Short Communication: Association of Vitamin D Insufficiency and Protective Tenofovir Diphosphate Concentrations with Bone Toxicity in Adolescent Boys and Young Men Using Tenofovir Disoproxil Fumarate/Emtricitabine for HIV Pre-Exposure Prophylaxis

Abstract Background Transwomen have an increased risk of HIV acquisition compared with other adults. Drug–drug interactions between pre-exposure prophylaxis (PrEP) and gender-affirming therapy are cited as a reason for poor PrEP uptake among transwomen. We evaluated plasma tenofovir and emtricitabine pharmacokinetics and their active intracellular anabolites, tenofovir-diphosphate and emtricitabine-triphosphate, in transwomen receiving feminizing hormones. Methods We enrolled HIV-negative transwomen (≥19 years) not receiving PrEP. Participants took oral tenofovir disoproxil fumarate/emtricitabine 300/200 mg daily for 14 days. Plasma was collected at 0 h (pre-dose), 0.5, 1, 2, 3, 4, 6, 8 and 12 h on day 14 post-tenofovir disoproxil fumarate/emtricitabine dose. The plasma AUC0–24 was calculated using the trapezoidal rule and compared with historical HIV-negative cisgender adults as geometric mean ratios (GMRs, 90% CI). Secondarily, tenofovir-diphosphate and emtricitabine-triphosphate from PBMCs collected at 0 h and 12 h were reported descriptively as geometric means (90% CI). Clinical trials registration: NCT03270969. Results Among 15 transwomen (mean age 32 years), geometric mean tenofovir and emtricitabine plasma AUC0–24 were lower compared with controls: tenofovir, 2.10 versus 2.76 mg·h/L, GMR 0.76 (0.65–0.90), P = 0.01; emtricitabine, 9.15 versus 10.64 mg·h/L, GMR 0.86 (0.75–0.98), P = 0.07. Tenofovir-diphosphate and emtricitabine-triphosphate concentrations were higher than previously reported in the literature: 167.1 (146.6–190.5) fmol/106 cells and 15.4 (13.8–17.3) pmol/106 cells, respectively. Conclusions We observed lower plasma tenofovir and emtricitabine concentrations in transwomen compared with historical cisgender adults, yet intracellular tenofovir-diphosphate and emtricitabine-triphosphate concentrations were higher than previously reported in PBMCs. Understanding the differences of PrEP pharmacokinetics in plasma and tissue compartments and the resultant impact on efficacy remains important for transwomen.

Download Full-text

Effect of Vitamin D Supplementation on Bone Turnover Markers During HIV Pre-Exposure Prophylaxis Using Tenofovir Disoproxil Fumarate-Emtricitabine in Men Who Have Sex with Men

AIDS Research and Human Retroviruses ◽

10.1089/aid.2018.0280 ◽

2019 ◽

Vol 35 (7) ◽

pp. 608-614 ◽

Cited By ~ 2

Author(s):

Deepa D. Nanayakkara ◽

Xiaoying Sun ◽

Sheldon Morris ◽

Stan Louie ◽

Kathleen Mulligan ◽

...

Keyword(s):

Vitamin D ◽

Bone Turnover ◽

Tenofovir Disoproxil Fumarate ◽

Bone Turnover Markers ◽

Vitamin D Supplementation ◽

Turnover Markers ◽

Sex With Men ◽

Exposure Prophylaxis

Download Full-text

Association of Higher Plasma Vitamin D Binding Protein and Lower Free Calcitriol Levels with Tenofovir Disoproxil Fumarate Use and Plasma and Intracellular Tenofovir Pharmacokinetics: Cause of a Functional Vitamin D Deficiency?

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01096-13 ◽

2013 ◽

Vol 57 (11) ◽

pp. 5619-5628 ◽

Cited By ~ 40

Author(s):

Peter L. Havens ◽

Jennifer J. Kiser ◽

Charles B. Stephensen ◽

Rohan Hazra ◽

Patricia M. Flynn ◽

...

Keyword(s):

Vitamin D ◽

Parathyroid Hormone ◽

Vitamin D Deficiency ◽

Tenofovir Disoproxil Fumarate ◽

Binding Protein ◽

Tubular Reabsorption ◽

Plasma Vitamin ◽

Calcium Balance ◽

Vitamin D Binding Protein ◽

Tenofovir Diphosphate

ABSTRACTTenofovir disoproxil fumarate (TDF) causes bone, endocrine, and renal changes by an unknown mechanism(s). Data are limited on tenofovir pharmacokinetics and these effects. Using baseline data from a multicenter study of HIV-infected youth on stable treatment with regimens containing TDF (n= 118) or lacking TDF (n= 85), we measured cross-sectional associations of TDF use with markers of renal function, vitamin D-calcium-parathyroid hormone balance, phosphate metabolism (tubular reabsorption of phosphate and fibroblast growth factor 23 [FGF23]), and bone turnover. Pharmacokinetic-pharmacodynamic associations with plasma tenofovir and intracellular tenofovir diphosphate concentrations were explored among those receiving TDF. The mean age was 20.9 (standard deviation [SD], 2.0) years; 63% were male; and 52% were African American. Compared to the no-TDF group, the TDF group showed lower mean estimated glomerular filtration rates and tubular reabsorption of phosphate, as well as higher parathyroid hormone and 1,25-dihydroxy vitamin D [1,25-OH(2)D] levels. The highest quintile of plasma tenofovir concentrations was associated with higher vitamin D binding protein, lower free 1,25-OH(2)D, higher 25-OH vitamin D, and higher serum calcium. The highest quintile of intracellular tenofovir diphosphate concentration was associated with lower FGF23. Higher plasma tenofovir concentrations were associated with higher vitamin D binding protein and lower free 1,25-OH(2)D, suggesting a functional vitamin D deficiency explaining TDF-associated increased parathyroid hormone. The finding of lower FGF23 accompanying higher intracellular tenofovir diphosphate suggests that different mechanisms mediate TDF-associated changes in phosphate handling. Separate pharmacokinetic properties may be associated with distinct TDF toxicities: tenofovir with parathyroid hormone and altered calcium balance and tenofovir diphosphate with hypophosphatemia and FGF23 regulation.IMPORTANCE(The clinical trial registration number for this study is NCT00490412 and is available online athttp://clinicaltrials.gov/ct2/show/NCT00490412.)

Download Full-text