Clinical Trials in Adults
Adverse Reactions in Adults with No Prior Antiretroviral Treatment History
The safety profile of SYMTUZA in HIV-1 infected adults with no prior antiretroviral treatment history is based on Week 48 data from the AMBER trial, a randomized, double-blind, active-controlled trial where a total of 362 subjects received SYMTUZA once daily and 363 subjects received a combination of PREZCOBIX® (fixed-dose combination of darunavir and cobicistat) and fixed-dose combination of emtricitabine and tenofovir disoproxil fumarate (FTC/TDF).
The proportion of subjects who discontinued treatment with SYMTUZA or PREZCOBIX+FTC/TDF due to adverse events, regardless of severity, were 2% and 4% respectively.
An overview of the most frequent (occurring in at least 2% of subjects) adverse reactions irrespective of severity reported in AMBER are presented in Table 1. An overview of the most frequent laboratory abnormalities of at least Grade 2 severity reported in AMBER are presented in Table 2. Changes from baseline in lipid parameters for patients receiving SYMTUZA and those receiving PREZCOBIX + FTC/TDF are presented in Table 3.
Most adverse reactions during treatment with SYMTUZA were grade 1 or 2 in severity. One grade 3 adverse reaction was reported and no grade 4 adverse reactions were reported during treatment with SYMTUZA.
Table 1: Adverse Reactions Reported in ≥2% of HIV-1 Infected Adults With No Prior Antiretroviral Treatment History in AMBER (Week 48 Analysis) | SYMTUZA (N=362) | PREZCOBIX+FTC/TDF (N=363) |
|---|
| All Grades | At least Grade 2 | All Grades | At least Grade 2 |
|---|
| Diarrhea | 9% | 2% | 11% | 2% |
| Rash Includes pooled reported terms: dermatitis, dermatitis allergic, erythema, photosensitivity reaction, rash, rash generalized, rash macular, rash maculo-papular, rash morbilliform, rash pruritic, toxic skin eruption, urticaria | 8% | 4% | 7% | 5% |
| Nausea | 6% | 1% | 10% | 3% |
| Fatigue | 4% | 1% | 4% | 1% |
| Headache | 3% | 1% | 2% | 1% |
| Abdominal discomfort | 2% | - | 4% | <1% |
| Flatulence | 2% | <1% | 1% | - |
Adverse Reactions in Virologically-Suppressed Adults
The safety profile of SYMTUZA in virologically-suppressed HIV-1 infected adults is based on Week 48 data from 1,141 subjects in the EMERALD trial, a randomized, open-label, active-controlled trial where 763 subjects with a stable antiretroviral regimen consisting of a boosted protease inhibitor (bPI) [either darunavir once daily or atazanavir (both boosted with ritonavir or cobicistat), or lopinavir with ritonavir] combined with FTC/TDF switched to SYMTUZA, and 378 subjects who continued their treatment regimen of a bPI with FTC/TDF. Overall, the safety profile of SYMTUZA in subjects in this study was similar to that in subjects with no prior antiretroviral treatment history. The proportion of subjects who discontinued treatment with SYMTUZA due to adverse events, regardless of severity, was 1%.
Less Frequent Adverse Reactions
The following adverse reactions occurred in less than 2% of adults with no antiretroviral treatment history or virologically suppressed subjects receiving SYMTUZA, or are from studies described in the prescribing information of the individual component PREZISTA (darunavir).
Gastrointestinal Disorders: dyspepsia, pancreatitis (acute), vomiting
Skin and Subcutaneous Tissue Disorders: angioedema, pruritus, Stevens-Johnson syndrome
Metabolism and Nutrition Disorders: anorexia, diabetes mellitus, lipodystrophy
Reproductive System and Breast Disorders: gynecomastia
Musculoskeletal and Connective Tissue Disorders: myalgia, osteonecrosis
Psychiatric Disorders: abnormal dreams
Immune System Disorders: (drug) hypersensitivity, immune reconstitution inflammatory syndrome
Hepatobiliary Disorders: acute hepatitis
Laboratory Abnormalities
Table 2: Laboratory Abnormalities (Grade 2–4) Reported in ≥2% of Adults With No Prior Antiretroviral Treatment History in AMBER (Week 48 Analysis)Laboratory Parameter Grade | Limit | SYMTUZA N=362 | PREZCOBIX+FTC/TDF N=363 |
|---|
| Creatinine | | | |
| Grade 2 | >1.3 to 1.8 × ULN | 4% | 14% |
| Grade 4 | ≥3.5× ULN | <1% | 0 |
| Triglycerides | | | |
| Grade 2 | 301–500 mg/dL | 7% | 4% |
| Grade 3 | 501–1,000 mg/dL | 1% | 1% |
| Grade 4 | >1,000 mg/dL | <1% | <1% |
| Total Cholesterol | | | |
| Grade 2 | 240–<300 mg/dL | 17% | 4% |
| Grade 3 | ≥ 300 mg/dL | 2% | 1% |
| Low-Density Lipoprotein Cholesterol | | | |
| Grade 2 | 160–189 mg/dL | 9% | 4% |
| Grade 3 | ≥190 mg/dL | 5% | 1% |
| Elevated Glucose Levels | | | |
| Grade 2 | 126–250 mg/dL | 6% | 6% |
| Grade 3 | 251–500 mg/dL | <1% | 0 |
ALT and/or AST elevations (Grade 2–4 combined) occurred in 2% of adult subjects receiving SYMTUZA with no antiretroviral treatment history in AMBER (Week 48 Analysis). Results were consistent in subjects receiving PREZCOBIX+FTC/TDF.
Table 3: Lipid Values, Mean Change from Baseline, Reported in Adults With No Prior Antiretroviral Treatment History in AMBER (Week 48 Analysis) | SYMTUZA N=362 | PREZCOBIX+FTC/TDF N=363 |
|---|
| Baseline | Week 48 | Baseline | Week 48 |
|---|
| Mean The change from baseline is the mean of within-subject changes from baseline for subjects with both baseline and Week 48 values, or the last value carried forward prior to initiating lipid-lowering agent post-baseline. | mg/dL | Change | mg/dL | Change |
|---|
| N N corresponds to the number of subjects with paired values and not on a lipid-lowering agent at screening/baseline. Subjects on lipid-lowering agents at screening/baseline were excluded from the analysis (6 out of 362 subjects on SYMTUZA, 8 out of 363 subjects on PREZCOBIX+FTC/TDF). Subjects initiating a lipid-lowering agent post-baseline had their last fasted on-treatment value (prior to starting the agent) carried forward (6 on SYMTUZA, 2 on PREZCOBIX+FTC/TDF). | N=304 One subject did not have a Week 48 result for LDL cholesterol (n=303). | N=290 |
|---|
| Total cholesterol | 168 | +30 | 164 | +11 |
| HDL cholesterol | 45 | +6 | 44 | +2 |
| LDL cholesterol | 100 | +19 | 98 | +5 |
| Triglycerides | 117 | +34 | 112 | +21 |
| Total cholesterol to HDL ratio | 4.1 | 0.2 | 4.0 | 0.1 |
The percentage of subjects starting any lipid lowering drug during treatment in the SYMTUZA and PREZCOBIX + FTC/TDF arm were 1.7% (n=6) and 0.6% (n=2), respectively.
Renal Laboratory Tests
In the AMBER trial, which enrolled 725 adults with no prior antiretroviral treatment history, subjects had a median baseline eGFR (estimated glomerular filtration rate) of 119 mL/min (SYMTUZA) and 118 mL/min (PREZCOBIX + FTC/TDF). From baseline to Week 48, mean (SD) serum creatinine increased by 0.05 (0.10) mg/dL in the SYMTUZA group and by 0.09 (0.11) mg/dL in the PREZCOBIX + FTC/TDF group. Median serum creatinine was 0.90 mg/dL (SYMTUZA) and 0.89 mg/dL (PREZCOBIX + FTC/TDF) at baseline and 0.95 mg/dL (SYMTUZA) and 0.97 mg/dL (PREZCOBIX +FTC/TDF) at Week 48. Increases in serum creatinine occurred by Week 2 of treatment and remained stable. Median urine protein-to-creatinine ratio (UPCR) was 47 mg/g (SYMTUZA) and 51 mg/g (PREZCOBIX + FTC/TDF) at baseline and 30 mg/g (SYMTUZA) and 34 mg/g (PREZCOBIX + FTC/TDF) at Week 48.
In the EMERALD trial which had 1,141 virologically-suppressed adults treated with an HIV protease inhibitor and TDF containing regimen with a median baseline eGFR of 104 mL/min (SYMTUZA) and 103 mL/min (bPI+FTC/TDF) who were randomized to continue their treatment regimen or switch to SYMTUZA, at Week 48, mean serum creatinine was similar to baseline for both those continuing baseline treatment and those switching to SYMTUZA. Mean (SD) serum creatinine was 0.98 (0.18) mg/dL (SYMTUZA) and 0.98 (0.19) mg/dL (bPI+FTC/TDF) at baseline and 0.99 (0.18) mg/dL (SYMTUZA) and 0.99 (0.21) mg/dL (bPI+FTC/TDF) at Week 48. Median serum creatinine was 0.97 mg/dL (SYMTUZA) and 0.98 mg/dL (bPI+FTC/TDF) at baseline and 1.0 mg/dL (SYMTUZA) and 0.97 mg/dL (bPI+FTC/TDF) at Week 48. Median UPCR was 62 mg/g (SYMTUZA) and 63 mg/g (bPI+FTC/TDF) at baseline and 37 mg/g (SYMTUZA) and 53 mg/g (bPI+FTC/TDF) at Week 48.
Bone Mineral Density
AMBER
The effects of SYMTUZA compared to PREZCOBIX + FTC/TDF on bone mineral density (BMD) change from baseline to Week 48 were assessed by dual-energy X-ray absorptiometry (DXA). The mean percentage change in BMD from baseline to Week 48 was −0.7% with SYMTUZA compared to −2.4% with PREZCOBIX + FTC/TDF at the lumbar spine and 0.2% compared to −2.7% at the total hip. BMD declines of 5% or greater at the lumbar spine were experienced by 16% of SYMTUZA subjects and 22% of PREZCOBIX + FTC/TDF subjects. BMD declines of 7% or greater at the femoral neck were experienced by 2% of SYMTUZA subjects and 15% of PREZCOBIX + FTC/TDF subjects. The long-term clinical significance of these BMD changes is not known.
EMERALD
In EMERALD, bPI and TDF-treated subjects were randomized to continue their TDF-based regimen or switch to SYMTUZA; changes in BMD from baseline to Week 48 were assessed by DXA. The mean percentage change in BMD from baseline to Week 48 was 1.5% with SYMTUZA compared to −0.6% with bPI + FTC/TDF at the lumbar spine and 1.4% compared to -0.3% at the total hip. BMD declines of 5% or greater at the lumbar spine were experienced by 2% of SYMTUZA subjects and 9% of bPI + FTC/TDF subjects. BMD declines of 7% or greater at the femoral neck were experienced by no SYMTUZA subjects and 2% of bPI + FTC/TDF subjects. The long-term clinical significance of these BMD changes is not known.
Clinical Trials in Pediatric Patients
Adverse Reactions in Pediatric Patients Weighing At Least 40 kg
No clinical trials with SYMTUZA were performed in pediatric patients. However, the safety of the components of SYMTUZA was evaluated in pediatric subjects of 12 to less than 18 years of age through clinical trials GS-US-216-0128 (virologically-suppressed, N=7 with weight ≥40 kg) for darunavir co-administered with cobicistat and other antiretroviral agents, and GS-US-292-0106 (treatment-naïve, N=50 with weight ≥35 kg) for a fixed-dose combination regimen containing cobicistat, emtricitabine, and tenofovir alafenamide together with elvitegravir. Safety analyses of the trials in these pediatric subjects did not identify new safety concerns compared to the known safety profile of SYMTUZA in adult subjects [see Clinical Studies (14.3)].
Metabolism and Nutrition Disorders:
redistribution of body fat
Musculoskeletal and Connective Tissue Disorders:
rhabdomyolysis (associated with co-administration with HMG-CoA reductase inhibitors)
Skin and Subcutaneous Tissue Disorders:
toxic epidermal necrolysis, acute generalized exanthematous pustulosis, drug rash with eosinophilia and systemic symptoms [see Warnings and Precautions (5.3)]
Renal and Urinary Disorders:
acute renal failure, acute tubular necrosis, proximal renal tubulopathy, and Fanconi syndrome [see Warnings and Precautions (5.6)]
Pregnancy Exposure Registry
There is a pregnancy exposure registry that monitors pregnancy outcomes in individuals exposed to SYMTUZA during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263.
Risk Summary
There are insufficient human data on the use of SYMTUZA in pregnant individuals from the APR to inform on a potential drug-associated risk of birth defects and miscarriage. Available data from the APR show no difference in rate of overall birth defects for darunavir and emtricitabine compared with the background rate for major birth defects of 2.7% in a U.S. reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP) (see Data). The rate of miscarriage is not reported in the APR. The estimated background rate of miscarriage in clinically recognized pregnancies in the U.S. general population is 15–20%. The background risk of major birth defects and miscarriage for the indicated population is unknown.
The APR uses the MACDP as the U.S. reference population for birth defects in the general population. The MACDP evaluates pregnant individuals and infants from a limited geographic area and does not include outcomes for births that occurred at less than 20 weeks' gestation.
In animal reproduction studies, no adverse developmental effects were observed when the components of SYMTUZA were administered separately at darunavir exposures less than 1- (mice and rabbits) and 2.6-times (rats) higher, at cobicistat exposures 1.7- and 4.1-times higher (rats and rabbits respectively), at emtricitabine exposures 88- and 7.3- times higher (mice and rabbits, respectively), and tenofovir alafenamide exposures equal to or 85- times higher (rats and rabbits, respectively) than human exposures at the recommended daily dose of these components in SYMTUZA (see Data). No adverse developmental effects were seen when cobicistat was administered to rats through lactation at cobicistat exposures up to 1.1 times the human exposure at the recommended therapeutic dose.
Clinical Considerations
Not Recommended During Pregnancy
SYMTUZA is not recommended for use during pregnancy because of substantially lower exposures of darunavir and cobicistat during pregnancy (see Data) and [see Clinical Pharmacology (12.3)].
SYMTUZA should not be initiated in pregnant individuals. An alternative regimen is recommended for individuals who become pregnant during therapy with SYMTUZA.
Data
Human Data
Darunavir/Cobicistat: Darunavir and cobicistat in combination with a background regimen was evaluated in a clinical trial of 7 pregnant individuals taking darunavir and cobicistat prior to enrollment and who were willing to remain on darunavir and cobicistat throughout the study. The study period included the second and third trimesters, and through 12 weeks postpartum. Six pregnant individuals completed the trial.
Exposure to darunavir and cobicistat as part of an antiretroviral regimen was substantially lower during the second and third trimesters of pregnancy compared with postpartum [see Clinical Pharmacology (12.3)].
One out of 6 pregnant individuals who completed the study experienced virologic failure with HIV-1 RNA >1,000 copies/mL from the third trimester visit through the postpartum period. Five pregnant individuals had sustained virologic response (HIV RNA <50 copies/mL) throughout the study period. There are no clinical data on the virologic response when darunavir and cobicistat are initiated during pregnancy.
Darunavir: Based on prospective reports to the APR of 679 live births following exposure to darunavir-containing regimens during pregnancy (including 425 exposed in the first trimester and 254 exposed in the second/third trimester), there was no difference in rate of overall birth defects for darunavir compared with the background rate for major birth defects in a U.S. reference population of the MACDP.
The prevalence of birth defects in live births was 2.1% (95% CI: 1.0% to 4.0%) with first trimester exposure to darunavir containing-regimens and 2.4% (95% CI: 0.9% to 5.1%) with second/third trimester exposure to darunavir-containing regimens.
Cobicistat: Insufficient numbers of pregnancies with exposure to cobicistat have been reported to the APR to estimate the rate of birth defects.
Emtricitabine: Based on prospective reports to the APR of 3749 exposures to emtricitabine-containing regimens during pregnancy (including 2614 exposed in the first trimester and 1135 exposed in the second/third trimester), there was no difference between emtricitabine and overall birth defects compared with the background birth defect rate of 2.7% in the U.S. reference population of the MACDP. The prevalence of birth defects in live births was 2.3% (95% CI: 1.8% to 2.9%) with first trimester exposure to emtricitabine-containing regimens and 2.1% (95% CI: 1.4% to 3.1%) with the second/third trimester exposure to emtricitabine-containing regimens.
Tenofovir alafenamide: Insufficient numbers of pregnancies with exposure to tenofovir alafenamide have been reported to the APR to estimate the rate of birth defects.
Animal Data
Darunavir: Reproduction studies conducted with darunavir showed no embryotoxicity or teratogenicity in mice (doses up to 1000 mg/kg from gestation day (GD) 6–15 with darunavir alone) and rats (doses up to 1000 mg/kg from GD 7–19 in the presence or absence of ritonavir) as well as in rabbits (doses up to 1000 mg/kg/day from GD 8–20 with darunavir alone). In these studies, darunavir exposures (based on AUC) were higher in rats (2.6-fold), whereas in mice and rabbits, exposures were lower (less than 1-fold) compared to those obtained in humans at the recommended daily dose of darunavir in SYMTUZA.
Cobicistat: Cobicistat was administered orally to pregnant rats at doses up to 125 mg/kg/day on GD 6–17. Increases in post-implantation loss and decreased fetal weights were observed at a maternal toxic dose of 125 mg/kg/day. No malformations were noted at doses up to 125 mg/kg/day. Systemic exposures (AUC) at 50 mg/kg/day in pregnant females were 1.7 times higher than human exposures at the recommended daily dose of cobicistat in SYMTUZA.
In pregnant rabbits, cobicistat was administered orally at doses up to 100 mg/kg/day during GD 7–20. No maternal or embryo/fetal effects were noted at the highest dose of 100 mg/kg/day. Systemic exposures (AUC) at 100 mg/kg/day were 4.1 times higher than human exposures at the recommended daily dose of cobicistat in SYMTUZA.
In a pre/postnatal developmental study in rats, cobicistat was administered orally at doses up to 75 mg/kg from GD 6 to postnatal day 20, 21, or 22. At doses of 75 mg/kg/day, neither maternal nor developmental toxicity was noted. Systemic exposures (AUC) at this dose were 1.1 times the human exposures at the recommended daily dose of cobicistat in SYMTUZA.
Emtricitabine: Emtricitabine was administered orally to pregnant mice and rabbits (up to 1000 mg/kg/day) through organogenesis (on GD 6 through 15, and 7 through 19, respectively). No significant toxicological effects were observed in embryo-fetal toxicity studies performed with emtricitabine in mice at exposures approximately 88 times higher and in rabbits approximately 7.3 times higher than human exposures at the recommended daily dose of emtricitabine in SYMTUZA.
In a pre/postnatal development study, mice were administered doses up to 1000 mg/kg/day; no significant adverse effects directly related to drug were observed in the offspring exposed daily from before birth (in utero) through sexual maturity at daily exposures of approximately 88 times higher than human exposures at the recommended daily dose of emtricitabine in SYMTUZA.
Tenofovir Alafenamide (TAF): TAF was administered orally to pregnant rats (up to 250 mg/kg/day) and rabbits (up to 100 mg/kg/day) through organogenesis (on GD 6 through 17, and 7 through 20, respectively). No adverse embryo-fetal effects were observed in rats and rabbits at TAF exposures approximately similar to (rats) and 85 times higher (rabbits) than the exposure in humans at the recommended daily dose. TAF is rapidly converted to tenofovir; the observed tenofovir exposure in rats and rabbits were 51 (rats) and 80 (rabbits) times higher than human tenofovir exposures at the recommended daily dose of TAF in SYMTUZA.
Since TAF is rapidly converted to tenofovir and a lower tenofovir exposure in rats and mice was observed after TAF administration compared to TDF (another prodrug of tenofovir) administration, a pre/postnatal development study in rats was conducted only with TDF. Doses up to 600 mg/kg/day were administered through lactation; no adverse effects were observed in the offspring on GD 7 [and lactation day 20] at tenofovir exposures of approximately 14 [21] times higher than the exposure in humans at the recommended daily dose of TDF.
Risk Summary
The Centers for Disease Control and Prevention recommend that HIV-infected mothers in the United States must not breastfeed their infants to avoid risking postnatal transmission of HIV-1 infection.
Based on published data, emtricitabine has been shown to be present in human breast milk. There are no data on the presence of darunavir, cobicistat, or TAF in human milk, the effects on the breastfed infant, or the effects on milk production. Darunavir and cobicistat are present in the milk of lactating rats. Tenofovir has been shown to be present in the milk of lactating rats and rhesus monkeys after administration of TDF (see Data). Because of the potential for (1) HIV transmission (in HIV-negative infants), (2) developing viral resistance (in HIV-positive infants), and (3) serious adverse reactions in breastfed infants, instruct mothers not to breastfeed if they are receiving SYMTUZA.
Data
Animal Data
Darunavir: Studies in rats (with darunavir alone or with ritonavir) have demonstrated that darunavir is excreted in milk. In the rat pre- and post-natal development study, a reduction in pup body weight gain was observed due to exposure of pups to drug substances via milk. The maximal maternal plasma exposures achieved with darunavir (up to 1000 mg/kg with ritonavir) were approximately 66% of those obtained in humans at the recommended clinical dose of darunavir with ritonavir.
Cobicistat: During the pre/postnatal developmental toxicology study, at doses up to 75 mg/kg/day, mean cobicistat milk to plasma ratio of up to 1.9 was measured 2 hours after administration to rats on lactation day 10.
Tenofovir Alafenamide: Studies in rats and monkeys have demonstrated that tenofovir is excreted in milk. Tenofovir was excreted into the milk of lactating rats following oral administration of TDF (up to 600 mg/kg/day) at up to approximately 24% of the median plasma concentration in the highest dosed animals at lactation day 11. Tenofovir was excreted into the milk of lactating rhesus monkeys, following a single subcutaneous (30 mg/kg) dose of tenofovir at concentrations up to approximately 4% of plasma concentration resulting in exposure (AUC) of approximately 20% of plasma exposure.
Juvenile Animal Toxicity Data
Darunavir: In a juvenile toxicity study where rats were directly dosed with darunavir (up to 1000 mg/kg), deaths occurred from post-natal day 5 at plasma exposure levels ranging from 0.1 to 1.0 of the human exposure levels. In a 4-week rat toxicology study, when dosing was initiated on post-natal day 23 (the human equivalent of 2 to 3 years of age), no deaths were observed with a plasma exposure (in combination with ritonavir) 2 times the human plasma exposure levels.
Darunavir: Darunavir, in the form of darunavir ethanolate, has the following chemical name: [(1S,2R)-3-[[(4-aminophenyl)sulfonyl](2-methylpropyl)amino]-2-hydroxy-1-(phenylmethyl)propyl]-carbamic acid (3R,3aS,6aR)-hexahydrofuro[2,3-b]furan-3-yl ester monoethanolate. Its molecular formula is C27H37N3O7S ∙ C2H5OH and its molecular weight is 593.73. Darunavir ethanolate has the following structural formula:
Chemical Structure (Symtuza 01)
Cobicistat: Cobicistat is adsorbed onto silicon dioxide. The chemical name for cobicistat is 1,3-thiazol-5-ylmethyl[(2R,5R)-5-{[(2S)-2-[(methyl{[2-(propan-2-yl)-1,3-thiazol-4-yl]methyl}carbamoyl)amino]-4-(morpholin-4yl)butanoyl]amino}-1,6-diphenylhexan-2-yl]carbamate. It has a molecular formula of C40H53N7O5S2 and a molecular weight of 776.02. It has the following structural formula:
Chemical Structure (Symtuza 02)
Emtricitabine: The chemical name of emtricitabine is 4-amino-5-fluoro-1-(2R-hydroxymethyl-[1,3]-oxathiolan-5S-yl)-(1H)-pyrimidin-2-one. Emtricitabine is the (-)enantiomer of a thio analog of cytidine, which differs from other cytidine analogs in that it has a fluorine in the 5 position. Emtricitabine has a molecular formula of C8H10FN3O3S and a molecular weight of 247.24. It has the following structural formula:
Chemical Structure (Symtuza 03)
Tenofovir alafenamide: The chemical name of tenofovir alafenamide fumarate drug substance is L-alanine, N-[(S)-[[(1R)-2-(6-amino-9H-purin-9-yl)-1-methylethoxy]methyl]phenoxyphosphinyl]-,1-methylethyl ester, (2E)-2-butenedioate (2:1). Tenofovir alafenamide fumarate has a molecular formula of C21H29O5N6P∙½(C4H4O4) and a formula weight of 534.50. It has the following structural formula:
Chemical Structure (Symtuza 04)
Cardiac Electrophysiology
Thorough QT trials have been conducted for darunavir, cobicistat, and tenofovir alafenamide. The effect of emtricitabine or the combination regimen SYMTUZA on the QT interval has not been evaluated.
Darunavir: In a thorough QT/QTc study in 40 healthy subjects, darunavir doses (co-administered with 100 mg ritonavir) of approximately 2 times the recommended darunavir dose did not affect the QT/QTc interval.
Cobicistat: In a thorough QT/QTc study in 48 healthy subjects, a single dose of cobicistat 250 mg and 400 mg (1.67 and 2.67 times the dose in SYMTUZA) did not affect the QT/QTc interval. Prolongation of the PR interval was noted in subjects receiving cobicistat. The maximum mean (95% upper confidence bound) difference in PR from placebo after baseline-correction was 9.5 (12.1) msec for the 250 mg cobicistat dose and 20.2 (22.8) for the 400 mg cobicistat dose. Because the 150 mg cobicistat dose used in the SYMTUZA fixed-dose combination tablet is lower than the lowest dose studied in the thorough QT study, it is unlikely that treatment with SYMTUZA will result in clinically relevant PR prolongation.
Tenofovir alafenamide: In a thorough QT/QTc study in 48 healthy subjects, tenofovir alafenamide at the recommended dose or at a dose approximately 5 times the recommended dose did not affect the QT/QTc interval and did not prolong the PR interval.
Effects on Serum Creatinine
The effect of cobicistat on serum creatinine was investigated in a trial in subjects with normal renal function (eGFRCG ≥80 mL/min, N=12) and mild-to-moderate renal impairment (eGFRCG 50–79 mL/min, N=18). A statistically significant decrease from baseline in the estimated glomerular filtration rate calculated by Cockcroft-Gault method (eGFRCG) was observed after 7 days of treatment with cobicistat 150 mg among subjects with normal renal function (-9.9 ± 13.1 mL/min) and mild-to-moderate renal impairment (-11.9 ± 7.0 mL/min). No statistically significant changes in eGFRCG were observed compared to baseline for subjects with normal renal function or mild-to-moderate renal impairment 7 days after cobicistat was discontinued. The actual glomerular filtration rate, as determined by the clearance of probe drug iohexol, was not altered from baseline during treatment with cobicistat among subjects with normal renal function and mild-to-moderate renal impairment, indicating that cobicistat inhibits tubular secretion of creatinine, reflected as a reduction in eGFRCG, without affecting the actual glomerular filtration rate.
Absorption, Distribution, Metabolism, and Excretion
The bioavailability of the components of SYMTUZA was not affected when administered orally as a split tablet compared to administration as a tablet swallowed whole.
Pharmacokinetic (PK) properties and PK parameters of the components of SYMTUZA are provided in Table 5 and Table 6, respectively.
Table 5: Pharmacokinetic Properties of the Components of SYMTUZA | Darunavir | Cobicistat | Emtricitabine | TAF |
|---|
| PBMCs = peripheral blood mononuclear cells; CES-1 = carboxylesterase-1 |
| Absorption |
| Tmax (h) | 3.0 | 3.0 | 1.5 | 0.5 |
| Effect of high-fat meal Approximately 928 kcal; 504 kcal from fat (56 g), 260 kcal from carbohydrates, and 164 kcal from protein. (compared to fasting) | | | | |
| AUClast LS mean ratio, 90% CI | 1.52 (1.32–1.76) | 1.41 (1.02–1.96) | 1.00 (0.96–1.04) | 1.12 (1.01–1.23) |
| Cmax LS mean ratio, 90% CI | 1.82 (1.55–2.14) | 1.30 (0.94–1.80) | 0.79 (0.71–0.89) | 0.55 (0.42–0.71) |
| Distribution |
| % bound to human plasma proteins | 95 Primarily alpha-1-acid glycoprotein | 97–98 | <4 | ~80 |
| Source of protein binding data | In vitro | In vitro | In vitro | Ex vivo |
| Blood-to-plasma ratio | 0.64 | 0.5 | 0.6 | 1.0 |
| Metabolism |
| Metabolism | CYP3A | CYP3A (major) CYP2D6 (minor) | Not significantly metabolized | Cathepsin A In 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. Upon co-administration with the moderate CYP3A inducer probe efavirenz, TAF exposure was unaffected. (PBMCs) CES1 (hepatocytes) CYP3A (minimal) |
| Elimination |
| t1/2 (h) | 9.4 | 3.2 | 7.5 | 0.5 Note that the pharmacologically active metabolite tenofovir diphosphate has a half-life of 150–180 hours within PBMCs. Tenofovir in plasma has a median elimination half-life of approximately 44 hours. |
| Major route of elimination | Metabolism | Metabolism | Glomerular filtration and active tubular secretion | Metabolism (>80% of oral dose) |
| % of dose excreted in feces Dosing in mass balance studies: darunavir (single dose administration of [14C] darunavir co-administered with multiple dose ritonavir 100 mg); cobicistat (single dose administration of [14C] cobicistat after multiple dosing of cobicistat for six days); emtricitabine (single dose administration of [14C] emtricitabine after multiple dosing of emtricitabine for ten days); TAF (single dose administration of [14C] TAF). | 79.5 Unchanged darunavir accounted for approximately 41.2% and 7.7% of the administered dose in feces and urine, respectively. | 86.2 | 13.7 | 31.7 |
| % of dose excreted in urine | 13.9 | 8.2 | 70 | <1 |
Table 6: Steady State Pharmacokinetic Parameters of Darunavir, Cobicistat, Emtricitabine, Tenofovir Alafenamide (TAF) and its Metabolite Tenofovir Following Oral Administration of SYMTUZA with Food in HIV-Infected AdultsParameter Mean (SD) | Darunavir | Cobicistat From Phase 2 PK substudy (N=21) | Emtricitabine | TAF | Tenofovir |
|---|
| Cmax, ng/mL | 8826 (33.3) | 1129 (35.3) | 2056 (25.3) | 163 (51.9) | 18.8 (37.6) |
| AUC24h, ng.h/mL | 87909 (20232) From population PK analysis in SYMTUZA Phase 3 study TMC114FD2HTX3001 in ARV naïve subjects (N=355) | 85972 (22413) From population PK analysis in SYMTUZA Phase 3 study TMC114IFD3013 in ARV experienced subjects (N=750) | 8745 (43.9) | 11918.0 (35.9) | 132 (41) | 339 (37.1) |
| C0h, ng/mL | 1899 (759) | 1813 (859) | 31 (135) | 93.1 (58.3) | NA | 11.7 (39.3) |
Specific Populations
Geriatric Patients
Darunavir: Pharmacokinetic analysis in HIV-infected subjects taking darunavir co-administered with cobicistat, emtricitabine, and tenofovir alafenamide showed no considerable differences in darunavir pharmacokinetics for ages below or equal to 65 years compared to ages greater than 65 years (N=25).
Cobicistat and Emtricitabine: The pharmacokinetics of cobicistat and emtricitabine have not been fully evaluated in the elderly (65 years of age and older).
Tenofovir alafenamide Population pharmacokinetics analysis of HIV-infected subjects in Phase 2 and Phase 3 trials of TAF combined with emtricitabine, elvitegravir, and cobicistat showed that age did not have a clinically relevant effect on exposures of TAF up to 75 years of age.
Pediatric Patients Weighing at Least 40 kg
Available pharmacokinetic data for the different components of SYMTUZA indicate that there were no clinically relevant differences in exposure between adults and pediatric subjects weighing at least 40 kg.
Darunavir and cobicistat: In pediatric subjects aged 12 to less than 18 years, weighing at least 40 kg who received darunavir 800 mg co-administered with cobicistat 150 mg (N=7), geometric mean darunavir Cmax values were similar between adults and pediatric subjects. Geometric mean darunavir AUC24h and C24h values were 15% and 32% lower, with geometric mean ratios of 0.85 (90% CI: 0.64, 1.13) and 0.68 (90% CI: 0.30, 1.55) in pediatric subjects relative to adults, respectively. These differences were not considered clinically significant. Geometric mean cobicistat AUC24h, Cmax, and C24h values were comparable in pediatric subjects and adults (Table 7).
Table 7: Multiple-Dose PK Parameters of Darunavir and Cobicistat Following Administration of Darunavir with Cobicistat in HIV 1 Infected Adults and Pediatric Subjects Weighing at least 40 kgFrom intensive PK analysis of trial GS-US-216-0128, where HIV-infected subjects were administered darunavir 800 mg and cobicistat 150 mg once daily with 2 NRTIs
| Parameter Geometric mean (CV%) | Darunavir | Cobicistat |
|---|
| CV = Coefficient of Variation; mcg = microgram |
| Pediatric Subjects | N=7 | N=7 |
| AUC24h (mcg.hr/mL) | 77.22 (29.5) | 8.33 (34.9) |
| Cmax (mcg/mL) | 7.32 (21.7) | 1.10 (20.0) |
| C24h (mcg/mL) | 0.68 (91.6) | 0.02 (123.9) N=5; Data from two subjects who had undetectable cobicistat C24h concentrations were excluded from summary statistics |
| Adults From intensive PK analysis of trial GS-US-299-0102 where HIV-infected subjects were administered SYMTUZA once daily | N=21 | N=21 |
| AUC24h (mcg.hr/mL) | 90.56 (45.3) | 7.69 (43.9) |
| Cmax (mcg/mL) | 8.34 (33.3) | 1.04 (35.3) |
| C24h (mcg/mL) | 1.00 (108.0) | 0.02 (135.1) N=18 |
Emtricitabine and tenofovir alafenamide: In 24 pediatric subjects aged 12 to less than 18 years, who received emtricitabine + TAF with elvitegravir + cobicistat, geometric mean emtricitabine Cmax, and C24h values were comparable to adults, with geometric mean ratios of 1.10 (90% CI: 0.98, 1.23) and 1.07 (90% CI: 0.88, 1.29), respectively (Table 8). Geometric mean emtricitabine AUC24h was 21% higher, with a geometric mean ratio of 1.21 (90% CI: 1.09, 1.34) in pediatric subjects relative to adults. Geometric mean tenofovir alafenamide Cmax and AUClast values were 29% and 23% lower in pediatric subjects versus adults with geometric mean ratios of 0.71 (90% CI: 0.50, 1.00) and 0.77 (90% CI: 0.59, 1.02), respectively (Table 8). The observed differences were not considered clinically significant.
Table 8: Multiple-Dose PK Parameters of Emtricitabine and Tenofovir Alafenamide Following Oral Administration with Food in HIV 1 Infected Adults and Pediatric Subjects| Parameter Geometric mean (CV%) | Emtricitabine | Tenofovir alafenamide |
|---|
| CV = Coefficient of Variation; mcg = microgram; NA = not applicable |
| Pediatric Subjects From intensive PK analysis in trial GS-US-292-0106 in treatment-naïve pediatric subjects with HIV-1 infection | N=24 | N=24 |
| AUC24h (mcg.hr/mL) AUClast for tenofovir alafenamide | 14.0 (23.9) | 0.16 (55.8) |
| Cmax (mcg/mL) | 2.2 (22.5) | 0.14 (64.4) |
| C24h (mcg/mL) | 0.10 (38.9) N=23 | NA |
| Adults From intensive PK analysis in trial GS-US-292-0102 in HIV-infected adults treated with emtricitabine+tenofovir alafenamide and elvitegravir+cobicistat | N=19 | N=19 |
| AUC24h (mcg.hr/mL) | 11.6 (16.6) | 0.21 (47.3) |
| Cmax (mcg/mL) | 2.0 (20.2) | 0.19 (64.6) |
| C24h (mcg/mL) | 0.09 (46.7) | NA |
Gender and Race
There were no clinically relevant differences in the pharmacokinetics of darunavir, cobicistat, emtricitabine, or tenofovir alafenamide based on gender or race.
Patients with Renal Impairment
Darunavir: The pharmacokinetics of darunavir were not altered in HIV-1 infected subjects with moderate renal impairment taking darunavir co-administered with ritonavir (creatinine clearance between 30–60 mL/min, estimated by Cockcroft-Gault method, N=20). There are no pharmacokinetic data available in HIV-1 infected patients with severe renal impairment or end-stage renal disease taking darunavir co-administered with cobicistat [see Use in Specific Populations (8.6)].
Cobicistat: There were no clinically relevant differences in cobicistat pharmacokinetics observed between subjects with severe renal impairment (creatinine clearance below 30 mL/min, estimated by Cockcroft-Gault method) and healthy subjects [see Use in Specific Populations (8.6)].
Emtricitabine: Mean systemic emtricitabine exposure was higher in patients with severe renal impairment (creatinine clearance less than 30 mL/min, estimated by Cockcroft-Gault method) than in subjects with normal renal function [see Use in Specific Populations (8.6)].
Tenofovir alafenamide: In studies of TAF, no clinically relevant differences in the pharmacokinetics of TAF or its metabolite tenofovir were observed between subjects with severe renal impairment (creatinine clearance of 15–30 mL/min, estimated by Cockcroft-Gault method) and healthy subjects [see Use in Specific Populations (8.6)].
Patients with Hepatic Impairment
Darunavir: There were no clinically relevant differences in the pharmacokinetics of darunavir (600 mg with ritonavir 100 mg twice daily) in subjects with mild hepatic impairment (Child-Pugh Class A, n=8), and moderate hepatic impairment (Child-Pugh Class B, n=8), compared to subjects with normal hepatic function (n=16). The effect of severe hepatic impairment on the pharmacokinetics of darunavir has not been evaluated [see Use in Specific Populations (8.7)].
Cobicistat: There were no clinically relevant differences in the cobicistat pharmacokinetics between subjects with moderate hepatic impairment (Child-Pugh Class B) and healthy subjects. The effect of severe hepatic impairment on the pharmacokinetics of cobicistat has not been evaluated [see Use in Specific Populations (8.7)].
Emtricitabine: The pharmacokinetics of emtricitabine have not been studied in subjects with hepatic impairment; however, emtricitabine is not significantly metabolized by liver enzymes, so the impact of hepatic impairment should be limited [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 patients with mild, moderate (Child-Pugh Class A and B), or severe hepatic impairment (Child-Pugh Class C); [see Use in Specific Populations (8.7)].
Patients with Hepatitis B and/or Hepatitis C Virus Coinfection
Darunavir: In HIV-infected subjects taking darunavir co-administered with ritonavir, the 48-week analysis of the data from clinical trials indicated that hepatitis B and/or hepatitis C virus coinfection status had no apparent effect on the exposure of darunavir.
Cobicistat: There were insufficient pharmacokinetic data in the clinical trials to determine the effect of hepatitis B and/or C virus infection on the pharmacokinetics of cobicistat.
Emtricitabine and tenofovir alafenamide: The pharmacokinetics of emtricitabine and tenofovir alafenamide have not been fully evaluated in subjects coinfected with hepatitis B and/or C virus.
Pregnancy and Postpartum
The exposure to total and unbound darunavir boosted with cobicistat after intake of darunavir/cobicistat as part of an antiretroviral regimen was substantially lower during the second and third trimesters of pregnancy compared with 6–12 weeks postpartum (see Table 9 and Figure 1).
Table 9: Pharmacokinetic Results of Total Darunavir after Administration of Darunavir/Cobicistat Once Daily as Part of an Antiretroviral Regimen, During the 2nd Trimester of Pregnancy, the 3rd Trimester of Pregnancy, and PostpartumPharmacokinetics of total darunavir (mean ± SD) | 2nd Trimester of pregnancy N=7 | 3rd Trimester of pregnancy N=6 | Postpartum (6–12 weeks) N=6 |
|---|
| Cmax, ng/mL | 4340 ± 1616 | 4910 ± 970 | 7918 ± 2199 |
| AUC24h, ng.h/mL | 47293 ± 19058 | 47991 ± 9879 | 99613 ± 34862 |
| Cmin, ng/mL | 168 ± 149 | 184 ± 99 | 1538 ± 1344 |
Figure 1: Pharmacokinetic Results (Within-Subject Comparison) of Total and Unbound Darunavir and Total Cobicistat After Administration of Darunavir/Cobicistat at 800/150 mg Once Daily as Part of an Antiretroviral Regimen, During the 2nd and 3rd Trimester of Pregnancy Compared to Postpartum
Legend: 90% CI: 90% confidence interval; GMR: geometric mean ratio (i.e., second or third trimester/postpartum). Solid vertical line: ratio of 1.0; dotted vertical lines: reference lines of 0.8 and 1.25.
Drug Interactions
Darunavir is metabolized by CYP3A. Cobicistat is metabolized by CYP3A and, to a minor extent, by CYP2D6. Darunavir co-administered with cobicistat is an inhibitor of CYP3A and CYP2D6. Cobicistat inhibits the following transporters: P-gp, BCRP, MATE1, OATP1B1, and OATP1B3. Based on in vitro data, cobicistat is not expected to induce CYP1A2 or CYP2B6 and based on in vivo data, cobicistat is not expected to induce MDR1 or, in general, CYP3A to a clinically significant extent. The induction effect of cobicistat on CYP2C9, CYP2C19, or UGT1A1 is unknown, but is expected to be low based on CYP3A in vitro induction data.
Emtricitabine is not an inhibitor of human CYP450 enzymes. In vitro and clinical drug interaction studies have shown that the potential for CYP-mediated interactions involving emtricitabine with other medicinal products is low. Tenofovir alafenamide is not an inhibitor of CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, or UGT1A. It is not an inhibitor or inducer of CYP3A in vivo.
Mechanism of Action
Darunavir: Darunavir is an inhibitor of the HIV-1 protease. It selectively inhibits the cleavage of HIV-1 encoded Gag-Pol polyproteins in infected cells, thereby preventing the formation of mature virus particles.
Cobicistat: Cobicistat is a selective, mechanism-based inhibitor of CYPP450 of the CYP3A subfamily. Inhibition of CYP3A-mediated metabolism by cobicistat enhances the systemic exposure of CYP3A substrates.
Emtricitabine: Emtricitabine, 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, ε, and mitochondrial DNA polymerase γ.
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 RT, which results in DNA chain-termination. 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 in cell culture.
Antiviral Activity
Darunavir: Darunavir exhibits activity against laboratory strains and clinical isolates of HIV-1 and laboratory strains of HIV-2 in acutely infected T-cell lines, human PBMCs, and human monocytes/macrophages with median EC50 values ranging from 1.2 to 8.5 nM (0.7 to 5.0 ng/mL). Darunavir demonstrates antiviral activity in cell culture against a broad panel of HIV-1 group M (A, B, C, D, E, F, G) and group O primary isolates with EC50 values ranging from less than 0.1 to 4.3 nM. The EC50 value of darunavir increases by a median factor of 5.4 in the presence of human serum.
Cobicistat: Cobicistat has no detectable antiviral activity in cell culture against HIV-1.
Emtricitabine: The antiviral activity of emtricitabine against laboratory and clinical isolates of HIV-1 was assessed in T lymphoblastoid cell lines, the MAGI-CCR5 cell line, and primary PBMCs. The EC50 values for emtricitabine were in the range of 1.3–640 nM. Emtricitabine 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 7–1,500 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 sub-types A, B, C, D, E, F, and G (EC50 values ranged from 0.10 to 12.0 nM) and strain specific activity against HIV-2 (EC50 values ranged from 0.91 to 2.63 nM).
The combination of darunavir, emtricitabine, and tenofovir alafenamide was not antagonistic in cell culture combination antiviral activity assays. In addition, darunavir, emtricitabine, and tenofovir alafenamide were not antagonistic with a panel of representative agents from the major classes of approved HIV antivirals (PIs, NRTIs, NNRTIs, and INSTIs). The antiviral activity of approved HIV antivirals was not antagonized by cobicistat.
Resistance
Cell Culture
Darunavir: In cell culture, HIV-1 isolates with a decreased susceptibility to darunavir have been selected and obtained from subjects treated with darunavir co-administered with ritonavir. Darunavir-resistant virus derived in cell culture from wild-type HIV-1 had 21- to 88-fold decreased susceptibility to darunavir and developed 2 to 4 of the following amino acid substitutions S37D, R41E/T, K55Q, H69Q, K70E, T74S, V77I, or I85V in the protease. Selection in cell culture of darunavir-resistant HIV-1 from nine HIV-1 strains harboring multiple PI resistance-associated substitutions resulted in the overall emergence of 22 mutations in the protease gene, coding for amino acid substitutions L10F, V11I, I13V, I15V, G16E, L23I, V32I, L33F, S37N, M46I, I47V, I50V, F53L, L63P, A71V, G73S, L76V, V82I, I84V, T91A/S, and Q92R, of which L10F, V32I, L33F, S37N, M46I, I47V, I50V, L63P, A71V, and I84V were the most prevalent. These darunavir-resistant viruses had at least eight protease substitutions and exhibited 50- to 641-fold decreases in darunavir susceptibility with final EC50 values ranging from 125 nM to 3461 nM.
Emtricitabine: HIV-1 isolates with reduced susceptibility to emtricitabine were selected in cell culture and in subjects treated with emtricitabine. Reduced susceptibility to emtricitabine 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.
Clinical Trials
Darunavir resistance-associated substitutions (V11I, V32I, L33F, I47V, I50V, I54L or M, T74P, L76V, I84V, and L89V) in HIV-1 protease were derived from clinical trial data of antiretroviral therapy experienced patients, which were all protease inhibitor-experienced patients. Baseline International AIDS Society-USA (IAS-USA)-defined PI resistance substitutions confer reduced virologic response to darunavir.
In the AMBER clinical trial of subjects with no prior antiretroviral treatment history, there were 7 subjects with protocol-defined virologic failure and with HIV-1 RNA ≥400 copies/mL at failure or later timepoints who had post-baseline resistance data in the SYMTUZA arm. None of the subjects had detectable emergent darunavir resistance-associated substitutions or other primary protease inhibitor resistance-associated substitutions and only one subject had emergent M184M/I/V, which confers resistance to emtricitabine and lamivudine. In the comparative PREZCOBIX + emtricitabine/tenofovir disoproxil fumarate arm, there were 2 protocol-defined virologic failures with post-baseline resistance data and neither had detectable resistance emergence.
In the EMERALD clinical trial of virologically-suppressed subjects who switched to SYMTUZA, 1 subject who rebounded and 2 subjects who discontinued early from the study had post-baseline resistance genotypes. None of the subjects had darunavir, primary protease inhibitor, emtricitabine, or tenofovir resistance-associated substitutions. In the control arm, there were 3 subjects who rebounded with post-baseline genotypes and no resistance-associated substitutions were observed.
Cross-Resistance
Darunavir: Cross-resistance among PIs has been observed. Darunavir has a less than 10-fold decreased susceptibility in cell culture against 90% of 3309 clinical isolates resistant to amprenavir, atazanavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, and/or tipranavir showing that viruses resistant to these PIs remain susceptible to darunavir. A less than 10-fold decreased susceptibility was observed for the other PIs in 26% to 96% of these PI resistant clinical isolates [nelfinavir (26%), ritonavir (34%), lopinavir (46%), indinavir (57%), atazanavir (59%), saquinavir (64%), amprenavir (70%), and tipranavir (96%)].
Cross-resistance between darunavir and nucleoside/nucleotide reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, gp41 fusion inhibitors, CCR5 co-receptor antagonists, or integrase strand transfer inhibitors is unlikely because the viral targets are different.
Emtricitabine: Emtricitabine-resistant viruses with the M184V or I substitution were cross-resistant to lamivudine, but retained sensitivity to didanosine, stavudine, tenofovir, and zidovudine.
Tenofovir Alafenamide: Tenofovir resistance-associated 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.
Darunavir: Darunavir was evaluated for carcinogenic potential by oral gavage administration to mice and rats up to 104 weeks. Daily doses of 150, 450, and 1000 mg/kg were administered to mice and doses of 50, 150, and 500 mg/kg were administered to rats. A dose-related increase in the incidence of hepatocellular adenomas and carcinomas was observed in males and females of both species and an increase in thyroid follicular cell adenomas was observed in male rats. The observed hepatocellular findings in rodents are considered to be of limited relevance to humans. Repeated administration of darunavir to rats caused hepatic microsomal enzyme induction and increased thyroid hormone elimination, which predispose rats but not humans to thyroid neoplasms. At the highest tested doses, the systemic exposures to darunavir (based on AUC) were between 0.5- and 0.6-fold (mice) and was 0.9-fold (rats) of exposures observed in humans at the recommended therapeutic dose of darunavir in SYMTUZA. Darunavir was not mutagenic or genotoxic in a battery of in vitro and in vivo assays including bacterial reverse mutation (Ames), chromosomal aberration in human lymphocytes, and in vivo micronucleus test in mice.
Cobicistat: In a long-term carcinogenicity study in mice, no drug-related increases in tumor incidence were observed at doses up to 50 and 100 mg/kg/day in males and females, respectively. Cobicistat exposures at these doses were approximately 8.6 (male) and 20 (females) times, respectively, the human systemic exposure at the therapeutic daily dose of cobicistat in SYMTUZA. In a long-term carcinogenicity study of cobicistat in rats, an increased incidence of follicular cell adenomas and/or carcinomas in the thyroid gland was observed at doses of 25 and 50 mg/kg/day in males, and at 30 mg/kg/day in females. The follicular cell findings are considered to be rat-specific, secondary to hepatic microsomal enzyme induction and thyroid hormone imbalance, and are not relevant for humans. At the highest doses tested in the rat carcinogenicity study, systemic exposures were approximately 2 times the human systemic exposure at the therapeutic daily dose of cobicistat in SYMTUZA. Cobicistat was not genotoxic in the reverse mutation bacterial test (Ames test), mouse lymphoma, or rat micronucleus assays.
Emtricitabine: In long-term carcinogenicity studies of emtricitabine, no drug-related increases in tumor incidence were found in mice at doses up to 750 mg per kg per day (26 times the human systemic exposure at the recommended dose of emtricitabine in SYMTUZA) or in rats at doses up to 600 mg per kg per day (31 times the human systemic exposure at the recommended dose). Emtricitabine was not genotoxic in the reverse mutation bacterial test (Ames test), mouse lymphoma, or mouse micronucleus assays. Emtricitabine did not affect fertility in male rats at approximately 107 times or in male and female mice at approximately 88 times higher exposures (AUC) than in humans given the recommended 200 mg daily dose in SYMTUZA. Fertility was normal in the offspring of mice exposed daily from before birth (in utero) through sexual maturity at daily exposures (AUC) of approximately 88 times higher than human exposures at the recommended 200 mg daily dose.
Tenofovir alafenamide: Since TAF is rapidly converted to tenofovir and a lower tenofovir exposure in rats and mice was observed after TAF administration compared to TDF administration, carcinogenicity studies were conducted only with TDF. Long-term oral carcinogenicity studies of TDF in mice and rats were carried out at exposures up to approximately 10 times (mice) and 4 times (rats) those observed in humans at the 300 mg therapeutic dose of TDF for HIV-1 infection. The tenofovir exposure in these studies was approximately 167 times (mice) and 55 times (rat) those observed in humans after administration of the daily recommended dose of TAF. At the high dose in female mice, liver adenomas were increased at tenofovir exposures approximately 10 times (300 mg TDF) and 167 times (10 mg TAF) the exposure observed in humans. In rats, the study was negative for carcinogenic findings.
TAF was not genotoxic in the reverse mutation bacterial test (Ames test), mouse lymphoma, or rat micronucleus assays. There were no effects on fertility, mating performance, or early embryonic development when TAF was administered to male rats at a dose equivalent to 155 times the human dose based on body surface area comparisons for 28 days prior to mating and to female rats for 14 days prior to mating through Day 7 of gestation.
Instructions for Use
Advise patients to take SYMTUZA with food every day on a regular dosing schedule, as missed doses can result in development of resistance. Inform patients not to alter the dose of SYMTUZA or discontinue therapy with SYMTUZA without consulting their physician. For patients who are unable to swallow tablets whole, SYMTUZA may be split using a tablet-cutter, and the entire dose should be consumed immediately after splitting [see Dosage and Administration (2.2)].
Post-treatment Acute Exacerbation of Hepatitis B in Patients with HBV Co-Infection
Severe acute exacerbations of hepatitis B have been reported in patients who are coinfected with HBV and HIV-1 and have discontinued products containing emtricitabine and/or TDF, and may likewise occur with discontinuation of SYMTUZA [see Warnings and Precautions (5.1)]. Advise the patient to not discontinue SYMTUZA without first informing their healthcare provider.
Hepatotoxicity
Inform patients that drug-induced hepatitis (e.g., acute hepatitis, cytolytic hepatitis) and liver injury, including some fatalities, could potentially occur with SYMTUZA. Advise patients to contact their healthcare provider immediately if signs and symptoms of liver problems develop [see Warnings and Precautions (5.2)].
Severe Skin Reactions
Inform patients that skin reactions ranging from mild to severe, including Stevens-Johnson syndrome, drug rash with eosinophilia and systemic symptoms, and toxic epidermal necrolysis, could potentially occur with SYMTUZA. Advise patients to contact their healthcare provider immediately if signs or symptoms of severe skin reactions develop, including but not limited to severe rash or rash accompanied with fever, general malaise, fatigue, muscle or joint aches, blisters, oral lesions, and/or conjunctivitis [see Warnings and Precautions (5.3)].
Pregnancy
Advise patients that SYMTUZA is not recommended during pregnancy and to alert their healthcare provider if they get pregnant while taking SYMTUZA. Inform patients that there is an antiretroviral pregnancy registry to monitor fetal outcomes of pregnant individuals exposed to SYMTUZA [see Use in Specific Populations (8.1)].
Lactation
Instruct individuals with HIV-1 infection not to breastfeed because HIV-1 can be passed to the baby in breast milk [see Use in Specific Populations (8.2)].
Drug Interactions
SYMTUZA may interact with many drugs; therefore, inform patients of the potential serious drug interactions with SYMTUZA, and that some drugs are contraindicated with SYMTUZA and other drugs may require dosage adjustment. Advise patients to report to their healthcare provider the use of any other prescription or nonprescription medication or herbal products, including St. John's wort [see Contraindications (4), Warnings and Precautions (5.4), and Drug Interactions (7)].
Immune Reconstitution Syndrome
Advise patients to inform their healthcare provider immediately of any symptoms of infection, as in some patients with advanced HIV infection (AIDS), signs and symptoms of inflammation from previous infections may occur soon after anti-HIV treatment is started [see Warnings and Precautions (5.5)].
Renal Impairment
Advise patients to avoid taking SYMTUZA with concurrent or recent use of nephrotoxic agents. Renal impairment, including cases of acute renal failure, has been reported in association with the use of tenofovir prodrugs [see Warnings and Precautions (5.6)].
Lactic Acidosis and Severe Hepatomegaly
Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with use of drugs similar to SYMTUZA. Advise patients that they should stop SYMTUZA if they develop clinical symptoms suggestive of lactic acidosis or pronounced hepatotoxicity [see Warnings and Precautions (5.8)].
Fat Redistribution
Inform patients that redistribution or accumulation of body fat may occur in patients receiving antiretroviral therapy, including SYMTUZA, and that the cause and long-term health effects of these conditions are not known at this time [see Warnings and Precautions (5.10)].
Manufactured by:
Patheon Inc
2100 Syntex Ct
Mississauga ON L5N 7K9, Canada
Or
Janssen Cilag SpA
Latina, IT
Manufactured for:
Janssen Therapeutics, Division of Janssen Products, LP, Titusville NJ 08560
© 2020 Janssen Pharmaceutical Companies