The rate of acquiring human immunodeficiency virus (HIV) was extremely low despite a high incidence of sexually transmitted infections (STIs) in a study where pre-exposure antiretroviral medication to prevent HIV infection was dispensed at clinics in three metropolitan areas heavily affected by HIV, according to a new study.
Clinics that treat STIs and community-based clinics serving men who have sex with men (MSM) are promising sites to deliver pre-exposure prophylaxis (PrEP) for HIV. Men who have sex with men account for more than two-thirds of new HIV infections in the US. Previous randomised clinical trials have demonstrated the efficacy of PrEP in preventing HIV infection. However, little is known about adherence to the PrEP regimen, sexual practices and overall effectiveness when PrEP is implemented at STI and community-based clinics serving MSM.
Dr Albert Y Liu, of the San Francisco Department of Public Health, and co-authors report on the results of a demonstration project that assessed PrEP adherence, sexual practices and incidence of STIs and HIV infection among MSM and transgender women in San Francisco, Miami and Washington, DC.
The project enrolled participants from two municipal STI clinics in San Francisco and Miami and at a community health centre in Washington from October 2012 through January 2014 with final follow-up in February 2015. PrEP was provided free of charge to participants for 48 weeks as a combination of daily, oral tenofovir disoproxil fumarate and emtricitabine. Patients also received HIV testing, brief client-centred counselling and clinical monitoring. Sexual behaviours were assessed by questionnaire.
Overall, 557 participants initiated PrEP and 437 of them (78.5%) were retained in the demonstration project through 48 weeks. Of the 294 participants who had their tenofovir diphosphate levels measured, 80% to 85.6% had protective levels at follow-up visits. Participants who were African American and those from the Miami clinic were less likely to have protective levels. Participants who had stable housing and those who reported at least two condomless anal sex partners in the past three months were more likely to have protective levels. The average number of anal sex partners declined during follow-up from 10.9 at baseline to 9.3 at week 48, while the proportion of participants engaging in condomless receptive anal sex remained stable from 65.5% at baseline, according to the results.
Overall, the incidence of STI was high (90 per 100 person-years) but did not increase over time. Two individuals became HIV infected during the follow-up for an HIV incidence of 0.43 infections per 100 person-years, the data indicate. The first infection was detected about 19 weeks after study enrolment and the second was detected about four weeks after the 48-week visit when the study drug was no longer dispensed. Both participants had tenofovir diphosphate levels consistent with taking fewer than two doses per week around the time of HIV infection, the authors explain.
Study limitations reported by the authors include under representation of the African American and transgender participants in the study, the results may not be generalisable to broader MSM populations, and the cost and lack of insurance coverage may be barriers to PrEP access outside of the study.
“Adherence was higher among those participants with more reported risk behaviours. These results provide support for expanding PrEP implementation in MSM in similar clinical settings and highlight the urgent need to increase PrEP awareness and engagement and to develop effective adherence support for highly affected African American and transgender populations,” the authors conclude.
In a related commentary, Dr Raphael J. Landovitz, of the David Geffen School of Medicine at UCLA, Los Angeles, writes: “Overall, the news concerning PrEP dissemination is good, but there are sobering lessons. … Realising the benefits of PrEP requires an optimal cascade of events that is remarkably similar to the Gardner Cascade of engagement in care for those infected with HIV. The so-called PrEP cascade requires identification of at-risk individuals, promotion of interest and knowledge of PrEP, linkage to PrEP-knowledgeable clinics, and PrEP initiation, persistence and adherence. The benefits of PrEP will only fully be realised when we can identify ways of successfully moving persons at a high risk of HIV infection through this cascade.”
Importance: Several randomized clinical trials have demonstrated the efficacy of preexposure prophylaxis (PrEP) in preventing human immunodeficiency virus (HIV) acquisition. Little is known about adherence to the regimen, sexual practices, and overall effectiveness when PrEP is implemented in clinics that treat sexually transmitted infections (STIs) and community-based clinics serving men who have sex with men (MSM).
Objective: To assess PrEP adherence, sexual behaviors, and the incidence of STIs and HIV infection in a cohort of MSM and transgender women initiating PrEP in the United States.
Design, Setting, and Participants: Demonstration project conducted from October 1, 2012, through February 10, 2015 (last date of follow-up), among 557 MSM and transgender women in 2 STI clinics in San Francisco, California, and Miami, Florida, and a community health center in Washington, DC. Data were analyzed from December 18, 2014, through August 8, 2015.
Interventions: A combination of daily, oral tenofovir disoproxil fumarate and emtricitabine was provided free of charge for 48 weeks. All participants received HIV testing, brief client-centered counseling, and clinical monitoring.
Main Outcomes and Measures: Concentrations of tenofovir diphosphate in dried blood spot samples, self-reported numbers of anal sex partners and episodes of condomless receptive anal sex, and incidence of STI and HIV acquisition.
Results: Overall, 557 participants initiated PrEP, and 437 of these (78.5%) were retained through 48 weeks. Based on the findings from the 294 participants who underwent measurement of tenofovir diphosphate levels, 80.0% to 85.6% had protective levels (consistent with ≥4 doses/wk) at follow-up visits. African American participants (56.8% of visits; P = .003) and those from the Miami site (65.1% of visits; P < .001) were less likely to have protective levels, whereas those with stable housing (86.8%; P = .02) and those reporting at least 2 condomless anal sex partners in the past 3 months (88.6%; P = .01) were more likely to have protective levels. The mean number of anal sex partners declined during follow-up from 10.9 to 9.3, whereas the proportion engaging in condomless receptive anal sex remained stable at 65.5% to 65.6%. Overall STI incidence was high (90 per 100 person-years) but did not increase over time. Two individuals became HIV infected during follow-up (HIV incidence, 0.43 [95% CI, 0.05-1.54] infections per 100 person-years); both had tenofovir diphosphate levels consistent with fewer than 2 doses/wk at seroconversion.
Conclusions and Relevance: The incidence of HIV acquisition was extremely low despite a high incidence of STIs in a large US PrEP demonstration project. Adherence was higher among those participants who reported more risk behaviors. Interventions that address racial and geographic disparities and housing instability may increase the impact of PrEP.