PrEP

WHAT IS PREP FOR HIV PREVENTION? 

PrEP refers to an experimental HIV prevention strategy that proposes using antiretrovirals (ARVs) to reduce the risk of HIV infection in healthy uninfected people at risk for acquiring the virus.  With PrEP, individuals would take a single drug or a combination of drugs orally, or through intramuscular injection, with the hope that it would lower the risk of infection if exposed to HIV.  There are three ARVs currently being tested in PrEP human safety and efficacy trials: tenofovir (TDF), rilpivirine (TMC278) and a combination of tenofovir and emtricitabine (FTC). Scientists have focused on these drugs because they can be conveniently taken orally once a day, may have relatively low rates of minor side effects compared to benefit when used as prevention, and because there is significant data on their long-term safety and resistance profiles in HIV positive people.  And, in the case of rilpivirine, because it can be taken in long acting formulation by injection. 

PrEP clinical trials are currently planned or underway in countries in Africa, Asia, Latin America and North America. Taken together, these trials are designed to answer questions about how PrEP works in different parts of the world, and in individuals who are exposed to HIV through anal, vaginal and intravenous routes. There are more than 17,000 volunteers participating in PrEP trials worldwide. These trials have enrolled people with different types of behaviors that might put them at risk for HIV, including injection drug use and unprotected anal or vaginal sex. It’s important to learn how PrEP works in the context of different routes of exposure (for example via injection, anal or vaginal sex.)

PREP INVESTMENT 

Global public-sector and philanthropic investment in pre-exposure prophylaxis (PrEP) over the last eight years totaled US$173 million. Funding for PrEP increased by US$8 million (18%) from US$44 million to US$52 million from 2008 to 2009. There are five ongoing oral PrEP effectiveness trials and four ongoing safety trials. In 2009, the St. Stephens AIDS Trust began a BMGF funded safety trial of Tibotec’s antiretroviral TMC278 (rilpivirine) injected intramuscularly, as a possible long-acting PrEP drug. 

PrEP can be used to describe topical use of ARVs but that research is discussed in the page dealing with microbicides.