New article: BJCP - Plasma bictegravir/emtricitabine/tenofovir alafenamide concentrations in transgender women with HIV on oestrogen-based gender-affirming hormone therapy in comparison to cisgender women living with HIV
Background:
Oestrogen-based gender-affirming hormone therapy (E-GAHT), which includes oestrogen with or without anti-androgens, is vital for many transgender women. However, there are concerns about possible drug–drug interactions between E-GAHT and antiretroviral therapy (ART). This study aimed to compare the pharmacokinetics of bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) in transgender women on E-GAHT versus cisgender women.
Methods:
A parallel-group study was conducted with adult transgender and cisgender women with HIV, all on suppressive ART. Transgender participants were on stable E-GAHT (≥2 mg/day estradiol plus anti-androgens) for at least 3 months. At Month 2, blood samples were collected at multiple timepoints post-dose to measure BIC, FTC, and TAF plasma levels using validated LC-MS/MS. Pharmacokinetic parameters (Cmax, Cmin, AUC) were calculated and compared between groups using geometric mean ratios (GMR) and 90% confidence intervals.
Results:
25 participants were enrolled (10 transgender, 15 cisgender). E-GAHT included estradiol (median 4 mg) and various anti-androgens. BIC pharmacokinetics (Cmax, Cmin, AUC) were similar between groups, with GMRs close to 1. FTC and TAF pharmacokinetics also showed no significant differences between transgender and cisgender women. All participants maintained viral suppression throughout the study.
Conclusion:
The pharmacokinetics of BIC/FTC/TAF were comparable between transgender women on E-GAHT and cisgender women, indicating no clinically relevant drug–drug interactions.
Additional information to the following link: Plasma bictegravir/emtricitabine/tenofovir alafenamide concentrations in transgender women with HIV on oestrogen‐based gender‐affirming hormone therapy in comparison to cisgender women living with HIV - Sunagawa - 2025 - British Journal of Clinical Pharmacology - Wiley Online Library