Generic Name: emtricitabine and tenofovir alafenamide fumarate
Dosage Form: tablet
Descovy is not approved for the treatment of chronic hepatitis B virus (HBV) infection, and the safety and efficacy of Descovy have not been established in patients coinfected with human immunodeficiency virus-1 (HIV-1) and HBV. Severe acute exacerbations of hepatitis B have been reported in patients who are coinfected with HIV-1 and HBV and have discontinued products containing emtricitabine (FTC) and/or tenofovir disoproxil fumarate (TDF), and may occur with discontinuation of Descovy.
Hepatic function should be monitored closely with both clinical and laboratory follow-up for at least several months in patients who are coinfected with HIV-1 and HBV and discontinue Descovy. If appropriate, initiation of anti-hepatitis B therapy may be warranted [see Warnings and Precautions (5.1)].
Indications and Usage for Descovy
Descovy is indicated, in combination with other antiretroviral agents, for the treatment of HIV-1 infection in adults and pediatric patients 12 years of age and older.
Limitations of Use:
Descovy is not indicated for use as pre-exposure prophylaxis (PrEP) to reduce the risk of sexually acquired HIV-1 in adults at high risk.
Descovy Dosage and Administration
Testing Prior to Initiation of Descovy
Prior to initiation of Descovy, patients should be tested for hepatitis B virus infection [see Warnings and Precautions (5.1)].
Estimated creatinine clearance, urine glucose, and urine protein should be assessed before initiating Descovy therapy and should be monitored during therapy in all patients [see Warnings and Precautions (5.3)].
Descovy is a two-drug fixed dose combination product containing 200 mg of emtricitabine (FTC) and 25 mg of tenofovir alafenamide (TAF). The recommended dosage of Descovy is one tablet taken orally once daily with or without food in adults and pediatric patients 12 years of age and older with body weight at least 35 kg and creatinine clearance greater than or equal to 30 mL per minute [see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3)].
For specific dosing recommendations for coadministered third agents, refer to their respective prescribing information [see Drug Interactions (7)].
Not Recommended in Patients with Severe Renal Impairment
Dosage Forms and Strengths
Each Descovy tablet contains 200 mg of emtricitabine (FTC) and 25 mg of tenofovir alafenamide (TAF) (equivalent to 28 mg of tenofovir alafenamide fumarate). The tablets are blue, rectangular-shaped, film-coated, debossed with "GSI" on one side and "225" on the other side.
Warnings and Precautions
Severe Acute Exacerbation of Hepatitis B in Patients Coinfected with HIV-1 and HBV
Patients with HIV-1 should be tested for the presence of chronic hepatitis B virus (HBV) before initiating antiretroviral therapy [see Dosage and Administration (2.1)]. Descovy is not approved for the treatment of chronic HBV infection, and the safety and efficacy of Descovy have not been established in patients coinfected with HIV-1 and HBV.
Severe acute exacerbations of hepatitis B (e.g., liver decompensation and liver failure) have been reported in patients who are coinfected with HIV-1 and HBV and have discontinued products containing FTC and/or tenofovir disoproxil fumarate (TDF), and may occur with discontinuation of Descovy. Patients coinfected with HIV-1 and HBV who discontinue Descovy should be closely monitored with both clinical and laboratory follow-up for at least several months after stopping treatment. If appropriate, initiation of anti-hepatitis B therapy may be warranted, especially in patients with advanced liver disease or cirrhosis, since post-treatment exacerbation of hepatitis may lead to hepatic decompensation and liver failure.
Immune Reconstitution Syndrome
Immune reconstitution syndrome has been reported in patients treated with combination antiretroviral therapy, including FTC, a component of Descovy. During the initial phase of combination antiretroviral treatment, patients whose immune system responds may develop an inflammatory response to indolent or residual opportunistic infections [such as Mycobacterium avium infection, cytomegalovirus, Pneumocystis jirovecii pneumonia (PCP), or tuberculosis], which may necessitate further evaluation and treatment.
Autoimmune disorders (such as Graves' disease, polymyositis, and Guillain-Barré syndrome) have also been reported to occur in the setting of immune reconstitution; however, the time to onset is more variable, and can occur many months after initiation of treatment.
New Onset or Worsening Renal Impairment
Renal impairment, including cases of acute renal failure and Fanconi syndrome (renal tubular injury with severe hypophosphatemia), has been reported with the use of tenofovir prodrugs in both animal toxicology studies and human trials. In clinical trials of FTC+TAF with cobicistat (COBI) plus elvitegravir (EVG), there have been no cases of Fanconi syndrome or Proximal Renal Tubulopathy (PRT). In clinical trials of FTC+TAF with EVG+COBI in treatment-naïve subjects and in virally suppressed subjects switched to FTC+TAF with EVG+COBI with eGFRs greater than 50 mL per minute, renal serious adverse events or discontinuations due to renal adverse reactions were encountered in less than 1% of participants treated with FTC+TAF with EVG+COBI. In a study of virally suppressed subjects with baseline eGFRs between 30 and 69 mL per minute treated with FTC+TAF with EVG+COBI for a median duration of 43 weeks, FTC+TAF with EVG+COBI was permanently discontinued due to worsening renal function in two of 80 (3%) subjects with a baseline eGFR between 30 and 50 mL per minute [see Adverse Reactions (6.1)]. Descovy is not recommended in patients with estimated creatinine clearance below 30 mL per minute because data in this population are insufficient.
Patients taking tenofovir prodrugs who have impaired renal function and those taking nephrotoxic agents including non-steroidal anti-inflammatory drugs are at increased risk of developing renal-related adverse reactions.
Estimated creatinine clearance, urine glucose, and urine protein should be assessed before initiating Descovy therapy and should be monitored during therapy in all patients. Serum phosphorus should be monitored in patients with chronic kidney disease because these patients are at greater risk of developing Fanconi syndrome on tenofovir prodrugs. Discontinue Descovy in patients who develop clinically significant decreases in renal function or evidence of Fanconi syndrome.
Lactic Acidosis/Severe Hepatomegaly with Steatosis
Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogs, including emtricitabine, a component of Descovy, and tenofovir DF, another prodrug of tenofovir, alone or in combination with other antiretrovirals. Treatment with Descovy should be suspended in any patient who develops clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity (which may include hepatomegaly and steatosis even in the absence of marked transaminase elevations).
Bone Loss and Mineralization Defects
Decrease in Bone Mineral Density (BMD):
In animal toxicology studies and human clinical trials, TAF and tenofovir have been associated with decreases in BMD and increases in biochemical markers of bone metabolism suggestive of increased bone turnover. In clinical trials in HIV-1 infected treatment-naïve adults, a significant decline in BMD was observed in 15% of subjects treated with FTC+TAF with EVG+COBI [see Adverse Reactions (6.1)]. The long-term clinical significance of these changes has not been established.
Assessment of BMD should be considered for adults and pediatric patients treated with Descovy who have a history of pathologic bone fracture or other risk factors for osteoporosis or bone loss. Calcium and vitamin D supplementation may be beneficial for all patients. If bone abnormalities are suspected, then appropriate consultation should be obtained.
Cases of osteomalacia associated with proximal renal tubulopathy, manifested as bone pain or pain in extremities and which may contribute to fractures, have been reported in association with the use of TDF-containing products. Hypophosphatemia and osteomalacia secondary to PRT have occurred in patients at risk of renal dysfunction who present with persistent or worsening bone or muscle symptoms while receiving products containing TDF [see Warnings and Precautions (5.3)]. While not observed in clinical studies of Descovy, the risk of osteomalacia with Descovy is not known.
The following adverse reactions are discussed in other sections of the labeling:
- Severe Acute Exacerbations of Hepatitis B [see Boxed Warning and Warnings and Precautions (5.1)].
- Immune Reconstitution Syndrome [see Warnings and Precautions (5.2)].
- New Onset or Worsening Renal Impairment [see Warnings and Precautions (5.3)].
- Lactic Acidosis/Severe Hepatomegaly with Steatosis [see Warnings and Precautions (5.4)]
- Bone Loss and Mineralization Defects [see Warnings and Precautions (5.5)].
Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug (or a drug given in various combinations with other concomitant therapy) cannot be directly compared to rates in the clinical trials of another drug (or drug given in the same or different combination therapy) and may not reflect the rates observed in practice.
Adverse Reactions in Clinical Trials of FTC+TAF with EVG+COBI in Treatment-Naïve Adults with HIV-1 Infection
In pooled 48-week trials of antiretroviral treatment-naïve HIV-1 infected adult subjects, the most common adverse reaction in subjects treated with FTC+TAF with EVG+COBI (N=866) (incidence greater than or equal to 10%, all grades) was nausea (10%). In this treatment group, 0.9% of subjects discontinued FTC+TAF with EVG+COBI due to adverse events during the 48-week treatment period [see Clinical Studies (14)]. The safety profile was similar in virologically-suppressed adults with HIV-1 infection who were switched to FTC+TAF with EVG+COBI (N=799). Antiretroviral treatment-naïve adult subjects treated with FTC+TAF with EVG+COBI experienced mean increases of 30 mg/dL of total cholesterol, 15 mg/dL of LDL cholesterol, 7 mg/dL of HDL cholesterol and 29 mg/dL of triglycerides after 48 weeks of use.
Renal Laboratory Tests
In two 48-week trials in antiretroviral treatment-naïve HIV-1 infected adults treated with FTC+TAF with EVG+COBI (N=866) with a median baseline eGFR of 115 mL per minute, mean serum creatinine increased by 0.1 mg per dL from baseline to Week 48. Median urine protein-to-creatinine ratio (UPCR) was 44 mg per gram at baseline and at Week 48. In a 48-week trial in virologically-suppressed TDF-treated adults who switched to FTC+TAF with EVG+COBI (N=959) with a mean baseline eGFR of 112 mL per minute, mean serum creatinine was similar to baseline and median UPCR was 61 mg per gram at baseline and 46 mg per gram at Week 48. In a 24-week trial in adults with renal impairment (baseline eGFR 30 to 69 mL per minute) who received FTC+TAF with EVG+COBI (N=248), mean serum creatinine was 1.5 mg per dL at both baseline and Week 24. Median UPCR was 161 mg per gram at baseline and 93 mg per gram at Week 24.
Bone Mineral Density Effects
In the pooled analysis of two 48-week trials of antiretroviral treatment-naïve HIV-1 infected adult subjects, bone mineral density (BMD) from baseline to Week 48 was assessed by dual-energy X-ray absorptiometry (DXA). Mean BMD decreased from baseline to Week 48 −1.30% with FTC+TAF with EVG+COBI at the lumbar spine and −0.66% at the total hip. BMD declines of 5% or greater at the lumbar spine were experienced by 10% of FTC+TAF with EVG+COBI subjects. BMD declines of 7% or greater at the femoral neck were experienced by 7% of FTC+TAF with EVG+COBI subjects. The long-term clinical significance of these BMD changes is not known. Fractures (excluding fingers and toes) were reported in 7 (0.8%) subjects in the FTC+TAF with EVG+COBI group.
In 799 virologically-suppressed TDF-treated adult subjects that switched to FTC+TAF with EVG+COBI, at Week 48 mean BMD increased (1.86% lumbar spine, 1.95% total hip). BMD declines of 5% or greater at the lumbar spine were experienced by 1% of FTC+TAF with EVG+COBI subjects. BMD declines of 7% or greater at the femoral neck were experienced by 1% of FTC+TAF with EVG+COBI subjects.
Adverse Reactions in Clinical Trials in Pediatric Subjects with HIV-1 Infection
In a 24 week, open-label trial of 23 antiretroviral treatment-naïve HIV-1 infected pediatric subjects aged 12 to less than 18 years old (weighing at least 35 kg) who received FTC+TAF with EVG+COBI, the safety of this combination was similar to that of adults. Among these pediatric subjects, mean BMD increased from baseline to Week 24, +1.7% at the lumbar spine and +0.8% for the total body less head. Mean changes from baseline BMD Z-scores were −0.10 for lumbar spine and −0.11 for total body less head at Week 24. Two subjects had significant (greater than 4%) lumbar spine BMD loss at Week 24.
Potential for Other Drugs to Affect One or More Components of Descovy
TAF, a component of Descovy, is a substrate of P-gp, BCRP, OATP1B1, and OATP1B3. Drugs that strongly affect P-gp activity may lead to changes in TAF absorption (see Table 1). Drugs that induce P-gp activity are expected to decrease the absorption of TAF, resulting in decreased plasma concentration of TAF, which may lead to loss of therapeutic effect of Descovy and development of resistance. Coadministration of Descovy with other drugs that inhibit P-gp may increase the absorption and plasma concentration of TAF. 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.
Drugs Affecting Renal Function
Because FTC and tenofovir are primarily excreted by the kidneys by a combination of glomerular filtration and active tubular secretion, coadministration of Descovy with drugs that reduce renal function or compete for active tubular secretion may increase concentrations of FTC, tenofovir, and other renally eliminated drugs and this may increase the risk of adverse reactions. Some examples of drugs that are eliminated by active tubular secretion include, but are not limited to, acyclovir, cidofovir, ganciclovir, valacyclovir, valganciclovir, aminoglycosides (e.g., gentamicin), and high-dose or multiple NSAIDs [see Warnings and Precautions (5.3)].
Established and Other Potentially Significant Interactions
Table 1 provides a listing of established or potentially clinically significant drug interactions with recommended steps to prevent or manage the drug interaction (the table is not all inclusive). The drug interactions described are based on studies conducted with either Descovy, the components of Descovy (emtricitabine and tenofovir alafenamide) as individual agents, or are predicted drug interactions that may occur with Descovy. For magnitude of interaction, see Clinical Pharmacology (12.3).
|Concomitant Drug Class: Drug Name||Effect on Concentration†||Clinical Comment|
|Antiretroviral Agents: Protease Inhibitors (PI)|
|tipranavir/ritonavir||↓ TAF||Coadministration with Descovy is not recommended.|
|↓ TAF||Consider alternative anticonvulsant.|
|↓ TAF||Coadministration of Descovy with rifabutin, rifampin, or rifapentine is not recommended.|
St. John's wort (Hypericum perforatum)
|↓ TAF||Coadministration of Descovy with St. John's wort is not recommended.|
Drugs without Clinically Significant Interactions with Descovy
Based on drug interaction studies conducted with the components of Descovy, no clinically significant drug interactions have been either observed or are expected when Descovy is combined with the following antiretroviral agents: atazanavir with ritonavir or cobicistat, darunavir with ritonavir or cobicistat, dolutegravir, efavirenz, ledipasvir, lopinavir/ritonavir, maraviroc, nevirapine, raltegravir, rilpivirine, and sofosbuvir. No clinically significant drug interactions have been either observed or are expected when Descovy is combined with the following drugs: buprenorphine, itraconazole, ketoconazole, lorazepam, methadone, midazolam, naloxone, norbuprenorphine, norgestimate/ethinyl estradiol, and sertraline.
USE IN SPECIFIC POPULATIONS
Pregnancy Exposure Registry
There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to Descovy during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263.
There are insufficient human data on the use of Descovy during pregnancy to inform a drug-associated risk of birth defects and miscarriage. Tenofovir alafenamide (TAF) use in women during pregnancy has not been evaluated; however, emtricitabine (FTC) use during pregnancy has been evaluated in a limited number of women reported to the APR. Available data from the APR show no difference in the risk of overall major birth defects for FTC (2.4%) 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). The rate of miscarriage is not reported in the APR. The estimated background rate of miscarriage in the clinically recognized pregnancies in the U.S. general population is 15−20%. In animal studies, no adverse developmental effects were observed when the components of Descovy were administered separately during the period of organogenesis at exposures 60 and 108 times (mice and rabbits, respectively) the FTC exposure and at exposure equal to or 53 times (rats and rabbits, respectively) the TAF exposure at the recommended daily dose of Descovy [see Data (8.1)]. Likewise, no adverse developmental effects were seen when FTC was administered to mice through lactation at exposures up to approximately 60 times the exposure at the recommended daily dose of Descovy. No adverse effects were observed in the offspring when TDF was administered through lactation at tenofovir exposures of approximately 14 times the exposure at the recommended daily dosage of Descovy.
Emtricitabine: Based on prospective reports to the APR through July 2015 of 2933 exposures to FTC-containing regimens during pregnancy (including 1984 exposed in the first trimester and 949 exposed in the second/third trimester), there was no difference between FTC 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 2.4% (95% CI: 1.7% to 3.1%) with first trimester exposure to FTC-containing regimens and 2.1% (95% CI: 1.3% to 3.2%) with the second/third trimester exposure to FTC-containing regimens.
Emtricitabine: FTC was administered orally to pregnant mice (250, 500, or 1000 mg/kg/day) and rabbits (100, 300, or 1000 mg/kg/day) through organogenesis (on gestation days 6 through 15, and 7 through 19, respectively). No significant toxicological effects were observed in embryo-fetal toxicity studies performed with FTC in mice at exposures (area under the curve [AUC]) approximately 60 times higher and in rabbits at approximately 108 times higher than human exposures at the recommended daily dose. In a pre/postnatal development study with FTC, 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 (AUC) of approximately 60-fold higher than human exposures at the recommended daily dose.
Tenofovir Alafenamide: TAF was administered orally to pregnant rats (25, 100, or 250 mg/kg/day) and rabbits (10, 30, or 100 mg/kg/day) through organogenesis (on gestation days 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 53 (rabbits) times higher than the exposure in humans at the recommended daily dose of Descovy. TAF is rapidly converted to tenofovir; the observed tenofovir exposures in rats and rabbits were 59 (rats) and 93 (rabbits) times higher than human tenofovir exposures at the recommended daily dose. Since TAF is rapidly converted to tenofovir and a lower tenofovir exposure in rats and mice was observed after TAF administration compared to tenofovir disoproxil fumarate (TDF, another prodrug for 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 gestation day 7 [and lactation day 20] at tenofovir exposures of approximately 14  times higher than the exposures in humans at the recommended daily dose of Descovy.
The Centers for Disease Control and Prevention recommend that HIV-infected mothers not breastfeed their infants, to avoid risking postnatal transmission of HIV.
FTC has been shown to be present in human breast milk; it is not known if TAF is present in human breast milk [see Data (8.2)]. Tenofovir has been shown to be present in the milk of lactating rats and rhesus monkeys after administration of TDF [see Data (8.2)]. It is not known if TAF can be present in animal milk. While it is not known whether TAF is present in human breast milk, FTC has been shown to be present in human breast milk [see Data (8.2)].
It is not known if Descovy affects milk production or has effects on the breastfed child. Because of the potential for: 1) HIV transmission (in HIV-negative infants); 2) developing viral resistance (in HIV-positive infants); and 3) adverse reactions in a breastfed infant similar to those seen in adults, instruct mothers not to breastfeed if they are receiving Descovy [see Data (8.2)].
Emtricitabine: Samples of breast milk obtained from five HIV-1 infected mothers show that emtricitabine is present in human milk. Breastfeeding infants whose mothers are being treated with emtricitabine may be at risk for developing viral resistance to emtricitabine. Other emtricitabine-associated risks in infants breastfed by mothers being treated with emtricitabine are unknown.
Tenofovir Alafenamide: Studies in rats and monkeys have demonstrated that tenofovir is secreted 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 [see Data (8.1)]. Tenofovir was excreted into the milk of lactating 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.
The efficacy and safety of Descovy, in combination with other antiretroviral agents, for the treatment of HIV-1 infection was established in pediatric patents aged 12 years old and older with body weight greater than or equal to 35 kg [see Dosage and Administration (2.2)]. Use of Descovy in this age group is supported by adequate and well controlled studies of FTC+TAF with EVG+COBI in adults and by a 24-week open-label trial of 23 antiretroviral treatment-naïve HIV-1 infected pediatric subjects 12 to less than 18 years old (weighing at least 35 kg) treated with FTC+TAF with EVG+COBI. The safety and efficacy of FTC+TAF with EVG+COBI was similar to that of antiretroviral treatment-naïve HIV-1 infected adults on this regimen [see Clinical Pharmacology (12.3) and Clinical Studies (14)].
Safety and effectiveness of Descovy in pediatric patients less than 12 years of age or less than 35 kg have not been established.
In clinical trials, 80 of the 97 subjects enrolled aged 65 years and over received FTC+TAF and EVG+COBI. No differences in safety or efficacy have been observed between elderly subjects and those between 12 and less than 65 years of age.
Descovy is not recommended in patients with severe renal impairment (estimated creatinine clearance below 30 mL per minute). No dosage adjustment of Descovy is recommended in patients with estimated creatinine clearance greater than or equal to 30 mL per minute [see Dosage and Administration (2.3) and Clinical Studies (14)].
No dosage adjustment of Descovy is recommended in patients with mild (Child-Pugh Class A) or moderate (Child-Pugh Class B) hepatic impairment. Descovy has not been studied in patients with severe hepatic impairment (Child-Pugh Class C) [see Clinical Pharmacology (12.3)].
No data are available on overdose of Descovy in patients. If overdose occurs, monitor the patient for evidence of toxicity. Treatment of overdose with Descovy consists of general supportive measures including monitoring of vital signs as well as observation of the clinical status of the patient.
Emtricitabine (FTC): Limited clinical experience is available at doses higher than the recommended dose of FTC in Descovy. In one clinical pharmacology study, single doses of FTC 1200 mg (6 times the FTC dose in Descovy) were administered to 11 subjects. No severe adverse reactions were reported. The effects of higher doses are not known.
Hemodialysis treatment removes approximately 30% of the FTC dose over a 3-hour dialysis period starting within 1.5 hours of FTC dosing (blood flow rate of 400 mL per minute and a dialysate flow rate of 600 mL per minute). It is not known whether FTC can be removed by peritoneal dialysis.
Tenofovir alafenamide (TAF): Limited clinical experience is available at doses higher than the recommended dose of TAF. A single dose of 125 mg TAF (5 times the TAF dose in 200/25 mg Descovy) was administered to 48 healthy subjects; no serious adverse reactions were reported. The effects of higher doses are unknown. Tenofovir is efficiently removed by hemodialysis with an extraction coefficient of approximately 54%.
Descovy (emtricitabine and tenofovir alafenamide) is a fixed dose combination tablet containing emtricitabine (FTC) and tenofovir alafenamide (TAF) for oral administration.
- FTC, a synthetic nucleoside analog of cytidine, is an HIV nucleoside analog reverse transcriptase inhibitor (HIV NRTI).
- TAF, an HIV NRTI, is converted in vivo to tenofovir, an acyclic nucleoside phosphonate (nucleotide) analog of adenosine 5′-monophosphate.
Each 200/25 mg tablet contains 200 mg of FTC and 25 mg of TAF (equivalent to 28 mg of tenofovir alafenamide fumarate) and the following inactive ingredients: croscarmellose sodium, magnesium stearate, and microcrystalline cellulose. The tablets are film-coated with a coating material containing indigo carmine aluminum lake, polyethylene glycol, polyvinyl alcohol, talc, and titanium dioxide.
Emtricitabine: The chemical name of FTC is 4-amino-5-fluoro-1-(2R-hydroxymethyl-1,3-oxathiolan-5S-yl)-(1H)-pyrimidin-2-one. FTC 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.
FTC has a molecular formula of C8H10FN3O3S and a molecular weight of 247.24 and has the following structural formula:
FTC is a white to off-white powder with a solubility of approximately 112 mg per mL in water at 25 °C.
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 an empirical formula of C21H29O5N6P∙½(C4H4O4) and a formula weight of 534.50 and has the following structural formula:
Tenofovir alafenamide fumarate is a white to off-white or tan powder with a solubility of 4.7 mg per mL in water at 20 °C.
Descovy - Clinical Pharmacology
Mechanism of Action
Descovy is a fixed dose combination of antiretroviral drugs emtricitabine (FTC) and tenofovir alafenamide (TAF) [see Microbiology (12.4)].
In a thorough QT/QTc study in 48 healthy subjects, TAF 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. The effect of the other component of Descovy, FTC, or the combination of FTC and TAF on the QT interval is not known.
Absorption, Distribution, Metabolism, and Excretion
The pharmacokinetic (PK) properties of the components of Descovy are provided in Table 2. The multiple dose PK parameters of FTC and TAF and its metabolite tenofovir are provided in Table 3.
|PBMCs=peripheral blood mononuclear cells; CES1=carboxylesterase 1|
|Effect of high fat meal (relative to fasting)*||AUC Ratio = 0.91 (0.89, 0.93)
Cmax Ratio = 0.74 (0.69, 0.78)
|AUC Ratio = 1.75 (1.64, 1.88)
Cmax Ratio= 0.85 (0.75, 0.95)
|% Bound to human plasma proteins||<4||~80|
|Source of protein binding data||In vitro||Ex vivo|
|Metabolism||Not significantly metabolized||Cathepsin A† (PBMCs)
|Major route of elimination||Glomerular filtration and active tubular secretion||Metabolism (>80% of oral dose)|
|% Of dose excreted in urine§||70||<1|
|% Of dose excreted in feces§||13.7||31.7|
|CV=Coefficient of Variation; NA=Not Applicable|
(microgram per mL)
|2.1 (20.2)||0.16 (51.1)||0.02 (26.1)|
(microgram∙hour per mL)
|11.7 (16.6)||0.21 (71.8)||0.29 (27.4)|
(microgram per mL)
|0.10 (46.7)||NA||0.01 (28.5)|
Patients with Renal Impairment
The pharmacokinetics of FTC+TAF combined with EVG+COBI in HIV infected subjects with renal impairment (eGFR 30 to 69 mL per minute by Cockcroft-Gault method) were evaluated in a subset of virologically-suppressed subjects in an open-label trial (Table 4).
|AUCtau (microgram∙hour per mL)
|Creatinine Clearance||≥90 mL per minute (N=18)†||60–89 mL per minute (N=11)‡||30–59 mL per minute (N=18)|
|Emtricitabine||11.4 (11.9)||17.6 (18.2)||23.0 (23.6)|
|Tenofovir Alafenamide§||0.23 (47.2)||0.24 (45.6)||0.26 (58.8)|
|Tenofovir||0.32 (14.9)||0.46 (31.5)||0.61 (28.4)|
Patients with Hepatic Impairment
Emtricitabine: The pharmacokinetics of FTC has not been studied in subjects with hepatic impairment; however, FTC is not significantly metabolized by liver enzymes, so the impact of hepatic impairment should be limited.
Tenofovir Alafenamide: Clinically relevant changes in tenofovir pharmacokinetics in subjects with hepatic impairment were not observed in subjects with mild to moderate (Child-Pugh Class A and B) hepatic impairment [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 subjects coinfected with hepatitis B and/or C virus.
Exposures of FTC and TAF in 24 pediatric subjects aged 12 to less than 18 years who received FTC+TAF and EVG+COBI were decreased (23% for AUC) compared to exposures achieved in treatment-naïve adults following administration of this dosage regimen [see Use in Specific Populations (8.4)]. These exposure differences are not thought to be clinically significant based on exposure-response relationships.
Pharmacokinetics of FTC and TAF have not been fully evaluated in the elderly (65 years of age and older). Population pharmacokinetics analysis of HIV-infected subjects in Phase 2 and Phase 3 trials of FTC+TAF and EVG+COBI showed that age did not have a clinically relevant effect on exposures of TAF up to 75 years of age [see Use in Specific Populations (8.5)].
Based on population pharmacokinetic analyses, no dosage adjustment is recommended based on race.
Based on population pharmacokinetic analyses, no dosage adjustment is recommended based on gender.
Drug Interaction Studies
The effects of coadministered drugs on the exposure of TAF are shown in Table 5 and the effects of Descovy or its components on the exposure of coadministered drugs are shown in Table 6 [these studies were conducted with Descovy or the components of Descovy (FTC or TAF) administered alone]. For information regarding clinical recommendations, see Drug Interactions (7).
|Coadministered Drug||Coadministered Drug(s) Dosage (once daily)
|Tenofovir Alafenamide Dosage (once daily)
|N||Mean Ratio of TAF PK Parameters (90% CI);
No effect = 1.00
|Atazanavir||300 (+100 ritonavir)||10||10||1.77
|Darunavir||800 (+150 cobicistat)||25†||11||0.93
|Darunavir||800 (+100 ritonavir)||10||10||1.42
|Lopinavir||800 (+200 ritonavir)||10||10||2.19
|Sertraline||50 (dosed as a single dose)||10 ‡||19||1.00
|Coadministered Drug||Coadministered Drug Dosage (once daily)
|Tenofovir Alafenamide Dosage (once daily)
|N||Mean Ratio of Coadministered Drug PK Parameters (90% CI);
No effect = 1.00
|Atazanavir||300 +100 ritonavir||10||10||0.98
|Darunavir||800 +150 cobicistat||25†||11||1.02
|Darunavir||800 +100 ritonavir||10||10||0.99
|Lopinavir||800 +200 ritonavir||10||10||1.00
|Sertraline||50 (dosed as a single dose)||10§||19||1.14
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 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, Ɛ, and mitochondrial DNA polymerase γ.
Tenofovir Alafenamide: TAF is a phosphonoamidate 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 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 in cell culture.
Antiviral Activity in Cell Culture
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. The EC50 values for FTC were in the range of 0.0013–0.64 micromolar. FTC displayed antiviral activity in cell culture against HIV-1 clades A, B, C, D, E, F, and G (EC50 values ranged from 0.007–0.075 micromolar) and showed strain specific activity against HIV-2 (EC50 values ranged from 0.007–1.5 micromolar).
In a study of FTC with a broad panel of representatives from the major classes of approved anti-HIV agents (NRTIs, non-nucleoside reverse transcriptase inhibitors [NNRTIs], integrase strand transfer inhibitors [INSTIs], and PIs) no antagonism was observed for these combinations.
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).
In a study of TAF with a broad panel of representatives from the major classes of approved anti-HIV agents (NRTIs, NNRTIs, INSTIs, and PIs) no antagonism was observed for these combinations.
In Cell Culture
Emtricitabine: HIV-1 isolates with reduced susceptibility to FTC were selected in cell culture and in subjects treated with FTC. Reduced susceptibility to FTC was associated with M184V or I substitutions in HIV-1 RT.
Tenofovir Alafenamide: HIV-1 isolates with reduced susceptibility to TAF were selected in cell culture. HIV-1 isolates selected by TAF expressed a K65R substitution in HIV-1 RT, sometimes in the presence of S68N or L429I substitutions; in addition, a K70E substitution in HIV-1 RT was observed.
In Clinical Trials
The resistance profile of Descovy in combination with other antiretroviral agents for the treatment of HIV-1 infection is based on studies of FTC+TAF with EVG+COBI in the treatment of HIV-1 infection. In a pooled analysis of antiretroviral-naïve subjects, genotyping was performed on plasma HIV-1 isolates from all subjects 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 subjects. The resistance-associated substitutions that emerged were M184V/I (N=7) and K65R (N=1). Three subjects had virus with emergent R, H, or E at the polymorphic Q207 residue in reverse transcriptase.
One subject was identified with emergent resistance to FTC or TAF (M184M/I) out of 4 virologic failure subjects in a clinical study of virologically-suppressed subjects who switched from a regimen containing FTC+TDF to FTC+TAF with EVG+COBI (N=799).
Emtricitabine: FTC-resistant viruses with the M184V or 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.
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.
Carcinogenesis, Mutagenesis, Impairment of Fertility
In long-term carcinogenicity studies of FTC, no drug-related increases in tumor incidence were found in mice at doses up to 750 mg per kg per day (23 times the human systemic exposure at the recommended dose of 200 mg per day in Descovy) or in rats at doses up to 600 mg per kg per day (28 times the human systemic exposure at the recommended dose in Descovy).
FTC was not genotoxic in the reverse mutation bacterial test (Ames test), mouse lymphoma or mouse micronucleus assays.
FTC did not affect fertility in male rats at approximately 140 times or in male and female mice at approximately 60 times higher exposures (AUC) than in humans given the recommended 200 mg daily dosage in Descovy. Fertility was normal in the offspring of mice exposed daily from before birth (in utero) through sexual maturity at daily exposures (AUC) of approximately 60 times higher than human exposures at the recommended 200 mg daily dosage in Descovy.
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 recommended dose of TDF (300 mg) 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 Descovy. At the high dose in female mice, liver adenomas were increased at tenofovir exposures approximately 10 times (300 mg TDF) and 167 times (Descovy) 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 62 times (25 mg TAF) 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.
Animal Toxicology and/or Pharmacology
Minimal to slight infiltration of mononuclear cells in the posterior uvea was observed in dogs with similar severity after three and nine month administration of TAF; reversibility was seen after a three month recovery period. No eye toxicity was observed in the dog at systemic exposures of 5 (TAF) and 15 (tenofovir) times the exposure seen in humans with the recommended daily TAF dose in Descovy.
In trials of FTC+TAF with EVG+COBI in HIV-1 infected adults as initial therapy in those with no antiretroviral treatment history (N=866) and to replace a stable antiretroviral regimen in those who were virologically-suppressed for at least 6 months with no known resistance substitutions (N=799), 92% and 96% of patients in the two populations, respectively, had HIV-1 RNA less than 50 copies per mL at Week 48.
In a trial of FTC+TAF with EVG+COBI in 23 treatment-naïve HIV-1 infected pediatric patients aged 12 to less than 18 years old and weighing greater than 35 kg, the virologic response rate (i.e., HIV-1 RNA less than 50 copies per mL) was 91% at 24 weeks.
In a trial in 248 HIV-1 infected adult patients with estimated creatinine clearance greater than 30 mL per minute but less than 70 mL per minute, 95% (235/248) of the combined population of treatment-naïve subjects (N=6) began on FTC+TAF with EVG+COBI and those previously virologically-suppressed on other regimens (N=242) and switched to FTC+TAF with EVG+COBI had HIV-1 RNA less than 50 copies per mL at Week 24.
How Supplied/Storage and Handling
Descovy 200 mg/25 mg tablets are blue, rectangular-shaped, and film-coated with "GSI" debossed on one side and "225" on the other side. Each bottle contains 30 tablets (NDC 61958-2002-1), a silica gel desiccant, polyester coil, and is closed with a child-resistant closure.
Store below 30 °C (86 °F).
- Keep container tightly closed.
- Dispense only in original container.
Patient Counseling Information
Advise the patient to read the FDA-approved patient labeling (Patient Information).
Post-treatment Acute Exacerbation of Hepatitis B in Patients with HBV Coinfection
Severe acute exacerbations of hepatitis B have been reported in patients who are coinfected with HBV and HIV-1 and have discontinued products containing FTC and/or TDF, and may likewise occur with discontinuation of Descovy [see Warnings and Precautions (5.1)]. Advise the patient to not discontinue Descovy without first informing their healthcare provider.
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 (5.2)].
New Onset or Worsening Renal Impairment
Advise patients to avoid taking Descovy 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 (5.3)].
Lactic Acidosis and Severe Hepatomegaly
Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with use of drugs similar to Descovy. Advise patients that they should stop Descovy if they develop clinical symptoms suggestive of lactic acidosis or pronounced hepatotoxicity [see Warnings and Precautions (5.4)].
Decrease in Bone Mineral Density
Advise patients that decreases in bone mineral density have been observed with the use of Descovy. Assessment of bone mineral density (BMD) should be considered in patients who have a history of pathologic bone fracture or other risk factors for osteoporosis or bone loss [see Warnings and Precautions (5.5)].
Inform patients that it is important to take Descovy on a regular dosing schedule with or without food and to avoid missing doses as it can result in development of resistance [see Dosage and Administration (2.2)].
Inform patients that there is an antiretroviral pregnancy registry to monitor fetal outcomes of pregnant women exposed to Descovy [see Use in Specific Populations (8.1)].
Instruct women 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)].
Descovy is a trademark of Gilead Sciences, Inc., or its related companies. All other trademarks referenced herein are the property of their respective owners.
© 2017 Gilead Sciences, Inc. All rights reserved.
and tenofovir alafenamide)
|This Patient Information has been approved by the U.S. Food and Drug Administration||Revised: 04/2017|
|Important: Ask your healthcare provider or pharmacist about medicines that should not be taken with Descovy. For more information, see the section "What should I tell my healthcare provider before taking Descovy?"|
|Read this Patient Information before you start taking Descovy and each time you get a refill. There may be new information. This information does not take the place of talking with your healthcare provider about your medical condition or treatment.|
|Descovy can cause serious side effects, including:|
|For more information about side effects, see the section "What are the possible side effects of Descovy?"|
|What is Descovy?|
|Descovy is a prescription medicine that is used together with other antiretroviral medicines to treat Human Immunodeficiency Virus-1 (HIV-1) in people 12 years of age and older.|
|HIV-1 is the virus that causes AIDS (Acquired Immune Deficiency Syndrome).|
|Descovy is not for use to help reduce the risk of getting HIV-1 infection by sexual contact in adults at high risk.|
|Descovy contains the prescription medicines emtricitabine (EMTRIVA®) and tenofovir alafenamide.|
|It is not known if Descovy is safe and effective in children under 12 years of age or who weigh less than 77 lb.|
|Descovy when used together with other HIV-1 medicines to treat HIV-1 infection may help:
|Reducing the amount of HIV-1 and increasing the CD4+ (T) cells in your blood may help improve your immune system. This may reduce your risk of death or getting infections that can happen when your immune system is weak (opportunistic infections).|
|Descovy does not cure HIV-1 infections or AIDS. You must keep taking HIV-1 medicines to control HIV-1 infection and decrease HIV-related illnesses.|
|Avoid doing things that can spread HIV-1 infection to others.
|Ask your healthcare provider if you have any questions about how to prevent passing HIV-1 to other people.|
|Before taking Descovy, tell your healthcare provider if you:
|Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.|
|Some medicines may interact with Descovy. Keep a list of your medicines and show it to your healthcare provider and pharmacist when you get a new medicine.
|How should I take Descovy?
|Descovy may cause serious side effects, including:
|The most common side effect of Descovy is nausea.|
|Tell your healthcare provider if you have any side effect that bothers you or that does not go away.|
|These are not all the possible side effects of Descovy. For more information, ask your healthcare provider or pharmacist.|
|Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.|
|How should I store Descovy?
|Keep Descovy and all medicines out of reach of children.|
|General information about the safe and effective use of Descovy.|
|Medicines are sometimes prescribed for purposes other than those listed in a Patient Information leaflet. Do not use Descovy for a condition for which it was not prescribed. Do not give Descovy to other people, even if they have the same symptoms you have. It may harm them.|
|If you would like more information, talk with your healthcare provider. You can ask your healthcare provider or pharmacist for information about Descovy that is written for health professionals.|
|For more information, call 1-800-445-3235 or go to www.Descovy.com.|
|What are the ingredients in Descovy?|
|Active ingredients: emtricitabine and tenofovir alafenamide.|
|Inactive ingredients: croscarmellose sodium, magnesium stearate, and microcrystalline cellulose.|
|The tablets are film-coated with a coating material containing indigo carmine aluminum lake, polyethylene glycol, polyvinyl alcohol, talc, and titanium dioxide.|
|Manufactured and distributed by: Gilead Sciences, Inc. Foster City, CA 94404|
|Descovy is a trademark of Gilead Sciences, Inc., or its related companies. All other trademarks referenced herein are the property of their respective owners.|
|© 2017 Gilead Sciences, Inc. All rights reserved.
PRINCIPAL DISPLAY PANEL - 200 mg/25 mg Tablet Bottle Label
(emtricitabine and tenofovir
200 mg/25 mg
Note to pharmacist: Do not cover ALERT box with pharmacy label.
ALERT: Find out about medicines that
should NOT be taken with Discovy®
emtricitabine and tenofovir alafenamide tablet
|Labeler - Gilead Sciences, Inc. (185049848)|
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- Drug class: antiviral combinations