Viekira Pak-RBV: Indications, Dosage, Precautions, Adverse Effects
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Viekira Pak-RBV - Product Information

Manufacture: AbbVie
Country: Australia
Condition: Hepatitis C, Hepatitis C, Chronic (Hepatitis C)
Class: Antiviral combinations
Form: Tablets
Ingredients: Paritaprevir/Ritonavir/Ombitasvir, Copovidone, Tocofersolan, Propylene Glycol Monolaurate, Sorbitan Monolaurate, Silicon Dioxide, Sodium Stearylfumarate, Polyvinyl Alcohol, Macrogol 3350, Purified Talc, Titanium Dioxide, Iron Oxide Red, Dasabuvir, Microcrystalline Cellulose, Lactose, Croscarmellose Sodium, Colloidal Anhydrous Silica, Magnesium Stearate, Polyethylene Macrogol 3350, Iron Oxide Yellow, Red and Black, Povidone, Magnesium Stearate, Purified Water, Indigo Carmine Aluminium Lake or Brilliant Blue Fcf Aluminium Lake

Name of the Medicine

VIEKIRA PAK-RBV is a composite pack containing paritaprevir/ritonavir/ombitasvir 75/50/12.5 mg tablets, dasabuvir 250 mg tablets and 200 mg, 400 mg or 600 mg ribavirin tablets.

Refer to DOSAGE AND ADMINISTRATION for populations requiring ribavirin.

Chemical Structure and Description of each Active Pharmaceutical Ingredient

Paritaprevir

Paritaprevir drug substance is manufactured as a dihydrate, however is dehydrated during the drug product manufacturing process and is amorphous and anhydrous in the final product. Paritaprevir dihydrate is chemically designated (2R,6S,12Z,13aS,14aR,16aS)-N- (Cyclopropylsulfonyl)-6-{[(5-methylpyrazin-2-yl)carbonyl]amino}-5,16-dioxo-2-(phenanthridin-6-yloxy)-1,2,3,6,7,8,9,10,11,13a,14,15,16,16atetradecahydrocyclopropa[e]pyrrolo[1,2-a][1,4] diazacyclopentadecine-14a(5H)-carboxamide dihydrate. The molecular formula is C40H43N7O7S•2H2O (dihydrate) and the molecular weight for the drug substance is 801.91 (dihydrate). Paritaprevir dihydrate has the following structural formula:


CAS Number: 1456607-71-8

Paritaprevir dihydrate is a white to off-white powder with very low water solubility. Paritaprevir dihydrate has a pKa of 4.6 at 25°C.

Ritonavir

Ritonavir is chemically designated as [5S-(5R*,8R*,10R*,11R*)]10-Hydroxy-2-methyl-5-(1-methyethyl)-1-[2-(1-methylethyl)-4-thiazolyl]-3,6-dioxo-8,11-bis(phenylmehyl)-2,4,7,12-tetraazatridecan-13-oic acid,5-thiazolylmethyl ester. The molecular formula is C37H48N6O5S2 and the molecular weight is 720.95. Ritonavir has the following structural formula:


CAS Number: 155213-67-5

Ritonavir is a white to light tan powder practically insoluble in water and freely soluble in methanol and ethanol. Ritonavir has a pKa of 2.8.

Ombitasvir

Ombitasvir drug substance is manufactured as a hydrate, however is dehydrated during the drug product manufacturing process and is amorphous and anhydrous in the final product. Ombitasvir hydrate is chemically designated as Dimethyl ([(2S,5S)-1-(4-tert-butylphenyl) pyrrolidine-2,5-diyl]bis{benzene-4,1-diylcarbamoyl(2S)pyrrolidine-2,1-diyl[(2S)-3-methyl-1-oxobutane-1,2-diyl]})biscarbamate hydrate. The molecular formula is C50H67N7O8 • 4.5H2O (hydrate) and the molecular weight for the drug substance is 975.20 (hydrate). Ombitasvir hydrate has the following structural formula:


CAS Number: 1456607-70-7

Ombitasvir hydrate is a white to light pink powder, and is practically insoluble in aqueous buffers but is soluble in ethanol. Ombitasvir hydrate has a pKa of 2.5 at 25°C.

Dasabuvir

Dasabuvir drug substance is manufactured as a sodium salt monohydrate, and is present in the product as the sodium salt monohydrate. Dasabuvir sodium monohydrate is chemically designated as Sodium 3-(3-tert-butyl-4-methoxy-5-{6-[(methylsulfonyl)amino]naphthalen-2-yl}phenyl)-2,6-dioxo-3,6-dihydro-2H-pyrimidin-1-ide hydrate (1:1:1).The molecular formula is C26H26N3O5S•Na•H2O (salt, hydrate) and the molecular weight of the drug substance is 533.57 (salt, hydrate). Dasabuvir hydrate has the following molecular structure:


CAS Number: 1456607-55-8

Dasabuvir sodium monohydrate is a white to off-white to pink powder, slightly soluble in water and very slightly soluble in methanol and isopropyl alcohol. The pKa values of dasabuvir are 8.2 (pK1) and 9.2 (pK2).

Ribavirin

Ribavirin is chemically defined as 1-β-D-ribofuranosyl-1H-1,2,4-triazole-3-carboxamide. The molecular formula of ribavirin is C8H12N4O5 and the molecular weight is 244.2. Ribavirin has the following molecular structure:


CAS Number: 36791-04-5

Ribavirin is a white to off-white powder. It is freely soluble in water and slightly soluble in anhydrous alcohol. Ribavirin has a pKa of 12.25.

Description

Paritaprevir, ritonavir, and ombitasvir are co-formulated as film-coated immediate release tablets. The tablets also contain copovidone, tocofersolan, propylene glycol monolaurate, sorbitan monolaurate, silicon dioxide, sodium stearyl fumarate and Opadry II pink 85F140088 (polyvinyl alcohol, titanium dioxide, macrogol, purified talc, and iron oxide red) The tablets do not contain gluten. The strength for the fixed dose combination tablet is 75 mg paritaprevir/50 mg ritonavir/12.5 mg ombitasvir.

Dasabuvir is formulated as a 250 mg film-coated, immediate release tablet containing microcrystalline cellulose, lactose, copovidone, croscarmellose sodium, colloidal anhydrous silica, magnesium stearate, and Opadry II Beige 85F97497 (polyvinyl alcohol, titanium dioxide, macrogol, purified talc, and iron oxide yellow, iron oxide red and iron oxide black.). The tablets do not contain gluten.

Ribavirin is available as a blue-coloured (shade depending on strength), oblong, film-coated tablet for oral administration. Each tablet contains 200 mg, 400 mg, or 600 mg of ribavirin and the following inactive ingredients: microcrystalline cellulose, lactose, croscarmellose sodium, povidone, magnesium stearate, and purified water. The coating of the 200 mg tablet contains Opadry Blue 85F90614 (polyvinyl alcohol, titanium dioxide, macrogol, purified talc, and indigo carmine lake). The coating of the 400 mg tablet contains Opadry II blue 85F90553 (polyvinyl alcohol, titanium dioxide, macrogol, purified talc, and indigo carmine aluminium lake) and 600 mg tablet contains Opadry II blue 85F90623 (polyvinyl alcohol, titanium dioxide, macrogol, purified talc, and brilliant blue aluminium lake).

Pharmacology

Pharmacodynamics

Pharmacotherapeutic group: Direct-acting antiviral, ATC code: J05AX66; J05AB04

Mechanism of Action

VIEKIRA PAK–RBV combines ribavirin with three direct-acting hepatitis C virus antiviral agents with distinct mechanisms of action and non-overlapping resistance profiles to target HCV at multiple steps in the viral lifecycle.

Paritaprevir is an inhibitor of HCV NS3/4A protease which is necessary for the proteolytic cleavage of the HCV encoded polyproteins (into mature forms of the NS3, NS4A, NS4B, NS5A, and NS5B proteins) and is essential for viral replication.

Ritonavir is not active against HCV. Ritonavir is a pharmacokinetic enhancer that increases peak and trough plasma drug concentrations of paritaprevir and overall drug exposure (i.e. area under the curve).

Ombitasvir is an inhibitor of HCV NS5A which is necessary for viral replication.

Dasabuvir is a non-nucleoside inhibitor of the HCV RNA-dependent RNA polymerase encoded by the NS5B gene.

Ribavirin is a synthetic nucleoside analog that shows in vitro activity against some RNA and DNA viruses. The mechanism by which ribavirin exerts its effects against HCV is unknown.

Oral formulations of ribavirin monotherapy have been investigated as therapy for chronic hepatitis C in several clinical trials. Results of these investigations showed that ribavirin monotherapy had no effect on eliminating hepatitis virus (HCV-RNA) or improving hepatic histology after 6 to 12 months of therapy and 6 months of follow-up. Monotherapy with ribavirin is not recommended.

Activity in Cell Culture and/or Biochemical Studies

Paritaprevir

In a biochemical assay, paritaprevir inhibited the proteolytic activity of the recombinant HCV genotype 1a and 1b NS3/4A protease enzymes with IC50 values of 0.18 nM and 0.43 nM, respectively. The EC50 of paritaprevir against genotype 1a-H77 and 1b-Con1 strains in the HCV replicon cell culture assay was 1.0 and 0.21 nM, respectively. The activity of paritaprevir was attenuated 24- to 27-fold in the presence of 40% human plasma. The mean EC50 of paritaprevir against replicons containing NS3 from a panel of treatment-naïve genotype 1a and 1b isolates in the HCV replicon cell culture assay was 0.86 nM (range 0.43 to 1.87 nM; n = 11) and 0.06 nM (range 0.03 to 0.09 nM; n = 9), respectively. Paritaprevir had an EC50 value of 5.3 nM against the 2a-JFH-1 replicon cell line, and EC50 values of 19, 0.09, and 0.68 nM against replicon cell lines containing NS3 from a single isolate each of genotype 3a, 4a, and 6a, respectively. In a biochemical assay, paritaprevir inhibited the activity of NS3/4A enzymes from single isolates of genotypes 2a, 2b, 3a, and 4a with IC50 values of 2.4, 6.3, 14.5, and 0.16 nM, respectively.

Ritonavir did not exhibit a direct antiviral effect on the replication of HCV subgenomic replicons, and the presence of ritonavir did not affect the in vitro antiviral activity of paritaprevir.

Ombitasvir

In replicon cell culture assays, ombitasvir has EC50 values of 14.1 pM and 5.0 pM against HCV genotypes 1a-H77 and 1b-Con1, respectively. The activity of ombitasvir was attenuated 11- to 13-fold in the presence of 40% human plasma. The mean EC50 of ombitasvir against replicons containing NS5A from a panel of treatment-naïve genotype 1a and 1b isolates in the HCV replicon cell culture assay was 0.66 pM (range 0.35 to 0.88 pM; n = 11) and 1.0 pM (range 0.74 to 1.5 pM; n = 11), respectively. Ombitasvir has EC50 values of 12, 4.3, 19, 1.7, 3.2, and 366 pM against replicon cell lines constructed with NS5A from single isolates representing genotypes 2a, 2b, 3a, 4a, 5a, and 6a, respectively. Negligible anti-viral activity against genotypes 1a-H77 and 1b-Con1 was noted by the human major metabolites of ombitasvir, M29 and M36 in the HCV replicon assay; M29 and M36 do not contribute to antiviral activity of ombitasvir.

Dasabuvir

In a biochemical assay, dasabuvir inhibited the polymerase activity of the recombinant HCV genotype 1a and 1b HCV NS5B enzymes with IC50 values of 2.8 nM and 10.7 nM, respectively. The EC50 of dasabuvir against genotype 1a-H77 and 1b-Con1 strains in HCV replicon cell culture assays was 7.7 and 1.8 nM, respectively. The replicon activity of dasabuvir was attenuated 12- to 13-fold in the presence of 40% human plasma. The mean EC50 of dasabuvir against replicons containing NS5B from a panel of treatment-naïve genotype 1a and 1b isolates in the HCV replicon cell culture assay was 0.77 nM (range 0.4 to 2.1 nM; n = 11) and 0.46 nM (range 0.2 to 2 nM; n = 10), respectively. In biochemical assays, dasabuvir inhibited a panel of genotype 1a and 1b polymerases with a mean IC50 value of 4.2 nM (range 2.2 to 10.7 nM; n = 7). Dasabuvir had lower potency (>200 times) against polymerases from other HCV genotypes (2a, 2b, 3a and 4a). The M1 metabolite of dasabuvir had 30‒40% lower potency than dasabuvir against genotypes 1a-H77 and 1b-Con1 in the HCV replicon assay.

Combination Activity in vitro

All two-drug combinations of paritaprevir, ombitasvir, dasabuvir and ribavirin demonstrated additive to synergistic inhibition of HCV genotype 1 replicon at the majority of drug concentrations studied in short term cell culture assays. In long term replicon survival assays, the ability of drug-resistant cells to form colonies in the presence of a single drug or drugs in combination was evaluated. In pair-wise combinations of paritaprevir, ombitasvir, and dasabuvir at concentrations 10-fold over their respective EC50, colony survival was reduced by more than 100-fold by two drugs as compared to each drug alone. When all three drugs were combined at concentrations of 5-fold above their respective EC50, no drug-resistant colonies survived.

Resistance in Cell Culture

Resistance to paritaprevir, ombitasvir, or dasabuvir conferred by variants in NS3, NS5A, or NS5B, respectively, selected in cell culture or identified in Phase 2b and 3 clinical trials were phenotypically characterised in the appropriate genotype 1a or 1b replicons.

In genotype 1a, substitutions F43L, R155 G/K/S, A156T, and D168A/E/F/H/N/V/Y in HCV NS3 reduced susceptibility to paritaprevir by 7- to 219-fold. The activity of paritaprevir in genotype 1a was not significantly affected (less than or equal to 3-fold) by single substitutions V23A (in NS4A), V36A/M, V55I, Y56H, Q80K or E357K. Double variants including combinations of V36M, F43L, Y56H, or E357K with R155K or with a D168 substitution reduced the activity of paritaprevir by an additional 2- to 7-fold relative to the single R155K or D168 substitution. In genotype 1b, substitutions A156T, D168A/H/V/Y, and Y56H in combination with D168A/V/Y in HCV NS3 reduced susceptibility to paritaprevir. In the genotype 1b replicon, the activity of paritaprevir was reduced 27- to 337-fold by D168A/H/V/Y substitutions. The combination of Y56H and D168A, D168V or D168Y reduced the activity of paritaprevir by an additional 12- to 26-fold relative to the single D168 substitution in genotype 1b replicons.

In genotype 1a, substitutions M28T/V, Q30E/R, H58D, Y93C/H/L/N in HCV NS5A reduced susceptibility to ombitasvir by 58- to 67,000 fold. In genotype 1b, substitutions L28T, L31F/V, and Y93H in HCV NS5A reduced susceptibility to ombitasvir 8- to 661 fold. In general, combinations of ombitasvir resistance-associated substitutions in HCV genotype 1a or 1b replicons further reduced ombitasvir antiviral activity.

In genotype 1a, substitutions C316Y, M4141/T, N444K, E446K/Q, Y448C/H, A553T, G554S, S556G/R, and Y561H in HCV NS5B reduced susceptibility to dasabuvir by 5- to 1472 fold. G558R and D559G/N were observed as treatment-emergent substitutions but the activity of dasabuvir against these variants could not be evaluated due to poor replication capacity. In genotype 1b, substitutions C316H/N/Y, S368T, N411S, M414I/T/V, Y448C/H, A553V, S556G and D559G in HCV NS5B reduced susceptibility to dasabuvir by 5- to 1569 fold. Dasabuvir retained full activity against replicons containing substitutions S282T in the nucleoside binding site, M423T in the lower thumb site, and P495A/S, P496S or V499A in the upper thumb site.

Effect of Baseline HCV Substitutions/Polymorphisms on Treatment Response

A pooled analysis of subjects in the Phase 2b and 3 clinical trials treated with paritaprevir, ombitasvir, and dasabuvir with or without ribavirin was conducted to explore the association between the baseline NS3/4A, NS5A or NS5B substitutions/polymorphisms and treatment outcome in recommended regimens.

In the greater than 500 genotype 1a baseline samples in this analysis, the most frequently observed resistance-associated variants were M28V (7.4%) in NS5A and S556G (2.9%) in NS5B. Q80K, although a highly prevalent polymorphism in NS3 (41.2% of samples), confers minimal resistance to paritaprevir. Resistance-associated variants at amino acid positions R155 and D168 in NS3 were rarely observed (less than 1%) at baseline. In the greater than 200 genotype 1b baseline samples in this analysis, the most frequently observed resistance-associated variants observed were Y93H (7.5%) in NS5A, and C316N (17.0%) and S556G (15%) in NS5B. Given the low virologic failure rates observed with recommended treatment regimens for HCV genotype 1a- and 1b-infected subjects, the presence of baseline variants appears to have little impact on the likelihood of achieving sustained virologic response (SVR, virologic cure).

Resistance in Clinical Studies

Of the 2,510 HCV genotype 1 infected subjects in the Phase 2b and 3 clinical trials treated with regimens containing paritaprevir, ombitasvir, and dasabuvir with or without ribavirin (for 8, 12, or 24 weeks), a total of 74 subjects (3%) experienced virologic failure (primarily post-treatment relapse). Treatment-emergent variants and their prevalence in these virologic failure populations are shown in Table 1. In the 67 genotype 1a infected subjects, NS3 variants were observed in 50 subjects, NS5A variants were observed in 46 subjects, NS5B variants were observed in 37 subjects, and treatment-emergent variants were seen in all 3 drug targets in 30 subjects. In the 7 genotype 1b infected subjects, treatment-emergent variants were observed in NS3 in 4 subjects, in NS5A in 2 subjects, and in both NS3 and NS5A in 1 subject. No genotype 1b infected subjects had treatment-emergent variants in all 3 drug targets.

Table 1. Treatment-Emergent Amino Acid Substitutions in the Pooled Analysis of VIEKIRA PAK/VIEKIRA PAK-RBV with and without Ribavirin Regimens in Phase 2b and Phase 3 Clinical Trials (N = 2510)
Target Emergent Amino Acid Substitutionsa Genotype 1a
N = 67b
% (n)
Genotype 1b
N = 7
% (n)
NS3 V55Ic 6 (4) -
Y56Hc 9 (6) 42.9 (3)d
I132Vc 6 (4) -
R155K 13.4 (9) -
D168A 6 (4) -
D168V 50.7 (34) 42.9 (3)d
D168Y 7.5 (5) -
V36Ac, V36Mc, F43Lc, D168H, E357Kc < 5% -
NS5A M28T 20.9 (14) -
M28Ve 9 (6)
Q30Re 40.3 (27) -
Y93H - 28.6 (2)
H58D, H58P, Y93N < 5% -
NS5B A553T 6.1 (4) -
S556G 33.3 (22) -
C316Y, M414T, G554S, S556R, G558R, D559G, D559N, Y561H < 5% -
a. Observed in at least 2 subjects of the same subtype.
b. N = 66 for the NS5B target.
c. Substitutions were observed in combination with other emergent substitutions at NS3 position R155 or D168.
d. Observed in combination in genotype 1b-infected subjects.
e. Observed in combination in 6% (4/67) of the subjects.

 Note: The following variants were selected in cell culture but were not treatment-emergent: NS3  variants A156T in genotype 1a, and R155Q and D168H in genotype 1b; NS5A variants Y93C/H in genotype  1a, and L31F/V or Y93H in combination with L28M, L31F/V or P58S in genotype 1b; and NS5B variants  Y448H in genotype 1a, and M414T and Y448H in genotype 1b.

Persistence of Resistance-Associated Substitutions

The persistence of paritaprevir, ombitasvir, and dasabuvir resistance-associated amino acid substitutions in NS3, NS5A, and NS5B, respectively, was assessed in genotype 1a-infected subjects in Phase 2b trials. Paritaprevir treatment-emergent variants V36A/M, R155K or D168V were observed in NS3 in 47 subjects. Ombitasvir treatment-emergent variants M28T, M28V or Q30R in NS5A were observed in 32 subjects. Dasabuvir treatment-emergent variants M414T, G554S, S556G, G558R or D559G/N in NS5B were observed in 34 subjects.

NS3 variants V36A/M and R155K and NS5B variants M414T and S556G remained detectable at post-treatment Week 48, whereas NS3 variant D168V and all other NS5B variants were not observed at post-treatment Week 48. All treatment-emergent variants in NS5A remained detectable at post-treatment Week 48. Due to high SVR rates in genotype 1b, trends in persistence of treatment-emergent variants in this genotype could not be established.

The lack of detection of virus containing a resistance-associated substitution does not indicate that the resistant virus is no longer present at clinically significant levels. The long-term clinical impact of the emergence or persistence of virus containing VIEKIRA PAK/VIEKIRA PAK-RBV-resistance-associated substitutions is unknown.

Cross-resistance

Cross-resistance is expected among NS5A inhibitors, NS3/4A protease inhibitors, and non-nucleoside NS5B inhibitors by class. The impact of prior ombitasvir, paritaprevir or dasabuvir treatment experience on the efficacy of other NS5A inhibitors, NS3/4A protease inhibitors, or NS5B inhibitors has not been studied.

Pharmacodynamic interactions

Co-administration with enzyme inducers may increase the risk of adverse events and ALT elevations. Co-administration with ethinylestradiol may increase the risk of ALT elevations (see INTERACTIONS WITH OTHER MEDICINES).

Pharmacokinetics

The pharmacokinetic properties of the combination of paritaprevir, ombitasvir, ritonavir, and dasabuvir have been evaluated in healthy adult subjects and in subjects with chronic hepatitis C. Table 2 shows geometric mean Cmax and AUC0-24 of paritaprevir/ritonavir/ombitasvir 150/10

0/25 mg once daily with dasabuvir 250 mg twice daily following multiple doses with food in healthy volunteers.

Table 2: Geometric Mean Cmax and AUC0-24 of Multiple Doses of paritaprevir/ritonavir/ombitasvir 150/100/25 mg Once Daily with Dasabuvir 250 mg Twice Daily with Food in Healthy Volunteers
Cmax (ng/mL) AUC0-24 (ng*hr/mL)
paritaprevir 1470 6990
ombitasvir 127 1420
dasabuvir 1030 13680
ritonavir 1600 9470

Absorption

Paritaprevir/ritonavir/ombitasvir and dasabuvir

Paritaprevir/ritonavir/ombitasvir and dasabuvir were absorbed after oral administration with mean Tmax of approximately 4 to 5 hours. While ombitasvir and dasabuvir exposures increased in a dose proportional manner, paritaprevir and ritonavir exposures increased in a more than dose proportional manner. Accumulation is minimal for ombitasvir and dasabuvir and approximately 1.5-to 2-fold for ritonavir and paritaprevir. Pharmacokinetic steady state for the combination is achieved after approximately 12 days of dosing.

Ribavirin

Ribavirin is absorbed rapidly following oral administration of a single dose (median Tmax = 1-2 hours). The mean terminal phase half-life of ribavirin following single doses of ribavirin ranges from 140 to 160 hours. Ribavirin data from the literature demonstrates absorption is extensive with approximately 10% of a radiolabelled dose excreted in the faeces. However, absolute bioavailability is approximately 45% to 65%, which appears to be due to first pass metabolism. There is an approximately linear relationship between dose and AUCt following single doses of 200 to 1,200 mg ribavirin. Mean apparent oral clearance of ribavirin following single 600 milligram doses ranges from 22 to 29 litres/hour. Volume of distribution is approximately 4,500 litres following administration of ribavirin. Ribavirin does not bind to plasma proteins.

Upon multiple dosing, ribavirin accumulates extensively in plasma with a six-fold ratio of multiple- dose to single-dose AUC12hr based on literature data. Following oral dosing with 600 mg BID, steady- state was reached by approximately 4 weeks, with mean steady state plasma concentrations of approximately 2,200 nanogram/mL.

Effects of Food on Oral Absorption
Paritaprevir/ritonavir/ombitasvir and dasabuvir

Paritaprevir, ritonavir, ombitasvir and dasabuvir should be administered with food. All clinical trials with paritaprevir, ritonavir, ombitasvir and dasabuvir have been conducted following administration with food.

Food increased the exposure (AUC) of paritaprevir, ombitasvir, ritonavir, and dasabuvir by up to 211%, 82%, 49%, and 30% respectively relative to the fasting state. The increase in exposure was similar regardless of meal type (e.g., high-fat versus moderate-fat) or calorie content (approximately 600 Kcal versus approximately 1000 Kcal). To maximise absorption, VIEKIRA PAK-RBV should be taken with food without regard to fat or calorie content.

Ribavirin

The bioavailability of a single oral 600 mg dose ribavirin was increased by co administration with a high fat meal. The ribavirin exposure parameters of AUC(0-192h) and Cmax increased by 42% and 66%, respectively, when ribavirin tablet was taken with a high fat breakfast compared to being taken in the fasted state. The clinical relevance of results from this single dose study is unknown. In order to achieve optimal ribavirin plasma concentrations, it is recommended to take ribavirin with food.

Distribution

Paritaprevir/ritonavir/ombitasvir and dasabuvir

Paritaprevir, ombitasvir, ritonavir and dasabuvir are highly bound to plasma proteins. Plasma protein binding is not meaningfully altered in patients with renal or hepatic impairment. The blood to plasma concentration ratios in humans ranged from 0.5 to 0.7, indicating that paritaprevir, ombitasvir, and dasabuvir were preferentially distributed in the plasma compartment of whole blood. Paritaprevir was approximately 97 to 98.6% bound to human plasma proteins over a concentration range of 0.08 to 8 microgram/mL. Ritonavir was greater than 99% bound to human plasma proteins over a concentration range of 0.007 to 22 microgram/mL. Ombitasvir was approximately 99.9% bound to human plasma proteins over a concentration range of 0.09 to 9 microgram /mL. Dasabuvir was > 99.5% bound to human plasma proteins over a concentration range of 0.15 to 5 microgram/mL.

In animals, paritaprevir liver levels are significantly higher than plasma levels (e.g. liver: plasma ratio of >300:1 in mouse). In vitro data indicate that paritaprevir is a substrate for the human hepatic uptake transporters, OATP1B1 and OATP1B3.

Ribavirin

Ribavirin has been shown to produce high inter- and intra-subject pharmacokinetic variability following single oral doses (intra-subject variability of approximately 30% for both AUC and Cmax), which may be due to extensive first pass metabolism and transfer within and beyond the blood compartment.

Ribavirin transport in non-plasma compartments has been most extensively studied in red cells, and has been identified to be primarily via an es-type equilibrative nucleoside transporter. This type of transporter is present on virtually all cell types and may account for the high volume of distribution of ribavirin. The ratio of whole blood to plasma ribavirin concentrations is approximately 60:1; the excess of ribavirin in whole blood exists as ribavirin nucleotides sequestered in erythrocytes.

Metabolism

Paritaprevir

Paritaprevir is metabolised predominantly by CYP3A4 and to a lesser extent CYP3A5. Following administration of a single 200/100 mg oral dose of 14C paritaprevir/ritonavir to humans, the parent drug was the major circulating component accounting for approximately 90% of the plasma radioactivity. At least 5 minor metabolites of paritaprevir have been identified in circulation that accounted for approximately 10% of plasma radioactivity. These metabolites are not expected to have antiviral activity.

Ombitasvir

Ombitasvir is metabolised via amide hydrolysis followed by oxidative metabolism. Following a 25 mg single dose of 14C-ombitasvir given alone, unchanged parent drug accounted for 8.9% of total radioactivity in human plasma; a total of 13 metabolites were identified in human plasma. These metabolites are not expected to have antiviral activity or off-target pharmacological activity.

Dasabuvir

Dasabuvir is predominantly metabolised by CYP2C8 and to a lesser extent by CYP3A. Following a 400 mg 14C-dasabuvir dose in humans, unchanged dasabuvir was the major component (approximately 60%) of drug related radioactivity in plasma; seven metabolites were identified in plasma. The most abundant plasma metabolite was M1, which represented 21% of drug-related radioactivity (AUC) in circulation and has similar contribution to activity against genotype 1 as the parent drug after accounting for difference in protein binding.

Ritonavir

Ritonavir is predominantly metabolised by CYP3A and to a lesser extent, by CYP2D6. Nearly the entire plasma radioactivity after a single 600 mg dose of 14C-ritonavir oral solution in humans was attributed to unchanged ritonavir.

Ribavirin

Ribavirin has two pathways of metabolism: i) a reversible phosphorylation pathway in nucleated cells; and (ii) a degradative pathway involving deribosylation and amide hydrolysis to yield a triazole carboxylic acid metabolite. Results of in vitro studies using both human and rat liver microsome preparations indicated little or no cytochrome P450 enzyme-mediated metabolism of ribavirin, with minimal potential for P450 enzyme-based drug interactions.

Elimination

Paritaprevir

Following dosing of paritaprevir/ritonavir/ombitasvir with or without dasabuvir, mean plasma half-life of paritaprevir was approximately 5.5 hours. Following a 200 mg 14C-paritaprevir dose with 100 mg ritonavir, approximately 88% of the radioactivity was recovered in faeces with limited radioactivity (8.8%) in urine.

Ombitasvir

Following dosing of paritaprevir/ritonavir/ombitasvir with or without dasabuvir, mean plasma half-life of ombitasvir was approximately 21-25 hours. Following a 25 mg 14C-ombitasvir dose, approximately 90.2% of the radioactivity was recovered in faeces with limited radioactivity (1.91%) in urine.

Dasabuvir

Following dosing of dasabuvir with paritaprevir/ritonavir/ombitasvir, mean plasma half-life of dasabuvir was approximately 5.5 to 6 hours. Following a 400 mg 14C-dasabuvir dose, approximately 94.4% of the radioactivity was recovered in faeces with limited radioactivity (approximately 2%) in urine.

Ritonavir

Following dosing of paritaprevir/ritonavir/ombitasvir, mean plasma half-life of ritonavir was approximately 4 hours. Following a 600 mg dose of 14C -ritonavir oral solution, 86.4% of the radioactivity was recovered in the faeces and 11.3% of the dose was excreted in the urine.

Ribavirin

Ribavirin and its triazole carboxamide and triazole carboxylic acid metabolites are excreted renally. After oral administration of 600 mg of 14C-ribavirin, approximately 61% and 12% of the radioactivity was eliminated in the urine and faeces respectively, in 336 hours. Unchanged ribavirin accounted for 17% of the administered dose.

Upon discontinuation of dosing, the mean half-life was 298 (30%) hours, which probably reflects slow elimination from non-plasma compartments. Multiple dose ribavirin apparent clearance was 22.4 (34%) L/hr.

Implications for Drug Interactions

Potential for VIEKIRA PAK-RBV to affect the pharmacokinetics of other medicinal products

In vivo drug interaction studies evaluated the net effect of the combination treatment, including ritonavir.

The following section describes the specific transporters and metabolizing enzymes that are affected by VIEKIRA PAK-RBV. See INTERACTIONS WITH OTHER MEDICINES for guidance regarding potential interactions with other medicinal products and dosing recommendations.

Medicinal products metabolised by CYP3A4

Ritonavir is a strong inhibitor of CYP3A. Co-administration of VIEKIRA PAK-RBV with medicinal products primarily metabolised by CYP3A may result in increased plasma concentrations of these medicinal products. Medicinal products that are highly dependent on CYP3A for clearance and for which elevated plasma levels are associated with serious events are contraindicated (see CONTRAINDICATIONS and INTERACTIONS WITH OTHER MEDICINES).

CYP3A substrates evaluated in drug interaction studies which may require dose adjustment and/or clinical monitoring include cyclosporine, tacrolimus, amlodipine and alprazolam (see Table 13). Examples of other CYP3A4 substrates which may require dose adjustment and/or clinical monitoring include calcium channel blockers (e.g. nifedipine), and trazodone. Although buprenorphine and zolpidem are also metabolised by CYP3A, drug interaction studies indicate that no dose adjustment is needed when co-administering these medicinal products with VIEKIRA PAK-RBV (see Table 13).

Medicinal products transported by the OATP family and OCT1

Paritaprevir is an inhibitor of the hepatic uptake transporters OATP1B1 and OATP1B3, and paritaprevir and ritonavir are inhibitors of OATP2B1. Ritonavir is an in vitro inhibitor of OCT1, but the clinical relevance is unknown. Co-administration of VIEKIRA PAK-RBV with medicinal products that are substrates of OATP1B1, OATP1B3, OATP2B1 or OCT1 may increase plasma concentrations of these transporter substrates, potentially requiring dose adjustment/clinical monitoring. Such medicinal products include some statins (see Table 13), fexofenadine, repaglinide and angiotensin II receptor antagonists (e.g., valsartan).

OATP1B1/3 substrates evaluated in drug interaction studies include pravastatin and rosuvastatin (see Table 13).

Medicinal products transported by BCRP

Paritaprevir, ritonavir and dasabuvir are inhibitors of BCRP in vivo. Co-administration of VIEKIRA PAK-RBV together with medicinal products that are substrates of BCRP may increase plasma concentrations of these transporter substrates, potentially requiring dose adjustment/clinical monitoring. Such medicinal products include sulfasalazine, imatinib and some of the statins (see Table 13).

BCRP substrates evaluated in drug interaction studies include rosuvastatin (see Table 13).

Medicinal products transported by P-gp in the intestine

While paritaprevir, ritonavir and dasabuvir are in vitro inhibitors of P-gp, no significant change was observed in the exposure of the P-gp substrate digoxin when administered with VIEKIRA PAK-RBV and dasabuvir (see Table 13). VIEKIRA PAK-RBV may increase the plasma exposure to medicinal products that are sensitive for changed intestinal P-gp activity (such as dabigatran etexilate).

Medicinal products metabolised by glucuronidation (UGT1A1)

Paritaprevir, ombitasvir and dasabuvir are inhibitors of UGT1A1. Co-administration of VIEKIRA PAK-RBV with medicinal products that are primarily metabolised by UGT1A1 result in increased plasma concentrations of such medicinal products; routine clinical monitoring is recommended for narrow therapeutic index medicinal products (i.e. levothyroxine). See also Table 13 for specific advice on raltegravir and buprenorphine, which have been evaluated in drug interaction studies.

Medicinal products metabolised by CYP2C19

Co-administration of VIEKIRA PAK-RBV can decrease exposures of medicinal products that are metabolised by CYP2C19 (e.g. lansoprazole, esomeprazole, s-mephenytoin), which may require dose adjustment/clinical monitoring. CYP2C19 substrates evaluated in drug interaction studies include omeprazole and escitalopram (see Table 13).

Medicinal products metabolised by CYP2C9

VIEKIRA PAK-RBV did not affect the exposures of the CYP2C9 substrate, warfarin. Other CYP2C9 substrates (NSAIDs (e.g. ibuprofen), antidiabetics (e.g. glimepiride, glipizide) are not expected to require dose adjustments.

Medicinal products metabolised by CYP2D6 or CYP1A2

VIEKIRA PAK-RBV did not affect the exposures of the CYP2D6/CYP1A2 substrate, duloxetine. Other CYP1A2 substrates (e.g. ciprofloxacin, theophylline and caffeine) and CYP2D6 substrates (e.g. desipramine, metoprolol and dextromethorphan) are not expected to require dose adjustments.

Medicinal products renally excreted via transport proteins

Ombitasvir, paritaprevir, dasabuvir and ritonavir do not inhibit organic anion transporter (OAT1) invivo as shown by the lack of interaction with tenofovir (OAT1 substrate). In vitro studies show that ombitasvir, paritaprevir, dasabuvir and ritonavir are not inhibitors of organic cation transporters (OCT2), organic anion transporters (OAT3), or multidrug and toxin extrusion proteins (MATE1 and MATE2K) at clinically relevant concentrations.

Therefore, VIEKIRA PAK-RBV is not expected to affect medicinal products which are primarily excreted by the renal route via these transporters.

Potential for other medicinal products to affect the pharmacokinetics of ombitasvir, paritaprevir, and dasabuvir
Medicinal products that inhibit CYP3A4

Co-administration of VIEKIRA PAK-RBV with strong inhibitors of CYP3A may increase paritaprevir concentrations up to 2-fold (see Table 13).

Enzyme inducers

Co-administration of VIEKIRA PAK-RBV with medicinal products that are moderate or strong enzyme inducers is expected to decrease ombitasvir, paritaprevir, ritonavir and dasabuvir plasma concentrations and reduce their therapeutic effect. Contraindicated enzyme inducers are provided under CONTRAINDICATIONS and INTERACTIONS WITH OTHER MEDICINES.

Medicinal products that inhibit CYP3A4 and transport proteins

Paritaprevir is eliminated via CYP3A4 mediated metabolism and biliary excretion (substrate of the hepatic transporters OATP1B1, P-gp and BCRP). Caution is advised if co-administering VIEKIRA PAK-RBV with medicinal products that are both moderate inhibitors of CYP3A4 and inhibitors of multiple transporters (P-gp, BCRP and/or OATP1B1/ OATP1B3). These medicinal products may show clinically relevant increases in exposures of paritaprevir (e.g., ritonavir with atazanavir, erythromycin, diltiazem or verapamil).

Medicinal products that inhibit transport proteins

Potent inhibitors of P-gp, BCRP, OATP1B1 and/or OATP1B3 have the potential to increase the exposure to paritaprevir. Inhibition of these transporters is not expected to show clinically relevant increases in exposures of ombitasvir and dasabuvir.

Special Populations

Renal Impairment
Paritaprevir/ritonavir/ombitasvir and dasabuvir

Based on the pharmacokinetic data in HCV uninfected subjects (n=24), no dose adjustment of paritaprevir/ritonavir/ombitasvir is recommended in subjects with mild, moderate or severe renal impairment (see DOSAGE and ADMINISTRATION for Dosage Modification of RBV). The efficacy and safety of VIEKIRA PAK-RBV have not been evaluated in HCV-infected subjects with moderate or severe renal impairment. Pharmacokinetics of the combination of paritaprevir 150 mg, ombitasvir 25 mg, and ritonavir 100 mg, with or without dasabuvir 400 mg were evaluated in subjects with mild (CrCl: 60 to 89 mL/min), moderate (CrCl: 30 to 59 mL/min) and severe (CrCl: 15 to 29 mL/min) renal impairment.

In subjects with mild renal impairment (n=6), paritaprevir mean Cmax and AUC values were comparable (up to 19% higher), ombitasvir mean Cmax and AUC values were comparable (up to 7% lower), and ritonavir mean Cmax and AUC values were 26% to 42% higher and dasabuvir mean Cmax and AUC values were 5% to 21% higher compared to subjects with normal renal function.

In subjects with moderate renal impairment (n=6), paritaprevir mean Cmax values were comparable (< 1% increase) and AUC values were 33% higher, ombitasvir mean Cmax and AUC values were comparable (up to 12% lower), and ritonavir mean Cmax and AUC value were 48% to 80% and dasabuvir mean Cmax and AUC values were 9% to 37% higher compared to subjects with normal renal function.

In subjects with severe renal impairment (n=6), paritaprevir mean Cmax values were comparable (< 1% increase) and AUC values were 45% higher, ombitasvir mean Cmax and AUC values were comparable (up to 15% lower), and ritonavir mean Cmax and AUC value were 66% to 114% higher and dasabuvir mean Cmax and AUC values were 12% to 50% higher compared to subjects with normal renal function.

Ribavirin

The apparent clearance of ribavirin is reduced in patients with creatinine clearance ≤50 mL/min, including patients with end-stage-renal disease (ESRD) on chronic haemodialysis, exhibiting approximately 30% of the value found in patients with normal renal function. Based on a small study in patients with moderate or severe renal impairment (creatinine clearance ≤50 mL/min) receiving reduced daily doses of 600 mg and 400 mg of ribavirin, respectively, ribavirin plasma exposure (AUC) was found to be higher compared to patients with normal renal function (creatinine clearance >80 mL/min) receiving the standard ribavirin dose. Patients with ESRD on chronic haemodialysis who received 200 mg daily doses of ribavirin, exhibited mean ribavirin exposure (AUC) approximately 80% of the value found in patients with normal renal function receiving the standard 1000/1200 mg ribavirin daily dose. Plasma ribavirin is removed by haemodialysis with an extraction ratio of approximately 50%; however, due to the large volume of distribution of ribavirin, significant amounts of ribavirin are not effectively removed from the body by haemodialysis. Increased rates of adverse drug reactions were observed in patients with moderate and severe renal impairment receiving the doses evaluated in this study. Though the dose of ribavirin would need to be reduced if used in patients with significant renal impairment, there are insufficient data on the safety and efficacy of ribavirin in such patients to support specific recommendations for dose adjustments (see DOSAGE AND ADMINISTRATION).

Hepatic Impairment

The changes in paritaprevir, ombitasvir, dasabuvir and ritonavir exposures in subjects with mild and moderate hepatic impairment are not considered clinically significant. No dosage adjustment of VIEKIRA PAK-RBV is required in patients with mild hepatic impairment (Child-Pugh A). VIEKIRA PAK-RBV is not recommended in patients with moderate hepatic impairment (Child-Pugh B). A decision to initiate treatment in patients with Child-Pugh B should be guided by assessment of the potential benefits and risks for the individual. VIEKIRA PAK-RBV is contraindicated in patients with severe hepatic impairment (Child-Pugh C) (see CONTRAINDICATIONS and PRECAUTIONS).

Pharmacokinetics of the combination of paritaprevir 200 mg, and ritonavir 100 mg, ombitasvir 25 mg, and dasabuvir 400 mg were evaluated in subjects (n=17) with mild (Child-Pugh A), moderate (Child-Pugh B) and severe (Child-Pugh C) hepatic impairment.

In subjects with mild hepatic impairment (n=6), paritaprevir, ritonavir and ombitasvir mean Cmax and AUC values decreased by 29% to 48%, 34% to 40% and up to 8%, respectively, and dasabuvir mean Cmax and AUC values were 17% to 24% higher compared to subjects with normal hepatic function.

In subjects with moderate hepatic impairment (n=6), paritaprevir mean Cmax and AUC value increased by 26% to 62%, ombitasvir and ritonavir mean Cmax and AUC values decreased by 29% to 30% and 30% to 33%, respectively, and dasabuvir mean Cmax and AUC values were 16% to 39% lower compared to subjects with normal hepatic function. The safety and efficacy of VIEKIRA PAK-RBV have not been established in HCV-infected patients with moderate hepatic impairment (Child-Pugh B); however, no dose adjustment is expected to be required based on pharmacokinetic studies.

In subjects with severe hepatic impairment (n=5), paritaprevir and dasabuvir mean Cmax and AUC values increased by 3.2 to 9.5-fold and 0.3- to 3.3-fold respectively; ritonavir mean Cmax values were 35% lower and AUC values were 13% higher and ombitasvir mean Cmax and AUC values decreased by 68% and 54% respectively compared to subjects with normal hepatic function.

Single-dose pharmacokinetics of ribavirin in patients with mild, moderate or severe hepatic dysfunction (Child-Pugh Classification A, B or C) are similar to those of normal controls.

Elderly

No dose adjustment is necessary for paritaprevir/ritonavir/ombitasvir or dasabuvir in elderly patients.

Based on population pharmacokinetic analysis of data from Phase 3 clinical studies, a 10 year increase or decrease in age from 54 years (median age in the Phase 3 studies) would result in approximately 10% change in ombitasvir exposures, less than 10% change in dasabuvir exposures and ≤20% change in paritaprevir exposures. There is no pharmacokinetic information in patients >75 years.

In a published population pharmacokinetic study, renal function was the determining factor in the kinetics of ribavirin, while age was not a key factor. The risk of toxic reactions to this drug may be greater in patients with impaired renal function. The dose of ribavirin should be reduced in patients with creatinine clearance 50 mL/min (see DOSAGE AND ADMINISTRATION).

Paediatric Population (<18 years)

The pharmacokinetics, safety and efficacy of VIEKIRA PAK-RBV in paediatric patients have not been established.

Race or Ethnicity

No dose adjustment is necessary for paritaprevir/ritonavir/ombitasvir or dasabuvir based on race or ethnicity. Based on population pharmacokinetic analysis of data from Phase 3 clinical studies, Asian subjects had 18% to 21%, 37% to 39% and 29% to 39% higher ombitasvir, paritaprevir and dasabuvir exposures, respectively, than non-Asian subjects. The ritonavir exposures were comparable between Asians and non-Asians. However, patient numbers in the clinical trials were not sufficient to definitively address possible differences in pharmacokinetics and toxicity profiles in specific ethnic groups such as Asian patients.

Sex or Body weight

No dose adjustment is necessary for paritaprevir/ritonavir/ombitasvir or dasabuvir based on gender or body weight.

Based on population pharmacokinetic analysis of data from Phase 3 clinical studies, female subjects would have approximately 55%, 100%, 15% and 21% higher ombitasvir, paritaprevir, ritonavir and dasabuvir exposures (AUC), respectively, than male subjects. A 10 kg change in body weight from 76 kg (median weight in the Phase 3 studies) would results in <10% change in ombitasvir and dasabuvir exposures, and no change in paritaprevir exposures. Body weight is not a significant predictor of ritonavir exposures.

Dose adjustment is required for ribavirin based on weight (see DOSAGE and ADMINISTRATION).

Clinical Trials

The efficacy and safety of VIEKIRA PAK and VIEKIRA PAK-RBV were evaluated in six randomised Phase 3 clinical trials, in over 2,300 subjects with genotype 1 chronic hepatitis C infection. Included in the Phase 3 program was one trial exclusively in subjects with cirrhosis (Child-Pugh A). Phase 3 trials are summarised in Table 3.

Table 3: Phase 3 Randomised, Global Multicentre Trials Conducted with VIEKIRA PAK with or without ribavirin (RBV).
Trial1 Number of subjects (treated2) HCV Genotype (GT) Summary of Study Design3
Treatment-naïve4, without cirrhosis
SAPPHIRE I 631 GT1 Arm A: VIEKIRA PAK + RBV
Arm B: Placebo
PEARL III 419 GT1b Arm A: VIEKIRA PAK+ RBV
Arm B: VIEKIRA PAK
PEARL IV 305 GT1a Arm A: VIEKIRA PAK+ RBV
Arm B: VIEKIRA PAK
Treatment-experienced5, without cirrhosis
SAPPHIRE II 394 GT1 Arm A: VIEKIRA PAK + RBV
Arm B: Placebo
PEARL II (open-label) 180 GT1b Arm A: VIEKIRA PAK+ RBV
Arm B: VIEKIRA PAK
Treatment-naïve and treatment-experienced5, with compensated cirrhosis
TURQUOISE II
(open-label)
380 GT1 Arm A: VIEKIRA PAK + RBV (12 weeks)
Arm B: VIEKIRA PAK + RBV (24 weeks)
1 Double-blind unless otherwise noted
2 Treated is defined as subjects who were randomised and received at least one dose of VIEKIRA PAK.
3 Treatment duration was 12 weeks for all arms, except for TURQUOISE II which included a 24 week arm. 4 Treatment naïve was defined as not having received any prior therapy for HCV infection.
5 Treatment-experienced subjects were defined as either: prior relapsers (subjects with HCV RNA undetectable at or after the end of at least 36 weeks of pegIFN/RBV treatment, but HCV RNA was detectable within 52 weeks of treatment follow-up) or prior partial responders (received at least 20  weeks of pegIFN/RBV and achieved a greater than or equal to 2 log10  IU/mL reduction in HCV RNA at week 12, but not achieving HCV RNA undetectable at end of treatment) or prior null-responders (received at least 12 weeks of pegIFN/RBV treatment and failed to achieve a 2 log10  IU/mL reduction in HCV RNA at week 12 or received at least 4 weeks of pegIFN/RBV treatment and achieved a < 1 log10  IU/mL reduction  in HCV RNA at week 4).

In all six trials, the paritaprevir/ritonavir/ombitasvir dose was 150/100/25 mg once daily and the dasabuvir dose was 250 mg twice daily. For subjects who received ribavirin, the ribavirin dose was 1000 mg per day for subjects weighing less than 75 kg or 1200 mg per day for subjects weighing greater than or equal to 75 kg.

Sustained virologic response (virologic cure) was defined as unquantifiable or undetectable HCV RNA 12 weeks after the end of treatment (SVR12) in the Phase 3 trials. Treatment duration was fixed in each trial and was not guided by subjects’ HCV RNA levels (no response-guided algorithm). Plasma HCV RNA values were measured during the clinical trials using the COBAS TaqMan HCV test (version 2.0), for use with the High Pure System. The assay had a lower limit of quantification (LLOQ) of 25 IU per mL.

Pooled Analyses of Clinical Trials

Durability of Response

Overall, 660 subjects in Phase 2 and 3 clinical trials had HCV RNA results for both the SVR12 and SVR24 time points. Among these subjects, the positive predictive value of SVR12 on SVR24 was 99.8%.

Pooled Efficacy Analyses

In phase 3 clinical trials, 1096 subjects (including 202 with cirrhosis) received the recommended regimen for their HCV subtype, cirrhosis status and previous treatment. Table 4 shows SVR rates for these patients.

Among subjects who received the recommended regimen, 97% achieved SVR (95% with cirrhosis and 97% without cirrhosis), while 0.5% demonstrated virologic breakthrough and 1.6% experienced post-treatment relapse.

Table 4: SVR12 rates for recommended treatment regimens
  Genotype 1a Genotype 1b
No Cirrhosis VIEKIRA PAK- RBV With Cirrhosis VIEKIRA PAK-RBV No cirrhosis VIEKIRA PAK With cirrhosis VIEKIRA PAK-RBV
12 weeks 12 weeks* 12 weeks 12 weeks
Treatment-naïve 96% (403/420) 92% (61/66) 100% (210/210) 100% (22/22)
Treatment- experienced 96% (166/173) 94% (64/68)* 100% (91/91) 98% (45/46)
Prior pegIFN/RBV relapser 94% (47/50) 93%  (14/15) 100% (33/33) 100% (14/14)
Prior pegIFN/RBV partial responder 100% (36/36) 100% (11/11) 100% (26/26) 86% (6/7)
Prior pegIFN/RBV null responder 95% (83/87) 93% (39/42)
(24 weeks)
100% (32/32) 100% (25/25)
TOTAL 96% (569/593) 93% (125/134)* 100%  (301/301) 99%  (67/68)
*All subjects received 12 weeks of therapy except for genotype 1a infected prior null responders with cirrhosis who received 24 weeks of therapy.

Impact of Ribavirin Dose Adjustment on Probability of SVR

In Phase 3 clinical trials, 91.5% of subjects did not require ribavirin dose adjustments during therapy. In the 8.5% of subjects who had ribavirin dose adjustments during therapy, the SVR rate (98.5%) was comparable to subjects who maintained their starting ribavirin dose throughout treatment.

Clinical Trials in Treatment-Naïve Adults

SAPPHIRE-I (M11-646) - Genotype 1, Treatment-Naïve

SAPPHIRE-I was a randomised, global multicentre, double-blind, placebo-controlled trial conducted in 631 treatment-naïve adults with genotype 1 chronic hepatitis C virus infection without cirrhosis. VIEKIRA PAK-RBV was given for 12 weeks of treatment. Subjects randomised to the placebo arm received placebo for 12 weeks, after which they received open-label VIEKIRA PAK-RBV for 12 weeks.

Treated subjects (N=631) had a median age of 52 years (range: 18 to 70); 64.8% were born between 1945 – 1965; 54.5% were male; 5.4% were Black and 5.1% were Hispanic or Latino; 16.2% had a body mass index of at least 30 kg/m2; 15.2% had a history of depression or bipolar disorder; 69.3% had IL28B non-CC genotype; 79.1% had baseline HCV RNA levels at least 800,000 IU/mL; 15.4% had portal fibrosis (F2) and 8.7% had bridging fibrosis (F3); 67.7% had HCV genotype 1a infection; 32.3% had HCV genotype 1b infection.

Table 5 shows the SVR12 rates for genotype 1-infected, treatment-naïve subjects receiving VIEKIRA PAK-RBV for 12 weeks in SAPPHIRE-I.

Table 5: SVR12 for Genotype 1-Infected Treatment-Naïve Subjects in SAPPHIRE-I
  VIEKIRA PAK-RBV for 12 Weeks
Treatment Outcome n/N % 95% CI
Overall SVR12 456/473 96,4 94.7, 98.1
HCV genotype 1a 308/322 95,7 93.4, 97.9
HCV genotype 1b 148/151 98,0 95.8, 100.0
       
Outcome for subjects without SVR12      
On-treatment VFa 1/473 0,2  
Relapseb 7/463 1,5  
Otherc 9/473 1,9  
CI = confidence interval, VF = virologic failure
a.    On-treatment VF was defined as confirmed HCV ≥ 25 IU/mL after HCV RNA < 25 IU/mL during treatment, confirmed 1 log10 IU/mL increase in HCV RNA from nadir, or HCV RNA persistently ≥ 25 IU/mL with at least 6 weeks of treatment.
b.    Relapse was defined as confirmed HCV RNA ≥ 25 IU/mL post-treatment before or during SVR12 window among subjects with HCV RNA < 25 IU/mL at last observation during at least 11 weeks of treatment.
c.    Other includes subjects not achieving SVR12 but not experiencing on-treatment VF or relapse (e.g. missing HCV RNA values in the SVR12 window).

In the primary efficacy analysis, VIEKIRA PAK-RBV demonstrated superiority to the historical control SVR rate of 78% {95% CI of 75%, 80%} (based upon telaprevir plus peginterferon (pegIFN/RBV)) for subjects with genotype 1 HCV infection who were treatment-naïve without cirrhosis. Refer to the telaprevir prescribing information.

No subjects with HCV genotype 1b infection experienced on-treatment virologic failure and one subject with HCV genotype 1b infection experienced relapse.

Based on subgroup analyses, the following baseline factors were not associated with lower SVR12 rates (lower 95% confidence bound > 70%):

  • Viral factors: genotype 1 subtype, baseline viral load
  • Host factors: Gender, race, ethnicity, age, birth year (1945 – 1965), IL28B allele, baseline body mass index, history of depression or bipolar disorder, fibrosis stage

In addition, subjects who underwent ribavirin dose modifications did not have lower SVR12 rates.

Significantly more subjects (352/363 = 97.0%) who received VIEKIRA PAK-RBV had normalised ALT by the end of treatment than those who received placebo (18/114 = 15.8%); P value < 0.001.

PEARL-III (M13-961) – Genotype 1b, Treatment-Naïve

PEARL-III was a randomised, global multi-centre, double-blind, controlled trial conducted in 419 treatment-naïve adults with genotype 1b chronic hepatitis C virus infection without cirrhosis. Subjects were randomised in a 1:1 ratio to receive VIEKIRA PAK or VIEKIRA PAK-RBV for 12 weeks of treatment.

Treated subjects (N=419) had a median age of 50 years (range: 19 to 70); 54.9% were born between 1945 – 1965, 45.8% were male; 4.8% were Black; 1.7% were Hispanic or Latino; 16.5% had a body mass index of at least 30 kg/m2; 9.3% had a history of depression or bipolar disorder; 79.0% had IL28B non-CC genotype; 73.3% had baseline HCV RNA of at least 800,000 IU/mL; 20.3% had portal fibrosis (F2) and 10.0% had bridging fibrosis (F3).

Table 6 shows the SVR12 rates for genotype 1b-infected, treatment-naïve subjects who received VIEKIRA PAK or VIEKIRA PAK-RBV for 12 weeks in PEARL III. In this study, VIEKIRA PAK had similar SVR12 rates (100%) compared to VIEKIRA PAK-RBV (99.5%).

Table 6: SVR12 for Genotype 1b-Infected Treatment-Naïve Subjects in PEARL III
  VIEKIRA PAK-RBV for 12 weeks VIEKIRA PAK for 12 weeks
  n/N % 95% CI n/N % 95% CI
Overall SVR12 209/210 99,5 98.6, 100.0 209/209 100 98.2, 100.0
             
Outcome for subjects without SVR12 1/210 0,5   2/209 1,0  
On-treatment VFa 1/210 0,5   0/209 0  
Relapseb 0/210 0   0/209 0  
Otherc 0/210 0   0/209 0  
CI = confidence interval, VF = virologic failure
a.     On-treatment VF was defined as confirmed HCV ≥ 25 IU/mL after HCV RNA < 25 IU/mL during treatment, confirmed 1 log10  IU/mL increase in HCV RNA from nadir, or HCV RNA persistently ≥ 25 IU/mL with at least 6 weeks of treatment.
b.     Relapse was defined as confirmed HCV RNA ≥ 25 IU/mL post-treatment before or during SVR12 window among subjects with HCV RNA < 25 IU/mL at last observation during at least 11 weeks of treatment.
c.    Other includes subjects not achieving SVR12 but not experiencing on-treatment VF or relapse (e.g. missing HCV RNA values in the SVR12 window).

In the primary efficacy analysis, VIEKIRA PAK and VIEKIRA PAK-RBV demonstrated superiority to the historical control SVR rate of 80% {95% CI of 75%, 84%} (based upon telaprevir plus pegIFN/RBV) for subjects with genotype 1b HCV infection who were treatment-naïve without cirrhosis. Refer to the telaprevir prescribing information.

Based on subgroup analyses, the following baseline factors were not associated with lower SVR12 rates (lower 95% confidence bound > 73%):

  • Viral factors: baseline viral load
  • Host factors: Gender, race, ethnicity, age, birth year (1945 – 1965), IL28B allele, baseline body mass index, history of depression or bipolar disorder, fibrosis stage

In addition, subjects who underwent ribavirin dose modifications did not have lower SVR12 rates.

PEARL-IV (M14-002) – Genotype 1a, Treatment-Naïve

PEARL-IV was a randomised, global multicentre, double-blind, controlled trial conducted in 305 treatment-naïve adults with genotype 1a chronic hepatitis C virus infection without cirrhosis. Subjects were randomised in a 1:2 ratio to receive VIEKIRA PAK or VIEKIRA PAK-RBV for 12 weeks of treatment.

Treated subjects (N=305) had a median age of 54 years (range: 19 to 70); 72.5% were born between 1945 – 1965, 65.2% were male; 11.8% were Black; 9.2% were Hispanic or Latino; 19.7% had a body mass index of at least 30 kg/m2; 20.7% had a history of depression or bipolar disorder; 69.2% had IL28B non-CC genotype; 86.6% had baseline HCV RNA levels of at least 800,000 IU/mL; 18.4% had portal fibrosis (F2) and 17.7% had bridging fibrosis (F3).

Table 7 shows the SVR12 rates for genotype 1a-infected, treatment-naïve subjects who received VIEKIRA PAK or VIEKIRA PAK-RBV for 12 weeks in PEARL IV. VIEKIRA PAK was not non-inferior to VIEKIRA PAK-RBV.

Table 7: SVR12 for Genotype 1a-Infected Treatment-Naïve Subjects in PEARL IV
  VIEKIRA PAK-RBV for 12 weeks VIEKIRA PAK for 12 weeks
n/N % 95% CI n/N % 95% CI
Overall SVR12 97/100 97,0 93.7, 100.0 185/205 90,2 86.2, 94.3
Outcome for subjects without SVR12            
On-treatment VFa 1/100 1,0   6/205 2,9  
Relapseb 1/98 1,0   10/194 5,2  
Otherc 1/100 1,0   1/205 0,5  
CI = confidence interval, VF = virologic failure
a.    On-treatment VF was defined as confirmed HCV ≥ 25 IU/mL after HCV RNA < 25 IU/mL during treatment, confirmed 1 log10  IU/mL increase in HCV RNA from nadir, or HCV RNA persistently ≥ 25 IU/mL with at least 6 weeks of treatment.
b.    Relapse was defined as confirmed HCV RNA ≥ 25 IU/mL post-treatment before or during SVR12 window among subjects with HCV RNA <25 IU/mL at last observation during at least 11 weeks of treatment.
c.    Other includes subjects not achieving SVR12 but not experiencing on-treatment VF or relapse (e.g. missing HCV RNA values in the SVR12 window).

In the primary efficacy analysis, VIEKIRA PAK and VIEKIRA PAK-RBV demonstrated superiority to the historical control SVR rate of 72% {95% CI of 68%, 75%} (based upon telaprevir plus pegIFN/RBV) for subjects with genotype 1a HCV infection who were treatment-naïve without cirrhosis. Refer to the telaprevir prescribing information.

Based on subgroup analyses, the following baseline factors were not associated with lower SVR12 rates (lower 95% confidence bound > 65%) :

  • Viral factors: baseline viral load
  • Host factors: Gender, race, ethnicity, age, birth year (1945 – 1965), IL28B allele, baseline body mass index, history of depression or bipolar disorder, fibrosis stage

In addition, subjects who underwent ribavirin dose modifications did not have lower SVR12 rates.

Clinical Trials in Treatment-Experienced Adults

SAPPHIRE-II (M13-098) Genotype 1 – Treatment-experienced

SAPPHIRE-II was a randomised, global multicentre, double-blind, placebo-controlled trial conducted in 394 subjects with genotype 1 chronic hepatitis C virus infection without cirrhosis who did not achieve SVR with prior treatment with pegIFN/RBV. VIEKIRA PAK-RBV was given for 12 weeks of treatment. Subjects randomised to the placebo arm received placebo for 12 weeks, after which they received VIEKIRA PAK-RBV for 12 weeks.

Treated subjects (N=394) had a median age of 54 years (range: 19 to 71); 49.0% were prior pegIFN/RBV null responders; 21.8% were prior pegIFN/RBV partial responders, and 29.2% were prior pegIFN/RBV relapsers; 73.9% were born between 1945 – 1965; 57.6% were male; 8.1% were Black and 6.3% were Hispanic or Latino; 19.8% had a body mass index of at least 30 kg/m2; 20.6% had a history of depression or bipolar disorder; 89.6% had IL28B non-CC genotype; 87.1% had baseline HCV RNA levels at least 800,000 IU per mL; 17.8% had portal fibrosis (F2) and 14.5% had bridging fibrosis (F3); 58.4% had HCV genotype 1a infection; 41.4% had HCV genotype 1b infection.

Table 8: SVR12 for Genotype 1-infected Treatment-Experienced Subjects in SAPPHIRE-II
Treatment Outcome VIEKIRA PAK–RBV for 12 weeks
n/N % 95% CI
Overall SVR12 286/297 96,3 94.1, 98.4
HCV Genotype 1a 166/173 96,0 93.0, 98.9
Prior pegIFN/RBV null responder 83/87 95,4 91.0, 99.8
Prior pegIFN/RBV partial  responder 36/36 100 100.0, 100.0
Prior pegIFN/RBV relapser 47/50 94,0 87.4, 100.0
HCV Genotype 1b 119/123 96,7 93.6, 99.9
Prior pegIFN/RBV null responder 56/59 94,9 89.3, 100.0
Prior pegIFN/RBV partial  responder 28/28 100 100.0, 100.0
Prior pegIFN/RBV relapser 35/36 97,2 91.9, 100.0
Outcome for subjects without SVR12      
On-treatment VFa 0/297 0  
Relapseb 7/293 2,4  
Otherc 4/297 1,3  
CI = confidence interval, VF = virologic failure
a.      On-treatment VF was defined as confirmed HCV ≥ 25 IU/mL after HCV RNA < 25 IU/mL during treatment, confirmed 1 log10  IU/mL increase in HCV RNA from nadir, or HCV RNA persistently ≥ 25 IU/mL with at least 6 weeks of treatment.
b.      Relapse was defined as confirmed HCV RNA ≥ 25 IU/mL post-treatment before or during SVR12 window among subjects with HCV RNA < 25 IU/mL at last observation during at least 11 weeks of treatment.
c        Other includes subjects not achieving SVR12 but not experiencing on-treatment VF or relapse (e.g. missing HCV RNA values in the SVR12 window).

No subjects with HCV genotype 1b infection experienced on-treatment virologic failure and 2 subjects with HCV genotype 1b infection experienced relapse.

In the primary efficacy analysis, VIEKIRA PAK-RBV demonstrated superiority to the historical control SVR rate of 65% {95% CI of 60%, 70%} (based upon telaprevir plus pegIFN/RBV) for subjects with genotype 1 HCV infection who were treatment-experienced without cirrhosis. Refer to the telaprevir prescribing information.

Significantly more subjects (217/224 = 96.9%) who received VIEKIRA PAK-RBV had normalised ALT by the end of treatment than those who received placebo (Arm B, 10/78=12.8%); P value < 0.001.

Based on subgroup analyses, the following baseline factors were not associated with lower SVR12 rates (lower 95% confidence bound > 60%):

  • Viral factors: genotype 1 subtype, baseline viral load
  • Host factors: prior pegIFN/RBV response, gender, race, ethnicity, age, birth year (1945 – 1965), IL28B allele, baseline body mass index, history of depression or bipolar disorder, fibrosis stage

In addition, subjects who underwent ribavirin dose modifications did not have lower SVR12 rates.

PEARL-II (M13-389) – Genotype 1b, Treatment-Experienced

PEARL-II was a randomised, global multicentre, open-label trial conducted in 180 adults with chronic genotype 1b hepatitis C virus infection without cirrhosis who did not achieve SVR with prior treatment with pegIFN/RBV. Subjects were randomised, in a 1:1 ratio, to receive VIEKIRA PAK or VIEKIRA PAK-RBV for 12 weeks of treatment.

Treated subjects (N=179) had a median age of 57 years (range: 26 to 70); 35.2% were prior pegIFN/RBV null responders; 28.5% were prior pegIFN/RBV partial responders, and 36.3% were prior pegIFN/RBV relapsers; 70.9% were born between 1945 – 1965; 54.2% were male; 3.9% were Black; 1.7% were Hispanic or Latino; 21.8% had a body mass index of at least 30 kg/m2; 12.8% had a history of depression or bipolar disorder; 90.5% had IL28B non-CC genotype; 87.7% had baseline HCV RNA levels of at least 800,000 IU/mL; 17.9% had portal fibrosis (F2) and 14.0% had bridging fibrosis (F3).

Table 9 shows the SVR12 rates for genotype 1b-infected, treatment-experienced subjects who received VIEKIRA PAK or VIEKIRA PAK-RBV for 12 weeks in PEARL II. In this study, VIEKIRA PAK had a similar SVR12 rate (100%) compared to VIEKIRA PAK-RBV (97.7%).

Table 9: SVR12 for Genotype 1b-infected Treatment-Experienced Subjects in PEARL II
VIEKIRA PAK-RBV for 12
weeks
VIEKIRA PAK for 12 weeks
  n/N % 95% CI n/N % 95% CI
Overall SVR12 86/88 97,7 94.6, 100.0 91/91 100 95.9, 100.0
Prior pegIFN/RBV null responder 30/31 96,8 90.6, 100.0 32/32 100 89.3, 100.0
Prior pegIFN/RBV partial  responder 24/25 96,0 88.3, 100.0 26/26 100 87.1, 100.0
Prior pegIFN/RBV relapser 32/32 100 89.3, 100.0 33/33 100 89.6, 100.0
Outcome for subjects without SVR12            
On-treatment VFa 0/88 0   0/91 0  
Relapseb 0/88 0   0/91 0  
Otherc 2/88 2,3   0/91 0  
CI = confidence interval, VF = virologic failure
a.   On-treatment VF was defined as confirmed HCV ≥ 25 IU/mL after HCV RNA < 25 IU/mL during treatment, confirmed 1 log10  IU/mL increase in HCV RNA from nadir, or HCV RNA persistently ≥ 25 IU/mL with at least 6 weeks of treatment.
b.   Relapse was defined as confirmed HCV RNA greater than 25 IU/mL post-treatment before or during SVR12 window  among  subjects  with  HCV  RNA  <  25  IU/mL  at  last observation  during  at  least  11  weeks  of treatment.
c.   Other includes subjects not achieving SVR12 but not experiencing on-treatment VF or relapse (e.g. missing HCV RNA values in the SVR12 window).

In the primary efficacy analysis, VIEKIRA PAK and VIEKIRA PAK-RBV demonstrated superiority to the historical control SVR rate of 69% {95% CI of 62%, 75%} (based upon telaprevir plus pegIFN/RBV) for subjects with genotype 1b HCV infection who were treatment- experienced without cirrhosis. Refer to the telaprevir prescribing information.

Based on subgroup analyses, the following baseline factors were not associated with lower SVR12 rates (lower 95% confidence bound > 64%):

  • Viral factors: baseline viral load
  • Host factors: prior pegIFN/RBV response, gender, race, ethnicity, age, birth year (1945 – 1965), IL28B allele, baseline body mass index, history of depression or bipolar disorder, fibrosis stage

In addition, subjects who underwent ribavirin dose modifications did not have lower SVR12 rates.

Clinical Trial in Subjects with Cirrhosis

TURQUOISE-II (M13-099) – Genotype 1, Treatment-naïve or treatment-experienced patients with cirrhosis

TURQUOISE-II was a randomised, global multicentre, open-label trial conducted exclusively in 380 genotype 1-infected subjects with cirrhosis (Child-Pugh A) who were either treatment-naïve or did not achieve SVR with prior treatment with pegIFN/RBV. VIEKIRA PAK-RBV was administered for either 12 or 24 weeks of treatment.

Treated subjects (N=380) had a median age of 58 years (range: 21 to 71); 42.1% were treatment-naïve, 36.1% were prior pegIFN/RBV null responders; 8.2% were prior pegIFN/RBV partial responders, 13.7% were prior pegIFN/RBV relapsers; 85.5% were born between 1945 – 1965; 70.3% were male; 3.2% were Black; 11.8% were Hispanic or Latino; 28.4% had a body mass index of at least 30 kg/m2; 14.7% had platelet counts of < 90 x 109/L; 11.3% had albumin (< 35 g/L); 86.1% had baseline HCV RNA levels of at least 800,000 IU/mL; 81.8% had IL28B non-CC genotype; 24.7% had a history of depression or bipolar disorder; 68.7% had HCV genotype 1a infection, 31.3% had HCV genotype 1b infection.

Table 10 shows the SVR12 rates for genotype 1-infected subjects with cirrhosis who were treatment-naïve or previously treated with pegIFN/RBV.

Table 10: SVR12 for Genotype 1-Infected Subjects with Cirrhosis who were Treatment-Naïve or Previously Treated with pegIFN/RBV
Treatment Outcome VIEKIRA PAK-RBV
  12 Weeks     24 Weeks  
n/N % CIa n/N % CIa
Overall SVR12 191/208 91,8 87.6, 96.1 166/1
72
96,5 93.4, 99.6
HCV Genotype 1a 124/140 88,6 83.3, 93.8 115/1
21
95,0 91.2, 98.9
Treatment naïve 59/64 92,2   53/56 94,6  
Prior pegIFN/RBV null responders 40/50 80,0   39/42 92,9  
Prior pegIFN/RBV partial responders 11/11 100   10/10 100  
Prior pegIFN/RBV Prior relapsers 14/15 93,3   13/13 100  
HCV Genotype 1b 67/68 98,5 95.7, 100 51/51 100 93.0, 100
Treatment naïve 22/22 100   18/18 100  
Prior pegIFN/RBV null responders 25/25 100   20/20 100  
Prior pegIFN/RBV partial responders 6/7 85,7   3/3 100  
Prior pegIFN/RBV Prior relapsers 14/14 100   10/10 100  
Outcome for subjects without SVR12            
On-treatment VFb 1/208 0,5   3/172 1,7  
Relapsec 12/203 5,9   1/164 0,6  
Otherd 4/208 1,9   2/172 1,2  
CI = confidence interval, VF = virologic failure, NA = data not yet available
a.     97.5% confidence intervals are used for the primary efficacy endpoints (overall SVR12 rate); 95% confidence intervals are used for additional efficacy endpoints (SVR12 rates in HCV genotype 1a and 1b subjects).
b.    On-treatment VF was defined as confirmed HCV ≥ 25 IU/mL after HCV RNA < 25 IU/mL during treatment, confirmed 1 log10  IU/mL increase in HCV RNA from nadir, or HCV RNA persistently ≥ 25 IU/mL with at least 6 weeks of treatment.
c.     Relapse was defined as confirmed HCV RNA ≥ 25 IU/mL post-treatment before or during SVR12 window among subjects with HCV RNA < 25 IU/mL at last observation during at least 11 or 22 weeks of treatment, for subjects assigned to 12 or 24 weeks of treatment, respectively.
d.    Other includes subjects not achieving SVR12 but not experiencing on-treatment VF or relapse (e.g. missing HCV RNA values in the SVR12 window).

In the primary efficacy analysis, VIEKIRA PAK-RBV administered for 12 or 24 weeks demonstrated superiority to the historical control SVR rate of 47% {95% CI of 41%, 54%} (based upon telaprevir plus pegIFN/RBV) for subjects with genotype 1 HCV infection with cirrhosis that were treatment-naïve or previously treated with pegIFN/RBV. Refer to the telaprevir prescribing information.

Based on subgroup analyses, the following baseline factors were not associated with lower SVR12 rates (lower 95% confidence bound > 43%):

  • Viral factors: genotype 1 subtype, baseline viral load
  • Host factors: prior pegIFN/RBV response, gender, ethnicity, age, birth year (1945 – 1965), IL28B allele, baseline body mass index, history of depression or bipolar disorder, fibrosis stage, baseline platelet count, baseline albumin

In addition, subjects who underwent ribavirin dose modifications did not have lower SVR12 rates.

Indications

VIEKIRA PAK-RBV is indicated for the treatment of genotype 1 chronic hepatitis C infection, including patients with compensated cirrhosis. Duration of therapy and addition of ribavirin are dependent on patient population (see DOSAGE AND ADMINISTRATION, PRECAUTIONS, CLINICAL TRIALS).

Contraindications

Hypersensitivity to components of VIEKIRA PAK-RBV, or to any of the excipients.

Patients with severe hepatic impairment (Child-Pugh C).

Use of ethinylestradiol-containing medicinal products such as those contained in most combined oral contraceptives or contraceptive vaginal rings.

Drugs that are highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events.

Drugs that are moderate or strong inducers of CYP3A and strong inducers of CYP2C8 and may lead to reduced efficacy of VIEKIRA PAK-RBV.

Drugs that are strong inhibitors of CYP2C8 and therefore may increase dasabuvir plasma concentrations and the risk of QT prolongation.

The following drugs are contraindicated with VIEKIRA PAK-RBV.

Table 11 Drugs that are Contraindicated with VIEKIRA PAK-RBV
Drug Class Drug(s) within Class that are Contraindicated Clinical Comments
Alpha1- adrenoreceptor antagonist Alfuzosin HCl Potential for hypotension.
Antiarrhythmics Amiodarone, quinidine Potential for cardiac arrhythmias.
Anticonvulsants Carbamazepine, phenytoin, phenobarbital Ombitasvir, paritaprevir, ritonavir and dasabuvir exposures may decrease leading to a potential loss of therapeutic activity of VIEKIRA PAK-RBV.
Antihistamines (for systemic use) Astemizole, terfenadine Potential for cardiac arrhythmias.
GI motility agent Cisapride Potential for cardiac arrhythmias.
Antigout medications Colchicine (in patients with renal or hepatic impairment) Potential for serious and/or life-threatening reactions in patients with renal and/or hepatic impairment.
Antihyperlipidemic agent Gemfibrozil Increase in dasabuvir exposures by 10-fold which may increase the risk of QT prolongation.
Antimycobacterial Rifampicin Ombitasvir, paritaprevir, ritonavir and dasabuvir exposures may decrease leading to a potential loss of therapeutic activity of VIEKIRA PAK-RBV.
Antipsychotic Blonanserin No information on potential effects is currently available
Ergot derivatives Ergotamine, dihydroergotamine, ergonovine, methylergonovine Acute ergot toxicity characterised by vasospasm and tissue ischemia has been associated with
co-administration of ritonavir and ergonovirgotamine, dihydroergotamine, or methylergonovine.

Ethinyl estradiol- containing products Ethinyl estradiol- containing medications such as combined oral contraceptives Potential for ALT elevations (see PRECAUTIONS).
Herbal Product St. John’s Wort
(Hypericum perforatum)
Ombitasvir, paritaprevir, ritonavir and dasabuvir exposures may decrease leading to a potential loss of therapeutic activity of VIEKIRA PAK-RBV.
HMG-CoA Reductase Inhibitors Lovastatin, simvastatin Potential for myopathy including rhabdomyolysis.
Long Acting Beta- Adrenoceptor agonist Salmeterol The combination may result in increased risk of cardiovascular adverse events associated with salmeterol, including QT prolongation,
palpitations inus tachycardia.

Neuroleptics Pimozide Potential for cardiac arrhythmias.
Non-nucleoside reverse transcriptase inhibitor Efavirenz Co-administration of efavirenz based regimens with paritaprevir, ritonavir plus dasabuvir was poorly tolerated and resulted in liver enzyme elevations.
Phosphodiesterase-5 (PDE5) inhibitor Sildenafil when dosed for the treatment of pulmonary arterial hypertension (PAH) There is increased potential for sildenafil- associated adverse events such as visual disturbances, hypotension, priapism, and syncope.
Platelet aggregation inhibitors excluding heparin Ticagrelor Increased potential for ticagrelor associated adverse events.
Sedatives/hypnotics Triazolam
Orally administered midazolam
Triazolam and orally administered midazolam are extensively metabolised by CYP3A4. Co- administration of triazolam or orally administered midazolam wIEKIRA PAK-RBV may cause large increases in the concentration of these benzodiazepines. The potential exists for serious and/or life threatening events such as prolonged or increased sedation or respiratory depression.

Steroid antibacterials Fusidic acid Increased potential for fusidic acid associated adverse events.
Anticancer agents Mitotane Enzalutamide Increased potential for mitotane and enzalutamide associated adverse events.

The following contraindications are specific to ribavirin:

  • Pregnant women (see PRECAUTIONS). Ribavirin must not be initiated until a report of a negative pregnancy test has been obtained immediately prior to initiation of therapy.
  • Men whose female partners are pregnant (see PRECAUTIONS).
  • A history of severe, pre-existing cardiac disease, including unstable or uncontrolled cardiac disease, in the previous six months.
  • Severe hepatic dysfunction or decompensated liver disease.
  • Haemoglobinopathies (e.g. thalassaemia, sickle-cell anaemia)
  • Breast-feeding

Precautions

VIEKIRA PAK-RBV efficacy has not been studied in patients who have previously failed therapy with a treatment regimen that includes VIEKIRA PAK-RBV or other direct-acting antiviral agents.

Risk of Hepatic Decompensation and Hepatic Failure in Patients with Cirrhosis

Hepatic decompensation and hepatic failure, including liver transplantation or fatal outcomes, have been reported from postmarketing sources in patients treated with paritaprevir/ritonavir/ombitasvir with and without dasabuvir and with and without ribavirin. Most patients with these severe outcomes had evidence of advanced or decompensated cirrhosis prior to initiating therapy. Reported cases typically occurred within one to four weeks of initiating therapy and were characterised by the acute onset of rising direct serum bilirubin levels without ALT elevations in association with clinical signs and symptoms of hepatic decompensation. Because these events are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Paritaprevir/ritonavir/ombitasvir with or without dasabuvir is not recommended in patients with moderate hepatic impairment (Child-Pugh B). A decision to initiate treatment in patients with Child-Pugh B should be guided by assessment of the potential benefits and risks for the individual.

Paritaprevir/ritonavir/ombitasvir with or without dasabuvir is contraindicated in patients with severe hepatic impairment (Child-Pugh C).

For patients with cirrhosis:

  • Monitor for clinical signs and symptoms of hepatic decompensation (such as ascites, hepatic encephalopathy, variceal hemorrhage). 
  • Hepatic laboratory testing including direct bilirubin levels should be performed at baseline, during the first 4 weeks of starting treatment and as clinically indicated thereafter.
  • Discontinue treatment in patients who develop evidence of hepatic decompensation.

ALT Elevations

During clinical trials with VIEKIRA PAK with or without ribavirin, transient, asymptomatic elevations of alanine transaminase (ALT) to greater than 5 times the upper limit of normal (ULN) occurred in approximately 1% of all subjects (see PRECAUTIONS). These ALT elevations were significantly more frequent in female subjects who were using ethinyl estradiol-containing medications such as combined oral contraceptives, contraceptive patches, or contraceptive vaginal rings (see CONTRAINDICATIONS). ALT elevations typically occurred during the first 4 weeks of treatment and declined within approximately two weeks of onset with continued dosing of VIEKIRA PAK with or without ribavirin.

Ethinyl estradiol-containing medications must be discontinued prior to starting therapy with VIEKIRA PAK-RBV (see CONTRAINDICATIONS). Alternative contraceptive agents or methods of contraception (e.g., progestin only contraception or non-hormonal methods) are recommended during VIEKIRA PAK-RBV therapy. Ethinyl estradiol-containing medications can be restarted approximately 2 weeks following completion of treatment with VIEKIRA PAK-RBV.

Subjects using estrogens other than ethinyl estradiol, such as estradiol and conjugated estrogens used in hormone replacement therapy had a rate of ALT elevation similar to those not receiving any estrogens (1%). No additional monitoring of ALT is required outside of local recommendations and routine clinical practice guidelines.

If ALT is found to be elevated above baseline levels, it should be monitored closely.

  • Patients should be instructed to consult their health care professional without delay if they have onset of fatigue, weakness, lack of appetite, nausea and vomiting, jaundice or discoloured urine or faeces (see Serum Bilirubin Elevations under PRECAUTIONS).
  • Discontinue VIEKIRA PAK-RBV if ALT elevation is accompanied by signs or symptoms of liver inflammation or increasing conjugated bilirubin, alkaline phosphatase, or international normalised ratio (INR).

Co-administration with Drugs Metabolised by CYP3A

Also refer to the CONTRAINDICATIONS, INTERACTIONS WITH OTHER MEDICINES, Table 13 and PHARMACOKINETICS-Implications for Drug Interactions.

Use with Fluticasone (glucocorticoids metabolised by CYP3A)

Use caution when administering VIEKIRA PAK-RBV with fluticasone or other glucocorticoids that are metabolised by CYP3A4. Concomitant use of inhaled glucocorticoids metabolised with CYP3A can increase systemic exposures of the glucocorticoids and cases of Cushing’s syndrome and subsequent adrenal suppression have been reported with ritonavir-containing regimens. Concomitant use of VIEKIRA PAK-RBV and glucocorticoids, particularly long-term use, should only be initiated if the potential benefit of treatment outweighs the risk of systemic corticosteroid effects.

Use with Quetiapine

The use of VIEKIRA PAK-RBV with quetiapine is not recommended due to increases in quetiapine exposure. If co-administration is necessary, reduce the quetiapine dose to 1/6th of the current dose and monitor for quetiapine-associated adverse reactions. Refer to the quetiapine prescribing information for the recommendations on adverse reaction monitoring.

Use with colchicine

A reduction in colchicine dosage or an interruption of colchicine treatment is recommended in patients with normal renal or hepatic function if treatment with VIEKIRA PAK-RBV is required (Table 13). In patients with renal or hepatic impairment, use of colchicine with VIEKIRA PAK-RBV is contraindicated (see CONTRAINDICATIONS).

Use with statins

Simvastatin and lovastatin are contraindicated (see CONTRAINDICATIONS)

Atorvastatin, Pitavastatin and fluvastatin

The interactions between atorvastatin, pitavastatin and fluvastatin and VIEKIRA PAK-RBV have not been investigated. Theoretically, VIEKIRA PAK-RBV is expected to increase the exposure to atorvastatin, pitavastatin and fluvastatin. A temporary suspension of atorvastatin, pitavastatin, fluvastatin is recommended for the duration of treatment with VIEKIRA PAK-RBV. If statin treatment is required during the treatment period, a switch to a reduced dose of pravastatin or rosuvastatin is possible (see Table 13).

Hepatic Impairment

No dose adjustment of VIEKIRA PAK-RBV is required in patients with mild hepatic impairment (Child-Pugh A).. VIEKIRA PAK-RBV is not recommended in patients with moderate hepatic impairment (Child-Pugh B). A decision to initiate treatment in patients with Child-Pugh B should be guided by assessment of the potential benefits and risks for the individual. VIEKIRA PAK-RBV is contraindicated in patients with severe hepatic impairment (Child-Pugh C) (see CONTRAINDICATIONS and Pharmacokinetics).

Treatment of Patients with Other HCV Genotypes

The safety and efficacy of VIEKIRA PAK-RBV has not been established in patients with HCV genotypes other than genotype 1.

Haemolysis and cardiovascular system

Although ribavirin has no direct cardiovascular effects, anaemia associated with ribavirin may result in deterioration of cardiac function, or exacerbation of the symptoms of coronary disease, or both. Thus, ribavirin must be administered with caution to patients with pre-existing cardiac disease. Cardiac status must be assessed before start of therapy and monitored clinically during therapy; if any deterioration occurs, therapy should be discontinued (see DOSAGE AND ADMINISTRATION). Patients with a history of congestive heart failure, myocardial infarction, and/or previous or current arrhythmic disorders must be closely monitored. It is recommended that those patients who have pre-existing cardiac abnormalities have electrocardiograms taken prior to and during the course of treatment. Cardiac arrhythmias (primarily supraventricular) usually respond to conventional therapy but may require discontinuation of therapy. There are no data in children or adolescents with a history of cardiac disease.

Gout

Uric acid may increase with ribavirin due to haemolysis and therefore patients predisposed to gout should be carefully monitored.

Acute Hypersensitivity

If an acute hypersensitivity reaction to ribavirin (e.g. urticaria, angioedema, bronchoconstriction, and anaphylaxis) develops, ribavirin must be discontinued immediately and appropriate medical therapy instituted. Transient rashes do not necessitate interruption of treatment.

Renal Impairment

The pharmacokinetics of ribavirin are altered in patients with renal dysfunction due to reduction of apparent clearance in these patients. Therefore, it is recommended that renal function be evaluated in all patients prior to initiation of ribavirin, preferably by estimating the patient's creatinine clearance. Substantial increases in ribavirin plasma concentrations are seen at the recommended dosing regimen in patients with serum creatinine >2 mg/dl or with creatinine clearance <50 mL/minute. The dose of ribavirin should be reduced in patients with creatinine clearance less than or equal to 50 mL/min (see DOSAGE AND ADMINISTRATION). Haemoglobin concentrations should be monitored intensively during treatment in patients with renal dysfunction and corrective actions taken as necessary (see DOSAGE AND ADMINISTRATION).

Effects on Fertility

Ribavirin

No reproductive studies have been conducted with ribavirin combination therapy. In animal studies, ribavirin produced changes in sperm at doses below the clinical dose. Ribavirin has induced testicular toxicity in mice and rats. In a three to six month gavage study in mice, ribavirin significantly increased the percentage of morphologically abnormal sperm at 15 mg/kg/day (approximately 0.1 times the clinical exposure (AUC) at the maximum recommended dose) and above (see PRECAUTIONS), and reduced spermatid and sperm concentrations at 35 mg/kg/day and above. After cessation of dosing, mice almost completely recovered from testicular toxicity within one to two spermatogenesis cycles i.e. approximately 1.5 to 3 months. In rats, gavage doses of 160 mg/kg/day (approximately 0.4 times the clinical exposure (AUC) at the maximum recommended dose) for nine weeks reduced spermatid counts and lowered epididymal weights, and testicular tubular atrophy occurred after administration of 160 mg/kg/day in the diet for 30 days. Testicular toxicity was not observed in other rat studies at gavage doses of up to 200 mg/kg/day for 90 days, or at 90 mg/kg/day in the diet for 12 months.

Paritaprevir/ritonavir

Paritaprevir/ritonavir had no effects on embryofoetal viability or on fertility when evaluated in rats up to the highest dose of 300/30 mg/kg/day. Paritaprevir and ritonavir AUC exposures at this dosage were approximately 2 and 3-fold the exposure in humans at the recommended clinical dose.

Ombitasvir

Ombitasvir had no effects on embryofoetal viability or on fertility when evaluated in mice up to the highest dose of 200 mg/kg/day. Ombitasvir AUC exposures at this dosage were approximately 23-fold (female) or 29-fold (male) the exposure in humans at the recommended clinical dose.

Dasabuvir

Dasabuvir had no effects on embryofoetal viability or on fertility when evaluated in rats up to the highest dosage of 800 mg/kg/day. Dasabuvir AUC exposures at this dosage were approximately 16-fold the exposure in humans at the recommended clinical dose.

Use in Pregnancy

Pregnancy Category X: VIEKIRA PAK-RBV

There are no studies in pregnant women with paritaprevir/ritonavir, ombitasvir and dasabuvir in combination with ribavirin. Animal teratology studies have not been conducted with paritaprevir/ritonavir, ombitasvir and dasabuvir in combination with ribavirin; however, ribavirin may cause birth defects and/or death of the exposed foetus. (see CONTRAINDICATIONS).

Extreme care must be taken to avoid pregnancy in female patients and in female partners of male patients as significant teratogenic and/or embryocidal effects have been demonstrated in all animal species exposed to ribavirin. Ribavirin should not be started unless a report of a negative pregnancy test has been obtained immediately prior to initiation of therapy. Female patients of childbearing potential and their male partners as well as male patients and their female partners must use at least two effective forms of contraception during treatment and for at least 6 months (24 weeks) post-therapy, based on a multiple dose ribavirin half-life of 12 days.

See additional information on specific hormonal contraceptives below and in PRECAUTIONS and Interactions with other medicines. Routine monthly pregnancy tests must be performed during this time.

Ribavirin has demonstrated significant teratogenic and/or embryocidal potential in all animal species in which adequate studies have been conducted. In rats and rabbits, a gavage dose of 1 mg/kg/day, and in hamsters a dose of 2.5 mg/kg/day, administered during the period of organogenesis, was associated with embryotoxic or teratogenic effects. Malformations of the skull, palate, eye, jaw, limbs, skeleton and gastrointestinal tract were noted.

Based on postmarketing surveillance, there are reports of congenital abnormalities, childhood disorders and miscarriages in female patients directly exposed to ribavirin during pregnancy and those female patients whose male partners were exposed to ribavirin therapy. The relationship of these outcomes to ribavirin exposure is unknown.

No effects on embryofoetal development have been noted in studies in animals with paritaprevir/ritonavir (in combination), ombitasvir and its major inactive human metabolites (M29, M36) or dasabuvir. For paritaprevir/ritonavir, the highest doses tested produced exposures equal to 98-fold (mouse) or 8-fold (rat) (for paritaprevir and 8-fold (mouse) or 3-fold (rat) for ritonavir) the exposures in humans at the recommended clinical doses. For ombitasvir, the highest dose tested produced exposures equal to 28-fold (mouse) or 4-fold (rabbit) the exposures in humans at therecommended clinical dose. tested produced exposures recommended clinical dose. The highest doses of the major, inactive human metabolites similarly approximately 26 times higher in mice than in humans at the

Developmental toxicity has been observed in embryofoetal development studies with ritonavir alone. In rats, early resorptions, decreased foetal body weight and ossification delays and developmental variations occurred at a maternally toxic dosage of 75 mg/kg/day (5-fold the exposure in humans at the recommended clinical dose). A slight increase in the incidence of cryptorchidism was also noted in rats given 35 mg/kg/day (4-fold the exposure in humans at the recommended clinical dose). Developmental toxicity observed in rabbits (resorptions, decreased litter size and decreased foetal weights) also occurred at a maternally toxic dosage of 110 mg/kg/day. For dasabuvir, the highest dose tested produced exposures equal to 24-fold (rat) or 6-fold (rabbit) the exposures in humans at the recommended clinical dose. Developmental effects have not been identified in humans exposed to ritonavir during pregnancy nor has there been an association with cryptorchidism.

Use in Lactation

It is not known whether paritaprevir/ritonavir, ombitasvir, dasabuvir and their metabolites or ribavirin are excreted in human breast milk. Paritaprevir and its hydrolysis product M13, unchanged ombitasvir and dasabuvir were the predominant components observed in the milk of lactating rats, without effect on nursing pups.

Because of the potential for adverse reactions in nursing infants, breast feeding must be discontinued prior to initiation of treatment.

Paediatric Use

Safety and effectiveness of VIEKIRA PAK-RBV in children less than 18 years of age have not been established.

Use in the Elderly

No dose adjustment of VIEKIRA PAK-RBV is warranted in elderly patients. In Phase 3 clinical trials, 8.5% (174/2053) of subjects were age 65 or over. No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger subjects.

Specific pharmacokinetic evaluations of ribavirin for elderly subjects have not been performed. The risk of toxic reactions to this drug may be greater in patients with impaired renal function. The dose of ribavirin should be reduced in patients with creatinine clearance less than or equal to 50 mL/min. (see DOSAGE AND ADMINISTRATION).

The safety and effectiveness of VIEKIRA PAK-RBV has not been established in patients aged 70 years or over.

Genotoxicity

Paritaprevir

Paritaprevir was positive in an in vitro human chromosome aberration test. Paritaprevir was negative in a bacterial mutation assay, and in two in vivo genetic toxicology assays (rat bone marrow micronucleus and rat liver Comet tests).

Ombitasvir

Ombitasvir and its major inactive human metabolites (M29, M36) were not genotoxic in a battery of in vitro or in vivo assays, including bacterial mutagenicity, chromosome aberration using human peripheral blood lymphocytes and in vivo mouse micronucleus assays.

Dasabuvir

Dasabuvir was not genotoxic in a battery of in vitro or in vivo assays, including bacterial mutagenicity, chromosome aberration using human peripheral blood lymphocytes and in vivo rat micronucleus assays.

Ritonavir

Ritonavir showed no mutagenic potential in a series of assays for gene mutations (S. typhimurium, E. coli and mouse lymphoma cells) and chromosomal damage (mouse micronucleus assay in-vivo and human lymphocytes in-vitro).

Ribavirin

Ribavirin was positive in vitro in the Balb/3T3 cell transformation assay. It was equivocal in the mouse lymphoma (L5178Y) assay and was positive in vivo in a mouse micronucleus assay. Ribavirin was negative in a range of other assays for gene mutations (Salmonella typhimurium, host-mediated assay) and chromosomal damage (dominant lethal assay in rats)

Carcinogenicity

Paritaprevir/ritonavir was not carcinogenic in a 6-month transgenic mouse study up to the highest dosage tested (300/30 mg/kg/day), resulting in paritaprevir and ritonavir AUC exposures approximately 38 and 5-fold higher, respectively than those in humans at the recommended dose of 150/50 mg. Similarly, paritaprevir/ritonavir was not carcinogenic in a 2-year rat study up to the highest dosage tested (300/30 mg/kg/day), resulting in paritaprevir/ritonavir AUC exposures approximately 8/5-fold higher than those in humans at 150/50 mg.

Two-year carcinogenicity studies have been conducted in rodents with ritonavir alone at dietary levels of 50, 100 and 200 mg/kg/day in mice, and 7, 15 and 30 mg/kg/day in rats. In male mice there was a dose-dependent increase in the incidence of hepatocellular adenomas, and adenomas and carcinomas combined, both reaching statistical significance only at the high-dose. In female mice there were small, statistically significant increases in these tumour incidences only at the high-dose. In rats, there were no tumorigenic effects.

Ombitasvir was not carcinogenic in a 6-month transgenic mouse study up to the highest dosage tested (150 mg/kg/day), resulting in ombitasvir AUC exposures approximately 26-fold higher than those in humans at the recommended clinical dose of 25 mg. The carcinogenicity study of ombitasvir in rats is ongoing.

Dasabuvir was not carcinogenic in a 6-month transgenic mouse study up to the highest dosage tested (2000 mg per kg per day), resulting in dasabuvir AUC exposures approximately 19-fold higher than those in humans at the recommended dose of 500 mg (250 mg twice daily). The carcinogenicity study of dasabuvir in rats is ongoing.

Ribavirin is mutagenic in some in vivo and in vitro genotoxicity assays. Conventional carcinogenicity rodent studies with low exposures compared to human exposure under therapeutic conditions did not reveal tumorigenicity of ribavirin. In addition, in a 26-week carcinogenicity study using the heterozygous p53 (+/-) mouse model, ribavirin did not produce tumours at the maximally tolerated dose of 300 mg/kg/day.

Effect on Laboratory Tests

Changes in selected laboratory parameters are described in Table 12. A side-by-side tabulation is provided to simplify presentation; direct comparisons should not be made across trials that differ in study design.

Table 12: Selected Treatment Emergent Laboratory Abnormalities
Laboratory Parameters SAPPHIRE I and II PEARL II, III and IV TURQUOISE II
(subjects with cirrhosis)
VIEKIRA PAK
+ RBV
12 Weeks
N = 770 n (%)
Placebo 12 Weeks
N = 255 n (%)
VIEKIRA PAK + RBV
12 Weeks
N = 401 n (%)
VIEKIRA PAK 12
Weeks N = 509 n (%)
VIEKIRA PAK + RBV
12 or 24 Weeks
N = 380 n (%)
ALT
> 5-20 × ULN* (Grade 3) 6/765 (0.8%) 10/254 (3.9%) 3/401 (0.7%) 1/509 (0.2%) 4/380 (1.1%)
> 20 × ULN (Grade 4) 3/765 (0.4%) 0 0 0 2/380 (0.5%)
Haemoglobin
< 10-8 g/dL (Grade 2) 41/765 (5.4%) 0 23/401 (5.7%) 0 30/380 (7.9%)
< 8-6.5 g/dL (Grade 3) 1/765 (0.1%) 0 2/401 (0.5%) 0 3/380 (0.8%)
< 6.5 g/dL (Grade 4) 0 0 0 0 1/380 (0.3%)
Total Bilirubin
> 3-10 × ULN (Grade 3) 19/765 (2.5%) 0 23/401 (5.7%) 2/509 (0.4%) 37/380 (9.7%)
> 10 × ULN (Grade 4) 1/765 (0.1%) 0 0 0 0
*ULN: Upper Limit of Normal according to testing laboratory.

Serum ALT elevations

During clinical trials with VIEKIRA PAK and VIEKIRA PAK-RBV, less than 1% of subjects who were not on systemic ethinyl estradiol-containing medications experienced transient serum ALT levels greater than 5 times the upper limit of normal (ULN) after starting treatment. These elevations were asymptomatic, generally occurred during the first 4 weeks of treatment and resolved with ongoing therapy. Elevations in ALT were generally not associated with bilirubin elevations. Cirrhosis was not a risk factor for elevated ALT (see PRECAUTIONS).

Serum Bilirubin Elevations

Transient elevations in bilirubin (predominantly indirect) were observed in subjects receiving VIEKIRA PAK-RBV, related to the inhibition of the bilirubin transporters OATP1B1/1B3 by paritaprevir and ribavirin-induced haemolysis. Bilirubin elevations occurred after initiation of treatment, peaked by study Week 1, and generally resolved with ongoing therapy. Bilirubin elevations were not associated with aminotransferase elevations. The frequency of indirect bilirubin elevations was lower among subjects who did not receive ribavirin.

Interactions with Other Medicines

Also refer to the CONTRAINDICATIONS, PRECAUTIONS INTERACTIONS WITH OTHER MEDICINES SECTION, Table 13 and PHARMACOKINETICS-Implications for Drug Interactions sections.

Recommendations for co-administration of VIEKIRA PAK-RBV for a number of medicinal products are provided in Table 13.

If a patient is already taking medicinal product(s) or initiating a medicinal product while receiving VIEKIRA PAK-RBV for which potential for drug interaction is expected, dose adjustment of the concomitant medicinal product(s) or appropriate clinical monitoring should be considered (Table 13).

A change of 0.5- to 2.0-fold in the exposures (Cmax and AUC) of paritaprevir, ombitasvir and dasabuvir is not considered clinically relevant and does not require dose adjustment for VIEKIRA PAK-RBV.

If dose adjustments of concomitant medicinal products are made due to treatment with VIEKIRA PAK-RBV, doses should be re-adjusted after administration of VIEKIRA PAK-RBV is completed.

Table 13 provides the Least Squares Means Ratio (90% Confidence Interval) effect on concentration of VIEKIRA PAK-RBV and concomitant medicinal products. Dose adjustment is not required for VIEKIRA PAK-RBV when administered with the concomitant medications listed in Table 13 unless otherwise noted.

Table 13: Interactions between VIEKIRA PAK and other medicinal products
Drug Class
Drug Name
Effect Clinical Comment
Aminosalicylate
Sulfasalazine* ↑ sulfasalazine Mechanism: BCRP inhibition by paritaprevir, ritonavir and dasabuvir. Caution should be used when sulfasalazine is co-administered with VIEKIRA PAK-RBV.
Analgesic
paracetamol No dose adjustments are required when co-administering with VIEKIRA PAK-RBV.
Angiotensin receptor blocker
Valsartan* Losartan * candesartan * ↑ angiotensin receptor blockers Mechanism: OATP1B inhibition by paritaprevir.
Decrease the dose of the angiotensin receptor blockers and monitor patients for signs and symptoms of hypotension and/or worsening renal function. .
Antiarrhythmics
Digoxin Cmax AUC Cmin Mechanism: P-gp inhibition by paritaprevir, ritonavir and dasabuvir. While no dose adjustment is necessary for digoxin, appropriate monitoring of serum digoxin levels is recommended.
↔ digoxin 1.15
(1.04-1.27)
1.16
(1.09-1.23)
1.01
(0.97-1.05)
↔ ombitasvir 1.03
(0.97-1.10)
1.00
(0.98-1.03)
0.99
(0.96-1.02)
↔ paritaprevir 0.92
(0.80-1.06)
0.94
(0.81-1.08)
0.92
(0.82-1.02)
↔ dasabuvir 0.99
(0.92-1.07)
0.97
(0.91-1.02)
0.99
(0.92-1.07)
bepridil*, lidocaine (systemic) *, disopyramide*, propafenone* ↑ antiarrhythmic agents
Decrease in the dose and therapeutic concentration monitoring (if available) is recommended for the antiarrhythmic agents when co-administered with VIEKIRA PAK- RBV.
Antibiotics
Erythromycin* ↑ erythromycin Mechanism: CYP3A4/P-gp inhibition by paritaprevir, ritonavir and dasabuvir.
Caution is advised when erythromycin is administered with Viekira Pak-RBV.
Sulfamethoxazole No dose adjustments are required when co-administering with VIEKIRA PAK-RBV.
Trimethoprim No dose adjustments are required when co-administering with VIEKIRA PAK-RBV.
Anticancer agents
Imatinib* ↑ imatinib Mechanism: BCRP inhibition by paritaprevir, ritonavir and dasabuvir. Clinical monitoring and lower doses of imatinib are recommended.
Anticoagulants
Warfarin
5 mg single dose
Cmax AUC Cmin While no dose adjustment is necessary for warfarin, appropriate monitoring of international normalised ratio (INR) is recommended.

R-warfarin
1.05
(0.95-1.17)
0.88
(0.81-0.95)
0.94
(0.84-1.05)

S-warfarin
0.96
(0.85-1.08)
0.88
(0.81-0.96)
0.95
(0.88-1.02)
↔ ombitasvir 0.94
(0.89-1.00)
0.96
(0.93-1.00)
0.98
(0.95-1.02)
↔ paritaprevir 0.98
(0.82-1.18)
1.07
(0.89-1.27)
0.96
(0.85-1.09)
↔ dasabuvir 0.97
(0.89-1.06)
0.98
(0.91-1.06)
1.03
(0.94-1.13)
Dabigatran* etexilate ↑ dabigatran Mechanism: Intestinal P-gp inhibition by paritaprevir, dasabuvir and ritonavir. VIEKIRA PAK-RBV may increase the plasma concentrations of dabigatran etexilate. Use with caution.
S-mephenytoin* ↓ S-mephenytoin Mechanism: CYP2C19 induction by ritonavir.
Clinical monitoring and dose adjustment maybe needed for s- mephenytoin.
Antidepressants
Escitalopram
10 mg single dose
Cmax AUC Cmin No dose adjustment is necessary for escitalopram.
↔ es- citalopram 1.00
(0.96-1.05)
0.87
(0.80-0.95)
NA
↑ S- Desmethyl citalopram 1.15
(1.10-1.21)
1.36
(1.03-1.80)
NA
↔ ombitasvir 1.09
(1.01-1.18)
1.02
(1.00-1.05)
0.97
(0.92-1.02)
↔ paritaprevir 1.12
(0.88-1.43)
0.98
(0.85-1.14)
0.71
(0.56-0.89)
↔ dasabuvir 1.10
(0.95-1.27)
1.01
(0.93-1.10)
0.89
(0.79-1.00)
Duloxetine
60 mg single dose
Cmax AUC Cmin No dose adjustment is necessary for duloxetine.
↓ duloxetine 0.79
(0.67-0.94)
0.75
(0.67-0.83)
NA
↔ ombitasvir 0.98
(0.88-1.08)
1.00
(0.95-1.06)
1.01
(0.96-1.06)
↓ paritaprevir 0.79
(0.53-1.16)
0.83
(0.62-1.10)
0.77
(0.65-0.91)
↔ dasabuvir 0.94
(0.81-1.09)
0.92
(0.81-1.04)
0.88
(0.76-1.01)
Trazodone* ↑ Trazodone Mechanism: CYP3A4 inhibition by ritonavir.
Trazodone should be used with caution and a lower dose of trazodone may be considered.
Antifungals
Ketoconazole 400 mg once daily. Cmax AUC Cmin When VIEKIRA PAK-RBV is co- administered with ketoconazole, the maximum daily dose of ketoconazole should be limited to 200 mg per day.
↑ keto- conazole 1.15
(1.09-1.21)
2.17
(2.05-2.29)
NA
↔ ombitasvir 0.98
(0.90-1.06)
1.17
(1.11-1.24)
NA
↑ paritaprevir 1.37
(1.11-1.69)
1.98
(1.63-2.42)
NA
↑ dasabuvir 1.16
(1.03-1.32)
1.42
(1.26-1.59)
NA
Voriconazole* ↓ voriconazole Mechanism: CYP2C19 induction by ritonavir.
Co-administration of VIEKIRA PAK-RBV with voriconazole is not recommended unless an assessment of the benefit-to- risk ratio justifies the use of voriconazole.
Antidiabetic
Metformin No dose adjustments are required when co-administering with VIEKIRA PAK-RBV. Concomitant metformin use in patients with renal insufficiency or hepatic impairment is not recommended
Antigout
Colchicine A reduction in colchicine dosage or an interruption of colchicine treatment is recommended in patients with normal renal or hepatic function if treatment with VIEKIRA PAK-RBV is required. See also the colchicine Product Information.
Use of colchicine is contraindicated with VIEKIRA PAK-RBV in patients with renal or hepatic impairment.
Antihistamines (for systemic use)
Fexofenadine* ↑ fexofenadine Mechanism: OATP1B1 inhibition by paritaprevir.
Caution should be used when VIEKIRA PAK-RBV is co-administered with fexofenadine.
Antihyperlipidemic agent
Gemfibrozil Cmax AUC Cmin 10-fold increase in dasabuvir exposure.
Increased risk of QT-prolongation (see CONTRAINDICATIONS).
↑ paritaprevir 1.21
(0.94-1.57)
1.38
(1.18-1.61)
NA
↑ dasabuvir 2.01
(1.71-2.38)
11.25
(9.05-13.99)
NA
Calcium Channel Blockers
Amlodipine
5 mg single dose
Cmax AUC Cmin Mechanism: CYP3A4 inhibition by ritonavir.
The dose of amlodipine should be decreased by at least 50%. Clinical monitoring of patients is recommended.
↑ amlodipine 1.26
(1.11-1.44)
2.57
(2.31-2.86)
NA
↔ ombitasvir 1.00
(0.95-1.06)
1.00
(0.97-1.04)
1.00
(0.97-1.04)
↓ paritaprevir 0.77
(0.64-0.94)
0.78
(0.68-0.88)
0.88
(0.80-0.95)
↔ dasabuvir 1.05
(0.97-1.14)
1.01
(0.96-1.06)
0.95
(0.89-1.01)
Diltiazem* Verapamil* ↑ diltiazem, verapamil
↑ paritaprevir
↑/↔ dasabuvir
Mechanism:
CYP3A4/P-gp inhibition
Caution is advised due to the expected increase in paritaprevir exposures.
Dose decrease and clinical monitoring of calcium channel blockers is recommended when co-administered with VIEKIRA PAK-RBV.
Nifedipine* ↑ nifedipine Mechanism: CYP3A4 inhibition
Dose decrease and clinical monitoring of calcium channel blockers is recommended when co-administered with VIEKIRA PAK -RBV.
Contraceptives- Oral
Norethindrone No dose adjustments are required when co-administering with VIEKIRA PAK-RBV
Diuretics
Furosemide
20 mg single dose
Cmax AUC Cmin Mechanism: Possibly due to UGT1A1 inhibition by paritaprevir, ombitasvir and dasabuvir.
Patients should be monitored for clinical effects; a decrease in furosemide dose of up to 50% may be required.
↑ furosemide 1.42
(1.17-1.72)
1.08
(1.00-1.17)
NA
↔ ombitasvir 1.14
(1.03-1.26)
1.07
(1.01-1.12)
1.12
(1.08-1.16)
↔ paritaprevir 0.93
(0.63-1.36)
0.92
(0.70-1.21)
1.26
(1.16-1.38)
↔ dasabuvir 1.12
(0.96-1.31)
1.09
(0.96-1.23)
1.06
(0.98-1.14)
HCV Antiviral
Sofosbuvir No dose adjustments are required when co-administering with VIEKIRA PAK-RBV
HIV Antivirals: Protease Inhibitors
Atazanavir 300 mg once
daily (given at the same time)
Cmax AUC Cmin Mechanism: Increase in paritaprevir exposures may be due to inhibition of OATP1B1/B3 and CYP3A by atazanavir. In combination with ritonavir, the Increase in paritaprevir exposures may be due to inhibition of OATP1B1/B3 and CYP3A by atazanavir and CYP3A by the additional dose of ritonavir.
The recommended dose of atazanavir is 300 mg, without ritonavir, in combination with VIEKIRA PAK-RBV. Atazanavir must be administered at the same time as VIEKIRA PAK-RBV. Ritonavir dose in VIEKIRA PAK-RBV will provide atazanavir pharmacokinetic enhancement.
Treatment with atazanavir/ritonavir + VIEKIRA PAK-RBV is not recommended.
↔ atazanavir 0.91
(0.84-0.99)
1.01
(0.93-1.10)
0.90
(0.81-1.01)
↓ ombitasvir 0.77
(0.70-0.85)
0.83
(0.74-0.94)
0.89
(0.78-1.02)
↑ paritaprevir 1.46
(1.06-1.99)
1.94
(1.34-2.81)
3.26
(2.06-5.16)
↔ dasabuvir 0.83
(0.71-0.96)
0.82
(0.71-0.94)
0.79
(0.66-0.94)
Atazanavir/ ritonavir 300/100 mg once daily (administered 12 hours apart) Cmax AUC Cmin
↔ atazanavir 1.02
(0.92-1.13)
1.19
(1.11-1.28)
1.68
(1.44-1.95)
↔ ombitasvir 0.83
(0.72-0.96)
0.90
(0.78-1.02)
1.00
(0.89-1.13)
↑ paritaprevir 2.19
(1.61-2.98)
3.16
(2.40-4.17)
11.95
(8.94-
15.98)
↔ dasabuvir 0.81
(0.73-0.91)
0.81
(0.71-0.92)
0.80
(0.65-0.98)
Darunavir 800 mg once
daily (given at the same time)
Cmax AUC Cmin The recommended dose of darunavir is 800 mg once daily, without ritonavir, when administered at the same time as VIEKIRA PAK-RBV (ritonavir dose in VIEKIRA PAK-RBV will provide darunavir pharmacokinetic enhancement). This regimen can be used in the absence of extensive PI resistance (i.e. lack of darunavir associated RAMs).
Darunavir combined with VIEKIRA PAK- RBV is not recommended in patients with extensive PI resistance.
↓ darunavir 0.92
(0.87-0.98)
0.76
(0.71-0.82)
0.52
(0.47-0.58)
↔ ombitasvir 0.86
(0.77-0.95)
0.86
(0.79-0.94)
0.87
(0.82-0.92)
↑ paritaprevir 1.54
(1.14-2.09)
1.29
(1.04-1.61)
1.30
(1.09-1.54)
↔ dasabuvir 1.10
(0.88-1.37)
0.94
(0.78-1.14)
0.90
(0.76-1.06)
Darunavir/ ritonavir 600/100 mg twice daily Cmax AUC Cmin
↔ darunavir 0.87
(0.79-0.96)
0.80
(0.74-0.86)
0.57
(0.48-0.67)
↓ ombitasvir 0.76
(0.65-0.88)
0.73
(0.66-0.80)
0.73
(0.64-0.83)
↓ paritaprevir 0.70
(0.43-1.12)
0.59
(0.44-0.79)
0.83
(0.69-1.01)
↓ dasabuvir 0.84
(0.67-1.05)
0.73
(0.62-0.86)
0.54
(0.49-0.61)
Darunavir/ritonavir
800/100 mg once daily (administered 12 hours apart)
Cmax AUC Cmin
0,79 1,34 0,54
darunavir (0.70-0.90) (1.25-1.43) (0.48-0.62)
↔ ombitasvir 0.87
(0.82-0.93)
0.87
(0.81-0.93)
0.87
(0.80-0.95)
↓ paritaprevir 0.70
(0.50-0.99)
0.81
(0.60-1.09)
1.59
(1.23-2.05)
↓ dasabuvir 0.75
(0.64-0.88)
0.72
(0.64-0.82)
0.65
(0.58-0.72)
Lopinavir / ritonavir 400/100 mg twice daily2 Cmax AUC Cmin Mechanism: Increase in paritaprevir exposures may be due to inhibition of CYP3A/efflux transporters by lopinavir and higher dose of ritonavir.
Lopinavir/ritonavir 400/100 mg twice daily and 800/200 mg once daily (evening administration) increases paritaprevir concentrations.
Lopinavir/ritonavir use is not recommended with VIEKIRA PAK-RBV.
↔ lopinavir 0.87
(0.76-0.99)
0.94
(0.81-1.10)
1.15
(0.93-1.42)
↔ ombitasvir 1.14
(1.01-1.28)
1.17
(1.07-1.28)
1.24
(1.14-1.34)
↑ paritaprevir 2.04
(1.30-3.20)
2.17
(1.63-2.89)
2.36
(1.00-5.55)
↔ dasabuvir 0.99
(0.75-1.31)
0.93
(0.75-1.15)
0.68
(0.57-0.80)
HIV Antivirals: Non-nucleoside reverse transcriptase inhibitors
Rilpivirine
25 mg once daily administered in the morning, with food 3
Cmax AUC Cmin Mechanism: CYP3A4 inhibition by ritonavir.
Co-administration of VIEKIRA PAK-RBV with rilpivirine once daily is not recommended due to potential for QT interval prolongation with higher concentrations of rilpivirine.
↑ rilpivirine 2.55
(2.08-3.12)
3.25
(2.80-3.77)
3.62
(3.12-4.21)
↔ ombitasvir 1.11
(1.02-1.20)
1.09
(1.04-1.14)
1.05
(1.01-1.08)
↑ paritaprevir 1.30
(0.94-1.81)
1.23
(0.93-1.64)
0.95
(0.84-1.07)
↔ dasabuvir 1.18
(1.02-1.37)
1.17
(0.99-1.38)
1.10
(0.89-1.37)
Efavirenz/emtrici tabine/tenofovir disoproxil fumarate 600/300/200 mg once daily Co-administration of efavirenz (enzyme inducer) based regimens with paritaprevir/ritonavir + dasabuvir resulted in ALT elevations and therefore, early discontinuation of the study. Co-administration of efavirenz based regimens with paritaprevir, ritonavir plus dasabuvir was poorly tolerated and resulted in liver enzyme elevations. (see CONTRAINDICATIONS).
HIV Antivirals: Nucleoside reverse transcriptase inhibitors
Lamivudine No dose adjustments are required when co-administering with VIEKIRA PAK-RBV
Abacavir No dose adjustments are required when co-administering with VIEKIRA PAK-RBV
HIV Antivirals: Integrase strand transfer inhibitor
Dolutegravir
50 mg once daily
Cmax AUC Cmin No dose adjustment is necessary for dolutegravir.
↑dolutegravi r 1.22
(1.15-1.29)
1.38
(1.30-1.47)
1.36
(1.19-1.55)
↔ ombitasvir 0.96
(0.89-1.03)
0.95
(0.90-1.00)
0.92
(0.87-0.98)
↔ paritaprevir 0.89
(0.69-1.14)
0.84
(0.67-1.04)
0.66
(0.59-0.75)
↔ dasabuvir 1.01
(0.92-1.11)
0.98
(0.92-1.05)
0.92
(0.85-0.99)
Raltegravir 400 mg twice daily Cmax AUC Cmin
↑ raltegravir 2.33
(1.66-
3.27)
2.34
(1.70-3.24)
2.00
(1.17-
3.42)
No clinically relevant changes in dasabuvir, paritaprevir and ombitasvir exposures (based on comparison with historical data) were observed during co-administration
HIV ANTIVIRALS: NUCLEOSIDE INHIBITORS
Emtricitabine/ tenofovir 200 mg once daily/300 mg once daily ↔ em- tricitabine 1.05
(1.00-1.12)
1.07
(1.00-1.14)
1.09
(1.01-1.17)
↔ tenofovir 1,07
(0.93-1.24)
1,13
(1.07-1.20)
1,24
(1.13-1.36)
↔ ombitasvir 0.89
(0.81-0.97)
0.99
(0.93-1.05)
0.97
(0.90-1.04)
↓ paritaprevir 0.68
(0.42-1.11)
0.84
(0.59-1.17)
1.06
(0.83-1.35)
↔ dasabuvir 0.85
(0.74-0.98)
0.85
(0.75-0.96)
0.85
(0.73-0.98)
HMG-CoA Reductase Inhibitors
Rosuvastatin
5 mg once daily
Cmax AUC Cmin Mechanism: OATP1B inhibition by paritaprevir and BCRP inhibition by paritaprevir, ritonavir or dasabuvir The maximum daily dose of
rosuvastatin should be 5 mg. Also refer to CONTRAINDICATIONS and PRECAUTIONS.
↑ rosuvastati n 7.13
(5.11-9.96)
2.59
(2.09-3.21)
0.59
(0.51-0.69)
↔ ombitasvir 0.92
(0.82-1.04)
0.89
(0.83-0.95)
0.88
(0.83-0.94)
↑ paritaprevir 1.59
(1.13-2.23)
1.52
(1.23-1.90)
1.43
(1.22-1.68)
↔ dasabuvir 1.07
(0.92-1.24)
1.08
(0.92-1.26)
1.15
(1.05-1.25)
Pravastatin
10 mg once daily
Cmax AUC Cmin Mechanism: OATP1B/CYP3A4 inhibition by paritaprevir.
Reduce pravastatin dose by 50%.
Also refer to CONTRAINDICATIONS and PRECAUTIONS.
↑ pravastatin 1.37
(1.11-1.69)
1.82
(1.60-2.08)
NA
↔ ombitasvir 0.95
(0.89-1.02)
0.89
(0.83-0.95)
0.94
(0.89-0.99)
↔ dasabuvir 1.00
(0.87-1.14)
0.96
(0.85-1.09)
1.03
(0.91-1.15)
↔ paritaprevir 0.96
(0.69-1.32)
1.13
(0.92-1.38)
1.39
(1.21-1.59)
Immunosuppressants
Ciclosporin
30 mg once daily single dose4
Cmax AUC Cmin When starting co-administration with VIEKIRA PAK-RBV, give one fifth of the total daily dose of ciclosporin once daily with VIEKIRA PAK-RBV. Monitor ciclosporin levels and adjust dose and/or dosing frequency as needed.
↑ cilosporin 1.01
(0.85-1.20)
5.82
(4.73-7.14)
15.8
(13.8-
18.09)
↔ ombitasvir 0.99
(0.92-1.07)
1.08
(1.05-1.11)
1.15
(1.08-1.23)
↑ paritaprevir 1.44
(1.16-1.78)
1.72
(1.49-1.99)
1.85
(1.58-2.18)
↓ dasabuvir 0.66
(0.58-0.75)
0.70
(0.65-0.76)
0.76
(0.71-0.82)
Tacrolimus
2 mg single dose
Cmax AUC Cmin Mechanism: Effect on tacrolimus is due to CYP3A4 inhibition by ritonavir.
When starting co-administration with VIEKIRA PAK-RBV, administer 0.5 mg tacrolimus once every week. Monitor tacrolimus levels and adjust dose and/or dosing frequency as needed.
↑ tacrolimus 3.99
(3.21-4.97)
57.1
(45.5-71.7)
16.6
(13.0-21.2)
↔ ombitasvir 0.93
(0.88-0.99)
0.94
(0.89-0.98)
0.94
(0.91-0.96)
↓ paritaprevir 0.57
(0.42-0.78)
0.66
(0.54-0.81)
0.73
(0.66-0.80)
↔ dasabuvir 0.85
(0.73-0.98)
0.90
(0.80-1.02)
1.01
(0.91-1.11)
Insulin Secretagogues
Repaglinide* ↑ repaglinide Mechanism: OATP1B1 inhibition by paritaprevir.
Caution should be used and dose decrease maybe needed for repaglinide.
Iron Chelators
Deferasirox* ↑ dasabuvir Mechanism: CYP2C8 inhibition by deferasirox.
Deferasirox may increase dasabuvir exposures and should be used with caution.
Medicinal Products used in Multiple Sclerosis
Teriflunomide* ↑ dasabuvir CYP2C8 inhibition by teriflunomide. Teriflunomide may increase dasabuvir exposures and should be used with caution.
Muscle Relaxants
Carisoprodol ↓ carisoprodol
↔ mepobramate (metabolite of carisoprodol)
No dose adjustment required; increase dose if clinically indicated
Cyclobenzaprine ↓ cyclobenzaprine
↓ norcyclobenzaprine (metabolite of cyclobenzaprine)
No dose adjustment required; increase dose if clinically indicated
Opioids
Methadone
20-120 mg once daily5
Cmax AUC Cmin No dose adjustment is necessary for methadone.
↔ R- Methadone 1.04
(0.98-1.11)
1.05
(0.98-1.11)
0.94
(0.87-1.01)
↔ S- Methadone 0.99
(0.91-1.08)
0.99
(0.89-1.09)
0.86
(0.76-0.96)
↔ paritaprevir/ombitasvir/dasabuvir (based on the cross- study comparison)
Buprenorphine/ naloxone
4-24 mg/1-6 mg once daily5
Cmax AUC Cmin No dose adjustment is necessary for buprenorphine/naloxone.
↑ bu- prenorphine 2.18
(1.78-2.68)
2.07
(1.78-2.40)
3.12
(2.29-4.27)
↑ norbu- prenorphine 2.07
(1.42-3.01)
1.84
(1.30-2.60)
2.10
(1.49-2.97)
↑ naloxone 1.18
(0.81-1.73)
1.28
(0.92-1.79)
NA
↔ ombitasvir/paritaprevir/dasabuvir (based on the cross- study comparison)
Hydrocodone Cmax AUC Cmin Reduce the dose of hydrocodone by 50% and monitor patients for respiratory depression and sedation at frequent intervals. Upon completion of VIEKIRA PAK-RBV therapy, adjust the hydrocodone dose and monitor for signs of opioid withdrawal
↑ hydrocod one 1.27
(1.14-1.40)
1.90
(1.72-2.10)
NA
↔ ombitasvir 1.01
(0.93-1.10)
0.97
(0.93-1.02)
0.93
(0.90-0.97)
↔ paritaprevir 1.01
(0.80-1.27)
1.03
(0.89-1.18)
1.10
(0.97-1.26)
↔ dasabuvir 1.13
(1.01-1.26)
1.12
(1.05-1.19)
1.16
(1.08-1.25)
Proton Pump Inhibitors
Omeprazole
40 mg once daily
Cmax AUC Cmin Mechanism: CYP2C19 induction by ritonavir.
If clinically indicated higher doses of omeprazole should be used.
↓ omeprazole 0.62
(0.48-0.80)
0.62
(0.51-0.75)
NA
↔ ombitasvir 1.02
(0.95-1.09)
1.05
(0.98-1.12)
1.04
(0.98-1.11)
↔ paritaprevir 1.19
(1.04-1.36)
1.18
(1.03-1.37)
0.92
(0.76-1.12)
↔ dasabuvir 1.13
(1.03-1.25)
1.08
(0.98-1.20)
1.05
(0.93-1.19)
Esomeprazole*, Lansoprazole* ↓ esomeprazole, lansoprazole Mechanism: CYP2C19 induction by ritonavir.
If clinically indicated, higher doses of esomeprazole/lansoprazole may be needed.
Sedatives/hypnotics
Triazolam, orally administered midazolam Large ↑ triazolam, orally administered midazolam Triazolam and orally administered midazolam are extensively metabolised by CYP3A4. Co-administration of triazolam or orally administered midazolam with VIEKIRA PAK-RBV may cause large increases in the concentration of these benzodiazepines. The potential exists for serious and/or life threatening events such as prolonged or increased sedation or respiratory depression. (see CONTRAINDICATIONS).
Zolpidem
5 mg single dose
Cmax AUC Cmin No dose adjustment is necessary for zolpidem.
↔ zolpidem 0.94
(0.76-1.16)
0.95
(0.74-1.23)
NA
↔ ombitasvir 1.07
(1.00-1.15)
1.03
(1.00-1.07)
1.04
(1.00-1.08)
↓ paritaprevir 0.63
(0.46-0.86)
0.68
(0.55-0.85)
1.23
(1.10-1.38)
↔ dasabuvir 0.93
(0.84-1.03)
0.95
(0.84-1.08)
0.92
(0.83-1.01)
Alprazolam
0.5 mg single dose
Cmax AUC Cmin Clinical monitoring of patients is recommended. A decrease in alprazolam dose can be considered based on clinical response.
↑ alprazolam 1.09
(1.03-1.15)
1.34
(1.15-1.55)
NA
↔ ombitasvir 0.98
(0.93-1.04)
1.00
(0.96-1.04)
0.98
(0.93-1.04)
↔ paritaprevir 0.91
(0.64-1.31)
0.96
(0.73-1.27)
1.12
(1.02-1.23)
↔ dasabuvir 0.93
(0.83-1.04)
0.98
(0.87-1.11)
1.00
(0.87-1.15)
diazepam ↓ diazepam
↓ nordiazepam (metabolite of diazepam)
No dose adjustment required; increase dose if clinically indicated.
Thyroid Hormones
Levothyroxine* ↑ levothyroxine Mechanism: UGT1A1 inhibition by paritaprevir, ombitasvir and dasabuvir. Clinical monitoring and dose adjustment may be required for levothyroxine.
* Not studied; expected effect.
1. Drug interaction study carried out with paritaprevir/ritonavir + dasabuvir combination.
2. Lopinavir/ritonavir 800/200 mg once daily (administered in the evening) was also administered with VIEKIRA PAK. The effect on Cmax and AUC of DAAs and lopinavir was similar to that observed when lopinavir/ritonavir
400/100 mg twice daily was administered with VIEKIRA PAK.

3. Rilpivirine was also administered in the evening with food and at night 4 hours after dinner with VIEKIRA PAK in other two arms in the study. The effect on rilpivirine exposures was similar to that observed when rilpivirine was administered in the morning with food with VIEKIRA PAK (shown in the table above).
4. Ciclosporin 100 mg dosed alone and 30 mg administered with VIEKIRA PAK. Dose normalized cyclosporine ratios are shown for interaction with VIEKIRA PAK.
5. Dose normalised parameters reported for methadone, buprenorphine and naloxone.

Note: Doses used for VIEKIRA PAK were: ombitasvir 25 mg, paritaprevir 150 mg, ritonavir 100 mg, once daily and dasabuvir 400 mg twice daily or 250 mg twice daily. The dasabuvir exposures obtained with the 400 mg formulation and the 250 mg tablet are similar. VIEKIRA PAK was administered as multiple doses in all the drug interaction studies except the drug interaction studies with carbamazepine, gemfibrozil and ketoconazole.

Ribavirin-Specific Effects & Recommendations

Any potential for interactions may persist for up to 2 months (5 half-lives for ribavirin) after cessation of ribavirin therapy due to its long half-life.

Results of in vitro studies using both human and rat liver microsome preparations indicated no cytochrome P450 enzyme mediated metabolism of ribavirin. Ribavirin does not inhibit cytochrome P450 enzymes. There is no evidence from toxicity studies that ribavirin induces liver enzymes. Therefore, there is a minimal potential for P450 enzyme-based interactions.

There is no evidence that ribavirin interacts with non-nucleoside reverse transcriptase inhibitors (NNRTIs) or protease inhibitors.

Nucleoside Analogues

Ribavirin was shown in vitro to inhibit phosphorylation of zidovudine and stavudine. The clinical significance of these findings is unknown. However, these in vitro findings raise the possibility that concurrent use of ribavirin with either zidovudine or stavudine might lead to increased HIV plasma viraemia. Therefore, it is recommended that plasma HIV RNA levels be closely monitored in patients treated with ribavirin concurrently with either of these two agents. If HIV RNA levels increase, the use of ribavirin concomitantly with reverse transcriptase inhibitors must be reviewed.

Reverse Transcriptase Inhibitors

Co-administration of ribavirin and didanosine is not recommended. Exposure to didanosine or its active metabolite (dideoxyadenosine 5'-triphosphate) is increased in vitro when didanosine is co-administered with ribavirin. Reports of fatal hepatic failure as well as peripheral neuropathy, pancreatitis, and symptomatic hyperlactataemia/lactic acidosis have been reported with use of ribavirin. Co-administration of ribavirin and didanosine is also not recommended due to the risk of mitochondrial toxicity. Moreover, co-administration of ribavirin and stavudine should be avoided to limit the risk of overlapping mitochondrial toxicity.

Azathioprine

Ribavirin, by having an inhibitory effect on inosine monophosphate dehydrogenase, may interfere with azathioprine metabolism possibly leading to an accumulation of 6-methylthioinosine monophosphate (6-MTIMP), which has been associated with myelotoxicity in patients treated with azathioprine. The use of ribavirin and peginterferon alfa-2a concomitantly with azathioprine should be avoided. In individual cases where the benefit of administering ribavirin concomitantly with azathioprine warrants the potential risk, it is recommended that close haematologic monitoring be done during concomitant azathioprine use to identify signs of myelotoxicity, at which time treatment with these drugs should be stopped.

HIV-HCV Co-Infected Patients

No apparent evidence of drug interaction was observed in 47 HIV-HCV co-infected patients who completed a 12 week pharmacokinetic substudy to examine the effect of ribavirin on the intracellular phosphorylation of some nucleoside reverse transcriptase inhibitors (NRTIs) (lamivudine and zidovudine or stavudine). However, due to high variability, the confidence intervals were quite wide. Plasma exposure of ribavirin did not appear to be affected by concomitant administration of (NRTIs).

Exacerbation of anaemia due to ribavirin has been reported when zidovudine is part of the regimen used to treat HIV, although the exact mechanism remains to be elucidated. The concomitant use of ribavirin with zidovudine is not recommended due to an increased risk of anaemia (see PRECAUTIONS). Consideration should be given to replacing zidovudine in a combination ART regimen if this is already established. This would be particularly important in patients with a known history of zidovudine induced anaemia.

Adverse Effects

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in clinical trials of VIEKIRA PAK-RBV cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The safety summary is based on pooled data from phase 2 and 3 clinical trials in more than 2,600 subjects who received VIEKIRA PAK with or without ribavirin.

VIEKIRA PAK-RBV in Subjects with Genotype 1 Hepatitis C Infection (including subjects with cirrhosis)

In subjects receiving VIEKIRA PAK-RBV, the most commonly reported adverse reactions (greater than 20% of subjects) were fatigue and nausea. The proportion of subjects who permanently discontinued treatment due to adverse events was 1.2% (25/2,044). 1.3% (27/2,044) of subjects interrupted treatment due to adverse events. 7.7% (158/2,044) of subjects had ribavirin dose reductions due to adverse events.

The safety profile of VIEKIRA PAK with ribavirin in subjects with cirrhosis was similar to that of subjects without cirrhosis.

VIEKIRA PAK without Ribavirin in Subjects with Genotype 1 Hepatitis C Infection

In subjects receiving VIEKIRA PAK without ribavirin, pruritus was the only identified adverse reaction (of reactions that occurred in ≥ 5% of subjects )when a comparison of subjects who received VIEKIRA PAK without RBV was made to studies which included both VIEKIRA PAK-RBV and placebo.

The proportion of subjects who permanently discontinued treatment due to adverse events was 0.3% (2/588). 0.5% (3/588) subjects had treatment interruptions due to adverse events.

Table 14 lists adverse drug reactions from two randomised placebo-controlled trials (SAPPHIRE I and SAPPHIRE II) that occurred with at least 5% higher frequency among subjects receiving VIEKIRA PAK in combination with ribavirin compared to subjects receiving placebo, regardless of relationship to VIEKIRA PAK. In addition, Table 14 includes rates of these adverse events from three trials in which subjects received VIEKIRA PAK with or without ribavirin (PEARL II, PEARL III, and PEARL IV), and rates of these adverse events from the trial in subjects with cirrhosis who received VIEKIRA PAK or VIEKIRA-PAK-RBV - for 12 or 24 weeks (TURQUOISE II). A side-by-side tabulation is provided to simplify presentation; direct comparisons should not be made across trials that differ in design.

Table 14: Side-by-Side Tabulation of Adverse Event Rates in Phase 3 Trials Based on Adverse Reactions* (All Grades)
  SAPPHIRE I and II PEARL II, III and IV TURQUOISE II
(subjects with cirrhosis)
Adverse Reaction VIEKIRA PAK + RBV
12 Weeks
N = 770 n (%)
Placebo 12 Weeks
N = 255 n (%)
VIEKIRA PAK + RBV
12 Weeks
N = 401 n (%)
VIEKIRA PAK
12 Weeks
N = 509 n (%)
VIEKIRA PAK + RBV
12 or 24 Weeks
N = 380 n (%)
Fatigue 263 (34.2) 67 (26.3) 120 (29.9) 135 (26.5) 148 (38.9)
Nausea 172 (22.3) 38 (14.9) 63 (15.7) 43 (8.4) 72 (18.9)
Pruritus 121 (15.7) 11 (4.3) 48 (12.0) 31 (6.1)** 71 (18.7)
Insomnia 108 (14.0) 19 (7.5) 49 (12.2) 26 (5.1) 63 (16.6)
Asthenia 104 (13.5) 17 (6.7) 36 (9.0) 20 (3.9) 51 (13.4)
Anaemia 41 (5.3) 0 30 (7.5) 1 (0.2) 34 (8.9)
*Adverse drug reactions for VIEKIRA PAK - RBV listed are those with a 5% higher frequency among subjects receiving VIEKIRA PAK in combination with ribavirin compared to subjects receiving placebo in SAPPHIRE I and II.
** Adverse drug reaction for VIEKIRA PAK defined as the subset of ADRs for the VIEKIRA PAK- RBV for which the risk difference (VIEKIRA PAK-RBV minus VIEKIRA PAK) in PEARL II, III, and IV was at least 5.0 % lower than the risk difference (VIEKIRA PAK-RBV minus placebo) in SAPPHIRE I and II.

The majority of adverse events in the Phase 3 clinical trials were of grade 1 severity. The safety profile of VIEKIRA PAK-RBV was consistent with the known safety profile of ribavirin.

In addition to the adverse reaction listed in Table 14, treatment-emergent adverse events that occurred with at least 2% frequency and less than 5% higher frequency among subjects receiving VIEKIRA PAK-RBV compared to subjects receiving placebo (SAPPHIRE I and II), are listed below by system organ class.

Gastrointestinal Disorders: Diarrhoea and vomiting
Investigations: Haemoglobin decreased
Metabolism and Nutrition Disorders: Decreased appetite
Nervous System Disorders: Dizziness and headache
Psychiatric Disorders: Sleep disorder
Respiratory, Thoracic and Mediastinal Disorders: Cough and dyspnoea
Skin and Subcutaneous Tissue Disorders: Dry skin, and rash

Post-Marketing Adverse Reactions

The following adverse reactions have been identified during post approval use of paritaprevir/ritonavir/ombitasvir with and without dasabuvir. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Immune System Disorders: Hypersensitivity reactions (including tongue and lip swelling) have been observed (See CONTRAINDICATIONS).

Hepatobiliary Disorders: Hepatic decompensation and hepatic failure have been observed (see PRECAUTIONS).

Dosage and Administration

Ribavirin monotherapy is not effective and ribavirin must only be used in combination with VIEKIRA PAK.

VIEKIRA PAK-RBV is paritaprevir/ritonavir/ombitasvir fixed dose combination tablets copackaged with dasabuvir tablets and ribavirin tablets.

Paritaprevir/ritonavir/ombitasvir tablets must be administered with dasabuvir tablets.

Recommended Dose in Adults

The recommended oral dose of VIEKIRA PAK-RBV is two paritaprevir/ritonavir/ombitasvir 75/50/12.5 mg tablets once daily (in the morning) and one dasabuvir 250 mg tablet twice daily (morning and evening).

The recommended dose of ribavirin depends on patient's body weight (<75 kg = 1000 mg and ≥75 kg = 1200 mg), and should be taken with food in two doses (morning and evening).

VIEKIRA PAK-RBV is used in cirrhotic genotype 1 and non-cirrhotic genotype 1a infected patients (see Table 15. Patients should be instructed to swallow the tablets whole (i.e. patients should not chew, break or dissolve the tablets).

To maximise absorption, VIEKIRA PAK-RBV should be taken with food without regard to fat or calorie content (see PHARMACOLOGY).

Table 15 shows the recommended treatment regimen and duration based on patient population.

Table 15: Treatment Regimen and Duration by Patient Population
Patient Population Treatment Duration Ribavirin Dosage
Genotype 1b, without cirrhosis VIEKIRA PAK 12 weeks NA
Genotype 1a, without cirrhosis VIEKIRA PAK- RBV* 12 weeks < 75 kg = 1000 mg
≥ 75 kg = 1200 mg
Ribavirin is to be taken in two doses, morning and evening
Genotype 1 with cirrhosis VIEKIRA PAK- RBV 12 weeks < 75 kg = 1000 mg
≥ 75 kg = 1200 mg
Ribavirin is to be taken in two doses, morning and evening
*         VIEKIRA  PAK  without  ribavirin  can  be  considered  as  a  therapeutic  option  for  treatment-naïve patients with genotype 1a infection without cirrhosis (see CLINICAL TRIALS). Treatment decision should be guided by an assessment of the potential benefits and risks and available alternative therapies for the individual patient.
†                24  weeks  of  VIEKIRA  PAK–RBV  is  recommended  for  patients  with  genotype  1a-infection  with cirrhosis who have had a previous null response to pegIFN and ribavirin (see CLINICAL TRIALS).
Note:  VIEKIRA  PAK-RBV  is  recommended  in  patients  with  an  unknown  genotype  1  subtype  or  with mixed genotype 1 infection.

VIEKIRA PAK-RBV should be taken as directed for the prescribed duration, without interruption. If VIEKIRA PAK is used in combination with ribavirin, ribavirin should be administered for the same duration as VIEKIRA PAK.

Missed Dose

Inform patients that in case a dose of paritaprevir, ritonavir, ombitasvir is missed, the prescribed dose can be taken within 12 hours.

In case a dose of dasabuvir is missed, the prescribed dose can be taken within 6 hours.

If more than 12 hours has passed since ombitasvir, paritaprevir, ritonavir is usually taken or more than 6 hours has passed since dasabuvir is usually taken, the missed dose should NOT be taken and the patient should take the next dose as per the usual dosing schedule.

In case a dose of ribavirin is missed, the missed dose should be taken as soon as possible during the same day. Patients should not double the next dose. Patients should be advised to call their healthcare provider if they have questions.

Instruct patients not to take more than their prescribed dose of VIEKIRA PAK- RBV to make up for a missed dose.

Dosage Modification of RBV for Adverse Reactions

If suspected severe adverse reactions or laboratory abnormalities related to RBV develop during the combination therapy, modify the dosages of RBV, until the adverse reactions abate.

Guidelines were developed in clinical trials for RBV dose modification (see RBV Dosage Modification Guidelines for Management of Treatment-Emergent Anaemia, Table 16). If intolerance persists after dose adjustment, discontinuation of ribavirin therapy may be needed.

Table 16: RBV Dosage Modification Guidelines for Management of Treatment- Emergent Anaemia
Laboratory Values Reduce Only ribavirin Dose to 600 mg/Day* if: Discontinue ribavirin if:**
Haemoglobin in Patients with No Cardiac Disease <100 g/l <85 g/l
Haemoglobin: Patients with History of Stable Cardiac Disease >20 g/l decrease in haemoglobin during any 4 week period during treatment (permanent dose reduction) <120 g/l despite 4 weeks at reduced dose

* Patients whose dose of ribavirin is reduced to 600 mg daily receive one 200 mg tablet in the morning and two 200 mg tablets or one 400 mg tablet in the evening.

** If the abnormality is reversed, ribavirin may be restarted at 600 mg daily, and further increased to 800 mg daily at the discretion of the treating physician. However, a return to higher doses is not recommended.

Use in Special Populations

Hepatic Impairment

No dosage adjustment of VIEKIRA PAK-RBV is required in patients with mild hepatic impairment (Child-Pugh A). VIEKIRA PAK-RBV is not recommended in patients with moderate hepatic impairment (Child-Pugh B). A decision to initiate treatment in patients with Child-Pugh B should be guided by assessment of the potential benefits and risks for the individual. VIEKIRA PAK-RBV is contraindicated in patients with severe hepatic impairment (Child-Pugh C) (see CONTRAINDICATIONS and PRECAUTIONS)

Hepatic function does not affect the pharmacokinetics of ribavirin (see Pharmacokinetics). Therefore, no dose adjustment of ribavirin is required in patients with hepatic impairment.

Renal Impairment

Based on the pharmacokinetic data in HCV uninfected subjects (n=24), no dose adjustment of VIEKIRA PAK-RBV is recommended in subjects with mild, moderate or severe renal impairment. The efficacy and safety of VIEKIRA PAK-RBV have not been evaluated in HCV-infected subjects with moderate or severe renal impairment. VIEKIRA PAK-RBV has not been studied in patients on dialysis.

Substantial increases in plasma concentrations of ribavirin in patients with renal impairment have been noted at the recommended doses. There are insufficient data on the safety and efficacy of ribavirin in patients with serum creatinine >2 mg/dL or creatinine clearance <50 mL/min, whether or not on haemodialysis, to support recommendations for dose adjustments. Therefore, ribavirin should be used in such patients only when this is considered to be essential. Therapy should be initiated (or continued if renal impairment develops while on therapy) with extreme caution and intensive monitoring of haemoglobin concentrations, with corrective action as may be necessary, should be employed throughout the treatment period (see PRECAUTIONS and Pharmacokinetics).

Elderly Patients ( > 65 years)

There does not appear to be a significant age-related effect on the pharmacokinetics of ribavirin. However, as in younger patients, renal function must be determined prior to administration of ribavirin.

Patients under the Age of 18 Years

Treatment with ribavirin tablet is not recommended for use in children and adolescents (<18 years) due to insufficient data on safety and efficacy in combination with VIEKIRA PAK.

Overdosage

The highest documented single dose administered to healthy volunteers was 400 mg for paritaprevir (with 100 mg ritonavir), 200 mg for ritonavir (with 100 mg paritaprevir), 350 mg for ombitasvir and 2000 mg for dasabuvir. In case of overdose, it is recommended that the patient be monitored for any signs or symptoms of adverse reactions or effects and appropriate symptomatic treatment instituted immediately.

No cases of overdose of ribavirin have been reported in clinical trials. Hypocalcaemia and hypomagnesaemia have been observed in persons administered dosages greater than four times the maximal recommended dosages. In many of these instances ribavirin was administered intravenously.

Due to the large volume of distribution of ribavirin, significant amounts of ribavirin are not effectively removed by haemodialysis.

For information on the management of overdose in Australia contact the Poison Information Centre on 131126 and in New Zealand call 0800 764 766.

Presentation and Storage Conditions

Presentation

Paritaprevir/ritonavir/ombitasvir 75/50/12.5 mg tablets are pink-coloured, film-coated, oblong biconvex shaped, debossed with “AV1” on one side.

Dasabuvir 250 mg tablets are beige-coloured, film-coated, oval-shaped, debossed with “AV2” on one side

Ribavirin 200 mg tablets are light-blue, film-coated, oblong-shaped and debossed with “200” on one side and “3RP” on the other side.

Ribavirin 400 mg tablets are blue, film-coated, oblong-shaped and debossed with “400” on one side and “3RP” on the other side.

Ribavirin 600 mg tablets are deep-blue, film-coated, oblong-shaped and debossed with “600” on one side and “3RP” on the other side.

VIEKIRA PAK-RBV (200) is supplied in a monthly carton for a total of 28 days of therapy. Each monthly carton contains four weekly cartons together with 200 mg ribavirin supplied in a HDPE bottle of 168 tablets of ribavirin 200 mg. Each weekly carton contains seven daily dose packs. Each daily dose pack contains four tablets: two 75 mg/50 mg/12.5 mg paritaprevir/ritonavir/ombitasvir tablets and two 250 mg dasabuvir tablets in PVC/PE/PCTFE(Aclar)/Al blisters with dosing instructions.

VIEKIRA PAK-RBV (400) is supplied in a monthly carton for a total of 28 days of therapy. Each monthly carton contains four weekly cartons together with 200 mg ribavirin supplied a HDPE bottle of 56 tablets of ribavirin 400 mg. Each weekly carton contains seven daily dose packs. Each daily dose pack contains four tablets: two 75 mg/50 mg/12.5 mg paritaprevir/ritonavir/ombitasvir tablets and two 250 mg dasabuvir tablets in PVC/PE/PCTFE(Aclar)/Al blisters with dosing instructions*.

VIEKIRA PAK-RBV (1000) is supplied in a monthly carton for a total of 28 days of therapy. Each monthly carton contains four weekly cartons together with 4 PVC/PCTFE(Aclar)/Al blister cartons of 7 tablets of ribavirin 600 mg and 7 tablets of 400 mg ribavirin. Each weekly carton contains seven daily dose packs. Each daily dose pack contains four tablets: two 75 mg/50 mg/12.5 mg paritaprevir/ritonavir/ombitasvir tablets and two 250 mg dasabuvir tablets in PVC/PE/PCTFE(Aclar)/Al blisters with dosing instructions*.

VIEKIRA PAK-RBV (1200) is supplied in a monthly carton for a total of 28 days of therapy. Each monthly carton contains four weekly cartons together with 4 PVC/PCTFE(Aclar)/Al blister cartons of 14 tablets of ribavirin 600 mg or a HDPE bottle of 56 tablets. Each weekly carton contains seven daily dose packs. Each daily dose pack contains four tablets: two 75 mg/50 mg/12.5 mg paritaprevir/ritonavir/ombitasvir tablets and two 250 mg dasabuvir tablets in PVC/PE/PCTFE(Aclar)/Al blisters with dosing instructions (only HDPE bottles of 600mg ribavirin are currently marketed).

* Not currently marketed

Storage Conditions

Store below 25°C in a dry place.

Name and Address of the Sponsor

AbbVie Pty Ltd

Level 7, 241 O’Riordan Street

Mascot NSW 2020

Australia

AbbVie Limited

6th Floor, 156-158 Victoria St

Wellington, 6011

New Zealand

Poison Schedule of the Medicine

Prescription Only Medicine

Schedule 4

Date of First Inclusion in the ARTG

21 July 2015

Date of Most Recent Amendment

09 Aug 2016