Fact Sheet

The global toll of new HIV infections – 2.7 million new HIV infections occurred in 2007 alone, about 50,000 new infections every week -- demonstrates the urgent need for effective new HIV prevention tools.  Existing prevention methods such as education, counseling, condom use and male circumcision are important in reducing the number of HIV infections, but have not been sufficient to stop the epidemic.  Other potential prevention methods, such as a safe and effective vaccine against HIV, do not yet exist.

Pre-exposure prophylaxis (PrEP), therapy taken to prevent rather than treat an infection or illness, is one strategy being studied as part of its effort to develop new HIV prevention tools. In monkey studies, treatment with HIV antiretroviral drugs significantly reduced infections among monkeys exposed to the simian version of HIV.  In humans, HIV has also been shown to be vulnerable to this type of pre-infection intervention.  For example, antiretroviral treatment of an HIV-infected mother during childbirth reduces an infant’s chance of contracting the virus by about 75 percent.  Treatment with anti-HIV drugs can also significantly reduce the risk of infection when taken immediately after exposure to the virus.   

The Pre Exposure Prophylaxis Initiative (iPrEx)

The iPrEx study is a Phase III trial, sponsored by the US-National Institutes of Health (NIH) with co-funding from the Bill and Melinda Gates Foundation and study medication donated by Gilead Sciences.  The study is designed to determine whether the use of the single tablet HIV antiretroviral drug, a co-formulation of tenofovir disoproxil fumarate and emtricitabine, taken daily may help prevent HIV infection among people at high risk, when combined with safer sex counseling, condoms and STI management.  This study is conducted by highly qualified scientists and researchers in Peru, Ecuador, the United States, South Africa, Brazil and Thailand. 

The study has enrolled more than 2300 volunteers of a total target enrollment of 3000 healthy, sexually active HIV-negative men who have sex with men (MSM) who are at high risk of contracting HIV.  The study is being conducted at eleven locations: two sites in Lima, Peru, one in Iquitos, Peru; one in Guayaquil, Ecuador; and one site each in Boston and San Francisco, in the United States, one site in Cape Town, South Africa and two sites in Rio de Janeiro, and one site in Sao Paulo, Brazil and one site in Chiang Mai, Thailand.

All study participants receive condoms and counseling on how to prevent HIV infection, along with medical care for any sexually transmitted infections.  Half of the enrollees receive the study drug (tenofovir/emtricitabine), and half receive a placebo.  Neither the study personnel nor the volunteers know who is receiving the study drug and who is receiving placebo. Study volunteers receive safer sex counseling and are tested for HIV and for other sexually transmitted infections monthly. In addition to extensive safer sex counseling, volunteers are counseled that, even if they receive the study drug, there is no assurance that the drug will offer any protection against HIV…meaning safer sex precautions should always be used.

At the end of the study, the investigators will compare the number of HIV infections in the group that received the study drug to those in the group that received placebo, to determine whether tenofovir/emtricitabine can effectively help to prevent HIV infection when used in combination with safer sex counseling and condoms.

Volunteers will be carefully monitored until the end of the study period (approximately June of 2010) and for 6 months afterward.  In addition to the possible usefulness of tenofovir/emtricitabine in HIV prevention, the study will also assess the effects of taking a daily pill on HIV risk behaviors; adherence to and acceptability of the regimen; and whether use of the drug for prevention causes drug resistance in volunteers who become infected with HIV.  Volunteers will be monitored monthly for any possible side effects or abnormalities, and the study drug will be promptly discontinued if any serious concerns are identified.  Any volunteer who becomes infected in the study, despite extensive safer sex counseling and the availability of condoms, receives full medical care including treatment for HIV infection if needed.

Tenofovir/emtricitabine was selected for the iPrEx study because it has been shown to be a safe and effective treatment for HIV, with few side effects in studies involving more than 15,000 people worldwide. Tenofovir, one of the component drugs of tenofovir/ emtricitabine, was approved by the U.S. Food and Drug Administration in 2002.  The tenofovir plus emtricitabine combination pill used in this study was approved for use in 2004 in the United States.  More than 100,000 HIV-infected people around the world have now used these drugs.

A trial of tenofovir for HIV prevention completed by Family Health International in West Africa in 2006 confirmed the safety of daily use of tenofovir in HIV uninfected women, and found that the HIV risk behavior of volunteers declined during the study, likely because of the counseling provided.

HIV Prevention Commitment in Peru, Ecuador the United States, South Africa, Brazil and Thailand

Investigators in Peru, Ecuador, the United States, South Africa, Brazil and Thailand have an outstanding record of conducting HIV prevention research and have demonstrated outstanding compliance with international clinical trial standards.

A key reason for conducting this study in men who have sex with men is the impact the results might have in this population. Studies indicate that prevalence of HIV infection in MSM is between10 and 28% in the cities where the study is being implemented, underscoring the need to conduct HIV prevention research in the communities in which new prevention tools are needed most.

Consultation with and the participation of affected communities in these countries has been a cornerstone in the development and conduct of the iPrEx study. Researchers consult regularly and on all aspects of the study with the Community Advisory Boards (CAB) comprising leaders of AIDS service organizations, community activists, and members of at-risk communities. CAB members have participated in developing the study design, informed consent process, and study recruitment strategies; as well as in educating the community about the trial. Finally, the study investigators have consulted widely and on an ongoing basis with community leaders and government officials to ensure that iPrEx is responsive to the needs of people who are at risk of contracting HIV.

Partners

NIH is sponsoring the iPrEx study through a grant to the J. David Gladstone Institutes, a non-profit independent research organization affiliated with the University of California, San Francisco. Additional funding is provided by the Bill & Melinda Gates Foundation.  The study is being conducted at Investigaciones Médicas en Salud (INMENSA) and Asociación Civil Impacta Salud y Educación (IMPACTA) in Lima, the Asociación Civil Selva Amazónica in Iquitos, all of them in Peru; the Fundación Ecuatoriana Equidad in Guayaquil, Ecuador; Fenway Health in Boston, the San Francisco Department of Public Health in the  United States, the Desmond Tutu HIV Foundation-University of Cape Town, Cape Town, South Africa, the Instituto de Pesquesa Clinica Evandro Chagas – Fundacao Oswaldo Cruz, Rio de Janeiro, Projeto Praça Onze, Universidade Federal de Rio de Janeiro and the Universidade de Sao Paulo all three in Brazil and Research Institute for Health Sciences, University of Chiang Mail, Chiang Mai, Thailand.  Local governments and the U.S. Centers for Disease Control and Prevention (CDC), the United States Agency for International Development (USAID), the Bill  & Melinda Gates Foundation and the International AIDS Vaccine Initiative (IAVI) are currently supporting other studies of HIV PrEP among men who have sex with men (MSM) in the United States, in heterosexual men and women in Africa, and in intravenous drug users in Thailand. 

Data from the Global iPrEx study are expected to be available by the end of 2010.

For questions, please contact iprex@gladstone.ucsf.edu