant of IL28b could help in the initial prognosis and the need for additional treatment, if an RVR is not achieved. The role of directly acting antiviral agents (DAA) has not been fully evaluated in treatment naïve, non-responders and relapsers in genotype 3 patients. Initial results with the cyclophilin inhibitor Debio-025 are quite encouraging. There is an urgent need for large clinical trials using DAA and host modulators in patients with G3 infection.

According to WHO, around 130–170 million people are chronically infected with the hepatitis C virus (HCV) worldwide, reflecting the magnitude of this global health burden [1]. The estimated prevalence is around 2%. Epidemiological surveys have also shown a geographical variation in the prevalence and distribution of hepatitis C genotypes worldwide. Although HCV genotype 1 predominates in the Western countries, genotype 3 accounts for 35–80% of chronic HCV infections in regions such as the Indian subcontinent [2], Southeast Asia and Australia [3].

The standard of care (SOC) therapy for patients with chronic HCV infection has been the combination of peginterferon (PEG-IFN) and ribavirin (RBV). These drugs are administered for either 48 weeks (HCV genotypes 1, 4, 5 and 6) or 24 weeks (HCV genotypes 2 and 3), inducing sustained virological response (SVR) rates of 40–50% in those with genotype 1, and of 80% or more in those with genotypes 2 and 3 infections [4]. However, the rates of SVR in patients infected with genotype 3 are lower than those with genotype 2 [5]. Second, compared with other genotypes, genotype 3 is associated with a higher incidence of hepatic steatosis and the rapid progression of liver fibrosis [6]. We have previously shown that the median rate of the progression of fibrosis per year is 0.25 (0.0–1.5) fibrosis units in patients with genotype 3 in India and higher in patients who acquire infection after 30 years of age. The median time for progression to cirrhosis was 16 years [7]. According to a recent meta-analysis, the odds ratio for the association of genotype 3 infection and accelerated progression of liver fibrosis was 1.52 in single biopsy studies suggesting faster fibrosis progression compared with other genotypes [8].

In a retrospective study of 353 patients, Nkontchou et al. [9] showed that hepatitis C genotype 3 was associated with a higher incidence of hepatocellular carcinoma (HCC) in patients with ongoing cirrhosis. The risk factors for an increased risk of HCC were male gender, older age, higher body mass index, low platelet count and genotype 3. Probably because of the rapid progression to fibrosis, genotype 3 could predispose to HCC along with other defined risk factors. The HCV genotype 3 core protein causes steatosis [10, 11, 12] that can lead to oxidative stress and reactive oxygen species predisposing to carcinogenesis [13, 14]. Thus, better treatment must be found for this dreadful yet curable infection.

Present treatment for hepatitis C genotype 3

According to the recent AASLD guidelines [15], PEG-IFN α-2b (1.5 μg/kg/week) plus RBV (800–1400 mg/day) or PEG-IFN α-2a (180 μg/week) plus RBV (800 mg/day) for 24 weeks are the established SOC regimens for patients with chronic hepatitis C genotype 2 or 3. However, optimal administration of PEG-IFN/RBV, in particular, the duration and the dosage have still not been clearly established in relation to outcome in rapid and slow responders. Based on the concept of ‘response guided treatment,’a recent meta-analysis evaluated the issue of decreasing the duration of treatment to improve tolerance and cost effectiveness, and most importantly to decrease viral resistance to the standard bitherapy [16]. Treatment with PEG-IFN and weight-based RBV for 16 weeks in patients a with rapid virological response (RVR) resulted in an SVR of 76.3% and 86.4% with 24 weeks of treatment, unlike genotype 2 which was 83.8% and 89.3% respectively. This was because of increased relapse rates in patients with genotype 3. Manns et al. [17] showed that the relapse rate was 26% after 16 weeks of treatment and 18% after 24 weeks in genotype 3 patients. The increased relapse rates could be because of steatosis, and as already mentioned, the increased rate of fibrosis in thes patients. In a cohort of 932 treatment-naïve patients, investigators of the ACHIEVE-2/3 trial [18] showed that hepatic steatosis significantly increases the risk of relapse independent of HCV RNA levels in patients with genotype 3 who achieve an RVR with IFN-based regimens. This may be because of altered IFN-α signalling, increased intrahepatic RNA levels or increased quasispecies diversity. Other known risk factors for relapse are male gender, black race, age over > 40, increased viral load, presence of fibrosis, body weight > 85 kgs and presence of diabetes mellitus.

Predictors of response

IL28b polymorphism

There is recent evidence suggesting that polymorphisms near the IL28b gene, which codes for interferon (IFN)-λ3, predict response to PEG-IFN-α and RBV treatment in HCV genotype 1 infected patients. However, several studies have shown that this pathway is also applicable to genotype 3 patients and can help predict those who can achieve RVR. The single nucleotide polymorphism (SNP) rs12979860 (CC/CT/TT) is located 3 kb upstream of the IL28B gene on chromosome 19, which codes for IFN- λ3, and rs8099917 (TT/TG/GG) SNP is located 8 kb downstream of the IL28B gene and 6 kb upstream of the IL28A gene, which codes for IFN- λ2. Moghaddam et al. [19] found that factors that predicted RVR were IL 28B SNPs rs12979860 (CC allele), rs8099917 (TT allele), age < 40 years old and viral load (< 4 × 10^5 IU/ml). This was not associated with an SVR because of the increased rate of relapse with the CC allele along with higher pretreatment viral loads and ALT levels. Thus, the ‘host responder genotypes’, namely the rs12979860 CC allele and the rs8099917 TT allele were more likely to relapse after an early response. This is in contrast to the genotype 1 response in which host–responder genotypes are associated with a RVR and SVR as well as a decreased rate of relapse. Lindh et al. [20] studied the association between the IL28B gene variation at rs 12979860 and viral kinetics observed during treatment of chronic hepatitis C in a cohort of 345 treatment-naïve chronic hepatitis C patients (241 patients with genotype C). Viral response kinetics were assessed using viral RNA levels at days 0, 3, 7 and 29. The first phase of viral decline was a change in RNA levels from baseline to day 3. The decline rate for the second phase i.e. the slope, was calculated using HCV RNA values from days 3 and 7 in patients who were HCV RNA negative on day 29, and values from days 3, 7 and 29 for the remaining patients. This study found that the IL28b CC allele was strongly associated with a rapid early phase viral decline by a median of 5.68 log₁₀ IU/ml compared with 4.82 and 4.62 log₁₀ IU/ml in patients with CT or TT at rs12979860 respectively. Thus, the patients with a CC allele had a better chance of achieving an RVR (67%) than those with the CT (60%) or TT alleles (47%). In patients who received 24 weeks of antiviral treatment, the probability of achieving an SVR in those who did not achieve an RVR, was higher in those with the CC allele (74%) than with the CT (59%) or TT alleles (29%). Mangia et al. [21] reported that IL28B influenced treatment outcome in patients who did not achieve an RVR, with SVR rates of 29%, 67% and 87% in patients carrying the TT, CT or CC alleles at rs12979860 respectively. Another important conclusion of the study by Lindh et al. was that even though the IL28B CC allele was associated with a rapid early viral decline, it was not associated with an SVR when patients received a short course of 12 weeks of treatment. This was because of the high baseline viral load that is frequently observed in these patients. However, in a group with a baseline HCV RNA of 5.6 log₁₀ IU/ml, 33/38 patients (87%) treated for 12 weeks achieved an SVR if they carried the CC or CT SNP rs12979860 genotypes. As part of the lead-in phase of the HALT-C trial, Freedman et al. [22] showed fascinating evidence that the consumption of three or more cups of coffee per day was an independent predictor of response to standard bitherapy in chronic HCV patients. After adjustment for other predictors of response such as age, ethnicity, alcohol, cirrhosis, IL28b polymorphism rs12979860, the odds ratio for coffee drinkers vs non-drinkers was 2.0 for a response at week 12, 2.1 for a response at week 20, 2.4 for a response at the end of treatment and 1.8 for SVR.

(Click on picture to enlarge)

Other predictors of response

In a recent retrospective study by Amanzada et al. [23], a subgroup of patients with genotype 3, who were under the age of 40, who had an ‘ultrarapid’ virological response within 2 weeks (HCV RNA undetectable at week 2 of treatment), low ƴ-GT/ALT ratios and an absence of steatosis on liver biopsy, were found to achieve an SVR with IFN-α2A monotherapy 3–6 Million Units (MU) either daily or three times a week. Neither IL28b SNPs rs12979860 or rs8099917 genotypes, nor the duration therapy (24 weeks vs. 48 weeks) were related to treatment outcome. Moreover, this treatment was better tolerated because of the absence of the adverse effects of RBV. However, further randomized controlled trials are needed to validate these findings. A summary of the other predictors of response to standard treatment in chronic hepatitis C genotype 3 are given below (Table 1).

Future treatment options for patients with genotype 3

HCV is a 9.6-kb positive-sense, single-stranded RNA virus. It encodes a large single open reading frame corresponding to a poly-protein precursor of about 3000 amino acids, which is proteolytically processed by cellular signal peptidases and HCV-encoded proteases into at least 10 individual proteins, in the order of C-E1-E2-p7-NS2-NS3-NS4A-NS4B-NS5A-NS5B. Newer antivirals, more commonly known as directly acting antivirals (DAA), have mainly focused on two viral proteins, the NS3-4A serine protease and the NS5B RNA-dependent RNA polymerase, both of which have enzymatic activities essential for viral replication [24]. The peptidomimetic inhibitors of the NS3/4A serine proteases, telaprevir (VX-950) and boceprevir (SCH-503034) have created a revolution in the treatment of genotype 1 and have recently been recommended in combination with the standard bitherapy PEG-IFN/RBV for the treatment of patients with chronic hepatitis C genotype 1 [4]. However, these drugs have not shown to be of great benefit in the treatment of patients with genotype 3.

An alternative strategy is to target host factors that are also required for viral replication. Cyclophilins are a family of cellular peptidyl-prolyl isomerases required for HCV replication [25]. In an in vitro study by Mathy et al., combinations of a host factor (cyclophilin) inhibitor, NIM811, were studied with the three main classes of virus specific inhibitors: BILN2061 (ciluprevir), first NS3-4A protease inhibitor, a non-nucleoside NS5B polymerase inhibitor thiophene-2-carboxylic acid, and NM107, the active moiety of NM283 (valopicitabine), the first nucleoside NS5B inhibitor. Based on mathematical modelling, the effect of these combinations was shown to be synergistic for NIM811 with a nucleoside or a non-nucleoside viral polymerase inhibitor and additive for NIM811 with a viral protease inhibitor. The key advantages of targeting host factors are long lasting antiviral response and a greater genetic barrier to the emergence of viral escape mutants. The use of the oral cyclophilin B inhibitor Debio-025 was first investigated in a randomized double blind, placebo controlled trial of 19 patients co-infected with HIV and HCV [26]. Of the 19 co-infected patients, those treated with Debio-025 1200 mg twice daily for 15 days (n = 16) experienced a significantly greater maximum reduction of log₁₀ HCV RNA copies/ml (only in genotypes 1, 3 and 4) than placebo treated (n = 3) patients. The least squares mean of the maximum reduction of log₁₀ HCV RNA copies/ml for the Debio-025 group was −3.63 compared with −0.73 in the placebo group. The greatest response was observed in patients with genotype 3 who achieved a least squares mean maximum reduction of log₁₀ HCV RNA copies/ml of −4.46 log₁₀. None of the patients developed a viral breakthrough in the treatment arm, and time to relapse varied after the end of treatment. This was the first study to show the antiviral effects of oral cyclophilin inhibitors in a clinical study; however, larger studies are needed before this regimen can be clinically recommended. Another group of host factors was studied by Lupberger et al. [27]. The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase (RTK) that regulates a number of key processes, including cell proliferation, survival and differentiation during development, tissue homeostasis and tumorigenesis.

Ephrin receptor A2 (EphA2) mediates cell positioning, cell morphology, polarity and motility. HCV entry is a multistep process involving viral envelope glycoproteins and host cell factors. Attachment of the virus to the target cell is mediated through binding of HCV envelope glycoproteins to glycosaminoglycans. HCV is internalized in a clathrin-dependent endocytic process requiring CD81, scavenger receptor type B class I (SR-BI), claudin-1 (CLDN1) and occludin (OCLN). Inhibition of EGFR or EphA2 activity reduced CD81-CLDN1 association, hence hampering the cell entry process of HCV. The in vitro results showed that EGFR or EphA2 inhibition was associated with decreased cell entry, fusion, cell-to-cell transmission and subsequently decreased viral spread. This was extrapolated in in vivo studies conducted using an erlotinib (EGFR inhibitor) chimeric urokinase plasminogen activator–severe combined immunodeficiency (uPA-SCID) mouse model. Its treatment decreased steady-state HCV RNA levels by more than 90%. However, viral load increased, once the treatment was discontinued. Treatment was well-tolerated and did not induce any marked changes in safety parameters such as serum concentrations of alanine transaminase, albumin or body weight. These fascinating results provide a glimmer of hope, although there is a long way to go before they can be recommended in patients with chronic hepatitis C. There are many drugs in the pipeline, some of which are being studied in phase III trials (Table 2).

Conflicts of interest

The authors declare no conflicts of interest.

References

Source