Tafnext Special Precautions

Severe Acute Exacerbation of Hepatitis B after Discontinuation of Treatment: Discontinuation of anti-hepatitis B therapy, including Tenofovir Alafenamide, may result in severe acute exacerbations of hepatitis B. Patients who discontinue Tenofovir Alafenamide should be closely monitored with both clinical and laboratory follow-up for at least several months after stopping treatment. If appropriate, resumption of anti-hepatitis B therapy may be warranted.
Risk of Development of HIV-1 Resistance in Patients Coinfected with HBV and HIV-1: Due to the risk of development of HIV-1 resistance, Tenofovir Alafenamide alone is not recommended for the treatment of HIV-1 infection. The safety and efficacy of Tenofovir Alafenamide have not been established in patients coinfected with HBV and HIV-1. HIV antibody testing should be offered to all HBV-infected patients before initiating therapy with Tenofovir Alafenamide, and, if positive, an appropriate antiretroviral combination regimen that is recommended for patients coinfected with HIV-1 should be used.
New Onset or Worsening Renal Impairment: Post marketing cases of renal impairment, including acute renal failure, proximal renal tubulopathy (PRT), and Fanconi syndrome have been reported with TAF-containing products; while most of these cases were characterized by potential confounders that may have contributed to the reported renal events, it is also possible these factors may have predisposed patients to tenofovir-related adverse events (see Adverse Reactions).
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 (see Interactions).
Prior to or when initiating Tenofovir Alafenamide, and during treatment with Tenofovir Alafenamide on a clinically appropriate schedule, assess serum creatinine, estimated creatinine clearance, urine glucose, and urine protein in all patients. In patients with chronic kidney disease, also assess serum phosphorus. Discontinue Tenofovir Alafenamide in patients who develop clinically significant decreases in renal function or evidence of Fanconi syndrome (see Adverse Reactions and Renal impairment as follows).
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 tenofovir disoproxil fumarate (TDF), another prodrug of tenofovir, alone or in combination with other antiretrovirals. Treatment with Tenofovir Alafenamide 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).
Renal Impairment: No dosage adjustment of Tenofovir Alafenamide is required in patients with mild, moderate, or severe renal impairment, or in patients with ESRD (estimated creatinine clearance below 15 mL per minute) who are receiving chronic hemodialysis. On days of hemodialysis, administer Tenofovir Alafenamide after completion of hemodialysis treatment (see Dosage & Administration).
The safety and efficacy of Tenofovir Alafenamide in HBV-infected adult subjects with moderate to severe renal impairment (estimated creatinine clearance between 15 and 59 mL per minute by Cockcroft-Gault method) and ESRD (estimated creatinine clearance of less than 15 mL per minute by Cockcroft-Gault method) receiving chronic hemodialysis were evaluated in 78 and 15 subjects, respectively, in an open-label trial (Trial 4035, Part A). Overall, 98% of subjects achieved HBV DNA <20 IU/mL at Week 24 (Cohort 1, 97%; Cohort 2, 100%) and the safety of Tenofovir Alafenamide was similar to that observed in clinical trials of Tenofovir Alafenamide in subjects with compensated liver disease but without renal impairment (see Adverse Reactions).
The safety and efficacy of elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide 150/150/200/10 mg was previously evaluated in 55 virologically suppressed HIV-1 infected subjects with ESRD receiving chronic hemodialysis in an open-label study (Trial 1825). Tenofovir alafenamide exposures are similar when comparing tenofovir alafenamide 25 mg and tenofovir alafenamide 10 mg as part of elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide.
Among subjects with ESRD receiving chronic hemodialysis and administered tenofovir alafenamide, higher exposures of tenofovir were observed in HBV-infected subjects (Trial 4035 Part A) compared to HIV-infected subjects (Trial 1825). The clinical significance of these higher exposures is not established (see Pharmacology under Actions).
Tenofovir Alafenamide is not recommended in patients with ESRD (estimated creatinine clearance below 15 mL per minute by Cockcroft-Gault method) who are not receiving chronic hemodialysis as the safety of Tenofovir Alafenamide has not been established in this population (see Dosage & Administration and Pharmacology under Actions).
Hepatic Impairment: No dosage adjustment of Tenofovir Alafenamide is required in patients with mild hepatic impairment (Child-Pugh A). The safety and efficacy of Tenofovir Alafenamide in patients with decompensated cirrhosis (Child-Pugh B or C) have not been established; therefore, Tenofovir Alafenamide is not recommended in patients with decompensated (Child- Pugh B or C) hepatic impairment (see Dosage & Administration and Pharmacology under Actions).
Use in Children: Safety and effectiveness of Tenofovir Alafenamide in pediatric patients less than 18 years of age have not been established.
Use in the Elderly: In clinical trials, Tenofovir Alafenamide was administered to 89 subjects aged 65 and over. No clinically significant differences in safety or efficacy have been observed between elderly subjects and subjects between 18 and less than 65 years of age.