Tuesday, 19 July 2016

Twin epidemics of new and prevalent hepatitis C infections in Canada: BC Hepatitis Testers Cohort

Twin epidemics of new and prevalent hepatitis C infections in Canada: BC Hepatitis Testers Cohort

Naveed Zafar JanjuaEmail author, Amanda Yu, Margot Kuo, Maria Alvarez, Darrel Cook, Jason Wong, Mark W. Tyndall and Mel Krajden BMC Infectious DiseasesBMC series – open, inclusive and trusted201616:334 DOI: 10.1186/s12879-016-1683-z © The Author(s). 2016

Received: 12 January 2016 Accepted: 13 June 2016 Published: 19 July 2016
Open Access Full Text - BMC Infectious Diseases

Abstract
Background

We characterized the twin epidemics of new and prevalent hepatitis C virus (HCV) infections in British Columbia, Canada to inform prevention, care and treatment programs.

Methods
The BC Hepatitis Testers Cohort (BC-HTC) includes individuals tested for HCV, HIV or reported as a case of HBV, HCV, HIV or active TB between 1990–2013 linked with data on their medical visits, hospitalizations, cancers, prescription drugs and mortality. Prevalent infection was defined as being anti-HCV positive at first test. Those with a negative test followed by a positive test were considered seroconverters or new infections.

Results
Of 1,132,855 individuals tested for HCV, 64,634 (5.8 %) were positive and an additional 3092 cases tested positive elsewhere for a total of 67,726. Of 55,781 HCV positive individuals alive at the end of 2013, 7064 were seroconverters while 48,717 had prevalent infection at diagnosis. The HCV positivity rate (11.2 %) was highest in birth cohort 1945–1964 which declined over time. New infections were more likely to be male, 15–34 years of age (born 1965-1984), HIV- or HBV-coinfected, socioeconomically disadvantaged, have problematic drug and alcohol use and a mental health illness. The profile was similar for individuals with prevalent infection, except for lower odds of HBV-coinfection, major mental health diagnoses and birth cohort >1975.

Conclusions
The HCV positivity rate is highest in birth cohort 1945–1964 which represents most prevalent infections. New infections occur in younger birth cohorts who are commonly coinfected with HIV and/or HBV, socioeconomically marginalized, and living with mental illness and addictions.

KeywordsHCV Hepatitis B HIV Epidemiology Screening Cohort study

Discussion Only
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We used a large cohort of more than one million people tested for HCV in BC, and while accounting for mortality, we found that a large number of people are currently living with HCV. The highest positivity rate was among people born in 1945-64, which declined over time and was lowest in 2013. New infections were detected mainly among younger age groups. The new HCV infection (seroconversion) rate was highest among males, those with HIV or HBV co-infection, mental health conditions, problematic alcohol or illicit drug use, and socioeconomically disadvantaged persons. Prevalent HCV infection was associated with being male, born 1945-64, HIV co-infected, problem alcohol and illicit drug use, and socioeconomic deprivation. These findings of twin epidemics highlight important opportunities for prevention, testing and treatment of HCV.

In this analysis, we identified two groups of HCV infected individuals: new infections (seroconverters) and those with prevalent HCV infection. Most of those with prevalent HCV were born 1945-1964, while most newly infected individuals were younger. However, the seroconverters are not a homogeneous group: 24-month seroconverters differed from >24 months seroconverters in terms of age, sex, testing patterns, and HBV co-infection rate. Surveillance data on acute HCV infections indicate that 70 % of seroconverters reported injection drug use in the past 12 months [18]. In a BC-HTC subset for whom self-reported risk factor data was available, 85 % of those who self-reported injection drug use had a medical visit for illicit drug use. Thus, 24-month seroconverters most likely acquired HCV through their injection drug use networks.

Most of the HCV cases, especially prevalent infections, were identified among those born 1945-64 and the positivity rate was much higher in this group, especially for those born 1950-1960. Similarly high 1945-64 birth cohort positivity rates have been reported in various studies from the United States [19, 20, 21, 22]. Using reported HCV cases in Canada, Trubnikov et al. found the highest HCV prevalence among the 1950-54 and 1955-59 birth cohorts, followed by 1960-64 and 1966-69, while prevalence among those born 1945-49 was lower than for those born 1965-69 [2]. In contrast, in our study, the positivity rate for birth cohort 1945-49 was higher than for birth cohort 1965-69 (Fig. 2). Our findings are also consistent with a study which assessed HCV related hospital admissions where the 1950-54 and 1955-59 birth cohorts had the highest rates [23]. Although the positivity rate is still highest among the 1945-64 birth cohort, the rate in this cohort has been declining over successive years suggesting a decreasing pool of undiagnosed prevalent HCV infections. Canada has had risk based testing guidelines since 1994 [24]. The declining positivity rate in this birth cohort suggests that testing driven by risk based guidelines have been able to identify most people with current or past risk activities and diagnose most of the HCV infections in this cohort. However, risk based testing may not identify individuals who are unable to recall or are unwilling to disclose remote risk behaviors. The US Preventive Services Task Force has recommended one time testing of individuals born 1945-65 [22]. Further studies on feasibility and cost effectiveness of various strategies are needed to identify undiagnosed infections in BC.

Risk factors for both new and prevalent HCV infections were similar with some notable exceptions, including age, birth cohort, drug use, HBV co-infection and mental health diagnoses. HBV co-infection and mental health problems were significantly associated with increased odds of new infection but decreased odds of prevalent HCV infection, while ORs for illicit drug use compared to no drug use among new infections (AOR = 21) were four times than those for prevalent HCV infection (AOR = 5.0). ORs for prevalent HCV infection were highest for birth cohort 1945-64 and declined thereafter, while among new infections, ORs were highest for those born later, consistent with an earlier analysis demonstrating a higher HCV incidence rate in younger birth cohorts [25]. Demographic characteristics and risk factors for prevalent HCV were also consistent with recent data from the United States and Canada [8, 20]. Likewise, in a recent electronic medical record based study from the US, being a baby boomer, male, people who injects drugs (PWID), HIV co-infected and having low income were associated with HCV positivity [26]. Risk factors among new infections were also similar to those identified with HCV infection in high risk populations, mainly PWID. Among seroconverters especially 24-months seroconverters, those born 1965-84, HIV/HBV co-infection, socioeconomic deprivation, mental illness, illicit drug use and problematic alcohol use were more common than among prevalent HCV infections (Table 1/Fig. 1). These findings highlight the presence of syndemics of blood-borne infections (BBI), mental illness, addiction, and socioeconomic marginalization in this population as has been reported by others [27, 28, 29]. Addressing these syndemics requires comprehensive services including integrated testing, prevention and treatment for STI/BBIs, as well as mental health and addiction services to address the needs of this population group.

Findings from this paper should be interpreted in the context of some methodological issues. The validity of our estimates depends on the successful linkage rate. Linkage rates were very high for HCV (>85 %), especially in recent years [14]. Linkage rates for those HIV co-infected were much higher than the overall HIV linkage rate, especially before 2005. Thus, the HIV co-infection rate may have been underestimated. However, as reported earlier, we used multiple sources of HIV status identification to reduce underestimation. In this study, we did not have access to immigration and Aboriginal status data and hence we were not able to characterize the disease burden among immigrants and Aboriginal populations. Other data suggest that Aboriginal people are five times more likely to be infected with HCV [30]. Immigrants from endemic countries are also more likely to have higher HCV infection rates.

To date, laboratory testing for HCV has followed risk based guidelines and hence a higher positivity rate among HCV testers in this cohort is expected compared to the general population. However, general population surveys such as the Canadian Health Measures Survey may not capture high risk populations with higher HCV prevalence thus and may underestimate total population of infected individuals [8, 20]. Categorizing prevalent infections based on being positive at the first test may be an over-estimate as some of these individuals are likely to be recent seroconverters as shown in our recent molecular analysis [31]. The prevalent HCV case detection could be affected by presence of late stage symptomatic disease or survival. Survival may also affect the difference in risk factor profile between prevalent and new cases. In the BC-HTC, data is available on all cohort members many years before cohort initiation to assess risk factors as presented in Table 1. Thus, for all cohort members regardless of first test or diagnosis date, data on risk factors started at the same time, providing ample time to assess risk factors from the available data. Furthermore, after accounting for mortality in the cohort, there was no difference in identified risk factor patterns in models including both currently alive and dead and only those currently who are currently alive. Thus, survival bias is unlikely to explain difference in risk factor profile between prevalent and new infections. However, survival bias is not expected to be completely eliminated especially in early nineties, when people could have died before HCV diagnosis or getting diagnosed because of symptoms related to late stage disease. In another analysis, we found that late HCV diagnosis in relation to advance stage liver disease (hepatocellular carcinoma and decompensated cirrhosis) was common in early nineties and have declined substantially over time [32].

In the current paper, data on RNA testing and active infection was not presented, which is important to assess people living with active infection and need treatment to prevent progressive liver disease. The BC-HTC provides a platform to assess program progress through cascade of care monitoring, long term outcomes related to HCV and impact of treatment on long term outcomes. These data are in the process of being analyzed and will be presented in future reports.

Conclusions
The HCV positivity rate was highest in the 1950-54 and 1955-59 birth cohorts and overall among those born between 1945- 1964, which declined over time. Furthermore, the year over year decline in the positivity rate suggests that most of the HCV infections in these cohorts have already been identified. However, current risk based testing may not identify individuals who are unable to recall or are unwilling to disclose remote risk behaviors. Further studies are needed to estimate the number of undiagnosed HCV infection and assess optimal strategies to identify the remaining undiagnosed infections. Newly acquired infections are occurring mainly in younger birth cohorts and these groups are more likely to be co-infected with HIV and/or HBV, socioeconomically marginalized, and living with serious mental illnesses and addictions. Comprehensive syndemic approaches that take into account co-infections, mental health, additions and socioeconomic vulnerabilities are urgently required to identify, treat, and support people with HCV infection.

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Liver diseases exhibit differing patterns in ethnic minorities

Liver diseases exhibit differing patterns in ethnic minorities

Chronic liver disease (CLD) and cirrhosis are serious liver conditions but little is known about how they affect ethnic minority populations in the United States. When researchers examined CLD and cirrhosis among different groups, they found that the prevalence of CLD ranged from 3.9 percent in African Americans and Native Hawaiians to 4.1 percent in whites, 6.7 percent in Latinos, and 6.9 percent in Japanese.

Nonalcoholic fatty liver disease (NAFLD) was the most common cause of CLD in all ethnic groups combined (52 percent), followed by alcoholic liver disease (ALD) (21 percent).
NAFLD was the most common cause of cirrhosis in the entire study, and by ethnicity, it was also the most common cause of cirrhosis in Japanese Americans, Native Hawaiians, and Latinos, accounting for 32 percent of cases. ALD was the most common cause of cirrhosis in whites (38.2 percent), while hepatitis C virus was the most common cause in African Americans (29.8 percent).

"This is the first study of its kind to include Native Hawaiians and Japanese Americans, and it revealed the important discovery that NAFLD is the most common cause of CLD and cirrhosis in Japanese Americans, Latinos, and Native Hawaiians and that NALFD prevalence in Japanese is higher than in Latinos and other ethnic groups," said Dr. Veronica Wendy Setiawan, lead author of the Hepatology study. "This paper addresses the gap in knowledge for understudied populations with respect to CLD's underlying etiology and underscores NAFLD as the most important cause of CLD. It also highlights the need to implement improved screening, diagnostic, and management approaches to face this growing epidemic."

http://dx.doi.org/10.1002/hep.28677

Monday, 18 July 2016

Liver tissue model accurately replicates hepatocyte metabolism, response to toxins

Liver tissue model accurately replicates hepatocyte metabolism, response to toxins

Microfluidic device may help predict toxic effects of new drugs, study liver disease

Massachusetts General Hospital

A team of researchers from the Massachusetts General Hospital (MGH) Center for Engineering in Medicine (MGH-CEM) have created a "liver on a chip," a model of liver tissue that replicates the metabolic variations found throughout the organ and more accurately reflects the distinctive patterns of liver damage caused by exposure to environmental toxins, including pharmaceutical overdose. Their report has been published online in the journal Scientific Reports.

"Our goal with this project was to create a liver tissue construct that responds to toxins the same way the liver in your body does," says William McCarty, PhD, a postdoctoral fellow at MGH-CEM and the paper's lead author. "The liver is a chemical processing plant, but it's not a single vat; different locations within the liver react differently to drugs and toxins. Here, we exploited microfluidics to control the metabolism of liver cells down to a resolution of a few cells, allowing us to create liver tissue that shows the same patterns of toxicity caused by differences in drug metabolism as the liver in your body."

When blood passes through the liver, it travels from arteries to veins through channels called sinusoids, lined with the liver cells called hepatocytes. From one end of the sinusoid to another, the hepatocytes have different metabolic functions, often controlled by external factors and gene expression. For example, the cells closest to the arterial end of the sinusoid are most efficient at releasing glucose that has been stored in the form of glycogen, while cells at the venous end are most efficient at taking up and storing glucose. Similar differences for other liver functions are well known, with metabolic changes occurring across the 25-cell length of the sinusoid.

In order to develop a system that more closely replicates the metabolic differences among hepatocytes, the research team developed a microfluidic device that distributes hormones or other chemical agents across a 20- to 40-cell-wide sample of hepatocytes in such a way that the effects on the liver cells vary from one side to the other. For example, if blood-sugar-lowering insulin is fed into one of the device's two inlets while glucagon, which raises blood sugar, is added through the other, the metabolism of the hepatocytes is changed so that those on one side release glucose while those on the other take it up. The use of other agents produced similar results across the field of hepatocytes regarding nitrogen metabolism or alcohol degradation, and use of a molecule that induces the expression of drug metabolism enzymes resulted in varied zones of susceptibility to the toxic effects of acetaminophen.

"Investigators have been developing in-vitro liver models for 40 years, but all of those systems ignore the distinct patterns of metabolically active hepatocytes that exist within the liver sinusoid" says Martin Yarmush, MD, PhD, director of the MGH-CEM and the paper's senior author. "We hope this tool, which displays zonation of carbohydrate and nitrogen metabolism, in addition to drug detoxification and alcohol degradation, will improve our ability to understand and predict the effects of toxins and new drugs on the liver."

Co-author Berk Usta, PhD, of MGH-CEM, adds, "While further replication and validation using more compounds are needed, this study demonstrates the importance of fine control of liver metabolism. Since many liver pathologies also show regional variation, this tool may also serve as a basis for models of liver disease." Berk and Yarmush are both members of the Harvard Medical School faculty. The work in this study was supported by National Institutes of Health grants UH2TR000503, F32DK098905 and 1R21EB020192-01.

Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The MGH Research Institute conducts the largest hospital-based research program in the nation, with an annual research budget of more than $800 million and major research centers in HIV/AIDS, cardiovascular research, cancer, computational and integrative biology, cutaneous biology, human genetics, medical imaging, neurodegenerative disorders, regenerative medicine, reproductive biology, systems biology, photomedicine and transplantation biology. The MGH topped the 2015 Nature Index list of health care organizations publishing in leading scientific journals, earned the prestigious 2015 Foster G. McGaw Prize for Excellence in Community Service and returned to the number one spot on the 2015-16 U.S. News & World Report list of "America's Best Hospitals."


Sunday, 17 July 2016

Treatment of Chronic Hepatitis C in the Aged – Does It Impact Life Expectancy? A Decision Analysis

Treatment of Chronic Hepatitis C in the Aged – Does It Impact Life Expectancy? A Decision Analysis

Yaakov Maor ,Stephen D. H. Malnick, Ehud Melzer, Moshe Leshno
PLOS Published: July 13, 2016
• http://dx.doi.org/10.1371/journal.pone.0157832
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Abstract
Background and Aims
Recent studies have demonstrated that the efficacy of interferon-free direct-acting antiviral agents (DAAs) in patients over 70 is similar to that of younger age groups. Evidence continues to mount that life expectancy (LE) increases with successful treatment of hepatitis C (HCV) patients with advanced fibrosis. The evidence in older people is more limited. Our aim was to estimate the life year (LY) and quality-adjusted life year (QALY) gained by treatment of naïve patients with HCV as a function of patient's age and fibrosis stage.

Methods
We constructed a Markov model of HCV progression toward advanced liver disease. The primary outcome was LY and QALY saved. The model and the sustained virological response of HCV infected subjects treated with a fixed-dose combination of the NS5B polymerase inhibitor Sofosbuvir and the NS5A replication complex inhibitor Ledipasvir were based on the published literature and expert opinion.

Results
Generally, both the number of LY gained and QALY gained gradually decreased with advancing age but the rate of decline was slower with more advanced fibrosis stage. For patients with fibrosis stage F1, F2 and F3, LY gained dropped below six months if treated by the age of 55, 65 or 70 years, respectively, while for a patient with fibrosis stage F4, the gain was one LY if treated by the age of 75. The QALY gained for treated over untreated elderly were reasonably high even for those treated at early fibrosis stage.

Conclusions
There is a significant life expectancy benefit to HCV treatment in patients up to age 75 with advanced-stage fibrosis.

Introduction
Hepatitis C (HCV) affects about 170 million people worldwide and is a leading cause of cirrhosis and hepatic insufficiency, and a reason for liver transplantation. In addition it accounts for more than 50% of incident hepatocellular carcinoma (HCC). The U.S. Centers for Disease Control and Prevention (CDC) and the U.S. Preventive Services Task Force (USPSTF) recently issued their recommendation for one-time testing of adults born during 1945–1965 (baby boomers) for HCV without prior ascertainment of HCV risk [1]. These recommendations, which are based on the finding that the members of this cohort, many of whom are now approaching 70, account for 76.5% of those with HCV antibodies in the US [1], led to the development of a multicohort natural history model for predicting disease outcomes and benefits of therapy [2]. The model projected a decline in the prevalence of HCV by 2030. However, it also predicted that the proportion of cases with advanced fibrosis will continue to rise during the next two decades, with the number of cases of cirrhosis and hepatic decompensation peaking after the year 2020. The study further predicted that the age of those with cirrhosis and its complications will continue to rise, with those aged 60 to 80 being most affected. As this age group overlaps the 1945–1965 birth cohorts, more advanced HCV can be seen as becoming a serious problem for the elderly.

In previous studies reported in the literature, the older population was largely excluded from the pivotal phase III registration trials of the first generation protease inhibitors and of interferon-free direct-acting antivirals (DAAs) [39]. Therefore, there are no guidelines for treatment of the elderly, defined as 70 years and older, a definition that is largely driven by the age limit in the major phase III trials. Recent observational studies have demonstrated that the efficacy of the first generation protease inhibitor-based regimens in patients over 65 is similar to that for younger age groups, though adverse effects are more frequent [10]. Likewise, sub-group analysis on a small number of elderly patients included in the registration DAA trials show comparable efficacy, with a sustained virological response (SVR) exceeding 90% [79]. Although these regimens have a favorable safety profile they are costly, a consideration that may be prohibitive particularly in those parts of the world with a high prevalence of HCV.

Recently, it has been shown that the beneficial effects of SVR also result in reduced all-cause mortality in the high-risk population of patients with chronic HCV infection and severe hepatic fibrosis [1113]. The strongest evidence on the association between SVR and overall survival is a large Veterans Affairs cohort study that found SVR to be associated with a 30% to 50% reduction in mortality risk, after adjustment for many confounders [14]. As the median age of patients included in these studies was the late forties to the early fifties, the question whether elderly patients would actually benefit from HCV treatment with improved life expectancy (LE) remains open.

Our objective was to compare the estimated life years (LY) and quality-adjusted life years (QALY) using two strategies: treatment vs. no treatment of naïve patients with HCV as a function of patient's age and fibrosis stage in the U.S. population.

Materials and Methods
Model Construction
We constructed a Markov model of HCV natural history and progression toward advanced liver disease in order to assess LE and QALY. Markov models are employed to represent stochastic processes, that is, random processes that evolve over time. In a healthcare context, Markov models consider the patients in a discrete state of health, and the events represent the transition from one state to another. The possibility of modeling repetitive events and time dependence of probabilities and utilities associated permits an accurate representation of the evaluated clinical structure. The model of HCV natural history and the SVR of the currently approved DAA regimens were based on the literature. The model was developed in stages starting with a traditional bubble diagram of disease states that served as the basis for developing a more detailed mathematical model that followed the health state of HCV infected persons. We used cohort simulation with the following health states included: resolved infection, stage of fibrosis (F0 to F4 –cirrhosis) [15], liver failure, HCC, liver transplantation and liver-related deaths. Age-specific (non-liver) deaths were also included. In addition, we used Monte Carlo simulation to estimate the rate of HCC and liver transplantation.

Data Sources
Table A in S1 File gives the assumptions of the Markov model. Transition rates for progressing from one fibrosis stage to another stage, according to the METAVIR classification (F0→F1; F1→F2; F2→F3; F3→F4), were largely based on the pooled rates from a meta-analysis reported by Thein and colleagues [16]. The progression of fibrosis is an essential factor in the Markov model analysis. It is well known that the progression of fibrosis may differ between individuals. Several reports [1719] consistently demonstrate more rapid fibrosis progression rate for those over 50 than for those younger than 50. However, as data regarding the rate of fibrosis progression for HCV patients older than 70 are scarce, we considered a conservative linear mode of fibrosis progression in this age group. Likewise, compared with premenopausal women, postmenopausal women have more rapid fibrosis progression rate. We based our estimation of fibrosis rate on Thein et al [16], and used a base-case progression rate and a sensitivity analysis over a range of progression rates, which include rates applicable to postmenopausal women. Furthermore, the results of this study apply to a hypothetical average patient, but not to an individual person.

The SVR considered for the model was driven by two registration trials of the fixed-dose combination of the NS5B polymerase inhibitor Sofosbuvir and the NS5A replication complex inhibitor Ledipasvir in untreated HCV genotype 1 infection. We also included data derived from a sub-analysis of the treated elderly population included in these registration trials [7, 8]. This treatment combination was chosen since it represents the current acceptable SVR achieved by this and other approved all-oral DAA regimens for HCV genotype 1 in naïve patients.

Based on longitudinal studies in North America and Europe the annual risk of clinical decompensation, death or transplantation, and HCC has been estimated to be 6% (range, 4–8%), 3% (range, 2–6%), and 3% (range, 2–6%) per year, respectively [2022]. We also assumed that the 1-year mortality was 5.5% in compensated and 20% in decompensated cirrhotics [23] HCC risk in those with F3 fibrosis was estimated to be 10% of that in cirrhosis. Age-specific (all-cause) deaths derived from standard mortality tables [24].

Regression of fibrosis following SVR was estimated from large cohorts of HCV patients attaining an SVR [25, 26]. These cohorts were evaluated for the evolvement of fibrosis stage using liver biopsy [25] or non-invasive measures of fibrosis [26]. The follow-up post-treatment period in the latest report was up to 10 years [26]. In the case of cirrhosis we estimated some regression of fibrosis in 50% of patients following an SVR. It was assumed that cirrhotic patients with SVR who had a regression of fibrosis had no subsequent hepatic decompensation. The risk of progression from cirrhosis to HCC after SVR was estimated to be 0.66% per year [26, 27], whereas patients with F3 stage fibrosis who attained an SVR were considered not likely to develop HCC (for all assumptions used to for the Markov model see Table A in S1 File). Background mortality was based on U.S. life tables.

The primary end-point of the study was number of LY and QALY gained for treated vs. untreated naïve patients with HCV. In general, we considered at least six months LY gained as life expectancy sufficient to warrant treatment.
Sensitivity Analysis

Sensitivity analysis was performed to assess the extent to which the model’s calculations were affected by uncertainty in our assumptions. The ranges utilized in the sensitivity analysis were derived from the medical literature. Sensitivity analysis with tornado diagrams was utilized to rank the variables in the model with regard to their impact on LE (QALY). We then conducted one-way sensitivity analysis of the variables with high impact on LE (QALY).

Variables studied in the sensitivity analysis included: SVR (ranging from 0.8 to 0.99); annual rate of decompensation (ranging from 0.02 to 0.083); death rate for decompensated cirrhosis (ranging from 0.065 to 0.194); death rate for HCC (ranging from 0.33 to 0.86) and rate of HCC in decompensated cirrhosis (0.068 to 0.09).

Results
LY and QALY gained
LY gained for treated vs. untreated HCV patients ranged from 0.01 years for an 80-year-old with fibrosis level F1 to 10.20 years for a 40-year-old cirrhotic (Table 1). The actual life expectancy for treated vs. untreated HCV patients for each fibrosis stage is shown in Table B 1–4 in S1 File. Thus, for example, for a 65-year-old patient with fibrosis stage F3 the life expectancy is 81.420 years and 79.872 years for treated and untreated patients, respectively.

LY and QALY gained for treated vs. untreated HCV-infected patients were analyzed for each stage of fibrosis (F1 to F4) separately (Fig 1A–1D and Table 1). Generally, both the numbers of LY and QALY gained gradually decreased with advancing age but the rate of decline was slower with more advanced fibrosis level. In those patients with fibrosis stage F1, LY gained dropped below six months if treated by the age of 55, whereas for stages F2 and F3 LY gained was about six months if treated by the age of 65 or 70 years of age. A patient with fibrosis stage F4 gained more than one LY if treated for HCV by the age of 75. The QALYs gained for treated over untreated elderly were reasonably high even for those treated at an early fibrosis stage. As can be seen in Fig 1D, the curves of the LY and of the QALY merge for fibrosis stage F4, reflecting the diminished quality of life for patients with liver cirrhosis.

A Monte-Carlo simulation of 10,000 patients for projected rates of HCC and of liver transplantation in treated vs. untreated HCV patients is depicted in Tables 2 and 3, respectively. The rates are stratified by fibrosis stages F2, F3, F4 and by age, 50 or 70. As expected, the rates of HCC and of liver transplantation are higher with more advanced fibrosis stage. The rates are also higher in the 50-year-old group compared with the 70-year-old group, given the difference in life expectancy. Those patients treated for HCV demonstrate a significant decline in the rates of both HCC and liver transplantation. Nevertheless, the robustness of the reduction of the rate of both HCC and liver transplantation by anti-HCV treatment is diminished to a great extent among patients at the cirrhotic stage. However, among both the older and the younger patients, the extent to which complications are prevented in the treated population compared with the untreated population is similar.

Sensitivity analysis
Tornado sensitivity analysis was performed looking at several variables (Fig 2A and 2B). The increment in life expectancy gained among patients with F3 fibrosis stage aged 50 was compared with that among patients aged 70. The more significant increment in LE gained derived from improvement of SVR in the younger population. Increases in SVR rates from 80% to 99% for 50-year-olds, resulted in an increment of over one year of LE gained. With the same improvement in response in 70-year-olds, the survival benefit was only about two months.

Discussion
In this study we found a significant life expectancy benefit of HCV treatment in elderly patients with advanced stages of fibrosis that decreased with patient's age. Patients with fibrosis stages F2 and F3 met our threshold of a 6-month gain in LY if treated by the age of 65 and 70 years, respectively, and patients with cirrhosis had a gain of at least one LY if treated by the age of 75.

There are some limitations to our study. Data from previous studies [1719] demonstrate a more rapid fibrosis progression rate for those over 50 than for those younger than 50. Data regarding the rate of fibrosis progression for HCV patients older than 65 years are scarce. Therefore, our assumptions for patients older than 65 may lack accuracy and this may affect the predictive value of the model, notwithstanding Zhou et al [28], who reported that variation in rates of fibrosis progression had only a minimal impact on life expectancy gains.

Also, our model assumed similar baseline characteristics for treated and untreated patients, though real-life experience clearly shows that untreated patients differ from treated patients on many demographic and clinical parameters.
Several large studies have documented an overall survival benefit for those patients with HCV who attain an SVR.

A recent international, multicenter, longitudinal study with a long follow-up duration [11] showed SVR to be associated with prolonged overall survival and demonstrated a lower risk for all-cause mortality in patients with chronic HCV infection and advanced hepatic fibrosis who achieved SVR. The risk of all-cause mortality for patients without SVR was almost four times higher than that for patients with SVR. In another study of the association of SVR with all-cause death and liver transplantation as a combined end point among patients with advanced fibrosis or cirrhosis [12, 13], the adjusted cumulative proportion of patients who died or underwent liver transplantation after 7.5 years of follow-up was higher in patients not responding to peg-interferon and ribavirin therapy (27.2%) compared to patients with virological relapse (4.4%) or who achieved an SVR (2.2%).

The largest study reported in the literature, which followed up a predominantly male population of U.S. veterans with all stages of liver fibrosis for a median of 3.8 years, reported 5-year mortality rates of 6.7% to 8.0% in patients with SVR vs. rates of 14.4% to 24.4% in patients without SVR [14].

The fact that these studies, although encouraging, had patients in their forties and fifties as their target population imposes serious limitations on our ability to extrapolate their conclusions to older patients.
Zhou et al [28] concluded from their decision analysis of a population stratified into five age groups from 60 to 80 treated with first-generation protease inhibitor combinations that the greatest life expectancy benefit was for treatment of younger patients with higher levels of fibrosis.

Assuming an SVR rate of 70%, the mean life expectancy gained across all ages and stages of fibrosis was 2.18 years for women and 2.95 years for men, and all cohorts with fibrosis stage F2 and above reached a 6-month threshold of life expectancy gained. By and large these results concur with our analysis. Our analysis, however, was based on the results of more effective DAA regimens and included patients aged 40 to 80, thus enabling comparison of younger and older age groups.

Our analysis found additional advantages to HCV treatment as it resulted in a significant reduction in two of the major complications of advanced liver disease, namely HCC and the need for liver transplantation. However, unlike the advantage in life expectancy observed particularly in cirrhotic patients treated for HCV, reduction in both HCC and liver transplantation rates were more robust in those patients who had less advanced fibrosis (stages F2 and F3) than in the cirrhotic stage HCV. These observations are somewhat in conflict with the findings of van der Meer, et al [12], who reported in their long-term follow-up of patients with advanced fibrosis (F3-F4) that the risk of liver-related mortality or liver transplantation was negligible in those patients who attained an SVR compared with those who did not respond to anti-viral treatment, while the risk of HCC did not diminish completely even following successful treatment.

Our sensitivity analysis clearly demonstrated that higher SVR rates, which may be achieved with the new DAAs, will mainly affect the life expectancy of young rather than elderly patients. Zhou et al [28] also concluded that the older cohort did not realize substantial improvement in life expectancy gain despite the up to 90% increase in SVR. As the new interferon-free DAA regimens show a high safety profile, but carry a significant financial burden, one of the major considerations in the treatment of elderly patients is cost-effectiveness individualized to the patient's general health. Unlike the patients in clinical trials, more than 50% of older adults have three or more chronic diseases [29]. Thus, evidence-based clinical guidelines, which mainly focus on the management of a single disease, cannot be easily applied to adults with multimorbidity.

Since currently complications of HCV mostly affect members of the elderly population, they are in urgent need of effective HCV treatment. The approach we suggest for the treatment of patients over 70 with chronic HCV is illustrated in Fig 3. For those patients who have no major co-morbidities, more than moderate fibrosis, and a life expectancy greater than one year, there is a possibility of offering treatment. This needs to be presented to the patient and discussed before a final decision.




Our report provides evidence supporting the consideration of HCV treatment in clinical practice for older patients with significant fibrosis, especially as shorter regimens with higher SVR rates and less adverse effects are becoming the standard-of-care for HCV infection. At the same time, medications that are already licensed, and those in development, need to be systematically tested for the aging populations. This will require an investment in the design, development and execution of specific clinical trials and in addition reporting of real world experience of the currently approved medication.

Supporting Information
S1 File. Tables.

Table A: Assumption used for the Markov's Model. Table B: Life Expectancy for treated vs. non-treated patients by age for F1 to F4 (1–4).

doi:10.1371/journal.pone.0157832.s001
(DOCX)

Author Contributions
Conceived and designed the experiments: YM ML. Analyzed the data: YM SDHM EM ML. Wrote the paper: YM SDHM EM ML.

References
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Citation: Maor Y, Malnick SDH, Melzer E, Leshno M (2016) Treatment of Chronic Hepatitis C in the Aged – Does It Impact Life Expectancy? A Decision Analysis. PLoS ONE 11(7): e0157832. doi:10.1371/journal.pone.0157832
Editor: Vincent Wong, The Chinese University of Hong Kong, HONG KONG
Received: October 1, 2015; Accepted: June 4, 2016; Published: July 13, 2016
Copyright: © 2016 Maor et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the paper.
Funding: The authors have no support or funding to report.
Competing interests: The authors have declared that no competing interests exist.
Abbreviations: HCV, Hepatitis C virus; HCC, hepatocellular carcinoma; CDC, U.S. Centers for Disease Control and Prevention; USPSTF, U.S. Preventive Services Task Force; DAAs, direct-acting antivirals; SVR, sustained virological response; LY, life year; QALY, quality-adjusted life year; LE, life expectancy

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0157832#pone-0157832-g003


Tuesday, 12 July 2016

Generic Medications for Hepatitis C

Liver International
Liver International. 2016;36(7):925-928.

Generic Medications for Hepatitis C
While recent developments in direct-acting antiviral agents have proven a game-changer for treating hepatitis C, their high cost remains a barrier for many. Can--and should--generics take their place?
  • Abstract
  • Background
  • Generic Licensing and Production
  • Quality Controls
  • Importing Generic Medications for Personal use
  • Canada
  • EU Parallel Importing
  • Concerns and Persistent Questions

  • Excerpt:

    Importing Generic Medications for Personal use
    The continued medication access limitations have driven large interest in personal drug importation of the generic formulations. The United States Federal Food, Drug, and Cosmetic Act (Act) (21 U.S.C. § 331) prohibits the interstate shipment (including importation) of non-FDA-approved drugs. The FDA's concern is that some countries do not regulate or restrict the exportation of products, therefore patients who order medications from businesses located in such countries may not be afforded the protection and safety of either foreign or U.S. laws. Legislation in Congress has been proposed in the past to allow the re-importation of large quantities of brand-name prescription medications from Canada and other countries. However, these legislative proposals do not include provisions for sufficient resources for FDA inspections as well as testing to ensure that re-imported drugs meet the agency's standards for safety and effectiveness.


    The FDA focuses its enforcement resources on medications shipped commercially (including small shipments solicited by mail-order promotions). The agency does not focus on medications personally carried or shipped by a personal non-commercial representative of a consignee (buyer) or shipped from a foreign medical facility where a person has undergone treatment. The Regulation Procedures Manual for FDA personnel[8] includes guidance entitled 'Coverage of Personal Importations' for when to refrain from taking action against illegal personal importation or 'enforcement discretion'. Such circumstances include: (i) the drug is to treat a serious condition for which effective treatment is not available in the US; (ii) no commercialization or promotion of the drug to US residents; (iii) drug is not considered to represent an unreasonable risk; (iv) the individual importing the drug verifies in writing that it is for his or her own use, and provides contact information for the doctor providing treatment or shows the drug is for the continuation of treatment begun in a foreign country; and (v) generally, not more than a 3-month supply of the drug is imported.

    Personal drug importation is still illegal and the requirements and documentation described in the guidance does not represent a binding obligation by FDA personnel to allow personal importation. The goal of the guidance is to save FDA resources while allowing continuation of individual medical treatments initiated in a foreign country or allowing medical treatment sought by an individual that isn't available in the US. The guidance includes a warning that lower cost versions of medications available in the US are not covered under the guidance because the agency cannot verify the supply chain for the drugs imported and thus is as unreasonable risk.

    Full-text on Medscape