Clinical Pharmacology for Odefsey
Mechanism of Action
ODEFSEY is a fixed dose combination of antiretroviral drugs emtricitabine, rilpivirine, and tenofovir alafenamide [see Microbiology (12.4)].
Pharmacodynamics
Cardiac Electrophysiology
When higher than recommended RPV doses of 75 mg (3 times the recommended dosage in ODEFSEY) once daily and 300 mg (12 times the recommended dosage in ODEFSEY) once daily were studied in healthy adults, the maximum mean time-matched (95% upper confidence bound) differences in QTcF interval from placebo after baseline correction were 10.7 (15.3) and 23.3 (28.4) milliseconds, respectively. Steady-state administration of RPV 75 mg once daily and 300 mg once daily resulted in a mean steady-state Cmax approximately 2.6 times and 6.7 times, respectively, higher than the mean Cmax observed with the recommended 25 mg once daily dose of RPV [see Warnings and Precautions (5.6)].
The effect of RPV at the recommended dose of 25 mg once daily on the QTcF interval was evaluated in a randomized, placebo-, and active- (moxifloxacin 400 mg once daily) controlled crossover study in 60 healthy adults, with 13 measurements over 24 hours at steady state. The maximum mean time-matched (95% upper confidence bound) differences in QTcF interval from placebo after baseline correction was 2 (5) milliseconds (i.e., below the threshold of clinical concern).
In a thorough QT/QTc study in 48 healthy participants, TAF at the recommended dose and at a dose approximately 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.
Pharmacokinetics
Absorption, Distribution, Metabolism, and Excretion
The pharmacokinetic properties of the components of ODEFSEY are provided in Table 5. The multiple dose pharmacokinetic parameters of FTC, RPV and TAF and its metabolite tenofovir are provided in Table 6.
Table 5 Pharmacokinetic Properties of the Components of ODEFSEY
|
Rilpivirine
|
Emtricitabine
|
Tenofovir Alafenamide
|
|
Absorption
|
|
Tmax (h)
|
4
|
3
|
1
|
|
Effect of moderate fat meal (relative to fasting)a
|
AUC Ratio = 1.13
(1.03, 1.23)
|
AUC Ratio =0.91
(0.89, 0.93)
|
AUC Ratio = 1.45
(1.33, 1.58)
|
|
Effect of high fat meal (relative to fasting)a
|
AUC Ratio = 1.72 (1.49, 1.99)
|
AUC Ratio = 0.88
(0.85, 0.90)
|
AUC Ratio = 1.53
(1.39, 1.69)
|
|
Distribution
|
|
% Bound to human plasma proteins
|
~99
|
<4
|
~80
|
|
Source of protein binding data
|
In vitro
|
In vitro
|
Ex vivo
|
|
Blood-to-plasma ratio
|
0.7
|
0.6
|
1.0
|
|
Metabolism
|
|
Metabolism
|
CYP3A
|
Not significantly metabolized
|
Cathepsin Ab (PBMCs)
CES1 (hepatocytes)
CYP3A (minimal)
|
|
Elimination
|
|
Major route of elimination
|
Metabolism
|
Glomerular filtration and active tubular secretion
|
Metabolism (>80% of oral dose)
|
|
t1/2 (h)c
|
50
|
10
|
0.51
|
|
% Of dose excreted in urined
|
6
|
70
|
<1
|
|
% Of dose excreted in fecesd
|
85
|
13.7
|
31.7
|
|
PBMCs = peripheral blood mononuclear cells; CES1 = carboxylesterase 1.
- Values refer to geometric mean ratio [fed/ fasted] in PK parameters and (90% confidence interval). High-calorie/high-fat meal = ~800 kcal, 50% fat. Moderate-fat meal = ~600 kcal, 27% fat.
- In vivo, TAF is hydrolyzed within cells to form tenofovir (major metabolite), which is phosphorylated to the active metabolite, tenofovir In vitro studies have shown that TAF is metabolized to tenofovir by cathepsin A in PBMCs and macrophages; and by CES1 in hepatocytes. Upon coadministration with the moderate CYP3A inducer probe efavirenz, TAF exposure was unaffected.
- t1/2 values refer to median terminal plasma half-life. Note that the pharmacologically active metabolite, tenofovir diphosphate, has a half-life of 150-180 hours within PBMCs.
- Dosing in mass balance studies: FTC (single dose administration of [14C] emtricitabine after multiple dosing of emtricitabine for ten days); TAF (single dose administration of [14C] tenofovir alafenamide).
|
Table 6 Multiple Dose Pharmacokinetic Parameters of Emtricitabine, Rilpivirine, Tenofovir Alafenamide and its Metabolite Tenofovir Following Oral Administration with a Meal in Adults with HIV-1
| Parameter Mean (CV%) |
Emtricitabinea |
Rilpivirineb |
Tenofovir Alafenamidec |
Tenofovird |
| Cmax (microgram per mL) |
2.1 (20.2) |
NA |
0.16 (51.1) |
0.02 (26.1) |
| AUCtau (microgram•hour per mL) |
11.7 (16.6) |
2.2 (38.1) |
0.21 (71.8) |
0.29 (27.4) |
| Ctrough (microgram per mL) |
0.10 (46.7) |
0.08 (44.3) |
NA |
0.01 (28.5) |
|
CV = Coefficient of Variation; NA = Not Applicable
- From Intensive PK analysis in a phase 2 trial in adults with HIV-1 treated with FTC+TAF with EVG+COBI (n=19).
- From Population PK analysis in a trial of treatment-naïve adults with HIV-1 treated with RPV (n=679).
- From Population PK analysis in two trials of treatment-naïve adults with HIV-1 treated within EVG+COBI+FTC+TAF (n=539).
- From Population PK analysis in two trials of treatment-naïve adults with HIV-1 treated with EVG+COBI+FTC+TAF (n=841).
|
Specific Populations
Geriatric Patients
The pharmacokinetics of FTC and TAF have not been fully evaluated in the elderly (65 years of age and older). Population pharmacokinetics analysis of participants with HIV-1 in Phase 2 and Phase 3 trials of FTC+TAF with EVG+COBI showed that age did not have a clinically relevant effect on exposures of TAF up to 75 years of age.
The pharmacokinetics of RPV have not been fully evaluated in the elderly (65 years of age and older) [see Use in Specific Populations (8.5)].
Pediatric Patients
Exposures of TAF in 24 pediatric participants with HIV-1 aged 12 to less than 18 years who received FTC+TAF with EVG+COBI were decreased (23% for TAF AUC) compared to exposures achieved in treatment-naïve adults following administration of FTC+TAF with EVG+COBI. These exposure differences are not thought to be clinically significant based on exposure-response relationships. FTC exposures were similar in adolescents compared to treatment-naïve adults.
Exposures of FTC, TAF and TFV in 23 pediatric participants with HIV-1 aged 6 to less than 12 years who received FTC+TAF with EVG+COBI were higher (50 to 80% for AUC) than exposures achieved in adults following the administration of FTC+TAF with EVG+COBI, however, the increase was not considered clinically significant as the safety profiles were similar in adult and pediatric participants.
The PK of RPV in pediatric participants with HIV aged 6 to less than 18 years who received RPV 25 mg once daily were comparable to or slightly higher than those obtained in adults with HIV-1 [see Use In Specific Populations (8.4)].
Race and Gender
No clinically significant changes in the pharmacokinetics of the components of ODEFSEY have been observed based on race or gender.
Patients with Renal Impairment
Rilpivirine: Population pharmacokinetic analysis indicated that RPV exposure was similar in participants with HIV-1 and eGFR 60 to 89 mL per minute by Cockcroft- Gault method, relative to participants with HIV-1 and normal renal function. There is limited or no information regarding the pharmacokinetics of RPV in patients with moderate or severe renal impairment or in patients with end-stage renal disease [see Use in Specific Populations (8.6)].
Emtricitabine and Tenofovir Alafenamide: The pharmacokinetics of FTC+TAF with EVG+COBI in participants with HIV-1 and renal impairment (eGFR 30 to 69 mL per minute by Cockcroft-Gault method), and in participants with HIV-1 and ESRD (estimated creatinine clearance of less than 15 mL per minute by Cockcroft-Gault method) receiving chronic hemodialysis were evaluated in subsets of virologically- suppressed participants in open-label trials. The pharmacokinetics of TAF were similar among healthy participants, participants with HIV-1 and mild or moderate renal impairment, and participants with HIV-1 and ESRD receiving chronic hemodialysis; increases in FTC and TFV exposures in participants with HIV-1 and renal impairment were not considered clinically relevant (Table 7).
Table 7 Pharmacokinetics of FTC and a Metabolite of TAF (Tenofovir) in Adults with HIV-1 and Renal Impairment as Compared to Participants with Normal Renal Function
|
AUCtau (microgram-hour per mL)
Mean (CV%) |
| Estimated Creatinine Clearancea |
≥90 mL per
minute (N=18)b |
60–89 mL
per minute (N=11)c |
30–59 mL
per minute (N=18)d |
<15 mL
per minute (N=12)e |
| Emtricitabine |
11.4 (11.9) |
17.6 (18.2) |
23.0 (23.6) |
62.9 (48.0)f |
| Tenofovir |
0.32 (14.9) |
0.46 (31.5) |
0.61 (28.4) |
8.72 (39.4)g |
- By Cockcroft-Gault method.
- From a phase 2 trial in adults with HIV-1 and normal renal function treated with FTC+TAF with EVG+COBI.
- These participants had an eGFR ranging from 60 to 69 mL per minute.
- From a phase 3 trial in adults with HIV-1 and renal impairment treated with FTC+TAF with EVG+COBI.
- From a phase 3 trial in adults with HIV-1 and ESRD receiving chronic hemodialysis treated with FTC+TAF with EVG+COBI; PK assessed prior to hemodialysis following 3 consecutive daily doses of FTC+TAF with EVG+COBI.
- N=11.
- N=10.
|
Patients with Hepatic Impairment
Emtricitabine: The pharmacokinetics of FTC have not been studied in participants with hepatic impairment; however, FTC is not significantly metabolized by liver enzymes, so the impact of hepatic impairment should be limited.
Rilpivirine: In a study comparing 8 participants with mild hepatic impairment (Child- Pugh score A) to 8 matched controls and 8 participants with moderate hepatic impairment (Child-Pugh score B) to 8 matched controls, the multiple-dose exposure of RPV was 47% higher in participants with mild hepatic impairment and 5% higher in participants with moderate hepatic impairment [see Use in Specific Populations (8.7)].
Tenofovir Alafenamide: Clinically relevant changes in the pharmacokinetics of tenofovir alafenamide or its metabolite tenofovir were not observed in participants with mild, moderate (Child-Pugh A and B), or severe hepatic impairment (Child-Pugh C) [see Use in Specific Populations (8.7)].
Hepatitis B and/or Hepatitis C Virus Coinfection
The pharmacokinetics of FTC and TAF have not been fully evaluated in participants with hepatitis B and/or C virus. Population pharmacokinetic analysis indicated that hepatitis B and/or C virus coinfection had no clinically relevant effect on the exposure of RPV.
Pregnancy and Postpartum
Rilpivirine: The exposure (C0h and AUC24h) to total RPV after intake of RPV 25 mg once daily as part of an antiretroviral regimen was 30 to 40% lower during pregnancy (similar for the second and third trimester), compared with postpartum (see Table 8). However, the exposure during pregnancy was not significantly different from exposures obtained in Phase 3 trials of RPV-containing regimens.
Based on the exposure-response relationship for RPV, this decrease is not considered clinically relevant in patients who are virologically-suppressed. The protein binding of RPV was similar (>99%) during the second trimester, third trimester, and postpartum.
Table 8 Pharmacokinetic Results of Total Rilpivirine After Administration of Rilpivirine 25 mg Once Daily as Part of an Antiretroviral Regimen, During the 2nd Trimester of Pregnancy, the 3rd Trimester of Pregnancy and Postpartum
| Pharmacokinetics of total rilpivirine (mean ± SD, tmax: median [range]) |
Postpartum
(6-12 Weeks)
(n=11) |
2nd Trimester
of pregnancy
(n=15) |
3rd Trimester
of pregnancy
(n=13) |
| C0h, ng/mL |
111 ± 69.2 |
65.0 ± 23.9 |
63.5 ± 26.2 |
| Cmin, ng/mL |
84.0 ± 58.8 |
54.3 ± 25.8 |
52.9 ± 24.4 |
| Cmax, ng/mL |
167 ± 101 |
121 ± 45.9 |
123 ± 47.5 |
| tmax, h |
4.00 (2.03-25.08) |
4.00 (1.00-9.00) |
4.00 (2.00-24.93) |
| AUC24h, ng.h/mL |
2714 ± 1535 |
1792 ± 711 |
1762 ± 662 |
Drug Interaction Studies
Rilpivirine: RPV is primarily metabolized by CYP3A, and drugs that induce or inhibit CYP3A may thus affect the clearance of RPV.
RPV at a dose of 25 mg once daily is not likely to have a clinically relevant effect on the exposure of medicinal products metabolized by CYP enzymes.
TAF is not an inhibitor of CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, or UGT1A1. TAF is a weak inhibitor of CYP3A in vitro. TAF is not an inhibitor or inducer of CYP3A in vivo.
The drug interaction studies described in Tables 9-12 were conducted with ODEFSEY (FTC/RPV/TAF) or the components of ODEFSEY (FTC, RPV, or TAF) administered individually.
The effects of coadministered drugs on the exposures of RPV and TAF are shown in Tables 9 and 10, respectively. The effects of RPV and TAF on the exposure of coadministered drugs are shown in Tables 11 and 12, respectively. For information regarding clinical recommendations, see Drug Interactions (7).
Table 9 Changes in Pharmacokinetic Parameters for RPV in the Presence of Coadministered Drugs in Healthy Participants
| Coadministered Drug |
Dose/Schedule |
N |
Mean Ratio of RPV Pharmacokinetic Parameters With/Without Coadministered Drug (90% CI); No Effect = 1.00 |
| Coadministered Drug (mg) |
RPV (mg) |
Cmax |
AUC |
Cmin |
| Acetaminophen |
500 single dose |
150 once dailya |
16 |
1.09 (1.01, 1.18) |
1.16 (1.10, 1.22) |
1.26 (1.16, 1.38) |
| Atorvastatin |
40 once daily |
150 once dailya |
16 |
0.91 (0.79, 1.06) |
0.90 (0.81, 0.99) |
0.90 (0.84, 0.96) |
| Chlorzoxazone |
500 single dose taken 2 hours after RPV |
150 once dailya |
16 |
1.17 (1.08, 1.27) |
1.25 (1.16, 1.35) |
1.18 (1.09, 1.28) |
| Ethinylestradiol/ Norethindrone |
0.035 once daily /1 mg once daily |
25 once dailyb |
15 |
↔c |
↔c |
↔c |
| Famotidine |
40 single dose taken 12 hours before RPV |
150 single dosea |
24 |
0.99 (0.84, 1.16) |
0.91 (0.78, 1.07) |
NA |
| Famotidine |
40 single dose taken 2 hours before RPV |
150 single dosea |
23 |
0.15 (0.12, 0.19) |
0.24 (0.20, 0.28) |
NA |
| Famotidine |
40 single dose taken 4 hours after RPV |
150 single dosea |
24 |
1.21 (1.06, 1.39) |
1.13 (1.01, 1.27) |
NA |
| Ketoconazole |
400 once daily |
150 once dailya |
15 |
1.30 (1.13, 1.48) |
1.49 (1.31, 1.70) |
1.76 (1.57, 1.97) |
| Methadone |
60-100 once daily, individualized dose |
25 once dailyb |
12 |
↔c |
↔c |
↔c |
| Ledipasvir/ Sofosbuvir |
90/400 once daily |
25 once dailyd |
42 |
0.97 (0.92, 1.02) |
0.95 (0.91, 0.98) |
0.93 (0.89, 0.97) |
| Omeprazole |
20 once daily |
25 single doseb |
15 |
0.30 (0.24, 0.38) |
0.35 (0.28, 0.44) |
NA |
| Rifabutin |
300 once daily |
25 once dailyb |
18 |
0.69 (0.62, 0.76) |
0.58 (0.52, 0.65) |
0.52 (0.46, 0.59) |
| Rifampin |
600 once daily |
150 once dailya |
16 |
0.31 (0.27, 0.36) |
0.20 (0.18, 0.23) |
0.11 (0.10, 0.13) |
| Simeprevir |
25 once daily |
150 once dailyb |
23 |
1.04 (0.95, 1.30) |
1.12 (1.05, 1.19) |
1.25 (1.16, 1.35) |
| Sildenafil |
50 single dose |
75 once dailya |
16 |
0.92 (0.85, 0.99) |
0.98 (0.92, 1.05) |
1.04 (0.98, 1.09) |
| Sofosbuvir/ velpatasvir |
400/100 once daily |
10 once dailye |
24 |
0.93 (0.88,0.98) |
0.95 (0.90, 1.00) |
0.96 (0.90,1.03) |
| Sofosbuvir/velpatas vir/ voxilaprevir |
400/100/100 + 100 voxilaprevirf once daily |
25 once dailyd |
30 |
0.79 (0.74, 0.84) |
0.80 (0.76, 0.85) |
0.82 (0.77, 0.87) |
|
CI=Confidence Interval; N=maximum number of participants with data; NA=Not Available; ↔=no change
- 25 mg, 75 mg, and 150 mg of RPV is 1, 3, and 6 times the recommended dose of RPV in ODEFSEY, respectively.
- Study conducted with RPV.
- Comparison based on historic controls.
- Study conducted with ODEFSEY (FTC/RPV/TAF).
- Study conducted with FTC/RPV/TDF.
- Study conducted with additional voxilaprevir 100 mg to achieve voxilaprevir exposures expected in HCV patients.
|
Table 10 Changes in Pharmacokinetic Parameters for TAF in the Presence of the Coadministered Drug in Healthy Participants
| Coadministered Drug |
Dose of Coadministered Drug (mg) |
TAF (mg) |
N |
Mean Ratio of Tenofovir Alafenamide Pharmacokinetic Parameters (90% CI); No Effect = 1.00 |
| Cmax |
AUC |
Cmin |
| Cobicistata |
150 once daily |
8 once daily |
12 |
2.83 |
2.65 |
NA |
|
(2.20, 3.65) |
(2.29, 3.07) |
| Ledipasvir/ |
90/400 once daily |
25 once dailyb |
42 |
1.03 |
1.32 |
NA |
| Sofosbuvir |
|
(0.94, 1.14) |
(1.25, 1.40) |
| Sofosbuvir/ velpatasvir/ voxilaprevir |
400/100/100 + 100 voxilaprevirc once daily |
25 once dailyb |
30 |
1.32 (1.17, 1.48) |
1.52 (1.43,1.61) |
NA |
|
CI=Confidence Interval; N=maximum number of participants with data; NA=Not Available
- Increases TAF exposure via inhibition of intestinal P-
- Study conducted with ODEFSEY (FTC/RPV/TAF).
- Study conducted with additional voxilaprevir 100 mg to achieve voxilaprevir exposures expected in patients with
|
Table 11 Changes in Pharmacokinetic Parameters for Coadministered Drugs in the Presence of RPV in Healthy Participants
| Coadministered Drug |
Dose/Schedule |
N |
Mean Ratio of Coadministered Drug Pharmacokinetic Parameters With/Without RPV (90% CI);
No Effect = 1.00 |
| Coadministered Drug (mg) |
RPV (mg) |
Cmax |
AUC |
Cmin |
| Acetaminophen |
500 single dose |
150 once dailya |
16 |
0.97 (0.86, 1.10) |
0.92 (0.85, 0.99) |
NA |
| Atorvastatin |
|
|
|
1.35 |
1.04 |
0.85 |
|
|
|
|
(1.08, 1.68) |
(0.97, 1.12) |
(0.69, 1.03) |
| 2-hydroxy- atorvastatin |
40 once daily |
150 once dailya |
16 |
1.58 (1.33, 1.87) |
1.39 (1.29, 1.50) |
1.32 (1.10, 1.58) |
| 4-hydroxy- atorvastatin |
|
|
|
1.28 (1.15, 1.43) |
1.23 (1.13, 1.33) |
NA |
| Chlorzoxazone |
500 single dose taken 2 hours after RPV |
150 once dailya |
16 |
0.98 (0.85, 1.13) |
1.03 (0.95, 1.13) |
NA |
| Digoxin |
0.5 single dose |
25 once dailyb |
22 |
1.06 (0.97, 1.17) |
0.98 (0.93, 1.04)c |
NA |
| Ethinylestradiol |
0.035 once daily |
|
|
1.17 |
1.14 |
1.09 |
| Norethindrone |
1 mg once daily |
25 once dailyb |
17 |
(1.06, 1.30) 0.94 (0.83, 1.06) |
(1.10, 1.19) 0.89 (0.84, 0.94) |
(1.03, 1.16) 0.99 (0.90, 1.08) |
| Ketoconazole |
400 once daily |
150 once |
14 |
0.85 |
0.76 |
0.34 |
| dailya |
(0.80, 0.90) |
(0.70, 0.82) |
(0.25, 0.46) |
| Ledipasvir |
90 once daily |
25 once |
41 |
1.01 |
1.02 |
1.02 |
| dailyd |
(0.97, 1.05) |
(0.97, 1.06) |
(0.98, 1.07) |
| Sofosbuvir |
|
|
|
0.96 |
1.05 |
NA |
| GS-331007f |
400 once daily |
25 once dailyd |
41 |
(0.89, 1.04) 1.08 (1.05, 1.11) |
(1.01, 1.09) 1.08 (1.06, 1.10) |
1.10 (1.07, 1.12) |
| R(-) methadone |
|
|
|
0.86 |
0.84 |
0.78 |
| S(+) methadone |
60-100 once daily, individualized dose |
25 once dailyb |
13 |
(0.78, 0.95) 0.87 |
(0.74, 0.95) 0.84 |
(0.67, 0.91) 0.79 |
|
|
|
|
(0.78, 0.97) |
(0.74, 0.96) |
(0.67, 0.92) |
| Metformin |
850 single dose |
25 once dailyb |
20 |
1.02 (0.95, 1.10) |
0.97 (0.90,1.06)e |
NA |
| Rifampin 25- desacetylrifampin |
600 once daily |
150 once dailya |
16 |
1.02 (0.93, 1.12) 1.00 (0.87, 1.15) |
0.99 (0.92, 1.07) 0.91 (0.77, 1.07) |
NA NA |
| Simeprevir |
150 once daily |
25 once |
21 |
1.10 |
1.06 |
0.96 |
| dailyb |
(0.97, 1.26) |
(0.94, 1.19) |
(0.83, 1.11) |
| Sildenafil N-desmethyl- sildenafil |
50 single dose |
75 once dailya |
16 |
0.93 (0.80, 1.08) 0.90 (0.80, 1.02) |
0.97 (0.87, 1.08) 0.92 (0.85, 0.99)c |
NA NA |
| Sofosbuvir |
|
|
|
1.09 |
1.16 |
|
| GS-331007f |
400 once daily |
25 once dailyg |
24 |
(0.95, 1.25) 0.96 |
(1.10, 1.24) 1.04 |
NA 1.12 |
|
|
|
|
(0.90, 1.01) |
(1.00, 1.07) |
(1.07, 1.17) |
| Velpatasvir |
100 once daily |
25 once |
24 |
0.96 |
0.99 |
1.02 |
| dailyg |
(0.85, 1.10) |
(0.88, 1.11) |
(0.91, 1.15) |
| Sofosbuvir GS-331007f |
400 once daily |
25 once dailyd |
30 |
0.95 (0.86, 1.05) |
1.01 (0.97, 1.06) |
NA |
| 1.02 (0.98, 1.06) |
1.04 (1.01, 1.06) |
NA |
| Velpatasvir |
100 once daily |
25 once |
30 |
1.05 |
1.01 |
1.01 |
| dailyd |
(0.96, 1.16) |
(0.94, 1.07) |
(0.95, 1.09) |
| Voxilaprevir |
100 + 100 once daily |
25 once |
30 |
0.96 |
0.94 |
1.02 |
| dailyd |
(0.84, 1.11) |
(0.84, 1.05) |
(0.92, 1.12) |
|
CI=Confidence Interval; N=maximum number of participants with data; NA=Not Available
- 25 mg, 75 mg, and 150 mg of RPV is 1, 3, and 6 times the recommended dose of RPV in , respectively.
- Study conducted with RPV.
- AUC(0-last).
- Study conducted with ODEFSEY (FTC/RPV/TAF).
- N (maximum number of participants with data for AUC(0-∞)=15)
- The predominant circulating nucleoside metabolite of sofosbuvir.
- Study conducted with FTC/RPV/TDF.
|
Table 12 Changes in Pharmacokinetic Parameters for Coadministered Drug in the Presence of TAF in Healthy Participants
| Coadministered Drug |
Dose of Coadministered Drug (mg) |
TAF (mg) |
N |
Mean Ratio of Coadministered Drug Pharmacokinetic Parameters (90% CI);
No Effect = 1.00 |
| Cmax |
AUC |
Cmin |
| Midazolama |
2.5 single dose, orally |
25 once dailyb |
18 |
1.02 (0.92, 1.13) |
1.13 (1.04, 1.23) |
NA |
| 1 single dose, IV |
0.99 (0.89, 1.11) |
1.08 (1.04, 1.13) |
NA |
| Ledipasvirc |
90/400 once daily |
25 once dailyc |
41 |
1.01 (0.97, 1.05) |
1.02 (0.97, 1.06) |
1.02 (0.98,1.07) |
| Sofosbuvirc |
0.96 (0.89, 1.04) |
1.05 (1.01, 1.09) |
NA |
| GS-331007c,d |
1.08 (1.05, 1.11) |
1.08 (1.06, 1.10) |
1.10 (1.07, 1.12) |
| Norelgestromin |
norgestimate 0.180/0.215/0.250 once daily/ethinyl estradiol 0.025 once daily |
25 once dailye |
29 |
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 (0.93,1.12) |
| Sofosbuvir |
400 once daily |
25 once dailyc |
30 |
0.95 (0.86, 1.05) |
1.01 (0.97, 1.06) |
NA |
| GS-331007d |
1.02 (0.98, 1.06) |
1.04 (1.01, 1.06) |
NA |
| Velpatasvir |
100 once daily |
1.05 (0.96, 1.16) |
1.01 (0.94, 1.07) |
1.01 (0.95,1.09) |
| Voxilaprevir |
100 + 100 once daily |
0.96 (0.84, 1.11) |
0.94 (0.84, 1.05) |
1.02 (0.92,1.12) |
|
CI=Confidence Interval; N=maximum number of participants with data; NA=Not Available
- A sensitive CYP3A4 substrate.
- Study conducted with TAF.
- Study conducted with ODEFSEY (FTC/RPV/TAF).
- The predominant circulating nucleoside metabolite of sofosbuvir.
- Study conducted with FTC/TAF.
|
Microbiology
Mechanism of Action
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 (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, ?, and mitochondrial DNA polymerase γ.
Rilpivirine: RPV is a diarylpyrimidine non-nucleoside reverse transcriptase inhibitor of HIV-1 and inhibits HIV-1 replication by non-competitive inhibition of HIV-1 RT. RPV does not inhibit the human cellular DNA polymerases a, b, and mitochondrial DNA polymerase g.
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 has activity against human immunodeficiency virus (HIV-1). Cell culture studies have shown that both tenofovir and FTC can be fully phosphorylated when combined in cells. Tenofovir diphosphate is a weak inhibitor of mammalian DNA polymerases that include mitochondrial DNA polymerase γ and there is no evidence of toxicity to mitochondria cell culture.
Antiviral Activity in Cell Culture
Emtricitabine, Rilpivirine, and Tenofovir Alafenamide: The combinations of FTC, RPV, and TAF were not antagonistic with each other in cell culture combination antiviral activity assays. In addition, FTC, RPV, and TAF were not antagonistic with a panel of representatives from the major classes of approved anti-HIV agents (NNRTIs, NRTIs, INSTIs, and PIs).
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 primary peripheral blood mononuclear cells (PBMCs). The EC50 values for FTC were in the range of 1.3–640 nM. FTC displayed antiviral activity in cell culture against HIV-1 clades A, B, C, D, E, F, and G (EC50 values ranged from 7–75 nM) and showed strain-specific activity against HIV-2 (EC50 values ranged from 7–1500 nM).
Rilpivirine: RPV exhibited activity against laboratory strains of wild-type HIV-1 in an acutely infected T-cell line with a median EC50 value for HIV-1IIIB of 0.73 nM. RPV demonstrated limited activity in cell culture against HIV-2 with a median EC50 value of 5220 nM (range 2510–10,830 nM). RPV demonstrated antiviral activity against a broad panel of HIV-1 group M (subtype A, B, C, D, F, G, H) primary isolates with EC50 values ranging from 0.07–1.01 nM and was less active against group O primary isolates with EC50 values ranging from 2.88–8.45 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 2.0–14.7 nM.
TAF displayed antiviral activity in cell culture against all HIV-1 groups (M, N, O), including sub-types A, B, C, D, E, F, and G (EC50 values ranged from 0.10–12.0 nM) and strain specific activity against HIV-2 (EC50 values ranged from 0.91–2.63 nM).
Resistance
In Cell Culture
Emtricitabine: HIV-1 isolates with reduced susceptibility to FTC were selected in cell culture. Reduced susceptibility to FTC was associated with M184V or I substitutions in HIV-1 RT.
Rilpivirine: RPV-resistant strains were selected in cell culture starting from wild-type HIV-1 of different origins and subtypes as well as NNRTI-resistant HIV-1. The frequently observed amino acid substitutions that emerged and conferred decreased phenotypic susceptibility to RPV included: L100I, K101E, V106I and A, V108I, E138K and G, Q, R, V179F and I, Y181C and I, V189I, G190E, H221Y, F227C, and M230I and L.
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 Participants With HIV-1 and No Antiretroviral Treatment History
Emtricitabine and Tenofovir Alafenamide: The resistance profile of ODEFSEY for the treatment of HIV-1 is based on studies of FTC+TAF with EVG+COBI in the treatment of HIV-1. In a pooled analysis of antiretroviral-naïve participants, genotyping was performed on plasma HIV-1 isolates from all participants with HIV-1 RNA greater than 400 copies per mL at confirmed virologic failure, at Week 48, or at time of early study drug discontinuation. Genotypic resistance developed in 7 of 14 evaluable participants. The resistance–associated substitutions that emerged were M184V/I (N=7) and K65R (N=1). Three participants had virus with emergent R, H, or E at the polymorphic Q207 residue in reverse transcriptase.
Rilpivirine: In the Week 96 pooled resistance analysis for adult participants receiving RPV or efavirenz in combination with FTC/TDF, the emergence of resistance was greater among participants’ viruses in the RPV+FTC/TDF arm compared to the efavirenz+FTC/TDF arm and was dependent on baseline viral load. In the Week 96 resistance analysis, 14% (77/550) of the participants in the RPV+FTC/TDF arm and 8% (43/546) of the participants in the efavirenz+FTC/TDF arm qualified for resistance analysis; 61% (47/77) of the participants who qualified for resistance analysis (resistance-analysis participants) in the RPV+FTC/TDF arm had virus with genotypic and/or phenotypic resistance to RPV compared to 42% (18/43) of the resistance-analysis participants in the efavirenz+FTC/TDF arm who had genotypic and/or phenotypic resistance to efavirenz. Moreover, genotypic and/or phenotypic resistance to emtricitabine or tenofovir emerged in viruses from 57% (44/77) of the resistance-analysis participants in the RPV arm compared to 26% (11/43) in the efavirenz arm.
Emerging NNRTI substitutions in the RPV resistance analysis of participants’ viruses included V90I, K101E/P/T, E138K/A/Q/G, V179I/L, Y181C/I, V189I, H221Y, F227C/L, and M230L, which were associated with an RPV phenotypic fold change range of 2.6–621. The E138K substitution emerged most frequently during RPV treatment, commonly in combination with the M184I substitution. The emtricitabine and lamivudine resistance-associated substitutions M184I or V and NRTI resistance- associated substitutions (A62V, K65R/N, D67N/G, K70E, Y115F, K219E/R) emerged more frequently in the RPV resistance-analysis participants than in efavirenz resistance-analysis participants.
NNRTI- and NRTI-resistance substitutions emerged less frequently in the resistance analysis of viruses from participants with baseline viral loads of less than or equal to 100,000 copies/mL compared to viruses from participants with baseline viral loads of greater than 100,000 copies/mL: 23% (10/44) compared to 77% (34/44) of NNRTI- resistance substitutions and 20% (9/44) compared to 80% (35/44) of NRTI- resistance substitutions. This difference was also observed for the individual emtricitabine/lamivudine and tenofovir resistance substitutions: 22% (9/41) compared to 78% (32/41) for M184I/V and 0% (0/8) compared to 100% (8/8) for K65R/N. Additionally, NNRTI and/or NRTI-resistance substitutions emerged less frequently in the resistance analysis of the viruses from participants with baseline CD4+ cell counts greater than or equal to 200 cells/mm3 compared to the viruses from participants with baseline CD4+ cell counts less than 200 cells/mm3: 32% (14/44) compared to 68% (30/44) of NNRTI-resistance substitutions and 27% (12/44) compared to 73% (32/44) of NRTI-resistance substitutions.
In Virologically-Suppressed Participants
Emtricitabine and Tenofovir Alafenamide: One participant was identified with emergent resistance to FTC or TAF (M184M/I) out of 4 virologic failure participants in a clinical study of virologically-suppressed participants who switched from a regimen containing FTC+TDF to FTC+TAF with EVG+COBI (N=799).
Rilpivirine: Through Week 48, 4 participants who switched their protease inhibitor- based regimen to FTC/RPV/TDF (4 of 469 participants, 0.9%) and 1 participant who maintained their regimen (1 of 159 participants, 0.6%) developed genotypic and/or phenotypic resistance to a study drug. All 4 of the participants who had resistance emergence on FTC/RPV/TDF had evidence of FTC resistance and 3 of the participants had evidence of RPV resistance.
ODEFSEY: Through Week 48, in participants who switched to ODEFSEY from FTC/RPV/TDF or EFV/FTC/TDF (Trials 1216 (N=316) and 1160 (N=438),
respectively), of seven participants who developed virologic failure, three participants had detectable NNRTI and/or NRTI resistance substitutions at virologic failure that were pre-existing in the baseline sample by proviral DNA sequencing; one of these participants resuppressed while maintaining ODEFSEY.
Cross-Resistance
Emtricitabine: FTC-resistant viruses with the M184V/I substitution were cross-resistant to lamivudine, but retained sensitivity to didanosine, stavudine, tenofovir, and zidovudine.
Viruses harboring substitutions conferring reduced susceptibility to stavudine and zidovudine—thymidine analog substitutions (M41L, D67N, K70R, L210W, T215Y/F, K219Q/E), or didanosine (L74V) remained sensitive to FTC. HIV-1 containing the K103N substitution or other substitutions associated with resistance to NNRTIs was susceptible to FTC.
Rilpivirine: Considering all of the available cell culture and clinical data, any of the following amino acid substitutions, when present at baseline, are likely to decrease the antiviral activity of RPV: K101E, K101P, E138A, E138G, E138K, E138R, E138Q, V179L, Y181C, Y181I, Y181V, Y188L, H221Y, F227C, M230I, M230L, and the combination of L100I+K103N.
Cross-resistance in site-directed mutant virus has been observed among NNRTIs. The single NNRTI substitutions K101P, Y181I, and Y181V conferred 52 times, 15 times, and 12 times decreased susceptibility to RPV, respectively. The combination of E138K and M184I showed 6.7 times reduced susceptibility to RPV compared to 2.8 times for E138K alone.
The K103N substitution did not show reduced susceptibility to RPV by itself. However, the combination of L100I and K103N resulted in a 7 times reduced susceptibility to RPV. In another study, the Y188L substitution resulted in a reduced susceptibility to RPV of 9 times for clinical isolates and 6 times for site-directed mutants. Combinations of 2 or 3 NNRTI resistance-associated substitutions gave decreased susceptibility to RPV (fold change range of 3.7–554) in 38% and 66% of mutants, respectively.
Cross-resistance to efavirenz, etravirine, and/or nevirapine is likely after virologic failure and development of RPV resistance.
Tenofovir Alafenamide: 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.