Lamivudine:After oral administration of 2 mg/kg of 3TC twice a day to 9 adults with HIV-1, the peak serum 3TC concentration (C
max) was 1.5
±0.5 mcg/mL (mean
±SD). The area under the plasma concentration versus time curve (AUC) and C
maxincreased in proportion to oral dose over the range from 0.25 to 10 mg/kg and absolute bioavailability in 12 adult patients was 86% ± 16% (mean ± SD) for the 150-mg tablet and 87% ± 13% for the oral solution. Binding of 3TC to human plasma proteins is low (< 36%). Within 12 hours after a single oral dose of 3TC in 6 HIV-1-infected adults, 5.2% ± 1.4% (mean ± SD) of the dose was excreted as the trans-sulfoxide metabolite in the urine. The majority of 3TC is eliminated unchanged in urine by active organic cationic secretion and the observed mean elimination half-life (t
1/2) ranged from 5 to 7 hours in most single-dose studies with serum sampling for 24 hours after dosing.
Tenofovir disoproxil fumarate:Following oral administration of a single 300 mg dose of TDF to HIV-1 infected subjects in the fasted state, maximum serum concentrations (C
max) were achieved in 1.0
±0.4 hrs (mean ± SD) and C
maxand 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
vitroand the binding is independent of concentration over the range of 0.01 to 25 mcg/mL. Approximately 70 to 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.
Specific Populations
Geriatric Patients:The pharmacokinetics of lamivudine and tenofovir disoproxil fumarate have not been studied in patients over 65 years of age.
Gender:There are no significant or clinically relevant gender differences in the pharmacokinetics of lamivudine and tenofovir.
Race
Lamivudine:There are no significant or clinically relevant racial differences in 3TC pharmacokinetics.
Tenofovir Disoproxil Fumarate:There were insufficient numbers from racial and ethnic groups other than Caucasian to adequately determine potential pharmacokinetic differences among these populations.
Patients with Renal Impairment: [see
Use in Specific Populations (8.6)].
Lamivudine:The pharmacokinetic of lamivudine are altered in subjects with impaired renal function (Table 4).
Table 4: Pharmacokinetic Parameters (Mean ± SD) after a Single 300-mg Oral Dose of 3TC in Subjects with Varying Degrees of Renal Function| Parameter | Creatinine Clearance Criterion (Number of Subjects) |
|---|
>60 mL/min
(n = 6)
| 10-30 mL/min
(n = 4)
| <10 mL/min
(n = 6)
|
|---|
| Creatinine clearance (mL/min) | 111 ± 14 | 28 ± 8 | 6 ± 2 |
| C
max(mcg/mL)
| 2.6 ± 0.5 | 3.6 ± 0.8 | 5.8 ± 1.2 |
| AUC
∞(mcg•hr/mL)
| 11.0 ± 1.7 | 48.0 ± 19 | 157 ± 74 |
| Cl/F (mL/min) | 464 ± 76 | 114 ± 34 | 36 ± 11 |
Tenofovir Disoproxil Fumarate:The pharmacokinetics of tenofovir are altered in subjects with renal impairment
[see
Warnings and Precautions (5.2)]
. In subjects with creatinine clearance below 50 mL/min or with end-stage renal disease (ESRD) requiring dialysis, C
max, and AUC
0-∞ of tenofovir were increased (Table 5).
Table 5: Pharmacokinetic Parameters (Mean ± SD) of Tenofovir in Subjects after a Single 300 mg Oral Dose of TDF in Subjects with Varying Degrees of Renal FunctionBaseline Creatinine Clearance
(mL/min)
| >80 (N=3) | 50-80 (N=10) | 30-49 (N=8) | 12-29 (N=11) |
|---|
|
| C
max(mcg/mL)
| 0.34 ± 0.03 | 0.33 ± 0.06 | 0.37 ± 0.16 | 0.60 ± 0.19 |
| AUC
0-∞(mcg•hr/mL)
| 2.18 ± 0.26 | 3.06 ± 0.93 | 6.01 ± 2.50 | 15.98 ± 7.22 |
| CL/F (mL/min) | 1043.7 ± 115.4 | 807.7 ± 279.2 | 444.4 ± 209.8 | 177.0 ± 97.1 |
| CL
renal(mL/min)
| 243.5 ± 33.3 | 168.6 ± 27.5 | 100.6 ± 27.5 | 43.0 ± 31.2 |
Patients with Hepatic Impairment
Lamivudine: The pharmacokinetics of lamivudine were not altered by diminishing hepatic function. Safety and efficacy of lamivudine have not been established in the presence of decompensated liver disease.
Tenofovir Disoproxil Fumarate: The pharmacokinetics of tenofovir following a 300 mg single dose of TDF have been studied in non-HIV infected subjects with moderate to severe (Child-Pugh B to C) hepatic impairment. There were no substantial alterations in tenofovir pharmacokinetics in subjects with hepatic impairment compared with unimpaired subjects.
Assessment of Drug Interactions
:
[see
Drug Interactions (7)]
Lamivudine
Effect of Lamivudine on the Pharmacokinetics of Other Agents:Based on
in vitrostudy results, 3TC at therapeutic drug exposures is not expected to affect the pharmacokinetics of drugs that are substrates of the following transporters: organic anion transporter polypeptide 1B1/3 (OATP1B1/3), breast cancer resistance protein (BCRP), P-glycoprotein (P-gp), multidrug and toxin extrusion protein 1 (MATE1), MATE2-K, organic cation transporter 1 (OCT1), OCT2, or OCT3.
Effect of Other Agents on the Pharmacokinetics of 3TC:3TC is a substrate of MATE1, MATE2-K, and OCT2
in vitro. Trimethoprim (an inhibitor of these drug transporters) has been shown to increase 3TC plasma concentrations. This interaction is not considered clinically significant as no dose adjustment of 3TC is needed.
3TC is a substrate of P-gp and BCRP; however, considering its absolute bioavailability (87%), it is unlikely that these transporters play a significant role in the absorption of 3TC. Therefore, coadministration of drugs that are inhibitors of these efflux transporters is unlikely to affect the disposition and elimination of 3TC.
Interferon Alfa:There was no significant pharmacokinetic interaction between 3TC and interferon alfa in a trial of 19 healthy male subjects
[see
Warnings and Precautions (5.7)].
Ribavirin: In vitrodata indicate ribavirin reduces phosphorylation of 3TC, stavudine, and zidovudine. However, no pharmacokinetic (e.g., plasma concentrations or intracellular triphosphorylated active metabolite concentrations) or pharmacodynamic (e.g., loss of HIV-1/HCV virologic suppression) interaction was observed when ribavirin and 3TC (n = 18), stavudine (n = 10), or zidovudine (n = 6) were coadministered as part of a multi-drug regimen to HIV-1/HCV co-infected subjects
[see
Warnings and Precautions (5.7)].
Sorbitol (Excipient):3TC and sorbitol solutions were coadministered to 16 healthy adult subjects in an open-label, randomized-sequence, 4-period, crossover trial. Each subject received a single 300-mg dose of 3TC oral solution alone or coadministered with a single dose of 3.2 grams, 10.2 grams, or 13.4 grams of sorbitol in solution. Coadministration of 3TC with sorbitol resulted in dose-dependent decreases of 20%, 39%, and 44% in the AUC
(0-24), 14%, 32%, and 36% in the AUC
(∞), and 28%, 52%, and 55% in the C
maxof 3TC, respectively.
Trimethoprim/Sulfamethoxazole:3TC and TMP/SMX were coadministered to 14 HIV-1-positive subjects in a single-center, open-label, randomized, crossover trial. Each subject received treatment with a single 300-mg dose of 3TC and TMP 160 mg/SMX 800 mg once a day for 5 days with concomitant administration of 3TC 300 mg with the fifth dose in a crossover design. Coadministration of TMP/SMX with 3TC resulted in an increase of 43% ± 23% (mean ± SD) in lamivudine AUC
∞, a decrease of 29% ±13% in lamivudine oral clearance, and a decrease of 30% ± 36% in 3TC renal clearance. The pharmacokinetic properties of TMP and SMX were not altered by coadministration with 3TC. There is no information regarding the effect on 3TC pharmacokinetics of higher doses of TMP/SMX such as those used in treat PCP.
Tenofovir Disoproxil Fumarate: At concentrations substantially higher (~300-fold) than those observed
in vivo, tenofovir did not inhibit
in vitroCYP3A4, CYP2D6, CYP2C9, or CYP2E1. However, a small (6%) but statistically significant reduction in metabolism of CYP1A substrate was observed. Based on the results of
in vitroexperiments and the known elimination pathway of tenofovir, the potential for CYP-mediated interactions involving tenofovir with other medicinal products is low.
TDF has been evaluated in healthy volunteers in combination with other antiretroviral and potential concomitant drugs. Tables 6 and 7 summarize pharmacokinetic effects of coadministered drug on tenofovir pharmacokinetics and effects of TDF on the pharmacokinetics of coadministered drug.
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 TDF and efavirenz, methadone, nelfinavir, oral contraceptives, ribavirin, or sofosbuvir.
Table 6: Drug Interactions: Changes in Pharmacokinetic Parameters for Tenofovir
ain the Presence of the Coadministered Drug
| % Change of Tenofovir Pharmacokinetic Parameters
b(90% CI)
|
|---|
| Coadministered Drug | Dose of Coadministered Drug
(mg)
| N | C
max
| AUC | C
min
|
|---|
aSubjects received VIREAD
®300 mg once daily.
bIncrease = ↑; Decrease = ↓; No Effect = ↔
cReyataz
® (atazanavir) Prescribing Information.
dPrezista
® (darunavir) Prescribing Information.
eData generated from simultaneous dosing with HARVONI
®(ledipasvir/sofosbuvir). Staggered administration (12 hours apart) provided similar results.
f Comparison based on exposures when administered as atazanavir/ritonavir + FTC/TDF.
g Comparison based on exposures when administered as darunavir/ritonavir + FTC/TDF.
hStudy conducted with ATRIPLA
®(EFV/FTC/TDF) coadministered with HARVONI
®; coadministration with HARVONI
®also results in comparable increases in tenofovir exposure when tenofovir DF is administered as COMPLERA
®(FTC/rilpivirine/TDF), or TRUVADA
®+ dolutegravir.
i Study conducted with ATRIPLA
®coadministered with SOVALDI
®(sofosbuvir).
j Study conducted with COMPLERA
®coadministered with EPCLUSA
®; coadministration with EPCLUSA
®also results in comparable increases in tenofovir exposures when TDF is administered as ATRIPLA
®, STRIBILD
®(elvitegravir/cobicistat/FTC/TDF), TRUVADA
®+ atazanavir/ritonavir, or TRUVADA
®+ darunavir/ritonavir.
k Administered as raltegravir + FTC/TDF.
l Comparison based on exposures when administered as darunavir/ritonavir + FTC/TDF.
mStudy conducted with additional voxilaprevir 100 mg to achieve voxilaprevir exposures expected in HCV-infected patients.
n Aptivus
®(tipranavir) Prescribing Information.
|
| Atazanavir
c
| 400 once daily × 14 days | 33 | ↑14
(↑8 to ↑20)
| ↑24
(↑21 to ↑28)
| ↑22
(↑15 to ↑30)
|
| Atazanavir/ Ritonavir
c
| 300/100 once daily | 12 | ↑34
(↑20 to ↑51)
| ↑37
(↑30 to ↑45)
| ↑29
(↑21 to ↑36)
|
| Darunavir/ Ritonavir
d
| 300/100 twice daily | 12 | ↑24
(↑8 to ↑42)
| ↑22
(↑10 to ↑35)
| ↑37
(↑19 to ↑57)
|
| Indinavir | 800 three times daily × 7 days | 13 | ↑14
(↓3 to ↑33)
| ↔ | ↔ |
| Ledipasvir/ Sofosbuvir
e,f
| 90/400 once daily × 10 days | 24 | ↑47
(↑37 to ↑58)
| ↑35
(↑29 to ↑42)
| ↑47
(↑38 to ↑57)
|
| Ledipasvir/ Sofosbuvir
e,g
| 23 | ↑64
(↑54 to ↑74)
| ↑50
(↑42 to ↑59)
| ↑59
(↑49 to ↑70)
|
| Ledipasvir/ Sofosbuvir
h
| 90/400 once daily × 14 days | 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)
|
| Saquinavir/ Ritonavir | 1000/100 twice daily × 14 days | 35 | ↔ | ↔ | ↑23
(↑16 to ↑30)
|
| Sofosbuvir
i
| 400 single dose | 16 | ↑25
(↑8 to ↑45)
| ↔ | ↔ |
| Sofosbuvir/ Velpatasvir
j
| 400/100 once daily | 24 | ↑44
(↑33 to ↑55)
| ↑40
(↑34 to ↑46)
| ↑84
(↑76 to ↑92)
|
| Sofosbuvir/ Velpatasvir
k
| 400/100 once daily | 30 | ↑46
(↑39 to ↑54)
| ↑40
(↑34 to ↑45)
| ↑70
(↑61 to ↑79)
|
Sofosbuvir/ Velpatasvir/
Voxilaprevir
l
| 400/100/100 + Voxilaprevir
m100 once daily
| 29 | ↑48
(↑36 to ↑61)
| ↑39
(↑32 to ↑46)
| ↑47
(↑38 to ↑56)
|
| Tacrolimus | 0.05 mg/kg twice daily × 7 days | 21 | ↑13
(↑1 to ↑27)
| ↔ | ↔ |
| Tipranavir/ Ritonavir
n
| 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)
|
No effect on the pharmacokinetic parameters of the following coadministered drugs was observed with TDF: abacavir, didanosine (buffered tablets), emtricitabine, entecavir, and lamivudine.
Table 7: Drug Interactions: Changes in Pharmacokinetic Parameters for Coadministered Drug in the Presence of TDF | % Change of Coadministered Drug
Pharmacokinetic Parameters
a(90% CI)
|
|---|
| Coadministered Drug | Dose of Coadministered Drug
(mg)
| N | C
max
| AUC | C
min
|
|---|
aIncrease = ↑; Decrease = ↓; No Effect = ↔; NA = Not Applicable
bReyataz
® (atazanavir) Prescribing Information.
cIn HIV-infected subjects, addition of TDF to atazanavir 300 mg plus ritonavir 100 mg, resulted in AUC and C
minvalues of atazanavir that were 2.3- and 4-fold higher than the respective values observed for atazanavir 400 mg when given alone.
dPrezista
® (darunavir) Prescribing Information.
eVidex
®EC (didanosine) Prescribing Information. Subjects received didanosine enteric-coated capsules.
f373 kcal, 8.2 g fat
gCompared with didanosine (enteric-coated) 400 mg administered alone under fasting conditions.
hIncreases in AUC and C
minare not expected to be clinically relevant; hence no dose adjustments are required when TDF and ritonavir-boosted saquinavir are coadministered.
iAptivus
® (tipranavir) Prescribing Information.
|
| Abacavir | 300 once | 8 | ↑12
(↓1 to ↑26)
| ↔ | NA |
| Atazanavir
b
| 400 once daily × 14 days | 34 | ↓21
(↓27 to ↓14)
| ↓25
(↓30 to ↓19)
| ↓40
(↓48 to ↓32)
|
| Atazanavir
b
| Atazanavir/ Ritonavir 300/100
once daily × 42 days
| 10 | ↓28
(↓50 to ↑5)
| ↓25
c
(↓42 to ↓3)
| ↓23
c
(↓46 to ↑10)
|
| Darunavir
d
| Darunavir/Ritonavir 300/100 once daily | 12 | ↑16
(↓6 to ↑42)
| ↑21
(↓5 to ↑54)
| ↑24
(↓10 to ↑69)
|
| Didanosine
e
| 250 once, simultaneously with tenofovir and a light meal
f
| 33 | ↓20
g
(↓32 to ↓7)
| ↔
g
| NA |
| Emtricitabine | 200 once daily × 7 days | 17 | ↔ | ↔ | ↑20
(↑12 to ↑29)
|
| Entecavir | 1 mg once daily × 10 days | 28 | ↔ | ↑13
(↑11 to ↑15)
| ↔ |
| Indinavir | 800 three times daily × 7 days | 12 | ↓11
(↓30 to ↑12)
| ↔ | ↔ |
| Lamivudine | 150 twice daily × 7 days | 15 | ↓24
(↓34 to ↓12)
| ↔ | ↔ |
| Lopinavir | Lopinavir/Ritonavir 400/100 twice daily × 14 days | 24 | ↔ | ↔ | ↔ |
| Ritonavir | ↔ | ↔ | ↔ |
| Saquinavir | Saquinavir/Ritonavir 1000/100 twice daily × 14 days | 32 | ↑22
(↑6 to ↑41)
| ↑29
h
(↑12 to ↑48)
| ↑47
h
(↑23 to ↑76)
|
| Ritonavir | ↔ | ↔ | ↑23
(↑3 to ↑46)
|
| Tacrolimus | 0.05 mg/kg twice daily 7 days | 21 | ↔ | ↔ | ↔ |
| Tipranavir
i
| 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)
|