CLINICAL PHARMACOLOGY
Mechanism Of Action
BIKTARVY is a fixed dose
combination of antiretroviral drugs bictegravir (BIC), emtricitabine (FTC), and
tenofovir alafenamide (TAF) [see Microbiology].
Pharmacodynamics
Cardiac Electrophysiology
In a thorough QT/QTc trial in
48 healthy subjects, BIC at doses 1.5 and 6 times the recommended dose did not
affect the QT/QTc interval and did not prolong the PR interval. In a thorough
QT/QTc trial in 48 healthy subjects, TAF at the recommended dose or at a dose 5
times the recommended dose, did not affect the QT/QTc interval and did not
prolong the PR interval. The effect of FTC on the QT interval is not known.
Effects On Serum Creatinine
Mean change from baseline in
serum creatinine in healthy subjects who received BIC 75 mg (1.5 times the
approved recommended dosage) once daily with food for 14 days was 0.1 mg per dL
on Days 7 and 14 compared to placebo. BIC did not have a significant effect on
the estimated creatinine clearance or on the actual glomerular filtration rate
(determined by the clearance of probe drug, iohexol).
Pharmacokinetics
The pharmacokinetic (PK)
properties of BIKTARVY components are provided in Table 4. The multiple dose PK
parameters of BIKTARVY components (based on population pharmacokinetic
analysis) are provided in Table 5.
Table 4 : Pharmacokinetic Properties of the Components
of BIKTARVY
|
Bictegravir (BIC) |
Emtricitabine (FTC) |
Tenofovir Alafenamide (TAF) |
Absorption |
Tmax (h)a |
2.0-4.0 |
1.5-2.0 |
0.5-2.0 |
Effect of high-fat meal (relative to fasting)b |
AUC ratio |
1.24 (1.16, 1.33) |
0.96 (0.93, 0.99) |
1.63 (1.43, 1.85) |
Cmax ratio |
1.13 (1.06, 1.20) |
0.86 (0.78, 0.93) |
0.92 (0.73, 1.14) |
Distribution |
% bound to human plasma proteins |
>99 |
<4 |
~80 |
Blood-to-plasma ratio |
0.64 |
0.6 |
1.0 |
Elimination |
t½ (h)c |
17.3 (14.8, 20.7) |
10.4 (9.0, 12.0) |
0.51 (0.45, 0.62)c |
Metabolism |
Metabolic pathway(s) |
CYP3A UGT1A1 |
Not significantly metabolized |
Cathepsin Ad (PBMCs) CES1 (hepatocytes) |
Excretion |
Major route of elimination |
Metabolism |
Glomerular filtration and active tubular secretion |
Metabolism |
% of dose excreted in urinee |
35 |
70 |
<1 |
% of dose excreted in fecese |
60.3 |
13.7 |
31.7 |
PBMCs=peripheral blood mononuclear cells;
CES1=carboxylesterase 1
aValues reflect administration of BIKTARVY with or without food.
bValues refer to geometric mean ratio [high-fat meal/ fasting] in PK
parameters and (90% confidence interval). High fat meal is approximately 800
kcal, 50% fat.
ct½ values refer to median (Q1, Q3) terminal plasma half-life.
Note that the active metabolite of TAF, tenofovir diphosphate, has a half-life
of 150-180 hours within PBMCs.
dIn vivo, TAF is hydrolyzed within cells to form tenofovir (major
metabolite), which is phosphorylated to the active metabolite, tenofovir
diphosphate. In vitro studies have shown that TAF is metabolized to tenofovir
by cathepsin A in PBMCs and macrophages; and by CES1 in hepatocytes.
eDosing in mass balance studies: single dose administration of [14C]
BIC; single dose administration of [14C] FTC after multiple dosing of FTC for
ten days; single dose administration of [14C] TAF. |
Table 5 : Multiple Dose PK
Parameters of BIC, FTC, and TAF Following OralAdministration of BIKTARVY in
HIV-Infected Adults
Parameter Mean (CV%) |
Bictegravir |
Emtricitabine |
Tenofovir Alafenamide |
Cmax (microgram per mL) |
6.15 (22.9) |
2.13 (34.7) |
0.121 (15.4) |
AUCtau (microgram•h per mL) |
102 (26.9) |
12.3 (29.2) |
0.142 (17.3) |
Ctrough (microgram per mL) |
2.61 (35.2) |
0.096 (37.4) |
NA |
CV=Coefficient of Variation;
NA=Not Applicable |
Specific Populations
Patients With Renal Impairment
No clinically relevant
differences in the pharmacokinetics of BIC, TAF, or its metabolite tenofovir
were observed between subjects with severe renal impairment (CLcr 15 to 29 mL
per minute estimated by Cockcroft-Gault method) and healthy subjects.
Patients With Hepatic
Impairment
Bictegravir
Clinically relevant changes in
the pharmacokinetics of BIC were not observed in subjects with moderate
(Child-Pugh Class B) hepatic impairment.
Emtricitabine
The pharmacokinetics of FTC has
not been studied in subjects with hepatic impairment; however, FTC is not
significantly metabolized by liver enzymes, so the impact of hepatic impairment
should be limited.
Tenofovir Alafenamide
Clinically relevant changes in
the pharmacokinetics of TAF or its metabolite tenofovir were not observed in
subjects with mild or moderate (Child-Pugh Class A and B) hepatic impairment [see
Use In Specific Populations].
Hepatitis B And/Or Hepatitis C
Virus Coinfection
The pharmacokinetics of BIC,
FTC, and TAF have not been evaluated in subjects coinfected with hepatitis B
and/or C virus.
Geriatric Patients
The pharmacokinetics of BIC,
FTC, and TAF have not been fully evaluated in the elderly (65 years of age and
older). Population pharmacokinetics analysis of HIV-infected subjects in Phase
3 trials of BIKTARVY showed that age did not have a clinically relevant effect
on exposures of BIC and TAF up to 74 years of age [see Use In Specific
Populations].
Pediatric Patients
Mean BIC Ctrough was lower in 50 pediatric patients aged
12 to less than 18 years and weighing at least 35 kg who received BIKTARVY in
Trial 1474 relative to adults following administration of BIKTARVY, but was not
considered clinically significant based on exposure-response relationships;
exposures of FTC and TAF in these pediatric patients were similar to those in
adults (Table 6).
Table 6 : Multiple Dose PK Parameters of BIC, FTC, and
TAF Following OralAdministration of BIKTARVY in HIV-Infected Pediatric Subjects
Aged12 to less than 18 years
Parameter Mean (CV%) |
Bictegravira |
Emtricitabineb |
Tenofovir Alafenamidea |
Cmax (microgram per mL) |
6.24 (27.1) |
2.69 (34.0) |
0.133 (70.2) |
AUCtau (microgram•h per mL) |
89.1 (31.0) |
13.6 (21.7) |
0.196 (50.3) |
Ctrough (microgram per mL) |
1.78 (44.4) |
0.064 (25.0) |
NA |
CV=Coefficient of Variation; NA=Not Applicable
aFrom Population PK analysis of cohort 1 of Trial 1474 (n=50 for
BIC; n=49 for TAF).
bFrom Intensive PK analysis of cohort 1 of Trial 1474 (n=24). |
Mean BIC Cmax, and exposures of FTC and TAF (AUCtau and Cmax)
achieved in 50 pediatric patients between the ages of 6 to less than 12 years
and weighing at least 25 kg who received BIKTARVY in Trial 1474 were higher
than exposures in adults; however, the increase was not considered clinically
significant as the safety profiles were similar in adult and pediatric patients
(Table 7) [see Use In Specific Populations].
Table 7 : Multiple Dose PK Parameters of BIC, FTC, and
TAF Following OralAdministration of BIKTARVY in HIV-Infected Pediatric Subjects
Aged6 to less than 12 years
Parameter Mean (CV%) |
Bictegravira |
Emtricitabineb |
Tenofovir Alafenamidea |
Cmax (microgram per mL) |
9.46 (24.3) |
3.89 (31.0) |
0.205 (44.6) |
AUCtau (microgram•h per mL) |
128 (27.8) |
17.6 (36.9) |
0.278 (40.3) |
Ctrough (microgram per mL) |
2.36 (39.0) |
0.227 (323) |
NA |
CV=Coefficient of Variation;
NA=Not Applicable
a From Population PK analysis of cohort 2 of Trial 1474 (n=50
for BIC; n=47 for TAF).
bFrom Intensive PK analysis of cohort 2 of Trial 1474 (n=25 except
n=24 for Ctrough). |
Race And Gender
No clinically relevant changes
in the pharmacokinetics of BIC, FTC, and TAF were observed based on gender or
race.
Drug Interaction Studies
As BIKTARVY is a complete
regimen for the treatment of HIV-1 infection, comprehensive information
regarding potential drug-drug interactions with other antiretroviral agents is
not provided.
BIC is a substrate of CYP3A and
UGT1A1.
BIC is an inhibitor of OCT2 and
MATE1. At clinically relevant concentrations, BIC is not an inhibitor of
hepatic transporters OATP1B1, OATP1B3, OCT1, BSEP, renal transporters OAT1 and
OAT3, or CYP (including CYP3A) or UGT1A1 enzymes.
TAF is a substrate of P-gp and
BCRP.
At clinically relevant
concentrations, TAF is not an inhibitor of drug transporters P-gp, BCRP,
hepatic transporters OATP1B1, OATP1B3, OCT1, BSEP, renal transporters OAT1,
OAT3, OCT2, MATE1, or CYP (including CYP3A) or UGT1A1 enzymes.
Drug interaction studies were
conducted with BIKTARVY or its components. Tables 8 and 9 summarize the
pharmacokinetic effects of other drugs on BIC and TAF, respectively. Table 10
summarizes the pharmacokinetic effects of BIKTARVY or its components on other
drugs.
Effect Of Other Drugs On BIKTARVY Components
Table 8 : Effect of Other Drugs on BICa
Coadministered Drug |
Dose of Coadministered Drug (mg) |
BIC (mg) |
Mean Ratio of BIC Pharmacokinetic Parameters (90% CI); No effect = 1.00 |
Cmax |
AUC |
Cmin |
Ledipasvir/ Sofosbuvir (fed) |
90/400 once daily |
75 once daily |
0.98
(0.94, 1.03) |
1.00
(0.97, 1.03) |
1.04
(0.99, 1.09) |
Rifabutin (fasted) |
300 once daily |
75 once daily |
0.80
(0.67, 0.97) |
0.62
(0.53, 0.72) |
0.44
(0.37, 0.52) |
Rifampin (fed) |
600 once daily |
75 single dose |
0.72
(0.67, 0.78) |
0.25
(0.22, 0.27) |
NA |
Sofosbuvir/ velpatasvir/ voxilaprevir (fed) |
400/100/100+100 voxilaprevirb once daily |
50 once daily |
0.98
(0.94, 1.01) |
1.07
(1.03, 1.10) |
1.10
(1.05, 1.17) |
Voriconazole (fasted) |
300 twice daily |
75 single dose |
1.09
(0.96, 1.23) |
1.61
(1.41, 1.84) |
NA |
Maximum strength antacid (simultaneous administration, fasted) |
20 mLc single dose (oral) |
50 single dose |
0.20
(0.16, 0.24) |
0.21
(0.18, 0.26) |
NA |
Maximum strength antacid (2 h after BIKTARVY fasted) |
20 mLc single dose (oral) |
50 single dose |
0.93
(0.88, 1.00) |
0.87
(0.81, 0.93) |
NA |
Maximum strength antacid (2 h before BIKTARVY fasted) |
20 mLc single dose (oral) |
50 single dose |
0.42
(0.33, 0.52) |
0.48
(0.38, 0.59) |
NA |
Maximum strength antacid (simultaneous administration, fedd) |
20 mLc single dose (oral) |
50 single dose |
0.51
(0.43, 0.62) |
0.53
(0.44, 0.64) |
NA |
Calcium carbonate (simultaneous administration, fasted) |
1200 single dose |
50 single dose |
0.58
(0.51, 0.67) |
0.67
(0.57, 0.78) |
NA |
Calcium carbonate (simultaneous administration, fedd) |
1200 single dose |
50 single dose |
0.90
(0.78, 1.03) |
1.03
(0.89, 1.20) |
NA |
Ferrous fumarate (simultaneous administration, fasted) |
324 single dose |
50 single dose |
0.29
(0.26, 0.33) |
0.37
(0.33, 0.42) |
NA |
Ferrous fumarate (simultaneous administration, fedd) |
324 single dose |
50 single dose |
0.75
(0.65, 0.87) |
0.84
(0.74, 0.95) |
NA |
NA= Not Applicable
a All interaction studies conducted in healthy volunteers.
b Study conducted with additional voxilaprevir 100 mg to achieve
voxilaprevir exposures expected in HCV-infected patients.
c Maximum strength antacid contained 80 mg aluminum hydroxide, 80 mg
magnesium hydroxide, and 8 mg simethicone, per mL.
d Reference treatment administered under fasted conditions. |
Table 9 : Effect of Other Drugs on TAFa
Coadministered Drug |
Dose of Coadministered Drug (mg) |
Tenofovir Alafenamide (mg) |
Mean Ratio of Tenofovir Alafenamide Pharmacokinetic Parameters (90% CI); No effect = 1.00 |
Cmax |
AUC |
Cmin |
Carbamazepine |
300 twice daily |
25 single doseb |
0.43
(0.36, 0.51) |
0.46
(0.40, 0.54) |
NA |
Ledipasvir/sofosbuvir |
90/400 once daily |
25 once daily |
1.17
(1.00, 1.38) |
1.27
(1.19, 1.34) |
NA |
Sofosbuvir/ velpatasvir/ voxilaprevir |
400/100/100 +100 voxilaprevirc once daily |
25 once daily |
1.28
(1.09, 1.51) |
1.57
(1.44, 1.71) |
NA |
NA= Not Applicable
a All interaction studies conducted in healthy volunteers.
b Study conducted with emtricitabine/tenofovir alafenamide.
c Study conducted with additional voxilaprevir 100 mg to achieve
voxilaprevir exposures expected in HCV-infected patients. |
Effect Of BIKTARVY Components On
Other Drugs
Table 10 : Effect of Components of BIKTARVY on Other
Drugsa
Coadministered Drug |
Dose of Coadministered Drug (mg) |
BIC (mg) |
TAF (mg) |
Mean Ratio of Coadministered Drug Pharmacokinetic Parameters (90% CI); No effect = 1.00 |
Cmax |
AUC |
Cmin |
Ledipasvir |
90/400 once daily |
75 once daily |
25 once daily |
0.85
(0.81, 0.90) |
0.87
(0.83, 0.92) |
0.90
(0.84, 0.96) |
Sofosbuvir |
1.11
(1.00, 1.24) |
1.07
(1.01, 1.13) |
NA |
GS-331007b |
1.10
(1.07, 1.13) |
1.11
(1.08, 1.14) |
1.02
(0.99, 1.06) |
Metformin |
500 twice daily |
50 once daily |
25 once daily |
1.28
(1.21, 1.36) |
1.39
(1.31, 1.48) |
1.36
(1.21, 1.53) |
Midazolam |
2 single dose |
50 once daily |
25 once daily |
1.03
(0.87, 1.23) |
1.15
(1.00, 1.31) |
NA |
Norelgestromin |
norgestimate 0.180/0.215/0.250 once daily / ethinyl estradiol 0.025 once daily |
75 once daily |
- |
1.23
(1.14, 1.32) |
1.08
(1.05, 1.10) |
1.10
(1.05, 1.15) |
Norgestrel |
1.15
(1.10, 1.21) |
1.13
(1.07, 1.19) |
1.14
(1.06, 1.22) |
Ethinyl estradiol |
1.15
(1.03, 1.27) |
1.04
(0.99, 1.10) |
1.05
(0.95, 1.14) |
Norelgestromin |
norgestimate 0.180/0.215/0.250 once daily / ethinyl estradiol 0.025 once daily |
- |
25 once daily c |
1.17
(1.07,1.26) |
1.12
(1.07,1.17) |
1.16
(1.08, 1.24) |
Norgestrel |
1.10
(1.02, 1.18) |
1.09
(1.01, 1.18) |
1.11
(1.03, 1.20) |
Ethinyl estradiol |
1.22
(1.15, 1.29) |
1.11
(1.07, 1.16) |
1.02
(0.92, 1.12) |
Sertraline |
50 single dose |
- |
10 once daily d |
1.14
(0.94, 1.38) |
0.93
(0.77, 1.13) |
NA |
Sofosbuvir |
400/100/100+ 100e once daily |
50 once daily |
25 once daily |
1.14
(1.04,1.25) |
1.09
(1.02, 1.15) |
NA |
GS-331007b |
1.03
(0.99,1.06) |
1.03
(1.00,1.06) |
1.01
(0.98, 1.05) |
Velpatasvir |
0.96
(0.91,1.01) |
0.96
(0.90, 1.02) |
0.94
(0.88, 1.01) |
Voxilaprevir |
|
|
|
0.90
(0.76, 1.06) |
0.91
(0.80, 1.03) |
0.97
(0.88, 1.06) |
NA= Not Applicable
a All interaction studies conducted in healthy volunteers.
b The predominant circulating nucleoside metabolite of sofosbuvir.
c Study conducted with emtricitabine/tenofovir alafenamide.
d Study conducted with
elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide.
e Study conducted with additional voxilaprevir 100 mg to achieve
voxilaprevir exposures expected in HCV-infected patients. |
Microbiology
Mechanism Of Action
Bictegravir
BIC inhibits the strand
transfer activity of HIV-1 integrase (integrase strand transfer inhibitor;
INSTI), an HIV-1 encoded enzyme that is required for viral replication.
Inhibition of integrase prevents the integration of linear HIV-1 DNA into host
genomic DNA, blocking the formation of the HIV-1 provirus and propagation of
the virus.
Emtricitabine
FTC, a synthetic nucleoside
analog of cytidine, is phosphorylated by cellular enzymes to form emtricitabine
5'-triphosphate. Emtricitabine 5'-triphosphate inhibits the activity of the
HIV-1 reverse transcriptase by competing with the natural substrate
deoxycytidine 5'-triphosphate and by being incorporated into nascent viral DNA
which results in chain termination. Emtricitabine 5'-triphosphate is a
weak inhibitor of mammalian DNA polymerases α, β, ε, and
mitochondrial DNA polymerase &gama;.
Tenofovir Alafenamide
TAF is a phosphonamidate
prodrug of tenofovir (2'-deoxyadenosine monophosphate analog). Plasma
exposure to TAF allows for permeation into cells and then TAF is
intracellularly converted to tenofovir through hydrolysis by cathepsin A.
Tenofovir is subsequently phosphorylated by cellular kinases to the active
metabolite tenofovir diphosphate. Tenofovir diphosphate inhibits HIV-1
replication through incorporation into viral DNA by the HIV reverse
transcriptase, which results in DNA chain-termination. Tenofovir diphosphate is
a weak inhibitor of mammalian DNA polymerases that include mitochondrial DNA
polymerase &gama; and there is no evidence of toxicity to mitochondria in cell
culture.
Antiviral Activity in Cell
Culture
The triple combination of BIC,
FTC, and TAF was not antagonistic with respect to antiviral activity in cell
culture.
Bictegravir
The antiviral activity of BIC
against laboratory and clinical isolates of HIV-1 was assessed in
lymphoblastoid cell lines, PBMCs, primary monocyte/macrophage cells, and CD4+
T-lymphocytes. In MT-4 cells (human lymphoblastoid T-cell line) acutely
infected with HIV-1 IIIB, the mean 50% effective concentration (EC50) was
2.4±0.4 nM, and the protein-adjusted EC95 value was 361 nM (0.162 micrograms
per mL). BIC displayed antiviral activity in activated PBMCs against clinical
isolates of HIV-1 representing groups M, N, and O, including subtypes A, B, C,
D, E, F, and G, with a median EC50 value of 0.55 nM (range <0.05 to 1.71
nM). The EC50 value against a single HIV-2 isolate was 1.1 nM.
Emtricitabine
The antiviral activity of FTC against laboratory and
clinical isolates of HIV-1 was assessed in T lymphoblastoid cell lines, the
MAGI-CCR5 cell line, and PBMCs. In PBMCs acutely infected with HIV-1 subtypes
A, B, C, D, E, F, and G, the median EC50 value for FTC was 9.5 nM (range 1 to
30 nM) and against HIV-2 was 7 nM.
Tenofovir Alafenamide
The antiviral activity of TAF against laboratory and
clinical isolates of HIV-1 subtype B was assessed in lymphoblastoid cell lines,
PBMCs, primary monocyte/macrophage cells and CD4-T lymphocytes. The EC50 values
for TAF ranged from 2.0 to 14.7 nM. TAF displayed antiviral activity in cell
culture against all HIV-1 groups (M, N, O), including subtypes A, B, C, D, E,
F, and G (EC50 values ranged from 0.1 to 12 nM) and strain specific activity
against HIV-2 (EC50 values ranged from 0.9 to 2.6 nM).
Resistance
In Cell Culture
Bictegravir
HIV-1 isolates with reduced susceptibility to BIC have
been selected in cell culture. In one selection with BIC, a virus pool emerged
expressing amino acid substitutions M50I and R263K in the HIV-1 integrase.
M50I, R263K, and M50I+R263K substitutions, when introduced into a wild-type
virus by site-directed mutagenesis, conferred 1.3-, 2.2-, and 2.9-fold reduced
susceptibility to BIC, respectively. In a second selection, emergence of amino
acid substitutions T66I and S153F was detected, and 0.4-, 1.9-, and 0.5-fold
reductions in BIC susceptibility were observed with T66I, S153F, and
T66I+S153F, respectively. In addition, S24G and E157K substitutions emerged
during the selection process.
Emtricitabine
HIV-1 isolates with reduced susceptibility to FTC were
selected in cell culture and in subjects treated with FTC. Reduced
susceptibility to FTC was associated with M184V or I substitutions in HIV-1 RT.
Tenofovir Alafenamide
HIV-1 isolates with reduced susceptibility to TAF were
selected in cell culture. HIV-1 isolates selected by TAF expressed a K65R
substitution in HIV-1 RT, sometimes in the presence of S68N or L429I
substitutions; in addition, a K70E substitution in HIV-1 RT was observed.
In Clinical Trials
In Subjects With No Antiretroviral Treatment History
Pooled genotypic resistance analyses were performed on
paired baseline and on-treatment HIV-1 isolates from subjects receiving
BIKTARVY through Week 48 in Trials 1489 and 1490 [see Clinical Studies] who
had HIV-1 RNA greater than or equal to 200 copies/mL at the time of confirmed
virologic failure, Week 48, or early study drug discontinuation. No specific
amino acid substitutions emerged consistently in the 8 treatment failure
subjects with evaluable genotypic resistance data and failed to establish an
association with genotypic BIC resistance. There were no treatment-emergent
NRTI resistance-associated substitutions detected in the 8 evaluated treatment
failure isolates. Phenotypic resistance analyses of failure isolates found
fold-changes in drug susceptibility below the biological or clinical cutoffs
for BIC, FTC, and TFV, compared to wild-type reference HIV-1.
In Virologically Suppressed Adult Subjects
In 2 switch trials, Trials 1844 and 1878 [see Clinical
Studies], of virologically suppressed HIV-1 infected subjects (n=572), only
one subject with virologic rebound in the resistance analysis population had IN
genotypic and phenotypic data, and 2 rebounders had RT genotypic and phenotypic
data. No subjects had HIV-1 with treatment-emergent genotypic or phenotypic
resistance to BIC, FTC, or TAF.
In Virologically Suppressed Pediatric Subjects
In Trial 1474 [see Clinical Studies], two of 50
subjects in cohort 1 were evaluated for the development of resistance through
Week 48; no amino acid substitutions known to be associated with resistance to
BIC, FTC, or TFV were detected. No subjects in cohort 2 met the criteria for
resistance analyses.
Cross-Resistance
Bictegravir
Cross-resistance has been observed among INSTIs. The
susceptibility of BIC was tested against 64 clinical isolates expressing known
INSTI resistance-associated substitutions listed by IAS-USA (20 with single
substitutions and 44 with 2 or more substitutions). Isolates with a single
INSTI-resistance substitution including E92Q, T97A, Y143C/R, Q148R, and N155H
showed less than 2-fold reduced susceptibility to BIC. All isolates (n=14) with
more than 2.5-fold reduced susceptibility to BIC (above the biological cutoff
for BIC) contained G140A/C/S and Q148H/R/K substitutions; the majority (64.3%,
9/14) had a complex INSTI resistance pattern with an additional
INSTI-resistance substitution L74M, T97A, or E138A/K. Of those evaluated
isolates containing G140A/C/S and Q148H/R/K substitutions in the absence of
additional INSTI-resistance substitutions, 38.5% (5/13) showed more than
2.5-fold reduction. In addition, site-directed mutant viruses with G118R
(dolutegravir and raltegravir treatment-emergent substitution) and G118R+T97A
had 3.4-and 2.8-fold reduced susceptibility to BIC, respectively.
BIC demonstrated equivalent antiviral activity with less
than 2-fold reductions in susceptibility against HIV-1 variants expressing
substitutions associated with resistance to NNRTIs, NRTIs, and PIs, compared
with the wild-type virus.
Emtricitabine
Cross-resistance has been observed among NRTIs.
FTC-resistant viruses with an M184V/I substitution in HIV-1 RT were
cross-resistant to lamivudine. HIV-1 isolates containing the K65R RT
substitution, selected in vivo by abacavir, didanosine, and tenofovir, demonstrated
reduced susceptibility to inhibition by FTC.
Tenofovir Alafenamide
Cross-resistance has been observed among NRTIs.
Tenofovir resistance substitutions K65R and K70E result
in reduced susceptibility to abacavir, didanosine, emtricitabine, lamivudine,
and tenofovir. HIV-1 with multiple thymidine analog substitutions (M41L, D67N,
K70R, L210W, T215F/Y, K219Q/E/N/R), or multinucleoside resistant HIV-1 with a
T69S double insertion mutation or with a Q151M substitution complex including
K65R, showed reduced susceptibility to TAF in cell culture.
Animal Toxicology And/Or Pharmacology
Minimal to slight infiltration of mononuclear cells in
the posterior uvea was observed in dogs with similar severity after three and
nine month administration of TAF; reversibility was seen after a three month
recovery period. No eye toxicity was observed in the dog at systemic exposures
of 7 (TAF) and 14 (tenofovir) times the exposure seen in humans with the
recommended daily dose of BIKTARVY.
Clinical Studies
Description Of Clinical Trials
The efficacy and safety of BIKTARVY were evaluated in the
trials summarized in Table 11.
Table 11 : Trials Conducted with BIKTARVY in Subjects
with HIV-1 Infection
Trial |
Population |
Trial Arms (N) |
Timepoint (Week) |
Trial1489a (NCT 02607930) |
Adults with no antiretroviral treatment history |
BIKTARVY (314) ABC/DTG/3TC (315) |
48 |
Trial 1490a (NCT 02607956) |
BIKTARVY (320) DTG + FTC/TAF(325) |
48 |
Trial 1844a (NCT 02603120) |
Virologically-suppressedc adults |
BIKTARVY (282) ABC/DTG/3TC (281) |
48 |
Trial 1878b (NCT 02603107) |
BIKTARVY (290) ATV or DRV (with cobicistat or ritonavir) plus either FTC/TDF or ABC/3TC (287) |
48 |
Trial 1474d (cohort 1) (NCT 02881320) |
Virologically-suppressedc adolescents between the ages of 12 to less than 18 years (at least 35 kg) |
BIKTARVY (50) |
48 |
Trial 1474d (cohort 2) (NCT 02881320) |
Virologically-suppressedc children between the ages of 6 to less than 12 years (at least 25 kg) |
BIKTARVY (50) |
24 |
aRandomized, double blind, active controlled
trial.
bRandomized, open label, active controlled trial.
cHIV-1 RNA less than 50 copies per mL.
dOpen label trial. |
Clinical Trial Results In HIV-1
Subjects With No Antiretroviral Treatment History
In Trial 1489, subjects were
randomized in a 1:1 ratio to receive either BIKTARVY (N=314) or ABC/DTG/3TC
(600 mg/50 mg/300 mg) (N=315) once daily. In Trial 1490, subjects were
randomized in a 1:1 ratio to receive either BIKTARVY (N=320) or DTG + FTC/TAF
(50 mg + 200 mg/25 mg) (N=325) once daily.
In Trial 1489, the mean age was 34 years (range 18â⬓71),
90% were male, 57% were White, 36% were Black, and 3% were Asian. 22% of patients
identified as Hispanic/Latino. The mean baseline plasma HIV-1 RNA was 4.4 log10
copies/mL (range 1.3â⬓6.5). The mean baseline CD4+ cell count was 464 cells per
mm³ (range 0â⬓1424) and 11% had CD4+ cell counts less than 200 cells per mm³.
16% of subjects had baseline viral loads greater than 100,000 copies per mL.
In Trial 1490, the mean age was 37 years (range 18â⬓77),
88% were male, 59% were White, 31% were Black, and 3% were Asian. 25% of
patients identified as Hispanic/Latino. The mean baseline plasma HIV-1 RNA was
4.4 log10 copies/mL (range 2.3â⬓6.6). The mean baseline CD4+ cell count was 456
cells per mm³ (range 2â⬓1636) and 12% had CD4+ cell counts less than 200 cells
per mm³. 19% of subjects had baseline viral loads greater than 100,000 copies
per mL.
In both trials, subjects were stratified by baseline
HIV-1 RNA (less than or equal to 100,000 copies per mL, greater than 100,000
copies per mL to less than or equal to 400,000 copies per mL, or greater than
400,000 copies per mL), by CD4 count (less than 50 cells per mm³, 50-199 cells
per mm³, or greater than or equal to 200 cells per mm³), and by region (US or
ex-US).
Treatment outcomes of Trials 1489 and 1490 through Week
48 are presented in Table 12.
Table 12 : Virologic Outcomes of Randomized Treatment
in Trials 1489 and1490 at Week 48a in Subjects with No
Antiretroviral Treatment History
|
Trial 1489 |
Trial 1490 |
BIKTARVY
(N=314) |
ABC/DTG/3TC
(N=315) |
BIKTARVY
(N=320) |
DTG + FTC/TAF
(N=325) |
HIV-1 RNA < 50 copies/mL |
92% |
93% |
89% |
93% |
Treatment Difference (95% CI) BIKTARVY vs. Comparator |
-0.6% (-4.8% to 3.6%) |
-3.5% (-7.9% to 1.0%) |
HIV-1 RNA ≥ 50 copies/mLb |
1% |
3% |
4% |
1% |
No Virologic Data at Week 48 Window |
7% |
4% |
6% |
6% |
Discontinued Study Drug Due to AE or Deathc |
0 |
1% |
1% |
1% |
Discontinued Study Drug Due to Other Reasons and Last Available HIV-1 RNA <50 copies/mLd |
5% |
3% |
3% |
4% |
Missing Data During Window but on Study Drug |
2% |
<1% |
2% |
1% |
a Week 48 window was between Day 295 and 378
(inclusive).
b Includes subjects who had ≥ 50 copies/mL in the Week 48
window; subjects who discontinued early due to lack or loss of efficacy;
subjects who discontinued for reasons other than an adverse event (AE), death
or lack or loss of efficacy and at the time of discontinuation had a viral
value of ≥ 50 copies/mL.
c Includes subjects who discontinued due to AE or death at any time
point from Day 1 through the time window if this resulted in no virologic data
on treatment during the specified window.
d Includes subjects who discontinued for reasons other than an AE,
death, or lack or loss of efficacy, e.g., withdrew consent, loss to follow-up,
etc. |
Treatment outcomes were similar
across subgroups by age, sex, race, baseline viral load, and baseline CD4+ cell
count.
In Trials 1489 and 1490, the mean increase from baseline
in CD4+ count at Week 48 was 233 and 229 cells per mm³ in the BIKTARVY and
ABC/DTG/3TC groups, respectively, and 180 and 201 cells per mm³ in the BIKTARVY
and DTG + FTC/TAF groups, respectively.
Clinical Trial Results In HIV-1 Virologically-Suppressed
Subjects Who Switched To BIKTARVY
In Trial 1844, the efficacy and safety of switching from
a regimen of DTG + ABC/3TC or ABC/DTG/3TC to BIKTARVY were evaluated in a
randomized, double-blind trial of virologically-suppressed (HIV-1 RNA less than
50 copies per mL) HIV-1 infected adults (N=563, randomized and dosed). Subjects
must have been stably suppressed (HIV-1 RNA less than 50 copies per mL) on
their baseline regimen for at least 3 months prior to trial entry and had no
history of treatment failure. Subjects were randomized in a 1:1 ratio to either
switch to BIKTARVY at baseline (N=282), or stay on their baseline
antiretroviral regimen (N=281). Subjects had a mean age of 45 years (range 20â⬓71),
89% were male, 73% were White, and 22% were Black. 17% of subjects identified
as Hispanic/Latino. The mean baseline CD4+ cell count was 723 cells per mm³ (range
124â⬓2444).
In Trial 1878, the efficacy and safety of switching from
either ABC/3TC or FTC/TDF (200/300 mg) plus ATV or DRV (given with either
cobicistat or ritonavir) to BIKTARVY were evaluated in a randomized, open-label
study of virologically-suppressed HIV-1 infected adults (N=577, randomized and
dosed). Subjects must have been stably suppressed on their baseline regimen for
at least 6 months, must not have been previously treated with any INSTI, and
had no history of treatment failure. Subjects were randomized in a 1:1 ratio to
either switch to BIKTARVY (N=290) or stay on their baseline antiretroviral
regimen (N=287). Subjects had a mean age of 46 years (range 20â⬓79), 83% were
male, 66% were White, and 26% were Black. 19% of subjects identified as
Hispanic/Latino. The mean baseline CD4+ cell count was 663 cells per mm³ (range
62â⬓2582). Subjects were stratified by prior treatment regimen. At screening,
15% of subjects were receiving ABC/3TC plus ATV or DRV (given with either
cobicistat or ritonavir) and 85% of subjects were receiving FTC/TDF plus ATV or
DRV (given with either cobicistat or ritonavir).
Treatment outcomes of Trials 1844 and 1878 through Week
48 are presented in Table 13.
Table 13 : Virologic Outcomes of Trials 1844 and 1878
at Week 48a in Virologically-Suppressed Subjects who Switched to
BIKTARVY
|
Trial 1844 |
Trial 1878 |
|
BIKTARVY
(N=282) |
ABC/DTG/3TC
(N=281) |
BIKTARVY
(N=290) |
ATV- or DRV-based regimenb
(N=287) |
HIV-1 RNA ≥ 50 copies/mLc |
1% |
<1% |
2% |
2% |
Treatment Difference (95% CI) |
0.7% (-1.0% to 2.8%) |
0.0% (-2.5% to 2.5%) |
HIV-1 RNA < 50 copies/mL |
94% |
95% |
92% |
89% |
No Virologic Data at Week 48 Window |
5% |
5% |
6% |
9% |
Discontinued Study Drug Due to AE or Death and Last Available HIV-1 RNA < 50 copies/mL |
2% |
1% |
1% |
1% |
Discontinued Study Drug Due to Other Reasons and Last Available HIV-1 RNA < 50 copies/mLd |
2% |
3% |
3% |
7% |
Missing Data During Window but on Study Drug |
2% |
1% |
2% |
2% |
a Week 48 window was between Day 295 and 378
(inclusive).
b ATV given with cobicistat or ritonavir or DRV given with
cobicistat or ritonavir plus either FTC/TDF or ABC/3TC.
c Includes subjects who had ≥ 50 copies/mL in the Week 48
window; subjects who discontinued early due to lack or loss of efficacy;
subjects who discontinued for reasons other than lack or loss of efficacy and
at the time of discontinuation had a viral value of ≥ 50 copies/mL.
d Includes subjects who discontinued for reasons other than an AE, death, or lack
or loss of efficacy, e.g., withdrew consent, loss to follow-up, etc. |
In Trial 1844, treatment outcomes between treatment
groups were similar across subgroups by age, sex, race, and region. The mean
change from baseline in CD4+ count at Week 48 was -31 cells per mm³ in subjects
who switched to BIKTARVY and 4 cells per mm³ in subjects who stayed on
ABC/DTG/3TC.
In Trial 1878, treatment outcomes between treatment
groups were similar across subgroups by age, sex, race, and region. The mean
change from baseline in CD4+ count at Week 48 was 25 cells per mm³ in patients
who switched to BIKTARVY and 0 cells per mm³ in patients who stayed on their
baseline regimen.
Clinical Trial Results In HIV-1 Infected Pediatric
Subjects Between The Ages Of 6 To Less Than 18 Years
In Trial 1474, an open-label, single arm trial the
efficacy, safety, and pharmacokinetics of BIKTARVY in HIV-1 infected pediatric
subjects were evaluated in virologicallysuppressed adolescents between the ages
of 12 to less than 18 years weighing at least 35 kg (N=50) and in
virologically-suppressed children between the ages of 6 to less than 12 years
weighing at least 25 kg (N=50).
Cohort 1: Virologically-Suppressed Adolescents (12 To
Less Than 18 Years; At Least 35 kg)
Subjects in cohort 1 treated with BIKTARVY once daily had
a mean age of 14 years (range: 12 to 17) and a mean baseline weight of 51.7 kg
(range: 35 to 123), 64% were female, 27% were Asian and 65% were black. At
baseline, median CD4+ cell count was 750 cells per mm³ (range: 337 to 1207),
and median CD4+% was 33% (range: 19% to 45%).
After switching to BIKTARVY, 98% (49/50) of subjects in
cohort 1 remained suppressed (HIV-1 RNA < 50 copies/mL) at Week 48. The mean
change from baseline in CD4+ cell count at Week 48 was -22 cells per mm³.
Cohort 2: Virologically-Suppressed Children (6 To Less
Than 12 Years; At Least 25 kg)
Subjects in cohort 2 treated with BIKTARVY once daily had
a mean age of 10 years (range: 6 to 11) and a mean baseline weight of 31.9 kg
(range: 25 to 69), 54% were female, 22% were Asian and 72% were black. At
baseline, median CD4+ cell count was 898 cells per mm³ (range 390 to 1991) and
median CD4+% was 37% (range: 19% to 53%).
After switching to BIKTARVY, 100% (50/50) of subjects in
cohort 2 remained suppressed (HIV-1 RNA < 50 copies/mL) at Week 24. The mean
change from baseline in CD4+ cell count at Week 24 was -24 cells per mm³.