Single-dose pharmacokinetics of tenofovir alafenamide and its active metabolite in the mucosal tissues. (24th March 2017)

• Record Type: Journal Article
• Authors: Cottrell, Mackenzie L.; Garrett, Katy L.; Prince, Heather M. A.; Sykes, Craig; Schauer, Amanda; Emerson, Cindi W.; Peery, Anne; Rooney, James F.; McCallister, Scott; Gay, Cynthia; Kashuba, Angela D. M.
• Is Part Of: Journal of antimicrobial chemotherapy. Volume 72:Number 6(2017:Jun.)
• Page Start: 1731
• Page End: 1740
• Publication Date: 2017-03-24
• Subjects: Anti-infective agents -- Periodicals; Chemotherapy -- Periodicals; 615.58
• DOI: 10.1093/jac/dkx064
• Languages: English
• ISSNs: 0305-7453

Abstract

Abstract: Objectives: Tenofovir alafenamide, a prodrug of tenofovir, produces higher PBMC concentrations of tenofovir diphosphate (tenofovir-dp) than tenofovir disoproxil fumarate. To understand tenofovir alafenamide's mucosal tissue distribution and its implications for pre-exposure prophylaxis, we characterized tenofovir-dp in female genital tract (FGT) and lower gastrointestinal (GI) tissues. Methods: Healthy seronegative women were given 5, 10 or 25 mg of tenofovir alafenamide ( n = 8/group). Each participant provided plasma, PBMC and cervical, vaginal and rectal tissue samples over 14 days. Plasma, cell lysate and tissue homogenate concentrations were analysed by LC-MS/MS. Dose proportionality was declared in plasma and PBMCs if the natural log AUC versus natural log dose regression line 90% CI was within 0.57–1.43. In vitro tenofovir-dp formation was assessed in PBMCs and ectocervical (Ect1/E6E7) and vaginal (VK2/E6E7) cells incubated in 0.5 and 10 μM tenofovir alafenamide or tenofovir. clinicaltrials.gov: NCT02357602. Results: Following single doses of 5, 10 and 25 mg, median (IQR) tenofovir plasma AUC0–14 days was 52.8 (49.5–59.6), 78.1 (68.2–86.9) and 169.7 (131.2–211.4) ng·h/mL and tenofovir-dp PBMC AUC0–14 days was 2268 (1519–4090), 4584 (3113–5734) and 9306 (6891–10785) fmol·h/10 6 cells, respectively. Tenofovir was quantifiable in 52% and 92% of FGT and GI tissues, whereas tenofovir-dp was quantifiable in only 5% and 19% of FGT and GI tissues, respectively. Plasma tenofovir and PBMC tenofovir-dp were dose proportional (90% CI = 0.87–1.15 and 0.62–1.02, respectively). In vitro tenofovir-dp was 1.7–17-fold higher in epithelial cells than PBMCs. Conclusions: After tenofovir alafenamide dosing in vivo, tenofovir-dp was unquantifiable in most tissues (91%) although cervical and vaginal epithelial cells efficiently formed tenofovir-dp from tenofovir alafenamide in vitro . These findings warrant further investigation of tenofovir alafenamide's pharmacology.