Biomedical prevention spotlighted at AIDS 2014
Data presented at the recent AIDS 2014 international conference indicates that oral HIV pre-exposure prophylaxis (PrEP) provides a high degree of protection against HIV infection, even for individuals who miss some daily doses.1
Executive Summary
Data presented at the AIDS 2014 international conference indicates that oral HIV pre-exposure prophylaxis (PrEP) provides a high degree of protection against HIV infection, even for individuals who miss some daily doses.
- Some speculation has arisen that PrEP access could cause individuals to increase their sexual risk-taking behavior. However, results of the current trial indicate no such evidence.
- PrEP is now included as part of a range of options in preventing HIV in men who have sex with men in new guidance issued by the World Health Organization. The guidance advises that PrEP be used as an additional option to prevent HIV infection, alongside the use of condoms.
Findings from the study are particularly important in relation to emerging guidelines recommending expanded use of PrEP, said Robert Grant, MD, MPH, senior investigator at the Gladstone Institutes in San Francisco and professor of medicine at the University of California, San Francisco. The project provides critical insight into what happens as PrEP transitions from clinical trials to clinical practice, noted Grant in a release accompanying his conference presentation.
In the cohort study, men and transgender women who have sex with men who were previously enrolled in the ATN 082, iPrEx, and U.S. Safety Study PrEP trials were enrolled in a 72-week open-label extension. Scientists measured drug concentrations in plasma and dried blood spots in seroconverters and a random sample of seronegative participants. Investigators then assessed PrEP uptake, adherence, sexual practices, and HIV incidence.
A total of 1,603 HIV-negative people were enrolled; 1,225 (76%) received PrEP. Researchers report that PrEP uptake was high when made available free of charge by experienced providers. The effect of PrEP is increased by greater uptake and adherence during periods of higher risk, data indicates.1
Study findings suggest PrEP is highly effective at preventing HIV in in the study population, even when some doses of the daily regimen were missed. No study participant who took PrEP four or more times per week became HIV-infected, data suggests. "Daily dosing of PrEP is recommended, because it helps foster the habit of consistent PrEP use and increases drug levels in the body, providing the best safety cushion for individuals who occasionally miss doses," said Grant. "At the same time, these results demonstrate that PrEP remains highly effective, even in real-world circumstances in which adherence may not be perfect."
Some speculation has arisen that access to PrEP could cause individuals to increase their sexual risk-taking behavior. However, results of the current trial indicate no evidence of "risk compensation" among PrEP users. Sexual practices among PrEP receivers and those not receiving PrEP became safer by self-report, researchers note. Syphilis incidence, a marker of sexual risk behavior, was comparable between the two groups, the data reflect.1
Of the 1,603 study participants, 41 (2.6%) became HIV positive during the study. Thirteen of these were in the group that had elected not to take PrEP (annual incidence rate, 2.6%), while 28 were in the majority who had elected to receive PrEP (annual incidence rate 1.8%). Seven of these participants had actually stopped taking PrEP more than two months before they became HIV positive, in five cases because of side effects.1
WHO issues new guidance
AIDS conference attendees also received information on the World Health Organization’s (WHO’s) new guidelines on HIV prevention, diagnosis, treatment, and care for key populations.2 The new guidance addresses PrEP as part of a range of options in preventing HIV in men who have sex with men.
The guidelines consolidate WHO’s HIV advice for five "key population" groups: men who have sex with men (MSM), injecting drug users, sex workers, transgender people, and people in prisons. While progress has been made in HIV prevention, rates of HIV infection among these groups remain high, the WHO reports. "For example, recent data indicates that men who have sex with men are up to 19 times more likely to have HIV than the general population — transgender women are almost 50 times more likely," noted the WHO in a question-and-answer sheet on the new guidance.3 "Recent UNAIDS analysis suggests that up to 50% of all new infections globally are among these population groups."
According to the new guidance, it is important that men who have sex with men can access the entire range of HIV services, including antiretroviral therapy for those with HIV, and a full package of prevention options, including condoms and lubricants. The agency also recommends men who have sex with men consider using PrEP as an additional option to prevent HIV infection, alongside the use of condoms.
"WHO recognizes that PrEP will not be an appropriate choice for all men who have sex with men and supports offering men who have sex with men the full range of prevention options to suit their circumstances, taking into account their risks and preferences," the guidance states.
Get PrEP in practice
Now that evidence is available on the efficacy and effectiveness of oral daily PrEP with tenofovir disoproxil fumarate and emtricitabine (Truvada, Gilead Sciences, Foster City, CA) for HIV prevention among men who have sex with men, along with guidance from the WHO guidance and Centers for Disease Control and Prevention, and Food and Drug Administration approval, the crucial next steps for PrEP are in implementation, says Chris Beyrer, MD, professor in the Epidemiology Department in the Bloomberg School of Public Health at Johns Hopkins University (JHU) in Baltimore. Beyrer, who serves as director of JHU’s Training Program in HIV Epidemiology and Prevention Science and the Center for Public Health & Human Rights, is the president of the International AIDS Society.
The United States is the only country actively using PrEP for any population, notes Beyrer. "There are multiple demonstration projects underway in many settings, and these are important," observes Beyrer. "But critically important now for countries with HIV epidemics ongoing among MSM is to begin implementation of this new tool as a prevention strategy for the individual, and as part of public health programs to begin to have an impact on HIV among MSM at network and community levels."
Public health officials need to take PrEP to scale in epidemic contexts where high HIV incidence densities are being seen among these men, says Beyrer. This effort will require provider and community education and training efforts, appropriate testing and counseling services, negotiations over drug and other program costs, and efforts on the regulatory and other policy fronts, he states.
"We have delayed too long and seen too many young men become HIV infected, in both developed and developing countries, to delay implementation further," states Beyrer.
REFERENCES
- Grant RM, Anderson PL, McMahan V, et al. Uptake of pre-exposure prophylaxis, sexual practices, and HIV incidence in men and transgender women who have sex with men: a cohort study. Lancet Infect Dis 2014; doi:10.1016/S1473-3099(14)70847-3.
- World Health Organization. Consolidated Guidelines on HIV Prevention, Diagnosis, Treatment and Care for Key Populations. Geneva; 2014.
- World Health Organization. Q&A: WHO Consolidated guidelines on HIV prevention, diagnosis, treatment and care for key populations. Accessed at http://bit.ly/1rODKVP.
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