CLINICAL PHARMACOLOGY
Mechanism Of Action
ATRIPLA is a fixed-dose combination of antiviral drugs EFV, FTC, and TDF [see
Microbiology ].
Pharmacodynamics
Cardiac Electrophysiology
Efavirenz
The effect of EFV on the QTc interval was evaluated in an open-label,
positive and placebo-controlled, fixed single sequence 3-period, 3-treatment crossover
QT study in 58 healthy subjects enriched for CYP2B6 polymorphisms. The mean Cmax of
EFV in subjects with CYP2B6 *6/*6 genotype following the administration of 600 mg
daily dose for 14 days was 2.25-fold the mean Cmax observed in subjects with CYP2B6
*1/*1 genotype. A positive relationship between EFV concentration and QTc
prolongation was observed. Based on the concentration-QTc relationship, the mean
QTc prolongation and its upper bound 90% confidence interval are 8.7 msec and
11.3 msec in subjects with CYP2B6*6/*6 genotype following the administration of
600 mg daily dose for 14 days [see WARNINGS AND PRECAUTIONS].
Pharmacokinetics
ATRIPLA
One ATRIPLA tablet is bioequivalent to one Sustiva tablet (600 mg) plus one
EMTRIVA® capsule (200 mg) plus one VIREAD® tablet (300 mg) following single-dose
administration to fasting healthy subjects (N=45).
Efavirenz
In HIV-1 infected subjects time-to-peak plasma concentrations were
approximately 3–5 hours and steady-state plasma concentrations were reached in 6–10
days. In 35 HIV-1 infected subjects receiving EFV 600 mg once daily, steady-state Cmax
was 12.9 ± 3.7 μM (mean ± SD), Cmin was 5.6 ± 3.2 μM, and AUC was 184 ± 73 μM·hr.
EFV is highly bound (approximately 99.5–99.75%) to human plasma proteins,
predominantly albumin. Following administration of 14C-labeled EFV, 14–34% of the
dose was recovered in the urine (mostly as metabolites) and 16–61% was recovered in
feces (mostly as parent drug). In vitro studies suggest CYP3A and CYP2B6 are the
major isozymes responsible for EFV metabolism. EFV has been shown to induce CYP
enzymes, resulting in induction of its own metabolism. EFV has a terminal half-life of
52–76 hours after single doses and 40–55 hours after multiple doses.
Emtricitabine
Following oral administration, FTC is rapidly absorbed, with peak plasma
concentrations occurring at 1–2 hours postdose. Following multiple dose oral
administration of FTC to 20 HIV-1 infected subjects, the steady-state plasma FTC Cmax
was 1.8 ± 0.7 μg/mL (mean ± SD) and the AUC over a 24-hour dosing interval was
10.0 ± 3.1 μg•hr/mL. The mean steady-state plasma trough concentration at 24 hours
postdose was 0.09 μg/mL. The mean absolute bioavailability of FTC was 93%. Less
than 4% of FTC binds to human plasma proteins in vitro, and the binding is independent
of concentration over the range of 0.02−200 μg/mL. Following administration of
radiolabelled FTC, approximately 86% is recovered in the urine and 13% is recovered
as metabolites. The metabolites of FTC include 3′-sulfoxide diastereomers and their
glucuronic acid conjugate. FTC is eliminated by a combination of glomerular filtration
and active tubular secretion with a renal clearance in adults with normal renal function
of 213 ± 89 mL/min (mean ± SD). Following a single oral dose, the plasma FTC half-life
is approximately 10 hours.
Tenofovir DF
Following oral administration of a single 300 mg dose of TDF to HIV-1
infected subjects in the fasted state, maximum serum concentrations (Cmax) were
achieved in 1.0 ± 0.4 hrs (mean ± SD) and Cmax and AUC values were 296 ± 90 ng/mL
and 2287 ± 685 ng•hr/mL, respectively. The oral bioavailability of tenofovir from TDF in
fasted subjects is approximately 25%. Less than 0.7% of tenofovir binds to human
plasma proteins in vitro, and the binding is independent of concentration over the range
of 0.01–25 μg/mL. Approximately 70−80% of the intravenous dose of tenofovir is
recovered as unchanged drug in the urine. Tenofovir is eliminated by a combination of
glomerular filtration and active tubular secretion, with a renal clearance in adults with
normal renal function of 243 ± 33 mL/min (mean ± SD). Following a single oral dose, the
terminal elimination half-life of tenofovir is approximately 17 hours.
Effects of Food on Oral Absorption
ATRIPLA has not been evaluated in the presence of food. Administration of EFV tablets
with a high-fat meal increased the mean AUC and Cmax of EFV by 28% and 79%,
respectively, compared to administration in the fasted state. Compared to fasted
administration, dosing of TDF and FTC in combination with either a high-fat meal or a
light meal increased the mean AUC and Cmax of tenofovir by 35% and 15%,
respectively, without affecting FTC exposures [see DOSAGE AND ADMINISTRATION and PATIENT INFORMATION].
Specific Populations
Race
Efavirenz
The pharmacokinetics of EFV in HIV-1 infected subjects appear to be similar
among the racial groups studied.
Emtricitabine
No pharmacokinetic differences due to race have been identified
following the administration of FTC.
Tenofovir DF
There were insufficient numbers from racial and ethnic groups other than
Caucasian to adequately determine potential pharmacokinetic differences among these
populations following the administration of TDF.
Gender
Efavirenz, Emtricitabine, and Tenofovir DF
EFV, FTC, and tenofovir pharmacokinetics
are similar in male and female subjects.
Pediatric Patients
Efavirenz
In an open-label trial in NRTI-experienced pediatric subjects (mean age
8 years, range 3−16 years), the pharmacokinetics of EFV in pediatric subjects were
similar to the pharmacokinetics in adults who received a 600 mg daily dose of EFV.
Based on mean steady-state predicted population pharmacokinetic modeling in
pediatric subjects weighing >40 kg receiving the 600 mg dose of EFV, Cmax was
6.57 μg/mL, Cmin was 2.82 μg/mL, and AUC(0-24) was 254.78 μM•hr.
Emtricitabine
The pharmacokinetics of FTC at steady state were determined in 27 HIV-
1 infected pediatric subjects 13 to 17 years of age receiving a daily dose of 6 mg/kg up
to a maximum dose of 240 mg oral solution or a 200-mg capsule; 26 of 27 subjects in
this age group received the 200-mg capsule. Mean ± SD Cmax and AUC were 2.7 ± 0.9
μg/mL and 12.6 ± 5.4 μg•hr/mL, respectively. Exposures achieved in pediatric subjects
12 to less than 18 years of age were similar to those achieved in adults receiving a once
daily dose of 200 mg.
Tenofovir DF
Steady-state pharmacokinetics of tenofovir were evaluated in 8 HIV-1
infected pediatric subjects (12 to less than 18 years). Mean ± SD Cmax and AUCtau are
0.38 ± 0.13 μg/mL and 3.39 ± 1.22 μg•hr/mL, respectively. Tenofovir exposure achieved
in these pediatric subjects receiving oral daily doses of TDF 300 mg was similar to
exposures achieved in adults receiving once-daily doses of TDF 300 mg.
Geriatric Patients
Pharmacokinetics of EFV, FTC, and tenofovir have not been fully evaluated in the
elderly (65 years of age and older) [see Use In Specific Populations].
Patients With Impaired Renal Function
Efavirenz
The pharmacokinetics of EFV have not been studied in subjects with renal
insufficiency; however, less than 1% of EFV is excreted unchanged in the urine, so the
impact of renal impairment on EFV elimination should be minimal.
Emtricitabine and Tenofovir DF
The pharmacokinetics of FTC and TDF are altered in
subjects with renal impairment. In subjects with creatinine clearance below 50 mL/min,
Cmax and AUC0-∞ of FTC and tenofovir were increased [see WARNINGS AND PRECAUTIONS].
Patients With Hepatic Impairment
Efavirenz
A multiple-dose trial showed no significant effect on EFV pharmacokinetics in
subjects with mild hepatic impairment (Child-Pugh Class A) compared with controls.
There were insufficient data to determine whether moderate or severe hepatic
impairment (Child-Pugh Class B or C) affects EFV pharmacokinetics [see WARNINGS AND PRECAUTIONS and Use In Specific Populations].
Emtricitabine
The pharmacokinetics of FTC have not been studied in subjects with
hepatic impairment; however, FTC is not significantly metabolized by liver enzymes, so
the impact of liver impairment should be limited.
Tenofovir DF
The pharmacokinetics of tenofovir following a 300 mg dose of TDF have
been studied in non-HIV infected subjects with moderate to severe hepatic impairment.
There were no substantial alterations in tenofovir pharmacokinetics in subjects with
hepatic impairment compared with unimpaired subjects.
Assessment of Drug Interactions
The drug interaction trials described were conducted with either ATRIPLA or the
components of ATRIPLA (EFV, FTC, or TDF) as individual agents.
Efavirenz
The steady-state pharmacokinetics of EFV and tenofovir were unaffected
when EFV and TDF were administered together versus each agent dosed alone.
Specific drug interaction trials have not been performed with EFV and NRTIs other than
tenofovir, lamivudine, and zidovudine. Clinically significant interactions would not be
expected based on NRTIs elimination pathways.
Efavirenz has been shown in vivo to cause hepatic enzyme induction, thus increasing
the biotransformation of some drugs metabolized by CYP3A and CYP2B6. In vitro studies have shown that EFV inhibited CYP isozymes 2C9 and 2C19 with Ki values
(8.5−17 μM) in the range of observed EFV plasma concentrations. In in vitro studies,
EFV did not inhibit CYP2E1 and inhibited CYP2D6 and CYP1A2 (Ki values 82–160 μM)
only at concentrations well above those achieved clinically. Coadministration of EFV
with drugs primarily metabolized by CYP2C9, CYP2C19, CYP3A or CYP2B6 isozymes
may result in altered plasma concentrations of the coadministered drug. Drugs which
induce CYP3A and CYP2B6 activity would be expected to increase the clearance of
EFV resulting in lowered plasma concentrations.
Drug interaction trials were performed with EFV and other drugs likely to be
coadministered or drugs commonly used as probes for pharmacokinetic interaction.
There was no clinically significant interaction observed between EFV and zidovudine,
lamivudine, azithromycin, fluconazole, lorazepam, cetirizine, or paroxetine. Single doses
of famotidine or an aluminum and magnesium antacid with simethicone had no effects
on EFV exposures. The effects of coadministration of EFV on Cmax, AUC, and Cmin are
summarized in Table 4 (effect of other drugs on EFV) and Table 5 (effect of EFV on
other drugs) see DRUG INTERACTIONS].
Table 4: Drug Interactions: Changes in Pharmacokinetic Parameters for EFV in the
Presence of the Coadministered Drug
|
Mean % Change of EFV Pharmacokinetic
Parametersa (90% CI) |
Coadministered
Drug |
Dose of
Coadminister
ed Drug (mg) |
EFV Dose
(mg) |
N |
Cmax |
AUC |
Cmin |
Lopinavir/
ritonavir |
400/100 mg
q12h × 9 days |
600 mg qd
× 9 days |
11,
12b |
↔ |
↓ 16
(↓ 38 to ↑ 15) |
↓ 16
(↓ 42 to ↑ 20) |
Nelfinavir |
750 mg q8h ×
7 days |
600 mg qd
× 7 days |
10 |
↓ 12
(↓ 32 to ↑13)c |
↓ 12
(↓ 35 to ↑ 18)c |
↓ 21
(↓ 53 to ↑ 33) |
Ritonavir |
500 mg q12h ×
8 days |
600 mg qd
× 10 days |
9 |
↑ 14
(↑ 4 to ↑ 26) |
↑ 21
(↑ 10 to ↑ 34) |
↑ 25
(↑ 7 to ↑ 46)c |
Boceprevir |
800 mg tid × 6
days |
600 mg qd
× 16 days |
NA |
↑11
(↑ 2 to ↑ 20) |
↑ 20
(↑ 15 to ↑ 26) |
NA |
Rifabutin |
300 mg qd ×
14 days |
600 mg qd
× 14 days |
11 |
↔ |
↔ |
↓ 12
(↓ 24 to ↑ 1) |
Rifampin |
600 mg ×
7 days |
600 mg qd
× 7 days |
12 |
↓ 20
(↓ 11 to ↓ 28) |
↓ 26
(↓ 15 to ↓ 36) |
↓ 32
(↓ 15 to ↓ 46) |
Artemether/
lumefantrine |
Artemether
20 mg/
lumefantrine
120 mg tablets
(6 4-tablet
doses
over 3 days) |
600 mg qd
×
26 days |
12 |
↔ |
↓17 |
NA |
Simvastatin |
40 mg qd × 4
days |
600 mg qd
× 15 days |
14 |
↓ 12
(↓ 28 to ↑ 8) |
↔ |
↓ 12
(↓ 25 to ↑ 3) |
Carbamazepine |
200 mg qd ×
3 days,
200 mg bid ×
3 days, then
400 mg qd ×
15 days |
600 mg qd
× 35 days |
14 |
↓ 21
(↓ 15 to ↓ 26) |
↓ 36
(↓ 32 to ↓ 40) |
↓ 47
(↓ 41 to ↓ 53) |
Diltiazem |
240 mg × 14
days |
600 mg qd
× 28 days |
12 |
↑ 16
(↑ 6 to ↑ 26) |
↑ 11
(↑ 5 to ↑ 18) |
↑ 13
(↑ 1 to ↑ 26) |
Voriconazole |
400 mg po
q12h × 1 day
then 200 mg
po q12h ×
8 days |
400 mg qd
× 9 days |
NA |
↑ 38d |
↑ 44d |
NA |
300 mg po
q12h
days 2−7 |
300 mg qd
× 7 days |
NA |
↓ 14e
(↓ 7 to ↓ 21) |
↔e |
NA |
400 mg po
q12h days 2−7 |
300 mg qd
× 7 days |
NA |
↔e |
↑ 17e
(↑ 6 to ↑ 29) |
NA |
NA = not available
a Increase = ↑; Decrease = ↓; No Effect = ↔
b Parallel-group design; N for EFV + lopinavir/ritonavir, N for EFV alone.
c 95% CI
d 90% CI not available
e Relative to steady-state administration of EFV (600 mg once daily for 9 days). |
No effect on the pharmacokinetic parameters of EFV was observed with the following
coadministered drugs: indinavir, saquinavir soft gelatin capsule, simeprevir,
ledipasvir/sofosbuvir, sofosbuvir, clarithromycin, itraconazole, atorvastatin, pravastatin,
or sertraline.
Table 5: Drug Interactions: Changes in Pharmacokinetic Parameters for
Coadministered Drug in the Presence of EFV
|
Mean % Change of Coadministered Drug
Pharmacokinetic
Parametersa (90% CI) |
Coadministered
Drug |
Dose of
Coadministered
Drug (mg) |
EFV Dose
(mg) |
N |
Cmax |
AUC |
Cmin |
Atazanavir |
400 mg qd with a
light meal d 1–20 |
600 mg qd
with a light
meal d 7–20 |
27 |
↓ 59
(↓ 49 to ↓ 67) |
↓ 74
(↓ 68 to ↓78) |
↓ 93
(↓ 90 to ↓ 95) |
400 mg qd d 1–6,
then 300 mg qd
d 7–20 with
ritonavir 100 mg
qd and a light
meal |
600 mg qd 2
h after
atazanavir
and ritonavir
d 7–20 |
13 |
↑ 14b
(↓ 17 to ↑ 58) |
↑ 39b
(↑ 2 to ↑ 88) |
↑ 48b
(↑ 24 to ↑ 76) |
300 mg
qd/ritonavir 100
mg qd d 1-10
(pm), then 400 mg
qd/ritonavir 100
mg qd d 11−24
(pm)
(simultaneous with
EFV) |
600 mg qd
with a light
snack
d 11−24 (pm) |
14 |
↑ 17
(↑ 8 to ↑ 27) |
↔ |
↓ 42
(↓ 31 to ↓ 51) |
Indinavir |
1000 mg q8h × 10
days |
600 mg qd ×
10 days |
20 |
|
|
|
After morning dose |
|
↔c |
↓ 33c
(↓ 26 to ↓ 39) |
↓ 39c
(↓ 24 to ↓ 51) |
After afternoon dose |
|
↔c |
↓ 37c
(↓ 26 to ↓ 46) |
↓ 52c
(↓ 47 to ↓ 57) |
After evening dose |
|
↓ 29c
(↓ 11 to ↓ 43) |
↓ 46c
(↓ 37 to ↓ 54) |
↓ 57c
(↓ 50 to ↓ 63) |
Lopinavir/
ritonavir |
400/100 mg q12h
× 9 days |
600 mg qd ×
9 days |
11,
7d |
↔e |
↓ 19e
(↓ 36 to ↑ 3) |
↓ 39e
(↓ 3 to ↓ 62) |
Nelfinavir |
750 mg q8h × 7
days |
600 mg qd ×
7 days
| 10 |
↑ 21
(↑ 10 to↑ 33) |
↑ 20
(↑ 8 to ↑ 34) |
↔ |
Metabolite
AG-1402 |
|
↓ 40
(↓ 30 to ↓ 48) |
↓ 37
(↓ 25 to ↓ 48) |
↓ 43
(↓ 21 to ↓ 59) |
Ritonavir |
500 mg q12h × 8
days |
600 mg qd ×
10 days |
11 |
|
|
|
|
After AM dose |
|
|
↑ 24 (↑ 12 to ↑ 38) |
↑ 18 (↑ 6 to ↑ 33) |
↑ 42 (↑ 9 to ↑ 86)f |
|
After PM dose |
|
|
↔ |
↔ |
↑ 24
(↑ 3 to ↑ 50)f |
Saquinavir
SGCg |
1200 mg q8h ×
10 days |
600 mg qd ×
10 days |
12 |
↓ 50
(↓ 28 to ↓ 66) |
↓ 62
(↓ 45 to ↓74) |
↓ 56
(↓ 16 to ↓ 77)f |
Maraviroc |
100 mg bid |
600 mg qd |
12 |
↓ 51
(↓ 37 to ↓ 62) |
↓ 45
(↓ 38 to ↓ 51) |
↓ 45
(↓ 28 to ↓ 57) |
Raltegravir |
400 mg single
dose |
600 mg qd |
9 |
↓ 36
(↓ 2 to ↓ 59) |
↓ 36
(↓ 20 to ↓ 48) |
↓ 21
(↓ 51 to ↑ 28) |
Boceprevir |
800 mg tid × 6
days |
600 mg qd ×
16 days |
NA |
↓ 8
(↓ 22 to ↑ 8) |
↓ 19
(↓ 11 to ↓ 25) |
↓ 44
(↓ 26 to ↓ 58) |
Simeprevir |
150 mg qd ×
14 days |
600 mg qd ×
14 days |
23 |
↓ 51
(↓ 46 to
↓ 56) |
↓ 71
(↓ 67 to
↓ 74) |
↓ 91
(↓ 88 to
↓ 92) |
Ledipasvir/
sofosbuvirk |
90/400 mg qd
× 14 days |
600 mg qd ×
14 days |
|
|
|
|
Ledipasvir |
|
|
15 |
↓ 34
(↓ 25 to ↓ 41) |
↓ 34
(↓ 25 to ↓ 41) |
↓ 34
(↓ 24 to ↓ 43) |
Sofosbuvir |
|
|
|
↔ |
↔ |
NA |
GS-331007l |
|
|
|
↔ |
↔ |
↔ |
Sofosbuvirm |
400 mg qd
single dose |
600 mg qd ×
14 days |
16 |
↓ 19
(↓ 40 to ↑ 10) |
↔ |
NA |
GS-331007l |
|
|
|
↓ 23
(↓ 16 to ↓ 30) |
↓ 16
(↓ 24 to ↓ 8) |
NA |
Sofosbuvir/
velpatasvirn |
400/100 mg qd ×
14 days |
600 mg qd ×
14 days |
14 |
|
|
|
Sofosbuvir |
|
|
↑ 38
(↑ 14 to ↑ 67) |
↔ |
NA |
GS-331007l |
|
|
↓ 14
(↓ 20 to ↓ 7) |
↔ |
↔ |
Velpatasvir |
|
|
↓ 47
(↓ 57 to ↓ 36) |
↓ 53
(↓ 61 to ↓ 43) |
↓ 57
(↓ 64 to ↓ 48) |
Clarithromycin |
500 mg q12h × 7
days |
400 mg qd ×
7 days |
11 |
↓ 26
(↓ 15 to ↓ 35) |
↓ 39
(↓ 30 to ↓ 46) |
↓ 53
(↓ 42 to ↓ 63) |
14-OH metabolite |
|
|
|
↑ 49
(↑ 32 to ↑ 69) |
↑ 34
(↑ 18 to ↑ 53) |
↑ 26
(↑ 9 to ↑ 45) |
Itraconazole |
200 mg q12h × 28
days |
600 mg qd ×
14 days |
18 |
↓ 37
(↓ 20 to ↓ 51) |
↓ 39
(↓ 21 to ↓ 53) |
↓ 44
(↓ 27 to ↓ 58) |
Hydroxyitraconazole |
|
|
|
↓ 35
(↓ 12 to ↓ 52) |
↓ 37
(↓ 14 to ↓ 55) |
↓ 43
(↓ 18 to ↓ 60) |
Posaconazole |
400 mg (oral
suspension) bid ×
10 and 20 days |
400 mg qd ×
10 and 20
days |
11 |
↓ 45
(↓ 34 to ↓ 53) |
↓ 50
(↓ 40 to ↓ 57) |
NA |
Rifabutin |
300 mg qd ×
14 days |
600 mg qd ×
14 days |
9 |
↓ 32
(↓ 15 to ↓ 46) |
↓ 38
(↓ 28 to ↓ 47) |
↓ 45
(↓ 31 to ↓ 56) |
Artemether/
lumefantrine |
Artemether 20
mg/lumefantrine
120 mg tablets (6
4-tablet doses
over 3 days) |
600 mg qd ×
26 days |
12 |
|
|
|
Artemether |
|
|
|
↓ 21 |
↓ 51 |
NA |
dihydroartemisinin |
|
|
|
↓ 38 |
↓ 46 |
NA |
lumefantrine |
|
|
|
↔ |
↓ 21 |
NA |
Atorvastatin |
10 mg qd × 4 days |
600 mg qd ×
15 days |
14 |
↓ 14
(↓ 1 to ↓ 26) |
↓ 43
(↓ 34 to ↓ 50) |
↓ 69
(↓ 49 to ↓ 81) |
Total active
(including
metabolites) |
|
|
|
↓ 15
(↓ 2 to ↓ 26) |
↓ 32
(↓ 21 to ↓ 41) |
↓ 48
(↓ 23 to ↓ 64) |
Pravastatin |
40 mg qd × 4 days |
600 mg qd ×
15 days |
13 |
↓ 32
(↓ 59 to ↑ 12) |
↓ 44
(↓ 26 to ↓ 57) |
↓ 19
(↓ 0 to ↓ 35) |
Simvastatin |
40 mg qd × 4 days |
600 mg qd ×
15 days |
14 |
↓ 72
(↓ 63 to ↓ 79) |
↓ 68
(↓ 62 to ↓ 73) |
↓ 45
(↓ 20 to ↓ 62) |
Total active
(including
metabolites) |
|
|
|
↓ 68
(↓ 55 to ↓ 78) |
↓ 60
(↓ 52 to ↓ 68) |
NAh |
Carbamazepine |
200 mg qd ×
3 days, 200 mg
bid × 3 days, then
400 mg qd ×
29 days |
600 mg qd ×
14 days |
12 |
↓ 20
(↓ 15 to ↓ 24) |
↓ 27
(↓ 20 to ↓ 33) |
↓ 35
(↓ 24 to ↓ 44) |
Epoxide metabolite |
|
|
|
↔ |
↔ |
↓ 13
(↓ 30 to ↑ 7) |
Diltiazem |
240 mg × 21 days |
600 mg qd ×
14 days |
13 |
↓ 60
(↓ 50 to ↓ 68) |
↓ 69
(↓ 55 to ↓ 79) |
↓ 63
(↓ 44 to ↓ 75) |
Desacetyl diltiazem |
|
|
|
↓ 64
(↓ 57 to ↓ 69) |
↓ 75
(↓ 59 to ↓ 84) |
↓ 62
(↓ 44 to ↓ 75) |
N-monodesmethyl
diltiazem |
|
|
|
↓ 28 (↓ 7 to ↓ 44) |
↓ 37 (↓ 17 to ↓ 52) |
↓ 37 (↓ 17 to ↓ 52) |
Ethinyl estradiol/
norgestimate |
0.035 mg/0.25 mg
× 14 days |
600 mg qd ×
14 days |
|
|
|
|
Ethinyl estradiol |
|
|
21 |
↔ |
↔ |
↔ |
Norelgestromin |
|
|
21 |
↓ 46
(↓ 39 to ↓ 52) |
↓ 64
(↓ 62 to ↓ 67) |
↓ 82
(↓ 79 to ↓ 85) |
Levonorgestrel |
|
|
6 |
↓ 80
(↓ 77 to ↓ 83) |
↓ 83
(↓ 79 to ↓ 87) |
↓ 86
(↓ 80 to ↓ 90) |
Methadone |
Stable
maintenance 35–
100 mg daily |
600 mg qd ×
14–21 days |
11 |
↓ 45
(↓ 25 to ↓ 59) |
↓ 52
(↓ 33 to ↓ 66) |
NA |
Bupropion |
150 mg single
dose (sustainedrelease) |
600 mg qd ×
14 days |
13 |
↓ 34
(↓ 21 to ↓ 47) |
↓ 55
(↓ 48 to ↓ 62) |
NA |
Hydroxybupropion |
|
|
|
↑ 50
(↑ 20 to ↑ 80) |
↔ |
NA |
Sertraline |
50 mg qd × 14
days |
600 mg qd ×
14 days |
13 |
↓ 29
(↓ 15 to ↓ 40) |
↓ 39
(↓ 27 to ↓ 50) |
↓ 46
(↓ 31 to ↓ 58) |
Voriconazole |
400 mg po q12h ×
1 day then 200 mg
po q12h x 8 days |
400 mg qd ×
9 days |
NA |
↓ 61i |
↓ 77i |
NA |
300 mg po q12h
days 2−7 |
300 mg qd ×
7 days |
NA |
↓ 36j
(↓ 21 to ↓ 49) |
↓ 55j
(↓ 45 to ↓ 62) |
NA |
400 mg po q12h
days 2−7 |
300 mg qd ×
7 days |
NA |
↑ 23j
(↓ 1 to ↑ 53) |
↓ 7j
(↓ 23 to ↑ 13) |
`NA |
NA = not available
a Increase = ↑; Decrease = ↓; No Effect = ↔
b Compared with atazanavir 400 mg qd alone.
c Comparator dose of indinavir was 800 mg q8h × 10 days.
d Parallel-group design; N for EFV + lopinavir/ritonavir, N for lopinavir/ritonavir alone.
e Values are for lopinavir. The pharmacokinetics of ritonavir 100 mg q12h are unaffected by concurrent EFV.
f 95% CI
g Soft Gelatin Capsule
h Not available because of insufficient data.
i 90% CI not available.
j Relative to steady-state administration of voriconazole (400 mg for 1 day, then 200 mg po q12h for 2 days).
k Study conducted with ATRIPLA coadministered with HARVONI.
l The predominant circulating nucleoside metabolite of sofosbuvir.
m Study conducted with ATRIPLA coadministered with SOVALDI® (sofosbuvir).
n Study conducted with ATRIPLA coadministered with EPCLUSA. |
Emtricitabine and Tenofovir DF
The steady-state pharmacokinetics of FTC and
tenofovir were unaffected when FTC and TDF were administered together versus each
agent dosed alone.
In vitro and clinical pharmacokinetic drug-drug interaction studies have shown that the
potential for CYP mediated interactions involving FTC and tenofovir with other medicinal
products is low.
TDF is a substrate of P-glycoprotein (P-gp) and breast cancer resistance protein
(BCRP) transporters. When TDF is coadministered with an inhibitor of these
transporters, an increase in absorption may be observed.
No clinically significant drug interactions have been observed between FTC and
famciclovir, indinavir, sofosbuvir/velpatasvir, stavudine, TDF, and zidovudine. Similarly,
no clinically significant drug interactions have been observed between TDF and
abacavir, EFV, FTC, entecavir, indinavir, lamivudine, lopinavir/ritonavir, methadone,
nelfinavir, oral contraceptives, ribavirin, saquinavir/ritonavir, sofosbuvir, or tacrolimus in
trials conducted in healthy volunteers.
Following multiple dosing to HIV-negative subjects receiving either chronic methadone
maintenance therapy, oral contraceptives, or single doses of ribavirin, steady-state
tenofovir pharmacokinetics were similar to those observed in previous trials, indicating a
lack of clinically significant drug interactions between these agents and TDF.
The effects of coadministered drugs on the Cmax, AUC, and Cmin of tenofovir are shown
in Table 6. The effects of coadministration of TDF on Cmax, AUC, and Cmin of
coadministered drugs are shown in Table 7.
Table 6: Drug Interactions: Changes in Pharmacokinetic Parameters for Tenofovir
in the Presence of the Coadministered Druga,b
Coadministered
Drug |
Dose of
Coadministered
Drug (mg) |
N |
Mean % Change of Tenofovir Pharmacokinetic Parametersc
(90% CI) |
Cmax |
AUC |
Cmin |
Atazanavird |
400 once daily
× 14 days |
33 |
↑ 14
(↑ 8 to ↑ 20) |
↑ 24
(↑ 21 to ↑ 28) |
↑ 22
(↑ 15 to ↑ 30) |
Atazanavir/
ritonavird |
300/100 once daily |
12 |
↑ 34
(↑ 20 to ↑ 51) |
↑ 37
(↑ 30 to ↑ 45) |
↑ 29
(↑ 21 to ↑ 36) |
Darunavir/
ritonavire |
300/100 twice daily |
12 |
↑ 24
(↑ 8 to ↑ 42) |
↑ 22
(↑ 10 to ↑ 35) |
↑ 37
(↑ 19 to ↑ 57) |
Didanosinef |
250 or 400 once
daily × 7 days |
14 |
↔ |
↔ |
↔ |
Ledipasvir/
sofosbuvir |
90/400 once daily |
15 |
↑ 79
(↑ 56 to ↑ 104) |
↑ 98
(↑ 77 to ↑ 123) |
↑ 163
(↑ 132 to ↑ 197) |
Lopinavir/ ritonavir |
400/100 twice daily
× 14 days |
24 |
↔ |
↑ 32
(↑ 25 to ↑ 38) |
↑ 51
(↑ 37 to ↑ 66) |
Sofosbuvir |
400 once daily |
16 |
↑ 25
(↑ 8 to ↑ 45) |
↔ |
↔ |
Sofosbuvir/
velpatasvir |
400/100 once daily |
15 |
↑ 77
(↑ 53 to ↑ 104) |
↑ 81
(↑ 68 to ↑ 94) |
↑ 121
(↑ 100 to ↑ 143) |
Tipranavir/
ritonavirg |
500/100 twice daily |
22 |
↓ 23
(↓ 32 to ↓ 13) |
↓ 2
(↓ 9 to ↑ 5) |
↑ 7
(↓ 2 to ↑ 17) |
750/200 twice daily
(23 doses) |
20 |
↓ 38
(↓ 46 to ↓ 29) |
↑ 2
(↓ 6 to ↑ 10) |
↑ 14
(↑ 1 to ↑ 27) |
a All interaction trials conducted in healthy volunteers.
b Subjects received TDF 300 mg once daily.
c Increase = ↑; Decrease = ↓; No Effect = ↔
d Reyataz Prescribing Information.
e Prezista Prescribing Information.
f Subjects received didanosine buffered tablets.
g Aptivus Prescribing Information. |
Table 7: Drug Interactions: Changes in Pharmacokinetic Parameters for
Coadministered Drug in the Presence of TDFa,b
Coadministered
Drug |
Dose of
Coadministered Drug
(mg) |
N |
Mean % Change of Coadministered Drug Pharmacokinetic
Parametersc
(90% CI) |
Cmax |
AUC |
Cmin |
Atazanavird |
400 once daily
× 14 days |
34 |
↓ 21
(↓ 27 to ↓ 14) |
↓ 25
(↓ 30 to ↓ 19) |
↓ 40
(↓ 48 to ↓ 32) |
Atazanavir/ritonavir
300/100 once daily
× 42 days |
10 |
↓ 28
(↓ 50 to ↑ 5) |
↓ 25e
(↓ 42 to ↓ 3) |
↓ 23e
(↓ 46 to ↑ 10) |
Darunavirf |
Darunavir/ritonavir
300/100 once daily |
12 |
↑ 16
(↓ 6 to ↑ 42) |
↑ 21
(↓ 5 to ↑ 54) |
↑ 24
(↓ 10 to ↑ 69) |
Didanosineg |
250 once,
simultaneously with
TDF and a light mealh |
33 |
↓ 20i
(↓ 32 to ↓ 7) |
↔i |
NA |
Lopinavir |
Lopinavir/ritonavir
400/100 twice daily ×
14 days |
24 |
↔ |
↔ |
↔ |
Ritonavir |
Lopinavir/ritonavir
400/100 twice daily ×
14 days |
24 |
↔ |
↔ |
↔ |
Tipranavirj |
Tipranavir/ritonavir
500/100 twice daily |
22 |
↓ 17
(↓ 26 to ↓ 6) |
↓ 18
(↓ 25 to ↓ 9) |
↓ 21
(↓ 30 to ↓ 10) |
Tipranavir/ritonavir
750/200 twice daily (23
doses) |
20 |
↓ 11
(↓ 16 to ↓ 4) |
↓ 9
(↓ 15 to ↓ 3) |
↓ 12
(↓ 22 to 0) |
a All interaction trials conducted in healthy volunteers.
b Subjects received TDF 300 mg once daily.
c Increase = ↑; Decrease = ↓; No Effect = ↔
d Reyataz Prescribing Information.
e In HIV-infected patients, addition of TDF to atazanavir 300 mg plus ritonavir 100 mg, resulted in AUC and Cmin
values of atazanavir that were 2.3- and 4-fold higher than the respective values observed for atazanavir 400 mg
when given alone.
f Prezista Prescribing Information.
g Videx EC Prescribing Information. Subjects received didanosine enteric-coated capsules.
h 373 kcal, 8.2 g fat.
i Compared with didanosine (enteric-coated) 400 mg administered alone under fasting conditions.
j Aptivus Prescribing Information. |
Microbiology
Mechanism Of Action
Efavirenz
EFV is a non-nucleoside reverse transcriptase (RT) inhibitor of HIV-1.
Efavirenz activity is mediated predominantly by noncompetitive inhibition of HIV-1
reverse transcriptase. HIV-2 RT and human cellular DNA polymerases α, β, γ, and δ are
not inhibited by EFV.
Emtricitabine
Emtricitabine, a synthetic nucleoside analog of cytidine, is
phosphorylated by cellular enzymes to form FTC 5'-triphosphate. Emtricitabine
5'-triphosphate inhibits the activity of the HIV-1 RT 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 γ
Tenofovir DF
TDF is an acyclic nucleoside phosphonate diester analog of adenosine
monophosphate. TDF requires initial diester hydrolysis for conversion to tenofovir and
subsequent phosphorylations by cellular enzymes to form tenofovir diphosphate.
Tenofovir diphosphate inhibits the activity of HIV-1 RT by competing with the natural
substrate deoxyadenosine 5′-triphosphate and, after incorporation into DNA, by DNA
chain termination. Tenofovir diphosphate is a weak inhibitor of mammalian DNA
polymerases α, β, and mitochondrial DNA polymerase γ.
Antiviral Activity
Efavirenz, Emtricitabine, and Tenofovir DF
In combination studies evaluating the
antiviral activity in cell culture of FTC and EFV together, EFV and tenofovir together,
and FTC and tenofovir together, additive to synergistic antiviral effects were observed.
Efavirenz
The concentration of EFV inhibiting replication of wild-type laboratory
adapted strains and clinical isolates in cell culture by 90–95% (EC90-95) ranged from
1.7−25 nM in lymphoblastoid cell lines, peripheral blood mononuclear cells, and
macrophage/monocyte cultures. Efavirenz demonstrated additive antiviral activity
against HIV-1 in cell culture when combined with non-nucleoside reverse transcriptase
inhibitors (NNRTIs) (delavirdine and nevirapine), nucleoside reverse transcriptase
inhibitors (NRTIs) (abacavir, didanosine, lamivudine, stavudine, zalcitabine, and
zidovudine), protease inhibitors (PIs) (amprenavir, indinavir, lopinavir, nelfinavir,
ritonavir, and saquinavir), and the fusion inhibitor enfuvirtide. Efavirenz demonstrated
additive to antagonistic antiviral activity in cell culture with atazanavir. Efavirenz
demonstrated antiviral activity against clade B and most non-clade B isolates (subtypes
A, AE, AG, C, D, F, G, J, and N), but had reduced antiviral activity against group O
viruses. Efavirenz is not active against HIV-2.
Emtricitabine
The antiviral activity in cell culture of FTC against laboratory and clinical
isolates of HIV-1 was assessed in lymphoblastoid cell lines, the MAGI-CCR5 cell line,
and peripheral blood mononuclear cells. The 50% effective concentration (EC50) values
for FTC were in the range of 0.0013–0.64 μM (0.0003–0.158 μg/mL). In drug
combination studies of FTC with NRTIs (abacavir, lamivudine, stavudine, zalcitabine,
and zidovudine), NNRTIs (delavirdine, EFV, and nevirapine), and PIs (amprenavir,
nelfinavir, ritonavir, and saquinavir), additive to synergistic effects were observed.
Emtricitabine displayed antiviral activity in cell culture against HIV-1 clades A, B, C, D,
E, F, and G (EC50 values ranged from 0.007–0.075 μM) and showed strain-specific
activity against HIV-2 (EC50 values ranged from 0.007–1.5 μM).
Tenofovir DF
The antiviral activity in cell culture of tenofovir against laboratory and
clinical isolates of HIV-1 was assessed in lymphoblastoid cell lines, primary
monocyte/macrophage cells and peripheral blood lymphocytes. The EC50 values for
tenofovir were in the range of 0.04–8.5 μM. In drug combination studies of tenofovir with
NRTIs (abacavir, didanosine, lamivudine, stavudine, zalcitabine, and zidovudine),
NNRTIs (delavirdine, EFV, and nevirapine), and PIs (amprenavir, indinavir, nelfinavir,
ritonavir, and saquinavir), additive to synergistic effects were observed. Tenofovir
displayed antiviral activity in cell culture against HIV-1 clades A, B, C, D, E, F, G, and O
(EC50 values ranged from 0.5–2.2 μM) and showed strain-specific activity against HIV-2
(EC50 values ranged from 1.6–5.5 μM).
Resistance
EFV, FTC, and TDF
HIV-1 isolates with reduced susceptibility to the combination of
FTC and tenofovir have been selected in cell culture and in clinical trials. Genotypic
analysis of these isolates identified the M184V/I and/or K65R amino acid substitutions in
the viral RT. In addition, a K70E substitution in HIV-1 reverse transcriptase has been
selected by tenofovir and results in reduced susceptibility to tenofovir.
In a clinical trial of treatment-naïve subjects [Study 934, see Clinical Studies]
resistance analysis was performed on HIV-1 isolates from all confirmed virologic failure
subjects with greater than 400 copies/mL of HIV-1 RNA at Week 144 or early
discontinuations. Genotypic resistance to EFV, predominantly the K103N substitution,
was the most common form of resistance that developed. Resistance to EFV occurred
in 13/19 analyzed subjects in the FTC + TDF group and in 21/29 analyzed subjects in
the zidovudine/lamivudine fixed-dose combination group. The M184V amino acid
substitution, associated with resistance to FTC and lamivudine, was observed in 2/19
analyzed subject isolates in the FTC + TDF group and in 10/29 analyzed subject
isolates in the zidovudine/lamivudine group. Through 144 weeks of Study 934, no
subjects developed a detectable K65R substitution in their HIV-1 as analyzed through
standard genotypic analysis.
In a clinical trial of treatment-naïve subjects, isolates from 8/47 (17%) analyzed subjects
receiving TDF developed the K65R substitution through 144 weeks of therapy; 7 of
these occurred in the first 48 weeks of treatment and one at Week 96. In treatment
experienced subjects, 14/304 (5%) of TDF treated subjects with virologic failure through
Week 96 showed greater than 1.4-fold (median 2.7) reduced susceptibility to tenofovir.
Genotypic analysis of the resistant isolates showed a substitution in the HIV-1 RT gene
resulting in the K65R amino acid substitution.
Efavirenz
Clinical isolates with reduced susceptibility in cell culture to EFV have been
obtained. The most frequently observed amino acid substitution in clinical trials with
EFV is K103N (54%). One or more RT substitutions at amino acid positions 98, 100,
101, 103, 106, 108, 188, 190, 225, 227, and 230 were observed in subjects failing
treatment with EFV in combination with other antiretrovirals. Other resistance
substitutions observed to emerge commonly included L100I (7%), K101E/Q/R (14%),
V108I (11%), G190S/T/A (7%), P225H (18%), and M230I/L (11%).
HIV-1 isolates with reduced susceptibility to EFV (greater than 380-fold increase in EC90
value) emerged rapidly under selection in cell culture. Genotypic characterization of
these viruses identified substitutions resulting in single amino acid substitutions L100I or
V179D, double substitutions L100I/V108I, and triple substitutions L100I/V179D/Y181C
in RT.
Emtricitabine
Emtricitabine-resistant isolates of HIV-1 have been selected in cell
culture and in clinical trials. Genotypic analysis of these isolates showed that the
reduced susceptibility to FTC was associated with a substitution in the HIV-1 RT gene
at codon 184 which resulted in an amino acid substitution of methionine by valine or
isoleucine (M184V/I).
Tenofovir DF
HIV-1 isolates with reduced susceptibility to tenofovir have been selected
in cell culture. These viruses expressed a K65R substitution in RT and showed a 2- to
4-fold reduction in susceptibility to tenofovir.
Cross Resistance
Efavirenz, Emtricitabine, and Tenofovir DF
Cross resistance has been recognized
among NNRTIs. Cross resistance has also been recognized among certain NRTIs. The
M184V/I and/or K65R substitutions selected in cell culture by the combination of FTC
and tenofovir are also observed in some HIV-1 isolates from subjects failing treatment
with tenofovir in combination with either lamivudine or FTC, and either abacavir or
didanosine. Therefore, cross resistance among these drugs may occur in patients
whose virus harbors either or both of these amino acid substitutions.
Efavirenz
Clinical isolates previously characterized as EFV resistant were also
phenotypically resistant in cell culture to delavirdine and nevirapine compared to
baseline. Delavirdine- and/or nevirapine-resistant clinical viral isolates with NNRTI
resistance-associated substitutions (A98G, L100I, K101E/P, K103N/S, V106A, Y181X,
Y188X, G190X, P225H, F227L, or M230L) showed reduced susceptibility to EFV in cell
culture. Greater than 90% of NRTI-resistant isolates tested in cell culture retained
susceptibility to EFV.
Emtricitabine
Emtricitabine-resistant isolates (M184V/I) were cross resistant to
lamivudine but retained susceptibility in cell culture to didanosine, stavudine, tenofovir,
zidovudine, and NNRTIs (delavirdine, EFV, and nevirapine). HIV-1 isolates containing
the K65R substitution, selected in vivo by abacavir, didanosine, and tenofovir,
demonstrated reduced susceptibility to inhibition by FTC. Viruses harboring
substitutions conferring reduced susceptibility to stavudine and zidovudine (M41L,
D67N, K70R, L210W, T215Y/F, and K219Q/E) or didanosine (L74V) remained sensitive
to FTC.
Tenofovir DF
Cross resistance has been observed among NRTIs. The K65R
substitution in HIV-1 RT selected by tenofovir is also selected in some HIV-1 infected
patients treated with abacavir, or didanosine. HIV-1 isolates with the K65R substitution
also showed reduced susceptibility to FTC and lamivudine. Therefore, cross resistance
among these drugs may occur in patients whose virus harbors the K65R substitution.
The K70E substitution selected clinically by TDF results in reduced susceptibility to
abacavir, didanosine, FTC, and lamivudine. HIV-1 isolates from subjects (N=20) whose
HIV-1 expressed a mean of 3 zidovudine-associated RT amino acid substitutions
(M41L, D67N, K70R, L210W, T215Y/F, or K219Q/E/N) showed a 3.1-fold decrease in
the susceptibility to tenofovir. Subjects whose virus expressed an L74V substitution
without zidovudine resistance associated substitutions (N=8) had reduced response to
TDF. Limited data are available for patients whose virus expressed a Y115F substitution
(N=3), Q151M substitution (N=2), or T69 insertion (N=4), all of whom had a reduced
response.
Animal Toxicology And/Or Pharmacology
Efavirenz
Nonsustained convulsions were observed in 6 of 20 monkeys receiving EFV
at doses yielding plasma AUC values 4- to 13-fold greater than those in humans given
the recommended dose.
Tenofovir DF
Tenofovir and TDF administered in toxicology studies to rats, dogs, and
monkeys at exposures (based on AUCs) greater than or equal to 6-fold those observed
in humans caused bone toxicity. In monkeys the bone toxicity was diagnosed as
osteomalacia. Osteomalacia observed in monkeys appeared to be reversible upon dose
reduction or discontinuation of tenofovir. In rats and dogs, the bone toxicity manifested
as reduced bone mineral density. The mechanism(s) underlying bone toxicity is
unknown.
Evidence of renal toxicity was noted in 4 animal species administered tenofovir and
TDF. Increases in serum creatinine, BUN, glycosuria, proteinuria, phosphaturia and/or
calciuria and decreases in serum phosphate were observed to varying degrees in these
animals. These toxicities were noted at exposures (based on AUCs) 2- to 20-times
higher than those observed in humans. The relationship of the renal abnormalities,
particularly the phosphaturia, to the bone toxicity is not known.
Clinical Studies
Clinical Study 934 (NCT00112047) supports the use of ATRIPLA tablets in antiretroviral
treatment-naïve HIV-1 infected patients.
Clinical Study 073 (NCT00365612) provides clinical experience in subjects with stable,
virologic suppression and no history of virologic failure who switched from their current
regimen to ATRIPLA.
In antiretroviral treatment-experienced patients, the use of ATRIPLA tablets may be
considered for patients with HIV-1 strains that are expected to be susceptible to the
components of ATRIPLA as assessed by treatment history or by genotypic or
phenotypic testing [see Microbiology].
Study 934
Data through 144 weeks are reported for Study 934, a randomized, openlabel,
active-controlled multicenter trial comparing FTC + TDF administered in
combination with EFV versus zidovudine/lamivudine fixed-dose combination
administered in combination with EFV in 511 antiretroviral-naïve subjects. From Weeks
96 to 144 of the trial, subjects received FTC/TDF fixed-dose combination with EFV in
place of FTC + TDF with EFV. Subjects had a mean age of 38 years (range 18–80);
86% were male, 59% were Caucasian, and 23% were Black. The mean baseline CD4+
cell count was 245 cells/mm3 (range 2–1191), and median baseline plasma HIV-1 RNA
was 5.01 log10 copies/mL (range 3.56–6.54). Subjects were stratified by baseline CD4+
cell count (< or ≥200 cells/mm3), and 41% had CD4+ cell counts <200 cells/mm3. Fiftyone
percent (51%) of subjects had baseline viral loads >100,000 copies/mL. Treatment
outcomes through 48 and 144 weeks for those subjects who did not have EFV
resistance at baseline (N=487) are presented in Table 8.
Table 8: Virologic Outcomes of Randomized Treatment at Weeks 48 and 144 (Study
934)
Outcomes |
At Week 48 |
At Week 144 |
FTC+TDF
+EFV
(N=244) |
AZT/3TC
+EFV
(N=243) |
FTC+TDF
+EFV
(N=227)a |
AZT/3TC
+EFV
(N=229)a |
Responderb |
84% |
73% |
71% |
58% |
Virologic failurec |
2% |
4% |
3% |
6% |
Rebound |
1% |
3% |
2% |
5% |
Never suppressed |
0% |
0% |
0% |
0% |
Change in antiretroviral
regimen |
1% |
1% |
1% |
1% |
Death |
<1% |
1% |
1% |
1% |
Discontinued due to adverse
event |
4% |
9% |
5% |
12% |
Discontinued for other
reasonsd |
10% |
14% |
20% |
22% |
a Subjects who were responders at Week 48 or Week 96 (HIV-1 RNA <400 copies/mL) but did not consent to
continue trial after Week 48 or Week 96 were excluded from analysis.
b Subjects achieved and maintained confirmed HIV-1 RNA <400 copies/mL through Weeks 48 and 144.
c Includes confirmed viral rebound and failure to achieve confirmed HIV-1 RNA <400 copies/mL through Weeks 48
and 144.
d Includes lost to follow-up, patient withdrawal, noncompliance, protocol violation and other reasons. |
Through Week 48, 84% and 73% of subjects in the FTC + TDF group and the
zidovudine/lamivudine group, respectively, achieved and maintained HIV-1 RNA
<400 copies/mL (71% and 58% through Week 144). The difference in the proportion of
subjects who achieved and maintained HIV-1 RNA <400 copies/mL through 48 weeks
largely results from the higher number of discontinuations due to adverse events and
other reasons in the zidovudine/lamivudine group in this open-label trial. In addition,
80% and 70% of subjects in the FTC + TDF group and the zidovudine/lamivudine group,
respectively, achieved and maintained HIV-1 RNA <50 copies/mL through Week 48
(64% and 56% through Week 144). The mean increase from baseline in CD4+ cell
count was 190 cells/mm3 in the FTC + TDF group and 158 cells/mm3 in the
zidovudine/lamivudine group at Week 48 (312 and 271 cells/mm3 at Week 144).
Through 48 weeks, 7 subjects in the FTC + TDF group and 5 subjects in the
zidovudine/lamivudine group experienced a new CDC Class C event (10 and 6 subjects
through 144 weeks).
Study 073
Study 073 was a 48-week open-label, randomized clinical trial in subjects
with stable virologic suppression on combination antiretroviral therapy consisting of at
least two NRTIs administered in combination with a protease inhibitor (with or without
ritonavir) or a NNRTI.
To be enrolled, subjects were to have HIV-1 RNA <200 copies/mL for at least 12 weeks
on their current regimen prior to trial entry with no known HIV-1 substitutions conferring
resistance to the components of ATRIPLA and no history of virologic failure.
The trial compared the efficacy of switching to ATRIPLA or staying on the baseline
antiretroviral regimen (SBR). Subjects were randomized in a 2:1 ratio to switch to
ATRIPLA (N=203) or stay on SBR (N=97). Subjects had a mean age of 43 years (range
22-73 years); 88% were male, 68% were white, 29% were Black or African-American,
and 3% were of other races. At baseline, median CD4+ cell count was 516 cells/mm3,
and 96% had HIV-1 RNA <50 copies/mL. The median time since onset of antiretroviral
therapy was 3 years, and 88% of subjects were receiving their first antiretroviral
regimen at trial enrollment.
At Week 48, 89% and 87% of subjects who switched to ATRIPLA maintained HIV RNA
<200 copies/mL and <50 copies/mL, respectively, compared to 88% and 85% who
remained on SBR; this difference was not statistically significant. No changes in CD4+
cell counts from baseline to Week 48 were observed in either treatment arm.