Why Are Patients Switching from Tenofovir Disoproxil Fumarate/Emtricitabine (Truvada) to Tenofovir Alafenamide/Emtricitabine (Descovy) for Pre-Exposure Prophylaxis?

The landscape of small-molecule prodrugs

Prodrugs are derivatives with superior properties compared with the parent active pharmaceutical ingredient (API), which undergo biotransformation after administration to generate the API in situ. Although sharing this general characteristic, prodrugs encompass a wide range of different chemical structures, therapeutic indications and properties. Here we provide the first holistic analysis of the current landscape of approved prodrugs using cheminformatics and data science approaches to reveal trends in prodrug development. We highlight rationales that underlie prodrug design, their indications, mechanisms of API release, the chemistry of promoieties added to APIs to form prodrugs and the market impact of prodrugs. On the basis of this analysis, we discuss strengths and limitations of current prodrug approaches and suggest areas for future development.

Changes in Glomerular Filtration Rate After Switching From Tenofovir Disoproxil Fumarate to Tenofovir Alafenamide Fumarate for Human Immunodeficiency Virus Preexposure Prophylaxis

Background

Tenofovir alafenamide fumarate (TAF) was promoted as a safer alternative to tenofovir disoproxil fumarate (TDF) for human immunodeficiency virus oral preexposure prophylaxis (PrEP). It is unknown if switching from TDF to TAF translates to improved renal function. We used electronic health record (EHR) data to assess changes in creatinine-estimated glomerular filtration rate (eGFR) after switching from TDF to TAF.

Methods

We conducted a retrospective cohort study using EHR data from Kaiser Permanente Southern California. We identified individuals who switched from TDF to TAF between October 2019 and May 2022 and used time-varying propensity score matching to identify controls who were on TDF ("nonswitchers"). We then used Bayesian longitudinal modeling to compare differences in eGFR between switching and nonswitching scenarios.

Results

Among 5246 eligible individuals, we included 118 TDF to TAF switchers and 114 nonswitchers. Compared to nonswitchers, switchers had older age of starting TDF but similar body weights at index date. A higher proportion of switchers were White, on Medicare or Medicaid, and had dyslipidemia at index date. Switching to TAF was associated with a higher eGFR compared to staying on TDF in 3-15 months post-switch, but the differences were not statistically significant (eg, month 9 difference: 1.27 [95% credible interval, -1.35 to 3.89]). While most of the estimated changes showed eGFR increase associated with switching, most were <2 eGFR units. Sensitivity analyses to address missingness or nonadherence showed similar results.

Conclusions

Switching from TDF to TAF for PrEP was associated with a nonsignificant increase in eGFR. Findings need to be confirmed using larger cohorts.

HIV Pre-Exposure Prophylaxis Uptake Among High-Risk Population in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

Globally, 38.4 million people are affected by the human immunodeficiency virus (HIV) pandemic, and more than 2.5 million new HIV infections occur yearly. HIV pre-exposure prophylaxis (PrEP) has been widely recognized as a potential way to prevent new infections among risk population. There is a paucity of abridged evidence on the level and barriers to PrEP service uptake in sub-Saharan Africa (SSA). Therefore, we conducted a systematic review to synthesize existing evidence on PrEP uptake in SSA. Relevant studies were searched from major databases (PubMed and PsychInfo) and direct Google Scholar. Data were extracted and recorded using a pilot-tested template. Methodological rigor, heterogeneity and publication bias of studies were assessed to minimize the inclusion of erroneous findings. A random effect model was used for the meta-analysis followed by narrative metasynthesis. The protocol of this systematic review has been by registered PROSPERO (ID: CRD42022308855). A total of 1830 studies were retrieved, and 30 studies met inclusion criteria of the systematic review. People who heard about PrEP ranged from 23% to 98%. The pooled prevalence of willingness to use PrEP was 64.2% (95% confidence interval: 55.5-72.0). Fear of side effect, stigma, nonreceptive attitude, cost of pills, low awareness about PrEP, perceived reason about the effectiveness of PrEP, and lack of friendly services were the common barriers to PrEP uptake in Africa. In conclusion, comprehensive knowledge and willingness to use PrEP were low in SSA. The barriers to low PrEP service uptake are avoidable through comprehensive awareness creation and availing essential services to key population in Africa. Expanding educational messages to key population using friendly approaches and more accessible platforms, engaging stakeholders, and integrating PrEP service with routine health care are important to foster HIV prevention and control in the future.

Biktarvy for the treatment of HIV infection: Progress and prospects

Bictegravir (BIC), a second-generation integrase strand-transfer inhibitor (INSTI) with high resilience to INSTI-resistance mutations, is integrated as a key component of Biktarvy® - a fixed-dose once-daily triple-drug regimen of bictegravir (BIC), emtricitabine (FTC) plus tenofovir alafenamide (TAF). Based on the accumulated evidence from HIV clinical trials and real-world studies, the clinical effectiveness of BIC + FTC + TAF has been proven non-inferior to other fixed-dose once-daily combinations such as dolutegravir + FTC + TAF and dolutegravir + abacavir + lamivudine. Biktarvy also shows limited drug-drug interactions and a high barrier to drug resistance. According to recent HIV guidelines, BIC + FTC + TAF is recommended as initial and long-term therapy for the treatment of HIV infection. For the pre-exposure prophylaxis, tenofovir disoproxil fumarate (TDF) or tenofovir alafenamide (TAF) remains advisable, but BIC may be possibly added to TDF or TAF. In the development of a long-acting once-monthly regimen, the novel nano-formulation of BIC + FTC + TAF could be possibly developed in the future.

Use of Tenofovir Alafenamide Fumarate for HIV Pre-Exposure Prophylaxis and Incidence of Hypertension and Initiation of Statins

Importance

Pre-exposure prophylaxis (PrEP) is an important tool for preventing HIV infection. However, PrEP's impact on cardiometabolic health is understudied.

Objective

To examine the risk of incident hypertension and statin initiation among adult (age ≥18 years) health plan members starting PrEP with tenofovir alafenamide fumarate (TAF) compared with propensity score-matched adults taking tenofovir disoproxil fumarate (TDF).

Design, Setting, and Participants

This retrospective cohort study used electronic health records (EHRs) from Kaiser Permanente Southern California. Adult members starting PrEP in Kaiser Permanente Southern California between October 2019 and May 2022 were included. Propensity score matching with multiple imputation (50 matched data sets) was conducted to generate 1 TAF:4 TDF matched data sets with balanced baseline covariates.

Exposures

PrEP initiation with either TAF or TDF during the study period.

Main Outcomes and Measures

Incident hypertension and statin initiation within 2 years of PrEP initiation were ascertained through blood pressure and outpatient pharmacy records, respectively. Risk differences and odds ratios (ORs) were estimated using logistic regression and g-computation.

Results

A total of 6824 eligible individuals were identified (mean [SD] age, 33.9 [10.3] years; 6618 [97%] male). This pool was used to generate 2 cohorts without baseline hypertension or statin use for matching (hypertension: n = 5523; statin: n = 6149) In both cohorts, those starting PrEP with TAF were older and were more likely to be non-Hispanic White compared with those starting with TDF. In matched analysis adjusting for baseline covariates, TAF use was associated with elevated risk of incident hypertension (TAF: n = 371; risk difference, 0.81 [95% CI, 0.12-1.50]; OR, 1.64 [95% CI, 1.05-2.56]). TAF use was also associated with elevated risk of statin initiation (TAF: n = 382; risk difference, 0.85 [95% CI, 0.37-1.33]; OR, 2.33 [95% CI, 1.41-3.85]). Subgroup analyses restricted to individuals 40 years and older at PrEP initiation showed similar results with larger risk difference in statin initiation (risk difference, 4.24 [95% CI, 1.82-6.26]; OR, 3.05 [95% CI, 1.64-5.67]).

Conclusions and Relevance

In this study of people taking PrEP, TAF use was found to be associated with higher incident hypertension and statin initiation compared with TDF use, especially in those 40 years or older. Continued monitoring of blood pressure and lipids for TAF users is warranted.

Enzyme-Triggered l-α/d-Peptide Hydrogels as a Long-Acting Injectable Platform for Systemic Delivery of HIV/AIDS Drugs

Eradicating HIV/AIDS by 2030 is a central goal of the World Health Organization. Patient adherence to complicated dosage regimens remains a key barrier. There is a need for convenient long-acting formulations that deliver drugs over sustained periods. This paper presents an alternative platform, an injectable in situ forming hydrogel implant to deliver a model antiretroviral drug (zidovudine [AZT]) over 28 days. The formulation is a self-assembling ultrashort d or l-α peptide hydrogelator, namely phosphorylated (naphthalene-2-ly)-acetyl-diphenylalanine-lysine-tyrosine-OH (NapFFKY[p]-OH), covalently conjugated to zidovudine via an ester linkage. Rheological analysis demonstrates phosphatase enzyme instructed self-assembly, with hydrogels forming within minutes. Small angle neutron scattering data suggest hydrogels form narrow radius (≈2 nm), large length fibers closely fitting the flexible cylinder elliptical model. d-Peptides are particularly promising for long-acting delivery, displaying protease resistance for 28 days. Drug release, via hydrolysis of the ester linkage, progress under physiological conditions (37 °C, pH 7.4, H2 O). Subcutaneous administration of Napffk(AZT)Y[p]G-OH in Sprague Dawley rats demonstrate zidovudine blood plasma concentrations within the half maximal inhibitory concentration (IC50 ) range (30-130 ng mL-1 ) for 35 days. This work is a proof-of-concept for the development of a long-acting combined injectable in situ forming peptide hydrogel implant. These products are imperative given their potential impact on society.

Analysis of online user discussions on Reddit associated with the transition of use between HIV PrEP therapy

In 2019, the U.S. Food and Drug Administration (FDA) approved emtricitabine and tenofovir alafenamide (Descovy) as another option for HIV pre-exposure prophylaxis (PrEP) prevention for high-risk adults and adolescents. With the introduction of this new PrEP, millions of current users on emtricitabine and tenofovir disoproxil fumarate (Truvada), another PrEP medication currently used to prevent HIV transmission, have options of whether to continue their current treatment regime or transition to new treatment options. The objective of this study was to conduct a descriptive analysis to characterize user-generated social media conversations on Reddit associated with FDA-approved PrEP prevention treatment options. Key themes identified were associated with perceptions, knowledge, and attitudes associated with the transition of use of different PrEP medications. Data were collected retrospectively and prospectively from the Reddit platform for posts with keywords filtered for HIV, PrEP, and FDA-approved PrEP prevention treatment from October 2020 to December 2020. We chose the Reddit platform based on prior studies that have identified PrEP user conversations and insights on access challenges for specific AIDS communities, such as gays and men who have sex with men (MSM). Reddit posts were then manually annotated using an inductive content coding approach for key themes regarding the transition of use and other emergent themes from user-generated content. Formal coding of text data was conducted with refined codes, and sub-codes created. A total of 3,120 posts were analyzed from Reddit resulting in 315 posts that were coded for PrEP and 105 posts (33.33%) specific to user discussions regarding the transition of PrEP prevention. Overall, users expressed interest in drug switching to Descovy, particularly in the context of poorer adherence or concerns about existing side effects associated with Truvada. Other major themes included discussions about the cost of Descovy, apprehension about side effects in comparison to Truvada, insurance coverage changes, and discussions about the donation of Truvada to other users after transitioning. Among these discussions, topics related to sexual minorities, including MSM, reported concerns when considering a switch in their HIV prevention regime. Understanding the changing public perception associated with the introduction of new HIV prevention is important in the context of market access, patient safety, pharmacovigilance, and health equity, particularly among high-risk populations such as MSM. Results support the use of social media from a digital pharmacovigilance perspective to better understand emerging HIV prevention, treatment, and adherence challenges experienced by patients.

Weight Change When Initiating, Switching to, and Discontinuing Integrase Strand Transfer Inhibitors in People Living with HIV

Further investigations into the relationship between integrase strand transfer inhibitors (INSTIs) and weight gain are required, especially whether ceasing INSTI results in weight loss. We evaluated weight changes associated with different antiretroviral (ARV) regimens. A retrospective longitudinal cohort study was conducted using data extracted from the electronic clinical database at the Melbourne Sexual Health Centre, Australia, from 2011 to 2021. The association between weight change per time unit and ARV use in people living with HIV (PLWH) and the factors associated with weight changes when using INSTIs were estimated using a generalized estimated equation model. We included 1540 PLWH contributing 7476 consultations and 4548 person-years of data. ARV-naive PLWH initiating INSTIs gained an average of 2.55 kg/year (95% confidence interval 0.56 to 4.54; p = 0.012), while those using protease inhibitors and non-nucleoside reverse transcriptase inhibitors had no significant weight change. When switching off INSTIs, there was no significant weight change (p = 0.055). These weight changes were adjusted for age, gender, time on ARVs, and/or use of tenofovir alafenamide (TAF). Weight gain was the main reason PLWH ceased INSTIs. In addition, risk factors for weight gain in INSTI users were age younger than 60 years, male gender, and concomitant use of TAF. Weight gain was found among PLWH using INSTIs. After INSTI discontinuation, PLWH's weight stopped rising, but no weight loss was observed. Careful weight measurement after initiating INSTIs and early initiation of strategies to avoid weight gain will be important to prevent permanent weight gain and the associated morbidity.

Deep learning for topical trend discovery in online discourse about Pre-Exposure Prophylaxis (PrEP)

Pre-Exposure Prophylaxis (PrEP) interventions are increasingly prevalent on social media. These data can be mined for insights about PrEP that may not be as apparent in surveys including personal musings about PrEP and barriers/facilitators to PrEP uptake. This study explores online discourse about PrEP using an interdisciplinary public health and computational informatics approach. We collected (N = 4,020) tweets using Twitter's Application Programming Interface (API). These data underwent a three-step neural network/deep learning process to identify clusters within these tweets and relative similarity/dissimilarity between clusters. We identified 25 distinct clusters from our original collection of tweets. These clusters represent general information about PrEP, how PrEP is communicated among diverse groups, and potential pockets of misinformation and disinformation regarding PrEP. Specific clusters of interest include discussions of medication side effects, social perception of PrEP usage, and concerns with costs and barriers to access of PrEP interventions. Our approach revealed diverse ways PrEP is contextualized online. Importantly this information can be leveraged to identify points of possible intervention for disinformation and misinformation about PrEP.

Preferences Across Pre-Exposure Prophylaxis Modalities Among Young Men Who Have Sex with Men in the United States: A Latent Class Analysis Study

Access to daily oral pre-exposure prophylaxis (PrEP) is suboptimal among young cisgender men who have sex with men (YMSM) in the United States. Next-generation modalities that do not involve daily oral regimens may mitigate some of the barriers to PrEP use. We identified latent classes of YMSM based on health care decision-making patterns and examined associations between latent classes and access to health care and PrEP modality preferences (i.e., daily and event-driven oral, rectal douches, broadly neutralizing antibodies, subcutaneous implants, and an injectable). Between October 2020 and June 2021, we administered an online survey to 737 YMSM. Latent class analysis (LCA) identified groups of YMSM based on communication with providers, stigma and mistrust in health care, and autonomy in sexual health decisions. Logistic regression examined associations between class membership and health care access, and exploded logit regression examined associations between class membership and ranked PrEP modality preferences. LCA identified three classes: shared decision-making (high communication with providers and high autonomy); provider-led decision-making (high communication and low autonomy); and patient-driven decision-making (low communication and high autonomy). Shared decision-making was associated with higher access to health care in comparison with the other classes. Across all classes, YMSM preferred daily oral PrEP over all next-generation PrEP modalities. Preferences for daily oral PrEP over next-generation PrEP modalities were particularly marked among the patient-driven decision-making class. Shared decision-making is associated with access to health care and HIV prevention and higher acceptability of next-generation PrEP modalities, and should be considered as part of future interventions to promote use of daily oral and next-generation PrEP.

Validation of HIV Pre-Exposure Prophylaxis (PrEP) Medication Scales with Youth on PrEP: PrEP Confidence Scale and PrEP Difficulties Scale

Pre-exposure prophylaxis (PrEP) is a lifesaving medical intervention that protects against human immunodeficiency virus (HIV), but to date, PrEP uptake has been limited. PrEP utilization and adherence among youth, including stigmatized and highly vulnerable young sexual and gender minorities, have been exceptionally low across all regions, leading to preventable HIV transmission. Considering the scientific value of measuring and understanding predictors or associations of PrEP adherence, our study team validated two scales: a PrEP Difficulties Scale and a PrEP Confidence Scale tested within the Adolescent Trials Network P3 study (2019-2021). Data from sexual and gender minorities who were prescribed PrEP across nine domestic sites were evaluated (N = 235). Descriptive statistics, exploratory factor analysis, and correlation coefficients are reported herein. Results for the PrEP Difficulties Scale yielded a four-factor solution (Disclosure, Health Effects, Logistics, and Cost), and results for the PrEP Confidence Scale produced a three-factor solution (Scheduling, Distraction, and Planning). Factor loadings and Cronbach's alphas suggested good internal consistency for both scales. PrEP Confidence Scale subscales were correlated with PrEP adherence, and subscales of both scales were associated with dimensions of social support and PrEP-related stigma. Given the persistence of preventable HIV infections among key populations, multi-level barriers and facilitators to medication adherence, and expansion of PrEP modalities, the PrEP Difficulties Scale and PrEP Confidence Scale have the potential to enhance intervention, exploratory, and mechanistic HIV prevention research. ClinicalTrials.gov Identifier: NCT03320512.

Data Velocity in HIV-Related Implementation Research: Estimating Time From Funding to Publication

BACKGROUND

Given available effective biomedical and behavioral prevention and treatment interventions, HIV-related implementation research (IR) is expanding. The rapid generation and dissemination of IR to inform guidelines and practice has the potential to optimize the impact of the Ending the Epidemic Initiative and the HIV pandemic response more broadly.

METHODS

We leveraged a prior mapping review of NIH-funded awards in HIV and IR from January 2013 to March 2018 and identified all publications linked to those grants in NIH RePORTER through January 1, 2021 (n = 1509). Deduplication and screening of nonoriginal research reduced the count to 1032 articles, of which 952 were eligible and included in this review. Publication volume and timing were summarized; Kaplan-Meier plots estimated time to publication.

RESULTS

Among the 215 NIH-funded IR-related awards, 127 of 215 (59%) published original research directly related to the grant, averaging 2.0 articles (SD: 3.3) per award, largely in the early IR phases. Many articles (521 of 952, 55%) attributed to grants did not report grant-related data. Time from article submission to publication averaged 205 days (SD: 107). The median time-to-first publication from funding start was 4 years. Data dissemination velocity varied by award type, trending toward faster publication in recent years. Delays in data velocity included (1) time from funding to enrollment, (2) enrollment length, and (3) time from data collection completion to publication.

CONCLUSION

Research publication was high overall, and time-to-publication is accelerating; however, over 40% of grants have yet to publish findings from grant-related data. Addressing bottlenecks in the production and dissemination of HIV-related IR would reinforce its programmatic and policy relevance in the HIV response.

Dismantling Barriers and Transforming the Future of Pre-Exposure Prophylaxis Uptake in Young Black and Latinx Sexual Minority Men and Transgender Women

Pre-exposure prophylaxis (PrEP) has the potential to transform HIV in young Black and Latinx sexual minority men (SMM) and transgender women (TW). Addressing low PrEP uptake in this population depends on the better understanding of barriers to PrEP use. This article uses an ecological framework to explore barriers to daily oral PrEP in a sample of young Black and Latinx SMM and TW in three geographically prioritized cities in the United States. In-depth interviews were completed with 33 young Black and Latinx SMM and TW (22 at risk for and 11 recently diagnosed with HIV), aged 17-24, participating in a randomized trial aimed at increasing PrEP and antiretroviral therapy (ART) uptake and adherence. Interviews were recorded and transcribed, and then analyzed using inductive and deductive coding. Coded transcripts were organized into individual, interpersonal, community, and structural categories, by PrEP use and HIV status. Among participants, nine reported having been prescribed PrEP, with five actively or recently taking PrEP, whereas only one participant diagnosed with HIV had been prescribed PrEP. Major themes related to barriers emerged across the individual, family, community, and structural level. Limited barriers related to partners, instead partners with HIV encouraged PrEP use. Participants commonly reported low perceived HIV risk, fear of disclosure, barriers relating to insurance/cost, and medication use as reasons for nonuse of PrEP. For youth to remain on a healthy life course, HIV preventative measures will need to be adopted early in adolescence for those at risk of HIV acquisition. Interventions need to simultaneously address multilevel barriers that contribute to nonuse in adolescents. Clinical trials registry site and number: ClinicalTrials.gov Identifier: NCT03194477.

Considerations and challenges for sex-aware drug repurposing

Sex differences are essential factors in disease etiology and manifestation in many diseases such as cardiovascular disease, cancer, and neurodegeneration [33]. The biological influence of sex differences (including genomic, epigenetic, hormonal, immunological, and metabolic differences between males and females) and the lack of biomedical studies considering sex differences in their study design has led to several policies. For example, the National Institute of Health's (NIH) sex as a biological variable (SABV) and Sex and Gender Equity in Research (SAGER) policies to motivate researchers to consider sex differences [204]. However, drug repurposing, a promising alternative to traditional drug discovery by identifying novel uses for FDA-approved drugs, lacks sex-aware methods that can improve the identification of drugs that have sex-specific responses [7, 11, 14, 33]. Sex-aware drug repurposing methods either select drug candidates that are more efficacious in one sex or deprioritize drug candidates based on if they are predicted to cause a sex-bias adverse event (SBAE), unintended therapeutic effects that are more likely to occur in one sex. Computational drug repurposing methods are encouraging approaches to develop for sex-aware drug repurposing because they can prioritize sex-specific drug candidates or SBAEs at lower cost and time than traditional drug discovery. Sex-aware methods currently exist for clinical, genomic, and transcriptomic information [1, 7, 155]. They have not expanded to other data types, such as DNA variation, which has been beneficial in other drug repurposing methods that do not consider sex [114]. Additionally, some sex-aware methods suffer from poorer performance because a disproportionate number of male and female samples are available to train computational methods [7]. However, there is development potential for several different categories (i.e., data mining, ligand binding predictions, molecular associations, and networks). Low-dimensional representations of molecular association and network approaches are also especially promising candidates for future sex-aware drug repurposing methodologies because they reduce the multiple hypothesis testing burden and capture sex-specific variation better than the other methods [151, 159]. Here we review how sex influences drug response, the current state of drug repurposing including with respect to sex-bias drug response, and how model organism study design choices influence drug repurposing validation.

Antiretrovirals for People with HIV on Dialysis

In the era of widespread use of antiretroviral therapy (ART), people with HIV (PWH) have a near-normal life expectancy. However, PWH have high rates of kidney diseases and progression to end-stage renal disease at a younger age. PWH have multiple risks for developing acute and chronic kidney diseases, including traditional risk factors such as diabetes, hypertension, and HIV-related factors such as HIV-associated nephropathy and increased susceptibility to infections and exposure to nephrotoxic medications. Despite an improvement in access to kidney transplant among PWH, the number of PWH on dialysis continues to increase. The expansion of the number of antiretrovirals (ARVs) and kidney replacement modalities, the absence of pharmacokinetic data, and therapeutic drug monitoring make it very challenging for providers to dose ARVs appropriately leading to medication errors, adverse events, and higher mortality. Most of the recommendations are either based on small sample size studies or extrapolated based on physiochemical characteristics of ART. We aim to review the most available and most current literature on ART in PWH with renal insufficiency and ART dosing recommendations on dialysis to ensure that PWH are provided with the safest and most effective ART regimen.

A Missed Opportunity for Public Health

The paper identifies common barriers and challenges to Pre-Exposure Prophylaxis (PrEP) uptake and offers considerations for state and local public health departments to address barriers and retool infrastructure to increase access to PrEP to new users. Authors identify synergistic opportunities with federal agencies and funders to advance PrEP-related HIV prevention efforts, that prioritize strategies and investments to provide PrEP to people who could benefit from the intervention but are unaware of PrEP or struggle to access it. Barriers discussed and examined include financing strategies to reduce financial burden of PrEP medication, expanding PrEP access and outreach beyond clinical settings, and increasing the network and reach of the provider community to serve people we oppress through policy choices and discourses of racial and socioeconomic inferiority.