Meeting the goal of concurrent adolescent and adult licensure of HIV prevention and treatment strategies

Competence to Consent to Oral and Injectable PrEP Trials Among Adolescent Males Who Have Sex with Males

Adherence to oral pre-exposure prophylaxis (PrEP) is challenging for adolescent males who have sex with males (AMSM). Once adult trials comparing oral to longer lasting injectable PrEP are completed, there will be a need for adolescent studies. However, lack of data on adolescent consent capacity may sustain guardian permission requirements identified as a barrier to AMSM participation in prior PrEP trials. This online study assessed AMSM's (14-17 years) consent capacity for these trials, comparing performance to MSM (18-19 years) for whom guardian permission is not required. Applying the MacCAT-CR, participants (N = 214) viewed a video and mock consent form followed by open-ended and yes/no items. Cognitive diagnostic models and means testing analyses supported AMSM capacity to consent to these trials: 16-17 and most 14-15 year-olds, demonstrated consent understanding, appreciation and reasoning at 18-19 year-old levels. Data also identified vulnerabilities requiring attention during informed consent.

Modeling the Impact of PrEP Programs for Adolescent Sexual Minority Males Based on Empirical Estimates for the PrEP Continuum of Care

PURPOSE

Pre-exposure prophylaxis (PrEP)-an effective and safe intervention to prevent HIV transmission-was recently approved by the Food and Drug Administration for use by adolescents. Informed by studies of sexual behavior and PrEP adherence, retention, and promotion, we model the potential impact of PrEP use among at-risk adolescent sexual minority males.

METHODS

We simulate an HIV epidemic among men who have sex with men (MSM) aged 13-39. We assume adult MSM ages 19-39 have had PrEP available for 3 years with 20% coverage among eligible MSM based on the Centers for Disease Control and Prevention guidelines. PrEP interventions for ages 16-18 are then simulated using adherence and retention profiles drawn from the ATN113 and Enhancing Preexposure Prophylaxis in Community studies across a range of uptake parameters (10%-100%). Partnerships across age groups were modeled using parameterizations from the RADAR study. We compare the percent of incident infections averted (impact), person-years on PrEP per infection averted (efficiency), and changes in prevalence over 10 years.

RESULTS

As compared to no PrEP use, baseline PrEP adherence and retention among adolescent sexual minority males drawn from the ATN113 and Enhancing Preexposure Prophylaxis in Community studies averted from 2.8% to 41.0% of HIV infections depending on the fraction of eligible adolescent sexual minority males that initiated PrEP at their annual health-care visit. Improved adherence and retention achieved with an array of focused interventions from real-world settings increased the percent of infections averted by as much as 26%-70%.

CONCLUSIONS

Empirically demonstrated improvements in the PrEP continuum of care in response to existing interventions can substantially reduce incident HIV infections among adolescent sexual minority males.

Measuring research mistrust in adolescents and adults: Validity and reliability of an adapted version of the Group-Based Medical Mistrust Scale

Mistrust of health care providers among persons of color is a significant barrier to engaging them in research studies. Underrepresentation of persons of color is particularly problematic when the health problem under study disproportionately affects minoritized communities. The purpose of this study was to test the validity and reliability of an abbreviated and adapted version of the Group Based Medical Mistrust Scale. The GBMMS is a 12-item scale with three subscales that assess suspicion, experiences of discrimination, and lack of support in the health care setting. To adapt for use in the research setting, we shortened the scale to six items, and replaced “health care workers” and “health care” with “medical researchers” and “medical research,” respectively. Using panelists from a market research firm, we recruited and enrolled a racially and ethnically diverse sample of American adults (N = 365) and adolescents aged 14–17 (N = 250). We administered the adapted scale in a web-based survey. We used Cronbach’s alpha to evaluate measure internal reliability of the scale and external factor analysis to evaluate the relationships between the revised scale items. Five of the six items loaded onto a single factor, with (α = 0.917) for adolescents and (α = 0.912) for adults. Mean scores for each item ranged from 2.5–2.9, and the mean summary score (range 6–25) was 13.3 for adults and 13.1 for adolescents. Among adults, Black respondents had significantly higher mean summary scores compared to whites and those in other racia/ethnic groups (p<0.001). There was a trend toward significance for Black adolescents as compared to white respondents and those in other racial/ethnic groups (p = 0.09). This five-item modified version of the GBMMS is reliable and valid for measuring research mistrust with American adults and adolescents of diverse racial and ethnic identities.

Adolescent participation in HIV research: consortium experience in low and middle-income countries and scoping review

Adolescents in low and middle-income countries (LMICs) have a high prevalence of HIV, therefore, it is important that they are included in HIV research. However, ethical challenges regarding consent can hinder adolescent research participation. We examined examples from the Prevention and Treatment Through a Comprehensive Care Continuum for HIV-affected Adolescents in Resource Constrained Settings (PATC3H) research consortium, which investigates adolescent HIV prevention and treatment in seven LMICs: Brazil, Kenya, Mozambique, Nigeria, South Africa, Uganda, and Zambia. PATC3H researchers were asked to identify ethical and practical challenges of adolescent consent to research participation in these countries. We also did a scoping review of strategies that could improve adolescent participation in LMIC HIV studies. Examples from PATC3H research highlighted many ethical challenges that affect adolescent participation, including inconsistent or absent consent guidance, guidelines that fail to account for the full array of adolescents' lives, and variation in how ethical review committees assess adolescent studies. Our scoping review identified three consent-related strategies to expand adolescent inclusion: waiving parental consent requirements, allowing adolescents to independently consent, and implementing surrogate decision making. Our analyses suggest that these strategies should be further explored and incorporated into ethical and legal research guidance to increase adolescent inclusion in LMIC HIV research.

The HIV drug optimization agenda: promoting standards for earlier investigation and approvals of antiretroviral drugs for use in adolescents living with HIV

INTRODUCTION

Most clinical trials for new antiretroviral (ARV) agents are conducted among narrowly defined adult populations. Only after safety and efficacy have been clearly demonstrated among adults living with HIV are trials including adolescents, children and infants conducted. This approach contributes to significant delays in the availability of optimal new ARV regimens for infants, children and adolescents. This commentary discusses issues related to the inclusion of adolescents aged 12 to 18 years in initial HIV clinical phase 3 trials of novel antiretrovirals (ARVs) or conducting parallel phase 3 clinical trials among adolescents.

DISCUSSION

The absorption, metabolic and excretion or elimination pathways for drugs do not significantly differ between adolescents and adults. In fact, dosing recommendations for ARVs are the same for adults and adolescents who meet the age and weight criteria. Although conducting clinical trials among adolescents present special challenges (e.g. consenting minors and concerns about trial completion and contraception), these challenges can be addressed to obtain high-quality trial results. Importantly, new agents and optimized combinations have more favourable dosing schedules and side-effect profiles and are more effective ARV agents with higher HIV drug resistance thresholds, which would be extremely beneficial to improve outcomes among HIV-positive adolescents.

CONCLUSIONS

Adolescents may not present with significantly different pharmacokinetic characteristics from those in adults. Including HIV-positive adolescents in phase 3 ARV clinical trials, either with adults or in specific adolescent studies conducted in parallel, would allow adolescents to access promising, more effective treatment for HIV years earlier than with the current stepwise approach.

Dosing Common Medications in Hospitalized Pediatric Patients with Obesity: A Review

Medication management in children and adolescents with obesity is challenging because both developmental and pathophysiological changes may impact drug disposition and response. Evidence to date indicates an effect of obesity on drug disposition for certain drugs used in this population. This work identified published studies evaluating drug dosing, pharmacokinetics (PK), and effect in pediatric patients with obesity, focusing on 70 common medications used in a pediatric network of 42 US medical centers. A PubMed search revealed 33 studies providing PK and/or effectiveness data for 23% (16 of 70) of medications, 44% of which have just one study and can be considered exploratory. This work appraising 4 decades of literature shows several promising approaches: greater use of PK models applied to prospective clinical studies, dosing recommendations derived from both PK and safety, and multiyear effectiveness data on drugs for chronic conditions (e.g., asthma). Most studies make dose recommendations but are weakened by retrospective study design, small study populations, and no controls or historic controls. Dosing decisions continue to rely on extrapolating knowledge, including targeting systemic drug exposure typically achieved in adults. Optimal weight-based dosing strategies vary by drug and warrant prospective, controlled studies incorporating PK and modeling and simulation to complement clinical assessment.

Innovative Approaches to Obtain Minors' Consent for Biomedical HIV Prevention Trials: Multi-Site Quasi-Experimental Study of Adolescent and Parent Perspectives

BACKGROUND

Despite the high burden of new HIV infections in minor adolescents, they are often excluded from biomedical HIV prevention trials, largely owing to the ethical complexities of obtaining consent for enrollment. Researchers and ethics regulators have a duty to protect adolescents-as a special category of human subjects, they must have protection that extends beyond those afforded to all human subjects. Typically, additional protection includes parental consent for enrollment. However, parental consent can present a risk of harm for minor adolescents. Research involving minor adolescents indicate that they are unwilling to join biomedical trials for stigmatized health problems, such as HIV, when parental consent is required. This presents a significant barrier to progress in adolescent HIV prevention by creating delays in research and the translation of new scientific evidence generated in biomedical trials in adult populations.

OBJECTIVE

This protocol aims to examine how parental involvement in the consent process affects the acceptability of hypothetical participation in biomedical HIV prevention trials from the perspectives of minor adolescents and parents of minor adolescents.

METHODS

In this protocol, we use a quasi-experimental design that involves a simulated consent process for 2 different HIV prevention trials. The first trial is modeled after an open-label study of the use of tenofovir disoproxil fumarate and emtricitabine as preexposure prophylaxis for HIV. The second trial is modeled after a phase IIa trial of an injectable HIV integrase inhibitor. There are 2 groups in the study-minor adolescents aged 14 to 17 years, inclusive, and parents of minor adolescents in the same age range. The adolescent participants are randomized to 1 of 3 consent conditions with varying degrees of parental involvement. After undergoing a simulated consent process, they rate their willingness to participate (WTP) in each of the 2 trials if offered the opportunity. The primary outcome is WTP, given the consent condition. Parents undergo a similar process but are asked to rate the acceptability of each of the 3 consent conditions. The primary outcome is acceptability of the consent method for enrollment. The secondary outcomes include the following: capacity to consent among both participant groups, the prevalence of medical mistrust, and the effects of the study phase (eg, phase IIa vs the open-label study) and drug administration route (eg, oral vs injection) on WTP (adolescents) and acceptability (parents) of the consent method.

RESULTS

Enrollment began in April 2018 and ended mid-September 2019. Data are being analyzed and dissemination is expected in April 2020.

CONCLUSIONS

The study will provide the needed empirical data about minor adolescents' and parents' perspectives on consent methods for minors. The evidence generated can be used to guide investigators and ethics regulators in the design of consent processes for biomedical HIV prevention trials.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/16509.

HIV Prevention Interventions for Adolescents

PURPOSE OF REVIEW

The goal of this paper is to review recent data on biomedical, behavioral, and structural HIV prevention interventions for adolescents and young adults.

RECENT FINDINGS

While it is accepted that HIV prevention interventions must take an integrated approach to achieve maximum effectiveness, to date, there have been limited, rigorously evaluated combination prevention interventions for adolescents. There are currently a range of effective biomedical, behavioral, and structural approaches that can be integrated into prevention packages to address the prevention needs of adolescents, including oral PrEP, male circumcision, rapid HIV testing, numerous behavioral interventions, and structural interventions such as cash transfers and community mobilization to address gender-based violence. There is still a need for rigorously evaluated, innovative combination prevention packages for adolescents. Prevention approaches must take into account the context of young people's lives and address the multiple levels of influence on their lives including parents, partners, and communities.

Advancing HIV Biomedical Prevention Research for At-Risk Adolescents

Despite significant additions to the HIV prevention toolbox, infection rates across the United States continue to rise among vulnerable adolescents and young adults. Access to these interventions by youth at risk for HIV is limited by the lack of data about their safety and use, compounding the myriad contextual barriers to effectively preventing HIV in this group. The NIH-funded Adolescent Trials Network implemented an innovative approach to the inclusion of adolescents at risk for HIV infection who consented for their own participation in the first adolescent study of HIV pre-exposure prophylaxis (PrEP). This model of mature minor consent was supported by state-based adolescent treatment statutes that extend an adolescent's ability to consent to participation in research with a sufficient prospect of clinical benefit from the intervention to justify the potential risks, and a balance of benefits and risks that is at least as favorable as available evidence-based alternatives. Important data on the safety and patterns of PrEP use by at-risk adolescents prompted the FDA to revise the label. The expanded indication of PrEP for HIV prevention in adolescents is hoped to inform clinical guidelines and provides a powerful tool to reduce new infections in the United States among vulnerable at-risk adolescents. Lessons learned from this years-long iterative endeavor have implications for improving access to the rapidly evolving landscape of HIV prevention modalities, including recently implemented studies of long-acting PrEP formulations designed to reduce the burden of daily adherence required by oral PrEP, a major clinical pitfall for adolescent clinicians and their patients.