Role of plasmatic and urinary concentration of tenofovir disoproxil fumarate in a cohort of patients affected by chronic hepatitis B

The aim of this study was to evaluate plasmatic and urinary therapeutic drug monitoring (TDM) of tenofovir disoproxil fumarate (TDF) in a cohort of patients with chronic hepatitis B (CHB). In 68 enrolled patients, the estimated glomerular filtration rate (eGFR) was 68 mL/min in naive subjects, while in adefovir dipivoxil (ADV)-pretreated patients, it was 55.5 mL/min (p < 0.001). The HBV E genotype was associated with lower TDF levels (β = -0.698, p < 0.001). The urinary TDF concentration was associated with ADV pretreatment (β = 0.829, p < 0.001). Determination of urinary concentrations of TDF may be useful in the clinical management of older CHB patients and those with previous treatment with ADV.