Clinical Pharmacology for Viekira Pak
Mechanism Of Action
VIEKIRA PAK combines three direct-acting hepatitis C virus antiviral agents with distinct mechanisms of action [see Microbiology].
Ritonavir is not active against HCV. Ritonavir is a potent CYP3A inhibitor that increases peak and trough plasma drug concentrations of paritaprevir and overall drug exposure (i.e., area under the curve).
Pharmacodynamics
Cardiac Electrophysiology
The effect of a combination of ombitasvir, paritaprevir, ritonavir, and dasabuvir on QTc interval was evaluated in a randomized, double blind, placebo and active-controlled (moxifloxacin 400 mg) 4-way crossover thorough QT study in 60 healthy subjects. At concentrations approximately 6, 1.8 and 2 times the therapeutic concentrations of paritaprevir, ombitasvir, and dasabuvir, the combination did not prolong QTc to any clinically relevant extent.
Pharmacokinetics
The pharmacokinetic properties of the components of VIEKIRA PAK are provided in Table 5. Based on the population pharmacokinetic analysis, the median steady-state pharmacokinetic parameters of ombitasvir, paritaprevir, ritonavir and dasabuvir in HCV-infected subjects are provided in Table 6.
Table 5: Pharmacokinetic Properties of the Components of VIEKIRA PAK
| Ombitasvir | Paritaprevir | Ritonavir | Dasabuvir |
| Absorption |
| Tmax (hr) | ~ 5 | ~4-5 | -4-5 | ~4 |
| Absolute bioavailability (%) | 48 | 53 | NA | 70 |
| Effect of moderate fat meal (relative to fasting)a | 1.82 (1.61-2.05) | 3.11 (2.16-4.46) | 1.49 (1.23-1.79) | 1.30 (1.08-1.55) |
| Effect of high fat meal (relative to fasting)a | 1.76 (1.56-1.99) | 2.80 (1.95-4.02) | 1.44 (1.19-1.73) | 1.22 (1.01-1.46) |
| Accumulationb | 0.90-to 1.03-fold | 1.5-to 2-fold | 0.96-fold |
| Distribution |
| % Bound to human plasma proteins | 99.9 | 97-98.6 | >99 | >99.5 |
| Blood-to-plasma ratio | 0.49 | 0.7 | 0.6 | 0.7 |
| Volume of distribution at steady state (Vss) (L) | 173 | 103 | 21.5c | 149 |
| Metabolism |
| Metabolism | amide hydrolysis followed by oxidative metabolism | CYP3A4 (major), CYP3A5 | CYP3A (major), CYP2D6 | CYP2C8 (major), CYP3A |
| Eliminationd |
| Major route of elimination | biliary excretion | metabolism | metabolism | metabolism |
| t½ (hr)e | 21-25 | 5.5 | 4 | 5.5-6 |
| % of dose excreted in fecesf | 90.2 | 88 | 86.4 | 94.4 |
| % of dose excreted unchanged in fecesf | 87.8 | 1.1 | 33.8 | 26.2 |
| % of dose excreted in urinef | 1.91 | 8.8 | 11.3 | -2 |
| % of dose excreted unchanged in urinef | 0.03 | 0.05 | 3.5 | 0.03 |
NA - data not available a. Values refer to mean non-fasting/fasting ratios (90% CI) in systemic exposure (AUC). Moderate fat meal ~600 Kcal, 20-30% calories from fat. High fat meal ~900 Kcal, 60% calories from fat. b. Steady state exposures are achieved after approximately 12 days of dosing. c. It is apparent volume of distribution (V/F) for ritonavir. d. Ombitasvir, paritaprevir, ritonavir, and dasabuvir do not inhibit organic anion transporter (OAT1) in vivo and based on in vitro data, are not expected to inhibit organic cation transporter (OCT2), organic anion transporter (OAT3), or multidrug and toxin extrusion proteins (MATE1 and MATE2K) at clinically relevant concentrations. e. t½ values refer to the mean elimination half-life. f. Dosing in mass balance studies: single dose administration of [14C]ombitasvir; single dose administration of [14C]paritaprevir co-dosed with 100 mg ritonavir; single dose administration of [14C]dasabuvir. |
Table 6: Steady-State Pharmacokinetic Parameters of Ombitasvir, Paritaprevir, Ritonavir and Dasabuvir Following Oral Administration of VIEKIRA PAK in HCV-Infected Subjects
| Pharmacokinetic Parametera | Ombitasvir | Paritaprevir | Ritonavir | Dasabuvir |
| Cmax (ng/mL) | 68 | 262 | 682 | 667 |
| AUCtau (ng*h/mL)b | 1000 | 2220 | 6180 | 3240 |
a. Median values reported based on the population PK analysis. b. AUC0-24 for ombitasvir, paritaprevir, ritonavir and AUC0-12 for dasabuvir. |
Specific Populations
Hepatic Impairment
The single dose pharmacokinetics of ombitasvir, paritaprevir, ritonavir and dasabuvir were evaluated in non-HCV infected subjects with mild hepatic impairment (Child-Pugh Category A; score of 5-6), moderate hepatic impairment (Child-Pugh Category B, score of 7-9) and severe hepatic impairment (Child-Pugh Category C, score of 10-15).
Relative to subjects with normal hepatic function, ombitasvir, paritaprevir and ritonavir AUC values decreased by 8%, 29% and 34%, respectively, and dasabuvir AUC values increased by 17% in subjects with mild hepatic impairment.
Relative to subjects with normal hepatic function, ombitasvir, ritonavir and dasabuvir AUC values decreased by 30%, 30% and 16%, respectively, and paritaprevir AUC values increased by 62% in subjects with moderate hepatic impairment.
Relative to subjects with normal hepatic function, paritaprevir, ritonavir and dasabuvir AUC values increased by 945%, 13%, and 325% respectively, and ombitasvir AUC values decreased by 54% in subjects with severe hepatic impairment [see DOSAGE AND ADMINISTRATION, CONTRAINDICATIONS, WARNINGS AND PRECAUTIONS and Use In Specific Populations].
Renal Impairment
The single dose pharmacokinetics of ombitasvir, paritaprevir, ritonavir and dasabuvir were evaluated in non-HCV infected subjects with mild (CLcr : 60 to 89 mL/min), moderate (CLcr : 30 to 59 mL/min), and severe (CLcr : 15 to 29 mL/min) renal impairment.
Overall, changes in exposure of ombitasvir, paritaprevir, ritonavir and dasabuvir in non-HCV infected subjects with mild-, moderate- and severe renal impairment are not expected to be clinically relevant. Pharmacokinetic data are not available on the use of VIEKIRA PAK in non-HCV infected subjects with End Stage Renal Disease (ESRD).
Relative to subjects with normal renal function, paritaprevir, ritonavir and dasabuvir AUC values increased by 19%, 42% and 21%, respectively, while ombitasvir AUC values were unchanged in subjects with mild renal impairment.
Relative to subjects with normal renal function, paritaprevir, ritonavir and dasabuvir AUC values increased by 33%, 80% and 37%, respectively, while ombitasvir AUC values were unchanged in subjects with moderate renal impairment.
Relative to subjects with normal renal function, paritaprevir, ritonavir and dasabuvir AUC values increased by 45%, 114% and 50%, respectively, while ombitasvir AUC values were unchanged in subjects with severe renal impairment [see Use In Specific Populations].
Pediatric Population
The pharmacokinetics of VIEKIRA PAK in pediatric patients less than 18 years of age has not been established [see Use In Specific Populations].
Sex
No dose adjustment is recommended based on sex or body weight.
Race/Ethnicity
No dose adjustment is recommended based on race or ethnicity.
Age
No dose adjustment is recommended in geriatric patients [see Use In Specific Populations].
Drug Interaction Studies
See also CONTRAINDICATIONS, WARNINGS AND PRECAUTIONS, DRUG INTERACTIONS
The effects of drugs discussed in Table 4 on the exposures of the individual components of VIEKIRA PAK are shown in Table 7. For information regarding clinical recommendations, see DRUG INTERACTIONS.
Table 7: Drug Interactions: Change in Pharmacokinetic Parameters of the Individual Components of VIEKIRA PAK in the Presence of Co-administered Drug
| Co-administered Drug | Dose of Co-administered Drug (mg) | n | DAA | Ratio (with/without co-administered drug) of DAA Pharmacokinetic Parameters (90% CI); No Effect = 1.00 |
| Cmax | AUC | Cmin |
| Alprazolam | 0.5 single dose | 12 | 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) |
| ritonavir | 0.92 (0.84, 1.02) | 0.96 (0.89, 1.03) | 1.01 (0.94, 1.09) |
| dasabuvir | 0.93 (0.83, 1.04) | 0.98 (0.87, 1.11) | 1.00 (0.87, 1.15) |
| Amlodipine | 5 single dose | 14 | 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) |
| ritonavir | 0.96 (0.87, 1.06) | 0.93 (0.89,0.98) | 0.95 (0.89, 1.01) |
| dasabuvir | 1.05 (0.97, 1.14) | 1.01 (0.96, 1.06) | 0.95 (0.89, 1.01) |
| Atazanavir/ ritonavir3 | Atazanavir 300 and ritonavir 100 once daily in the evening | 11 | 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) |
| ritonavir | 1.60 (1.38, 1.86) | 3.18 (2.74, 3.69) | 24.65 (18.64, 32.60) |
| dasabuvir | 0.81 (0.73,0.91) | 0.81 (0.71,0.92) | 0.80 (0.65,0.98) |
| Carbamazepine | 200 once daily followed by 200 twice daily | 12 | ombitasvir | 0.69 (0.61,0.78) | 0.69 (0.64, 0.74) | NA |
| paritaprevir | 0.34 (0.25,0.48) | 0.30 (0.23,0.38) | NA |
| ritonavir | 0.17 (0.12,0.24) | 0.13 (0.09,0.17) | NA |
| dasabuvir | 0.45 (0.41,0.50) | 0.30 (0.28,0.33) | NA |
| Carisoprodol | 250 single dose | 14 | ombitasvir | 0.98 (0.92, 1.04) | 0.95 (0.92,0.97) | 0.96 (0.92,0.99) |
| paritaprevir | 0.88 (0.75, 1.03) | 0.96 (0.85, 1.08) | 1.14 (1.02, 1.27) |
| ritonavir | 0.94 (0.87, 1.02) | 0.94 (0.88,0.99) | 0.95 (0.89, 1.03) |
| dasabuvir | 0.96 (0.91, 1.01) | 1.02 (0.97, 1.07) | 1.00 (0.92, 1.10) |
| Cyclobenzaprine | 5 single dose | 14 | ombitasvir | 0.98 (0.92, 1.04) | 1.00 (0.97, 1.03) | 1.01 (0.98, 1.04) |
| paritaprevir | 1.14 (0.99, 1.32) | 1.13 (1.00, 1.28) | 1.13 (1.01, 1.25) |
| ritonavir | 0.93 (0.87,0.99) | 1.00 (0.95, 1.06) | 1.13 (1.05, 1.21) |
| dasabuvir | 0.98 (0.90, 1.07) | 1.01 (0.96, 1.06) | 1.13 (1.07, 1.18) |
| Cyclosporine | 30 single doseb | 10 | 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) |
| ritonavir | 0.90 (0.78, 1.04) | 1.11 (1.04, 1.19) | 1.49 (1.28, 1.74) |
| dasabuvir | 0.66 (0.58,0.75) | 0.70 (0.65, 0.76) | 0.76 (0.71,0.82) |
| Darunavirc | 800 once daily | 9 | 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) |
| ritonavir | 0.84 (0.72, 0.98) | 0.85 (0.78,0.93) | 1.07 (0.93, 1.23) |
| dasabuvir | 1.10 (0.88, 1.37) | 0.94 (0.78, 1.14) | 0.90 (0.76, 1.06) |
| Darunavir/ ritonavird | Darunavir 600 twice daily and ritonavir 100 once daily in the evening | 7 | 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) |
| ritonavir | 1.61 (1.30,2.00) | 1.28 (1.12, 1.45) | 0.88 (0.79,0.99) |
| dasabuvir | 0.84 (0.67, 1.05) | 0.73 (0.62, 0.86) | 0.54 (0.49,0.61) |
| Darunavir/ ritonavire | Darunavir 800 and ritonavir 100 once daily in the evening | 12 | 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) |
| ritonavir | 1.19 (1.06, 1.33) | 1.70 (1.54, 1.88) | 14.15 (11.66,17.18) |
| dasabuvir | 0.75 (0.64, 0.88) | 0.72 (0.64, 0.82) | 0.65 (0.58, 0.72) |
| Diazepam | 2 single dose | 13 | ombitasvir | 1.00 (0.93, 1.08) | 0.98 (0.93, 1.03) | 0.93 (0.88,0.98) |
| paritaprevir | 0.95 (0.77, 1.18) | 0.91 (0.78, 1.07) | 0.92 (0.82, 1.03) |
| ritonavir | 1.10 (1.02, 1.19) | 1.06 (0.98, 1.14) | 0.98 (0.92, 1.03) |
| dasabuvir | 1.05 (0.98, 1.13) | 1.01 (0.94, 1.08) | 1.05 (0.98, 1.12) |
| Ethinyl estradiol/ Norgestimate | Ethinyl estradiol 0.035 and Norgestimate 0.25 once daily | 7f | ombitasvir | 1.05 (0.81, 1.35) | 0.97 (0.81, 1.15) | 1.00 (0.88, 1.12) |
| paritaprevir | 0.70 (0.40, 1.21) | 0.66 (0.42, 1.04) | 0.87 (0.67, 1.14) |
| ritonavir | 0.80 (0.53, 1.21) | 0.71 (0.54, 0.94) | 0.79 (0.68,0.93) |
| dasabuvir | 0.51 (0.22, 1.18) | 0.48 (0.23, 1.02) | 0.53 (0.30,0.95) |
| Everolimus | 0.75 single dose | 12 | ombitasvir | 0.99 (0.95, 1.03) | 1.02 (0.99, 1.05) | 1.02 (0.99, 1.06) |
| paritaprevir | 1.22 (1.03, 1.43) | 1.26 (1.07, 1.49) | 1.06 (0.97, 1.16) |
| ritonavir | 1.07 (0.99, 1.16) | 1.05 (1.00, 1.10) | 1.07 (1.02, 1.13) |
| dasabuvir | 1.03 (0.90, 1.18) | 1.08 (0.98, 1.20) | 1.14 (1.05, 1.23) |
| Furosemide | 20 single dose | 12 | 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) |
| ritonavir | 1.10(0.96, 1.27) | 1.04(0.92, 1.18) | 1.07(0.99, 1.17) |
| dasabuvir | 1.12 (0.96, 1.31) | 1.09 (0.96, 1.23) | 1.06 (0.98, 1.14) |
| Gemfibrozilg | 600 twice daily | 11 | ombitasvir | NA | NA | NA |
| paritaprevir | 1.21 (0.94, 1.57) | 1.38 (1.18, 1.61) | NA |
| ritonavir | 0.84 (0.69, 1.03) | 0.90 (0.78, 1.04) | NA |
| dasabuvir | 2.01 (1.71,2.38) | 11.25 (9.05, 13.99) | NA |
| Hydrocodone/ Acetaminophen | 5/300 single dose | 15 | 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) |
| ritonavir | 1.01 (0.90, 1.13) | 1.03 (0.96, 1.09) | 1.01 (0.93, 1.10) |
| dasabuvir | 1.13 (1.01, 1.26) | 1.12 (1.05, 1.19) | 1.16 (1.08, 1.25) |
| Ketoconazole | 400 once daily | 12 | 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 |
| ritonavir | 1.27 (1.04, 1.56) | 1.57 (1.36, 1.81) | NA |
| dasabuvir | 1.16 (1.03, 1.32) | 1.42 (1.26, 1.59) | NA |
| Lopinavir/ ritonavir | 400/100 twice daily | 6 | 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) |
| ritonavir | 1.55 (1.16,2.09) | 2.05 (1.49,2.81) | 5.25 (3.33,8.28) |
| dasabuvir | 0.99 (0.75, 1.31) | 0.93 (0.75, 1.15) | 0.68 (0.57,0.80) |
| Lopinavir/ ritonavirh | 800/200 once daily | 12 | ombitasvir | 0.87 (0.83,0.92) | 0.97 (0.94, 1.02) | 1.11 (1.06, 1.16) |
| paritaprevir | 0.99 (0.79, 1.25) | 1.87 (1.40,2.52) | 8.23 (5.18, 13.07) |
| ritonavir | 1.57 (1.34, 1.83) | 2.62 (2.32,2.97) | 19.46 (15.93,23.77) |
| dasabuvir | 0.56 (0.47, 0.66) | 0.54 (0.46, 0.65) | 0.47 (0.39,0.58) |
| Omeprazole | 40 once daily | 11 | 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) |
| ritonavir | 1.04 (0.96, 1.12) | 1.02 (0.97, 1.08) | 0.97 (0.89, 1.05) |
| dasabuvir | 1.13 (1.03, 1.25) | 1.08 (0.98, 1.20) | 1.05 (0.93, 1.19) |
| Pravastatin | 10 once daily | 12 | ombitasvir | 0.95 (0.89, 1.02) | 0.94 (0.89,0.99) | 0.94 (0.89,0.99) |
| paritaprevir | 0.96 (0.69, 1.32) | 1.13 (0.92, 1.38) | 1.39 (1.21, 1.59) |
| ritonavir | 0.89 (0.73, 1.09) | 0.95 (0.86, 1.05) | 1.08 (0.98, 1.19) |
| dasabuvir | 1.00 (0.87, 1.14) | 0.96 (0.85, 1.09) | 1.03 (0.91, 1.15) |
| Rilpivirine | 25 once daily (morning)i | 10 | 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) |
| ritonavir | 1.10 (0.98, 1.24) | 1.08 (0.93, 1.27) | 0.97 (0.91, 1.04) |
| dasabuvir | 1.18 (1.02, 1.37) | 1.17 (0.99, 1.38) | 1.10 (0.89, 1.37) |
| Rosuvastatin | 5 once daily | 11 | 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) |
| ritonavir | 0.98 (0.84, 1.15) | 1.02 (0.93, 1.12) | 1.00 (0.90, 1.12) |
| dasabuvir | 1.07 (0.92, 1.24) | 1.08 (0.92, 1.26) | 1.15 (1.05, 1.25) |
| Sirolimus | 0.5 single dosej | 11 | ombitasvir | 1.03 (0.93, 1.15) | 1.02 (0.96, 1.09) | 1.05 (0.98, 1.12) |
| paritaprevir | 1.18 (0.91, 1.54) | 1.19 (0.97, 1.46) | 1.16 (1.00, 1.34) |
| ritonavir | 1.00 (0.85, 1.17) | 1.04 (0.94, 1.15) | 1.10 (1.04, 1.17) |
| dasabuvir | 1.04 (0.89, 1.22) | 1.07 (0.95, 1.22) | 1.13 (1.01, 1.25) |
| Tacrolimus | 2 single dose | 12 | 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) |
| ritonavir | 0.76 (0.63,0.91) | 0.87 (0.79,0.97) | 1.03 (0.89, 1.19) |
| dasabuvir | 0.85 (0.73,0.98) | 0.90 (0.80, 1.02) | 1.01 (0.91, 1.11) |
a. Atazanavir plus 100 mg ritonavir administered in the evening, 12 hours after morning dose of VIEKIRA PAK. b. 30 mg cyclosporine was administered with VIEKIRA PAK in the test arm and 100 mg cyclosporine was administered in the reference arm without VIEKIRA PAK. c. Darunavir administered with VIEKIRA PAK in the morning was compared to darunavir administered with 100 mg ritonavir in the morning. d. Darunavir administered with VIEKIRA PAK in the morning and with 100 mg ritonavir in the evening was compared to darunavir administered with 100 mg ritonavir in the morning and evening. e. Darunavir plus 100 mg ritonavir administered in the evening, 12 hours after the morning dose of VIEKIRA PAK compared to darunavir administered with 100 mg ritonavir in the evening. f. N=3 for dasabuvir. g. Study was conducted with paritaprevir, ritonavir and dasabuvir. h. Lopinavir/ritonavir administered in the evening, 12 hours after morning dose of VIEKIRA PAK. i. Similar increases were observed when rilpivirine was dosed in the evening with food or 4 hours after food. j. 0.5 mg sirolimus was administered with VIEKIRA PAK in the test arm and 2 mg sirolimus was administered in the reference arm without VIEKIRA PAK. NA: not available/not applicable; DAA: Direct-acting antiviral agent; CI: Confidence interval Doses of ombitasvir, paritaprevir, and ritonavir were 25 mg, 150 mg and 100 mg. Doses of dasabuvir were 250 mg or 400 mg (both doses showed similar exposures). Ombitasvir, paritaprevir and ritonavir were dosed once daily and dasabuvir was dosed twice daily in all the above studies except studies with gemfibrozil, ketoconazole and carbamazepine that used single doses. |
Table 8 summarizes the effects of VIEKIRA PAK on the pharmacokinetics of co-administered drugs which showed clinically relevant changes. For information regarding clinical recommendations, see DRUG INTERACTIONS.
Table 8: Drug Interactions: Change in Pharmacokinetic Parameters for Co-administered Drug in the Presence of VIEKIRA PAK
| Co-administered Drug | Dose of Co-administered Drug (mg) | n | Ratio (with/without VIEKIRA PAK) of Co-administered Drug Pharmacokinetic Parameters (90% CI); No Effect = 1.00 |
| Cmax | AUC | Cmin |
| Alprazolam | 0.5 single dose | 12 | 1.09 (1.03, 1.15) | 1.34 (1.15, 1.55) | NA |
| Amlodipine | 5 single dose | 14 | 1.26 (1.11, 1.44) | 2.57 (2.31,2.86) | NA |
| Atazanavir/ ritonavira | Atazanavir 300 and ritonavir 100 once daily in the evening | 12 | 1.02 (0.92, 1.13 )b | 1.19 (1.11, 1.2 8 )b | 1.68 (1.44, 1.95 )b |
| Buprenorphine | Buprenorphine: 4 to 24 once | 10 | 2.18 (1.78, 2.68)c | 2.07 (1.78, 2.40)c | 3.12 (2.29, 4.27)c |
| Norbuprenorphine | daily and Naloxone 1 to 6 once daily | | 2.07 (1.42, 3.01)c | 1.84 (1.30,2.60)c | 2.10 (1.49, 2.97)c |
| Naloxone | 1.18 (0.81, 1.73) | 1.28 (0.92, 1.79)c | NA |
| Carbamazepine | 200 once daily followed by 200 twice daily | 12 | 1.10 (1.07, 1.14) | 1.17 (1.13, 1.22) | 1.35 (1.27, 1.45) |
Carbamazepine’s metabolite, carbamazepine-10,11-epoxide (CBZE) | 0.84 (0.82, 0.87) | 0.75 (0.73, 0.77) | 0.57 (0.54,0.61) |
| Carisoprodol | 250 single dose | 14 | 0.54 (0.47, 0.63) | 0.62 (0.55,0.70) | NA |
| Carisoprodol's metabolite, mepobramate Cyclobenzaprine | 1.17 (1.10, 1.25) | 1.09 (1.03, 1.16) | NA |
| 5 single dose | 14 | 0.68 (0.61,0.75) | 0.60 (0.53,0.68) | NA |
| Cyclobenzaprine's metabolite norcyclobenzaprine Cyclosporine | 1.03 (0.87, 1.23) | 0.74 (0.64,0.85) | NA |
| 30 single dosed | 10 | 1.01 (0.85, 1.20)c | 5.82 (4.73, 7.14)c | 15.80 (13.81, 18.09)c |
| Darunavire | 800 once daily | 8 | 0.92 (0.87, 0.98)b | 0.76 (0.71, 0.82)b | 0.52 (0.47, 0.58)b |
| Darunavir/ ritonavirf | Darunavir 600 twice daily and ritonavir 100 once daily in the evening | 7 | 0.87 (0.79, 0.96)b | 0.80 (0.74, 0.86)b | 0.57 (0.48, 0.67)b |
| Darunavir/ ritonavirg | Darunavir 800 and ritonavir 100 once daily in the evening | 10 | 0.79 (0.70, 0.90)b | 1.34 (1.25, 1.43)b | 0.54 (0.48, 0.62)b |
| Diazepam | 2 single dose | 13 | 1.18 (1.07, 1.30) | 0.78 (0.73, 0.82) | NA |
| Diazepam's metabolite nordiazepam | 1.10 (1.03, 1.19) | 0.56 (0.45, 0.70) | NA |
| Ethinyl Estradiol | Ethinyl estradiol 0.035 and Norgestimate 0.25 once daily | 8 | 1.16 (0.90, 1.50) | 1.06 (0.96, 1.17) | 1.12 (0.94, 1.33) |
| Norelgestromin | 9 | 2.01 (1.77,2.29) | 2.60 (2.30,2.95) | 3.11 (2.51,3.85) |
| Norgestrel | 9 | 2.26 (1.91,2.67) | 2.54 (2.09, 3.09) | 2.93 (2.39, 3.57) |
| Everolimus | 0.75 single dose | 12 | 4.74 (4.29, 5.25) | 27.12 (24.5,30.1) | 16.10 (14.5, 17.9) |
| Furosemide | 20 single dose | 12 | 1.42 (1.17, 1.72) | 1.08 (1.00, 1.17) | NA |
| Ketoconazole | 400 once daily | 12 | 1.15 (1.09, 1.21) | 2.17 (2.05,2.29) | NA |
| Elydrocodone | 5 single dose | 15 | 1.27 (1.14, 1.40) | 1.90 (1.72,2.10) | NA |
| Lopinavir/ ritonavir | 400/100 twice daily | 6 | 0.87 (0.76, 0.99)b | 0.94 (0.81, 1.10)b | 1.15 (0.93, 1.42)b |
| Lopinavir/ ritonavirh | 800/200 once daily | 12 | 0.86 (0.80, 0.93)b | 0.94 (0.87, 1.01)b | 3.18 (2.49, 4.06)b |
| Omeprazole | 40 once daily | 11 | 0.62 (0.48, 0.80) | 0.62 (0.51,0.75) | NA |
| Pravastatin | 10 once daily | 12 | 1.37 (1.11, 1.69) | 1.82 (1.60,2.08) | NA |
| Rosuvastatin | 5 once daily | 11 | 7.13 (5.11,9.96) | 2.59 (2.09,3.21) | 0.59 (0.51,0.69) |
| Rilpivirine | 25 once daily(morning)i | 8 | 2.55(2.08,3.12) | 3.25(2.80, 3.77) | 3.62(3.12,4.21) |
| Sirolimus | 0.5 single dosej | 11 | 6.40 | 37.99 | 19.55 |
| (5.34, 7.68)c | (31.5, 45.8)c | (16.7, 22.9)c |
| Tacrolimus | 2 single dose | 12 | 3.99 | 57.13 | 16.56 |
| (3.21, 4.97)c | (45.53,71.69)c | (12.97,21.16)c |
a. Atazanavir plus 100 mg ritonavir administered in the evening, 12 hours after morning dose of VIEKIRA PAK. b. Atazanavir or darunavir or lopinavir parameters are reported. c. Dose normalized parameters reported. d. 30 mg cyclosporine was administered with VIEKIRA PAK in the test arm and 100 mg cyclosporine was administeredin the reference arm without VIEKIRA PAK. e. Darunavir administered with VIEKIRA PAK in the morning was compared to darunavir administered with 100 mg ritonavir in the morning. f. Darunavir administered with VIEKIRA PAK in the morning and with 100 mg ritonavir in the evening was compared to darunavir administered with 100 mg ritonavir in the morning and evening. g. Darunavir plus 100 mg ritonavir administered in the evening, 12 hours after morning dose of VIEKIRA PAK compared to darunavir administered with 100 mg ritonavir in the evening. h. Lopinavir/ritonavir administered in the evening, 12 hours after morning dose of VIEKIRA PAK. i. Similar increases were observed when rilpivirine was dosed in the evening with food or 4 hours after food. j. 0.5 mg sirolimus was administered with VIEKIRA PAK in the test arm and 2 mg sirolimus was administeredin the reference arm without VIEKIRA PAK. NA: not available/not applicable; CI: Confidence interval Doses of ombitasvir, paritaprevir, and ritonavir were 25 mg, 150 mg and 100 mg. Doses of dasabuvir were 250 mg or 400 mg (both doses showed similar exposures). Ombitasvir, paritaprevir and ritonavir were dosed once daily and dasabuvir was dosed twice daily in all the above studies except studies with ketoconazole and carbamazepine that used single doses. |
Microbiology
Mechanism Of Action
VIEKIRA PAK combines three direct-acting antiviral agents with distinct mechanisms of action and non-overlapping resistance profiles to target HCV at multiple steps in the viral lifecycle.
Ombitasvir
Ombitasvir is an inhibitor of HCV NS5A, which is essential for viral RNA replication and virion assembly. The mechanism of action of ombitasvir has been characterized based on cell culture antiviral activity and drug resistance mapping studies.
Paritaprevir
Paritaprevir is an inhibitor of the HCV NS3/4A protease which is necessary for the proteolytic cleavage of the HCV encoded polyprotein (into mature forms of the NS3, NS4A, NS4B, NS5A, and NS5B proteins) and is essential for viral replication. In a biochemical assay, paritaprevir inhibited the proteolytic activity of recombinant HCV genotype 1a and 1b NS3/4A protease enzymes with IC50 values of 0.18 nM and 0.43 nM, respectively.
Dasabuvir
Dasabuvir is a non-nucleoside inhibitor of the HCV RNA-dependent RNA polymerase encoded by the NS5B gene, which is essential for replication of the viral genome. In a biochemical assay, dasabuvir inhibited a panel of genotype 1a and 1b NS5B polymerases with median IC50 values of 2.8 nM (range 2.4 nM to 4.2 nM; n = 3) and 3.7 nM (range 2.2 nM to 10.7 nM; n = 4), respectively. Based on drug resistance mapping studies of HCV genotypes 1a and 1b, dasabuvir targets the palm domain of the NS5B polymerase, and is therefore referred to as a non-nucleoside NS5B-palm polymerase inhibitor.
Antiviral Activity
Ombitasvir
The EC50 values of ombitasvir against genotype 1a-H77 and 1b-Con1 strains in HCV replicon cell culture assays were 14.1 pM and 5 pM, respectively. The median EC50 values of ombitasvir against HCV replicons containing NS5A genes from a panel of genotype 1a and 1b isolates from treatment-naïve subjects were 0.68 pM (range 0.35 to 0.88 pM; n = 11) and 0.94 pM (range 0.74 to 1.5 pM; n = 11), respectively.
Paritaprevir
The EC50 values of paritaprevir against genotype 1a-H77 and 1b-Con1 strains in the HCV replicon cell culture assay were 1.0 nM and 0.21 nM, respectively. The median EC50 values of paritaprevir against HCV replicons containing NS3 genes from a panel of genotype 1a and 1b isolates from treatment-naïve subjects were 0.68 nM (range 0.43 nM to 1.87 nM; n = 11) and 0.06 nM (range 0.03 nM to 0.09 nM; n = 9), respectively.
Ritonavir
In HCV replicon cell culture assays, ritonavir did not exhibit a direct antiviral effect and the presence of ritonavir did not affect the antiviral activity of paritaprevir.
Dasabuvir
The EC50 values of dasabuvir against genotype 1a-H77 and 1b-Con1 strains in HCV replicon cell culture assays were 7.7 nM and 1.8 nM, respectively. The median EC values of dasabuvir against HCV replicons containing NS5B genes from a panel of genotype 1a and 1b isolates from treatment-naïve subjects were 0.6 nM (range 0.4 nM to 2.1 nM; n = 11) and 0.3 nM (range 0.2 nM to 2 nM; n = 10), respectively.
Combination Antiviral Activity
Evaluation of pairwise combinations of ombitasvir, paritaprevir, dasabuvir and ribavirin in HCV genotype 1 replicon cell culture assays showed no evidence of antagonism in antiviral activity.
Resistance
In Cell Culture
Exposure of HCV genotype 1a and 1b replicons to ombitasvir, paritaprevir or dasabuvir resulted in the emergence of drug resistant replicons carrying amino acid substitutions in NS5A, NS3, or NS5B, respectively. Amino acid substitutions in NS5A, NS3, or NS5B selected in cell culture or identified in Phase 2b and 3 clinical trials were phenotypically characterized in genotype 1a or 1b replicons.
For ombitasvir, in HCV genotype 1a replicons single NS5A substitutions M28T/V, Q30E/R, L31V, H58D, and Y93C/H/L/N reduced ombitasvir antiviral activity by 58- to 67,000-fold. In genotype 1b replicons, single NS5A substitutions L28T, L31F/V, and Y93H reduced ombitasvir antiviral activity by 8- to 661-fold. In general, combinations of ombitasvir resistance-associated substitutions in HCV genotype 1a or 1b replicons further reduced ombitasvir antiviral activity.
For paritaprevir, in HCV genotype 1a replicons single NS3 substitutions F43L, R155G/K/S, A156T, and D168A/E/F/H/N/V/Y reduced paritaprevir antiviral activity by 7- to 219-fold. An NS3 Q80K substitution in a genotype 1a replicon reduced paritaprevir antiviral activity by 3-fold. Combinations of V36M, Y56H, or E357K with R155K or D168 substitutions reduced the activity of paritaprevir by an additional 2- to 7-fold relative to the single R155K or D168 substitutions in genotype 1a replicons. In genotype 1b replicons single NS3 substitutions A156T and D168A/H/V reduced paritaprevir antiviral activity by 7- to 159-fold. The combination of Y56H with D168 substitutions reduced the activity of paritaprevir by an additional 16- to 26-fold relative to the single D168 substitutions in genotype 1b replicons.
For dasabuvir, in HCV genotype 1a replicons single NS5B substitutions C316Y, M414I/T, E446K/Q, Y448C/H, A553T, G554S, S556G/R, and Y561H reduced dasabuvir antiviral activity by 8- to 1,472-fold. In genotype 1b replicons, single NS5B substitutions C316H/N/Y, S368T, N411S, M414I/T, Y448C/H, A553V, S556G and D559G reduced dasabuvir antiviral activity by 5- to 1,569-fold.
In Clinical Studies
In a pooled analysis of subjects treated with regimens containing ombitasvir, paritaprevir, and dasabuvir with or without ribavirin (for 12 or 24 weeks) in Phase 2b and Phase 3 clinical trials, resistance analyses were conducted for 64 subjects who experienced virologic failure (20 with ontreatment virologic failure, 44 with post-treatment relapse). Treatment-emergent substitutions observed in the viral populations of these subjects are shown in Table 9. Treatment-emergent substitutions were detected in all 3 HCV drug targets in 30/57 (53%) HCV genotype 1a infected subjects, and 1/6 (17%) HCV genotype 1b infected subjects.
Table 9: Treatment-Emergent Amino Acid Substitutions in the Pooled Analysis of VIEKIRA PAK with and without Ribavirin Regimens (12- or 24-week durations) in Phase 2b and Phase 3 Clinical Trials
| Target | Emergent Amino Acid Substitutions | Genotype la N = 58a % (n) | Genotype lb N = 6 % (n) |
| NS3 | Any of the following NS3 substitutions: V36A/M/T, F43L, V55I, Y56H, Q80L, I132V, R155K, A156G, D168(any), P334S, S342P, E357K, V406A/I, T449I, P470S, V23A (NS4A) | 88(51) | 67(4) |
| V36A/M/Tb | 7(4) | - |
| V55Ib | 7(4) | - |
| Y56Hb | 10(6) | 50(3) |
| I132Vb | 7(4) | - |
| R155K | 16(9) | - |
| D168 (any)d | 72 (42) | 67(4) |
| D168V | 59(34) | 50(3) |
| P334Sb,c | 7(4) | - |
| E357Kb,c | 5(3) | 17(1) |
| V406A/Ib,c | 5(3) | - |
| T449Ib,c | 5(3) | - |
| P470Sb,c | 5(3) | - |
| NS4A V23Ab | - | 17(1) |
| F43Lb, Q80Lb, A156G, S342Pb,c | <5% | - |
| NS5A | Any of the following NS5A substitutions: K24R, M28A/T/V, Q30E/K/R, H/Q54Y, H58D/P/R, Y93C/H/N | 78(45) | 33(2) |
| K24R | 5(3) | - |
| M28A/T/V | 33(19) | - |
| Q30E/K/R | 47 (27) | - |
| H/Q54Y | - | 17(1) |
| H58D/P/R | 7(4) | - |
| Y93C/N | 5(3) | - |
| Y93H | - | 33(2) |
| NS5B | Any of the following NS5B substitutions: G307R, C316Y, M414I/T, E446K/Q, A450V, A553I/T/V, G554S, S556G/R, G558R, D559G/I/N/V, Y561H | 67(38) | 33(2) |
| C316Y | 4(2) | 17(1) |
| M414I | - | 17(1) |
| M414T | 5(3) | 17(1) |
| A553I/T/V | 7(4) | - |
| S556G/R | 39(22) | 17(1) |
| D559G/I/N/V | 7(4) | - |
| Y561H | 5(3) | - |
| G307R, E446K/Q, A450V, G554S, G558R | <5% | - |
a. N = 57 for the NS5B target. b. Substitutions were observed in combination with other emergent substitutions at NS3 position R155 or D168. c. Position located in NS3 helicase domain. d. D168A/F/H/I/L/N/T/V/Y. |
Persistence Of Resistance-Associated Substitutions
The persistence of ombitasvir, paritaprevir, and dasabuvir treatment-emergent amino acid substitutions in NS5A, NS3, and NS5B, respectively, was assessed in HCV genotype 1a-infected subjects in Phase 2 trials whose virus had at least 1 treatment-emergent resistance-associated substitution in the drug target, and with available data through at least 24 weeks post-treatment. Population and clonal nucleotide sequence analyses (assay sensitivity approximately 5-10%) were conducted to detect the persistence of viral populations with treatment-emergent substitutions.
For ombitasvir, viral populations with 1 or more resistance-associated treatment-emergent substitutions in NS5A persisted at detectable levels through at least Post-Treatment Week 24 in 24/24 (100%) subjects, and through Post-Treatment Week 48 in 18/18 (100%) subjects with available data.
For paritaprevir, viral populations with 1 or more treatment-emergent substitutions in NS3 persisted at detectable levels through at least Post- Treatment Week 24 in 17/29 (59%) subjects, and through Post-Treatment Week 48 in 5/22 (23%) subjects with available data. Resistance-associated variant R155K remained detectable in 5/8 (63%) subjects through Post-Treatment Week 24, and in 1/5 (20%) subjects through Post-Treatment Week 48. Resistance-associated D168 substitutions remained detectable in 6/22 (27%) subjects through Post-Treatment Week 24, and were no longer detectable through Post-Treatment Week 48.
For dasabuvir, viral populations with 1 or more treatment-emergent substitutions in NS5B persisted at detectable levels through at least Post- Treatment Week 24 in 11/16 (69%) subjects, and through Post-Treatment Week 48 in 8/15 (53%) subjects with available data. Treatment-emergent S556G persisted through Post-Treatment Week 48 in 6/9 (67%) subjects.
Among HCV genotype 1b infected subjects who experienced virologic failure with a regimen including ombitasvir and paritaprevir, a treatmentemergent NS5A Y93H substitution persisted through at least Post-Treatment Week 48 in 2/2 subjects, and a NS3 D168V treatment-emergent substitution persisted through Post-Treatment Week 24 in 2/4 subjects, but was no longer detectable through Post-Treatment Week 48 (0/4 subjects).
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-resistance-associated substitutions is unknown.
Effect Of Baseline HCV Polymorphisms On Treatment Response
A pooled analysis of subjects in the Phase 3 clinical trials of ombitasvir, paritaprevir, and dasabuvir with or without ribavirin was conducted to explore the association between baseline HCV NS5A, NS3, or NS5B resistance-associated polymorphisms and treatment outcome. Baseline samples from HCV genotype 1a infected subjects who experienced virologic failure (n=47), as well as samples from a subset of demographically matched subjects who achieved SVR (n=94), were analyzed to compare the frequencies of resistance-associated polymorphisms in these two populations. The NS3 Q80K polymorphism was detected in approximately 38% of subjects in this analysis and was enriched approximately 2-fold in virologic failure subjects compared to SVR-achieving subjects. Ombitasvir resistance-associated polymorphisms in NS5A (pooling data from all resistance-associated amino acid positions) were detected in approximately 22% of subjects in this analysis and similarly were enriched approximately 2-fold in virologic failure subjects. Dasabuvir resistance-associated polymorphisms in NS5B were detected in approximately 5% of subjects in this analysis and were not enriched in virologic failure subjects.
In contrast to the Phase 3 subset analysis, no association of NS3 or NS5A polymorphisms and treatment outcome was seen in an analysis of noncirrhotic HCV genotype 1a-infected subjects (n=174 for NS3 and n=183 for NS5A) who received ombitasvir, paritaprevir, and dasabuvir with or without ribavirin (for 12 or 24 weeks) in a Phase 2b trial.
Baseline HCV polymorphisms are not expected to have a substantial impact on the likelihood of achieving SVR when VIEKIRA PAK is used as recommended for HCV genotype 1a and 1b infected patients, based on the low virologic failure rates observed in clinical trials.
Cross-resistance
Cross-resistance is expected among NS5A inhibitors, NS3/4A protease inhibitors, and non-nucleoside NS5B-palm inhibitors by class. Dasabuvir retained full activity against HCV replicons containing a single NS5B L159F, S282T, or V321A substitution, which are associated with resistance or prior exposure to nucleos(t)ide analogue NS5B polymerase inhibitors. In clinical trials of VIEKIRA PAK, no subjects who experienced virologic failure had treatment-emergent substitutions potentially associated with resistance to nucleos(t)ide analogue NS5B polymerase inhibitors.
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. Similarly, the efficacy of VIEKIRA PAK has not been studied in subjects who have failed prior treatment with another NS5A inhibitor, NS3/4A protease inhibitor, or NS5B inhibitor.
Clinical Studies
Description Of Clinical Trials
Table 10 presents the clinical trial design including different treatment arms that were conducted with VIEKIRA PAK with or without ribavirin in subjects with chronic hepatitis C (HCV) genotype 1 (GT1) infection. For detailed description of trial design and recommended regimen and duration [see DOSAGE AND ADMINISTRATION and Clinical Studies].
Table 10: Clinical Trials Conducted with VIEKIRA PAK With or Without Ribavirin (RBV) in Subjects with Chronic HCV GT1 Infection
| Trial | Population | Study Arms and Duration (Number of Subjects Treated) |
| SAPPHIRE-I (double-blind) | GT1 (aandb) TNa without cirrhosis | - VIEKIRA PAK + RBV for 12 weeks (473)
- Placebo for 12 weeks (158)
|
| SAPPHIRE-II (double-blind) | GT1 (aandb) TEb without cirrhosis | - VIEKIRA PAK + RBV for 12 weeks (297)
- Placebo for 12 weeks (97)
|
| PEARL-II (open-label) | GTlb TE witliout cirrhosis | - VIEKIRA PAK + RBV for 12 weeks (88)
- VIEKIRA PAK for 12 weeks (91)
|
| PEARL-III (double-blind) | GTlb TN witliout cirrhosis | - VIEKIRA PAK + RBV for 12 weeks (210)
- VIEKIRA PAK for 12 weeks (209)
|
| PEARL-IV (double-blind) | GTla TN without cirrhosis | - VIEKIRA PAK + RBV for 12 weeks (100)
- VIEKIRA PAK for 12 weeks (205)
|
| TURQUOISE-II (open-label) | GT1 (aandb) TN & TE with compensated cirrhosis | - VIEKIRA PAK + RBV for 12 weeks (208)
- VIEKIRA PAK + RBV for 24 weeks (172)
|
| TURQUOISE-III (open-label) | GTlb TN & TE with compensated cirrhosis | - VIEKIRA PAK for 12 weeks (60)
|
a TN, treatment-naïve was defined as not having received any prior therapy for HCV infection. b TE, treatment-experienced subjects were defined as having failed to respond to prior treatment with pegIFN/RBV. |
VIEKIRA PAK with RBV was also evaluated in the following two studies:
- HCV GT1-infected liver transplant recipients (CORAL-I) [see Clinical Studies].
- Subjects with HCV GT1 co-infected with HIV-1 (TURQUOISE-I) [see Clinical Studies].
In all clinical trials, the ombitasvir, paritaprevir, ritonavir dose was 25/150/100 mg once daily and the dasabuvir dose was 250 mg twice daily. Doses of drugs in VIEKIRA PAK were not adjusted. For subjects who received RBV, the RBV 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. RBV dose adjustments were performed according to the RBV labeling.
In all clinical trials, sustained virologic response was defined as HCV RNA below the lower limit of quantification (<LLOQ) 12 weeks after the end of treatment (SVR12). Plasma HCV RNA levels were measured using the COBAS TaqMan HCV test (version 2.0), for use with the High Pure System, which has an LLOQ of 25 IU per mL. Outcomes for subjects not achieving an SVR12 were recorded as on-treatment virologic failure (VF), post-treatment virologic relapse through post-treatment Week 12 or failure due to other non-virologic reasons (e.g., premature discontinuation, adverse event, lost to follow-up, consent withdrawn).
Clinical Trial Results In Adults With Chronic HCV Genotype 1a And 1b Infection Without Cirrhosis
Subjects With Chronic HCV GT1a Infection Without Cirrhosis
Subjects with HCV GT1a infection without cirrhosis treated with VIEKIRA PAK with RBV for 12 weeks in SAPPHIRE-I and -II and in PEARLIV [see Clinical Studies] had a median age of 53 years (range: 18 to 70); 63% of the subjects were male; 90% were White; 7% were Black/African American; 8% were Hispanic or Latino; 19% had a body mass index of at least 30 kg per m ; 55% of patients were enrolled in US sites; 72% had IL28B (rs12979860) non-CC genotype; 85% had baseline HCV RNA levels of at least 800,000 IU per mL.
Table 11 presents treatment outcomes for HCV GT1a treatment-naïve and treatment-experienced subjects treated with VIEKIRA PAK with RBV for 12 weeks in SAPPHIRE-I, PEARL-IV and SAPPHIRE-II.
Treatment-naïve, HCV GT1a-infected subjects without cirrhosis treated with VIEKIRA PAK in combination with RBV for 12 weeks in PEARL-IV had a significantly higher SVR12 rate than subjects treated with VIEKIRA PAK alone (97% and 90% respectively; difference +7% with 95% confidence interval, +1% to +12%). VIEKIRA PAK alone was not studied in treatment-experienced subjects with GT1a infection.
In SAPPHIRE-I and SAPPHIRE-II, no placebo subject achieved a HCV RNA <25 IU/mL during treatment.
Table 11: SVR12 for HCV Genotype 1a-Infected Subjects without Cirrhosis Who Were Treatment-Naïve or Previously Treated with PegIFN/RBV
| VIEKIRA PAK with RBV for 12 Weeks % (n/N) |
| GTla treatment-naive |
| SAPPHIRF-I SVR12 | 96% (308/322) |
| Outcome for subjects without SVR12 |
| On-treatment VF | <1% (1/322) |
| Relapse | 2% (6/314) |
| Other | 2% (7/322) |
| PEARL-IV SVR12 | 97% (97/100) |
| Outcome for subjects without SVR12 |
| On-treatment VF | 1% (1/100) |
| Relapse | 1% (1/98) |
| Other | 1% (1/100) |
| GTla treatment-experienced |
| SAPPHTRE-TT SVR12 | 96% (166/173) |
| Outcome for subjects without SVR12 |
| On-treatment VF | 0% (0/173) |
| Relapse | 3% (5/172) |
| Other | 1% (2/173) |
| SVR12 by Prior peglFN Experience |
| Null Responder | 95% (83/87) |
| Partial Responder | 100% (36/36) |
| Relapser | 94% (47/50) |
Subjects With Chronic HCV GT1b Infection Without Cirrhosis
Subjects with HCV GT1b infection without cirrhosis were treated with VIEKIRA PAK with or without RBV for 12 weeks in PEARL-II and -III [see Clinical Studies]. Subjects had a median age of 52 years (range: 22 to 70); 47% of the subjects were male; 93% were White; 5% were Black/African American; 2% were Hispanic or Latino; 21% had a body mass index of at least 30 kg per m²; 21% of patients were enrolled in US sites; 83% had IL28B (rs12979860) non-CC genotype; 77% had baseline HCV RNA levels of at least 800,000 IU per mL.
The SVR rate for HCV GT1b-infected subjects without cirrhosis treated with VIEKIRA PAK without RBV for 12 weeks in PEARL-II (treatmentexperienced: null responder, n=32; partial responder, n=26; relapser, n=33) and PEARL-III (treatment-naïve, n=209) was 100%.
Clinical Trial Results In Adults With Chronic HCV Genotype 1a And 1b Infection And Compensated Cirrhosis
VIEKIRA PAK with and without ribavirin was evaluated in two clinical trials in patients with compensated cirrhosis.
TURQUOISE-II was an open-label trial that enrolled 380 HCV GT1-infected subjects with cirrhosis and mild hepatic impairment (Child-Pugh A) who were either treatment-naïve or did not achieve SVR with prior treatment with pegIFN/RBV. Subjects were randomized to receive VIEKIRA PAK in combination with RBV for either 12 or 24 weeks of treatment. Treated subjects had a median age of 58 years (range: 21 to 71); 70% of the subjects were male; 95% were White; 3% were Black/African American; 12% were Hispanic or Latino; 28% had a body mass index of at least 30 kg per m²; 43% of patients were enrolled in US sites; 82% had IL28B (rs12979860) non-CC genotype; 86% had baseline HCV RNA levels of at least 800,000 IU per mL; 69% had HCV GT1a infection, 31% had HCV GT1b infection; 42% were treatment-naïve, 36% were prior pegIFN/RBV null responders; 8% were prior pegIFN/RBV partial responders, 14% were prior pegIFN/RBV relapsers; 15% had platelet counts of less than 90 x 109 per L; 50% had albumin less than 4.0 mg per dL.
TURQUOISE-III was an open-label trial that enrolled 60 HCV GT1b-infected subjects with cirrhosis and mild hepatic impairment (Child-Pugh A) who were either treatment-naïve or did not achieve SVR with prior treatment with pegIFN/RBV. Subjects received VIEKIRA PAK without RBV for 12 weeks. Treated subjects had a median age of 61 years (range: 26 to 78); including 45% treatment-naïve and 55% pegIFN/RBV treatment experienced; 25% were ≥65 years; 62% were male; 12% were Black; 5% were Hispanic or Latino; 28% had a body mass index of at least 30 kg per m²; 40% of patients were enrolled in US sites; 22% had platelet counts of less than 90 x 109 per L; 17% had albumin less than 35 g/L; 92% had baseline HCV RNA levels of at least 800,000 IU per mL; 83% had IL28B (rs12979860) non-CC genotype.
Table 12 presents treatment outcomes for GT1a- and GT1b-infected treatment-naïve and treatment-experienced subjects. In GT1a infected subjects, the overall SVR12 rate difference between 24 and 12 weeks of treatment with VIEKIRA PAK with RBV was +6% with 95% confidence interval, -0.1% to +13% with differences varying by pretreatment history.
Table 12: TURQUOISE-II and TURQUOISE III: SVR12 for Chronic HCV Genotype 1-Infected Subjects with Compensated Cirrhosis Who Were Treatment-Naïve or Previously Treated with pegIFN/RBV
| GTla (TURQUOISE-II) | GTlb (TURQUOISE -III) |
| VIEKIRA PAK with RBV for 24 Weeks % (n/N) | VIEKIRA PAK with RBV for 12 Weeks % (n/N) | VIEKIRA PAK without RBV for 12 Weeks % (n/N) |
| SVR12 | 95% (115/121) | 89% (124/140) | 100% (60/60) |
| Outcome for subjects without SVR12 |
| On-treatment VF | 2% (3/121) | <1% (1/140) | 0 |
| Relapse | 1% (1/116) | 8% (11/135) | 0 |
| Other | 2% (2/121) | 3% (4/140) | 0 |
| SVR12 for Naive | 95% (53/56) | 92% (59/64) | 100% (27/27) |
| SVR12 by Prior peglFN Experience | | | 100% (33/33) |
| Null Responder | 93% (39/42) | 80% (40/50) | 100% (7/7) |
| Partial Responder | 100% (10/10) | 100% (11/11) | 100% (5/5) |
| Relapser | 100% (13/13) | 93% (14/15) | 100% (3/3) |
|
Effect Of Ribavirin Dose Reductions On SVR12
Seven percent of subjects (101/1551) treated with VIEKIRA PAK with RBV had a RBV dose adjustment due to a decrease in hemoglobin level; of these, 98% (98/100) achieved an SVR12.
Clinical Trial Of Selected Liver Transplant Recipients (CORAL-I)
VIEKIRA PAK with RBV was administered for 24 weeks to 34 HCV GT1-infected liver transplant recipients who were at least 12 months post transplantation at enrollment with normal hepatic function and mild fibrosis (Metavir fibrosis score F2 or lower). The initial dose of RBV was left to the discretion of the investigator with 600 to 800 mg per day being the most frequently selected dose range at initiation of VIEKIRA PAK and at the end of treatment.
Of the 34 subjects (29 with HCV GT1a infection and 5 with HCV GT1b infection) enrolled, (97%) achieved SVR12 (97% in subjects with GT1a infection and 100% of subjects with GT1b infection). One subject with HCV GT1a infection relapsed post-treatment.
Clinical Trial In Subjects With HCV/HIV-1 Co-infection (TURQUOISE-I)
In an open-label clinical trial 63 subjects with HCV GT1 infection co-infected with HIV-1 were treated for 12 or 24 weeks with VIEKIRA PAK in combination with RBV. Subjects were on a stable HIV-1 antiretroviral therapy (ART) regimen that included tenofovir disoproxil fumarate plus emtricitabine or lamivudine, administered with ritonavir boosted atazanavir or raltegravir. Subjects on atazanavir stopped the ritonavir component of their HIV-1 ART regimen upon initiating treatment with VIEKIRA PAK in combination with RBV. Atazanavir was taken with the morning dose of VIEKIRA PAK. The ritonavir component of the HIV-1 ART regimen was restarted after completion of treatment with VIEKIRA PAK and RBV.
Treated subjects had a median age of 51 years (range: 31 to 69); 24% of subjects were black; 81% of subjects had IL28B (rs12979860) non-CC genotype; 19% of subjects had compensated cirrhosis; 67% of subjects were HCV treatment-naïve; 33% of subjects had failed prior treatment with pegIFN/RBV; 89% of subjects had HCV genotype 1a infection.
The SVR12 rates were 91% (51/56) for subjects with HCV GT1a infection and 100% (7/7) for those with HCV GT1b infection. Of the 5 subjects who were non-responders, 1 experienced virologic breakthrough, 1 discontinued treatment, 1 experienced relapse and 2 subjects had evidence of HCV re-infection post-treatment.
One subject had confirmed HIV-1 RNA >400 copies/mL during the post-treatment period. This subject had no evidence of resistance to the ART regimen. No subjects switched their ART regimen due to loss of plasma HIV-1 RNA suppression.
Durability of Response
In an open-label clinical trial, 92% of subjects (526/571) who received various combinations of the direct acting antivirals included in VIEKIRA PAK with or without RBV achieved SVR12, and 99% of those who achieved SVR12 maintained their response through 48 weeks post-treatment (SVR48).