What is PrEP?
The term Pre-Exposure Prophylaxis (PrEP) refers to an HIV prevention practice in which persons not infected with HIV who are at high risk of the disease are take antiretroviral medication in an attempt to lower their chances of becoming infected if they are exposed to HIV.
To date, PrEP is still a subject of research, although studies have indicated it may be offer an effective prevention strategy for men who have sex with men (MSM) and sero-discordant heterosexual men and women.
In November 2010, the National Institutes of Health (NIH) announced the results of the iPrEx clinical trial, a large, multi-country research study examining PrEP. The study found that daily oral use of tenofovir plus emtricitabine (TDF/FTC, brand name Truvada) provided an average of 44% additional protection to men who have sex with men (MSM) who also received a comprehensive package of prevention services that included monthly HIV testing, condom provision, and management of other sexually transmitted infections.
In July 2011, a study by the Centers for Disease Control and Prevention (CDC) called the TDF2 study, provided evidence that a daily oral dose of antiretroviral drugs used to treat HIV infection can reduce HIV acquisition among uninfected individuals exposed to the virus through heterosexual sex. The TDF2 study, conducted in partnership with the Botswana Ministry of Health, found that once-daily TDF/FTC reduced the risk of acquiring HIV infection by roughly 63 percent overall in the study population of uninfected heterosexual men and women. CDC researchers also conducted a separate analysis to better understand the level of effectiveness among trial participants believed to be taking their study medications. This analysis excludes any HIV infections that occurred more than 30 days after a participant's last reported drug dose, because those individuals could not have been taking study pills at the time of infection. These results indicate that TDF/FTC reduced the risk of HIV infection by 78 percent.
The University of Washington study, called Partners PrEP, found that two separate antiretroviral regimens – tenofovir and TDF/FTC – significantly reduced HIV transmission among serodiscordant couples, in which one partner is infected with HIV and the other is not (by 62 percent and 73 percent, respectively). CDC co-managed two of the nine sites for this study.
In 2011, an NIH prevention clinical trial study called FEM-PrEP was halted early because an independent monitoring committee concluded that the study was be unable to demonstrate the effectiveness in preventing HIV infection in the women enrolled in the trial.
Links to information abotu additional studies are listed below.
What does it mean for my Practice?
On July 16th, the Food and Drug Administration (FDA) approved Truvada for the use of prevention of HIV in high-risk populations. The announcement signifies the approval of first medication available for pre-exposure prophylaxis (PrEP) in the United States. The Centers for Disease Control has indicated that they will release Final Guidelines on the use of PrEP, in accordance with that decision.
However, until those more detailed guidelines are available, CDC has developed Interim Guidance for physicians electing to prescribe PrEP for HIV prevention among MSM and heterosexual adults. The guidance for MSM was released in January 2011.
On August 10th, the CDC released interim guidance for clinicians considering the use of daily oral antiretroviral pre-exposure prophylaxis (PrEP) for preventing HIV infection in their heterosexually active patients. The guidance complements the PrEP recommendations released in January 2011 for MSM, but also provides guidance for heterosexually-active women and men, as well as a number of new recommendations for women of reproductive age and for couples in which one partner is HIV-positive and the other HIV-negative.
Key points from the interim guidance published in the CDC's Morbidity and Mortality Weekly Report (MMWR) include:
- PrEP should be targeted to individuals at very high risk for HIV infection, such as those whose regular sex partner is HIV-infected.
- It is critical that those using PrEP adhere consistently to the daily medication regimen.
- Clinicians should inform women considering PrEP who may become pregnant that the safety of TDF/FTC for infants exposed during pregnancy has not been fully assessed, but there is also no evidence of harm. Women who are breastfeeding should not use PrEP.
- PrEP is not a stand-alone solution: It should be delivered as part of a comprehensive package of prevention services, including counseling to reduce risk behavior and encourage adherence to the daily pill regimen, ready access to condoms and management of other sexually transmitted infections.
- Individuals prescribed PrEP must be confirmed to be HIV negative prior to use, and their HIV status, experience of side effects, medication adherence and risk behaviors must be monitored regularly during use.
View the full MMWR here.
The subject of PrEP as a policy issue is currently evolving debate in the scientific world. For more information on the subject, please visit our PrEP Policy Page, under the AAHIVM Policy and Advocacy tab.