Purpose of review

Tenofovir-based oral PrEP has been effective in reducing population-level HIV incidence in multiple settings, although disparities remain. Injectable cabotegravir-based PrEP is an alternative that may be attractive to individuals with adherence challenges or who do not desire to take a daily medication. We review promises and challenges of cabotegravir-based PrEP.

Recent findings

Cabotegravir has demonstrated higher effectiveness than oral PrEP in two randomized trials, with a hazard ratio of 0.31 for HIV incidence among MSM and transgender women across multiple settings [95% confidence interval (CI) 0.18-0.62] and 0.11 for cisgender women in sub-Saharan Africa (95% CI 0.040.32). Cabotegravir was also highly effective among populations with disproportionate HIV incidence. Although cabotegravir breakthrough was rare, diagnosis was delayed with use of antigen/antibody-based HIV tests, and resistance occurred with breakthrough infections. Implementation will need to overcome several challenges, including HIV RNA laboratory monitoring not being widely available, requirement for additional staff time and clinic space, and need to provide oral medication during interruptions in dosing.

Summary

Cabotegravir-based PrEP is a highly effective additional PrEP option that will expand HIV prevention options. For successful roll-out, strategies for streamlined and accessible delivery of cabotegravir in real-world settings will need to be developed.

Two multinational clinical trials have shown safety and efficacy of long-acting injectable cabotegravir for HIV pre-exposure prophylaxis (PrEP). These results will alter the landscape of HIV prevention and related research. Nevertheless, designing and conducting this research involved several ethical issues. This Viewpoint describes how we managed ethical issues over the duration of one of these trials (HPTN 083). Specifically, we discuss the rationale for pursuing a long-acting injectable agent in the presence of effective oral PrEP, trial design choices, site selection and local standards of prevention, data monitoring and early stopping, effects of the COVID-19 pandemic, post-trial access, and assessment of long-term safety.

Pre-exposure prophylaxis (PrEP) is an important biomedical intervention that may help reduce the risk of HIV transmission among transwomen. To date, little research is available to inform interventions to increase uptake and adherence to PrEP among transwomen, especially in places outside the U.S. We conducted a qualitative study in 2015 with 34 adult transwomen in Rio de Janeiro, Brazil and assessed awareness, interest, barriers and facilitators to PrEP uptake and adherence for transwomen. Almost one third of participants had heard of PrEP, and most were interested and thought it would be beneficial for transwomen in their community. Barriers to PrEP included fear of being HIV positive resulting in low HIV testing and concerns about the ability to adhere to a daily PrEP regimen. The most prominent barrier to uptake was past experiences of transgender-identity related discrimination in the universal health care system that reduced willingness to seek PrEP or health care in general. Participants recommended technological solutions to PrEP health education information that could address uptake and adherence. This study informs efforts to increase PrEP use among transwomen in Brazil.

In Brazil, little data is available to inform HIV prevention programming for travestis and transgender ('trans') women, despite the existence of a social movement that has gained strength in recent years. We conducted formative research in Rio de Janeiro to gather trans women's perspectives on combination HIV prevention approaches. Framing the analysis within the model of gender affirmation, we found that several social and contextual factors inhibited participants' access to HIV prevention and treatment. Experienced and anticipated gender-related discrimination and HIV stigma were linked to the avoidance of HIV testing, health services and HIV status disclosure. Participants recommended HIV prevention interventions which combined socio-structural interventions, such as peer-based empowerment and social support, with biomedical interventions such as pre-exposure prophylaxis (PrEP). Participants expressed a preference for programmes and interventions that emphasised a gender-affirmative approach, promoted autonomy and aimed to reduce stigma and discrimination in public health services.

The Brazilian HIV/AIDS epidemic is concentrated among men who have sex with men (MSM), however HIV testing rates among MSM are not commensurate with their risk. Strategies to expand early diagnosis may include use of self-conducted home-based testing kits, which are now available for purchase in the US. In April 2011 we conducted a survey with Brazilian MSM using Facebook to assess HIV testing preferences and acceptability of home-based testing. Among 356 previously tested, HIV-negative MSM, 47% reported a preference for home-based testing, 27% preferred clinic-based testing, and 26% had no preference. Less frequent testers and those who had considered testing but failed to test were more likely to prefer home-based testing. Close to 90% reported that they would use self-test kits; 62% and 54% said they would use home-based testing to make choices about unprotected sex with regular and new partners, respectively. Concerns included difficulty to understand the tests (32%) and receiving results alone (23%). Overall, home-based testing may appeal to MSM and result in increased testing frequency. Research on feasibility and utilization of self-tests in practice is needed.

Background

Fifty percent of people living with human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS) worldwide are female. In Brazil, for example, 240,000 women are infected with HIV, rates of infection in women have increased over the last two decades, and addressing HIV prevention and treatment for women at risk for, or living with, HIV/AIDS remains a challenge. To better address the needs of women living with HIV in Brazil, the Instituto de Pesquisa Clínica Evandro Chagas - Fundação Oswaldo Cruz (IPEC-FIOCRUZ) HIV Women's Cohort was established in 1996 to study the natural history of women seeking HIV care. This analysis describes the characteristics of women in the cohort who participated in HIV clinical trials between 1999 and 2008.

Methods

A total of 736 Women's Cohort participants were in active follow-up and 665 participants from the Women's Cohort were included in univariable and multivariable analyses to determine socioeconomic and sociodemographic factors associated with women's participation in HIV clinical trials at our site.

Results

Of the complete cohort, 23% participated in a clinical trial between January 1999 and July 2008. Odds of participation decreased for women who were younger than 35 years old, currently employed, had an HIV-positive sexual partner, and/or who reported a lifetime history of illicit drug use. Alternatively, the odds of participation increased for women who had more than 8 years of formal education, were living independently, and/or were married or cohabitating.

Conclusion

The rate of participation in HIV clinical trials by women in the IPEC-Fiocruz Cohort was similar to other published cohorts, but identification of local risk factors and barriers to participation remains important. Our analysis offers a novel description of the factors associated with participation in HIV clinical trials among women in care at IPEC-FIOCRUZ in Rio de Janeiro, Brazil.

HIV self-testing has the potential to increase testing frequency and uptake. This pilot study assessed the feasibility and acceptability of HIV self-testing in a sample of sexually active men who have sex with men (MSM) in Peru and Brazil. Participants were trained to use a whole blood rapid HIV self-test and instructed to use the self-test monthly during this three-month study. Test acceptability was measured with self-reported use of the test at the one-month and three-month study visits, and test feasibility was assessed by direct observation of self-test administration at the final three-month visit. A total of 103 participants (52 in Peru and 51 in Brazil) were enrolled, and 86% completed the three-month study. Nearly all participants reported use of the self-test (97% at one-month and 98% at three-month visit), and all participants correctly interpreted the self-administered test results when observed using the test at the final study visit. HIV self-testing with a blood-based assay was highly acceptable and feasible. HIV self-testing may have the potential to increase testing frequency and to reach high-risk MSM not currently accessing HIV-testing services.

Increasing access and frequency of human immunodeficiency virus testing are critical to stemming the epidemic. In Brazil's concentrated epidemic, human immunodeficiency virus prevalence in the men who have sex with men/transgender population far exceeds that in the general population, but testing rates fall below what is needed to ensure early detection and treatment. Over-the-counter human immunodeficiency virus self-testing kits, now available in stores in the U.S., have enormous potential to increase testing access and frequency and to facilitate early detection and treatment. With the advent of human immunodeficiency virus self-testing upon us, it is timely to engage the scientific community, government, and civil society in a dialog around how to best utilize this technology in Brazil. We summarize recent research on over-the-counter testing among men who have sex with men, raise potential questions and challenges to using self-tests, suggest implementation strategies, and outline a research agenda moving forward.

Introduction

Pharmacy adherence measures such as pharmacy dispensing ratios (PDRs) have previously been shown to be predictive of virologic outcomes. We aimed to determine the optimal interval of PDR assessment for predicting virologic failure for HIV-infected patients on antiretroviral therapy (ART).

Methods

Using national Brazilian ART pharmacy refill data, we examined PDRs for patients ≥18 years of age with at least one HIV RNA level ≥180 days after ART initiation on or after 1 January 2011. Patients with a documented ART change ≤270 days prior to viral load test date were excluded. Logistic regression models were used to describe associations between virologic failure, defined as an HIV RNA level ≥400 copies/mL and PDRs, defined as the number of days index drug dispensed (non-nucleoside reverse-transcriptase inhibitor or protease inhibitor) per 180- and 90-day, interval preceding viral load testing, adjusting for sex, age, race, time since ART initiation and index drug. Backward elimination of insignificant variables was performed after adjusting for PDR. A predictive probability of virologic failure was calculated using the corresponding odds ratios for the PDR and any other significant variables. The diagnostic performance of the PDR interval was assessed by calculating the area under the receiver operating characteristic curve (AUROC) for the predictive probability with respect to virologic failure. Results and Discussion A total of 1,025 patients were included (68% were male, median age 40 years, median time on ART 3.4 years). The PDR was found to be significantly associated with virologic failure for all of the PDR intervals (p < 0.001). There was an increased risk of virologic failure for all PDRs <0.95. The 90-180 days interval had a AUROC of 0.842, compared to 0.841 and 0.829 for the 0-180 days and 0-90 days intervals, respectively. The PDR performed well as a predictive tool to identify patients in virologic failure with the 90-180-days interval prior to viral load testing being marginally more predictive.

Conclusions

The validation and use of the pharmacy dispensing ratio using public pharmacy refill data could aid in early identification of patients with poor adherence and prevent development of treatment failure and drug resistance in Brazil.