Steady-state pharmacokinetics of plasma tenofovir alafenamide (TAF), tenofovir (TFV) and emtricitabine (FTC), and intracellular TFV-diphosphate and FTC-triphosphate in HIV-1 infected old Japanese patients treated with bictegravir/FTC/TAF

Emtricitabine (FTC) plus tenofovir alafenamide (TAF) has demonstrated efficacy and safety for pre-exposure prophylaxis (PrEP) to prevent HIV-1 infection. We measured the plasma PK of FTC, (TFV), TAF in a steady-state pharmacokinetic (PK) study bictegravir/FTC/TAF HIV-1-infected patients. Furthermore, validated liquid chromatography-tandem mass spectrometry was used measure intracellular TFV-diphosphate (DP) FTC-triphosphate (TP), active metabolites TFV respectively. Plasma dried blood spot samples were collected from 10 male patients aged ≥ 50 years at various time intervals: 0 (trough), 1, 2, 3, 4, 6, 8, 12, 24 h after drug administration. The mean ± standard deviation parameters as follows: maximum concentrations TAF, TFV, FTC 104.0 72.5, 27.9 5.2, 3,976.0 683.6 ng/mL, Additionally, their terminal elimination half-lives 0.6 0.5, 31.6 10.4, 6.9 1.4 h, These results consistent with previously reported data. levels TFV-DP FTC-TP varied widely among individuals; however, they remained stable over each individual approximately 1,000–1,500 2,000–3,000 fmol/punch, respectively, indicating that did not affect metabolites. measuring could be useful monitoring adherence PrEP clients on this regimen.