Receptive anal sex contributes substantially to heterosexually acquired HIV infections among at-risk women in twenty US cities: Results from a modelling analysis

Tenofovir Douche as HIV Preexposure Prophylaxis for Receptive Anal Intercourse: Safety, Acceptability, Pharmacokinetics, and Pharmacodynamics (DREAM 01)

BACKGROUND

Despite highly effective HIV preexposure prophylaxis (PrEP) options, no options provide on-demand, nonsystemic, behaviorally congruent PrEP that many desire. A tenofovir-medicated rectal douche before receptive anal intercourse may provide this option.

METHODS

Three tenofovir rectal douches-220 mg iso-osmolar product A, 660 mg iso-osmolar product B, and 660 mg hypo-osmolar product C-were studied in 21 HIV-negative men who have sex with men. We sampled blood and colorectal tissue to assess safety, acceptability, pharmacokinetics, and pharmacodynamics.

RESULTS

The douches had high acceptability without toxicity. Median plasma tenofovir peak concentrations for all products were several-fold below trough concentrations associated with oral tenofovir disoproxil fumarate (TDF). Median colon tissue mucosal mononuclear cell (MMC) tenofovir-diphosphate concentrations exceeded target concentrations from 1 hour through 3 to 7 days after dosing. For 6-7 days after a single product C dose, MMC tenofovir-diphosphate exceeded concentrations expected with steady-state oral TDF 300 mg on-demand 2-1-1 dosing. Compared to predrug baseline, HIV replication after ex vivo colon tissue HIV challenge demonstrated a concentration-response relationship with 1.9 log10 maximal effect.

CONCLUSIONS

All 3 tenofovir douches achieved tissue tenofovir-diphosphate concentrations and colorectal antiviral effect exceeding oral TDF and with lower systemic tenofovir. Tenofovir douches may provide a single-dose, on-demand, behaviorally congruent PrEP option, and warrant continued development. Clinical Trials Registration . NCT02750540.

Model-based predictions of protective HIV pre-exposure prophylaxis adherence levels in cisgender women

Most human immunodeficiency virus (HIV) infections occur in cisgender women in resource-limited settings. In women, self-protection with emtricitabine/tenofovir disoproxil fumarate pre-exposure prophylaxis (FTC/TDF-PrEP) constitutes a major pillar of HIV prevention. However, clinical trials in women had inconsistent outcomes, sparking uncertainty about adherence requirements and reluctance in evaluating on-demand regimens. We analyzed data from published FTC/TDF-PrEP trials to establish efficacy ranges in cisgender women. In a 'bottom-up' approach, we modeled hypotheses in the context of risk-group-specific, adherence-efficacy profiles and challenged those hypotheses with clinical data. We found that different clinical outcomes were related to the proportion of women taking the product, allowing coherent interpretation of the data. Our analysis showed that 90% protection was achieved when women took some product. We found that hypotheses of putative male/female differences were either not impactful or statistically inconsistent with clinical data. We propose that differing clinical outcomes could arise from pill-taking behavior rather than biological factors driving specific adherence requirements in cisgender women.

HIV and syphilis testing for women and heterosexual men aged above 25 years in the Netherlands: possibilities for targeted testing at sexual health centres

OBJECTIVES

Targeted testing policy for HIV/syphilis at Dutch sexual health centres (SHCs) was evaluated for its efficiency in younger heterosexuals but not for heterosexuals ≥25 years. Currently, all older heterosexuals are tested for HIV/syphilis at SHCs. To explore possibilities for increased efficiency of testing in heterosexuals aged >25 years, this study aimed to identify determinants of HIV and syphilis diagnoses that could be used in targeted testing strategies.

DESIGN

An observational study using surveillance data from all Dutch SHC.

PARTICIPANTS

Women and heterosexual men aged >25 years visiting SHC between 2015 and 2021.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was HIV/syphilis diagnosis, determinants of a diagnosis were analysed. Based on these determinants and their applicability in SHC practice, different targeted testing scenarios were evaluated. For each scenario, the percentage of consultations involving HIV and syphilis testing and the total amount of missed HIV and syphilis diagnoses were calculated.

RESULTS

109 122 consultations were included among 75 718 individuals. The strongest determinants of HIV/syphilis diagnosis were HIV/syphilis-specific symptoms (adjusted OR (aOR) 34.9 (24.1-50.2)) and receiving partner notification (aOR 18.3 (13.2-25.2)), followed by low/middle education level (aOR 2.8 (2.0-4.0)), male sex (aOR 2.2 (1.6-3.0)) and age ≥30 years (aOR 1.8 (1.3-2.5)). When applying feasible determinants to targeted testing scenarios, HIV/syphilis testing would have been conducted in 54.5% of all consultations, missing 2 HIV and 3 syphilis diagnoses annually (13.4% and 11.4% of all diagnoses, respectively). In the scenario with the lowest number of missed HIV/syphilis diagnoses (0.3 HIV and 2 syphilis diagnoses annually), HIV/syphilis testing would have been conducted in 74.2% of all consultations.

CONCLUSIONS

In any targeted testing scenario studied, HIV and/or syphilis diagnoses would have been missed. This raises the question whether it is acceptable to put any of these scenarios into practice. This study contributes to a discussion about the impact of targeted testing policy.

Relationship between pelvic sensations and lifetime exposure to receptive anal intercourse among people with prostates

BACKGROUND

Despite the negative stigma on receptive anal intercourse (RAI), this behavior has a positive influence on individuals' sexual and relationship health. No large studies have previously looked at specific sensations experienced during RAI and how these sensations may change with experience.

AIM

In this study we aimed to quantify commonly reported pelvic sensations during RAI and determine whether their presentation changes with increasing experience of RAI.

METHODS

An internet survey was conducted on sensations felt during RAI among people with prostates from July 2022-January 2023. The survey content was developed based on a mixed-methods qualitative study and inquired about demographic and sexual histories as well as sensations (pleasure, pain, urinary, and bowel) experienced during RAI. We used descriptive statistics to describe demographic and sexual histories. All data were stratified by lifetime exposure to RAI.

OUTCOMES

The primary outcomes assessed included the quantification of both the primary sensations experienced during RAI and the associated bother.

RESULTS

In total, 975 participants completed the survey. The median age was 32 (range 18-78) years. The average age of first participation in RAI was 21 ± 6.6 years. Most respondents were having sex at least once a week (65%). Nine percent of respondents reported fewer than 10 experiences with RAI, 26% reported 11-50 RAI experiences, 32% reported 51-200 experiences, 16% reported 201-500 experiences, and 18% reported >500 experiences. As the number of experiences with RAI increased (from <10 to >500 exposures), the reported frequency of pleasurable sensation increased from 41% to 92% (P < .0001), whereas severe insertional pain and symptoms of bowel urgency decreased from 39% to 13% and from 21% to 6%, respectively (P < .0001). Urinary urgency sensation did not differ by lifetime RAI experience.

CLINICAL IMPLICATIONS

Lifetime RAI exposure can be readily assessed and correlates not only with pelvic sensation but also many other aspects of sexual health. These results imply that the etiology of dissatisfaction with pleasure or anodyspareunia during RAI may differ by lifetime RAI exposure.

STRENGTHS AND LIMITATIONS

This is the first study to our knowledge to assess pelvic sensations experienced during RAI among a large sample of individuals. This is a cross-sectional study, and we cannot conclude how pelvic sensations change over time among individuals. Internet-based participants may not be representative of clinical populations.

CONCLUSION

Lifetime exposure to RAI is positively associated with pleasure and is negatively associated with pain and bowel urgency. Pelvic sensations experienced during RAI appear to be dependent on lifetime RAI exposure history regardless of age.

Synthesis of protective oral PrEP adherence levels in cisgender women using convergent clinical- and bottom-up modeling

Globally, most HIV infections occur in heterosexual women in resource-limited settings. In these settings, female self-protection with generic emtricitabine/tenofovir disoproxil fumarate pre-exposure prophylaxis (FTC/TDF-PrEP) may constitute a major pillar of the HIV prevention portfolio. However, clinical trials in women had inconsistent outcomes, sparking uncertainty regarding risk-group specific adherence requirements and causing reluctance in testing and recommending on-demand regimen in women. We analyzed all FTC/TDF-PrEP trials to establish PrEP efficacy ranges in women. In a 'bottom-up' approach, we modeled hypotheses corroborating risk-group specific adherence-efficacy profiles. Finally, we used the clinical efficacy ranges to (in-)validate hypotheses. We found that different clinical outcomes could solely be explained by the proportion of enrolled participants not taking the product, allowing, for the first time, to unify clinical observations. This analysis showed that 90% protection was achieved, when women took some of the product. Using 'bottom-up' modelling, we found that hypotheses of putative male/female differences were either irrelevant, or statistically inconsistent with clinical data. Furthermore, our multiscale modelling indicated that 90% protection was achieved if oral FTC/TDF was taken at least twice weekly.

Longitudinal determinants of anal intercourse among women with, and without HIV in the United States

BACKGROUND

Anal intercourse (AI) is not uncommon among U.S. women and, when condomless, confers a far greater likelihood of HIV transmission than condomless vaginal intercourse. We aim to identify determinants preceding AI, among women with, and women without HIV.

METHODS

3708 women living with (73%), and without HIV (27%) participating in the Women's Interagency HIV Study provided sexual behavior and other data at 6-monthly visits over a median of 9 years (1994-2014). We used generalized estimating equation models to examine sociodemographic, structural and behavioral determinants reported in the visit preceding (1) AI, and (2) condomless AI.

RESULTS

AI was reported at least once over follow-up by 31% of women without, and 21% with HIV. AI was commonly condomless; reported at 76% and 51% of visits among women living without HIV, and with HIV, respectively. Women reporting AI were more likely to be younger (continuous variable, adjusted odds ratio (aOR) = 0.97, 95% confidence interval (CI):0.96-0.98), Hispanic (aOR = 1.88, CI:1.47-2.41) or White (aOR = 1.62, CI:1.15-2.30) compared to Black, and have at least high school education (aOR = 1.33, CI:1.08-1.65). AI was more likely following the reporting of either (aOR = 1.35, CI:1.10-1.62), or both (aOR = 1.77, CI:1.13-2.82) physical and sexual violence, excessive drinking (aOR = 1.27, CI:1.05-1.66) or any drug use (aOR = 1.34, CI:1.09-1.66), multiple male partners (aOR = 2.64, CI:2.23-3.11), exchange sex (aOR = 3.45, CI:2.53-4.71), one or more female sex partners (aOR = 1.32, CI:1.01-1.75), condomless vaginal intercourse (aOR = 1.80, CI:1.53-2.09), and high depressive symptoms (aOR = 1.23, CI:1.08-1.39).

CONCLUSION

AI disproportionally follows periods of violence victimization, substance use, multiple sex partners and depression. Better prevention messaging and biomedical interventions that reduce acquisition or transmission risk are needed, but when AI occurs in the context of violence against women, as our findings indicate, focusing on gender-based violence reduction and immediate treatment to reduce HIV transmission risk is important.

Promoting safer sex in the context of heterosexual anal intercourse: A scoping review

AIMS AND OBJECTIVES

To locate and summarise existing literature regarding safer sex practices specific to heterosexual anal intercourse and identify promising health promotion strategies.

BACKGROUND

Much of the literature regarding anal intercourse and safer sex is related to men who have sex with men. However, some studies suggest there are more women than men engaging in unprotected receptive anal intercourse. The risks associated with this sexual practice have been well documented, although many healthcare providers fail to ask about anal intercourse while addressing safer sex in the heterosexual population.

DESIGN

The study was based on Arksey and O'Malley's 2005 five-step methodology.

METHODS

A search was conducted of MEDLINE; CINAHL; PsycInfo; Cochrane; and PubMed. Databases were searched from 1990-2020. The 72 studies selected were classified according to their main area of focus. A grey literature search was also included. This scientific submission has been assessed for accuracy and completeness using the PRISMA-ScR guideline criteria (File S1).

RESULTS

The literature in this area is heterogeneous in terms of method and topic. Prevalence and incidence (n = 26) in addition to sexually transmitted infection risks (n = 26) related to heterosexual anal intercourse are well understood. However, there is limited information on condom use (n = 6), factors that influence heterosexual anal intercourse (n = 10) and health promotion strategies for this population and practice (n = 4). Two websites that mentioned heterosexual anal intercourse risk reduction activities were included.

CONCLUSIONS

Although heterosexual anal intercourse appears to be an increasingly common sexual practice, very little is known about health promotion strategies nurses might use for encouraging safer sex in this population.

RELEVANCE TO CLINICAL PRACTICE

Increased awareness of the prevalence and risks of heterosexual anal intercourse could enhance nurses' harm reduction strategies. Screening for sexually transmitted infections may be based on incorrect assumptions about sexual practices or due to stigma linked with anal intercourse. Reducing unprotected heterosexual anal intercourse will reduce sexually transmitted infections and their long-term sequelae.

The effect of depot medroxyprogesterone acetate on tenofovir alafenamide in rhesus macaques

Prevention of HIV infection and unintended pregnancies are public health priorities. In sub-Saharan Africa, where HIV prevalence is highest, depot medroxyprogesterone acetate (DMPA) is widely used as contraception. Therefore, understanding potential interactions between DMPA and antiretrovirals is critical. Here, we use a macaque model to investigate the effect of DMPA on the pharmacology of the antiretroviral tenofovir alafenamide (TAF). Female rhesus macaques received 30 mg of DMPA (n = 9) or were untreated (n = 9). Macaques received a human equivalent dose of TAF (1.5 mg/kg) orally by gavage. Tenofovir (TFV) and TFV-diphosphate (TFV-DP) were measured in blood, secretions, and tissues over 72 h. The median area under the curve (AUC_0-72h) values for TFV-DP in peripheral blood mononuclear cells were similar in DMPA-treated (6991 fmol*h/10⁶ cells) and untreated controls (5256 fmol*h/10⁶ cells) (P = 0.174). Rectal tissue TFV-DP concentrations from DMPA+ animals [median: 20.23 fmol/mg of tissue (range: 4.94-107.95)] were higher than the DMPA- group [median: below the limit of quantification (BLOQ-11.92)], (P = 0.019). TFV-DP was not detectable in vaginal tissue from either group. A high-dose DMPA treatment in macaques was associated with increased rectal TFV-DP levels, indicating a potential tissue-specific drug-drug interaction. The lack of detectable TFV-DP in the vaginal tissue warrants further investigation of PrEP efficacy with single-agent TAF products. DMPA did not affect systemic TAF metabolism, with similar PBMC TFV-DP in both groups, suggesting that DMPA use should not alter the antiviral activity of TAF.