OVERVIEW: What every clinician needs to know

Pathogen name and classification

The Hepatitis C virus (HCV) is a single stranded, positive sense, RNA virus belonging to the family Flaviviridae and is the only member of the genus Hepacivirus.

What patients should be treated?

The FDA approval of multiple direct-acting antiviral regimens for HCV has ushered in the interferon-free HCV treatment era. Pegylated interferon-based therapy is no longer indicated for any patients with HCV, save a very limited potential role in those with genotype 3 HCV, cirrhosis and prior treatment failure. In scenarios where treatment with pegylated interferon (PEG)-based therapies are still utilized, clinicians must keep the serious, potentially life-threatening side effects in mind when assessing the risks and benefits of therapy. HCV treatment efficacy is no longer a major consideration as direct acting antiviral (DAA) therapies offer high cure rates (>95% in most cases, though still slightly lower in treatment-experienced GT3 patients with cirrhosis).

A thorough evaluation of the patient’s readiness for therapy remains important before embarking on a course of therapy. A major shift has occurred in the wake of DAA therapies and current guidelines recommend treatment of all patients with HCV engaged in care unless faced with an extremely limited lifespan due to non-HCV related co-morbid conditions.

All IFN-free DAA genotype 1 treatment regimens drastically improve response rates and side-effects over prior IFN-based therapies. A careful pre-treatment evaluation remains critical to identify those with cirrhosis who require additional medical care and screening for HCC. Also, given the cost and limitations payers are placing on medication approvals in some locations, staging is likely to be required to obtain medication approval.

NOTE: In the remainder of the document HCV therapy or DAA therapy refers to interferon-free therapy unless specifically stated otherwise.

Treatment recommended

  • Treatment is recommended for all patients found to have chronic HCV infection

    Studies suggest even patients with minimal fibrosis are likely to benefit from HCV eradication (PMID 24316172).

    If treatment is postponed, fibrosis progression should be evaluated in the future.

Populations that deserve special attention in order to expedite treatment include:

  • Advanced fibrosis or cirrhosis (equivalent to Metavir stage 3 or 4)

    Patients with any current or prior evidence of decompensation (i.e. Childs-Pugh-Turcotte B or C) should only be treated by practitioners experienced in HCV therapy; preferably in association with a transplantation center.

  • Active/severe extra-hepatic manifestations of HCV disease (See section on extrahepatic manifestations)
  • Populations at risk for faster disease progression and poor outcomes (e.g. HIV-1 co-infection)
  • Patients diagnosed during acute infection

    Arbitrarily defined as within 6 months of initial infection

    Approaches to treatment with DAAs are generally the same as for chronic HCV infection.

Absolute contraindications to therapy with DAA regimens

  • There are no true absolute contraindications to HCV therapy

    Rare exception may be a documents severe allergic reaction

  • Patients with a very limited lifespan, arbitrarily defined as <12 months, due to non-HCV related comorbidities are generally not considered candidates for HCV therapy.

Factors which may delay start of HCV therapy

  • Uncontrolled psychiatric disease

    Medical management of psychiatric disease in consultation with a mental health professional

  • Ongoing substance abuse that interferes with compliance and follow-up

    Attempt to engage patients in care

    Medical management of addiction (e.g., Opiate Substitution Therapy)

    Ongoing substance use is NOT an absolute contraindication to therapy

    Careful consideration of patient’s ability to adhere to the HCV medical regimen required.

  • Active infections (opportunistic infections in those with HIV)
  • Decompensated liver disease

    Should be treated in conjunction with liver specialists

    Certain DAA medications are contraindicated in patients with decompensated liver disease

    HCV protease inhibitors should be avoided

There are now a number of DAA HCV treatment regimens approved; however treatment approaches are expected to continue to evolve.

Treatment for chronic HCV genotype 1 infection continues to evolve. Currently there are multiple HCV DAA regimens approved for treatment of GT1 HCV. All of these regimens offer outstanding efficacy (>90% success rates) and vastly improved side effect profiles compared to treatment with interferon-based regimens. Cure rates in HCV are defined by a sustained virologic response (SVR) measured at various time points after completion of therapy. The standard definition for cure is now SVR12- sustained virologic response (HCV RNA below the limit of quantification) 12 weeks after completion of therapy.

The relative merits of one regimen versus another surround:

  • the need for RBV
  • treatment duration (8 vs. 12 vs. 24 weeks)
  • pill burden and dosing schedules
  • drug interaction potential.

When used as recommended, efficacy differences between regimens are minimal. Ultimately, insurance coverage and access are often the major determinant of which regimen will be used in a given patient. Although access is improving- this remains the major impediment to treating diagnosed patients engaged in care.

HCV DAAs target several viral non-structural (NS) proteins including the NS3 protease, NS5A protein and the NS5B RNA polymerase. HCV NS3 and NS5B have well defined functions and DAAs act by inhibiting protease cleavage of the viral polyprotein or interfering with RNA replication by NS5B. NS5B polymerase inhibitors have two mechanisms of action- nucleotide polymerase inhibitors (e.g., sofosbuvir) are incorporated by the polymerase and then stop further elongation of the viral RNA (chain-termination). Non-nucleoside inhibitors of NS5B (e.g., dasabuvir) bind to allosteric sites on the polymerase and inhibit RNA replication indirectly.

While the NS5A protein does not have a defined enzymatic function it is critical for viral replication and assembly/release from cells. NS5A proteins exist as homodimers and NS5A inhibitors bind to these dimers, possibly disrupting its association with the viral replication complex.

NS3 protease inhibitors

Simeprevir (SMV, Olysio)

  • Stand-alone agent
  • Dose 150 mg PO QD
  • Used in combination with sofosbuvir
  • Should be avoided in decompensated cirrhosis (CPT B/C)

Paritaprevir (PTV, component of Viekira Pak)

  • Only in combination
  • Dose 100 mg PO QD (boosted with ritonavir)
  • Used in FDC with ombitasvir and separate dasabuvir
  • Should be avoided in decompensated cirrhosis (CPT B/C)

Grazoprevir (GZR, component of Zepatier)

  • Only in combination
  • Dose 100 mg PO QD
  • Used in FDC with elbasvir
  • Should be avoided in decompensated cirrhosis (CPT B/C)

NS5B RNA-dependent RNA polymerase inhibitors

Nucleotide inhibitors

Sofosbuvir (SOF, Sovaldi and component of Harvoni)

  • Stand-alone agent and in combination
  • Dose 400 mg PO QD
  • Used in FDC with ledipasvir; combined as stand alone agent other DAAs
  • Should be avoided in ESRD (eGFR <30 ml/min/1.73 m2)

Non-nucleoside inhibitors
Dasabuvir (DSV, component of Viekira Pak)

  • Only in combination
  • Dose 250 mg PO BID
  • Used in combination with the FDC PTV/r/ombitasvir
  • Should be avoided in decompensated cirrhosis (CPT B/C) due to combination with PTV

NS5A inhibitors

Ledipasvir (LDV, component of Harvoni)

  • Only in combination
  • Dose 90 mg PO QD
  • Used in FDC with sofosbuvir
  • Should be avoided in ESRD (eGFR <30 ml/min/1.73 m2) due to FDC with SOF

Daclatasvir (DCV, Daklinza)

  • Stand-alone agent
  • Dose 60 mg PO QD (dose can be adjusted 30-90 mg QD)
  • Used in combination with sofosbuvir

Ombitasvir (OBT, component of Viekira Pak)

  • Only in combination
  • Dose 25 mg PO QD
  • Used in FDC with PTV/r and additional DSV
  • Should be avoided in decompensated cirrhosis (CPT B/C) due to combination with PTV

Elbasvir (EBR, component of Zepatier)

  • Only in combination
  • Dose 50 mg PO QD
  • Used in FDC with grazoprevir
  • Should be avoided in decompensated cirrhosis (CPT B/C) due to combination with GZR

Velpatasvir (VEL, component of Epclusa)

  • Only in combination
  • Dose 100 mg PO QD
  • Used in FDC with sofosbuvir
  • Should be avoided in ESRD (eGFR <30 ml/min/1.73 m2) due to FDC with SOF
  • Improved resistance profile compared to other currently available NS5A inhibitors
Genotype 1 HCV

The following regimens are listed in alphabetical order. Regimens are noted to be alternatives in certain circumstances if features of the patient or regimen make it less attractive in a given setting but it may still be used safely and efficaciously if other issues such as medication access or cost make it the only option.

Preferred regimens:

  • Preferred regimen: Elbasvir 50 mg (EBR)/Grazoprevir 100 mg (GZR) FDC (ZepatierTM, Merck)
  • General regimen consideration and treatment approaches.

    NOTE: Regimen not recommend for those with CPT B or C cirrhosis.

    Drug interactions

    Both EBR and GZR are CYP3A substrates

    Coadministration with CYP3A inducers or inhibitors is not recommended

    See package insert for details

    Medications that should not be co-administered include:

    Ritonavir-boosted HIV PIs

    cobisistat

    Efavirenz or nevirapine

    St John’s wort

    Phenytoin or carbamazepine

    Rifamycins

    Use with caution with statins and in general use lowest dose possible.

This regimen combines a next-generation protease inhibitor (grazoprevir, improved non-genotype 1 activity and better resistance profile) with an NS5A inhibitor (elbasvir) in a FDC pill taken once daily. Data from phase 3 studies indicate excellent efficacy and tolerability; unique features of this regimen include phase 3 data in patients with end-stage renal disease and the recommendation for NS5A resistance testing in genotype 1a patients.

  • Treatment naïve patients, including 22% with cirrhosis

    12 weeks no RBV (n=316): 95% SVR12

    Genotype 1a: 92% SVR12

    1a with RAVs (n=19): 58% SVR12

    Genotype 1b: 99% SVR12

  • Treatment experienced patients, including 35% with cirrhosis

    12 weeks no RBV (n=105): 92% SVR12

    1a with baseline RAVs: 29% SVR12

    16 weeks plus RBV (n=106): 97% SVR12

    1a with baseline RAVs: 100% SVR12

  • End-stage renal disease patients

    12 weeks no RBV (n=116): 99% SVR12

  • HIV co-infection study, treatment naïve only, 16% with cirrhosis

    Allowed ARV: Raltegravir, rilpivirine, or dolutegravir plus nucleosides

    12 weeks no RBV (n=218): 96% SVR12

  • Dosing: 1 tablet PO QD

    Duration and use of RBV is determined by genotype 1 subtype (1a vs. 1b) and the presence of baseline NS5A resistance associated variants (RAVs)

    The presence of certain baseline NS5A RAVs are the best determinant of treatment response in patients with GT1a treated for 12 weeks no RBV

    SVR12 with RAVs: 89%

    SVR12 without RAVs: 99%

    Only a subset of NS5A RAVs impact EBR/GZR response

    Positions M28, Q30, L31M, and Y93

    Found in 5-10% of GT1a by population sequencing

    Commercially available HCV NS5A resistance testing

    LabCorp: CPT/test code: 87902/550705

    Quest: CPT/test code: 87902/92447

    Genotype 1a without baseline NS5A RAVs

    12 weeks no RBV

    Regardless of treatment experience or presence of cirrhosis

    This regimen is particularly attractive in TE, cirrhotic patients as RBV is not needed and only a 12 week duration

    Genotype 1a with baseline NS5A RAVs

    16 weeks plus RBV

    Regardless of treatment experience or presence of cirrhosis

    Standard weight-based RBV is recommended (1000/1200 mg)

    Genotype 1b (no RAV testing required)

    12 weeks no RBV

    Regardless of treatment experience or presence of cirrhosis

Preferred regimen: Ledipasvir/Sofosbuvir fixed dose combination (FDC, HarvoniTM, Gilead)

This regimen is composed of an NS5B nucleotide polymerase inhibitor (SOF) plus an NS5A inhibitor in a single FDC tablet. Data from phase 3 trials demonstrated high SVR12 rates in most populations and subgroups studied with excellent tolerability.

  • Treatment naïve patients, including 16% with cirrhosis

    12 weeks no RBV (n=214): 99% SVR12

    12 weeks plus RBV (n=217): 97% SVR12

    24 weeks no RBV (n=217): 98% SVR12

    24 weeks plus RBV (n=217): 99% SVR12

  • In a follow-up phase 3 study 8 weeks of treatment with or without RBV was compared to 12 weeks without RBV

    Treatment naïve, non-cirrhotic patients

    8 weeks no RBV (n= 215): 94% SVR12

    8 weeks plus RBV (n= 216): 93% SVR12

    12 weeks no RBV (n= 216): 95% SVR12

    Relapse rates were higher in 8 weeks arms and a post-hoc analysis identified the viral load cutoff of 6 million.

    Other studies have found female sex and IL28B CC status improved responses with 8 weeks

  • Treatment experienced patients, including 20% with cirrhosis

    12 weeks no RBV (n=109): 94% SVR12

    12 weeks plus RBV (n=111): 96% SVR12

    24 weeks no RBV (n=109): 99% SVR12

    24 weeks plus RBV (n=111): 99% SVR12

    All viral relapses were in the 12 week arms

  • A follow up randomized trial in treatment experienced patients with cirrhosis showed equivalent responses in this population with 12 weeks plus RBV and 24 weeks

    12 weeks plus RBV (n=77): 96% SVR12

    24 weeks no RBV (n=77): 97% SVR12

  • HIV co-infection, treatment naïve and experienced, 20% with cirrhosis

    Allowed ARVs included: efavirenz, raltegravir or rilpivirine.

    12 weeks no RBV (n=335): 96% SVR12

    10 viral relapses all in Black patients

    8/10 were on efavirenz based regimens

  • General regimen consideration and treatment approaches.

    Drug interactions

    Proton pump inhibitors: increase in gastric pH decreases the absorption of LDV

    Discontinue proton pump inhibitors (PPIs) unless absolutely medically necessary

    Dosing if co-administered:

    Maximum dose: omeprazole 20 mg QD (or equivalent)

    Taken at the same time as LDV

    H2 blockers

    Discontinue unless medically necessary

    Dosing if co-administered

    Maximum dose: famotidine 40 mg BID (or equivalent)

    Taken 12 hours apart from LDV

    Potent P-gp inducers

    Potential to decrease SOF exposure

    Avoid co-administration:

    Carbamazapine/Oxcarbamazapine

    Phenytoin

    Phenobarbital

    St. John’s Wart

    Rifampin (and other rifamycins)

    Tipranavir

    Statins

    Avoid rosuvastatin

    Co-administer with caution:

    Ritonavir-boosted HIV protease inhibitors when also given with TDF

    SOF and LDV increase tenofovir (TFV) levels when co-administered with tenofovir disoproxil fumarate (TDF)

    Ritonavir boosted HIV protease inhibitors increase LDV levels and are may also increase TFV levels.

    Consider alternative therapy for HCV if possible

    If co-administered, close monitoring for TDF-associated toxicity suggested

    Creatinine and U/A at week 2 and 4 of therapy and then monthly till complete

    See Harvoni package insert for complete list of drug interactions

    Metabolism and elimination

    Sofosbuvir

    primarily renal elimination in the form of inactive metabolite GS-33007

    Metabolite accumulates up to 20x in those with ESRD

    Not recommended in those with an eGFR <30 ml/min/1.73 m2

    Pgp substrate: levels decreased when coadministered with potent

    Not a CYP isoenzyme substrate

    Ledipasvir

    Pgp inhibitor and substrate

    Absorption optimal in low gastric pH

    Food effect: may be taken without regard to food intake

    Take with food if given with RBV

    Side effects and tolerability

    Bradycardia has been reported when LDV/SOF was given to patients on amiodarone (frequently in conjunction with a b-blocker)

    LDV/SOF is contraindicated in persons on amiodarone

  • Dosing 1 table PO QD (Ledipasvir 90 mg/Sofosbuvr 400 mg)

    Duration and use of RBV is dictated by cirrhosis status and prior treatment experience

    Important drug interaction (see section on drug interactions):

    Acid-reducing agents

    Potent P-gp inducers

    Treatment naïve (regardless of cirrhosis status)

    LDV/SOF 1 PO QD x 12 weeks

    Alternative for non-cirrhotic patients with HCV RNA <6 million IU/mL

    LDV/SOF 1 PO QD x 8 weeks

    NOT recommended in those with HIV co-infection

    NOTE: Viral load assessments are not equivalent across different platforms

    Cutoff based on Roche COBAS 2.0

    12 weeks should be used in patients with other unfavorable characteristic, examples include:

    Men with advanced fibrosis (e.g., Metavir F3)

    African-American males

    Extremely elevated BMI (e.g., >40)

    Treatment experienced without cirrhosis

    LDV/SOF 1 PO QD x 12 weeks

    Includes patients treated with an HCV PI + PEG/RBV

    Includes patients treated with SOF + PEG/RBV

    RBV should be added if no contraindications

    Treatment experienced with cirrhosis (CPT-A)

    Two equally efficacious options

    Includes patients treated with an HCV PI + PEG/RBV

    Includes patients treated with SOF + PEG/RBV

    LDV/SOF 1 PO QD x 12 weeks PLUS weight based RBV

    RBV 1000 mg (<75 kg), 1200 mg (>75 kg)

    This regimen is generally preferred given the significantly lower cost

    Contraindications to RBV include:

    Absolute:

    Hemoglobinopathies

    Other severe pre-existing anemia

    Relative:

    Coronary artery disease

    Prior intolerance

    Anemia due to RBV is significantly potentiated by interferon but not DAA therapies

    LDV/SOF 1 PO QD x 24 weeks

  • Preferred regimen: Paritaprevir/ritonavir/Ombitasvir 75 mg/50 mg/12.5 mg FDC 2 tablets QD plus Dasabuvir 250 mg BID (Viekira PakTM, AbbVie) +/- RBV.
  • General regimen consideration and treatment approaches.

    NOTE: Regimen contraindicated in those with CPT B or C cirrhosis

    NOTE: Use with caution in those with CPT A (compensated) cirrhosis

    Recent case reports of potential drug induced liver injury occurring early in therapy with this regimen have been reported.

    Drug interactions

    Given the use of ritonavir-boosting significant potential for drug interaction exit

    Consult package insert for full details.

    Oral contraceptives

    Ethinyl estradiol products

    Increased risk of ALT elevations

    Should not be co-administered with Viekira Pak.

This regimen combines a ritonavir-boosted NS3 PI (paritaprevir) plus an NS5A inhibitor (ombitasvir) in a FDC with a NS5B non-nucleoside inhibitor (dasabuvir). Differentiating factors for this regimen include a larger pill burden, components with BID dosing (DSV), and the need to always use RBV in patients with GT1a. In contrast for GT1b no RBV is needed and all patients can be treated with 12 weeks of therapy.

  • Treatment naïve patients, no cirrhosis

    12 weeks plus RBV (n=473): 96% SVR12

  • Treatment experienced patients, no cirrhosis

    12 weeks plus RBV (n=297): 96% SVR12

  • Treatment naïve and experienced patients with cirrhosis

    12 weeks plus RBV (n=208): 92% SVR12

    GT1a: 89% SVR12 (80% in 1a, prior null responders)

    24 weeks plus RBV (n=172): 96% SVR12

  • HIV co-infection study, treatment naïve and experienced, 16% with cirrhosis

    Allowed ARV: Atazanavir or raltegravir

    12 weeks plus RBV (n=31): 94% SVR12

    24 weeks plus RBV (n=32): 91% SVR12

    2 reinfections occurred after SVR4

  • Dosing: 2 PTV/r/OBV tablets PO QD plus 1 DSV tablet BID

    Duration and use of RBV is determined by genotype 1 subtype and the presence of cirrhosis

    Genotype 1a without cirrhosis (treatment naïve or experienced)

    NOTE: not recommend in those with prior HCV PI treatment

    12 weeks plus weight-based RBV

  • Genotype 1a with cirrhosis (treatment naïve or experienced)

    24 weeks plus RBV

    Regardless of treatment experience or presence of cirrhosis

    Weight-based RBV is recommended

  • Genotype 1b regardless of treatment history or cirrhosis status

    12 weeks no RBV

    Omission of RBV in cirrhotis patients treated for 12 weeks.

    SVR12 no RBV (n=60): 100% SVR12

  • Preferred regimen: Velpatasvir/Sofosbuvir fixed dose combination (FDC, EpclusaTM, Gilead)

This regimen is composed of an NS5B nucleotide polymerase inhibitor (SOF) plus an NS5A inhibitor (VEL) in a single FDC tablet.

  • It is the first FDC with pangenotypic activity and single duration (12 weeks) for all groups (naïve or experienced, cirrhosis or not) and genotypes (1-6).

    Prescribing information only recommends RBV in decompensated cirrhosis

    Guidelines endorse use of RBV in additional select populations

    GT3 cirrhosis with prior treatment experience

    GT3 treatment experienced with Y93H mutation

    GT3 treatment naïve with cirrhosis and Y93H mutation

Data from phase 3 trials demonstrated high SVR12 rates all populations and subgroups studied with excellent tolerability.

  • SVR12 rates are slightly lower in GT3 patients with either prior treatment or cirrhosis (~90%)
  • Treatment naïve or experienced patients GT1, 2, 4-6

    12 weeks no RBV is recommended for all subgroups (note exception for decompensated cirrhosis)

    SVR12 rates for select subgroups:

    Overall = 99% (618/624)

    GT1a = 98% (206/210)

    1a cirrhosis = 100% (49/49)

    GT1b = 99% (117/118)

    GT2 = 100% (104/104)

    GT4 = 100% (116/116)

    GT6 = 100% (41/41)

    <1% discontinued therapy due to an adverse event

    In a follow-up phase 3 of patients with GT2, VEL/SOF 12 weeks without RBV was compared to SOF/RBV 12 weeks

    VEL/SOF SVR12 = 99% (133/134)

    No virologic failures

    SOF/RBV SVR12 = 94% (124/132)

    6 virologic failures

    VEL/SOF was superior to SOF/RBV (p=0.02)

    Genotype 3-12 weeks of VEL/SOF is recommended

    RBV is added for select groups including:

    Treatment experienced patients with cirrhosis

    Treatment experienced patients with the NS5A Y93H RAV

    Treatment naïve patients with cirrhosis AND the NS5A Y93H RAV

    Dedicated phase 3 study in GT3, VEL/SOF 12 weeks without RBV was compared to SOF/RBV 24 weeks

    VEL/SOF SVR12 = 95%

    11 virologic failures

    SVR12 in key subgroups with VEL/SOF 12 weeks:

    Treatment experienced = 90% (64/71)

    Cirrhosis = 91% (73/80)

    SOF/RBV SVR12 = 80%

    38 virologic failures

    VEL/SOF was superior to SOF/RBV

    Treatment approaches with VEL/SOF in patients with HIV co-infection are the same as for those without HIV.

    VEL/SOF was studied in HIV/HCV patients in a phase 3 study:

    Allowed ARVs included:

    Ritonavir-boosted protease inhibitors

    Cobicistat-boosted integrase inhibitors

    ARVs not studied with VEL/SOF included:

    Efavirenz

    Nevirapine

    Etravirine

    Tipranavir

    General regimen consideration and treatment approaches.

    Drug interactions

    VEL is a substrate of CYP3A4, 2B6, and 2C8

    AVOID potent CYP inducers

    Efavirenz, Nevirapine, Etravirine

    Rifamycins

    Proton pump inhibitors: increase in gastric pH decreases the absorption of VEL

    Discontinue proton pump inhibitors (PPIs) unless absolutely medically necessary

    Dosing if co-administered:

    Maximum dose: omeprazole 20 mg QD (or equivalent)

    Take VEL/SOF with food 4 hours prior to PPI

    (NOTE: this adjustment is different than what is recommended for LDV/SOF)

    H2 blockers

    Discontinue unless medically necessary

    Dosing if co-administered

    Maximum dose: famotidine 40 mg BID (or equivalent)

    Taken 12 hours apart from LDV

    Potent P-gp inducers

    Potential to decrease SOF exposure

    Avoid co-administration:

    Carbamazapine/Oxcarbamazapine

    Phenytoin

    Phenobarbital

    St. John’s Wart

    Rifampin (and other rifamycins)

    Tipranavir

    Statins

    Rosuvastatin- dose should not exceed 10 mg

    Atorvastatin- monitor patients for adverse reactions related to increased atorvastatin exposure (e.g., myopathy)

    Co-administer with caution:

    Ritonavir-boosted HIV protease inhibitors when also given with TDF

    SOF and VEL increase tenofovir (TFV) levels when co-administered with tenofovir disoproxil fumarate (TDF)

    Ritonavir boosted HIV protease inhibitors increase VEL levels and are may also increase TFV levels.

    When co-administered, close monitoring for TDF-associated toxicity suggested

    Creatinine and U/A at week 2 and 4 of therapy and then monthly till complete

    See Epclusa package insert for complete list of drug interactions

    Metabolism and elimination

    Sofosbuvir

    primarily renal elimination in the form of inactive metabolite GS-33007

    Metabolite accumulates up to 20x in those with ESRD

    Not recommended in those with an eGFR <30 ml/min/1.73 m2

    Pgp substrate: levels decreased when coadministered with potent

    Not a CYP isoenzyme substrate

    Velpatasvir

    Substrate of CYP2B6, 2C8 and 3A4

    Pgp inhibitor and substrate

    BCRP substrate

    OATP1B1 and 1B3 substrate

    Absorption optimal in low gastric pH

    Food effect: may be taken without regard to food intake

    Take with food if given with RBV

    Side effects and tolerability

    Bradycardia has been reported with the related regimen LDV/SOF when given to patients on amiodarone (frequently in conjunction with a b-blocker)

    VEL/SOF (due to SOF component) is contraindicated in persons on amiodarone

    Dosing 1 table PO QD (Velpatasvir 100 mg/Sofosbuvr 400 mg)

    Duration is 12 weeks regardless of genotype or patient characteristics

    RBV use varies by genotype and patient characteristics

    Important drug interaction (see section on drug interactions):

    Acid-reducing agents

    Strong to moderate CYP inducer (3A4, 2B6, 2C8)

    Potent P-gp inducers

    Genotypes 1, 2, 4-6 (all patient groups)

    VEL/SOF 1 PO QD x 12 weeks

    Genotype 3 treatment naïve, no cirrhosis

    VEL/SOF 1 PO QD x 12 weeks

    Genotype 3 with treatment experienced with cirrhosis (naïve or experienced)

    12 weeks VEL/SOF plus weight-based RBV

    RBV 1000 mg (<75 kg), 1200 mg (>75 kg)

    Genotype 3, treatment naïve patients with cirrhosis

    Baseline NS5A resistance testing recommended

    No Y93H

    12 weeks VEL/SOF

    With Y93H

    12 weeks VEL/SOF plus weight-based RBV

    RBV 1000 mg (<75 kg), 1200 mg (>75 kg)

    Genotype 3, treatment experienced, non-cirrhotic patients

    Baseline NS5A resistance testing recommended

    No Y93H

    12 weeks VEL/SOF

    With Y93H

    12 weeks VEL/SOF plus weight-based RBV

    RBV 1000 mg (<75 kg), 1200 mg (>75 kg)

    Decompensated cirrhosis (all genotypes)

    12 weeks VEL/SOF plus weight-based RBV

    RBV 1000 mg (<75 kg), 1200 mg (>75 kg)

Two alternative regimens are listed below. While highly efficacious and well tolerated these regimens are significantly more expensive in the United States and are not likely to be approved by insurers unless unique situations exist requiring one of these regimens over those listed as preferred above.

  • Alternative regimen: Sofosbuvir (SovaldiTM, Gilead) plus Simeprevir (OlysioTM, Janssen Pharmaceuticals).

    NOTE: Simeprevir is not recommend in patients with CPT B or C cirrhosis.

    Drug interactions: SMV is a CYP3A4 substrate

    Do not co-administer with potent CYP3A4 inducers or inhibitors

    See package insert for details.

This regimen is unique in that it does not contain an NS5A inhibitor and thus may be uniquely situated for use in those with prior NS5A failure and resistance. Two phase 3 studies of SOF plus SMV have been completed. Data for use of 24 weeks are incomplete.

  • Treatment naïve and experienced patients, no cirrhosis (PMID: 26799692)

    12 weeks no RBV (n=155): 97% SVR12

    8 weeks no RBV (n=155): 83% SVR12

  • Treatment naïve and experienced patients, with cirrhosis (PMID: 26704148)

    12 weeks no RBV (n=103): 83% SVR12

    based on low SVR12, 24 weeks of treatment is recommended though not studied in phase 3.

  • Dosing: Administered as SOF (400 mg) 1 tablet PO QD plus SMV (150 mg) 1 tablet PO QD.

    Duration is guided by the presence of cirrhosis.

    RBV is recommended based in select settings based on incomplete data.

    Patients without cirrhosis (treatment naïve or experienced NO prior PI exposure)

    SOF plus SMV for 12 weeks

    SVR12 96%

    Patients with cirrhosis (No prior PI exposure)

    SOF plus SMV for 24 weeks

    Data with 12 weeks and indicate a suboptimal response

    SVR12

    SVR12 with 24 weeks of therapy:

    The role of RBV is unknown

    RBV can be considered in treatment experienced patients or those with baseline Q80K.

    Largely based on expert opinion

  • Alternative regimen: Sofosbuvir (SovaldiTM, Gilead) plus daclatasvir (DaklinzaTM, Bristol-Myers Squibb).

    Drug interactions: DCV is a CYP3A4 substrate

    Dose adjustment is required in the presence of CYP3A4 inducers (90 mg) or inhibitors (30 mg). Examples include:

    Efavirenz- dose DCV at 90 mg PO QD

    Atazanavir/ritonavir- dose DCV at 30 mg PO QD

    NOTE- the DCV dose is NOT decreased when used in combination with lopinavir/ritonavir or darunavir/ritonavir (DCV 60 mg PO QD)

    See package insert for details.

This regimen combines SOF with an NS5A inhibitor, daclatasvir, and is unique in that it is not a FDC and the dose of DCV can be adjusted to accommodate many drug-interactions. This aspect provides some flexibility compared to SOF/LDV. Perhaps more importantly, DCV is more pangenotypic with good activity against HCV GT2 and GT3 making this the preferred regimen for most patients with GT3 (see corresponding sections for treatment approaches).

  • Limited data are available for this regimen in GT1 with 12 weeks of therapy.
  • HIV co-infected treatment naïve and experienced patients, with and without cirrhosis

    Treatment naïve 12 weeks no RBV (n=83): 96% SVR12

    Treatment naïve 8 weeks no RBV (n=41): 76% SVR12

    Treatment experienced 12 weeks no RBV (n=44): 98% SVR12

  • Dosing: Administered as SOF (400 mg) 1 tablet PO QD plus DCV (60 mg) 1 tablet PO QD. Duration is guided by the presence of cirrhosis, though data are insufficient for definitive guidance.

    Patients without cirrhosis (treatment naïve or experienced including prior PI exposure)

    SOF plus DCV for 12 weeks

    Patients with cirrhosis

    SOF plus DCV for 24 weeks

    Data are limited in cirrhotic patients treated for either 12 or 24 weeks with this combination. A 24 week duration represents the conservative approach and is based on phase 2 study data.

    NOTE: A 12 week duration is recommended in the label

    The role of RBV is unknown

    RBV can be considered in treatment experienced patients or those with baseline NS5A resistance (if tested for).

    Largely based on expert opinion

    RBV should be added in those with CPT B or C cirrhosis

    Patients with CPT B and C cirrhosis should be treated in conjunction with a liver specialist/Hepatologist

    RBV dosed at 600 mg

    Increase as tolerated

Regimens no longer recommended for GT1:

  • Sofosbuvir plus RBV or SOF plus PEG/RBV are no longer recommended due to inferior efficacy and tolerability compared to current DAA regimens.
  • Simeprevir plus PEG/RBV is not recommended due to lower response rates and longer duration of PEG/RBV required (24-48 weeks)
  • Boceprevir and Telaprevir are no longer recommended due to poor tolerance, lower efficacy and prolonged durations of PEG-RBV exposure

    Similarly PEG/RBV alone is not recommended for GT1 patients.

General considerations:

  • Classification of prior treatment responses

    Relapser: undetectable HCV RNA at end of interferon-based therapy with subsequent recurrence

    Partial responder: greater than 2log10 HCV RNA decrease by week 12 on interferon but never undetectable

    Null responder: less than 2log10 HCV RNA decrease on interferon by week 12

    A less than 1log10 decrease at week 4 may also be used

  • Patient assistance programs:

    Sovaldi and Harvoni: www.mysupportpath.com

    Viekira Pak: www.viekira.com/proceed-support

    Zapatier: www.merckaccessprogram-zepatier.com

    Daklinza: www.daklinza.bmscustomerconnect.com/patient-support

    Simeprevir: www.Olysio.com

Current standard of care therapy for non-genotype 1 chronic hepatitis C infection differs depending on the specific viral genotype. Treatments for genotypes 2 and 3 are no longer lumped together as different regimens, durations and efficacy rates are seen. Genotypes 4, 5, and 6 are treated in a similar fashion to genotype 1, though not all genotype 1 regimens are appropriate for genotype 4-6 patients (see below).

In phase 3 studies cure rates of >95% are seen in treatment naïve patients with genotype 2 infection treated for 12 weeks. Cure rates drop modestly in treatment experienced GT2 patients, particularly those with cirrhosis, and thus treatment is extended in these patients. Sofosbuvir plus DCV is an option for GT2 patients who cannot take RBV though data are limited.

Genotype 3 infected patients have lower response rates with SOF/RBV, particularly in the setting of cirrhosis (SVR12 ~60%) thus this regimen is no longer recommended for GT3 patients. Sofosbuvir plus DCV has emerged as the current preferred regimen for patients with GT3 infection. Sofosbuvir plus PEG/RBV may be an option for some GT3 patients and offers high SVR12 rates, though patient and provider acceptance is limited.

Genotype 2

Regimen 1

  • Sofosbuvir 400 mg PO QD plus RBV 1000/1200 mg per day.

    SOF as single 400 mg tablet

    RBV divided BID by body weight

    >75 kg: 1200 mg RBV

    <75 kg: 1000 mg RBV

  • Duration 12 weeks

    Extension to 16 weeks in those with cirrhosis

    Further extension to 24 weeks in those with both treatment experience and cirrhosis may be considered

  • No response guided therapy and no established futility rules

Regimen 2- for patients with contraindications to RBV

  • Sofosbuvir 400 mg PO QD plus DCV 60mg PO QD.

    Drug interactions and other dosing consideration same as listed under genotype 1 treatment

    SOF as single 400 mg tablet

    DCV as a single 60 mg tablet

  • Duration 12 weeks

    Extension to 16-24 weeks can be considered in treatment experienced patients with cirrhosis

  • No response guided therapy and no established futility rules

Genotype 3

Sofosbuvir plus RBV is no longer recommended for treatment of GT3 patients.

Regimen 1

  • Sofosbuvir 400 mg PO QD plus DCV 60 mg PO QD.

    Drug interactions and other dosing consideration same as listed under genotype 1 treatment

    SOF as single 400 mg tablet

    DCV as a single 60 mg tablet

  • Treatment naïve or experienced without cirrhosis

    Duration 12 weeks

    SVR12: 96-97%

    Addition of RBV for those with NS5A RAV Y93H

  • Treatment naïve or experienced with cirrhosis

    Duration 16-24 weeks

    PLUS weight-based RBV

    SVR12: 88-89%

  • No response guided therapy and no established futility rules

Regimen 2

  • For treatment naïve and experienced patients with cirrhosis who can tolerate and are willing to take interferon

    SOF 400 mg QD plus PEG 180 mcg week plus RBV 1000/1200 mg QD

    SVR12: 93%

    Advantages

    Shorter treatment duration

    Improved efficacy over SOF/RBV for 24 weeks

    NOTE: Interferon therapy is associated with significant side effects and a risk of hepatic decompensation in those with cirrhosis. Treatment should only be undertaken by those experienced with interferon therapy, preferable in a transplant center.

Genotypes 4, 5, and 6

Genotypes 4

  • Regimens recommended for GT1 are generally effective in treating GT4.

    Key differences for each regimen in GT4 are noted.

    Drug interactions and other dosing considerations remain the same

  • SOF/LDV (Harvoni)

    1 tablet PO QD

    Treatment naïve with or without cirrhosis

    12 weeks

    Treatment experience with cirrhosis

    12 weeks plus weight-based RBV

    24 weeks without RBV

  • EBR/GZR (Zepatier)

    1 tablet PO QD

    NS5A RAV testing not commercially available for GT4

    Treatment duration is based on prior treatment history

    Treatment naïve or relapse

    12 weeks

    Partial or null responder

    16 weeks plus weight-based RBV

  • PTV/r/OBV plus weight-based RBV (NOTE Dasabuvir is omitted in GT4)

    2 tablets PO QD plus RBV divided BID

    12 weeks

    same duration regardless of cirrhosis or prior treatment

Genotypes 5 and 6

  • Extremely limited data exists
  • Should be treated as recommended for GT1 patients with SOF/LDV regimen

Historical section on use of interferon:

Specifics on the use and dosing of PEG and RBV:

  • Pegylated interferon alpha-2a (Pegasys®) contains a 40 kD branched PEG.

    Small volume of distribution (roughly the blood volume)

    Standard dose: 180 μg subcutaneously once a week

    No dose adjustment based on body weight

    Dose adjustment only for severe renal impairment or hemodialysis

    CrCl<30 mL/min or hemodialysis:135 mcg week

  • Pegylated interferon alpha-2b (Peg-intron®) contains a 12 kD linear PEG.

    Larger volume of distribution.

    Standard dose: 1.5 micrograms per kilogram subcutaneously once a week

    Dose adjustment is required for renal impairment.

    CrCl 30-50 mL/min: 25% dose reduction

    CrCl 10-29 mL/min: 50% dose reduction

    Hemodialysis: 50% dose reduction

  • Ribavirin is most commonly dosed using 200 mg tablets.

    Dosing recommendations vary by the HCV genotype and the patient’s body weight.

    Dose adjustment for renal impairment

    CrCl 30-50 mL/min: 200 mg QD alternating with 400 mg QD

    CrCl <30 mL/min or hemodialysis: 200 mg QD

    Consider further decrease to 200 mg QOD

    Titrate up to 200 mg QD as tolerated

Monitoring on therapy

Preferred DAA regimens

Minimal monitoring on therapy is required.

  • Week 4 on therapy

    CBC, basic metabolic panel (creatinine) and LFTs

    HCV RNA

    Primarily to ensure compliance

    Most patients should have low or undetectable HCV RNA levels

    No established futility rules

    Consider discontinuation if HCV RNA >1000 IU/mL

  • Patients with cirrhosis should have additional monitoring if on Viekira Pak or Zepatier

    LFTs at weeks 2 and 4.

    Any patients with ALT/AST > 10x ULN should immediately stop therapy

    Persistent ALT/AST elevations combined with elevated direct bilirubin, INR from baseline should also stop therapy.

  • Based on week 4 results additional monitoring may be needed.

    Repeat HCV RNA until undetectable or therapy stopped

  • Patients on SOF/LDV who are also on tenofovir disoproxil fumarate may require more intensive monitoring for renal dysfunction/tubular damage related to elevated tenofovir levels.

Monitoring for interferon and ribavirin is primarily of historical significance

Pegylated interferon and ribavirin are associated with multiple side effects, including but not limited to:

  • Hematologic: anemia, thrombocytopenia, and leukopenia/neutropenia
  • Psychiatric: depression, suicide, and mania
  • Endocrine: hypo or hyperthyroidism
  • Dermatologic: rash and pruritus

Additionally, therapy may precipitate a flare of hepatitis.

  • Rare progressive hepatitis with hepatic decompensation

    More common in those with advanced liver fibrosis

Given the availability of IFN-free treatment option only patients treated with IFN-containing regimens require intensive monitoring for side effects and laboratory abnormalities.

  • Toxicity laboratory assessments

    CBC

    Weeks 2 and 4, then approximately monthly

    Patients requiring dose reductions and/or growth factors need more frequent monitoring

    Chemistry and liver function tests

    Weeks 2 and 4, then approximately monthly

    TSH at baseline and every 12 weeks on therapy

HCV treatment approaches and responses with interferon-freee DAA therapies are similar in those co-infected with HIV with several important caveats.

Treatment of genotype 1 HCV

  • Drug interactions are the major consideration and specific to each regimen

    Refer to package inserts

    The University of Liverpool drug interaction website is a good resource

    http://www.hep-druginteractions.org

  • A recent review summarized the drug interactions with HCV PI and many classes of medications (Kiser Clinical Infectious Diseases 2016 in press).

The following is a list of HIV drugs to avoid with specific DAAs:

Simeprevir

  • All HIV PIs
  • Efavirenz
  • Cobicistat

Paritaprevir/ritonavir/ombitasvir plus dasabuvir

  • Rilpivirine
  • Efavirenz or nevirapine
  • Lopinavir/ritonavir
  • Caution with darunavir/ritonavir
  • Cobicistat

Sofosbuvir

  • Tipranavir

Ledipasvir/sofosbuvir

  • Tipranavir
  • Cobicistat
  • Caution with ritonavir-boosted HIV PIs in patients also on tenofovir disoproxil fumarate

Elbasvir/Grazoprevir

  • All HIV PIs
  • Efavirenz or nevirapine
  • Cobicistat

Daclatasvir

  • Can be used with all ART but dose adjustment may be required
  • 30 mg with Atazanavir/ritonavir or cobicistat
  • 90 mg with efavirenz or nevirapine
Side-effect management ()

Side effects frequently encountered during interferon-based HCV therapy include flu-like symptoms (fatigue, fever, myalgia), cytopenias, depression, thyroid abnormalities, and weight loss. Effective management of treatment-induced side effects is key to optimizing the dose and duration of antiviral therapy received.

Interferon contributes to all cytopenias through its suppressive effect on hematopoiesis. Anemia is primarily related to ribavirin induced hemolysis, which is exacerbated by both interferon and HCV protease inhibitors. Neutropenia and thrombocytopenia are primarily side effects of interferon therapy.

  • Anemia

    Development of anemia on therapy is associated with improved SVR rates.

    Ribavirin dose reduction is the primary method for dealing with anemia, particularly in the setting of HCV PI use.

    Specific recommendations vary

    Ribavirin dose reduction does not adversely impact treatment outcomes for PI based therapy

    Hgb less than 10 g/dL

    Decrease RBV by 200-400 mg per day

    Magnitude of decrease will depend on rapidity and amount of the drop

    More aggressive dose reductions (50%) should be undertaken in those with cardiovascular disease.

    Consider earlier dose reduction in this population (Hgb <12 g/dL).

    Hgb less than 8.5 g/dL

    Hold ribavirin

    Caution: patients being treated with an HCV PI must also stop the PI.

    Ribavirin therapy may be restarted once hemoglobin has recovered (>10-11 g/dL).

    Start at 600 mg; slow titration (200 mg every 2 weeks) up as tolerated

    Recombinant erythropoietin (epoetin alfa) may be used in place of or in addition to dose RBV dose reduction.

    Careful consideration of the risk/benefits must be considered.

    A meta-analysis examining the impact of epoetin alpha suggested improved adherence and SVR rates.

    The value of adding erythropoietin to PI-based therapy is not established.

    Side effects include

    Hypertension

    Cardiovascular events (stroke, myocardial infarction)

    Thrombosis

    Pure red cell aplasia

    Adequate iron stores should be verified prior to initiating therapy.

    Hgb less than 10 g/dL

    40,000 units sc q week: complete blood count (CBC) and blood pressure minimum of every 2 weeks; dose may be increase if poor response (<1 g/dL rise) after 4 weeks

    Hold for Hgb greater than 12 g/dL: restart at 25-50% of original dose for Hgb less than 11 g/dL

  • Neutropenia

    ANC less than 750 per mm3

    Occurs in 10-15% of patients with PEG/RBV.

    20% with boceprevir or telaprevir

    ANC less than 500 per mm3

    4-5% with PEG/RBV

    7% with boceprevir

    Increased rates of infections attributed to treatment induced neutropenia have not been described.

    Interferon therapy itself does predispose to bacterial infections.

    Primary management is interferon dose reduction.

    ANC less than 750 per mm3

    25% dose reduction in pegylated interferon

    ANC less than 500 per mm3

    50% dose reduction

    Repeat CBC in 1-2 weeks: low threshold to discontinue interferon if ANC still <500/mm3; consider GCSF

    GCSF (filgrastim) administration may be considered

    Not of proven benefit

    Consider in patients whose HCV RNA is not yet undetectable (dose reductions may have negative impact on SVR) and inadequate response to dose reduction alone (to avoid therapy discontinuation)

    300 mcg SC q week: Goal ANC greater than 1000/mm3; CBC should be checked before next injection (nadir); frequency can be increased to achieve goal ANC

    Side effects

    Common: bony pain

    Severe/rare: splenic rupture, ARDS, alveolar hemorrhage

    Precipitation of sickle cell crisis

    Allergic reactions and Sweet’s syndrome (neutrophilic dermatosis)

  • Thrombocytopenia

    Less than 50,000

    25-50% dose reduction in pegylated interferon

    Magnitude related to rapidity and magnitude of reduction

    Repeat CBC in 1-2 weeks

    Less than 25,000

    Discontinue interferon

  • Constitutional symptoms

    Best managed by adjustments in dosing schedule and premedication

    Pegylated interferon injections at bedtime

    Premedication with ibuprofen or acetaminophen

    Total dose of acetaminophen must be closely monitored in cirrhotics.

    Less than 2000 mg per day

  • Depression/central nervous system

    Central nervous system side effects, including depression, irritability, and difficulty with concentration, are extremely common during interferon-based HCV therapy.

    Major depressive disorder report in about 30% of patients.

    Depression may be severe, and suicide has been reported.

    Patients with a history of severe depression (hospitalization, suicide attempts) or poorly controlled depression should be managed in conjunction with a psychiatrist.

    Patients with a history of depression not currently on treatment

    Initiation of an selective serotonin reuptake inhibitor (SSRI) at least 2 weeks prior to therapy

    Clinical trials suggest that pre-treatment can decrease the severity of depression during treatment (may improve medication adherence and improve SVR rates).

    The majority of clinical trial data is with citalopram and paroxetine.

    Citalopram 20 mg PO QD

    Low potential for significant drug-drug interactions

    Start at 10 mg PO QD in cirrhotics

    Escitalopram is also unlikely to significantly impact HCV PI pharmacokinetics.

    10 mg PO QD

    Dose dependent QT prolongation with both citalopram and escitalopram

    Do not co-administer with other drugs which can impact QT

    Do not co-administer CYP 2C19 inhibitors (e.g., efavirenz)

    Paroxetine 20 mg PO QD

    Other SSRIs may be used

    Patients with bipolar disorder or other psychotic disorders may be treated if psychiatric disease is stable.

    Should be managed in conjunction with a psychiatrist or other mental health professional in all cases

Treatment failure and resistance
  • Treatment failure (non-response, breakthrough, or relapse) with pegylated interferon and ribavirin is not associated with specific viral resistance mutations.

    PEG/RBV ineffectiveness is associated with a number of viral and patient characteristics, including:

    HCV genotype 1 or 4

    HCV Viral load (>800,000 IU/L)

    Chronic infection (vs acute)

    IL28B genotype CT or TT (rs12979860)

    Advanced stages of liver disease (cirrhosis)

    Retreatment of patient who previously failed PEG/RBV is extremely effective using current DAA regimens

  • Specific resistance mutations within the protease gene are found after failure with PI containing regimens.

    In vitro these mutations are associated with decreased antiviral activity of the PI.

    Resistance mutations for telaprevir, boceprevir, simeprevir and paritaprevir overlap, and cross-resistance is expected.

    Patients failing a PI-containing regimen should not be re-treated with the another PI-based regimen.

    Grazoprevir has a higher barrier to resistance and slightly different resistance profile compared the above mentioned PIs

    GZR retains activity against the R155K variant in GT1a

    Cross resistance with other PIs does occur at positions 156 and 168

    Limited data with GZR/EBR suggest efficacy in patients previously failing PEG/RBV + PI

    Given excellent results with non-PI containing regimens in re-treating PEG/RBV + PI treatment failures EBR/GZR is not recommended in those failing a prior PI containing regimen.

  • NS5A resistance is frequently selected after failing an NS5A inhibitor containing regimen

    NS5A resistance persists for >2 years

    NS5A resistance also appears to impact re-treatment responses.

  • Patients who have failed an interferon-free DAA regimen should have resistance testing done including:

    NS3 protease and NS5A resistance genotyping

  • Optimal re-treatment approaches are not well studied

    Re-treatment should be undertaken in consultation with an HCV expert

Treatment of acute HCV

The majority of persons infected with HCV go on to develop chronic infection (70-80%). However, because of its mild and often non-specific symptoms, acute HCV infection is difficult to diagnose. Given the excellent responses now seen with treatment using DAAs in chronic HCV infection, there is no benefit in treating early to improve response rates. A benefit in terms of prevention of future transmission (treatment as prevention) may be realized, however, this remains largely theoretical at this point.

Limited data suggest that treatment during acute infection may not have the same impact on responses with DAAs as was seen with interferon-based therapies.

  • Acute HCV diagnosis

    HCV RNA is the preferred diagnostic test for acute HCV infection and monitoring

    Positive 1-2 weeks after infection

    Requires a high index of suspicion or known high-risk exposure

    Monitored to determine spontaneous clearance

    The majority who clear do so within 12 weeks

    A 2 log decrease in HCV RNA over first 4 weeks of infection is associated with spontaneous clearance.

    A negative HCV RNA should be repeated 3-6 months later (relapse has been reported especially in those with HIV).

    If HCV RNA remains detectable at or after 12 weeks, treatment should be considered.

    HCV antibody is not reliable for diagnosis of acute HCV infection.

    HCV antibody generally appears within 2-3 months.

    Antibody appearance can be delayed out to 1 year, particularly in HIV co-infected patients.

    Appearance of HCV antibody is not associated with clearance.

    Hepatic transaminases (ALT, AST)

    Elevated in nearly all case of acute HCV infection

    Greater than 10 times the upper limit of normal is frequent during acute infection

    New or dramatic elevation should trigger an evaluation for acute HCV

  • Acute HCV treatment

    Treatment of acute HCV infection should be strongly considered in patients who do not clear HCV infection spontaneously within 12 weeks of the estimated date of infection.

    Efficacy is no longer a major consideration to treat during the acute stage

    Patients with acute HCV infection may be more likely to engage in risk behaviors and are a reservoir for ongoing forward transmission of HCV

    Prompt treatment of HCV may prevent further transmissions

    Treatment approaches are the same as for chronic HCV

    Sufficient data are not yet available to truncate DAA therapy in the acute setting.

How do patients contract this infection, and how do I prevent spread to other patients?

HCV Epidemiology
  • Prevalence

    Worldwide: 170-200 million persons infected

    United States: 3-4 million with chronic infection (1.3%)

    As high as 5-7 million accounting for high risk populations (2%)

    Highest prevalence: Egypt 15-20%

    Presumed largely due to iatrogenic transmission/unsafe injection practices

    Lowest prevalence: Scandinavia/Northern Europe less than 1%

  • Incidence

    An alarming trend of increased HCV incidence has been seen in United States over the last 3 years

    The increase has been most dramatic in young age groups

    20-29 and 30-39 years old

    Outbreaks of acute HCV are also increasingly seen in non-urban areas

    Estimated 30,000 new (acute) infections in 2013 (cdc.gov, viral hepatitis surveillance 2013)

    Increasing incidence presumed due to

    Increased injection drug use

    Transition from prescription opiates to injection drug use

    Much publicized outbreak of HIV and HCV in rural Indiana.

    >90% in that outbreak with HCV infection

    The problem does not appear to be isolated to the Midwest

    Multiple states have seen a >200% increase in incident HCV cases from 2006-2012

    States include:

    New York

    California

    Florida

    Illinois

HCV transmission

The routes via which the exposure occurs differ based on the risk factors for a given population and influence the frequency with which infection is established following exposure.

The primary mode is percutaneous exposure to blood or blood-products containing HCV RNA.

  • Intravenous drug use is the primary means of HCV transmission in the United States.

    HCV can survive for more than 1 week in blood in syringes.

    Implements used in drug preparation may also play a role in transmission (cotton swabs, etc.).

  • Infection by transfusion is exceedingly rare in the United States (<1 in a million)

    Predominate mode of transmission in the United States prior to 1991

    Sequential implementation of HCV antibody and nucleic acid testing screening essentially eliminated transmission via transfusion.

    Less than 0.5 in a million per unit transfused

    Remains an issue in the developing world

  • Medical procedures/other injections

    Sporadic case reports in the United States

    Improper use of multi-use injectable medication vials

    Poor sterilization technique

    A major source of transmission in the developing world

  • Healthcare-associated needle-stick exposures

    1-3% transmission rate

    No post-exposure prophylaxis available

  • Vertical transmission

    Occurs in roughly 5% of infants born to mother with detectable HCV RNA

    15-20% transmission rate if the mother is HIV infected

    Diagnosis in infants

    HCV antibody may remain positive for 12-18 months because of placental transfer of maternal IgG antibody.

    Diagnosis relies on HCV RNA with testing at:

    2-6 months of age

    Repeated 3-6 months later or after 18 months old

    Spontaneous clearance may occur

    Prevention

    Cesarean section is not recommended to prevent HCV transmission

    Exception if mother is also HIV-positive

    Breast feeding is not known to transmit HCV

    Invasive scalp monitoring should be avoided

  • Sexual transmission

HCV is NOT readily transmitted by sexual contact under most circumstances. However, sexual transmission of HCV serves as a major source of incident HCV infection in HIV-positive men who have sex with men (MSM).

  • Exceedingly rare for heterosexual couples in long-term relationships

    No transmission was observed over 10 years in a study of heterosexual couples.

    No specific recommendation for measures to prevent HCV sexual transmission in this population

    HIV-positive partner seems to increase the rate of transmission of HCV in heterosexual couples.

    3% HCV infection rate in long-term female partners of HCV/HIV+ men

  • Sexual transmission in HIV-positive MSM

    Increasing over the last decade

    Has been described in major urban centers of Europe and North America

    Incidence estimate in the United States from 1996 to 2008 (5.1 cases per 1000 patient-years)

    Risk factors

    Unprotected receptive anal intercourse

    Group sex

    Traumatic sexual practices (fisting, use of sex toys)

    Non-injection drug use (methamphetamines, GHB)

    Concomitant STIs

    Majority (60-75%) have few or no symptoms

    Dramatic increases in HCV incidence in HIV negative MSM have not been noted, although the HCV prevalence in this population is higher than the general population.

    Annual HCV antibody screening should be performed in high-risk HIV-positive populations.

    MSM with high-risk sexual practices

    Injection drug user

    Hepatic transaminases (ALT, AST) semi-annually

    Inexpensive and readily available

    May facilitate earlier diagnosis

    Diagnosis and treatment during acute infection results in improved cure rates.

Infection control issues
  • Standard universal precautions should be followed.

    No special personal protective equipment or precautions are required.

Prevention
  • No HCV vaccine is currently available.
  • Prophylactic therapy is not recommended.

    A significant proportion of acutely infected persons may clear HCV on their own (20-30%).

    Clearance rates appear to be higher with symptomatic acute infection (50%).

    Clearance rate depends on a number of factors, including:

    IL28B genotype: CC genotype resulted in a greater than 50% clearance rate

    Age: younger age at infection favors clearance

    Sex: females clear more frequently

    Co-morbid conditions (e.g., HIV): spontaneous clearance rates of roughly 10%

    Patients who have not cleared within 12 weeks of infection should be considered for therapy. (See chapter on Treatment of Acute HCV Infection.)

What host factors protect against this infection?

Establishment of infection with HCV is largely determined by the type and intensity of exposure.

  • Host factors are not known to be involved with the risk of developing initial infection.
  • Host factors play a significant role in:

    Outcome of acute infection (resolution vs. chronic)

    Response to antiviral therapy

  • Immune system factors that protect from chronic HCV infection

    Neutralizing antibodies have a limited role in controlling or resolving HCV infection.

    Reinfection is possible following treatment induced HCV clearance.

    Immunoglobulin preparations are not effective as post-exposure prophylaxis.

    Strong and sustained multi-specific T-cell responses are associated with clearance.

    Single nucleotide polymorphisms near the IL28B (interferon lambda) gene

    rs12979860 C/C genotype (vs C/T or T/T): three times more likely to clear

    Human leukocyte antigens

    HLA B27

    Natural Killer cell immunoglobulin-like receptors

    KIR2DL3/HLA-C1

Histopathology of HCV infection
  • HCV diagnosis is based on antibody and viral RNA detection.
  • Histopathology is used for grading the severity of liver disease and fibrosis staging.

    Stage of liver disease is the best prognostic factor for future complications.

  • Typical HCV histopathology

    Portal inflammation with lymphocytic infiltrates (nodular)

    Interface hepatitis

    Lymphocytic infiltration at the border between portal tracts and parenchyma

    Hepatocyte apoptosis/dropout

    Lobular hepatitis

    Steatosis is typically present.

    Macrovesicular

    More pronounced with genotype 3 infection

    Should be differentiated from concomitant steatohepatitis

    Mild bile duct damage

    Fibrosis (if present)

    Starts in portal tracts

    Progression with septa

    Bridging fibrosis- connection of septa

    Cirrhosis: bridging fibrosis with regenerative nodules

    Additional (often unsuspected) diagnoses may be found in up to 20% of biopsies.

    Three most common additional diagnoses

    Steatosis +/- steatohepatitis

    Hemosiderosis

    Hepatocellular carcinoma

What are the clinical manifestations of infection with this organism?

HCV infection is now the leading cause of mortality from chronic viral infections in the United States, recently surpassing HIV infection.

Liver-related manifestations
  • Chronic hepatitis

    Develops in 60-80% of those infected

    Those more likely to clear acute infection include:

    Women

    IL28CC genotype

    Young age at infection

    Most are asymptomatic until end-stage liver disease develops.

    Chronic fatigue may be noted.

    Transaminitis on routine laboratory studies

    ALT/AST elevations

    ALT/AST may be normal in up to 1/3.

    Does not preclude the development of progressive fibrosis

    Progressive hepatic fibrosis

  • End Stage Liver Disease

    Clinical manifestation of cirrhosis on liver histology

    Develops over the course of 20-40 years

    Estimated to develop in 20% of those chronically infected

    Accelerated by alcohol abuse and HIV co-infection

    Progression is NOT associated with the level of HCV viremia or viral genotype.

    May be clinically silent until decompensation occurs

    Signs of decompensation

    Jaundice

    Ascites

    Esophageal varices with bleeding

    Coagulopathy (elevated INR)

    Encephalopathy

  • Hepatocellular Carcinoma

    Incidence of 1-4% per year in those with cirrhosis

    Chronic HCV is most common cause in the United States.

    Screening for hepatocellular carcinoma

    Initiated once cirrhosis is diagnosed or suspected

    Abdominal ultrasound every 6-12 months is preferred in guidelines

    CT (Quad-phase) or MRI are likely more sensitive

    Not validated as screening tools

    Cost and radiation exposure are concerns

    Serum alpha-feto protein is not recommended as a screening tool.

    Use remains common in clinical practice.

    Role in evaluation of suspicious lesions identified on imaging

  • Extra-hepatic manifestations

    Cryoglobulinemia- type II and III mixed cryoglobulinemia

    40-50% of persons with chronic HCV will have circulating cryoglobulins

    Majority will not have clinical symptoms

    Up to 95% of patients with clinically symptomatic cryoglobulinemia will have chronic HCV

    Clinical symptoms

    Vasculitis

    Palpable purpura

    Nonspecific symptoms such as fatigue and arthralgias

    Neuropathy

    Renal disease: membranoproliferative glomerulonephritis

Patients presenting with symptoms suggestive of or diagnosed with mixed cryoglobulinemia should be screened for HCV.

Clinically active cryoglobulinemia due to chronic HCV is an indication for HCV treatment.

NOTE: Patients presenting with severe clinical manifestations due to cryoglobulinemia (renal failure/vasculitis) will require treatment to control disease prior to HCV therapy.

Rituximab plus pegylated interferon and ribavirin has shown promising early trial results.

  • Porphyria cutanea tarda

    Photosensitivity and skin lesions (bullae and vesicles) in sun exposed areas

    Roughly 50% of sporadic cases will have evidence of HCV infection

    Treatment of HCV may result in improvement.

  • Diabetes mellitus

    Strong epidemiologic association between HCV infection and the development of diabetes

    Three time more likely to develop diabetes mellitus than those without HCV

    Improvements in insulin sensitivity have been described with effective HCV therapy.

  • Other extra-hepatic manifestations/complications

    B-cell lymphoproliferative disorders

    B-cell Non-Hodgkin’s lymphoma

    Central nervous system effects

    Fatigue, depression, and reduced health-related quality of life

    Cognitive-impairment

  • Sicca syndrome

    Oral and ocular dryness

    Sialadenitis does not appear to improve with effective HCV therapy.

  • Vitiligo
  • Lichen planus

How should I identify the organism?

The Hepatitis C virus is a positive-strand RNA virus with the primary site of replication being hepatocytes. The entire virus life cycle takes place within the cellular cytoplasm. Unlike retroviruses, such as HIV-1, there is no DNA intermediate or integrated form of HCV from which to create a viral archive.

Testing for the virus relies on two techniques: detection of antibody to the virus and direct detection of viral RNA.

HCV serologic testing

Testing for the presence of HCV antibodies in blood is the first step is assessing a patient for possible HCV infection.

  • HCV antibody (AB) detection via enzyme immunoassay (EIA) is the standard screening test

    Greater than 98% sensitivity for third-generation assays

    Detectable about 2 months after infection

    False negatives during early acute infection and severely immunosuppressed

    False positives if low risk populations (low pre-test probability) are screened

    DOES NOT indicate active infection (HCV viremia)

    Appearance of HCV AB may be delayed in immunosuppressed persons.

    Mean time to detectability about 6 months in HIV co-infected

    Reports of antibody appearance delayed out to greater than 1 year

    HCV RIBA (recombinant immunoblot) is a confirmatory test that detects antibody to specific HCV antigens.

    Historically used to confirm a positive HCV EIA (e.g., rule out a false-positive EIA in low risk persons)

    Limited role now with widely available HCV RNA assays

    DOES NOT indicate active infection

HCV ribonucleic acid detection
  • HCV RNA detection

    Detection of HCV RNA via RT-PCR (or other similar nucleic acid amplification techniques)

    Mainstay of diagnosis for chronic HCV infection

    Diagnosis of acute infection prior to appearance of antibody

    positive within 1-2 weeks of infection

    A number of commercial quantitative RT-PCR assays are available.

    Critical to following viral response during therapy

    The same assay should be used for serial measurements

HCV is difficult to grow in cell culture, and cell culture is not used clinically for virus isolation/diagnosis.

Liver disease staging

The clinical course of chronic HCV infection is highly variable with some persons developing significant fibrosis within a few decades, whereas others may never develop clinically significant fibrosis or complication related to HCV. Accurate disease staging remains a key component of the management of HCV infection from both a treatment decision standpoint, as well as for monitoring of complications related to cirrhosis, such as HCC.

  • Individual routine blood tests (e.g., ALT, bilirubin, INR or platelets) cannot accurately stage liver disease.
  • Indices composed of several common clinical laboratory parameters:

    Simple and can be calculated from readily available patient data

    Can identify advanced fibrosis/cirrhosis reasonably well.

    APRI: AUROC 0.88-0.94 for identifying advanced fibrosis/cirrhosis

    FIB-4: AUROC 0.85-0.91 for identifying advanced fibrosis/cirrhosis

    FORNS: AUROC 0.81-0.86 for excluding significant fibrosis/cirrhosis

    May eliminate the need for biopsy in a subset of patients

  • Specialized assays

    FibroSure (also called FibroTest in Europe)

    Combines routine and specialized blood tests in a proprietary algorithm

    Haptoglobin, total bilirubin, alpha-2 macroglobulin, apolipoprotein A1, and GGT

    AUROC 0.85 (0.82-0.87) for distinguishing F0/1 versus F2-4 (meta-analysis)

    Decreased AUROC (about 0.65) for distinguishing adjacent stage of fibrosis

    20-25% discordance with biopsy

    Roughly one-half due to biopsy failure (inadequate sample)

    Better than biopsy at predicting HCV-related complication and death over 5 years

    Limitations

    Situations that significantly limit the diagnostic accuracy

    Gilbert syndrome

    Medications which raise bilirubin (e.g., atazanavir)

    Acute inflammation (alters haptoglobin)

    Increased cost

    Requires specialized testing (compared to APRI or FIB-4)

    Imaging techniques

    Ultrasound

    Routine ultrasound is not a reliable measure of hepatic fibrosis.

    Portal venous pressures/flows may improve sensitivity

    Transient Elastography (FibroScan™)

    Specialized ultrasound technique for assessing fibrosis

    FDA-approved in May 2013

    AUROC 0.94 for discriminating between cirrhosis and mild fibrosis

    Sensitivity 85% for detecting greater than or equal to F2 fibrosis

    Limitations

    Cannot discriminate between acute inflammation and fibrosis

    Is not yet widely available

    Liver biopsy: the accepted standard for staging of liver disease (see histopathology section)

    Advantages

    Direct assessment of:

    Fibrosis and inflammation

    Iron stores

    Steatosis

    Diagnosis or suggestion of other liver pathology

    Steatohepatitis

    Alcoholic hepatitis

    Drug-induced injury

    Auto-immune hepatitis

    Limitations

    Invasive

    Pain is common but generally mild to moderate

    Complication rate: 1 in 1,000 to 10,000

    Bleeding most common

    Mortality: less than or equal to 1 in 10,000

    Primarily due to hemorrhage

    Sampling error or inadequate sampling

    Paired biopsies from left and right lobe

    33% with greater than or equal to 1 stage difference in fibrosis

    Ideally16-gauge needle or wider

    Minimum criteria for an adequate biopsy

    Greater than 2cm total length

    11 portal tracts

    Inter-observer variability

    Approaches

    Ultrasound guided, percutaneous

    Trans-jugular

    Reserved for those with contraindications to percutaneous biopsy

    Morbid obesity

    Ascites

    Coagulopathy

    Biopsy assessment- grading/staging systems

    Grade: assessment of disease activity and inflammation

    Stage: evaluation of the extent of fibrosis

    Common grading systems

    Simple systems: largely descriptive

    Metavir

    Activity: A0-A3

    Fibrosis: F0-F4

    F4 equals cirrhosis

    Other examples include IASL and Batts-Ludwig

    Complex numerical scoring systems

    Histology Activity Index (HAI or Knodell)

    Modified HAI (mHAI or Ishak)

    Grade: numerical score from 0-18 with discrete categories

    Stage: 0-6

    5/6 equals incomplete/complete cirrhosis

How does this organism cause disease?

Liver inflammation and fibrosis

Liver disease progression is highly variable and non-linear in chronic HCV infection. It is estimated that, after 30 years, 20% of patients will have had progressive fibrosis to the point of cirrhosis. Following the development of cirrhosis clinical events, such as the development of ascites, encephalopathy, variceal bleeding, and hepatocellular carcinoma, occur leading to appreciable morbidity and mortality. Antiviral therapy can cure HCV and is associated with not only improved clinical outcomes, but reversal of liver fibrosis.

  • HCV is not directly cytopathic for hepatocytes.
  • Liver disease with progressive fibrosis is related to chronic inflammation and the immune response.

    Progression of liver disease is NOT correlated with the level of viremia.

    Viral genotype is not a strong predictor of disease progression.

    Genotype 3 HCV is associated with steatosis, which may accelerate disease progression.

    Non-viral factors associated with more rapid liver disease progression include:

    Male gender

    Alcohol use

    Duration of infection

Establishment of chronic infection
  • HCV has evolved a number of strategies leading to efficient establishment of chronic infection.

    Viral characteristics favoring chronic infection

    Error prone viral RNA polymerase allows rapid viral mutation

    Mutation in hypervariable region 1 (HVR 1) of the second envelope protein

    Escape from neutralizing antibody

    Subversion of innate immune responses and interferon signaling by viral proteins

    Viral NS3 protease

    Inhibition of TLR3 signaling (sensing of ssRNA)

    Inhibition of RIG-I signaling (sensing of dsRNA)

    Other viral proteins, including core, E2, and NS5A, have been associated with subverting antiviral immune responses

    Up regulation of Programmed Death receptor-1 (PD-1) on HCV-specific CD8 cells

    Increase in non-functional cytotoxic T cells (immune exhaustion)

    Direct cell-to-cell spread of virus

    Avoidance of neutralizing antibody

WHAT’S THE EVIDENCE for specific management and treatment recommendations?

Ghany, MG, Nelson, Dr, Strader, DB. “An update on treatment of genotype 1 chronic hepatitis C virus infection: 2011 practice guideline by the American Association for the Study of Liver Diseases”. Hepatology. vol. 54. 2011. pp. 1433-1444.

“EASL Clinical Practice Guidelines: management of hepatitis C virus infection”. Hepatology. vol. 61. 2014. pp. 373-396.

Thomas, DL, Bartlett, JG, Peters, MG. “Provisional guidance on the use of hepatitis C virus protease inhibitors for treatment of hepatitis C in HIV-infected persons”. Clin Infect Dis. vol. 54. 2012. pp. 979-983.

Kiser, JJ, Burton, JR, Anderson, PL, Everson, GT. “Review and management of drug interactions with boceprevir and telaprevir”. Hepatology. vol. 55. 2012. pp. 1620-1628.

“European AIDS Treatment Network (NEAT) Acute Hepatitis C Infection Consensus Panel. Acute hepatitis C in HIV-infected individuals: recommendations from the European AIDS Treatment Network (NEAT) consensus conference”. AIDS. vol. 25. 2011. pp. 399-409.

Bruix, J, Sherman, M. “American Association for the Study of Liver Diseases. Management of hepatocellular carcinoma: an update”. Hepatology. vol. 55. 2011. pp. 1020-1022.

Jacobson, IM, McHutchison, JG, Dusheiko, G, Di Bisceglia, AM, Reddy, KR. “Telaprevir for previously untreated chronic hepatitis C virus infection”. N Engl J Med. vol. 364. 2011. pp. 2405-2516.

Poordad, F, McCone, J, Bacon, BR, Bruno, S, Manns, MP. “Boceprevir for untreated chronic HCV genotype 1 infection”. N Engl J Med. vol. 364. 2011. pp. 1195-1206.

Zeuzem, S, Andreone, P, Pol, S, Lawitz, E. “Telaprevir for retreatment of HCV infection”. N Engl J Med. vol. 364. 2011. pp. 2417-2428.

Bacon, BR, Gordon, SC, Lawitz, E, Marcellin, P, Vierling, JM, Zeuzem, S, Poordad, F, Goodman, ZD, Sings, HL, Boparai, N, Burroughs, M, Brass, CA, Albrecht, JK, Esteban, R. “HCV RESPOND-2 Investigators. Boceprevir for previously treated chronic HCV genotype 1 infection”. N Engl J Med. vol. 364. 2011. pp. 1207-1217.

Alavian, Sm, Tabatabaei, SV, Behnavas, B. “Impact of erythropoietin on sustained virological response to peginterferon and ribavirin therapy for HCV infection: a systematic review and meta-analysis”. J Viral Hepat. vol. 19. 2012. pp. 88-93.

Yu, JW, Sun, LJ, Zhao, YH, Kang, P, Yan, BZ. “The study of relationship between neutropenia and infection during treatment with peginterferon α and ribavirin for chronic hepatitis C”. Eur J Gastroenterol Hepatol. vol. 23. 2011. pp. 1192-9.

Galvao-de Almeida, A, Guindalini, C, Batista-Neves, S. “Can antidepressants prevent interferon-alpha-induced depression? A review of the literature”. Gen Hosp Psychiatry. vol. 32. 2010. pp. 401-405.

Jaeckel, E, Cornberg, M, Wedemeyer, H, Santantonio, T. “Treatment of acute hepatitis C with interferon alfa-2b”. N Engl J Med. vol. 345. 2001. pp. 1452-1457.

Blackard, JT, Shata, MT, Shire, NJ, Sherman, KE. “Acute hepatitis C virus infection: a chronic problem”. Hepatology. vol. 47. 2008. pp. 321-331.

Alter, MJ. “Epidemiology of hepatitis C virus infection”. World J Gastroenterol. vol. 13. 2007. pp. 2436-2441.

Armstrong, GL, Wasley, A, Simard, EP, McQuillan, GM, Kuhnert, WL, Alter, MJ. “The prevalence of hepatitis C virus infection in the United States, 1999 through 2002”. Ann Intern Med. vol. 144. 2006. pp. 705-714.

Chak, E, Talal, AH, Sherman, KE, Schiff, ER, Saab, S. “Hepatitis C virus infection in USA: an estimate of true prevalence”. Liver Int. vol. 31. 2011. pp. 1090-1101.

Dwyre, DM, Fernando, LP, Holland, PV. “Hepatitis B hepatitis C and HIV transfusion-transmitted infections in the 21st century”. Vox Sang. vol. 100. 2011. pp. 92-98.

Sulkowski, MS, Ray, SC, Thomas, DL. “Needlestick transmission of hepatitis C”. JAMA. vol. 287. 2002. pp. 2406-2413.

Roberts, EA, Yeung, L. “Maternal-infant transmission of hepatitis C virus infection”. Hepatology. vol. 36. 2002. pp. S106-113.

Vandelli, C, Renzo, F, Romano, L, Tisminetzky, S. “Lack of evidence of sexual transmission of hepatitis C among monogamous couples: results of a 10-year prospective follow-up study”. Am J Gastroenterol. vol. 99. 2004. pp. 855-859.

Van de Laar, TJ, Matthews, GV, Prins, M, Danta, M. “Acute hepatitis C in HIV-infected men who have sex with men: an emerging sexually transmitted infection”. AIDS. vol. 24. 2010. pp. 1799-1812.

Thomas, DL, Thio, CL, Martin, MP, Qi, Y. “Genetic variation in IL28B and spontaneous clearance of hepatitis C virus”. Nature. vol. 461. 2009. pp. 798-801.

Nair, V, Fischer, SE, Adeyi, OA. “Non-viral-related pathologic findings in liver needle biopsy specimens from patients with chronic viral hepatitis”. Am J Clin Pathol. vol. 133. 2010. pp. 127-132.

Ly, KN, Xing, J, Klevens, RM, Jiles, RB. “The increasing burden of mortality from viral hepatitis in the United States between 1999 and 2007”. Ann Intern Med. vol. 156. 2012. pp. 271-278.

Jacobson, IM, Cacoub, P, Dal Maso, L, Harrison, SA, Younossi, ZM. “Manifestations of chronic hepatitis C virus infection beyond the liver”. Clin Gastroenterol Hepatol. vol. 8. 2010. pp. 1017-1029.

Thomson, EC, Nastouli, E, Main, J, Karayiannis, P. “Delayed anti-HCV antibody response in HIV-positive men acutely infected with HCV”. AIDS. vol. 23. 2009. pp. 89-93.

Wai, CT, Greenson, JK, Fontana, RJ, Kalbfleisch, JD. “A simple noninvasive index can predict both significant fibrosis and cirrhosis in patients with chronic hepatitis C”. Hepatology. vol. 38. 2003. pp. 518-526.

Vallet-Pichard, A, Mallet, V, Nalpoas, B, Verkarre, V. “FIB-4: an inexpensive and accurate marker of fibrosis in HCV infection. comparison with liver biopsy and fibrotest”. Hepatology. vol. 56. 2007. pp. 32-36.

Forns, X, Ampurdanè, S, Llovet, JM, Aponte, J. “Identification of chronic hepatitis C patients without hepatic fibrosis by a simple predictive model”. Hepatology. vol. 36. 2002. pp. 986-992.

Imbert-Bismut, F, Fatziu, V, Pieroni, L, Charlotte, F. “Biochemical markers of liver fibrosis in patients with hepatitis C virus infection: a prospective study”. Lancet. vol. 357. 2001. pp. 1069-1075.

Poynard, T, Morra, R, Halfon, P, Castera, L. “Meta-analyses of FibroTest diagnostic value in chronic liver disease”. BMC Gastroenterol. vol. 7. 2007. pp. 40

Ngo, Y, Munteanu, M, Messous, D, Charlotte, F. “A prospective analysis of the prognostic value of biomarkers (FibroTest) in patients with chronic hepatitis C”. Clin Chem. vol. 52. 2006. pp. 1887-1896.

Coco, B, Oliveri, F, Maina, AM, Ciccorossi, P. “Transient elastography: a new surrogate marker of liver fibrosis influenced by major changes of transaminases”. J Viral Hepat. vol. 14. 2007. pp. 360-369.

Gale, M, Foy, EM. “Evasion of intracellular host defence by hepatitis C virus”. Nature. vol. 436. 2005. pp. 939-945.