Gender-Affirming Hormone Pharmacokinetics Among Adolescent and Young Adult Transgender Persons Receiving Daily Emtricitabine/Tenofovir Disoproxil Fumarate

Social, economic, and physical side effects impact PrEP uptake and persistence among transgender women in Peru

INTRODUCTION

Oral pre-exposure prophylaxis (PrEP) for HIV-1 infection is over 99% effective in protecting against HIV acquisition when used consistently and appropriately. However, PrEP uptake and persistent use remains suboptimal, with a substantial gap in utilization among key populations who could most benefit from PrEP. In Latin America specifically, there is poor understanding of barriers to PrEP uptake and persistence among transgender (trans) women.

METHODS

In April-May 2018, we conducted qualitative interviews lasting 25-45 min as part of an end-of-project evaluation of TransPrEP, a pilot RCT that examined the impact of a social network-based peer support intervention on PrEP adherence among trans women in Lima, Peru. Participants in the qualitative evaluation, all adult trans women, included individuals who either (1) screened eligible to participate in the TransPrEP pilot, but opted not to enroll (n = 8), (2) enrolled, but later withdrew (n = 6), (3) were still actively enrolled at the time of interview and/or successfully completed the study (n = 16), or (4) were study staff (n = 4). Interviews were audio recorded and transcribed verbatim. Codebook development followed an immersion/crystallization approach, and coding was completed using Dedoose.

RESULTS

Evaluation participants had a mean age of 28.2 years (range 19-47). When describing experiences taking PrEP, participant narratives highlighted side effects that spanned three domains: physical side effects, such as prolonged symptoms of gastrointestinal distress or somnolence; economic challenges, including lost income due to inability to work; and social concerns, including interpersonal conflicts due to HIV-related stigma. Participants described PrEP use within a broader context of social and economic marginalization, with a focus on daily survival, and how PrEP side effects negatively contributed to these stressors. Persistence was, in some cases, supported through the intervention's educational workshops.

CONCLUSION

This research highlights the ways that physical, economic, and social side effects of PrEP can impact acceptability and persistence among trans women in Peru, amplifying and layering onto existing stressors including economic precarity. Understanding the unique experiences of trans women taking PrEP is crucial to informing tailored interventions to improve uptake and persistence.

Drug-drug interactions between gender-affirming hormone therapy and antiretrovirals for treatment/prevention of HIV

Transgender persons face a greater burden of HIV compared to cisgender counterparts. Concerns around drug-drug interactions (DDIs) have been cited as reasons for lower engagement in HIV care and lower pre-exposure prophylaxis (PrEP) uptake among transgender populations. It is therefore imperative for hormone therapy, PrEP and antiretroviral therapy providers to understand the DDI potential between these therapies. Studies of tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC) PrEP with feminizing hormone therapies (FHTs) show reduced plasma tenofovir concentrations, but intracellular concentrations of tenofovir-diphosphate are not reduced. Efficacy of PrEP is expected to be maintained despite this interaction. Masculinizing hormone therapies have no effect on tenofovir concentrations but may increase FTC to a nonclinically relevant extent. No interactions between FHT and cabotegravir or tenofovir alafenamide have been demonstrated. Administration of TDF/FTC PrEP has no effect on hormone levels in transmen or transwomen. PrEP is expected to be effective and safe in transpersons and should be provided to high-risk individuals regardless of gender affirming hormone use. Enzyme inducing/inhibiting antiretroviral therapy may decrease or increase, respectively, the concentrations of FHT and masculinizing hormone therapy. Unboosted integrase inhibitors or enzyme neutral non-nucleoside reverse transcriptase inhibitors are not expected to affect and are not affected by gender affirming hormones and can be considered in transmen and transwomen. Overlapping toxicities including weight gain, dyslipidaemia, cardiovascular disease and bone density effects should be considered, and antiretroviral modifications can be made to minimize toxicities. Interactions between supportive care medications should be assessed to avoid chelation interactions and hyperkalaemia.

No observed bidirectional effect between tenofovir diphosphate concentrations and gender-affirming hormone concentrations among transgender persons switching from tenofovir disoproxil fumarate/emtricitabine to tenofovir alafenamide/emtricitabine for HIV pre-exposure prophylaxis

AIMS

Many transgender and gender diverse (TGD) individuals have expressed concerns about the potential for oral pre-exposure prophylaxis to affect hormonal concentrations achieved from taking gender-affirming hormone therapy (GAHT). The purpose of this study was to understand the bidirectional effects between hormone and intraerythrocytic tenofovir diphosphate concentrations when switching from tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) to tenofovir alafenamide/emtricitabine (TAF/FTC) in TGD users/nonusers of GAHT.

METHODS

The study evaluated stored blood samples and dried blood spot cards from TGD adults without HIV who took ≥12 weeks of TDF/FTC and then switched to ≥12 weeks of TAF/FTC for pre-exposure prophylaxis.

RESULTS

Thirty-nine individuals met the study inclusion criteria. Regardless of sex assigned at birth and the use of GAHT, there were no significant differences in hormone concentrations when individuals taking GAHT were taking TDF/FTC and then switched to TAF/FTC. Further, there was no significant difference in intraerythrocytic tenofovir diphosphate concentrations between users and nonusers of GAHT.

CONCLUSION

There are no bidirectional effects between hormone and intraerythocytic tenofovir diphosphate concentrations when switching from TDF/FTC to TAF/FTC in TGD users/nonusers of GAHT.

Bidirectional pharmacokinetics of doravirine, tenofovir, and feminizing hormones in transgender women (IDentify): A randomized crossover trial

Transgender women may have concerns of drug interactions between feminizing hormone therapy (FHT) and antiretrovirals, leading to nonadherence. This randomized, three-period crossover, open-label, phase I trial assessed the effects of doravirine (DOR) and tenofovir disoproxil fumarate (TDF) on the pharmacokinetics (PKs) of estradiol, spironolactone, and total testosterone and vice versa in healthy transgender women. Volunteers were randomized 1:1 into two sequences containing three treatment groups (DOR, lamivudine [3TC], and TDF alone; estradiol, spironolactone, and placebo; and DOR/3TC/TDF, estradiol, and spironolactone). Eight subjects enrolled in the study and six had completed all study periods. The geometric mean ratios for DOR area under the concentration-time curve from zero to last measured concentration (AUC0-last ), maximum concentration (Cmax ), and concentration at 24 h (C24 ) were similar. However, tenofovir (TFV) AUC0-last , Cmax , and C24 moderately increased by 14%-38%. Last, estradiol AUC0-last , Cmax , and C24 were increased by 10%-13%. Whereas most 90% confidence intervals did not meet the bioequivalence bounds of 80%-125%, the point estimates fell within the intervals. Log-transformed DOR, TFV, and estradiol PK parameters computed with and without co-administration were not statistically different (p > 0.05). There were no serious adverse events. There is not a clinically significant impact of FHT on DOR/TFV PKs. Similarly, there is no observed impact on estradiol PKs and total testosterone following use of DOR/3TC/TDF.

Gender Affirming Hormones Do Not Affect the Exposure and Efficacy of F/TDF or F/TAF for HIV Preexposure Prophylaxis: A Subgroup Analysis from the DISCOVER Trial

Purpose

Transgender women are disproportionately affected by HIV and are underutilizing preexposure prophylaxis (PrEP). The lower uptake of PrEP by transgender women may be, in part, owing to the perception that taking PrEP may lower the efficacy of gender-affirming hormone therapy (GAHT) or to provider concerns that GAHT may lower the efficacy of PrEP.

Methods

DISCOVER was a randomized, double-blind, noninferiority trial comparing emtricitabine (FTC, F) and tenofovir alafenamide (F/TAF) versus emtricitabine and tenofovir disoproxil fumarate (F/TDF) as PrEP among transgender women and cisgender men who have sex with men (MSM). This nested substudy of the DISCOVER trial compared the exposure of the active intracellular metabolites of FTC and tenofovir (TFV), FTC triphosphate (FTC-TP) and TFV diphosphate (TFV-DP), in peripheral blood mononuclear cells (PBMC) among transgender women receiving GAHT versus MSM within the F/TAF and F/TDF groups.

Results

Our results demonstrate that TFV-DP and FTC-TP levels in PBMC were comparable between transgender women on GAHT and MSM receiving F/TAF, and between transgender women on GAHT and MSM receiving F/TDF. TFV-DP concentrations remained above the EC90 of 40 fmol/106 cells across all groups. No clinically significant drug-drug interactions of GAHT were observed with either F/TAF or F/TDF in this subanalysis.

Conclusions

These findings are consistent with the clinical pharmacology of GAHT, FTC, TDF, and TAF reported in previous studies, and support the continued use of F/TAF and F/TDF for PrEP in transgender women.

Clinicaltrials.gov registration number: NCT02842086.

Estradiol and Spironolactone Plasma Pharmacokinetics Among Brazilian Transgender Women Using HIV Pre-Exposure Prophylaxis: Analysis of Potential Interactions

BACKGROUND AND OBJECTIVE

An important barrier to HIV prevention among transgender women (TGW) is the concern that oral pre-exposure prophylaxis (PrEP) negatively affects the efficacy of feminizing hormone therapy (FHT). We aimed to assess the impact of PrEP on FHT pharmacokinetics (PK) among TGW from Brazil.

METHODS

We performed a drug-drug interaction sub-study among TGW enrolled in a daily oral PrEP demonstration study (PrEParadas, NCT03220152). Participants had a first PK assessment (PK1) 15 days after FHT (estradiol valerate 2-6 mg plus spironolactone 100-200 mg) initiation and then started PrEP (tenofovir disoproxil fumarate 300 mg/emtricitabine 200 mg). A second PK evaluation was performed 12 weeks later (PK2). Blood samples were collected prior and after the directly observed dosing (0, 0.5, 1, 2, 4, 6, 8, and 24 hours). Pharmacokinetic parameters of estradiol, spironolactone, and metabolites were estimated by non-compartmental analysis (Monolix 2021R2, Lixoft®) and compared as geometric mean ratios (GMRs, 90% confidence interval [CI]).

RESULTS

Among 19 TGW who completed the substudy, median age was 26 years (interquartile range: 23-27.5). Estradiol area under the plasma concentration-time curve (AUCτ) and trough concentrations did not differ between PK1 and PK2 evaluations (GMR [90% CI]: 0.89 [0.76-1.04] and 1.06 [0.94-1.20], respectively). Spironolactone and canrenone AUCτ were statistically lower at PK2 than PK1 (0.76 [0.65-0.89] and 0.85 [0.78-0.94], respectively). Canrenone maximum concentration was also lower at PK2 than PK1 (0.82 [0.74-0.91]).

CONCLUSION

Estradiol PK was not influenced by PrEP concomitant use. The small differences observed in some spironolactone and canrenone PK parameters should not prevent the concomitant use of estradiol-based FHT and PrEP.

TRIAL REGISTRATION

This trial (NCT03220152) was registered on July 18, 2017.