Antiviral Treatments

**47**

**Chapter 4**

**Abstract**

antivirals, antiviral therapy

**1. Introduction**

Host-Targeting Antivirals for

Treatment of chronic hepatitis C virus (HCV) infection has been revolutionized

during last years with the development of highly potent direct-acting antivirals (DAAs) specifically targeting HCV proteins. DAAs are the current standard of care for patients with chronic hepatitis C, leading to high cure rates. However, some hurdles exist including the high cost of these therapies restricting access to patients, their inability to protect against the risk of developing hepatocellular carcinoma in patients with advanced fibrosis, and emergence of resistant variants resulting in treatment failure. New therapeutic options should be essential to overcome DAAs limitations and improve survival. By targeting host-cell factors involved in HCV life cycle, host-targeting antivirals (HTAs) offer opportunity for promising anti-HCV therapy with low mutational rate and may act in a synergistic manner with DAAs to prevent viral resistance and reduce viral replication. Moreover, HTAs could be effective in difficult-to-cure patients by acting through complementary mechanisms. In this chapter, we will focus on the latest and most relevant studies regarding the hostcell factors required in HCV infection and explored as targets of antiviral therapy, we will also discuss the HTAs evaluated in preclinical and clinical development and

their potential role as alternative or complementary therapeutic strategies.

**Keywords:** chronic hepatitis C, direct-acting antivirals, cell factors, host-targeting

Hepatitis C virus (HCV) is a major causative agent of chronic liver diseases. Globally, it is estimated that 71 million people have chronic HCV infection, defined as the persistence of HCV genome in the blood for at least six months after the onset of acute infection [1, 2]. Patients with chronic HCV infection are at high risk of developing liver cirrhosis, hepatic decompensation, and hepatocellular carcinoma (HCC), which are the most common indications for liver transplantation [3]. Until 2011, the standard-of-care therapy for HCV infection consisted on pegylatedinterferon alpha in combination with the nucleotide analogue ribavirin (peg-IFNα/ RBV) leading to sustained virologic response (SVR) in 54–63% of patients with substantial side effects [4, 5]. The great advances in HCV research allowed the development of direct-acting antivirals (DAAs) which have dramatically improved the standard-of-care for HCV-infected patients [6, 7]. As their name suggests, DAAs are class of antivirals that directly target viral proteins required in HCV replication.

Treatment of Hepatitis C

*Bouchra Kitab, Michinori Kohara* 

*and Kyoko Tsukiyama-Kohara*

#### **Chapter 4**

## Host-Targeting Antivirals for Treatment of Hepatitis C

*Bouchra Kitab, Michinori Kohara and Kyoko Tsukiyama-Kohara*

#### **Abstract**

Treatment of chronic hepatitis C virus (HCV) infection has been revolutionized during last years with the development of highly potent direct-acting antivirals (DAAs) specifically targeting HCV proteins. DAAs are the current standard of care for patients with chronic hepatitis C, leading to high cure rates. However, some hurdles exist including the high cost of these therapies restricting access to patients, their inability to protect against the risk of developing hepatocellular carcinoma in patients with advanced fibrosis, and emergence of resistant variants resulting in treatment failure. New therapeutic options should be essential to overcome DAAs limitations and improve survival. By targeting host-cell factors involved in HCV life cycle, host-targeting antivirals (HTAs) offer opportunity for promising anti-HCV therapy with low mutational rate and may act in a synergistic manner with DAAs to prevent viral resistance and reduce viral replication. Moreover, HTAs could be effective in difficult-to-cure patients by acting through complementary mechanisms. In this chapter, we will focus on the latest and most relevant studies regarding the hostcell factors required in HCV infection and explored as targets of antiviral therapy, we will also discuss the HTAs evaluated in preclinical and clinical development and their potential role as alternative or complementary therapeutic strategies.

**Keywords:** chronic hepatitis C, direct-acting antivirals, cell factors, host-targeting antivirals, antiviral therapy

#### **1. Introduction**

Hepatitis C virus (HCV) is a major causative agent of chronic liver diseases. Globally, it is estimated that 71 million people have chronic HCV infection, defined as the persistence of HCV genome in the blood for at least six months after the onset of acute infection [1, 2]. Patients with chronic HCV infection are at high risk of developing liver cirrhosis, hepatic decompensation, and hepatocellular carcinoma (HCC), which are the most common indications for liver transplantation [3]. Until 2011, the standard-of-care therapy for HCV infection consisted on pegylatedinterferon alpha in combination with the nucleotide analogue ribavirin (peg-IFNα/ RBV) leading to sustained virologic response (SVR) in 54–63% of patients with substantial side effects [4, 5]. The great advances in HCV research allowed the development of direct-acting antivirals (DAAs) which have dramatically improved the standard-of-care for HCV-infected patients [6, 7]. As their name suggests, DAAs are class of antivirals that directly target viral proteins required in HCV replication.

The first-generation DAAs used in combination with peg-IFNα/RBV improve SVR rates by approximately 70% [8, 9]. Subsequently, IFN-free DAAs regimens, based on the use of highly potent and well-tolerated DAAs combinations were introduced and currently used for treatment, providing SVR in more than 95% of patients, with minimal side effects [10, 11].

Although DAAs offer the chance of viral cure for most of HCV patients, there are some limitations that restrain their full potential, including their high cost limiting access to treatment, the high mutation rate of HCV which may lead to the selection of DAA-resistant HCV variants resulting in treatment failure, and the low SVR rate in difficult-to-treat patients such as those with advanced liver cirrhosis [12–14]. Recent studies reported the inability of DAAs to protect against the risk of HCV re-infection of liver graft in transplanted patients, or the risk of developing HCC in patients with advanced liver fibrosis [15, 16]. Consequently, there is a need for other therapeutic options with better affordability, high rate of viral cure, and fewer cases of viral resistance. HCV requires host-cell factors to establish productive infection and propagation, thus development of host-targeting antivirals (HTAs) that interfere with these factors provides promising antiviral candidates, which may help to improve the current landscape of hepatitis C therapy [14, 17]. Several HTAs have been evaluated for preclinical and clinical development with some of them showing promising results. In this chapter, we provide an overview on recent advances in antiviral therapies against HCV and highlight the most important host factors explored as therapeutic targets. We also discuss the different HTAs evaluated in preclinical and clinical development and their potential impact as alternative or complementary therapeutic options to cure HCV infection and associated liver diseases.

#### **2. Molecular virology of HCV**

HCV is an enveloped, positive-sense single-stranded RNA virus, classified in the *hepacivirus* genus of *Flaviviridae* family [18]. HCV genomic RNA (~9.6 kb in length) contains highly structured 5′- and 3′-untranslated regions (UTRs) flanking a single open reading frame [19, 20]. The 5'-UTR is highly conserved and contains an internal ribosome entry site (IRES) essential to initiate viral RNA translation [21]. The high error prone of HCV NS5B RNA-dependent RNA polymerase leads to frequent mutations across the viral genome, resulting in high intra-patient variability (1–5%) represented in the form of quasispecies, and high inter-patient variability manifested by the existence of 7 genotypes, and 67 confirmed subtypes [22, 23]. HCV genotypes differ from each other by 31–33% at nucleotide level, compared with 15–25% between subtypes within a given genotype [24]. A global survey showed that HCV genotypes 1 and 3 are the most prevalent worldwide accounting for 46% and 30% of global HCV cases, respectively. Genotypes 2, 4, 5, and 6 are responsible for the majority of remaining HCV cases: 9%, 8%, <1%, and 5.4%, respectively [25]. Genotype 7 has been identified in Canada in few patients originating from Central Africa [26]. HCV genotypes have distinct geographic distributions throughout the world, which reflect differences in mode of transmission and ethnic variability. While genotype 1a is predominant in USA, genotype 1b dominated in Europe and Japan, genotype 2 dominated in West Africa and parts of South America, genotype 3 in south Asia, genotype 4 in middle East and Central/North Africa, genotype 5 in South Africa, and genotype 6 in Southeast Asia [25].

HCV replication cycle initiates through viral attachment and entry into the hepatocyte by clathrin-mediated endocytosis [27, 28]. The acidic pH of the early endosomes is essential to trigger fusion leading to nucleocapsid uncoating and release of the viral RNA genome in the cytosol [29]. At the rough endoplasmic reticulum (ER), HCV genomic RNA is translated via an HCV-IRES mediated

**49**

**hepatitis C**

*Host-Targeting Antivirals for Treatment of Hepatitis C DOI: http://dx.doi.org/10.5772/intechopen.95373*

mechanism to produce a single polyprotein of ~3010 amino acids [30]. This polyprotein is cleaved by cellular and viral proteases into three structural proteins that build up the HCV particle (Core and envelope glycoproteins E1 and E2) and seven nonstructural (NS) proteins permitting viral RNA replication, and viral particle assembly (p7, NS2, NS3, NS4A, NS4B, NS5A, and NS5B) [31]. The viroporin p7 and the cysteine protease NS2 are involved in viral particle assembly. NS3, NS4A, NS4B, NS5A, NS5B and HCV genomic RNA template form the viral replicase complex for HCV RNA replication [31, 32]. As all positive-strand RNA viruses, HCV induces massive rearrangements of cytoplasmic membranes in the host cell to generate a replication-favorable compartment called "the membranous web" in the case of HCV [33]. The membranous web is mainly composed of double membrane vesicles (DMVs) derived from the ER and may serve to increase the local concentration of viral proteins and relevant host cell factors required for efficient viral RNA replication [33, 34]. Within the replicase complex, the plus-strand RNA genome is replicated into a minus-strand RNA intermediate, which then gives rise to multiple plus-stranded HCV RNA copies [35]. The importance of specific lipids in HCV RNA replication has been highlighted. Indeed, HCV infection induces synthesis of

specific sphingolipids that enhance NS5B-mediated RNA replication [36].

**3. Impact of current antiviral therapies in the clinical outcome of** 

There are three critical points in the natural history of HCV infection including development of chronic hepatitis C, development of liver cirrhosis, and development of cirrhosis-related complications including portal hypertension and hepatocellular carcinoma (HCC) [46]. Chronic hepatitis C is a slowly progressive disease. It is estimated that 20–30% of chronic HCV patients develop liver cirrhosis over a 20 years period [46]. A deep inter-individual variability exists in the progression of hepatitis C and response to antiviral treatment, mainly related to viral factors such as HCV genotype, viral load, or coinfection with hepatitis B virus (HBV) or human immunodeficiency virus (HIV), and host factors such as patient's genetic background including interleukin-28B (IL-28B) polymorphism, age, gender, and obesity [47, 48]. The ultimate aim of antiviral treatment is to cure chronic HCV infection, in order to prevent the progression to liver cirrhosis and severe hepatic events (decompensation and HCC), and thereby improve patient survival and prevent

The newly progeny plus-strand RNAs can either be used for translation, therefore production of new viral proteins, or synthesis of new minus-strand RNAs, or packaged into viral particles. It has been shown that HCV assembly initiates at the ER membrane in close proximity to lipid droplets where the viral RNA is packaged into capsids [37]. HCV proteins NS5A and core have been reported as key players in the translocation of viral structures from the replication complex to lipid droplets [38]. The nascent nucleocapsids bud into the ER thereby acquiring a ER-derived lipid bilayer envelope in which the viral glycoproteins E1 and E2 are anchored as heterodimers [39]. Interestingly, a peculiar feature of HCV is its association with host lipoproteins and apolipoproteins such as ApoE, ApoB, and ApoA1, leading to the formation of lipo-viroparticles (LVPs) [40, 41]. Incorporation of host lipoproteins into HCV virions plays an essential role in virus infectivity and immune escape [40]. Next, LVPs traffic through the Golgi secretory pathway for final egress [42]. Several key components of the endosomal transport system are necessary for the egress of HCV LVPs, including the endosomal-sorting complex required for transport (ESCRT) pathway and Rab proteins [43, 44]. Estimations showed that approximatively 1.3 x 1012 HCV virions are produced per day in each infected patient [45].

#### *Host-Targeting Antivirals for Treatment of Hepatitis C DOI: http://dx.doi.org/10.5772/intechopen.95373*

*Advances in Hepatology*

with minimal side effects [10, 11].

**2. Molecular virology of HCV**

options to cure HCV infection and associated liver diseases.

The first-generation DAAs used in combination with peg-IFNα/RBV improve SVR rates by approximately 70% [8, 9]. Subsequently, IFN-free DAAs regimens, based on the use of highly potent and well-tolerated DAAs combinations were introduced and currently used for treatment, providing SVR in more than 95% of patients,

Although DAAs offer the chance of viral cure for most of HCV patients, there are some limitations that restrain their full potential, including their high cost limiting access to treatment, the high mutation rate of HCV which may lead to the selection of DAA-resistant HCV variants resulting in treatment failure, and the low SVR rate in difficult-to-treat patients such as those with advanced liver cirrhosis [12–14]. Recent studies reported the inability of DAAs to protect against the risk of HCV re-infection of liver graft in transplanted patients, or the risk of developing HCC in patients with advanced liver fibrosis [15, 16]. Consequently, there is a need for other therapeutic options with better affordability, high rate of viral cure, and fewer cases of viral resistance. HCV requires host-cell factors to establish productive infection and propagation, thus development of host-targeting antivirals (HTAs) that interfere with these factors provides promising antiviral candidates, which may help to improve the current landscape of hepatitis C therapy [14, 17]. Several HTAs have been evaluated for preclinical and clinical development with some of them showing promising results. In this chapter, we provide an overview on recent advances in antiviral therapies against HCV and highlight the most important host factors explored as therapeutic targets. We also discuss the different HTAs evaluated in preclinical and clinical development and their potential impact as alternative or complementary therapeutic

HCV is an enveloped, positive-sense single-stranded RNA virus, classified in the *hepacivirus* genus of *Flaviviridae* family [18]. HCV genomic RNA (~9.6 kb in length) contains highly structured 5′- and 3′-untranslated regions (UTRs) flanking a single open reading frame [19, 20]. The 5'-UTR is highly conserved and contains an internal ribosome entry site (IRES) essential to initiate viral RNA translation [21]. The high error prone of HCV NS5B RNA-dependent RNA polymerase leads to frequent mutations across the viral genome, resulting in high intra-patient variability (1–5%) represented in the form of quasispecies, and high inter-patient variability manifested by the existence of 7 genotypes, and 67 confirmed subtypes [22, 23]. HCV genotypes differ from each other by 31–33% at nucleotide level, compared with 15–25% between subtypes within a given genotype [24]. A global survey showed that HCV genotypes 1 and 3 are the most prevalent worldwide accounting for 46% and 30% of global HCV cases, respectively. Genotypes 2, 4, 5, and 6 are responsible for the majority of remaining HCV cases: 9%, 8%, <1%, and 5.4%, respectively [25]. Genotype 7 has been identified in Canada in few patients originating from Central Africa [26]. HCV genotypes have distinct geographic distributions throughout the world, which reflect differences in mode of transmission and ethnic variability. While genotype 1a is predominant in USA, genotype 1b dominated in Europe and Japan, genotype 2 dominated in West Africa and parts of South America, genotype 3 in south Asia, genotype 4 in middle East and Central/North

Africa, genotype 5 in South Africa, and genotype 6 in Southeast Asia [25].

HCV replication cycle initiates through viral attachment and entry into the hepatocyte by clathrin-mediated endocytosis [27, 28]. The acidic pH of the early endosomes is essential to trigger fusion leading to nucleocapsid uncoating and release of the viral RNA genome in the cytosol [29]. At the rough endoplasmic reticulum (ER), HCV genomic RNA is translated via an HCV-IRES mediated

**48**

mechanism to produce a single polyprotein of ~3010 amino acids [30]. This polyprotein is cleaved by cellular and viral proteases into three structural proteins that build up the HCV particle (Core and envelope glycoproteins E1 and E2) and seven nonstructural (NS) proteins permitting viral RNA replication, and viral particle assembly (p7, NS2, NS3, NS4A, NS4B, NS5A, and NS5B) [31]. The viroporin p7 and the cysteine protease NS2 are involved in viral particle assembly. NS3, NS4A, NS4B, NS5A, NS5B and HCV genomic RNA template form the viral replicase complex for HCV RNA replication [31, 32]. As all positive-strand RNA viruses, HCV induces massive rearrangements of cytoplasmic membranes in the host cell to generate a replication-favorable compartment called "the membranous web" in the case of HCV [33]. The membranous web is mainly composed of double membrane vesicles (DMVs) derived from the ER and may serve to increase the local concentration of viral proteins and relevant host cell factors required for efficient viral RNA replication [33, 34]. Within the replicase complex, the plus-strand RNA genome is replicated into a minus-strand RNA intermediate, which then gives rise to multiple plus-stranded HCV RNA copies [35]. The importance of specific lipids in HCV RNA replication has been highlighted. Indeed, HCV infection induces synthesis of specific sphingolipids that enhance NS5B-mediated RNA replication [36].

The newly progeny plus-strand RNAs can either be used for translation, therefore production of new viral proteins, or synthesis of new minus-strand RNAs, or packaged into viral particles. It has been shown that HCV assembly initiates at the ER membrane in close proximity to lipid droplets where the viral RNA is packaged into capsids [37]. HCV proteins NS5A and core have been reported as key players in the translocation of viral structures from the replication complex to lipid droplets [38]. The nascent nucleocapsids bud into the ER thereby acquiring a ER-derived lipid bilayer envelope in which the viral glycoproteins E1 and E2 are anchored as heterodimers [39]. Interestingly, a peculiar feature of HCV is its association with host lipoproteins and apolipoproteins such as ApoE, ApoB, and ApoA1, leading to the formation of lipo-viroparticles (LVPs) [40, 41]. Incorporation of host lipoproteins into HCV virions plays an essential role in virus infectivity and immune escape [40]. Next, LVPs traffic through the Golgi secretory pathway for final egress [42]. Several key components of the endosomal transport system are necessary for the egress of HCV LVPs, including the endosomal-sorting complex required for transport (ESCRT) pathway and Rab proteins [43, 44]. Estimations showed that approximatively 1.3 x 1012 HCV virions are produced per day in each infected patient [45].

#### **3. Impact of current antiviral therapies in the clinical outcome of hepatitis C**

There are three critical points in the natural history of HCV infection including development of chronic hepatitis C, development of liver cirrhosis, and development of cirrhosis-related complications including portal hypertension and hepatocellular carcinoma (HCC) [46]. Chronic hepatitis C is a slowly progressive disease. It is estimated that 20–30% of chronic HCV patients develop liver cirrhosis over a 20 years period [46]. A deep inter-individual variability exists in the progression of hepatitis C and response to antiviral treatment, mainly related to viral factors such as HCV genotype, viral load, or coinfection with hepatitis B virus (HBV) or human immunodeficiency virus (HIV), and host factors such as patient's genetic background including interleukin-28B (IL-28B) polymorphism, age, gender, and obesity [47, 48].

The ultimate aim of antiviral treatment is to cure chronic HCV infection, in order to prevent the progression to liver cirrhosis and severe hepatic events (decompensation and HCC), and thereby improve patient survival and prevent HCV transmission. Viral cure, known as sustained virological response (SVR) is defined as undetectable HCV RNA in blood 12–24 weeks after completing antiviral treatment [49, 50]. Current anti-HCV treatment consists on all-oral, IFN-free regimens combining highly potent, and well tolerated DAAs achieving SVR rates over 95% [11, 50]. DAAs specifically target HCV nonstructural proteins resulting in disruption of HCV replication (**Figure 1**). According to the therapeutic target and mechanism of action, DAAs are divided into four categories: NS3/4A protease inhibitors (e.g. simeprevir, paritaprevir, glecaprevir), NS5A protein inhibitors (e.g. velpatasvir, daclatasvir, pibrentasvir), NS5B nucleoside polymerase inhibitors and NS5B non-nucleoside polymerase inhibitors (e.g. sofosbuvir and dasabuvir, respectively) [11, 49, 50] (**Figure 1**). Combination of DAAs targeting different viral proteins regularly each of them with high potency and high genetic barrier, allows a high success of treatment regimens. Also, combination regimens comprising two drugs are preferred to triple combination regimens, to minimize the risk of side-effects and drug–drug interactions [11, 49, 50].

The introduction of DAAs has many positive impacts, through decreasing the incidence of severe hepatic complications and extra-hepatic diseases and reducing hepatitis C-related mortality [51, 52]. However, the high cost of DAAs still a barrier to access to therapy [12, 53]. According to recent estimations, the overall access to DAA is less than 10% of the HCV-infected patients on a global level [54]. Moreover, the potency of DAAs can be impaired by the emergence of specific amino acid substitutions designated resistance-associated substitutions (RASs). As an RNA virus, HCV easily develops a resistance to antiviral treatments due to its error-prone replication property and drug pressure. Risk of treatment failure is low in patients receiving 2 different categories of highly potent DAAs [13]. NS3/4A protease inhibitors are generally unaffected earlier by RASs, but many NS5A inhibitors continue to have overlapping resistance profiles. Furthermore, large studies have shown that a higher proportion of patients failed by an NS5A inhibitor-based regimen developed RASs than patients failed by NS3/4A protease inhibitor-based regimens [14, 55, 56]. The prevalence of RASs varied among HCV genotypes. HCV genotype 3 exhibits the

#### **Figure 1.**

*HCV genomic RNA and encoded viral proteins; virological functions of targeted non-structural proteins for direct-acting antivirals (DAAs) therapy. UTR, untranslated region; IRES, internal ribosome entry site.*

**51**

*Host-Targeting Antivirals for Treatment of Hepatitis C DOI: http://dx.doi.org/10.5772/intechopen.95373*

esis, but also novel candidates for antiviral therapy.

targeted host-cell factors and current development phase.

**4.1 HTAs involved in HCV entry**

highest resistance to DAAs therapy, with lower SVR rates compared to other genotypes [57]. Moreover, the debate continues about DAAs treatment and development of HCC. Some studies have shown that DAAs treatment was not associated with an increase in the development of HCC [58, 59]. Other studies have shown conflicting results, indicating that DAAs therapy is associated with an increase in the recurrence of HCC in patients previously cured by liver transplantation [60]. Collectively, these findings indicate that surveillance for HCC should be continued especially for patients with advanced fibrosis and cirrhosis. Interestingly, the persisting risk for HCC development following SVR in patients treated with DAAs raises questions about the mechanisms that maintain HCC risk in these patients after viral cure.

**4. Role of host-targeting antivirals in therapy of HCV infection**

HCV exploits the host cell extensively to complete replication cycle and establish persistent infection. The unveiling of HCV-host cell interactions at both structural and functional levels has been investigated intensely, in relation with great progress in HCV cell culture systems and experimental animal models, and also advances in functional genomics screening, including genome-wide small interfering RNA (siRNA) screens and genome-scale CRISPR–Cas screens [61–63]. These tools paved the way for the identification of host-encoded factors involved in each step of HCV life cycle [63, 64]. Characterization of these factors, also known as host dependencies factors, provides not only critical insights into mechanisms of HCV pathogen-

To cure HCV infection, a therapeutic drug should combine a potent antiviral activity and a high genetic barrier to viral resistance. Unlike DAAs, which target viral proteins of high variability, most of host-targeting antivirals (HTAs) are expected to have a high genetic barrier to viral resistance since host factors are less prone to mutations [65]. In addition, HTAs are usually genotype-independent and thus exhibit a pan-genotypic antiviral activity. Nonetheless, a major concern in the usage of HTAs is their interference with physiological functions of targeted host factors, which may induce cellular toxicity and side effects mutations [65, 66]. In the following sections, we discuss recent advances in HTAs against HCV that have potential as new therapeutic options and are in preclinical/clinical development. We also discuss their potential to overcome the current challenges of anti-HCV treatment. **Table 1** summarizes the different HTAs evaluated against HCV with their

HCV entry is the first step of virus–host cell interactions required for spread and maintenance of infection. HCV enters the hepatocyte through a highly orchestrated process involving HCV envelope glycoproteins E1 and E2 and four main host-cell receptors: the scavenger receptor class B type I (SR-BI), the human cluster of differentiation 81 (CD81) and the tight-junction proteins Claudin-1 (CLDN-1) and Occludin (OCLN) [67–69]. A genome-scale CRISPR/Cas9 knockout screening in human cells demonstrated that cellular receptors CD81, CLDN1, and OCLN are particularly critical for HCV infection *in vitro*, and thus determine the tropism of HCV for human cells [63]. HTAs targeting HCV entry offer the advantage of blocking HCV life cycle before the beginning of viral genome translation and replication, which might block cell–cell transmission, virus spread, and thus persistent infection [70]. Interestingly, because viral entry plays an important role during HCV re-infection of the graft in end-stage patients undergoing liver transplantation,

*Host-Targeting Antivirals for Treatment of Hepatitis C DOI: http://dx.doi.org/10.5772/intechopen.95373*

*Advances in Hepatology*

HCV transmission. Viral cure, known as sustained virological response (SVR) is defined as undetectable HCV RNA in blood 12–24 weeks after completing antiviral treatment [49, 50]. Current anti-HCV treatment consists on all-oral, IFN-free regimens combining highly potent, and well tolerated DAAs achieving SVR rates over 95% [11, 50]. DAAs specifically target HCV nonstructural proteins resulting in disruption of HCV replication (**Figure 1**). According to the therapeutic target and mechanism of action, DAAs are divided into four categories: NS3/4A protease inhibitors (e.g. simeprevir, paritaprevir, glecaprevir), NS5A protein inhibitors (e.g. velpatasvir, daclatasvir, pibrentasvir), NS5B nucleoside polymerase inhibitors and NS5B non-nucleoside polymerase inhibitors (e.g. sofosbuvir and dasabuvir, respectively) [11, 49, 50] (**Figure 1**). Combination of DAAs targeting different viral proteins regularly each of them with high potency and high genetic barrier, allows a high success of treatment regimens. Also, combination regimens comprising two drugs are preferred to triple combination regimens, to minimize the risk of

The introduction of DAAs has many positive impacts, through decreasing the incidence of severe hepatic complications and extra-hepatic diseases and reducing hepatitis C-related mortality [51, 52]. However, the high cost of DAAs still a barrier to access to therapy [12, 53]. According to recent estimations, the overall access to DAA is less than 10% of the HCV-infected patients on a global level [54]. Moreover, the potency of DAAs can be impaired by the emergence of specific amino acid substitutions designated resistance-associated substitutions (RASs). As an RNA virus, HCV easily develops a resistance to antiviral treatments due to its error-prone replication property and drug pressure. Risk of treatment failure is low in patients receiving 2 different categories of highly potent DAAs [13]. NS3/4A protease inhibitors are generally unaffected earlier by RASs, but many NS5A inhibitors continue to have overlapping resistance profiles. Furthermore, large studies have shown that a higher proportion of patients failed by an NS5A inhibitor-based regimen developed RASs than patients failed by NS3/4A protease inhibitor-based regimens [14, 55, 56]. The prevalence of RASs varied among HCV genotypes. HCV genotype 3 exhibits the

*HCV genomic RNA and encoded viral proteins; virological functions of targeted non-structural proteins for direct-acting antivirals (DAAs) therapy. UTR, untranslated region; IRES, internal ribosome entry site.*

side-effects and drug–drug interactions [11, 49, 50].

**50**

**Figure 1.**

highest resistance to DAAs therapy, with lower SVR rates compared to other genotypes [57]. Moreover, the debate continues about DAAs treatment and development of HCC. Some studies have shown that DAAs treatment was not associated with an increase in the development of HCC [58, 59]. Other studies have shown conflicting results, indicating that DAAs therapy is associated with an increase in the recurrence of HCC in patients previously cured by liver transplantation [60]. Collectively, these findings indicate that surveillance for HCC should be continued especially for patients with advanced fibrosis and cirrhosis. Interestingly, the persisting risk for HCC development following SVR in patients treated with DAAs raises questions about the mechanisms that maintain HCC risk in these patients after viral cure.

#### **4. Role of host-targeting antivirals in therapy of HCV infection**

HCV exploits the host cell extensively to complete replication cycle and establish persistent infection. The unveiling of HCV-host cell interactions at both structural and functional levels has been investigated intensely, in relation with great progress in HCV cell culture systems and experimental animal models, and also advances in functional genomics screening, including genome-wide small interfering RNA (siRNA) screens and genome-scale CRISPR–Cas screens [61–63]. These tools paved the way for the identification of host-encoded factors involved in each step of HCV life cycle [63, 64]. Characterization of these factors, also known as host dependencies factors, provides not only critical insights into mechanisms of HCV pathogenesis, but also novel candidates for antiviral therapy.

To cure HCV infection, a therapeutic drug should combine a potent antiviral activity and a high genetic barrier to viral resistance. Unlike DAAs, which target viral proteins of high variability, most of host-targeting antivirals (HTAs) are expected to have a high genetic barrier to viral resistance since host factors are less prone to mutations [65]. In addition, HTAs are usually genotype-independent and thus exhibit a pan-genotypic antiviral activity. Nonetheless, a major concern in the usage of HTAs is their interference with physiological functions of targeted host factors, which may induce cellular toxicity and side effects mutations [65, 66]. In the following sections, we discuss recent advances in HTAs against HCV that have potential as new therapeutic options and are in preclinical/clinical development. We also discuss their potential to overcome the current challenges of anti-HCV treatment. **Table 1** summarizes the different HTAs evaluated against HCV with their targeted host-cell factors and current development phase.

#### **4.1 HTAs involved in HCV entry**

HCV entry is the first step of virus–host cell interactions required for spread and maintenance of infection. HCV enters the hepatocyte through a highly orchestrated process involving HCV envelope glycoproteins E1 and E2 and four main host-cell receptors: the scavenger receptor class B type I (SR-BI), the human cluster of differentiation 81 (CD81) and the tight-junction proteins Claudin-1 (CLDN-1) and Occludin (OCLN) [67–69]. A genome-scale CRISPR/Cas9 knockout screening in human cells demonstrated that cellular receptors CD81, CLDN1, and OCLN are particularly critical for HCV infection *in vitro*, and thus determine the tropism of HCV for human cells [63]. HTAs targeting HCV entry offer the advantage of blocking HCV life cycle before the beginning of viral genome translation and replication, which might block cell–cell transmission, virus spread, and thus persistent infection [70]. Interestingly, because viral entry plays an important role during HCV re-infection of the graft in end-stage patients undergoing liver transplantation,


#### **Table 1.**

*Host-targeting antivirals against HCV with their targeted host-cell factors and current phase of clinical development.*

entry inhibitors represent an interesting strategy to prevent graft reinfection [71]. Numerous compounds have been evaluated, the most advanced was ITX-5061, an antagonist of SR-BI that reduces SR-BI-mediated HDL lipid transfer [72]. SR-BI binds HDL and delivers lipids into the cell membrane. The lipid transfer activities of SR-BI play an important role in HCV entry, thus reducing cholesterol transfer into the cell membrane may be one possible mechanism by which ITX-5061 reduces HCV entry [72]. An *in vitro* study indicated that ITX-5061 functions synergistically with the protease inhibitor telaprevir, and no cross-resistance is expected between ITX-5061 and HCV polymerase or protease inhibitors [73]. ITX-5061 completed a clinical

**53**

*Host-Targeting Antivirals for Treatment of Hepatitis C DOI: http://dx.doi.org/10.5772/intechopen.95373*

viral loads in patients undergoing liver transplantation [83].

Targeting HCV RNA replication is a promising approach to eradicate HCV from infected liver cells in patients. The most advanced HTAs against HCV RNA replication are the inhibitors of Cyclophilin A (CypA) and antagomirs of microRNA-122 (miR-122). Cyclophilin A (CypA) is an essential proviral factor for HCV replication, and interacts with HCV NS5A protein to initiate the formation of the replicase complex, and thereby promote viral RNA replication [84, 85]. Specific inhibition of CypA by cyclosporine A destroys the CypA/NS5A complex and suppresses HCV RNA replication *in vitro* [86]. Because cyclosporine A exhibits both antiviral and immunosuppressive activities, non-immunosuppressive antiviral derivatives of cyclosporine A were developed, including Alisporivir/Debio-025, N-methyl-4-isoleucine-cyclosporin (NIM811), and SCY-635 [87–89]. The comparison of CsA-resistant mutants for resistance to Alisporivir and NIM811 demonstrated that Alisporivir has the highest resistant activity against the adaptive mutations [90]. The antiviral effect of Alisporivir on HCV genotypes 1a or 1b has been confirmed in chimeric mice with human hepatocytes [87]. Alisporivir is the most advanced in clinical development. In a phase II clinical trial, administration of Alisporivir in combination with pegIFN-α/RBV to treatment-naïve HCV genotype 1 patients, resulted in SVR rates of 69–76% compared to 55% in the group receiving only pegIFN-α/RBV [91]. Recently, Alisporivir was explored as an interferon-free combination regimen with DAAs in HCV genotype 2 and 3 infected patients, resulting into SVR rates of 80–85% [92]. However, the development of Debio-025 was halted following the report of seven cases of acute pancreatitis [93]. For CypA inhibitor SCY-635, a clinical phase 2a study demonstrated that SCY-635 reduces HCV viral load and increases plasma levels of type I and III IFNs and IFN-stimulated genes, thereby contributes to

**4.2 HTAs involved in HCV RNA replication**

the activation of innate antiviral immunity [94].

phase 1b study. Oral ITX-5061 was safe and well tolerated over 28 days of dosing in noncirrhotic adults with chronic HCV infection [74]. This compound is undergoing phase II clinical trials in HCV-positive patients and appears to be a promising option for treatment [74]. Antibodies targeting CD81 have also been investigated and demonstrated potent antiviral effects in preclinical mouse studies [75]. In the case of CLDN1-targeting inhibitors, a rodent anti-CLDN1 mAb (OM-7D3-B3) demonstrated antiviral potential against HCV infection in primary human hepatocytes (PHHs) and human liver-chimeric mice [76, 77]. Towards a clinical development, Colpitts and colleagues [78] successfully humanized anti-CLDN1 mAb (OM-7D3-B3) into human IgG4 isotype, designed as H3L3. This antibody exhibits pan-genotypic activity against HCV entry without viral escape both *in vitro* and in mouse model [78]. Furthermore, H3L3 demonstrated a synergy with DAAs sofosbuvir and daclatasvir. Such synergy could allow shortening of treatment duration, thus reducing costs and side effects [79]. OCLN may also be considered as a potential target. To date, two successful human-rat chimeric mAbs have been developed against OCLN, and completely inhibit HCV infection *in vitro* and in human liver-chimeric mice without side effects [80]. Other inhibitors of kinases and host-cell pathways involved in HCV entry have been evaluated *in vitro* and significant results have been obtained in mouse models including Nieman-Pick C1-Like 1 (NPC1L1) and epidermal growth factor receptor (EGFR) [81, 82]. The clinically approved EGFR inhibitor Erlotinib, that prevents the formation of CLDN1-CD81 complex, and NPC1L1 inhibitor Ezetimibe, that decreases systemic cholesterol in patients, markedly impaired the establishment of HCV infection in the uPA-SCID mouse model [81, 82]. However, in a phase I clinical trial that enrolled, Ezetimibe elicits only minor effects on HCV

*Host-Targeting Antivirals for Treatment of Hepatitis C DOI: http://dx.doi.org/10.5772/intechopen.95373*

*Advances in Hepatology*

Scavenger receptor BI (SR-BI)

Claudin-1 (CLDN1)

Human cluster of differentiation 81 (CD81)

Epidermal growth factor receptor (EGFR)

Nieman-Pick C1-Like 1 (NPC1L1)

Diglyceride acyltransferase I (DGAT-I)

Acyl coenzyme A:cholesterol acyltransferase (ACAT)

Adaptorassociated kinase 1

(AAK1)

**Table 1.**

*development.*

Cyclin-associated kinase (GAK)

**Host factor Host-targeting** 

Occludin (OCLN) Anti-OCLN mAbs

micoRNA-122 -Miravirsen/

SPC3649


**antiviral**

Anti-CLDN1 mAbs (OM-7D3-B3, H3L3)

(Xi 1-3, Xi 37-5)

Cyclophilin A - Alisporivir RNA replication Phase 3

**HCV life cycle step Phase of** 

ITX-5061 Entry Phase 2 [73, 74]

Anti-CD81 mAbs Entry Preclinical [75]

Erlotinib Entry Preclinical [82]

Ezetimibe Entry Phase 1 [81, 83]



Avasimibe Assembly/Egress Preclinical [114, 115]

Sunitinib Assembly/Egress Preclinical [116]



**development**

Entry Preclinical [76–79]

(halted)

RNA replication Phase 2a [102–105]

Assembly/Egress Preclinical [118]

Entry Preclinical [80]

**References**

[87, 90–93]

**52**

entry inhibitors represent an interesting strategy to prevent graft reinfection [71]. Numerous compounds have been evaluated, the most advanced was ITX-5061, an antagonist of SR-BI that reduces SR-BI-mediated HDL lipid transfer [72]. SR-BI binds HDL and delivers lipids into the cell membrane. The lipid transfer activities of SR-BI play an important role in HCV entry, thus reducing cholesterol transfer into the cell membrane may be one possible mechanism by which ITX-5061 reduces HCV entry [72]. An *in vitro* study indicated that ITX-5061 functions synergistically with the protease inhibitor telaprevir, and no cross-resistance is expected between ITX-5061 and HCV polymerase or protease inhibitors [73]. ITX-5061 completed a clinical

*Host-targeting antivirals against HCV with their targeted host-cell factors and current phase of clinical* 

phase 1b study. Oral ITX-5061 was safe and well tolerated over 28 days of dosing in noncirrhotic adults with chronic HCV infection [74]. This compound is undergoing phase II clinical trials in HCV-positive patients and appears to be a promising option for treatment [74]. Antibodies targeting CD81 have also been investigated and demonstrated potent antiviral effects in preclinical mouse studies [75]. In the case of CLDN1-targeting inhibitors, a rodent anti-CLDN1 mAb (OM-7D3-B3) demonstrated antiviral potential against HCV infection in primary human hepatocytes (PHHs) and human liver-chimeric mice [76, 77]. Towards a clinical development, Colpitts and colleagues [78] successfully humanized anti-CLDN1 mAb (OM-7D3-B3) into human IgG4 isotype, designed as H3L3. This antibody exhibits pan-genotypic activity against HCV entry without viral escape both *in vitro* and in mouse model [78]. Furthermore, H3L3 demonstrated a synergy with DAAs sofosbuvir and daclatasvir. Such synergy could allow shortening of treatment duration, thus reducing costs and side effects [79]. OCLN may also be considered as a potential target. To date, two successful human-rat chimeric mAbs have been developed against OCLN, and completely inhibit HCV infection *in vitro* and in human liver-chimeric mice without side effects [80]. Other inhibitors of kinases and host-cell pathways involved in HCV entry have been evaluated *in vitro* and significant results have been obtained in mouse models including Nieman-Pick C1-Like 1 (NPC1L1) and epidermal growth factor receptor (EGFR) [81, 82]. The clinically approved EGFR inhibitor Erlotinib, that prevents the formation of CLDN1-CD81 complex, and NPC1L1 inhibitor Ezetimibe, that decreases systemic cholesterol in patients, markedly impaired the establishment of HCV infection in the uPA-SCID mouse model [81, 82]. However, in a phase I clinical trial that enrolled, Ezetimibe elicits only minor effects on HCV viral loads in patients undergoing liver transplantation [83].

#### **4.2 HTAs involved in HCV RNA replication**

Targeting HCV RNA replication is a promising approach to eradicate HCV from infected liver cells in patients. The most advanced HTAs against HCV RNA replication are the inhibitors of Cyclophilin A (CypA) and antagomirs of microRNA-122 (miR-122). Cyclophilin A (CypA) is an essential proviral factor for HCV replication, and interacts with HCV NS5A protein to initiate the formation of the replicase complex, and thereby promote viral RNA replication [84, 85]. Specific inhibition of CypA by cyclosporine A destroys the CypA/NS5A complex and suppresses HCV RNA replication *in vitro* [86]. Because cyclosporine A exhibits both antiviral and immunosuppressive activities, non-immunosuppressive antiviral derivatives of cyclosporine A were developed, including Alisporivir/Debio-025, N-methyl-4-isoleucine-cyclosporin (NIM811), and SCY-635 [87–89]. The comparison of CsA-resistant mutants for resistance to Alisporivir and NIM811 demonstrated that Alisporivir has the highest resistant activity against the adaptive mutations [90]. The antiviral effect of Alisporivir on HCV genotypes 1a or 1b has been confirmed in chimeric mice with human hepatocytes [87]. Alisporivir is the most advanced in clinical development. In a phase II clinical trial, administration of Alisporivir in combination with pegIFN-α/RBV to treatment-naïve HCV genotype 1 patients, resulted in SVR rates of 69–76% compared to 55% in the group receiving only pegIFN-α/RBV [91]. Recently, Alisporivir was explored as an interferon-free combination regimen with DAAs in HCV genotype 2 and 3 infected patients, resulting into SVR rates of 80–85% [92]. However, the development of Debio-025 was halted following the report of seven cases of acute pancreatitis [93]. For CypA inhibitor SCY-635, a clinical phase 2a study demonstrated that SCY-635 reduces HCV viral load and increases plasma levels of type I and III IFNs and IFN-stimulated genes, thereby contributes to the activation of innate antiviral immunity [94].

Another important host factor is the liver-specific microRNA-122 (miR-122). microRNAs are small (~22 nucleotides) endogenous noncoding RNAs, which bind to the 3′-untranslated region of the messenger RNAs (mRNAs), resulting in gene silencing through mRNA degradation or translational repression [95]. The replication of HCV in hepatocytes has been shown to be critically dependent on miR-122, as the sequestration of miR-122 in liver cells results in marked loss of replicating HCV RNAs [96]. Several mechanisms by which miR-122 promotes HCV replication have been reported. miR-122 promotes HCV genome replication by direct binding with two adjacent sites in the 5'-UTR of the HCV RNA [97]. miR-122 protects HCV RNA genome from degradation by host 5′-3′ exonucleases Xrn1 and Xrn2, and phosphatases DOM3Z and DUSP11 [98–101]. Therapeutic approaches based on inhibition of miR-122 using modified anti-sense oligonucleotides have been generated. Miravirsen/SPC3649 is a locked nucleic acid-modified DNA antisense oligonucleotide that sequesters mature miR-122 in a highly stable heteroduplex, thereby inhibiting its function. Miravirsen demonstrated antiviral activity against all HCV genotypes *in vitro* [102]. In a phase 2a study, the safety and efficacy of miravirsen were evaluated in 36 patients with chronic HCV genotype 1 infection. The results showed a prolonged and dose-dependent decrease in HCV RNA levels without evidence of viral resistance and serious adverse effects [103]. Miravirsen treatment results in a prolonged reduction in cholesterol levels in line with the effects of miR-122 on cholesterol metabolism [103, 104]. In addition, Miravirsen demonstrated a potent antiviral activity when tested against DAAresistant HCV variants [105]. Another antimir-122 molecule is RG-101, a hepatocyte targeted N-acetylgalactosamine conjugated oligonucleotide that antagonizes miR-122 [106]. Van der Ree and colleagues [106] performed a phase 1B study that assessed the safety, tolerability and antiviral effect of RG-101 in 32 patients chronically infected with HCV genotypes 1, 3, or 4. The results showed that RG-101 was well tolerated and resulted in substantial decrease in viral load in all treated patients within 4 weeks, and sustained virological response in 3 patients at week 76 of follow-up. However, viral rebound between weeks 5 and weeks 12 was observed in six patients with HCV genotype 1 [106]. Another phase 1B study assessed the effects of dosing RG-101 on antiviral immunity in chronic HCV patients and showed that a single dose of RG-101 led to a decrease in HCV RNA levels in all patients and SVR >76 weeks in 3 patients [107]. The combination of a highly potent DAAs with miravirsen or RG-101 could potentially shorten HCV treatment duration. Recently, two clinical studies were performed to evaluate the potential of combining a NS5B inhibitor (GSK2878175) and RG-101 as a single- visit curative regimen for chronic hepatitis C [108]. GSK2878175 molecule demonstrated acceptable safety, tolerability and pan-genotypic antiviral activity, especially for HCV genotype 3 that is considered difficult to treat. The results showed that daily oral administration of GSK2878175 with a single dose of RG- 101 results in high cure rates if the treatment duration is >9 weeks in noncirrhotic, treatment-naïve patients with HCV genotype 1 and 3 infections [108]. Altogether, these findings highlight the clinical potential of miR-122 inhibitors as complementary therapeutic strategy that especially may be valuable for difficult-to-cure patients with current DAAs.

#### **4.3 HTAs involved in HCV assembly and egress**

There is a close relationship between HCV particle biogenesis and host-cell lipid metabolism. HCV circulates as lipo-viralparticles (LVPs) in the blood of infected patients, thus targeting the host-cell factors involved in the lipid metabolism may provide potential therapeutic options. An essential cellular enzyme involved in this process is the diglyceride acyltransferase I (DGAT-I) which directly interacts with the HCV core protein, and is required for the trafficking of core to lipid droplets [109]. Inhibition of DGAT1 activity or RNAi-mediated knockdown of DGAT1

**55**

*Host-Targeting Antivirals for Treatment of Hepatitis C DOI: http://dx.doi.org/10.5772/intechopen.95373*

inhibitor could be used in combination with DAAs.

entry and assembly *in vitro* with limited off-target effects [118].

**5. Conclusion and prospects**

**Acknowledgements**

Technology of Japan.

**Conflict of interest**

The authors declare no conflict of interest.

severely impairs infectious viral particles production *in vitro*, implicating DGAT-1 as a new target for antiviral therapy [109]. Interestingly, quercetin, a natural flavonoid that inhibits DGAT-I, was reported to have anti-HCV properties [110]. In a phase I study, quercetin exhibited high safety and potent antiviral activity in patients with chronic HCV infection [111]. Moreover, the antiviral efficacy of the DGAT-I inhibitor LCQ908/pradigastat was assessed in phase II clinical trials in patients with HCV infection, but no significant decrease in HCV viral load was observed in treated patients [112]. Further studies are needed to determine whether the DGAT-I

Apolipoproteins (e.g. ApoE, ApoB, and ApoA1) are essential to the formation of

The great advances in hepatitis C treatment through the development of highly potent DAAs define the intense efforts towards a global eradication of HCV infection. However, most infected people live in low resource countries, which may limit access to treatment and restrain the impact of DAAs on the global burden of HCV infection and associated diseases. Another principal challenge is viral resistance, subsequent treatment failure and emergence of DAA-resistant variants. HTAs against host-cell factors required for HCV pathogenesis are promising candidates for development as alternative or complementary therapeutic options. Intense research on HTAs is needed to develop highly effective drugs with the least side effects. Several HTAs are at different stages of preclinical and clinical development, which promise for enlarged therapeutic arsenal against chronic HCV infection in the future.

This work was supported by grants from the Japan Agency for Medical Research and Development; the Tokyo Metropolitan Government; the Ministry of Health and Welfare of Japan; and the Ministry of Education, Culture, Sports, Science, and

infectious HCV particles during viral assembly, and highly infectious HCV particles are usually associated with more lipoproteins [40, 113]. Mechanistic studies demonstrated that Avasimibe, an inhibitor of acyl coenzyme A:cholesterol acyltransferase (ACAT), induced downregulation of microsomal triglyceride transfer protein expression, resulting in reduced ApoE and ApoB secretion [114]. Avasimibe significantly impairs the assembly of infectious HCV virions and exhibits significant pan-genotypic antiviral activity and great potential for combination therapy with DAAs [115]. Furthermore, the adaptor-associated kinase 1 (AAK1) and the cyclin-associated kinase (GAK) are known to regulate core-AP2M1 interaction [116]. Accordingly, Neveu and colleagues showed that AAK1 and GAK inhibitors, including the approved anti-cancer drugs sunitinib and erlotinib, can block HCV assembly [116, 117]. However, these compounds could induce adverse effects due to their lack of specificity. To overcome this limitation, a specific GAK inhibitor, isothiazolo [5,4-b]pyridine was developed [118]. This drug efficiently impairs HCV

*Host-Targeting Antivirals for Treatment of Hepatitis C DOI: http://dx.doi.org/10.5772/intechopen.95373*

*Advances in Hepatology*

Another important host factor is the liver-specific microRNA-122 (miR-122). microRNAs are small (~22 nucleotides) endogenous noncoding RNAs, which bind to the 3′-untranslated region of the messenger RNAs (mRNAs), resulting in gene silencing through mRNA degradation or translational repression [95]. The replication of HCV in hepatocytes has been shown to be critically dependent on miR-122, as the sequestration of miR-122 in liver cells results in marked loss of replicating HCV RNAs [96]. Several mechanisms by which miR-122 promotes HCV replication have been reported. miR-122 promotes HCV genome replication by direct binding with two adjacent sites in the 5'-UTR of the HCV RNA [97]. miR-122 protects HCV RNA genome from degradation by host 5′-3′ exonucleases Xrn1 and Xrn2, and phosphatases DOM3Z and DUSP11 [98–101]. Therapeutic approaches based on inhibition of miR-122 using modified anti-sense oligonucleotides have been generated. Miravirsen/SPC3649 is a locked nucleic acid-modified DNA antisense oligonucleotide that sequesters mature miR-122 in a highly stable heteroduplex, thereby inhibiting its function. Miravirsen demonstrated antiviral activity against all HCV genotypes *in vitro* [102]. In a phase 2a study, the safety and efficacy of miravirsen were evaluated in 36 patients with chronic HCV genotype 1 infection. The results showed a prolonged and dose-dependent decrease in HCV RNA levels without evidence of viral resistance and serious adverse effects [103]. Miravirsen treatment results in a prolonged reduction in cholesterol levels in line with the effects of miR-122 on cholesterol metabolism [103, 104]. In addition, Miravirsen demonstrated a potent antiviral activity when tested against DAAresistant HCV variants [105]. Another antimir-122 molecule is RG-101, a hepatocyte targeted N-acetylgalactosamine conjugated oligonucleotide that antagonizes miR-122 [106]. Van der Ree and colleagues [106] performed a phase 1B study that assessed the safety, tolerability and antiviral effect of RG-101 in 32 patients chronically infected with HCV genotypes 1, 3, or 4. The results showed that RG-101 was well tolerated and resulted in substantial decrease in viral load in all treated patients within 4 weeks, and sustained virological response in 3 patients at week 76 of follow-up. However, viral rebound between weeks 5 and weeks 12 was observed in six patients with HCV genotype 1 [106]. Another phase 1B study assessed the effects of dosing RG-101 on antiviral immunity in chronic HCV patients and showed that a single dose of RG-101 led to a decrease in HCV RNA levels in all patients and SVR >76 weeks in 3 patients [107]. The combination of a highly potent DAAs with miravirsen or RG-101 could potentially shorten HCV treatment duration. Recently, two clinical studies were performed to evaluate the potential of combining a NS5B inhibitor (GSK2878175) and RG-101 as a single- visit curative regimen for chronic hepatitis C [108]. GSK2878175 molecule demonstrated acceptable safety, tolerability and pan-genotypic antiviral activity, especially for HCV genotype 3 that is considered difficult to treat. The results showed that daily oral administration of GSK2878175 with a single dose of RG- 101 results in high cure rates if the treatment duration is >9 weeks in noncirrhotic, treatment-naïve patients with HCV genotype 1 and 3 infections [108]. Altogether, these findings highlight the clinical potential of miR-122 inhibitors as complementary therapeutic strategy that

especially may be valuable for difficult-to-cure patients with current DAAs.

There is a close relationship between HCV particle biogenesis and host-cell lipid metabolism. HCV circulates as lipo-viralparticles (LVPs) in the blood of infected patients, thus targeting the host-cell factors involved in the lipid metabolism may provide potential therapeutic options. An essential cellular enzyme involved in this process is the diglyceride acyltransferase I (DGAT-I) which directly interacts with the HCV core protein, and is required for the trafficking of core to lipid droplets [109]. Inhibition of DGAT1 activity or RNAi-mediated knockdown of DGAT1

**4.3 HTAs involved in HCV assembly and egress**

**54**

severely impairs infectious viral particles production *in vitro*, implicating DGAT-1 as a new target for antiviral therapy [109]. Interestingly, quercetin, a natural flavonoid that inhibits DGAT-I, was reported to have anti-HCV properties [110]. In a phase I study, quercetin exhibited high safety and potent antiviral activity in patients with chronic HCV infection [111]. Moreover, the antiviral efficacy of the DGAT-I inhibitor LCQ908/pradigastat was assessed in phase II clinical trials in patients with HCV infection, but no significant decrease in HCV viral load was observed in treated patients [112]. Further studies are needed to determine whether the DGAT-I inhibitor could be used in combination with DAAs.

Apolipoproteins (e.g. ApoE, ApoB, and ApoA1) are essential to the formation of infectious HCV particles during viral assembly, and highly infectious HCV particles are usually associated with more lipoproteins [40, 113]. Mechanistic studies demonstrated that Avasimibe, an inhibitor of acyl coenzyme A:cholesterol acyltransferase (ACAT), induced downregulation of microsomal triglyceride transfer protein expression, resulting in reduced ApoE and ApoB secretion [114]. Avasimibe significantly impairs the assembly of infectious HCV virions and exhibits significant pan-genotypic antiviral activity and great potential for combination therapy with DAAs [115]. Furthermore, the adaptor-associated kinase 1 (AAK1) and the cyclin-associated kinase (GAK) are known to regulate core-AP2M1 interaction [116]. Accordingly, Neveu and colleagues showed that AAK1 and GAK inhibitors, including the approved anti-cancer drugs sunitinib and erlotinib, can block HCV assembly [116, 117]. However, these compounds could induce adverse effects due to their lack of specificity. To overcome this limitation, a specific GAK inhibitor, isothiazolo [5,4-b]pyridine was developed [118]. This drug efficiently impairs HCV entry and assembly *in vitro* with limited off-target effects [118].

#### **5. Conclusion and prospects**

The great advances in hepatitis C treatment through the development of highly potent DAAs define the intense efforts towards a global eradication of HCV infection. However, most infected people live in low resource countries, which may limit access to treatment and restrain the impact of DAAs on the global burden of HCV infection and associated diseases. Another principal challenge is viral resistance, subsequent treatment failure and emergence of DAA-resistant variants. HTAs against host-cell factors required for HCV pathogenesis are promising candidates for development as alternative or complementary therapeutic options. Intense research on HTAs is needed to develop highly effective drugs with the least side effects. Several HTAs are at different stages of preclinical and clinical development, which promise for enlarged therapeutic arsenal against chronic HCV infection in the future.

#### **Acknowledgements**

This work was supported by grants from the Japan Agency for Medical Research and Development; the Tokyo Metropolitan Government; the Ministry of Health and Welfare of Japan; and the Ministry of Education, Culture, Sports, Science, and Technology of Japan.

#### **Conflict of interest**

The authors declare no conflict of interest.

*Advances in Hepatology*

#### **Author details**

Bouchra Kitab1 , Michinori Kohara2 and Kyoko Tsukiyama-Kohara1 \*

1 Transboundary Animal Diseases Centre, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan

2 The Tokyo Metropolitan Institute of Medical Science, Japan

\*Address all correspondence to: kkohara@vet.kagoshima-u.ac.jp

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**57**

*Host-Targeting Antivirals for Treatment of Hepatitis C DOI: http://dx.doi.org/10.5772/intechopen.95373*

> the protease inhibitors boceprevir and telaprevir for chronic hepatitis C virus. J Manag Care Pharm. 2011;17:685-694. doi: 10.18553/jmcp.2011.17.9.685

[9] Lawitz E, Lalezari JP, Hassanein T, Kowdley KV, Poordad FF, Sheikh AM, Afdhal NH, Bernstein DE, Dejesus E, Freilich B, Nelson DR, Dieterich DT, Jacobson IM, Jensen D, Abrams GA, Darling JM, Rodriguez-Torres M, Reddy KR, Sulkowski MS, Bzowej NH, Hyland RH, Mo H, Lin M, Mader M, Hindes R, Albanis E, Symonds WT, Berrey MM, Muir A. Sofosbuvir in combination with peginterferon alfa-2a and ribavirin for non-cirrhotic, treatment-naive patients with genotypes 1, 2, and 3 hepatitis C infection: a randomised, double-blind, phase 2 trial. Lancet Infect Dis. 2013;13:401-408. doi:

10.1016/S1473-3099(13)70033-1

Hiromitsu K, Kurosaki M, Koike K, Suzuki F, Takikawa H, Tanaka A, Tanaka E, Tanaka Y, Tsubouchi H, Hayashi N, Hiramatsu N, Yotsuyanagi H. JSH Guidelines for the Management of Hepatitis C Virus Infection: A 2016 update for genotype 1 and 2. Hepatol Res. 2016;46:129-165. doi: 10.1111/

[11] Pawlotsky JM. Interferon-Free Hepatitis C Virus Therapy. Cold Spring Harb Perspect Med. 2020;10:a036855. doi: 10.1101/cshperspect.a036855

[12] Dusheiko G, Gore C. Antiviral treatment for hepatitis C: rebalancing cost, affordability, and availability. Lancet Glob Health. 2019;7:e1150-e1151. doi: 10.1016/S2214-109X(19)30313-4

[13] Sarrazin C. The importance of resistance to direct antiviral drugs in HCV infection in clinical practice. J Hepatol. 2016;64:486-504. doi: 10.1016/j.

jhep.2015.09.011

[10] Asahina Y, Izumi N,

hepr.12645

[1] World Health Organization. Global Hepatitis Report 2017; World Health Organization: Geneva,

[2] Polaris Observatory HCV

2017;2:161-176. doi: 10.1016/ S2468-1253(16)30181-9

978. doi: 10.1002/cld.62

200403020-00010

10.1002/hep.26371

pharmthera.2017.10.009

nri3463

[4] Hadziyannis SJ, Sette H Jr, Morgan TR, Balan V, Diago M,

H Jr, Bernstein D, Rizzetto M, Zeuzem S, Pockros PJ, Lin A, Ackrill AM; PEGASYS International Study Group. Peginterferon-alpha2a and ribavirin combination therapy in chronic hepatitis C: a randomized study of treatment duration and ribavirin dose. Ann Intern Med. 2004;140:346- 355. doi: 10.7326/0003-4819-140-5-

[3] Brown RS. Hepatitis C and liver transplantation. Nature. 2005;436:973-

Marcellin P, Ramadori G, Bodenheimer

[5] Heim MH. 25 years of interferonbased treatment of chronic hepatitis C: an epoch coming to an end. Nat Rev Immunol. 2013;13:535-542. doi: 10.1038/

[6] Aghemo A, De Francesco R. New horizons in hepatitis C antiviral therapy with direct acting antivirals. Hepatology. 2013;58:428-438. doi:

[7] Spengler U. Direct antiviral agents (DAAs)—A new age in the treatment of hepatitis C virus infection. Pharmacol Ther. 2018;183:118-126. doi: 10.1016/j.

[8] Tungol, A., Rademacher, K., Schafer, J.A., 2011. Formulary management of

Collaborators. Global prevalence and genotype distribution of hepatitis C virus infection in 2015: a modelling study. Lancet Gastroenterol Hepatol.

**References**

Switzerland,2017.

*Host-Targeting Antivirals for Treatment of Hepatitis C DOI: http://dx.doi.org/10.5772/intechopen.95373*

#### **References**

*Advances in Hepatology*

**56**

**Author details**

Bouchra Kitab1

, Michinori Kohara2

2 The Tokyo Metropolitan Institute of Medical Science, Japan

\*Address all correspondence to: kkohara@vet.kagoshima-u.ac.jp

Kagoshima University, Kagoshima, Japan

provided the original work is properly cited.

and Kyoko Tsukiyama-Kohara1

1 Transboundary Animal Diseases Centre, Joint Faculty of Veterinary Medicine,

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*

[1] World Health Organization. Global Hepatitis Report 2017; World Health Organization: Geneva, Switzerland,2017.

[2] Polaris Observatory HCV Collaborators. Global prevalence and genotype distribution of hepatitis C virus infection in 2015: a modelling study. Lancet Gastroenterol Hepatol. 2017;2:161-176. doi: 10.1016/ S2468-1253(16)30181-9

[3] Brown RS. Hepatitis C and liver transplantation. Nature. 2005;436:973- 978. doi: 10.1002/cld.62

[4] Hadziyannis SJ, Sette H Jr, Morgan TR, Balan V, Diago M, Marcellin P, Ramadori G, Bodenheimer H Jr, Bernstein D, Rizzetto M, Zeuzem S, Pockros PJ, Lin A, Ackrill AM; PEGASYS International Study Group. Peginterferon-alpha2a and ribavirin combination therapy in chronic hepatitis C: a randomized study of treatment duration and ribavirin dose. Ann Intern Med. 2004;140:346- 355. doi: 10.7326/0003-4819-140-5- 200403020-00010

[5] Heim MH. 25 years of interferonbased treatment of chronic hepatitis C: an epoch coming to an end. Nat Rev Immunol. 2013;13:535-542. doi: 10.1038/ nri3463

[6] Aghemo A, De Francesco R. New horizons in hepatitis C antiviral therapy with direct acting antivirals. Hepatology. 2013;58:428-438. doi: 10.1002/hep.26371

[7] Spengler U. Direct antiviral agents (DAAs)—A new age in the treatment of hepatitis C virus infection. Pharmacol Ther. 2018;183:118-126. doi: 10.1016/j. pharmthera.2017.10.009

[8] Tungol, A., Rademacher, K., Schafer, J.A., 2011. Formulary management of

the protease inhibitors boceprevir and telaprevir for chronic hepatitis C virus. J Manag Care Pharm. 2011;17:685-694. doi: 10.18553/jmcp.2011.17.9.685

[9] Lawitz E, Lalezari JP, Hassanein T, Kowdley KV, Poordad FF, Sheikh AM, Afdhal NH, Bernstein DE, Dejesus E, Freilich B, Nelson DR, Dieterich DT, Jacobson IM, Jensen D, Abrams GA, Darling JM, Rodriguez-Torres M, Reddy KR, Sulkowski MS, Bzowej NH, Hyland RH, Mo H, Lin M, Mader M, Hindes R, Albanis E, Symonds WT, Berrey MM, Muir A. Sofosbuvir in combination with peginterferon alfa-2a and ribavirin for non-cirrhotic, treatment-naive patients with genotypes 1, 2, and 3 hepatitis C infection: a randomised, double-blind, phase 2 trial. Lancet Infect Dis. 2013;13:401-408. doi: 10.1016/S1473-3099(13)70033-1

[10] Asahina Y, Izumi N, Hiromitsu K, Kurosaki M, Koike K, Suzuki F, Takikawa H, Tanaka A, Tanaka E, Tanaka Y, Tsubouchi H, Hayashi N, Hiramatsu N, Yotsuyanagi H. JSH Guidelines for the Management of Hepatitis C Virus Infection: A 2016 update for genotype 1 and 2. Hepatol Res. 2016;46:129-165. doi: 10.1111/ hepr.12645

[11] Pawlotsky JM. Interferon-Free Hepatitis C Virus Therapy. Cold Spring Harb Perspect Med. 2020;10:a036855. doi: 10.1101/cshperspect.a036855

[12] Dusheiko G, Gore C. Antiviral treatment for hepatitis C: rebalancing cost, affordability, and availability. Lancet Glob Health. 2019;7:e1150-e1151. doi: 10.1016/S2214-109X(19)30313-4

[13] Sarrazin C. The importance of resistance to direct antiviral drugs in HCV infection in clinical practice. J Hepatol. 2016;64:486-504. doi: 10.1016/j. jhep.2015.09.011

[14] Hayes CN, Chayama K. Why highly effective drugs are not enough: the need for an affordable solution to eliminating HCV. Expert Rev Clin Pharmacol. 2017;10:583-594. doi: 10.1080/17512433.2017.1313111

[15] Torres HA, Vauthey JN, Economides MP, Mahale P, Kaseb A. Hepatocellular carcinoma recurrence after treatment with direct-acting antivirals: First, do no harm by withdrawing treatment. J Hepatol. 2016;65:862-864. doi:10.1016/j. jhep.2016.05.034

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Meer AJ, Patick AK, Chen A, Zhou Y, Persson R, King BD, Kauppinen S, Levin AA, Hodges MR. Treatment of HCV infection by targeting microRNA. *Host-Targeting Antivirals for Treatment of Hepatitis C DOI: http://dx.doi.org/10.5772/intechopen.95373*

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[103] Janssen HL, Reesink HW, Lawitz EJ, Zeuzem S, Rodriguez-Torres M, Patel K, van der Meer AJ, Patick AK, Chen A, Zhou Y, Persson R, King BD, Kauppinen S, Levin AA, Hodges MR. Treatment of HCV infection by targeting microRNA. N Engl J Med. 2013;368:1685-1694. doi: 10.1056/NEJMoa1209026

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[105] Liu F, Shimakami T, Murai K, Shirasaki T, Funaki M, Honda M, Murakami S, Yi M, Tang H, Kaneko S. Efficient Suppression of Hepatitis C Virus Replication by Combination Treatment with miR-122 Antagonism and Direct-acting Antivirals in Cell Culture Systems. Sci Rep. 2016;6:30939. doi: 10.1038/srep30939

[106] van der Ree MH, de Vree JM, Stelma F, Willemse S, van der Valk M, Rietdijk S, Molenkamp R, Schinkel J, van Nuenen AC, Beuers U, Hadi S, Harbers M, van der Veer E, Liu K, Grundy J, Patick AK, Pavlicek A, Blem J, Huang M, Grint P, Neben S, Gibson NW, Kootstra NA, Reesink HW. Safety, tolerability, and antiviral effect of RG-101 in patients with chronic hepatitis C: a phase 1B, double-blind, randomised controlled trial. Lancet. 2017;389:709-717. doi: 10.1016/ S0140-6736(16)31715-9

[107] Stelma F, van der Ree MH, Sinnige MJ, Brown A, Swadling L, de Vree JML, Willemse SB, van der Valk M, Grint P, Neben S, Klenerman P, Barnes E, Kootstra NA, Reesink HW. Immune phenotype and function of natural killer and T cells in chronic hepatitis C patients who received a single dose of anti-MicroRNA-122, RG-101. Hepatology. 2017;66:57-68. doi: 10.1002/hep.29148

[108] Deng Y, Campbell F, Han K, Theodore D, Deeg M, Huang M, Hamatake R, Lahiri S,

Chen S, Horvath G, Manolakopoulos S, Dalekos GN, Papatheodoridis G, Goulis I, Banyai T, Jilma B, Leivers M. Randomized clinical trials towards a single-visit cure for chronic hepatitis C: Oral GSK2878175 and injectable RG-101 in chronic hepatitis C patients and longacting injectable GSK2878175 in healthy participants. J Viral Hepat. 2020;27:699- 708. doi: 10.1111/jvh.13282

[109] Herker E, Harris C, Hernandez C, Carpentier A, Kaehlcke K, Rosenberg AR, Farese RV Jr, Ott M. Efficient hepatitis C virus particle formation requires diacylglycerol acyltransferase-1. Nat Med. 2010;16:1295-1298. doi: 10.1038/ nm.2238

[110] Rojas Á, Del Campo JA, Clement S, Lemasson M, García-Valdecasas M, Gil-Gómez A, Ranchal I, Bartosch B, Bautista JD, Rosenberg AR, Negro F, Romero-Gómez M. Effect of Quercetin on Hepatitis C Virus Life Cycle: From Viral to Host Targets. Sci Rep. 2016;6:31777. doi: 10.1038/srep31777

[111] Lu NT, Crespi CM, Liu NM, Vu JQ, Ahmadieh Y, Wu S, Lin S, McClune A, Durazo F, Saab S, Han S, Neiman DC, Beaven S, French SW. A Phase I Dose Escalation Study Demonstrates Quercetin Safety and Explores Potential for Bioflavonoid Antivirals in Patients with Chronic Hepatitis C. Phytother Res. 2016;30:160-168. doi: 10.1002/ ptr.5518

[112] Gane E, Stedman C, Dole K, Chen J, Meyers CD, Wiedmann B, Zhang J, Raman P, Colvin RA. A Diacylglycerol Transferase 1 Inhibitor Is a Potent Hepatitis C Antiviral in Vitro but Not in Patients in a Randomized Clinical Trial. ACS Infect Dis. 2017;3:144-151. doi: 10.1021/acsinfecdis.6b00138

[113] Falcón V, Acosta-Rivero N, González S, Dueñas-Carrera S, Martinez-Donato G, Menéndez I, Garateix R, Silva JA, Acosta E, Kourı J. Ultrastructural and biochemical basis for hepatitis C virus morphogenesis. Virus Genes. 2017;53:151-164. doi: 10.1007/s11262-017-1426-2

[114] Insull W Jr, Koren M, Davignon J, Sprecher D, Schrott H, Keilson LM, Brown AS, Dujovne CA, Davidson MH, McLain R, Heinonen T. Efficacy and short-term safety of a new ACAT inhibitor, avasimibe, on lipids, lipoproteins, and apolipoproteins, in patients with combined hyperlipidemia. Atherosclerosis. 2001;157:137-144. doi: 10.1016/s0021-9150(00)00615-8

[115] Hu L, Li J, Cai H, Yao W, Xiao J, Li YP, Qiu X, Xia H, Peng T. Avasimibe: A novel hepatitis C virus inhibitor that targets the assembly of infectious viral particles. Antiviral Res. 2017;148:5-14. doi: 10.1016/j.antiviral.2017.10.016

[116] Neveu G, Barouch-Bentov R, Ziv-Av A, Gerber D, Jacob Y, Einav S. Identification and targeting of an interaction between a tyrosine motif within hepatitis C virus core protein and AP2M1 essential for viral assembly. PLoS Pathog. 2012;8:e1002845. doi: 10.1371/journal.ppat.1002845

[117] Neveu G, Ziv-Av A, Barouch-Bentov R, Berkerman E, Mulholland J, Einav S. AP-2-associated protein kinase 1 and cyclin G-associated kinase regulate hepatitis C virus entry and are potential drug targets. J Virol. 2015;89:4387-404. doi: 10.1128/ JVI.02705-14

[118] Kovackova S, Chang L, Bekerman E, Neveu G, Barouch-Bentov R, Chaikuad A, Heroven C, Šála M, De Jonghe S, Knapp S, Einav S, Herdewijn P. Selective Inhibitors of Cyclin G Associated Kinase (GAK) as Anti-Hepatitis C Agents. J Med Chem. 2015 23;58:3393-3410. doi: 10.1021/ jm501759m

**67**

**Chapter 5**

**Abstract**

other studies published.

test, seroclearence

**1. Introduction**

(HCV) due to shared routes of transmission.

The Influence of Protease

and HCV Co-Infection

*Elena Dumea and Simona Claudia Cambrea*

Inhibitors on the Evolution of

Hepatitis C in Patients with HIV

Prevalence of hepatitis C in HIV infected patients is much higher than in the general population. There is the possibility of viral clearance HCV, in some patients co-infected HIV and HCV, in the phase of immune reconstruction after antiretroviral treatment (ART). There are patients' anti-HCV positive who initially did not show HCV viral load detected and after the start of ART becomes HCV viral load detectable. There are studies that described that immune restoration with increase in CD4+ and CD8+ T cells, from ART, was important in control of HCV viremia. Has been proposed hypothesis that direct or indirect effect of ART on HCV replication play a role in spontaneous resolution of HCV infection. We evaluated the co-infected patients with HIV and HCV under combined antiretroviral treatment, containing PI boosted with ritonavir in terms of immunological and virological status (for both infection) and also liver disease. Patients were evaluated for liver damage by non-invasive methods. We have shown that a small percentage of patients have severe liver damage. We demonstrated the negative role of HCV on immunological status and in liver fibrosis in co-infected patients. A high proportion of these HIV and HCV co-infected patients had no detectable viremia, higher than

**Keywords:** protease inhibitors, HCV, HIV, co-infection, non invasive liver fibrosis

Approximate 1/3 of HIV infected patients are also infected with hepatitis C virus

The clinical implications of this crossroad are important and challenging issues

Patients with HIV and HCV infection have higher risk for developing cirrhosis, hepatic decompensation, increased rates of end-stage liver diseases, hepatocellular

regarding the evaluation and management of the co-infected patient.

carcinoma and shortened lifespan after hepatic decompensation.

#### **Chapter 5**

*Advances in Hepatology*

708. doi: 10.1111/jvh.13282

[109] Herker E, Harris C, Hernandez C, Carpentier A, Kaehlcke K, Rosenberg AR, Farese RV Jr, Ott M. Efficient hepatitis C virus particle formation requires diacylglycerol acyltransferase-1. Nat Med. 2010;16:1295-1298. doi: 10.1038/

nm.2238

ptr.5518

Chen S, Horvath G, Manolakopoulos S, Dalekos GN, Papatheodoridis G, Goulis I, Banyai T, Jilma B, Leivers M. Randomized clinical trials towards a single-visit cure for chronic hepatitis C: Oral GSK2878175 and injectable RG-101 in chronic hepatitis C patients and longacting injectable GSK2878175 in healthy participants. J Viral Hepat. 2020;27:699Ultrastructural and biochemical basis for hepatitis C virus morphogenesis. Virus Genes. 2017;53:151-164. doi:

[114] Insull W Jr, Koren M, Davignon J, Sprecher D, Schrott H, Keilson LM, Brown AS, Dujovne CA, Davidson MH, McLain R, Heinonen T. Efficacy and short-term safety of a new ACAT inhibitor, avasimibe, on lipids, lipoproteins, and apolipoproteins, in patients with combined hyperlipidemia. Atherosclerosis. 2001;157:137-144. doi: 10.1016/s0021-9150(00)00615-8

[115] Hu L, Li J, Cai H, Yao W, Xiao J, Li YP, Qiu X, Xia H, Peng T. Avasimibe: A novel hepatitis C virus inhibitor that targets the assembly of infectious viral particles. Antiviral Res. 2017;148:5-14. doi: 10.1016/j.antiviral.2017.10.016

[116] Neveu G, Barouch-Bentov R, Ziv-Av A, Gerber D, Jacob Y,

[117] Neveu G, Ziv-Av A,

JVI.02705-14

jm501759m

Barouch-Bentov R, Berkerman E, Mulholland J, Einav S. AP-2-associated protein kinase 1 and cyclin G-associated

kinase regulate hepatitis C virus entry and are potential drug targets. J Virol. 2015;89:4387-404. doi: 10.1128/

[118] Kovackova S, Chang L, Bekerman E, Neveu G, Barouch-Bentov R, Chaikuad A, Heroven C, Šála M, De Jonghe S, Knapp S, Einav S, Herdewijn P. Selective Inhibitors of Cyclin G Associated Kinase (GAK) as Anti-Hepatitis C Agents. J Med Chem. 2015 23;58:3393-3410. doi: 10.1021/

Einav S. Identification and targeting of an interaction between a tyrosine motif within hepatitis C virus core protein and AP2M1 essential for viral assembly. PLoS Pathog. 2012;8:e1002845. doi: 10.1371/journal.ppat.1002845

10.1007/s11262-017-1426-2

[110] Rojas Á, Del Campo JA, Clement S, Lemasson M, García-Valdecasas M, Gil-Gómez A, Ranchal I, Bartosch B, Bautista JD, Rosenberg AR, Negro F, Romero-Gómez M. Effect of Quercetin

[111] Lu NT, Crespi CM, Liu NM, Vu JQ, Ahmadieh Y, Wu S, Lin S, McClune A, Durazo F, Saab S, Han S, Neiman DC, Beaven S, French SW. A Phase I Dose Escalation Study Demonstrates

Quercetin Safety and Explores Potential for Bioflavonoid Antivirals in Patients with Chronic Hepatitis C. Phytother Res. 2016;30:160-168. doi: 10.1002/

[112] Gane E, Stedman C, Dole K, Chen J, Meyers CD, Wiedmann B, Zhang J, Raman P, Colvin RA. A Diacylglycerol Transferase 1 Inhibitor Is a Potent Hepatitis C Antiviral in Vitro but Not in Patients in a Randomized Clinical Trial. ACS Infect Dis. 2017;3:144-151. doi:

10.1021/acsinfecdis.6b00138

[113] Falcón V, Acosta-Rivero N, González S, Dueñas-Carrera S, Martinez-Donato G, Menéndez I, Garateix R, Silva JA, Acosta E, Kourı J.

on Hepatitis C Virus Life Cycle: From Viral to Host Targets. Sci Rep. 2016;6:31777. doi: 10.1038/srep31777

**66**

## The Influence of Protease Inhibitors on the Evolution of Hepatitis C in Patients with HIV and HCV Co-Infection

*Elena Dumea and Simona Claudia Cambrea*

#### **Abstract**

Prevalence of hepatitis C in HIV infected patients is much higher than in the general population. There is the possibility of viral clearance HCV, in some patients co-infected HIV and HCV, in the phase of immune reconstruction after antiretroviral treatment (ART). There are patients' anti-HCV positive who initially did not show HCV viral load detected and after the start of ART becomes HCV viral load detectable. There are studies that described that immune restoration with increase in CD4+ and CD8+ T cells, from ART, was important in control of HCV viremia. Has been proposed hypothesis that direct or indirect effect of ART on HCV replication play a role in spontaneous resolution of HCV infection. We evaluated the co-infected patients with HIV and HCV under combined antiretroviral treatment, containing PI boosted with ritonavir in terms of immunological and virological status (for both infection) and also liver disease. Patients were evaluated for liver damage by non-invasive methods. We have shown that a small percentage of patients have severe liver damage. We demonstrated the negative role of HCV on immunological status and in liver fibrosis in co-infected patients. A high proportion of these HIV and HCV co-infected patients had no detectable viremia, higher than other studies published.

**Keywords:** protease inhibitors, HCV, HIV, co-infection, non invasive liver fibrosis test, seroclearence

#### **1. Introduction**

Approximate 1/3 of HIV infected patients are also infected with hepatitis C virus (HCV) due to shared routes of transmission.

The clinical implications of this crossroad are important and challenging issues regarding the evaluation and management of the co-infected patient.

Patients with HIV and HCV infection have higher risk for developing cirrhosis, hepatic decompensation, increased rates of end-stage liver diseases, hepatocellular carcinoma and shortened lifespan after hepatic decompensation.

#### **2. Virology**

There are similarities by virological point of view for these two viruses: HIV and HCV. Although both HIV and HCV are single-stranded RNA viruses with worldwide distribution, that can result in chronic, subclinical infection, they differ with regard to several important characteristics. HCV is a *flavivirus*, which does not replicate through a DNA-intermediate, as retroviruses do. This allows the possibility of eradication of HCV. HIV viral production rates are approximate 1010 virions per day with half life less than 6 hours and this production is even greater for HCV with production of 1012 virions per day and average virirons half-life 27 hours [1]. Details of the HCV replicative process are still not well known.

In chronic mono-infection with hepatitis C virus or HIV is maintained a viral load relatively stable as a "set point" over long periods of time. Virus specific T-cell responses play a role in the control of virus during chronic HCV.

In co-infection HIV and HCV, HCV RNA levels increase after HIV seroconversion, and continue to increase over time, different from HCV mono-infection. Quantitative loss of memory lymphocytes that occurs in HIV infection could potentially be responsible for the elevated HCV RNA levels, observed in co-infected patients [2]. In combined infection, HCV viral load is related with level of immunosuppression (inversely correlated with CD4 counts), and can increase with heavy alcohol use and transient with the antiretroviral therapy initiation [3]. HIV by himself can increase HCV replication due to gp120 protein (HIV envelope protein) through engagement of cellular co-receptors of HIV (ie, CXCR4 or CCR5) [4].

In addition to quantitative changes of T-cells, HIV may induce qualitative defects in immune responses through alteration of cytokine secretion profiles, and/ or dendritic cell function. Innate effectors, such as natural killer (NK) cells and natural killer T (NKT) cells, also mediate antiviral defenses. Disruption of NK cell function such as increased activation or decreased cytokine secretion induced by HIV-1 could also be responsible for the development of chronic HCV [5, 6].

HIV replicates in CD4+ T-cells as well in many cell types. There are controversial data regarding HCV replicates in extrahepatic sites, a study suggests peripheral blood mononuclear cells (PBMCs) [7]. Some studies have suggested that HCV RNA replication in PBMCs may occur in patients with HIV/HCV co-infection, but not in those with HCV alone [8]. The mechanism for the relapse of HCV viral load after HIV treatment discontinuation can be HCV replication in dendritic cells or PBMCs [9].

The higher rates of perinatal HCV transmission in co-infected patients can be explained by the fact that HCV has been isolated from the cervico-vaginal lavage fluid in HIV HCV positive women (not in HCV positive alone) [10].

After introduction of directly acting agents against HCV (DAA) it was demonstrated the potential drug resistance for HCV parallels as in HIV, resistance mutation to specific polymerase and protease HCV inhibitors [11].

#### **3. Epidemiology**

Since both infections have similar routes of transmission, co-infection HIV and HCV is common. The prevalence of co-infection varies by geographic areas, across risk groups, by route of transmission. Also the sequence of infection depends by transmission route.

HCV infection is transmitted by **percutaneous route** with highest rates in people who inject drugs (PWID) and hemophiliacs. The risk of **post-transfusion** HCV infection deeply decreases. Injection drug use is the most important route of HCV transmission, approximately 80% of HIV persons with history of injection

**69**

*The Influence of Protease Inhibitors on the Evolution of Hepatitis C in Patients with HIV…*

MSM with declining after DAAs but high rate of reinfection.

women who are infected with HCV alone [16].

sion compared with patients with HCV alone.

pathogenic role in mediating liver fibrosis [18].

been associated with fibrosis progression [22].

exposure in **health care workers**.

**4. Pathophysiology**

development of fibrosis [17].

drug use are infected with HCV, and they usually acquire HCV before HIV infection while men who have sex with men (MSM) typically are infected with HIV before

HIV is much easily transmissible via **sexual intercourse** than HCV. In heterosexual partners the prevalence of HCV co-infection is estimated as 4% in persons whose main HIV exposure risk is heterosexual sex with multiple partners. Globally, is estimated a 6.4% of HCV/HIV co-infection prevalence among MSM, with variations depending on the geographic region [13]. In MSM, HCV acquisition is associated with unprotected anal intercourse, group sex, fisting and recreational drugs [14]. HCV transmission may be increased by mucosal injury and/or concomitant other sexually transmitted diseases [15]. Ongoing HCV transmission is occurring in

Regarding **perinatal** transmission of HCV, vertical transmission of HCV seems

There are rare reported cases of acquisition HIV and HCV via percutaneous

Patients with co-infection HIV/HCV have higher rates of liver fibrosis progres-

In patients with HIV, liver fibrosis progression is linked to week cellular immune

responses to HCV antigens. The cellular immune response to viral infection is linked to CD8+ T-cell responses and in HIV infection there is a decreases number of CD4 cells, functional impairment of CD4 and CD8 cells and a down-regulation of a co-stimulatory molecule necessary for lymphocyte activation CD28. These observations explain the link between liver progression and advanced immunosuppression. Also, liver progression can be determined by chronic immune activation through

increased levels of pro-inflammatory cytokines, secondary to HIV infection. Kupffer cell depletion is associated with CD4 cell decline and may be related to

In HCV related liver fibrosis, activated hepatic stellate cells (HSCs) mediate collagen formation. There levels were associated with T cell immune activation and increased gene expression of interleukin-15. In HIV/HCV patients IL-15 play a

In normal hepatocytes apoptosis is mediated by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Glycoproteins of HIV (gp120) through upreg-

HCV-associated proinflammatory cytokines may contribute to liver fibrosis

In acute HCV infection, patients with HIV, especially those with low CD4

In co-infected patients there is a much more rapid rate of progression to cirrhosis than in HCV alone [20]. The prevalence of extensive liver fibrosis was higher in coinfected patients [21]. Non-invasive assessments of liver fibrosis can be used more frequently and these also suggested more rapid fibrosis progression in coinfection but this can be related with the degree of HIV-immunosuppression.

In coinfection, as in monoinfection, some patients clinical characteristics: older age, diabetes, alcohol consumption, diabetes, obesity, elevated liver enzymes, have

ulation of TRAIL-mediated apoptosis triggered to hepatocytes death [19].

progression and these may have a damaging effect on HIV disease [18].

counts, have lower rates of spontaneous virologic clearance.

to be facilitated by HIV co-infection. Maternal co-infection increases the risk of vertical HCV transmission to their infants with about 2.82 fold more than for

*DOI: http://dx.doi.org/10.5772/intechopen.96282*

HCV infection [12].

*The Influence of Protease Inhibitors on the Evolution of Hepatitis C in Patients with HIV… DOI: http://dx.doi.org/10.5772/intechopen.96282*

drug use are infected with HCV, and they usually acquire HCV before HIV infection while men who have sex with men (MSM) typically are infected with HIV before HCV infection [12].

HIV is much easily transmissible via **sexual intercourse** than HCV. In heterosexual partners the prevalence of HCV co-infection is estimated as 4% in persons whose main HIV exposure risk is heterosexual sex with multiple partners. Globally, is estimated a 6.4% of HCV/HIV co-infection prevalence among MSM, with variations depending on the geographic region [13]. In MSM, HCV acquisition is associated with unprotected anal intercourse, group sex, fisting and recreational drugs [14]. HCV transmission may be increased by mucosal injury and/or concomitant other sexually transmitted diseases [15]. Ongoing HCV transmission is occurring in MSM with declining after DAAs but high rate of reinfection.

Regarding **perinatal** transmission of HCV, vertical transmission of HCV seems to be facilitated by HIV co-infection. Maternal co-infection increases the risk of vertical HCV transmission to their infants with about 2.82 fold more than for women who are infected with HCV alone [16].

There are rare reported cases of acquisition HIV and HCV via percutaneous exposure in **health care workers**.

#### **4. Pathophysiology**

*Advances in Hepatology*

There are similarities by virological point of view for these two viruses: HIV and HCV. Although both HIV and HCV are single-stranded RNA viruses with worldwide distribution, that can result in chronic, subclinical infection, they differ with regard to several important characteristics. HCV is a *flavivirus*, which does not replicate through a DNA-intermediate, as retroviruses do. This allows the possibility of eradication of HCV. HIV viral production rates are approximate 1010 virions per day with half life less than 6 hours and this production is even greater for HCV with production of 1012 virions per day and average virirons half-life 27 hours [1]. Details

In chronic mono-infection with hepatitis C virus or HIV is maintained a viral load relatively stable as a "set point" over long periods of time. Virus specific T-cell

In co-infection HIV and HCV, HCV RNA levels increase after HIV seroconversion, and continue to increase over time, different from HCV mono-infection. Quantitative loss of memory lymphocytes that occurs in HIV infection could potentially be responsible for the elevated HCV RNA levels, observed in co-infected patients [2]. In combined infection, HCV viral load is related with level of immunosuppression (inversely correlated with CD4 counts), and can increase with heavy alcohol use and transient with the antiretroviral therapy initiation [3]. HIV by himself can increase HCV replication due to gp120 protein (HIV envelope protein) through engagement of cellular co-receptors of HIV (ie, CXCR4 or CCR5) [4]. In addition to quantitative changes of T-cells, HIV may induce qualitative defects in immune responses through alteration of cytokine secretion profiles, and/ or dendritic cell function. Innate effectors, such as natural killer (NK) cells and natural killer T (NKT) cells, also mediate antiviral defenses. Disruption of NK cell function such as increased activation or decreased cytokine secretion induced by HIV-1 could also be responsible for the development of chronic HCV [5, 6].

HIV replicates in CD4+ T-cells as well in many cell types. There are controversial data regarding HCV replicates in extrahepatic sites, a study suggests peripheral blood mononuclear cells (PBMCs) [7]. Some studies have suggested that HCV RNA replication in PBMCs may occur in patients with HIV/HCV co-infection, but not in those with HCV alone [8]. The mechanism for the relapse of HCV viral load after HIV treatment discontinuation can be HCV replication in dendritic cells or PBMCs [9]. The higher rates of perinatal HCV transmission in co-infected patients can be explained by the fact that HCV has been isolated from the cervico-vaginal lavage

After introduction of directly acting agents against HCV (DAA) it was demonstrated the potential drug resistance for HCV parallels as in HIV, resistance muta-

Since both infections have similar routes of transmission, co-infection HIV and HCV is common. The prevalence of co-infection varies by geographic areas, across risk groups, by route of transmission. Also the sequence of infection depends by

HCV infection is transmitted by **percutaneous route** with highest rates in people who inject drugs (PWID) and hemophiliacs. The risk of **post-transfusion** HCV infection deeply decreases. Injection drug use is the most important route of HCV transmission, approximately 80% of HIV persons with history of injection

fluid in HIV HCV positive women (not in HCV positive alone) [10].

tion to specific polymerase and protease HCV inhibitors [11].

of the HCV replicative process are still not well known.

responses play a role in the control of virus during chronic HCV.

**2. Virology**

**68**

**3. Epidemiology**

transmission route.

Patients with co-infection HIV/HCV have higher rates of liver fibrosis progression compared with patients with HCV alone.

In patients with HIV, liver fibrosis progression is linked to week cellular immune responses to HCV antigens. The cellular immune response to viral infection is linked to CD8+ T-cell responses and in HIV infection there is a decreases number of CD4 cells, functional impairment of CD4 and CD8 cells and a down-regulation of a co-stimulatory molecule necessary for lymphocyte activation CD28. These observations explain the link between liver progression and advanced immunosuppression.

Also, liver progression can be determined by chronic immune activation through increased levels of pro-inflammatory cytokines, secondary to HIV infection. Kupffer cell depletion is associated with CD4 cell decline and may be related to development of fibrosis [17].

In HCV related liver fibrosis, activated hepatic stellate cells (HSCs) mediate collagen formation. There levels were associated with T cell immune activation and increased gene expression of interleukin-15. In HIV/HCV patients IL-15 play a pathogenic role in mediating liver fibrosis [18].

In normal hepatocytes apoptosis is mediated by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Glycoproteins of HIV (gp120) through upregulation of TRAIL-mediated apoptosis triggered to hepatocytes death [19].

HCV-associated proinflammatory cytokines may contribute to liver fibrosis progression and these may have a damaging effect on HIV disease [18].

In acute HCV infection, patients with HIV, especially those with low CD4 counts, have lower rates of spontaneous virologic clearance.

In co-infected patients there is a much more rapid rate of progression to cirrhosis than in HCV alone [20]. The prevalence of extensive liver fibrosis was higher in coinfected patients [21]. Non-invasive assessments of liver fibrosis can be used more frequently and these also suggested more rapid fibrosis progression in coinfection but this can be related with the degree of HIV-immunosuppression.

In coinfection, as in monoinfection, some patients clinical characteristics: older age, diabetes, alcohol consumption, diabetes, obesity, elevated liver enzymes, have been associated with fibrosis progression [22].

#### **5. Effect of antiretroviral treatment (ART) on HCV progression**

There are studies that suggested a decline in liver-related mortality associated with a potent ART introduction which also slows the rates of fibrosis progression, due to immune reconstruction [23]. A cross-sectional study demonstrated a lower necroinflammatory activity on liver biopsy in HIV viral suppressed ART patients and another study showed an increased risk of fibrosis progression in those patients with ART interruption [24, 25]. There is a decrease in AIDS and non-AIDS related morbidity and mortality in HIV patients with early ART initiation and this approach is important especially in HIV/HCV patients. There is evidence that use of ART partially restores T-cell responses to core HCV peptides. Successful response to ART among HIV/HCV patients is associated with increased cellular immune responses to HCV infection, long-term reduction in HCV RNA levels and with HCV clearance [26].

Drug induced liver injury (DILI) is more common in HIV/HCV coinfection following ART. Even liver toxicity is more common in patients with chronic viral hepatitis the benefit of ART exceeds the risk of liver injury. Some studies found an increased risk not for all ART regimens, only for some antiretroviral agents, such as ritonavir or nevirapine [27, 28].

The role of particular drug or antiretroviral class in liver progression rates is questionable, there are conflicting data. In a retrospective analysis, the authors observed that along with young age at infection, heavy alcohol use, and a low CD4 count, patients whose ART regimen did not contain a protease inhibitor (PI) had higher inflammation and fibrosis scores when compared to those who took a PI as part of their ART regimen [29]. In another retrospective analysis of coinfected patients, no significant differences in the proportion of severe fibrosis (approximately 25%) were observed between those on an non-nucleoside reverse transcriptase inhibitors (NNRTI), a PI, or both [30]. Therefore, specific PI or NNRTI use may not be associated with evident histological benefit or obvious histological worsening of HCV disease.

There are conflicting studies regarding the role of HCV in clinical progression of HIV disease. Some studies have suggested that co-infected patients have an increased progression to AIDS, as well as a decrease in survival from the time of diagnosis of HIV and AIDS [31, 32].

#### **6. Treatment of chronic hepatitis C virus infection in the patient with HIV**

The goal of HCV antiviral treatment is to cure the infection, characterized by achievement of a sustained virological response (SVR) defined as an undetectable HCV RNA at week 12 to 24 after the end of treatment. Thus, an effective cure is associated with substantial reduction in liver-related mortality and morbidity and reduced incidence of hepatocellular carcinoma.

HIV/HCV coinfected patients had lower response rates to HCV treatment with peginterferon and ribavirin regimens compared with individuals without HIV. They have comparable SVR rates with DAA-regimens as HCV-monoinfected patients. Eradication of HCV infection may reduce the antiretrovirus-associated DILI.

The decision of optimal regimen and timing vary based upon: genotype, the stage of liver disease, prior treatment history, drug interaction and some medical and social priorities.

Because of the more rapid progression of liver fibrosis in the settings of HIV infection, coinfected patients should be prioritized for HCV antiviral therapy and

**71**

*The Influence of Protease Inhibitors on the Evolution of Hepatitis C in Patients with HIV…*

another reason to prioritize HCV treatment is cirrhosis and bridging fibrosis. With highly effective interferon-free regimens (DAA), curative all-oral treatment is possible also for those patients with coinfection. There is a low incidence of adverse events and high efficacy and that means that almost all patients can benefit from

All HIV patients should be evaluated for chronic HCV infection using a third

Evaluation for coinfected patients for HCV treatment, by the point of view of HCV infection, is similar to those monoinfected. Prior to treatment evaluation should focus on these factors: HCV genotype, viral resistance testing for certain populations, history of prior treatment, assessment of liver fibrosis stage using noninvasive tests for fibrosis or liver biopsy, history, physical and basic laboratory

Timing of HCV therapy in relation to ART initiation in ART-naïve patients is important and that it will be discussed below. For special population, such as those with decompensate liver diseases, the treatment should be established only in

For HIV/HCV coinfected patients whom are considered to receive HCV treatment, the appropriate antiretroviral treatment regimen used should not have serious drug interaction with HCV antiviral agents. Another management issue in coinfected patients is the timing of antiretroviral therapy initiation or regimen switch. It is not recommended an ART interruption to allow HCV antiviral therapy [33]. In ART-naive HIV/HCV patients is preferable to start ART first and begin HCV treatment later. HIV/HCV patients should be initiated on ART for HIV disease without taking into account their CD4 cell count [34]. In selection of ART regimen should be taken into account the potential drug–drug interactions with HCV antivirals. It is recommended to initiate ART approximately 4 to 6 weeks before starting HCV therapy for two reasons: initiation of ART first allows assessment of tolerability and adverse effects of ART alone and the second reasons is an improved HCV outcome, by suppression HIV viral load by ART treatment through restoration

In ART-experienced HIV/HCV patients, who achieved HIV viral suppression on an ART well tolerate regimen, should continue the regimen, if it does not have significant drug interactions with the HCV treatment selected. A regimen switch may be necessary if ART regimen components cannot be used with HCV antiviral drugs. In failure to suppress HIV or adverse effects or intolerance to an ART regimen, the regimen switch should be indicated. In this case should be taken into account in selection of a new ART regimen potential drug interaction with HCV-antivirals, in addition to all specific recommendations that appeared in the choice of ART regimen in treatment-experienced patients. In ART regimen switches, prior antiretroviral history drugs and resistance profiles should be studied, to ensure that the new regimen is active, with two or three fully active antiretroviral drugs. The treatment should be initiated after 4 to 6 weeks after ART regimen switch by the same reasons as in ART-naive patients. Additionally, HIV RNA should be determined at 4 to 6 weeks after the switch to ensure that the new regimen maintains HIV viral suppression. If it is wished to switch back, the new ART regimen to the original ART

), risk factors for HCV acquisition

generation enzyme immunoassay. Patients found to be HCV positive should undergo quantitative HCV RNA testing to confirm the presence of viremia. HIV patients who are found to be HCV seronegative but if they are with advanced

*DOI: http://dx.doi.org/10.5772/intechopen.96282*

immnuosuppression (CD4 counts<100 cells/mm3

of immune response or other effects [35].

or elevated liver enzymes should undergo HCV-RNA testing.

tests, evaluation for conditions that might affect the therapy.

**6.1 Management of antiretroviral treatment in coinfected patients**

specialized center with expertise in managing HIV/HCV coinfection.

HCV treatment.

*The Influence of Protease Inhibitors on the Evolution of Hepatitis C in Patients with HIV… DOI: http://dx.doi.org/10.5772/intechopen.96282*

another reason to prioritize HCV treatment is cirrhosis and bridging fibrosis. With highly effective interferon-free regimens (DAA), curative all-oral treatment is possible also for those patients with coinfection. There is a low incidence of adverse events and high efficacy and that means that almost all patients can benefit from HCV treatment.

All HIV patients should be evaluated for chronic HCV infection using a third generation enzyme immunoassay. Patients found to be HCV positive should undergo quantitative HCV RNA testing to confirm the presence of viremia. HIV patients who are found to be HCV seronegative but if they are with advanced immnuosuppression (CD4 counts<100 cells/mm3 ), risk factors for HCV acquisition or elevated liver enzymes should undergo HCV-RNA testing.

Evaluation for coinfected patients for HCV treatment, by the point of view of HCV infection, is similar to those monoinfected. Prior to treatment evaluation should focus on these factors: HCV genotype, viral resistance testing for certain populations, history of prior treatment, assessment of liver fibrosis stage using noninvasive tests for fibrosis or liver biopsy, history, physical and basic laboratory tests, evaluation for conditions that might affect the therapy.

#### **6.1 Management of antiretroviral treatment in coinfected patients**

Timing of HCV therapy in relation to ART initiation in ART-naïve patients is important and that it will be discussed below. For special population, such as those with decompensate liver diseases, the treatment should be established only in specialized center with expertise in managing HIV/HCV coinfection.

For HIV/HCV coinfected patients whom are considered to receive HCV treatment, the appropriate antiretroviral treatment regimen used should not have serious drug interaction with HCV antiviral agents. Another management issue in coinfected patients is the timing of antiretroviral therapy initiation or regimen switch. It is not recommended an ART interruption to allow HCV antiviral therapy [33].

In ART-naive HIV/HCV patients is preferable to start ART first and begin HCV treatment later. HIV/HCV patients should be initiated on ART for HIV disease without taking into account their CD4 cell count [34]. In selection of ART regimen should be taken into account the potential drug–drug interactions with HCV antivirals. It is recommended to initiate ART approximately 4 to 6 weeks before starting HCV therapy for two reasons: initiation of ART first allows assessment of tolerability and adverse effects of ART alone and the second reasons is an improved HCV outcome, by suppression HIV viral load by ART treatment through restoration of immune response or other effects [35].

In ART-experienced HIV/HCV patients, who achieved HIV viral suppression on an ART well tolerate regimen, should continue the regimen, if it does not have significant drug interactions with the HCV treatment selected. A regimen switch may be necessary if ART regimen components cannot be used with HCV antiviral drugs. In failure to suppress HIV or adverse effects or intolerance to an ART regimen, the regimen switch should be indicated. In this case should be taken into account in selection of a new ART regimen potential drug interaction with HCV-antivirals, in addition to all specific recommendations that appeared in the choice of ART regimen in treatment-experienced patients. In ART regimen switches, prior antiretroviral history drugs and resistance profiles should be studied, to ensure that the new regimen is active, with two or three fully active antiretroviral drugs. The treatment should be initiated after 4 to 6 weeks after ART regimen switch by the same reasons as in ART-naive patients. Additionally, HIV RNA should be determined at 4 to 6 weeks after the switch to ensure that the new regimen maintains HIV viral suppression. If it is wished to switch back, the new ART regimen to the original ART

*Advances in Hepatology*

clearance [26].

ritonavir or nevirapine [27, 28].

worsening of HCV disease.

**with HIV**

and social priorities.

diagnosis of HIV and AIDS [31, 32].

reduced incidence of hepatocellular carcinoma.

**5. Effect of antiretroviral treatment (ART) on HCV progression**

There are studies that suggested a decline in liver-related mortality associated with a potent ART introduction which also slows the rates of fibrosis progression, due to immune reconstruction [23]. A cross-sectional study demonstrated a lower necroinflammatory activity on liver biopsy in HIV viral suppressed ART patients and another study showed an increased risk of fibrosis progression in those patients with ART interruption [24, 25]. There is a decrease in AIDS and non-AIDS related morbidity and mortality in HIV patients with early ART initiation and this approach is important especially in HIV/HCV patients. There is evidence that use of ART partially restores T-cell responses to core HCV peptides. Successful response to ART among HIV/HCV patients is associated with increased cellular immune responses to HCV infection, long-term reduction in HCV RNA levels and with HCV

Drug induced liver injury (DILI) is more common in HIV/HCV coinfection following ART. Even liver toxicity is more common in patients with chronic viral hepatitis the benefit of ART exceeds the risk of liver injury. Some studies found an increased risk not for all ART regimens, only for some antiretroviral agents, such as

The role of particular drug or antiretroviral class in liver progression rates is questionable, there are conflicting data. In a retrospective analysis, the authors observed that along with young age at infection, heavy alcohol use, and a low CD4 count, patients whose ART regimen did not contain a protease inhibitor (PI) had higher inflammation and fibrosis scores when compared to those who took a PI as part of their ART regimen [29]. In another retrospective analysis of coinfected patients, no significant differences in the proportion of severe fibrosis (approximately 25%) were observed between those on an non-nucleoside reverse transcriptase inhibitors (NNRTI), a PI, or both [30]. Therefore, specific PI or NNRTI use may not be associated with evident histological benefit or obvious histological

There are conflicting studies regarding the role of HCV in clinical progression of HIV disease. Some studies have suggested that co-infected patients have an increased progression to AIDS, as well as a decrease in survival from the time of

The goal of HCV antiviral treatment is to cure the infection, characterized by achievement of a sustained virological response (SVR) defined as an undetectable HCV RNA at week 12 to 24 after the end of treatment. Thus, an effective cure is associated with substantial reduction in liver-related mortality and morbidity and

HIV/HCV coinfected patients had lower response rates to HCV treatment with peginterferon and ribavirin regimens compared with individuals without HIV. They have comparable SVR rates with DAA-regimens as HCV-monoinfected patients. Eradication of HCV infection may reduce the antiretrovirus-associated DILI. The decision of optimal regimen and timing vary based upon: genotype, the stage of liver disease, prior treatment history, drug interaction and some medical

Because of the more rapid progression of liver fibrosis in the settings of HIV infection, coinfected patients should be prioritized for HCV antiviral therapy and

**6. Treatment of chronic hepatitis C virus infection in the patient** 

**70**

regimen, following completion of HCV treatment, this should be delayed until at least two weeks after completion of HCV treatment, to ensure clearance of the HCV antivirals [34].

#### **6.2 HCV regimen selection in coinfected patients**

The efficacy of DAA regimens among HIV/HCV coinfected patients it seems to be comparable to that in HCV monoinfected patients, the regimen selection decisions are similar for these two groups.

The HCV selection regimen is based on genotype, prior HCV treatment, the stage of liver fibrosis and in rare cases by the presence of baseline NS5A inhibitor resistance associated substitutions. In co-infected patients, the HCV regimen drug interaction with HIV antiretroviral is the major consideration in selection of HCV regimen.

The regimen options for coinfected patients with a particular genotype are the same as those for HCV monoinfected patients with the same genotype. Potential drug interactions with antiretroviral regimen is the major consideration factor that decide between the several regimens available for a specific genotype. There are regimens that have been studied in coinfected patients.

#### *6.2.1 Genotype 1 HCV infection*

	- Sofosbuvir-velpatasvir-voxilaprevir, a regimen reserved for patients who failed on certain DAA-regimen, can be used also for 8 weeks in naïve patients, has not been studied in coinfected patients but is thought to be the same efficient as in monoinfected patients

**73**

*The Influence of Protease Inhibitors on the Evolution of Hepatitis C in Patients with HIV…*

○ Daclatasvir plus sofosbuvir is highly effective for genotype 1, 12 weeks of treatment in naïve or experienced- coinfected patients. For these regimens, allowed ART agents included darunavir, atazanavir, or lovinavir, each ritonavir-boosted, efavirenz, rilpivirine, raltegravir and dolutegravir. When it is used with specific asntiretrovirals, the dose adjustment of daclatasvir is

○ Daclatasvir plus asunaprevir is available in Japan for genotype 1b infection.

• Glecaprevir-pibrentasvir 8 weeks in non-cirrothic patients, 12 weeks for patients with compensated cirrhosis [38]. The choice between them depends

• Sofosbuvir- velpatasvir-voxilaprevir – reserved for patients who previously failed on an certain DAA regimen, 8 weeks treatment, has not been studied for

Administration and dosing of these regimens in coinfected patients are similar

• Glecaprevir-pibrentasvir for 8 to 16 weeks depending on treatment history and

• Sofosbuvir- velpatasvir-voxilaprevir – reserved for patients who previously failed on an certain DAA regimen,, has not been studied for HIV/HCV patients

The choice between them depends on drug interaction. The studies are in a

Studies in limited numbers of coinfected patients have demonstrated good efficacy with various regimens as those recommended for HCV-monoinfected patients.

• Sofosbuvir-velpatasvir with or without ribavirin for 12 weeks.

*6.2.2 Genotype 2 infection: highly effective options, formally evaluated for* 

*DOI: http://dx.doi.org/10.5772/intechopen.96282*

• Daclatasvir combinations

needed.

*coinfected patients*

on drug interaction.

HIV/HCV patients

to monoinfection.

*6.2.3 Genotype 3 infection*

presence of cirrhosis

• Daclatasvir plus sofosbuvir

*6.2.4 Genotype 4, 5 and 6 infection*

• Ledipasvir-sofosbuvir

• Elbasvir-grazoprevir

• Glecaprevir-pibrentasvir

limited number of coinfected patients [37, 38].

• Sofosbuvir-velpatasvir 12 weeks [37].

*The Influence of Protease Inhibitors on the Evolution of Hepatitis C in Patients with HIV… DOI: http://dx.doi.org/10.5772/intechopen.96282*

#### • Daclatasvir combinations

*Advances in Hepatology*

antivirals [34].

regimen, following completion of HCV treatment, this should be delayed until at least two weeks after completion of HCV treatment, to ensure clearance of the HCV

The efficacy of DAA regimens among HIV/HCV coinfected patients it seems to be comparable to that in HCV monoinfected patients, the regimen selection deci-

The HCV selection regimen is based on genotype, prior HCV treatment, the stage of liver fibrosis and in rare cases by the presence of baseline NS5A inhibitor resistance associated substitutions. In co-infected patients, the HCV regimen drug interaction with HIV antiretroviral is the major consideration in selection of HCV regimen. The regimen options for coinfected patients with a particular genotype are the same as those for HCV monoinfected patients with the same genotype. Potential drug interactions with antiretroviral regimen is the major consideration factor that decide between the several regimens available for a specific genotype. There are

• Elbasvir-grazoprevir- high efficacy of this regimen in HIV/HCV patients. Analysis in monoinfected patients has suggested an association between lower SVR rates and pre-existing variations in the genotype's 1 NS5A inhibitor sequence. In genotype-1a infected patients is recommended testing for these resistance-associated substitution, and, if present, adding ribavirin and

• Sofosbuvir- velpatasvir- is a highly effective pangenotypic regimen, for

12 weeks, the SVR rates are high regardless cirrhosis or treatment history [37].

○ Sofosbuvir-velpatasvir-voxilaprevir, a regimen reserved for patients who failed on certain DAA-regimen, can be used also for 8 weeks in naïve patients, has not been studied in coinfected patients but is thought to be the

• Glecaprevir-pibrentasvir, is also a potent effective pangenotypic regimen, with high efficiency in coinfected patients treatment for 8 or 12 weeks [38].

• Ledipasvir-sofosbuvir- is highly effective in several studies in coinfected patients treatment naive or experienced, for 12 weeks, with high SVR overall

• Ombitasvir- paritaprevir- ritonavir plus dasabuvir- this regimen with or without ribavirin is highly effective for coinfected patients with genotype1, given for 12 to 24 weeks (depending on the infection subtype and the presence

• Simeprevir and sofosbuvir – effective in HIV/HCV patients with cirrhosis who had failed to a prior regimen, given 16 or 24 weeks. (telaprevir plus peginterferon and ribavirin) [41]. The SVR rates in real-life are higher in patients

even in patients with cirrhosis or prior treatment failure [39].

**6.2 HCV regimen selection in coinfected patients**

regimens that have been studied in coinfected patients.

extended to 16 weeks the duration of treatment [35, 36].

same efficient as in monoinfected patients

without these negative predictors of response.

sions are similar for these two groups.

*6.2.1 Genotype 1 HCV infection*

of cirrhosis) [40].

**72**


#### *6.2.2 Genotype 2 infection: highly effective options, formally evaluated for coinfected patients*


Administration and dosing of these regimens in coinfected patients are similar to monoinfection.

#### *6.2.3 Genotype 3 infection*


The choice between them depends on drug interaction. The studies are in a limited number of coinfected patients [37, 38].

#### *6.2.4 Genotype 4, 5 and 6 infection*

Studies in limited numbers of coinfected patients have demonstrated good efficacy with various regimens as those recommended for HCV-monoinfected patients.


#### **6.3 Potential drug interaction with ART**

When assessing a HIV/HCV patient for HCV treatment there some important drug interactions to be considered.


**75**

**Table 1.** *Liver fibrosis.*

*The Influence of Protease Inhibitors on the Evolution of Hepatitis C in Patients with HIV…*

Patients should be monitored for side effects and adherence, viral loads responses on therapy and also depending on ART regimen all the tests needed for

In our hospital, we are treating patients with HIV infection for about 20 years, with a history of long-term antiretroviral regimens which include protease inhibitors (PI). The newly regimens for HCV treatment with direct-acting antivirals contains protease inhibitors (PI) and ritonavir for HCV infection, like in HIV infection. In our clinic there are 4.33% patients HIV/HCV coinfected, this incidence is similar to HCV in general population in Romania. In a previous study using noninvasive methods FibroScan (transient elasthography) we demonstrated that 84.6% of HIV patients had mild or no fibrosis, 15.4% had moderate–severe fibrosis, and no cirrhosis [42]. We also demonstrated the concordance between noninvasive fibrosis evaluation methods Fibroscan, APRI and FIB-4 score for HIV [43, 44] and

We evaluated the patients HIV/HCV coinfected under combined antiretroviral treatment containing PI boosted with ritonavir in terms of immunological and virological status (for both HIV and HCV infection) and also liver disease. Patients were evaluated for liver damage by non-invasive methods, APRI score and FIB-4. By immunological HIV status 64.5% have CD4 ≥ 500cells/mm3, 29.03% have

<40 copies/ml in 70% of cases, 11% presented less than 100 copies/ml, and 19% of

A high proportion of these HIV/HCV co-infected patients had no detectable viremia, higher than other studies published which may be explained by the fact that these patients have had HCV clearance, spontaneous or induced by the antiret-

HIV APRI 84.6 15.4 0

HIV/HCV APRI 69 24 7

FIB-4 82.0 18.0 0

FIB-4 77 16 7

Using APRI score 69% of HIV/HCV patients have APRI < 0.5, representing mild or no fibrosis, 24% moderate or severe fibrosis and 7%, APRI > 1.5 corresponding to cirrhosis. The same results are when we used FIB-4 score: 77% no/mild fibrosis, (FIB4 < 1.45), 16% moderate/severe fibrosis, 7% cirrhosis (FIB-4 > 3.25. We have shown that a small percentage of patients have severe liver damage but significantly higher in HIV HCV co-infection than in mono HIV infected persons (**Table 1**). In another study on these cohort 34% of coinfected patients have undetectable HCV viral load without any HCV regimen only the same exposure to PI, (ritonavirboosted lopinavir majority or other PI) [45]. This seroclearence can be explained by immune reconstruction induced by antiretroviral treatment or by direct antiviral

patients, noncompliant to ART treatment, with detectable HIV viral load.

, and 6.45% CD4 ≤ 200cells/mm3. HIV viral load was

**Fibrosis No/mild (%) Moderate/severe (%) Cirrhosis (%)**

in literature these are used in coinfected HIV/HCV patients monitoring.

*DOI: http://dx.doi.org/10.5772/intechopen.96282*

evaluate side effects or toxicity.

**7. Personal contribution**

CD4 = 200-499cells/mm3

effect of PIs on HCV infection.

**Infection Non-invasive liver** 

**fibrosis tests**

roviral therapy.

*The Influence of Protease Inhibitors on the Evolution of Hepatitis C in Patients with HIV… DOI: http://dx.doi.org/10.5772/intechopen.96282*

Patients should be monitored for side effects and adherence, viral loads responses on therapy and also depending on ART regimen all the tests needed for evaluate side effects or toxicity.

#### **7. Personal contribution**

*Advances in Hepatology*

**6.3 Potential drug interaction with ART**

combination with ledipasvir-sofosbuvir.

emtricitabine, TAF, rilpivirine.

clinical relevant interactions.

contained in HCV regimen.

advised.

drug interactions to be considered.

adverse events.

When assessing a HIV/HCV patient for HCV treatment there some important

• ribavirin. The interaction between it and antiretroviral agents include direct interaction but also a combination that potentiate adverse effects (with

• sofosbuvir. Have few drug interactions with antiretroviral agents. In clinical studies was used in combination with tenofovir disoproxil fumarate- emtricitabine (TDF-EMT), efavirenz, darunavir or atazanavir boosted with ritonavir, raltegravir and rilpivirine, without any evidence of decreased efficacyor

• ledipasvir- sofosbuvir. It is available only as a fixed-dose combination.

Co-administration with tenofovir disoproxil fumarate (TDF), increased levels of tenofovir. Co-admistration with tenofovir alafenamide (TAF) does not elevate plasma levels of tenofovir, that's why we can switch patients from TDF to TAF containing regimen when planning a treatment with ledipasvir- sofosbuvir. There are specific options for different TDF-containing antiretrovirals in

• sofosbuvir –velpatasvir is only available in fixed-dose combination. There are no evidence of interaction or adverse events in combination with abacavir, atazanavir, darunavir, ritonavir, cobicistat, elvitegravir, raltegravir, lamivudine,

• glecaprevir-pibrentasvir is available in fixed-dose combination. It was used in studies in combination with tenofovor, abacavirm, lamivudine, emtricitabine, raltegravir, dolutegravir, evitegravir with cobicistat and rilpivirine without

• elbasvir-grazoprevir- is available in fixed-dose combination. Both are primarly metabolized through CYP3A metabolism, thus, coadminsitration with several antiretrovirals is not advised. It can be used in combination with tenofovir, lamivudine, abacavir, emtricitabine, rilpivirine and dolutegravir, raltegravir.

• Ombitasvir-paritaprevir-ritonavir plus dasabuvir. Drug –interactions are expected since all of these agents are substrates and inhibitors of major metabolic enzymes. It was used safely with TDF-FTC and raltegravir, or in combination with atazanavir, when ritonavir boosting was served by ritonavir

• voxilaprevir, is available in fixed-dose combination pills with sofosbuvir and velpatasvir. Voxilaprevir is a substrate and inhibitor of P-glycoprotein, slowly metabolized by CYP34A. Coadministration with several antiretrovirals is not

• daclatasvir is metabolized by CYP3A, thus inducers or inhibitors of these

• simeprevir is oxidatively metabolized by CYP3A. Inducers or inhibitors of

enzyme are expected to modify daclatasvir concentration.

CYP3A are expected to modify simeprevir concentration.

atazanavir- containing ART, patients may develop jaundice).

**74**

In our hospital, we are treating patients with HIV infection for about 20 years, with a history of long-term antiretroviral regimens which include protease inhibitors (PI). The newly regimens for HCV treatment with direct-acting antivirals contains protease inhibitors (PI) and ritonavir for HCV infection, like in HIV infection.

In our clinic there are 4.33% patients HIV/HCV coinfected, this incidence is similar to HCV in general population in Romania. In a previous study using noninvasive methods FibroScan (transient elasthography) we demonstrated that 84.6% of HIV patients had mild or no fibrosis, 15.4% had moderate–severe fibrosis, and no cirrhosis [42]. We also demonstrated the concordance between noninvasive fibrosis evaluation methods Fibroscan, APRI and FIB-4 score for HIV [43, 44] and in literature these are used in coinfected HIV/HCV patients monitoring.

We evaluated the patients HIV/HCV coinfected under combined antiretroviral treatment containing PI boosted with ritonavir in terms of immunological and virological status (for both HIV and HCV infection) and also liver disease. Patients were evaluated for liver damage by non-invasive methods, APRI score and FIB-4.

By immunological HIV status 64.5% have CD4 ≥ 500cells/mm3, 29.03% have CD4 = 200-499cells/mm3 , and 6.45% CD4 ≤ 200cells/mm3. HIV viral load was <40 copies/ml in 70% of cases, 11% presented less than 100 copies/ml, and 19% of patients, noncompliant to ART treatment, with detectable HIV viral load.

Using APRI score 69% of HIV/HCV patients have APRI < 0.5, representing mild or no fibrosis, 24% moderate or severe fibrosis and 7%, APRI > 1.5 corresponding to cirrhosis. The same results are when we used FIB-4 score: 77% no/mild fibrosis, (FIB4 < 1.45), 16% moderate/severe fibrosis, 7% cirrhosis (FIB-4 > 3.25. We have shown that a small percentage of patients have severe liver damage but significantly higher in HIV HCV co-infection than in mono HIV infected persons (**Table 1**).

In another study on these cohort 34% of coinfected patients have undetectable HCV viral load without any HCV regimen only the same exposure to PI, (ritonavirboosted lopinavir majority or other PI) [45]. This seroclearence can be explained by immune reconstruction induced by antiretroviral treatment or by direct antiviral effect of PIs on HCV infection.

A high proportion of these HIV/HCV co-infected patients had no detectable viremia, higher than other studies published which may be explained by the fact that these patients have had HCV clearance, spontaneous or induced by the antiretroviral therapy.


**Table 1.** *Liver fibrosis.*

The immunological and virological HIV status of these undetectable HCV viral load patients was better than in those with detectabile HCV viral load. There are also diferencies regarding PI regimens and duration between these two groups. We have limited experience on DAA treatment in HIV/HCV coinfected patients.

#### **8. Conclusion**

With the growing availability and diversity of direct-acting antiviral combination regimen for HCV treatment, a curative treatment will be possible for majority patients, even those with HIV.

The sustained virologic response rates in coinfected patients treated with DAA are similar with monoinfected patients, with almost the same regimens. These are associated with substantial reductions in liver-related morbidity and mortality. A testing algorithm based on primary care screening (e.g. with APRI, FIB-4) followed by referral for specialty confirmatory testing (e.g, transient elastography) would best fit most practice models.

There are some management issues in HIV/HCV coinfection regarding appropriate antiretroviral regimens and drug interactions with HCV treatment.

With these DAA regimens, as in HIV preexposure prophylaxis (PrEP), maybe we can limit the extension of HCV infections in some risk group of HIV patients.

#### **Conflict of interest**

"The authors declare no conflict of interest."

#### **Author details**

Elena Dumea1,2 and Simona Claudia Cambrea1,2\*

1 Faculty of Medicine, "Ovidius" University, Constanta, Romania

2 Infectious Diseases Clinical Hospital, Constanta, Romania

\*Address all correspondence to: cambrea.claudia@gmail.com

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**77**

*The Influence of Protease Inhibitors on the Evolution of Hepatitis C in Patients with HIV…*

cells of patients coinfected with human immunodeficiency virus type 1: evidence of active replication in monocytes/ macrophages and lymphocytes. J Infect Dis 2000; 181:442. DOI: 10.1086/315283

[9] Blackard JT, Smeaton L, Hiasa Y, et al. Detection of hepatitis C virus (HCV) in serum and peripheralblood mononuclear cells from HCVmonoinfected and HIV/HCV-coinfected persons. J Infect Dis 2005; 192:258. DOI:

[10] Minosse C, Calcaterra S, Abbate I, et al. Possible compartmentalization of hepatitis C viral replication in the genital tract of HIV-1-coinfected women. J Infect Dis 2006; 194:1529.

[11] Gaudieri S, Rauch A, Pfafferott K, et al. Hepatitis C virus drug resistance and immune-driven adaptations: relevance to new antiviral therapy. Hepatology 2009; 49:1069. DOI:

[12] Kim AY, Chung RT. Coinfection with HIV-1 and HCV--a one-two punch. Gastroenterology 2009; 137:795. DOI:

[13] Platt L, Easterbrook P, Gower E, et al. Prevalence and burden of HCV co-infection in people living with HIV: a global systematic review and metaanalysis. Lancet Infect Dis 2016; 16:797. DOI: 10.1016/S1473-3099(15)00485-5

[14] Urbanus AT, van de Laar TJ, Stolte IG, et al. Hepatitis C virus infections among HIV-infected men who have sex with men: an expanding epidemic. AIDS 2009; 23:F1. DOI: 10.1097/QAD.0b013e32832e5631

[15] Tohme RA, Holmberg SD. Is sexual contact a major mode of hepatitis C virus transmission? Hepatology 2010; 52:1497. DOI: 10.1002/hep.23808

10.1053/j.gastro.2009.06.040

10.1086/430949

DOI: 10.1086/508889

10.1002/hep.22773

*DOI: http://dx.doi.org/10.5772/intechopen.96282*

[1] Neumann AU, Lam NP, Dahari H, Gretch D R, Wiley T E, Layden T J, Perelson A S. Hepatitis C viral dynamics in vivo and the antiviral efficacy of interferon-alpha therapy. Science 1998; 282:103. DOI:10.1126/

[2] Thein HH, Yi Q, Dore GJ, et al. Natural history of hepatitis C virus infection in HIV infected individuals and the impact of HIV in the era of highly active antiretroviral therapy: a meta-analysis. AIDS. 2008;22:1979-1991 DOI:10.1097/QAD.0b013e32830e6d51

[3] Netski DM, Mao Q, Ray SC, Klein RS. Genetic divergence of

[4] Lin W, Weinberg EM, Tai AW, et al. HIV increases HCV replication in a TGF-beta1-dependent manner. Gastroenterology 2008; 134:803. DOI:https://doi.org/10.1053/j.

[5] Khakoo SI, Thio CL, Martin MP, et al. HLA and NK cell inhibitory receptor genes in resolving hepatitis C virus infection. Science. 2004; 305:872- 874. DOI:10.1126/science.1097670

[6] Iannello A, Debbeche O, Samarani S, et al. Antiviral NK cell responses in HIV infection: viral strategies for evasion and lessons for immunotherapy and vaccination. J Leukoc Biol. 2008;84:27-

[7] Blackard JT, Kemmer N, Sherman KE.

49 DOI: 10.1189/jlb.0907649

Extrahepatic replication of HCV: insights into clinical manifestations and biological consequences. Hepatology 2006; 44:15. DOI:10.1002/hep.21283

[8] Laskus T, Radkowski M, Piasek A, et al. Hepatitis C virus in lymphoid

QAI.0b013e3181869a6f

gastro.2008.01.005

hepatitis C virus: the role of HIV-related immunosuppression. J Acquir Immune Defic Syndr 2008; 49:136. DOI:10.1097/

**References**

science.282.5386.103

*The Influence of Protease Inhibitors on the Evolution of Hepatitis C in Patients with HIV… DOI: http://dx.doi.org/10.5772/intechopen.96282*

#### **References**

*Advances in Hepatology*

**8. Conclusion**

patients, even those with HIV.

best fit most practice models.

**Conflict of interest**

**76**

**Author details**

Elena Dumea1,2 and Simona Claudia Cambrea1,2\*

provided the original work is properly cited.

"The authors declare no conflict of interest."

1 Faculty of Medicine, "Ovidius" University, Constanta, Romania

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

The immunological and virological HIV status of these undetectable HCV viral load patients was better than in those with detectabile HCV viral load. There are also diferencies regarding PI regimens and duration between these two groups. We have limited experience on DAA treatment in HIV/HCV coinfected patients.

With the growing availability and diversity of direct-acting antiviral combination regimen for HCV treatment, a curative treatment will be possible for majority

The sustained virologic response rates in coinfected patients treated with DAA are similar with monoinfected patients, with almost the same regimens. These are associated with substantial reductions in liver-related morbidity and mortality. A testing algorithm based on primary care screening (e.g. with APRI, FIB-4) followed by referral for specialty confirmatory testing (e.g, transient elastography) would

There are some management issues in HIV/HCV coinfection regarding appro-

With these DAA regimens, as in HIV preexposure prophylaxis (PrEP), maybe we can limit the extension of HCV infections in some risk group of HIV patients.

priate antiretroviral regimens and drug interactions with HCV treatment.

2 Infectious Diseases Clinical Hospital, Constanta, Romania

\*Address all correspondence to: cambrea.claudia@gmail.com

[1] Neumann AU, Lam NP, Dahari H, Gretch D R, Wiley T E, Layden T J, Perelson A S. Hepatitis C viral dynamics in vivo and the antiviral efficacy of interferon-alpha therapy. Science 1998; 282:103. DOI:10.1126/ science.282.5386.103

[2] Thein HH, Yi Q, Dore GJ, et al. Natural history of hepatitis C virus infection in HIV infected individuals and the impact of HIV in the era of highly active antiretroviral therapy: a meta-analysis. AIDS. 2008;22:1979-1991 DOI:10.1097/QAD.0b013e32830e6d51

[3] Netski DM, Mao Q, Ray SC, Klein RS. Genetic divergence of hepatitis C virus: the role of HIV-related immunosuppression. J Acquir Immune Defic Syndr 2008; 49:136. DOI:10.1097/ QAI.0b013e3181869a6f

[4] Lin W, Weinberg EM, Tai AW, et al. HIV increases HCV replication in a TGF-beta1-dependent manner. Gastroenterology 2008; 134:803. DOI:https://doi.org/10.1053/j. gastro.2008.01.005

[5] Khakoo SI, Thio CL, Martin MP, et al. HLA and NK cell inhibitory receptor genes in resolving hepatitis C virus infection. Science. 2004; 305:872- 874. DOI:10.1126/science.1097670

[6] Iannello A, Debbeche O, Samarani S, et al. Antiviral NK cell responses in HIV infection: viral strategies for evasion and lessons for immunotherapy and vaccination. J Leukoc Biol. 2008;84:27- 49 DOI: 10.1189/jlb.0907649

[7] Blackard JT, Kemmer N, Sherman KE. Extrahepatic replication of HCV: insights into clinical manifestations and biological consequences. Hepatology 2006; 44:15. DOI:10.1002/hep.21283

[8] Laskus T, Radkowski M, Piasek A, et al. Hepatitis C virus in lymphoid

cells of patients coinfected with human immunodeficiency virus type 1: evidence of active replication in monocytes/ macrophages and lymphocytes. J Infect Dis 2000; 181:442. DOI: 10.1086/315283

[9] Blackard JT, Smeaton L, Hiasa Y, et al. Detection of hepatitis C virus (HCV) in serum and peripheralblood mononuclear cells from HCVmonoinfected and HIV/HCV-coinfected persons. J Infect Dis 2005; 192:258. DOI: 10.1086/430949

[10] Minosse C, Calcaterra S, Abbate I, et al. Possible compartmentalization of hepatitis C viral replication in the genital tract of HIV-1-coinfected women. J Infect Dis 2006; 194:1529. DOI: 10.1086/508889

[11] Gaudieri S, Rauch A, Pfafferott K, et al. Hepatitis C virus drug resistance and immune-driven adaptations: relevance to new antiviral therapy. Hepatology 2009; 49:1069. DOI: 10.1002/hep.22773

[12] Kim AY, Chung RT. Coinfection with HIV-1 and HCV--a one-two punch. Gastroenterology 2009; 137:795. DOI: 10.1053/j.gastro.2009.06.040

[13] Platt L, Easterbrook P, Gower E, et al. Prevalence and burden of HCV co-infection in people living with HIV: a global systematic review and metaanalysis. Lancet Infect Dis 2016; 16:797. DOI: 10.1016/S1473-3099(15)00485-5

[14] Urbanus AT, van de Laar TJ, Stolte IG, et al. Hepatitis C virus infections among HIV-infected men who have sex with men: an expanding epidemic. AIDS 2009; 23:F1. DOI: 10.1097/QAD.0b013e32832e5631

[15] Tohme RA, Holmberg SD. Is sexual contact a major mode of hepatitis C virus transmission? Hepatology 2010; 52:1497. DOI: 10.1002/hep.23808

[16] Polis CB, Shah SN, Johnson KE, Gupta A. Impact of maternal HIV coinfection on the vertical transmission of hepatitis C virus: a meta-analysis. Clin Infect Dis 2007; 44:1123 DOI: 10.1086/512815

[17] Balagopal A, Ray SC, De Oca RM, et al. Kupffer cells are depleted with HIV immunodeficiency and partially recovered with antiretroviral immune reconstitution. AIDS 2009; 23:2397. DOI: 10.1097/QAD.0b013e3283324344

[18] Allison RD, Katsounas A, Koziol DE, et al. Association of interleukin-15-induced peripheral immune activation with hepatic stellate cell activation in persons coinfected with hepatitis C virus and HIV. J Infect Dis 2009; 200:619. DOI: 10.1086/600107

[19] Volkmann X, Fischer U, Bahr MJ, et al. Increased hepatotoxicity of tumor necrosis factor-related apoptosisinducing ligand in diseased human liver. Hepatology 2007; 46:1498. DOI: 10.1002/hep.21846

[20] Fierer DS, Dieterich DT, Fiel MI, et al. Rapid progression to decompensated cirrhosis, liver transplant, and death in HIV-infected men after primary hepatitis C virus infection. Clin Infect Dis 2013; 56:1038. DOI: 10.1093/cid/cis1206

[21] Benhamou Y, Bochet M, Di Martino V, et al. Liver fibrosis progression in human immunodeficiency virus and hepatitis C virus coinfected patients. The Multivirc Group. Hepatology 1999; 30:1054. DOI: 10.1002/hep.510300409

[22] Sulkowski MS, Mehta SH, Torbenson MS, et al. Rapid fibrosis progression among HIV/hepatitis C virus-co-infected adults. AIDS 2007; 21:2209. DOI: 10.1097/ QAD.0b013e3282f10de9

[23] Klein MB, Althoff KN, Jing Y, et al. Risk of End-Stage Liver Disease in

HIV-Viral Hepatitis Coinfected Persons in North America From the Early to Modern Antiretroviral Therapy Eras. Clin Infect Dis 2016; 63:1160. DOI: 10.1093/cid/ciw531

[24] Pascual-Pareja JF, Caminoa A, Larrauri C, et al. HAART is associated with lower hepatic necroinflammatory activity in HIV-hepatitis C viruscoinfected patients with CD4 cell count of more than 350 cells/microl at the time of liver biopsy. AIDS 2009; 23:971. DOI: 10.1097/qad.0b013e328329f994

[25] Thorpe J, Saeed S, Moodie EE, et al. Antiretroviral treatment interruption leads to progression of liver fibrosis in HIV-hepatitis C virus co-infection. AIDS 2011; 25:967. DOI: 10.1097/ QAD.0b013e3283455e4b

[26] Thein HH, Yi Q, Dore GJ, et al. Natural history of hepatitis C virus infection in HIV infected individuals and the impact of HIV in the era of highly active antiretroviral therapy: a metaanalysis. AIDS. 2008;22: 1979-1991. DOI: 10.1097/QAD.0b013e32830e6d51

[27] Bonfanti P, Valsecchi L, Parazzini F, et al. Incidence of adverse reactions in HIV patients treated with protease inhibitors: a cohort study. Coordinamento Italiano Studio Allergia e Infezione da HIV (CISAI) Group. J Acquir Immune Defic Syndr 2000; 23:236. DOI: 10.1097/00126334-200003010-00004

[28] den Brinker M, Wit FW, Wertheimvan Dillen PM, et al. Hepatitis B and C virus coinfection and the risk for hepatotoxicity of highly active antiretroviral therapy in HIV-1 infection. AIDS 2000; 14:2895 DOI: 10.1097/00002030-200012220-00011

[29] Benhamou Y, Di MV, Bochet M, et al. Factors affecting liver fibrosis in human immunodeficiency virus-and hepatitis C virus-coinfected patients: impact of protease inhibitor therapy.

**79**

*The Influence of Protease Inhibitors on the Evolution of Hepatitis C in Patients with HIV…*

therapy, interferon sensitivity, and virologic setpoint in human immunodeficiency virus/hepatitis C virus coinfected patients. Hepatology 2014; 60:477. DOI: 10.1002/hep.27158

[36] Braun DL, Hampel B, Kouyos R,

Grazoprevir-Elbasvir With or Without Ribavirin Guided by Genotypic Resistance Testing Among Human Immunodeficiency Virus/Hepatitis C Virus-coinfected Men Who Have Sex With Men. Clin Infect Dis 2019; 68:569.

[37] Wyles D, Bräu N, Kottilil S, et al. Sofosbuvir and Velpatasvir for the Treatment of Hepatitis C Virus in Patients Coinfected With Human Immunodeficiency Virus Type 1: An Open-Label, Phase 3 Study. Clin Infect Dis 2017; 65:6 DOI: 10.1093/cid/cix260

[38] Rockstroh JK, Lacombe K,

cid/ciy220

NEJMoa1501315

Viani RM, et al. Efficacy and Safety of Glecaprevir/Pibrentasvir in Patients Coinfected With Hepatitis C Virus and Human Immunodeficiency Virus Type 1: The EXPEDITION-2 Study. Clin Infect Dis 2018; 67:1010. DOI: 10.1093/

[39] Naggie S, Cooper C, Saag M, et al. Ledipasvir and Sofosbuvir for HCV in Patients Coinfected with HIV-1. N Engl J Med 2015; 373:705. DOI: 10.1056/

[40] Rockstroh JK, Orkin C, Viani RM, et al. Safety and Efficacy of Ombitasvir, Paritaprevir With Ritonavir ± Dasabuvir With or Without Ribavirin in Patients With Human Immunodeficiency Virus-1 and Hepatitis C Virus Genotype 1 or Genotype 4 Coinfection: TURQUOISE-I Part 2. Open Forum Infect Dis 2017; 4:ofx154. DOI: 10.1093/ofid/ofx154

[41] Basu P, Shah N, Aloysius M. Simeprevir and sofosbuvir with modified doses of ribavirin therapy on telaprevir-experience coinfeced

et al. High Cure Rates With

DOI: 10.1093/cid/ciy547

*DOI: http://dx.doi.org/10.5772/intechopen.96282*

Hepatology. 2001;34: 283-287. DOI:

[30] Sterling RK, Lissen E, Clumerk N, et al. Effect of protease inhibitors and non-nucleoside reverse transcriptase inhibitors on liver histology in HIV/ HCV co-infection. Analysis of patients enrolled in the AIDS Pegasys Ribabirin International Co-infection Trial (APRICOT); 12th Conference on Retroviruses and Opportunisitic Infections (CROI); Feb 22-25; Boston,

[31] Anderson KB, Guest JL, Rimland D. Hepatitis C virus coinfection increases mortality in HIV-infected patients in the highly active antiretroviral therapy era: data from the HIV Atlanta VA Cohort Study. Clin Infect Dis. 2004; 39:1507-

10.1053/jhep.2001.26517

MA. 2005. Abstract 951.

1513 DOI: 10.1086/425360

s0140-6736(00)03232-3

January 10, 2021).

on January 10, 2021).

[35] Balagopal A, Kandathil AJ, Higgins YH, et al. Antiretroviral

[32] Greub G, Ledergerber B,

Battegay M, et al. Clinical progression, survival, and immune recovery during antiretroviral therapy in patients with HIV-1 and hepatitis C virus coinfection: the Swiss HIV Cohort Study. Lancet. 2000;356:1800-1805 DOI: 10.1016/

[33] HCV Guidance: Recommendations for Testing, Managing, and Treating Hepatitis C. Joint panel from the American Association of the Study of Liver Diseases and the Infectious Diseases Society of America. http:// www.hcvguidelines.org/ (Accessed on

[34] Panel on Antiretroviral Guidelines for Adults and Adolescents. Guidelines for the use of antiretroviral agents in HIV-1-inf ected adults and adolescents. Department of Health and Human Services. Available at http://aidsinfo. nih.gov/contentfil es/lvguidelines/ AdultandAdolescentGL.pdf. (Accessed

*The Influence of Protease Inhibitors on the Evolution of Hepatitis C in Patients with HIV… DOI: http://dx.doi.org/10.5772/intechopen.96282*

Hepatology. 2001;34: 283-287. DOI: 10.1053/jhep.2001.26517

*Advances in Hepatology*

10.1086/512815

[16] Polis CB, Shah SN, Johnson KE, Gupta A. Impact of maternal HIV coinfection on the vertical transmission of hepatitis C virus: a meta-analysis. Clin Infect Dis 2007; 44:1123 DOI:

HIV-Viral Hepatitis Coinfected Persons in North America From the Early to Modern Antiretroviral Therapy Eras. Clin Infect Dis 2016; 63:1160. DOI:

[24] Pascual-Pareja JF, Caminoa A, Larrauri C, et al. HAART is associated with lower hepatic necroinflammatory activity in HIV-hepatitis C viruscoinfected patients with CD4 cell count of more than 350 cells/microl at the time of liver biopsy. AIDS 2009; 23:971. DOI:

10.1097/qad.0b013e328329f994

QAD.0b013e3283455e4b

[25] Thorpe J, Saeed S, Moodie EE, et al. Antiretroviral treatment interruption leads to progression of liver fibrosis in HIV-hepatitis C virus co-infection. AIDS 2011; 25:967. DOI: 10.1097/

[26] Thein HH, Yi Q, Dore GJ, et al. Natural history of hepatitis C virus infection in HIV infected individuals and the impact of HIV in the era of highly active antiretroviral therapy: a metaanalysis. AIDS. 2008;22: 1979-1991. DOI:

10.1097/QAD.0b013e32830e6d51

[28] den Brinker M, Wit FW, Wertheimvan Dillen PM, et al. Hepatitis B and C virus coinfection and the risk for hepatotoxicity of highly active antiretroviral therapy in HIV-1 infection. AIDS 2000; 14:2895 DOI: 10.1097/00002030-200012220-00011

[29] Benhamou Y, Di MV, Bochet M, et al. Factors affecting liver fibrosis in human immunodeficiency virus-and hepatitis C virus-coinfected patients: impact of protease inhibitor therapy.

[27] Bonfanti P, Valsecchi L, Parazzini F, et al. Incidence of adverse reactions in HIV patients treated with protease inhibitors: a cohort study. Coordinamento Italiano Studio Allergia e Infezione da HIV (CISAI) Group. J Acquir Immune Defic Syndr 2000; 23:236. DOI: 10.1097/00126334-200003010-00004

10.1093/cid/ciw531

[17] Balagopal A, Ray SC, De Oca RM, et al. Kupffer cells are depleted with HIV immunodeficiency and partially recovered with antiretroviral immune reconstitution. AIDS 2009; 23:2397. DOI: 10.1097/QAD.0b013e3283324344

[18] Allison RD, Katsounas A, Koziol DE, et al. Association of interleukin-15-induced peripheral immune activation with hepatic stellate cell activation in persons coinfected with hepatitis C virus and HIV. J Infect Dis 2009; 200:619. DOI: 10.1086/600107

[19] Volkmann X, Fischer U, Bahr MJ, et al. Increased hepatotoxicity of tumor necrosis factor-related apoptosisinducing ligand in diseased human liver. Hepatology 2007; 46:1498. DOI:

10.1002/hep.21846

[20] Fierer DS, Dieterich DT, Fiel MI, et al. Rapid progression to decompensated cirrhosis, liver transplant, and death in HIV-infected men after primary hepatitis C virus infection. Clin Infect Dis 2013; 56:1038.

DOI: 10.1093/cid/cis1206

[21] Benhamou Y, Bochet M, Di

[22] Sulkowski MS, Mehta SH, Torbenson MS, et al. Rapid fibrosis progression among HIV/hepatitis C virus-co-infected adults. AIDS 2007; 21:2209. DOI: 10.1097/ QAD.0b013e3282f10de9

Martino V, et al. Liver fibrosis progression in human immunodeficiency virus and hepatitis C virus coinfected patients. The Multivirc Group. Hepatology 1999; 30:1054. DOI: 10.1002/hep.510300409

[23] Klein MB, Althoff KN, Jing Y, et al. Risk of End-Stage Liver Disease in

**78**

[30] Sterling RK, Lissen E, Clumerk N, et al. Effect of protease inhibitors and non-nucleoside reverse transcriptase inhibitors on liver histology in HIV/ HCV co-infection. Analysis of patients enrolled in the AIDS Pegasys Ribabirin International Co-infection Trial (APRICOT); 12th Conference on Retroviruses and Opportunisitic Infections (CROI); Feb 22-25; Boston, MA. 2005. Abstract 951.

[31] Anderson KB, Guest JL, Rimland D. Hepatitis C virus coinfection increases mortality in HIV-infected patients in the highly active antiretroviral therapy era: data from the HIV Atlanta VA Cohort Study. Clin Infect Dis. 2004; 39:1507- 1513 DOI: 10.1086/425360

[32] Greub G, Ledergerber B, Battegay M, et al. Clinical progression, survival, and immune recovery during antiretroviral therapy in patients with HIV-1 and hepatitis C virus coinfection: the Swiss HIV Cohort Study. Lancet. 2000;356:1800-1805 DOI: 10.1016/ s0140-6736(00)03232-3

[33] HCV Guidance: Recommendations for Testing, Managing, and Treating Hepatitis C. Joint panel from the American Association of the Study of Liver Diseases and the Infectious Diseases Society of America. http:// www.hcvguidelines.org/ (Accessed on January 10, 2021).

[34] Panel on Antiretroviral Guidelines for Adults and Adolescents. Guidelines for the use of antiretroviral agents in HIV-1-inf ected adults and adolescents. Department of Health and Human Services. Available at http://aidsinfo. nih.gov/contentfil es/lvguidelines/ AdultandAdolescentGL.pdf. (Accessed on January 10, 2021).

[35] Balagopal A, Kandathil AJ, Higgins YH, et al. Antiretroviral therapy, interferon sensitivity, and virologic setpoint in human immunodeficiency virus/hepatitis C virus coinfected patients. Hepatology 2014; 60:477. DOI: 10.1002/hep.27158

[36] Braun DL, Hampel B, Kouyos R, et al. High Cure Rates With Grazoprevir-Elbasvir With or Without Ribavirin Guided by Genotypic Resistance Testing Among Human Immunodeficiency Virus/Hepatitis C Virus-coinfected Men Who Have Sex With Men. Clin Infect Dis 2019; 68:569. DOI: 10.1093/cid/ciy547

[37] Wyles D, Bräu N, Kottilil S, et al. Sofosbuvir and Velpatasvir for the Treatment of Hepatitis C Virus in Patients Coinfected With Human Immunodeficiency Virus Type 1: An Open-Label, Phase 3 Study. Clin Infect Dis 2017; 65:6 DOI: 10.1093/cid/cix260

[38] Rockstroh JK, Lacombe K, Viani RM, et al. Efficacy and Safety of Glecaprevir/Pibrentasvir in Patients Coinfected With Hepatitis C Virus and Human Immunodeficiency Virus Type 1: The EXPEDITION-2 Study. Clin Infect Dis 2018; 67:1010. DOI: 10.1093/ cid/ciy220

[39] Naggie S, Cooper C, Saag M, et al. Ledipasvir and Sofosbuvir for HCV in Patients Coinfected with HIV-1. N Engl J Med 2015; 373:705. DOI: 10.1056/ NEJMoa1501315

[40] Rockstroh JK, Orkin C, Viani RM, et al. Safety and Efficacy of Ombitasvir, Paritaprevir With Ritonavir ± Dasabuvir With or Without Ribavirin in Patients With Human Immunodeficiency Virus-1 and Hepatitis C Virus Genotype 1 or Genotype 4 Coinfection: TURQUOISE-I Part 2. Open Forum Infect Dis 2017; 4:ofx154. DOI: 10.1093/ofid/ofx154

[41] Basu P, Shah N, Aloysius M. Simeprevir and sofosbuvir with modified doses of ribavirin therapy on telaprevir-experience coinfeced

#### *Advances in Hepatology*

(with HIV) cirrhotics with chronic hepatitis C: A randomized open label clinical pilot study: STOP C. Presented a t the American Association for the Study of Liver Diseases Liver Meeting, Boston MA, November 7-11, 2014. Abstract #9 93.

[42] Dumea E, Cambrea CS, Petcu LC, Streinu Cercel A. Evaluation of liver diseases through transient elastography in patients with HIV infection. Archives of the Balkan Medical Union, 2013 vol 48, no 4:354-359.

[43] Dumea E, Streinu-Cercel A., Rugină S, Petcu L.C., Halichidis S., Cambrea S.C. Noninvasive assessments (APRI, FIB-4, transient elastography) of fibrosis in patients with HIV and HIV/HBV infection. Proceedings of the 12th Edition of the Scientific Days of the National Institute for Infectious Diseases "Prof Dr Matei Bals", BMC Infectious Diseases 2016, 16(Suppl 4): A52,

[44] Dumea E, Cambrea S.C, Ilie M.M, Petcu L.C, Streinu Cercel A. Evolution of patients coinfected with HIV and hepatitis B: virologic, immunologic, hepatic, regimens. Romanian Journal of Infectious Diseases 2013, vol XVI, no. 4: 218-226. DOI: 10.37897/RJID

[45] Dumitru I., Rugina S., Alexandrescu L, Dumitru E. Increased rates of spontaneous clearance of hepatitis C virus in patients infected with HIV. J Gastrointestin Liver Dis., December 2014, vol.23, no.4:461-462

**81**

Section 5

Liver Transplantation

Section 5
