CLINICAL PHARMACOLOGY
Mechanism Of Action
VOSEVI is a fixed-dose combination of sofosbuvir,
velpatasvir, and voxilaprevir which are DAA agents against the hepatitis C
virus [see Microbiology].
Pharmacodynamics
Cardiac Electrophysiology
The effect of sofosbuvir 400 mg (recommended dosage) and
1200 mg (3 times the recommended dosage) on QTc interval was evaluated in an
active-controlled (moxifloxacin 400 mg) thorough QT trial. At a dose 3 times
the recommended dose, sofosbuvir does not prolong QTc to any clinically
relevant extent.
The effect of velpatasvir 500 mg (5 times the recommended
dosage) was evaluated in an active-controlled (moxifloxacin 400 mg) thorough QT
trial. At a dose 5 times the recommended dose, velpatasvir does not prolong QTc
interval to any clinically relevant extent.
The effect of voxilaprevir 900 mg (9 times the
recommended dosage) was evaluated in an active-controlled (moxifloxacin 400 mg)
thorough QT trial. At a dose 9 times the recommended dose, voxilaprevir does
not prolong QTc interval to any clinically relevant extent.
Pharmacokinetics
The pharmacokinetic properties of the components of
VOSEVI are provided in Table 4. The multiple dose pharmacokinetic parameters of
sofosbuvir and its metabolite GS-331007, velpatasvir, and voxilaprevir are
provided in Table 5.
Table 4 : Pharmacokinetic Properties of the Components
of VOSEVI
|
Sofosbuvir |
Velpatasvir |
Voxilaprevir |
Absorption |
T max (h) |
2 |
4 |
4 |
Effect of food (relative to fasting)a |
↑ 64% to 144% |
↑ 40% to 166% |
↑ 112% to 435% |
Distribution |
% Bound to human plasma proteins |
61-65 |
>99 |
>99 |
Blood-to-plasma ratio |
0.7 |
0.5-0.7 |
0.5-0.8 |
Metabolism |
Metabolism |
Cathepsin A CES1 HINT1 |
CYP2B6 CYP2C8 CYP3A4 |
CYP3A4 |
Elimination |
Major route of elimination |
SOF: metabolism GS-331007b: glomerular filtration and active tubular secretion |
Biliary excretion |
Biliary excretion |
t½ (h)c |
SOF: 0.5 GS-331007b: 29 |
17 |
33 |
% Of dose excreted in urined |
80e |
0.4 |
0 |
% Of dose excreted in fecesd |
14 |
94 (77%f as parent) |
94 (40%f as parent) |
CES1 = carboxylesterase 1; HINT1 = histidine triad
nucleotide-binding protein 1.
a Values refer to geometric mean systemic exposure. VOSEVI should be
taken with food.
b GS-331007 is the primary circulating nucleotide metabolite of SOF.
c t½ values refer to median terminal plasma half-life.
d Single dose administration of [14C] SOF, [14C]
VEL, [14C] VOX in mass balance studies.
e Predominantly as GS-331007.
f Percent of dose. |
Table 5 : Multiple Dose Pharmacokinetic Parameters of
Sofosbuvir and its Metabolite, GS-331007, Velpatasvir, and Voxilaprevir
Following Oral Administration in HCV-Infected Adults
Parameter Mean (%CV) |
Sofosbuvira |
GS-331007b |
Velpatasvirc |
Voxilaprevird |
Cmax (nanogram per mL) |
678 (35.4) |
744 (28.3) |
311 (56.1) |
192 (85.8) |
AUCτ (nanogram•hr per mL) |
1665 (30.1) |
12834 (29.0) |
4041 (48.6) |
2577 (73.7) |
Ctrough (nanogram per mL) |
NA |
NA |
51 (64.7) |
47 (82.0) |
CV = coefficient of variation; NA = not applicable.
a From Population PK analysis, N = 1038
b From Population PK analysis, N = 1593
c From Population PK analysis, N = 1595
d From Population PK analysis, N = 1591 |
Sofosbuvir and GS-331007 AUC0-24 and Cmax were similar in
healthy adult subjects and subjects with HCV infection. Relative to healthy
subjects (N=137), velpatasvir AUC0-24 and Cmax were 41% lower and 39% lower,
respectively, in HCV-infected subjects. Relative to healthy subjects (N=63),
voxilaprevir AUC0-24 and Cmax were both 260% higher in HCV-infected subjects.
Sofosbuvir and GS-331007 AUCs are near dose-proportional
over the dose range of 200 mg to 1200 mg. Velpatasvir AUC increases in a
greater than proportional manner from 5 to 50 mg and in a less than
proportional manner from 50 to 450 mg in healthy volunteers. However,
velpatasvir exhibited near dose-proportional increase in exposures 25 mg to 150
mg in HCV-infected patients. Voxilaprevir AUC increases in a greater than
proportional manner over the dose range of 100 to 900 mg when administered with
food.
Specific Populations
Pediatric Patients
The pharmacokinetics of VOSEVI in pediatric patients has
not been established [see Use In Specific Populations].
Geriatric Patients
Population pharmacokinetic analysis in HCV-infected
subjects showed that within the age range (18 to 85 years) analyzed, age did
not have a clinically relevant effect on the exposure to sofosbuvir, GS-331007,
velpatasvir, or voxilaprevir [see Use In Specific Populations].
Patients With Renal Impairment
The pharmacokinetics of sofosbuvir were studied in
HCV-negative subjects with mild (eGFR between 50 to less than 80 mL/min/1.73 m²),
moderate (eGFR between 30 to less than 50 mL/min/1.73 m²), severe renal
impairment (eGFR less than 30 mL/min/1.73 m²), and subjects with ESRD requiring
hemodialysis following a single 400 mg dose of sofosbuvir. Relative to subjects
with normal renal function (eGFR greater than 80 mL/min/1.73 m²), the
sofosbuvir AUC0-inf was 61%, 107%, and 171% higher in subjects with mild,
moderate, and severe renal impairment, while the GS-331007 AUC0-inf was 55%,
88%, and 451% higher, respectively. In subjects with ESRD, relative to subjects
with normal renal function, sofosbuvir and GS-331007 AUC0-inf was 28% and 1280%
higher when sofosbuvir was dosed 1 hour before hemodialysis compared with 60%
and 2070% higher when sofosbuvir was dosed 1 hour after hemodialysis,
respectively. A 4-hour hemodialysis session removed approximately 18% of
administered dose of sofosbuvir [see DOSAGE AND ADMINISTRATION and Use
In Specific Populations].
The pharmacokinetics of velpatasvir were studied with a
single dose of 100 mg velpatasvir in HCV-negative subjects with severe renal
impairment (eGFR less than 30 mL/min by Cockcroft-Gault). No clinically
relevant differences in velpatasvir pharmacokinetics were observed between
healthy subjects and subjects with severe renal impairment.
The pharmacokinetics of voxilaprevir were studied with a
single dose of 100 mg voxilaprevir in HCV-negative subjects with severe renal
impairment (eGFR < 30 mL/min by Cockcroft-Gault). No clinically relevant
differences in voxilaprevir pharmacokinetics were observed between healthy
subjects and subjects with severe renal impairment.
Patients With Hepatic Impairment
The pharmacokinetics of sofosbuvir were studied following
7-day dosing of 400 mg sofosbuvir in HCV-infected subjects with moderate and
severe hepatic impairment (Child-Pugh B and C). Relative to subjects with
normal hepatic function, the sofosbuvir AUC0-24 was 126% and 143% higher in
subjects with moderate and severe hepatic impairment, respectively, while the
GS-331007 AUC0-24 was 18% and 9% higher, respectively. Population
pharmacokinetic analysis in HCV-infected subjects indicated that compensated
cirrhosis (Child-Pugh A) had no clinically relevant effect on the exposure of
sofosbuvir and GS-331007.
The pharmacokinetics of velpatasvir were studied with a
single dose of 100 mg velpatasvir in HCV-negative subjects with moderate and
severe hepatic impairment (Child-Pugh B and C). Velpatasvir plasma exposure
(AUCinf) was similar in subjects with moderate hepatic impairment, severe
hepatic impairment, and control subjects with normal hepatic function.
Population pharmacokinetic analysis in HCV-infected subjects indicated that
compensated cirrhosis (Child-Pugh A) had no clinically relevant effect on the
exposure of velpatasvir.
The pharmacokinetics of voxilaprevir were studied with a
single dose of 100 mg voxilaprevir in HCV-negative subjects with moderate and
severe hepatic impairment (Child-Pugh B and C). Relative to subjects with
normal hepatic function, the voxilaprevir AUCinf was 299% and 500% higher in
subjects with moderate and severe hepatic impairment, respectively. Population
pharmacokinetic analysis in HCV-infected subjects indicated that subjects with
compensated cirrhosis (Child-Pugh A) had 73% higher exposure of voxilaprevir
than those without cirrhosis [see DOSAGE AND ADMINISTRATION and Use In
Specific Populations].
Race And Gender
Population pharmacokinetics analysis in
HCV-infected subjects indicated that race and gender had no clinically relevant
effect on the exposure of sofosbuvir, GS-331007, velpatasvir, or voxilaprevir.
Drug Interaction Studies
After oral administration of VOSEVI,
sofosbuvir is rapidly absorbed and subject to extensive first-pass hepatic
extraction (hydrolysis followed by sequential phosphorylation) to form the
pharmacologically active triphosphate. In clinical pharmacology studies, both
sofosbuvir and the primary circulating metabolite GS-331007 (dephosphorylated
nucleotide metabolite) were monitored for purposes of pharmacokinetic analyses.
Sofosbuvir, velpatasvir, and voxilaprevir are substrates
of drug transporters P-gp and BCRP while GS-331007 is not. Voxilaprevir, and to
a lesser extent velpatasvir, are also substrates of OATP1B1 and OATP1B3. In
vitro, slow metabolic turnover of velpatasvir by CYP2B6, CYP2C8, and CYP3A4 and
of voxilaprevir by CYP1A2, CYP2C8, and primarily CYP3A4 was observed. Inducers
of P-gp and/or moderate to potent inducers of CYP2B6, CYP2C8, or CYP3A4 (e.g.,
St. John's wort, carbamazepine) may significantly decrease plasma
concentrations of sofosbuvir, velpatasvir, and/or voxilaprevir leading to
reduced therapeutic effect of VOSEVI [see CONTRAINDICATIONS, WARNINGS
AND PRECAUTIONS, and DRUG INTERACTIONS]. Coadministration with drugs
that inhibit P-gp and/or BCRP may increase sofosbuvir, velpatasvir, and/or
voxilaprevir plasma concentrations without increasing GS-331007 plasma
concentration. Coadministration with drugs that inhibit OATP may increase
voxilaprevir plasma concentrations. Drugs that inhibit CYP2B6, CYP2C8, or
CYP3A4 may increase plasma concentration of velpatasvir and/or voxilaprevir.
Sofosbuvir and GS-331007 are not inhibitors of drug
transporters P-gp, BCRP, OATP1B1, OATP1B3, or OCT1 and GS-331007 is not an
inhibitor of OAT1, OAT3, OCT2, or MATE1. Sofosbuvir and GS-331007 are not
inhibitors or inducers of CYP or UGT1A1 enzymes.
Velpatasvir is an inhibitor of drug transporters P-gp,
BCRP, OATP1B1, OATP1B3, and OATP2B1, and its involvement in drug interactions
with these transporters is primarily limited to the process of absorption. At
clinically relevant concentrations, velpatasvir is not an inhibitor of hepatic
transporters OATP1A2 or OCT1, renal transporters OCT2, OAT1, OAT3 or MATE1, or
CYP or UGT1A1 enzymes.
Voxilaprevir is an inhibitor of drug transporters P-gp,
BCRP, OATP1B1 and OATP1B3, and its involvement in drug interactions with these
transporters is primarily limited to the process of absorption. At clinically
relevant concentrations, voxilaprevir is not an inhibitor of hepatic
transporters OCT1, renal transporters OCT2, OAT1, OAT3 or MATE1, or CYP or
UGT1A1 enzymes.
The effects of coadministered drugs on the exposure of
sofosbuvir, GS-331007, velpatasvir, and voxilaprevir are shown in Table 6. The
effects of sofosbuvir, velpatasvir, voxilaprevir, sofosbuvir/velpatasvir, or
VOSEVI on the exposure of coadministered drugs are shown in Table 7.
Table 6 : Drug Interactions: Changes in
Pharmacokinetic Parameters for Sofosbuvir, GS-331007, Velpatasvir, and
Voxilaprevir in the Presence of the Coadministered Druga
Coadministered Drug |
Sofosbuvir (SOF)/ Velpatasvir (VEL)/ Voxilaprevir (VOX) |
N |
Geometric Mean Ratio (90% CI) of Sofosbuvir, GS-331007, Velpatasvir, and Voxilaprevir PK With/Without Coadministered Drug No Effect=1.00 |
Drug |
Dosage
(mg) |
Active Component |
Dosage (mg) |
Component |
Cmax |
AUC |
Cmin |
Atazanavir + ritonavir |
300+100 single dose |
SOF/VEL/ VOX |
400/100/100 single dose |
15 |
sofosbuvir |
1.29 (1.09, 1.52) |
1.40 (1.25, 1.57) |
NA |
GS-331007 |
1.05 (0.99, 1.12) |
1.25 (1.16, 1.36) |
NA |
velpatasvir |
1.29 (1.07, 1.56) |
1.93 (1.58, 2.36) |
NA |
voxilaprevir |
4.42 (3.65, 5.35) |
4.31 (3.76, 4.93) |
NA |
Cyclosporine |
600 single dose |
SOF |
400 single dose |
19 |
sofosbuvir |
2.54 (1.87, 3.45) |
4.53 (3.26, 6.30) |
NA |
GS-331007 |
0.60 (0.53, 0.69) |
1.04 (0.90, 1.20) |
NA |
VEL |
100 single dose |
12 |
velpatasvir |
1.56 (1.22, 2.01) |
2.03 (1.51, 2.71) |
NA |
VOX |
100 single dose |
25 |
voxilaprevir |
19.02 (14.12, 25.62) |
9.39 (7.37, 11.96) |
NA |
Darunavir + ritonavir +emtricitabine/ tenofovir DF |
800+100+ 200/300 once daily |
SOF/VEL/ VOX + VOX |
400/100/100 + 100 once daily |
29 |
sofosbuvir |
0.70 (0.62, 0.78) |
0.78 (0.73, 0.83) |
NA |
GS-331007 |
1.06 (1.01, 1.10) |
1.15 (1.12, 1.19) |
NA |
velpatasvir |
0.78 (0.73, 0.84) |
0.95 (0.88, 1.02) |
1.16 (1.07, 1.26) |
voxilaprevir |
1.72 (1.51, 1.97) |
2.43 (2.15, 2.75) |
4.00 (3.44, 4.65) |
Dolutegravir |
50 once daily |
SOF/VEL |
400/100 once daily |
24 |
sofosbuvir |
0.88 (0.80, 0.98) |
0.92 (0.85, 0.99) |
NA |
GS-331007 |
1.01 (0.93, 1.10) |
0.99 (0.97, 1.01) |
0.99 (0.97, 1.01) |
velpatasvir |
0.94 (0.86, 1.02) |
0.91 (0.84, 0.98) |
0.88 (0.82, 0.94) |
Efavirenz/ emtricitabine/ tenofovir DFb |
600/200/300 once daily |
SOF/VEL |
400/100 once daily |
14 |
sofosbuvir |
1.38 (1.14, 1.67) |
0.97 (0.83, 1.14) |
NA |
GS-331007 |
0.86 (0.80, 0.93) |
0.90 (0.85, 0.96) |
1.01 (0.95, 1.07) |
velpatasvir |
0.53 (0.43, 0.64) |
0.47 (0.39, 0.57) |
0.43 (0.36, 0.52) |
Elvitegravir/ cobicistat/ emtricitabine/ tenofovir alafenamidec |
150/150/200/10 once daily |
SOF/VEL/ VOX + VOX |
400/100/100 + 100 once daily |
29 |
sofosbuvir |
1.27 (1.09, 1.48) |
1.22 (1.12, 1.32) |
NA |
GS-331007 |
1.28 (1.25, 1.32) |
1.43 (1.39, 1.47) |
NA |
velpatasvir |
0.96 (0.89, 1.04) |
1.16 (1.06, 1.27) |
1.46 (1.30, 1.64) |
voxilaprevir |
1.92 (1.63, 2.26) |
2.71 (2.30, 3.19) |
4.50 (3.68, 5.50) |
Ketoconazole |
200 twice daily |
VEL |
100 single dose |
12 |
velpatasvir |
1.29 (1.02, 1.64) |
1.71 (1.35, 2.18) |
NA |
Methadone |
30 to 130 daily |
SOF |
400 once daily |
14 |
sofosbuvir |
0.95 (0.68, 1.33) |
1.30 (1.00, 1.69) |
NA |
GS-331007 |
0.73 (0.65, 0.83) |
1.04 (0.89, 1.22) |
NA |
Omeprazole |
20 once daily 2 hours prior to VOSEVI |
SOF/VEL/ VOX |
400/100/100 single dose |
34 |
sofosbuvir |
0.77 (0.65, 0.91) |
0.73 (0.67, 0.79) |
NA |
GS-331007 |
1.27 (1.20, 1.34) |
0.97 (0.94, 1.01) |
NA |
velpatasvir |
0.43 (0.38, 0.49) |
0.46 (0.41, 0.52) |
NA |
voxilaprevir |
0.76 (0.69, 0.85) |
0.80 (0.74, 0.87) |
NA |
20 once daily 4 hours after VOSEVI |
SOF/VEL/ VOX |
400/100/100 single dose |
34 |
sofosbuvir |
0.94 (0.83, 1.06) |
0.82 (0.77, 0.87) |
NA |
GS-331007 |
1.19 (1.13, 1.26) |
0.99 (0.97, 1.01) |
NA |
velpatasvir |
0.49 (0.43, 0.55) |
0.49 (0.43, 0.55) |
NA |
voxilaprevir |
1.08 (0.96, 1.22) |
0.95 (0.88, 1.03) |
NA |
Rifampin |
600 once daily |
SOF |
400 single dose |
17 |
sofosbuvir |
0.23 (0.19, 0.29) |
0.28 (0.24, 0.32) |
NA |
GS-331007 |
1.23 (1.14, 1.34) |
0.95 (0.88, 1.03) |
NA |
VEL |
100 single dose |
12 |
velpatasvir |
0.29 (0.23, 0.37) |
0.18 (0.15, 0.22) |
NA |
VOX |
100 single dose |
24 |
voxilaprevir |
0.91 (0.76, 1.10) |
0.27 (0.23, 0.31) |
NA |
600 single dose |
VEL |
100 single dose |
12 |
velpatasvir |
1.28 (1.05, 1.56) |
1.46 (1.17, 1.83) |
NA |
VOX |
100 single dose |
24 |
voxilaprevir |
11.10 (8.23, 14.98) |
7.91 (6.20, 10.09) |
NA |
Tacrolimus |
5 single dose |
SOF |
400 single dose |
16 |
sofosbuvir |
0.97 (0.65, 1.43) |
1.13 (0.81, 1.57) |
NA |
GS-331007 |
0.97 (0.83, 1.14) |
1.00 (0.87, 1.13) |
NA |
Voriconazole |
200 twice daily |
VOX |
100 single dose |
24 |
voxilaprevir |
1.13 (0.98, 1.31) |
1.84 (1.66, 2.03) |
NA |
NA = not available/not applicable, ND = not dosed.
a All interaction studies conducted in healthy volunteers.
b Administered as ATRIPLA® (efavirenz, emtricitabine, and tenofovir
DF fixed-dose combination).
c Administered as GENVOYA® (elvitegravir, cobicistat, emtricitabine,
and tenofovir alafenamide fixed-dose combination). |
No effect on the pharmacokinetic parameters of
sofosbuvir, GS-331007, velpatasvir, or voxilaprevir was observed with the
combination of emtricitabine, rilpivirine, and tenofovir alafenamide;
famotidine; gemfibrozil; or the combination of raltegravir, emtricitabine, and
tenofovir DF.
Table 7 : Changes in Pharmacokinetic Parameters for
Coadministered Drug in the Presence of Sofosbuvir, Velpatasvir, Voxilaprevir,
or VOSEVIa
Coadministered Drug |
Sofosbuvir (SOF)/ Velpatasvir (VEL)/ Voxilaprevir (VOX) |
N |
Geometric Mean Ratio (90% CI) of Coadministered Drug PK With/Without Sofosbuvir, Velpatasvir, Voxilaprevir, or VOSEVI No Effect=1.00 |
Drug |
Dosage (mg) |
Active Component |
Dosage (mg) |
Cmax |
AUC |
Cmin |
Atorvastatin |
40 single dose |
SOF/VEL |
400/100 once daily |
26 |
1.68 (1.49, 1.89) |
1.54 (1.45, 1.64) |
NA |
Cyclosporine |
600 single dose |
SOF |
400 single dose |
19 |
1.06 (0.94, 1.18) |
0.98 (0.85, 1.14) |
NA |
VEL |
100 single dose |
12 |
0.92 (0.82, 1.02) |
0.88 (0.78, 1.00) |
NA |
VOX |
100 single dose |
24 |
0.95 (0.88, 1.03) |
0.94 (0.84, 1.06) |
NA |
Dabigatran etexilate |
75 single dose |
SOF/VEL/ VOX + VOX |
400/100/100 + 100 once daily |
36 |
2.87 (2.61, 3.15) |
2.61 (2.41, 2.82) |
NA |
Darunavir + ritonavir + emtricitabine/ tenofovir DFb |
darunavir 800 once daily |
SOF/VEL/ VOX + VOX |
400/100/100 + 100 once daily |
29 |
0.89 (0.85, 0.94) |
0.86 (0.81, 0.91) |
0.66 (0.58, 0.74) |
ritonavir 100 once daily |
1.60 (1.47, 1.75) |
1.45 (1.35, 1.57) |
0.80 (0.72, 0.89) |
emtricitabine 200 once daily |
0.88 (0.82, 0.94) |
0.99 (0.96, 1.03) |
1.20 (1.15, 1.26) |
tenofovir DF 300 once daily |
1.48 (1.36, 1.61) |
1.39 (1.32, 1.46) |
1.47 (1.38, 1.56) |
Digoxin |
0.25 single dose |
VEL |
100 once daily |
21 |
1.88 (1.71, 2.08) |
1.34 (1.13, 1.60) |
NA |
Efavirenz/ emtricitabine/ tenofovir DFc |
efavirenz 600 once daily |
SOF/VEL |
400/100 once daily |
15 |
0.81 (0.74, 0.89) |
0.85 (0.80, 0.91) |
0.90 (0.85, 0.95) |
emtricitabine 200 once daily |
1.07 (0.98, 1.18) |
1.07 (1.00, 1.14) |
1.10 (0.97, 1.25) |
tenofovir DF 300 once daily |
1.77 (1.53, 2.04) |
1.81 (1.68, 1.94) |
2.21 (2.00, 2.43) |
Elvitegravir/cobicistat/ emtricitabine/tenofovir alafenamided |
elvitegravir 150 once daily |
SOF/VEL/ VOX + VOX |
400/100/100 + 100 once daily |
29 |
0.79 (0.75, 0.85) |
0.94 (0.88, 1.00) |
1.32 (1.17, 1.49) |
cobicistat 150 once daily |
1.23 (1.18, 1.28) |
1.50 (1.44, 1.58) |
3.50 (3.01, 4.07) |
emtricitabine 200 once daily |
0.87 (0.84, 0.91) |
0.96 (0.94, 0.99) |
1.14 (1.09, 1.20) |
tenofovir alafenamide 10 once daily |
0.79 (0.68, 0.92) |
0.93 (0.85, 1.01) |
NA |
Emtricitabine/ rilpivirine/tenofovir alafenamidee |
emtricitabine 200 once daily |
SOF/VEL/ VOX + VOX |
400/100/100 + 100 once daily |
30 |
0.88 (0.83, 0.93) |
0.93 (0.90, 0.96) |
1.07 (1.01, 1.14) |
rilpivirine 25 once daily |
0.79 (0.74, 0.84) |
0.80 (0.76, 0.85) |
0.82 (0.77, 0.87) |
tenofovir alafenamide 25 once daily |
1.32 (1.17, 1.48) |
1.52 (1.43, 1.61) |
NA |
Pravastatin |
40 single dose |
SOF/VEL/ VOX + VOX |
400/100/100 + 100 once daily |
19 |
1.89 (1.53, 2.34) |
2.16 (1.79, 2.60) |
NA |
Rosuvastatin |
10 single dose |
SOF/VEL/ VOX + VOX |
400/100/100 + 100 once daily |
19 |
18.88 (16.23, 21.96) |
7.39 (6.68, 8.18) |
NA |
Raltegravir + emtricitabine/ tenofovir DF |
emtricitabine 200 once daily |
SOF/VEL |
400/100 once daily |
30 |
1.08 (1.04, 1.12) |
1.05 (1.03, 1.07) |
1.02 (0.97, 1.08) |
tenofovir DF 300 once daily |
1.46 (1.39, 1.54) |
1.40 (1.34, 1.45) |
1.70 (1.61, 1.79) |
raltegravir 400 twice daily |
1.03 (0.74, 1.43) |
0.97 (0.73, 1.28) |
0.79 (0.42, 1.48) |
Tacrolimus |
5 single dose |
SOF |
400 once daily |
16 |
0.73 (0.59, 0.90) |
1.09 (0.84, 1.40) |
NA |
NA = not available/not applicable.
a All interaction studies conducted in healthy volunteers.
b Comparison based on exposures when administered as darunavir +
ritonavir + emtricitabine/tenofovir DF.
c Administered as ATRIPLA (efavirenz, emtricitabine, and tenofovir
DF fixed-dose combination).
d Administered as GENVOYA (elvitegravir, cobicistat, emtricitabine,
and tenofovir alafenamide fixed-dose combination).
e Administered as ODEFSEY® (emtricitabine, rilpivirine, and
tenofovir alafenamide fixed-dose combination). |
No effect on the pharmacokinetic parameters of the
following coadministered drugs was observed with VOSEVI (ethinyl
estradiol/norgestimate) or its components sofosbuvir/velpatasvir (dolutegravir)
or sofosbuvir (methadone).
Microbiology
Mechanism Of Action
Sofosbuvir is an inhibitor of the HCV NS5B RNA-dependent
RNA polymerase, which is required for viral replication. Sofosbuvir is a
nucleotide prodrug that undergoes intracellular metabolism to form the
pharmacologically active uridine analog triphosphate (GS-461203), which can be
incorporated into HCV RNA by the NS5B polymerase and acts as a chain
terminator. In a biochemical assay, GS-461203 inhibited the polymerase activity
of the recombinant NS5B from HCV genotype 1b, 2a, 3a, and 4a with an IC50 value
ranging from 0.36 to 3.3 μM. GS-461203 is neither an inhibitor of human
DNA and RNA polymerases nor an inhibitor of mitochondrial RNA polymerase.
Velpatasvir is an inhibitor of the HCV NS5A protein,
which is required for viral replication. Resistance selection in cell culture
and cross-resistance studies indicate velpatasvir targets NS5A as its mode of
action.
Voxilaprevir is a noncovalent, reversible inhibitor of
the 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 inhibition assay,
voxilaprevir inhibited the proteolytic activity of recombinant NS3/4A enzymes
from clinical isolates of HCV genotypes 1b and 3a with Ki values of 38 and 66
pM, respectively.
Antiviral Activity
In HCV replicon assays, sofosbuvir had median EC50 values
of 15-110 nM against full-length or chimeric laboratory isolates and clinical
isolates from subtypes 1a, 1b, 2a, 2b, 3a, 4a, 4d, 5a, and 6a. Velpatasvir had
median EC50 values of 0.002-0.13 nM against full-length or chimeric laboratory
isolates and clinical isolates from subtypes 1a, 1b, 2a, 2b, 3a, 4a, 4d, 4r,
5a, 6a, and 6e. Voxilaprevir had median EC50 values of 0.2-6.6 nM against
full-length or chimeric laboratory isolates and clinical isolates from subtypes
1a, 1b, 2a, 2b, 3a, 4a, 4d, 4r, 5a, 6a, 6e, and 6n.
Evaluation of sofosbuvir in combination with velpatasvir
or voxilaprevir, as well as the combination of velpatasvir and voxilaprevir,
showed no antagonistic effect in reducing HCV RNA levels in replicon cells.
Resistance
In Cell Culture
HCV replicons with reduced susceptibility to sofosbuvir
have been selected in cell culture for multiple genotypes including 1b, 2a, 2b,
3a, 4a, 5a and 6a. Reduced susceptibility to sofosbuvir was associated with the
nucleotide analog NS5B polymerase inhibitor resistance substitution, S282T, in
all replicon genotypes examined. An M289L substitution emerged along with the
S282T substitution in genotypes 2a, 5 and 6 replicons. Site-directed
mutagenesis of the S282T substitution in replicons of genotype 1 to 6 conferred
2-to 18-fold reduced susceptibility to sofosbuvir.
HCV genotype 1a, 1b, 2a, 3a, 4a, 5a, and 6a replicon
variants with reduced susceptibility to velpatasvir were selected in cell
culture. The replicon variants developed amino acid substitutions at NS5A inhibitor
resistance-associated positions 24, 28, 30, 31, 32, 58, 92, and 93. Phenotypic
analysis of site-directed mutant replicons of the selected NS5A substitutions
showed that single Y93H/N and the combination of L31V + Y93H/N in genotype 1a,
the combination of L31V + Y93H in genotype 1b, the single substitution Y93H/S
in genotype 3a, and single substitutions L31V and P32A/L/Q/R in genotype 6
conferred greater than 100-fold reduction in velpatasvir susceptibility. In the
genotype 2a replicon, the single substitutions F28S and Y93H showed 91-fold and
46-fold reduced susceptibility to velpatasvir, respectively. The single
substitution Y93H conferred 3-fold reduced susceptibility to velpatasvir in genotype
4a replicons. Combinations of these NS5A substitutions often showed greater
reductions in susceptibility to velpatasvir than single substitutions alone.
HCV genotype 1a, 1b, 2a, 3a, 4a, 5a, and 6a replicon
variants with reduced susceptibility to voxilaprevir were selected in cell culture.
Amino acid substitutions were selected at NS3/4A protease inhibitor
resistance-associated positions 41, 156, and 168. Site-directed mutagenesis of
NS3 resistance-associated substitutions showed that substitutions conferring a
greater than 100-fold reduction in voxilaprevir susceptibility were A156L/T in
genotype 1a, A156T/V in genotype 1b, A156L/V in genotype 2a, A156T/V in
genotype 3a, and A156L/T/V in genotype 4. Combinations of these NS3
substitutions often showed greater reductions in susceptibility to voxilaprevir
than single substitutions alone.
In Clinical Trials
Of the 263 NS5A inhibitor-experienced subjects treated
with VOSEVI for 12 weeks in POLARIS-1, 7 of 263 (3%) subjects (2 with genotype
1a, 4 with genotype 3a, and 1 with genotype 4d) did not achieve SVR12 and
qualified for resistance analysis; 6 relapsed and 1 experienced virologic
breakthrough. All the virologic failures had cirrhosis and all had a previous
DAA regimen containing sofosbuvir; 3 were previously treated with ledipasvir/sofosbuvir,
2 were previously treated with sofosbuvir/velpatasvir, and 2 were previously
treated with daclatasvir and sofosbuvir. Six of the 7 virologic failures had
baseline NS5A inhibitor resistance-associated substitutions at position 30 or
93. All 7 virologic failures had NS5A resistance-associated substitutions at
failure using a sensitivity threshold of 1% of the viral population.
Of the 2 genotype 1a virologic failure subjects, one
subject with virologic breakthrough at Week 12 had virus with the NS5A
resistance-associated substitution Q30T at baseline and failure and emergent
NS5A resistance-associated substitutions L31M and Y93H at breakthrough; the
other subject had virus with the NS5A resistance-associated substitution Y93N
at baseline and relapse and emergence of low-level K24R (1.2%) in NS5A and V36A
(2%) in NS3 at relapse.
Of the 4 genotype 3a virologic failure subjects, one
subject had virus with emergent NS5A resistance-associated substitution E92K.
Two subjects had virus with Y93H at relapse that was enriched from baseline.
The remaining subject had virus with the NS5A resistance-associated
substitution A30K at baseline and relapse and emergence of low-level Q41K (2%),
V55A (3%) and R155M (1%) substitutions in NS3 at relapse.
The genotype 4d subject who relapsed had virus with
emergent NS5A resistance-associated substitution Y93H.
No NS5B nucleotide analog inhibitor resistance-associated
substitutions emerged among the virologic failure subjects from POLARIS-1.
In POLARIS-4, of the 182 DAA-experienced subjects who had
not received an NS5A inhibitor treated with VOSEVI for 12 weeks, 1 subject
(genotype 1a) of 182 (1%) subjects relapsed and qualified for resistance
analysis. The NS5A resistance-associated substitution M28T (7.5%) emerged in
this subject at relapse. No NS3/4A protease inhibitor or nucleotide analog NS5B
inhibitor substitutions were observed in this subject at relapse.
Persistence Of Resistance-Associated Substitutions
No data are available on the persistence of sofosbuvir,
velpatasvir or voxilaprevir resistance-associated substitutions. NS5A inhibitor
resistance-associated substitutions observed with administration of other NS5A
inhibitors have been found to persist for longer than 1 year in most patients.
The long-term clinical impact of the emergence or persistence of virus
containing sofosbuvir, velpatasvir, or voxilaprevir resistance-associated
substitutions is unknown.
Effect Of Baseline HCV Variants On Treatment Response
Analyses were conducted to explore the association
between SVR12 rates and preexisting baseline NS3/4A protease inhibitor and NS5A
inhibitor resistance-associated substitutions for subjects in POLARIS-1 and
POLARIS-4. Amino acid positions considered in resistance analyses included NS3
positions 36, 41, 43, 54, 55, 56, 155, 156, and 168, and NS5A positions 24, 28,
30, 31, 58, 92, or 93. Baseline resistance-associated amino acid substitutions,
which may include natural polymorphisms or prior treatment-emergent
substitutions relative to subtype-specific references, were identified by next
generation sequencing analysis using a sensitivity threshold of 15% of the
viral population.
Overall, the presence of baseline NS3/4A protease
inhibitor, NS5A inhibitor, and nucleotide analog NS5B polymerase inhibitor
resistance-associated substitutions did not alter the SVR rates for
DAA-experienced subjects in the POLARIS-1 and POLARIS4 trials who received 12
weeks of VOSEVI. For subjects treated with VOSEVI for 12 weeks, SVR12 rates in
subjects with or without baseline NS3 and NS5A resistance-associated
substitutions in the POLARIS-1 and POLARIS-4 trials were all greater than or
equal to 97%.
In POLARIS 1, which included NS5A inhibitor-experienced
subjects, 79% (206/260) of subjects had baseline NS5A resistance-associated
substitutions across all genotypes. The most prevalent NS5A
resistance-associated substitutions were at primary resistance-associated amino
acid positions 30 (97/206; 47%), 31 (58/206; 28%) and 93 (103/206; 50%).
Fifty-five percent (n=113/206) of the subjects had a single NS5A
resistance-associated substitution, while 2 resistance-associated substitutions
were detected in 65/206 subjects (32%) and 3 or more were detected in 28/206
subjects (14%). Overall prevalence of NS3/4A protease inhibitor
resistance-associated substitutions across all genotypes was 15% (37/248). The
most prevalent NS3 resistance-associated substitutions were at positions 36
(5/17; 29%) and 168 (7/17; 41%) in genotype 1a and position 56 in genotype 1b
(8/12; 67%). Substitutions at positions 36, 56, or 168 were detected in 1-2
subjects for each genotype 2, 3 or 4.
In POLARIS-4, which included DAA-experienced subjects who
had not received an NS5A inhibitor, 32% (57/177) of subjects who received 12
weeks of VOSEVI had baseline NS5A inhibitor resistance-associated
substitutions. Most of the subjects had a single NS5A resistance-associated
substitution (n=40; 70%). The most prevalent NS5A resistance-associated
substitution was at amino acid position 31 (n=27; 47%). Overall prevalence of
baseline NS3/4A protease inhibitor resistance-associated substitutions was 12%
(21/169). The most prevalent NS3 resistance-associated substitutions were at
positions 55 (5/10) and 168 (3/10) in genotype 1a, position 56 in genotype 1b
(3/5) and genotype 2 (3/3), and at position 168 in genotype 4 (3/3).
SVR12 was achieved in 18 of 19 (95%) subjects who had
baseline nucleotide analog NS5B polymerase inhibitor resistance-associated
substitutions in POLARIS-1, including 2 subjects who had virus with the S282T
nucleotide analog NS5B polymerase inhibitor resistance-associated substitution
in addition to NS5A resistance-associated substitutions at baseline. In
POLARIS-4, a total of 14 subjects had virus with nucleotide analog NS5B
polymerase inhibitor resistance-associated substitutions at baseline and all
achieved SVR12.
Cross Resistance
Cross-resistance is possible between HCV NS3/4A protease
inhibitors and between HCV NS5A inhibitors by class. Sofosbuvir, velpatasvir,
and voxilaprevir were each active against substitutions associated with
resistance to other classes of DAAs with different mechanisms of actions (e.g.,
voxilaprevir was fully active against virus with NS5A resistance-associated
substitutions and nucleotide analog NS5B inhibitor resistance-associated
substitutions).
Clinical Studies
Description Of Clinical Trials
The efficacy of VOSEVI was evaluated in two Phase 3
trials in DAA-experienced subjects with genotype 1, 2, 3, 4, 5, or 6 HCV
infection without cirrhosis or with compensated cirrhosis, as summarized in
Table 8.
Table 8 : Trials Conducted With VOSEVI in
DAA-Experienced Subjects With HCV Infection
Trial |
Population |
Study Arms and Comparator Groups (Number of Subjects Treated) |
POLARIS-1 |
Genotype 1, 2, 3, 4, 5, or 6 NS5A inhibitor-experienceda, without cirrhosis or with compensated cirrhosis |
VOSEVI 12 weeks (263) Placebo 12 weeks (152) |
POLARIS-4 |
Genotype 1, 2, 3, or 4 DAA-experiencedb who have not received an NS5A inhibitor, without cirrhosis or with compensated cirrhosis |
VOSEVI 12 weeks (182) SOF/VEL 12 weeks (151) |
DAA: direct-acting antiviral; SOF: sofosbuvir; VEL:
velpatasvir
a In clinical trials, prior NS5A inhibitor experience included
daclatasvir, elbasvir, ledipasvir, ombitasvir, or velpatasvir.
b In clinical trials, prior treatment experience included sofosbuvir
with or without any of the following: peginterferon alfa/ribavirin, ribavirin,
HCV NS3/4A protease inhibitor (boceprevir, simeprevir, or telaprevir). |
Serum HCV RNA values were measured during the clinical
trials using the COBAS AmpliPrep/COBAS Taqman HCV test (version 2.0) with a
lower limit of quantification (LLOQ) of 15 IU/mL. Sustained virologic response
(SVR12), defined as HCV RNA less than LLOQ at 12 weeks after the cessation of
treatment, was the primary endpoint in both trials. Relapse is defined as HCV
RNA greater than or equal to LLOQ after end-of treatment response among
subjects who completed treatment. On-treatment virologic failure is defined as
breakthrough, rebound, or non-response.
Clinical Trials In HCV DAA-Experienced Subjects
NS5A Inhibitor-Experienced Adults Without Cirrhosis Or With
Compensated Cirrhosis (POLARIS-1)
POLARIS-1 was a randomized, double-blind,
placebo-controlled trial that evaluated 12 weeks of treatment with VOSEVI
compared with 12 weeks of placebo in DAA-experienced subjects with genotype 1,
2, 3, 4, 5, or 6 HCV infection without cirrhosis or with compensated cirrhosis
who previously failed a regimen containing an NS5A inhibitor. Subjects with
genotype 1 HCV infection were randomized 1:1 to each group. Subjects with
genotype 2, 3, 4, 5, or 6 HCV infection were enrolled to the VOSEVI group.
Randomization was stratified by the presence or absence of cirrhosis.
Demographics and baseline characteristics were generally
balanced across treatment groups. Of the 415 treated subjects, the median age
was 59 years (range: 27 to 84); 77% of the subjects were male; 81% were White;
14% were Black; 6% were Hispanic or Latino; 33% had a baseline body mass index
at least 30 kg/m²; the majority of subjects had genotype 1 (72%) or genotype 3
(19%) HCV infection; 82% had a non-CC IL28B genotype (CT or TT); 74% had
baseline HCV RNA levels at least 800,000 IU/mL; and 41% had compensated
cirrhosis. In the POLARIS-1 trial, prior DAA regimens contained the following
NS5A inhibitors: ledipasvir (51%), daclatasvir (27%), ombitasvir (11%),
velpatasvir (7%), and elbasvir (3%).
Table 9 presents the SVR12 by HCV genotype for the
POLARIS-1 trial. No subjects in the placebo group achieved SVR12.
Table 9 : POLARIS-1 Trial: Virologic Outcomes by HCV
Genotype in VOSEVI-Treated Subjects Without Cirrhosis or With Compensated
Cirrhosis (12 Weeks After Treatment)
|
VOSEVI 12 Weeks
(N=263) |
Total (all GTs)a
(N=263) |
GT-1 |
GT-2
(N=5) |
GT-3
(N=78) |
GT-4
(N=22) |
GT-5
(N=1) |
GT-6
(N=6) |
GT-1a
(N=101) |
GT-1b
(N=45) |
Totalb
(N=150) |
SVR12 |
96% (253/263) |
96% (97/101) |
100% (45/45) |
97% (146/150) |
100% (5/5) |
95% (74/78) |
91% (20/22) |
100% (1/1) |
100% (6/6) |
Outcome for Subjects without SVR |
On- Treatment Virologic Failure |
<1% (1/263) |
1% (1/101) |
0/45 |
1% (1/150) |
0/5 |
0/78 |
0/22 |
0/1 |
0/6 |
Relapsec |
2% (6/261) |
1% (1/100) |
0/45 |
1% (1/149) |
0/5 |
5% (4/78) |
5% (1/21) |
0/1 |
0/6 |
Otherd |
1% (3/263) |
2% (2/101) |
0/45 |
1% (2/150) |
0/5 |
0/78 |
5% (1/22) |
0/1 |
0/6 |
GT: genotype
a One subject with undetermined genotype achieved SVR12.
b Four subjects had GT-1 subtypes other than GT-1a or GT-1b; all 4
subjects achieved SVR12.
c The denominator for relapse is the number of subjects with HCV RNA
<LLOQ at the end-of-treatment assessment.
d Other includes subjects who discontinued due to adverse event,
lost to follow-up, or subject withdrawal. |
DAA-Experienced Adults Without Cirrhosis Or With
Compensated Cirrhosis Who Had Not Received An NS5A Inhibitor (POLARIS-4)
POLARIS-4 was a randomized, open-label trial that
evaluated 12 weeks of treatment with VOSEVI and 12 weeks of treatment with
SOF/VEL in subjects with genotype 1, 2, 3, or 4 HCV infection without cirrhosis
or with compensated cirrhosis who had previously failed a HCV DAA-containing
regimen that did not include an NS5A inhibitor. Subjects whose only DAA
exposure was an NS3/4A protease inhibitor were excluded. Subjects with genotype
1, 2, or 3 HCV infection were randomized 1:1 to each group. Randomization was
stratified by HCV genotype and by the presence or absence of cirrhosis.
Subjects with genotype 4 HCV infection were enrolled to the VOSEVI group. No
subjects with genotype 5 or 6 were enrolled.
Demographics and baseline characteristics were generally
balanced across treatment groups. Of the 333 treated subjects, the median age
was 58 years (range: 24 to 85); 77% of the subjects were male; 87% were White,
9% were Black; 8% were Hispanic or Latino; 35% had a baseline body mass index
at least 30 kg/m²; 81% had non-CC IL28B genotypes (CT or TT); 75% had baseline
HCV RNA levels at least 800,000 IU/mL; and 46% had compensated cirrhosis. In
the POLARIS-4 trial, prior DAA regimens contained sofosbuvir (85%) with the
following: peginterferon alfa and ribavirin or ribavirin (69%), HCV NS3/4A
protease inhibitor (boceprevir, simeprevir, or telaprevir; 15%) and
investigational DAA (<1%). Of the 15% of subjects without prior sofosbuvir
exposure, most received investigational HCV DAAs or approved HCV NS3/4A
protease inhibitors, with or without peginterferon alfa and ribavirin.
Treatment with VOSEVI for 12 weeks resulted in
numerically higher SVR12 rates than treatment with sofosbuvir/velpatasvir for
12 weeks in subjects with HCV genotype 1a and 3 infection. Comparable SVR12
rates were observed in subjects with HCV genotype 1b and 2 infection treated
with VOSEVI for 12 weeks or with sofosbuvir/velpatasvir for 12 weeks. No
comparison data are available for HCV genotypes 4, 5, and 6. Given these data,
the additional benefit of VOSEVI has not been shown over sofosbuvir/velpatasvir
for these genotypes and VOSEVI is only indicated for the treatment of HCV
genotypes 1a or 3 infection in adults who previously received sofosbuvir
without an NS5A inhibitor.
Table 10 presents the comparative virologic outcome data
for HCV genotype 1, 2, and 3 subjects with prior exposure to a
sofosbuvir-containing regimen.
Table 10 : POLARIS-4 Trial: Virologic Outcomes by HCV
Genotype in VOSEVI-Treated Subjects* and SOF/VEL-Treated Subjects* Without
Cirrhosis or With Compensated Cirrhosis (12 Weeks After Treatment)
‘Subjects with prior exposure to a SOF-containing regimen |
VOSEVI 12 Weeks
(N=139) |
SOF/VEL 12 Weeks
(N=125) |
Overall (Genotypes 1, 2, and 3) |
SVR12 |
97% (135/139) |
88% (110/125) |
Not achieving SVR12 |
On-treatment virologic failure |
0% (0/139) |
1% (1/125) |
Relapsea |
1% (1/139) |
10% (13/124) |
Otherb |
2% (3/139) |
1% (1/125) |
Genotype 1 |
SVR12 |
96% (52/54) |
85% (34/40) |
Not achieving SVR12 |
On-treatment virologic failure |
0% (0/54) |
0% (0/40) |
Relapsea |
2% (1/54) |
13% (5/40) |
Otherb |
2% (1/54) |
3% (1/40) |
Genotype 1a |
SVR12 |
97% (35/36) |
82% (23/28) |
Not achieving SVR12 |
On-treatment virologic failure |
0% (0/36) |
0% (0/28) |
Relapsea |
3% (1/36) |
18% (5/28) |
Otherb |
0% (0/36) |
0% (0/28) |
Genotype 1b |
SVR12 |
94% (17/18) |
92% (11/12) |
Not achieving SVR12 |
On-treatment virologic failure |
0% (0/18) |
0% (0/12) |
Relapsea |
0% (0/18) |
0% (0/12) |
Otherb |
6% (1/18) |
8% (1/12) |
Genotype 2 |
SVR12 |
100% (31/31) |
97% (32/33) |
Not achieving SVR12 |
On-treatment virologic failure |
0% (0/31) |
3% (1/33) |
Relapsea |
0% (0/31) |
0% (0/32) |
Otherb |
0% (0/31) |
0% (0/33) |
Genotype 3 |
SVR12 |
96% (52/54) |
85% (44/52) |
Not achieving SVR12 |
On-treatment virologic failure |
0% (0/54) |
0% (0/52) |
Relapsea |
0% (0/54) |
15% (8/52) |
Otherb |
4% (2/54) |
0% (0/52) |
a The denominator for relapse is the number of
subjects with HCV RNA <LLOQ at the end-of-treatment assessment.
b Other includes subjects who discontinued due to adverse event,
lost to follow-up, or subject withdrawal. |
In POLARIS-4, VOSEVI was administered for 12 weeks to 18
HCV genotype 4 subjects (with or without cirrhosis) who had prior exposure to a
SOF-containing regimen without an NS5A inhibitor. All subjects achieved SVR12.