Emtricitabine and Tenofovir Disoproxil Fumarate (Page 3 of 11)

5.5 Bone Loss and Mineralization Defects

Bone Mineral Density

In clinical trials in HIV-1 infected adults and in a clinical trial of HIV-1 uninfected individuals, TDF (a component of Emtricitabine and Tenofovir disoproxil fumarate tablets) was associated with slightly greater decreases in bone mineral density (BMD) and increases in biochemical markers of bone metabolism, suggesting increased bone turnover relative to comparators [see Adverse Reactions (6.1)]. Serum parathyroid hormone levels and 1,25 Vitamin D levels were also higher in subjects receiving TDF.

Clinical trials evaluating TDF in pediatric and adolescent subjects were conducted. Under normal circumstances, BMD increases rapidly in pediatric patients. In HIV-1 infected subjects aged 2 years to less than 18 years, bone effects were similar to those observed in adult subjects and suggest increased bone turnover. Total body BMD gain was less in the TDF-treated HIV-1 infected pediatric subjects as compared to the control groups. Similar trends were observed in adolescent subjects aged 12 years to less than 18 years treated for chronic hepatitis B. In all pediatric trials, skeletal growth (height) appeared to be unaffected.

The effects of TDF-associated changes in BMD and biochemical markers on long-term bone health and future fracture risk are unknown. Assessment of BMD should be considered for adult and pediatric patients who have a history of pathologic bone fracture or other risk factors for osteoporosis or bone loss. Although the effect of supplementation with calcium and vitamin D was not studied, such supplementation may be beneficial. If bone abnormalities are suspected, appropriate consultation should be obtained.

Mineralization Defects

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 TDF use [see Adverse Reactions (6.1)]. Arthralgia and muscle pain or weakness have also been reported in cases of proximal renal tubulopathy. Hypophosphatemia and osteomalacia secondary to proximal renal tubulopathy should be considered in patients at risk of renal dysfunction who present with persistent or worsening bone or muscle symptoms while receiving TDF-containing products [see Warnings and Precautions (5.3)].

5.6 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 FTC and TDF, components of Emtricitabine and Tenofovir disoproxil fumarate tablets, alone or in combination with other antiretrovirals. Treatment with Emtricitabine and Tenofovir disoproxil fumarate tablets should be suspended in any individual 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).

5.7 Risk of Adverse Reactions Due to Drug Interactions

The concomitant use of Emtricitabine and Tenofovir disoproxil fumarate tablets and other drugs may result in known or potentially significant drug interactions, some of which may lead to possible clinically significant adverse reactions from greater exposures of concomitant drugs [see Drug Interactions (7.2)].

See Table 7 for steps to prevent or manage these possible and known significant drug interactions, including dosing recommendations. Consider the potential for drug interactions prior to and during therapy with Emtricitabine and Tenofovir disoproxil fumarate tablets; review concomitant medications during therapy with Emtricitabine and Tenofovir disoproxil fumarate tablets; and monitor for adverse reactions associated with the concomitant drugs.

6 ADVERSE REACTIONS

The following adverse reactions are discussed in other sections of the labeling:

  • Severe Acute Exacerbations of Hepatitis B in Patients with HBV Infection [see Warnings and Precautions (5.1)].
  • New Onset or Worsening Renal Impairment [see Warnings and Precautions (5.3)].
  • Immune Reconstitution Syndrome [see Warnings and Precautions (5.4)].
  • Bone Loss and Mineralization Defects [see Warnings and Precautions (5.5)].
  • Lactic Acidosis/Severe Hepatomegaly with Steatosis [see Warnings and Precautions (5.6)].

6.1 Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Adverse Reactions from Clinical Trials Experience in HIV-1 Infected Subjects

Clinical Trials in Adult Subjects

In Study 934, 511 antiretroviral-naïve subjects received efavirenz (EFV) administered in combination with either FTC+TDF (N=257) or zidovudine (AZT)/lamivudine (3TC) (N=254) for 144 weeks. The most common adverse reactions (incidence greater than or equal to 10%, all grades) included diarrhea, nausea, fatigue, headache, dizziness, depression, insomnia, abnormal dreams, and rash. Table 3 provides the treatment-emergent adverse reactions (Grades 2–4) occurring in greater than or equal to 5% of subjects treated in any treatment group.

Skin discoloration, manifested by hyperpigmentation, occurred in 3% of subjects taking FTC+TDF, and was generally mild and asymptomatic. The mechanism and clinical significance are unknown.

Table 3 Selected Adverse Reactions a (Grades 2–4) Reported in ≥5% in Any Treatment Group in Study 934 (0–144 Weeks)
FTC+TDF+EFV b AZT/3TC+EFV
N=257 N=254
Fatigue 9% 8%
Depression 9% 7%
Nausea 9% 7%
Diarrhea 9% 5%
Dizziness 8% 7%
Upper respiratory tract infections 8% 5%
Sinusitis 8% 4%
Rash event c 7% 9%
Headache 6% 5%
Insomnia 5% 7%
Nasopharyngitis 5% 3%
Vomiting 2% 5%
a. Frequencies of adverse reactions are based on all treatment- emergent adverse events, regardless of relationship to study drug. b. From Weeks 96 to 144 of the trial, subjects received Emtricitabine and Tenofovir disoproxil fumarate tablets with efavirenz in place of FTC+TDF with efavirenz. c. Rash event includes rash, exfoliative rash, rash generalized, rash macular, rash maculo- papular, rash pruritic, and rash vesicular.

Laboratory Abnormalities: Laboratory abnormalities observed in this trial were generally consistent with those seen in other trials of TDF and/or FTC (Table 4).

Table 4 Significant Laboratory Abnormalities Reported in ≥1% of Subjects in Any Treatment Group in Study 934 (0–144 Weeks)
FTC+TDF+EFV a AZT/3TC+EFV
N=257 N=254
Any ≥ Grade 3 Laboratory Abnormality 30% 26%
Fasting Cholesterol (>240 mg/dL) 22% 24%
Creatine Kinase (M: >990 U/L) (F: >845 U/L) 9% 7%
Serum Amylase (>175 U/L) 8% 4%
Alkaline Phosphatase (>550 U/L) 1% 0%
AST (M: >180 U/L) (F: >170 U/L) 3% 3%
ALT (M: >215 U/L) (F: >170 U/L) 2% 3%
Hemoglobin (<8.0 mg/dL) 0% 4%
Hyperglycemia (>250 mg/dL) 2% 1%
Hematuria (>75 RBC/HPF) 3% 2%
Glycosuria (≥3+) <1% 1%
Neutrophils (<750/mm3) 3% 5%
Fasting Triglycerides (>750 mg/dL) 4% 2%
a From Weeks 96 to 144 of the trial, subjects received Emtricitabine and Tenofovir disoproxil fumarate tablets with efavirenz in place of FTC+TDF with efavirenz.

Clinical Trials in Pediatric Subjects

Emtricitabine: In addition to the adverse reactions reported in adults, anemia and hyperpigmentation were observed in 7% and 32%, respectively, of pediatric subjects (3 months to less than 18 years of age) who received treatment with FTC in the larger of two open-label, uncontrolled pediatric trials (N=116).

Tenofovir Disoproxil Fumarate: In pediatric clinical trials (Studies 352 and 321) conducted in 184 HIV-1 infected subjects 2 to less than 18 years of age, the adverse reactions observed in pediatric subjects who received treatment with TDF were consistent with those observed in clinical trials of TDF in adults.

In Study 352 (2 to less than 12 years of age), 89 pediatric subjects received TDF for a median exposure of 104 weeks. Of these, 4 subjects discontinued from the trial due to adverse reactions consistent with proximal renal tubulopathy. Three of these 4 subjects presented with hypophosphatemia and had decreases in total body or spine BMD Z-score [see Warnings and Precautions (5.5)]. Total body BMD gain at Week 48 was less in the TDF group compared to the stavudine (d4T) or zidovudine (AZT) treatment groups. The mean rate of BMD gain in lumbar spine was similar between treatment groups. One TDF-treated subject and none of the d4T- or AZT-treated subjects experienced significant (greater than 4%) lumbar spine BMD loss at Week 48. Changes from baseline in BMD Z-scores were −0.012 for lumbar spine and −0.338 for total body in the 64 subjects who were treated with TDF for 96 weeks.

In Study 321 (12 to less than 18 years of age), the mean rate of BMD gain at Week 48 was less in the TDF compared to the placebo treatment group. Six TDF-treated subjects and one placebo-treated subject had significant (greater than 4%) lumbar spine BMD loss at Week 48. Changes from baseline BMD Z-scores were −0.341 for lumbar spine and −0.458 for total body in the 28 subjects who were treated with TDF for 96 weeks.

In both trials, skeletal growth (height) appeared to be unaffected.

Adverse Reactions from Clinical Trial Experience in Uninfected Subjects Taking Emtricitabine and Tenofovir disoproxil fumarate tablets for HIV- 1 PrEP

Clinical Trials in Adult Subjects

The safety profile of Emtricitabine and Tenofovir disoproxil fumarate tablets for HIV-1 PrEP was comparable to that observed in clinical trials of HIV-infected subjects based on two randomized placebo-controlled clinical trials (iPrEx, Partners PrEP) in which 2,830 HIV-1 uninfected adults received Emtricitabine and Tenofovir disoproxil fumarate tablets once daily for HIV-1 PrEP. Subjects were followed for a median of 71 weeks and 87 weeks, respectively. Table 5 provides a list of selected adverse events that occurred in 2% or more of subjects in any treatment group in the iPrEx trial, with an incidence greater than placebo.

Table 5 Selected Adverse Events (All Grades) Reported in ≥2% in Any Treatment Group in the iPrEx Trial and Greater than Placebo
FTC/TDF (N=1251) Placebo (N=1248)
Headache 7% 6%
Abdominal pain 4% 2%
Weight decreased 3% 2%

In the Partners PrEP trial, the frequency of adverse events in the Emtricitabine and Tenofovir disoproxil fumarate tablets treatment group was generally either less than or the same as in the placebo group.

Laboratory Abnormalities: Table 6 provides a list of Grade 2–4 laboratory abnormalities observed in the iPrEx and Partners PrEP trials. Six subjects in the TDF-containing arms of the Partners PrEP trial discontinued from the trial due to an increase in serum creatinine compared with no discontinuations in the placebo group. One subject in the Emtricitabine and Tenofovir disoproxil fumarate tablets arm of the iPrEx trial discontinued from the trial due to an increase in serum creatinine and another subject discontinued due to low serum phosphorus. Grades 2−3 proteinuria (2–4+) and/or glycosuria (3+) occurred in less than 1% of subjects treated with Emtricitabine and Tenofovir disoproxil fumarate tablets in the iPrEx trial and Partners PrEP trial.

Table 6 Laboratory Abnormalities (Highest Toxicity Grade Reported for Each Subject) in the iPrEx Trial and Partners PrEP Trial
Grade 2–4 a iPrEx Trial Partners PrEP Trial
FTC/TDF (N=1251) Placebo (N=1248) FTC/TDF (N=1579) Placebo (N=1584)
Creatinine (>1.4 × ULN) <1% <1% <1% <1%
Phosphorus (<2.0 mg/dL) 10% 8% 9% 9%
AST (>2.6 × ULN) 5% 5% <1% <1%
ALT (>2.6 × ULN) 7% 7% <1% <1%
Hemoglobin (<9.4 mg/dL) 1% 2% 2% 2%
Neutrophils (<750/mm3) <1% <1% 5% 3%
a Grading is per DAIDS criteria.

Changes in Bone Mineral Density: In clinical trials of HIV-1 uninfected individuals, decreases in BMD were observed. In the iPrEx trial, a substudy of 503 subjects found mean changes from baseline in BMD ranging from –0.4% to –1.0% across total hip, spine, femoral neck, and trochanter in the Emtricitabine and Tenofovir disoproxil fumarate tablets group compared with the placebo group, which returned toward baseline after discontinuation of treatment. Thirteen percent of Emtricitabine and Tenofovir disoproxil fumarate tablets -treated subjects versus 6% of placebo-treated subjects lost at least 5% of BMD at the spine during treatment. Bone fractures were reported in 1.7% of the Emtricitabine and Tenofovir disoproxil fumarate tablets group compared with 1.4% in the placebo group. No correlation between BMD and fractures was noted [see Clinical Studies (14.3)]. The Partners PrEP trial found similar fracture rates between the treatment and placebo groups (0.8% and 0.6%, respectively); no BMD evaluations were performed in this trial [see Clinical Studies (14.4)].

Clinical Trials in Adolescent Subjects

In a single-arm, open-label clinical trial (ATN113), in which 67 HIV-1 uninfected adolescent (15 to 18 years of age) men who have sex with men received Emtricitabine and Tenofovir disoproxil fumarate tablets once daily for HIV-1 PrEP, the safety profile of Emtricitabine and Tenofovir disoproxil fumarate tablets was similar to that observed in adults. Median duration to exposure of Emtricitabine and Tenofovir disoproxil fumarate tablets was 47 weeks [see Use in Specific Populations (8.4)].

In the ATN113 trial, median BMD increased from baseline to Week 48, +2.58% for lumbar spine and +0.72% for total body. One subject had significant (greater than or equal to 4%) total body BMD loss at Week 24. Median changes from baseline BMD Z-scores were 0.0 for lumbar spine and −0.2 for total body at Week 48. Three subjects showed a worsening (change from > −2 to ≤ −2) from baseline in their lumbar spine or total body BMD Z-scores at Week 24 or 48. Interpretation of these data, however, may be limited by the low rate of adherence to Emtricitabine and Tenofovir disoproxil fumarate tablets by Week 48.

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