Starting in July 2010, encouraging results from a number of HIV prevention studies have revolutionized the HIV prevention landscape over this past year – from using oral PrEP and microbicides among HIV-negative people to reduce the risk of infection, to providing early antiretroviral treatment to people with HIV to reduce the risk of transmitting the infection to their uninfected partners.
Here is a quick look at six of the most significant trials: CAPRISA 004, iPrEx, FEM-PrEP, HPTN 052, Partners, and TDF2 that, together, are radically changing the way we look at prevention.
July 2010: CAPRISA 004 – a microbicide study
Background: Conducted by the Centre for the AIDS Programme of Research in South Africa (CAPRISA), Family Health International (FHI), and CONRAD. Funded by the United States Agency for International Development (USAID) and Technology Innovation Agency (TIA).
Who: 889 sexually active women.
Where: South Africa.
What: 1% tenofovir vaginal gel, applied within 12 hours before and after sexual intercourse.
Key results: The microbicide provided 39% protection from HIV acquisition. In women who used the gel more than 80% of the time, there was 54% efficacy. The gel also halved the women’s risk of acquiring HSV-2, the virus that causes genital herpes and also increases the risk of contracting HIV.
November 2010: iPrEx – a large-scale, Phase III PrEP study
Background:Funded by the U.S. National Institutes of Health (NIH) through a grant to the J. David Gladstone Institutes, a non-profit independent research organization affiliated with the University of California at San Francisco (UCSF). Additional funding provided by the Bill & Melinda Gates Foundation.
Who: 2,499 men who have sex with men and transgender women who have sex with men.
Where: Peru, Ecuador, South Africa, Brazil, Thailand and the US.
What: Once-daily does of Truvada (oral FTC-TDF – emtricitabine and tenofovirdisoproxilfumarate), as well as monthly HIV testing and risk-reduction counseling.
Key results: PrEP provided 42-44% protection from HIV acquisition. The protective effect was even higher among those with good pill adherence. According to the initial findings, with 50% adherence reported, the efficacy was 50%; with 90% adherence reported, there was 73% efficacy. Updated findings were presented at the International AIDS Society conference in Rome: the drug had 92% efficacious in preventing HIV infection amongst those who had detectable drug levels; overall efficacy was 42%.
April 2011: FEM-PrEP – a Phase III PrEP study
Background: Implemented by Family Health International (FHI) in partnership with research centers in Africa. Funded by the United States Agency for International Development (USAID), with early funding from the Bill & Melinda Gates Foundation.
Who: 1,951 sexually active women.
Where: Kenya, South Africa, and Tanzania.
What: Once-daily does of Truvada (oral FTC-TDF – emtricitabine and tenofovirdisoproxilfumarate), as well as HIV testing and counseling.
Key results: The interim FEM‐PrEP study results were inconclusive. As determined by a preliminary data review, the study would not have been able to demonstrate whether or not Truvada was effective in preventing HIV in women in this study. FHI, therefore, decided to close the trial early due to futility.
May 2011: HPTN 052 – a Phase III antiretroviral study
Background:Conducted by the HIV Prevention Trials Network (HPTN). Funded by the National Institute for Allergy and Infectious Diseases (NIAID) at the US National Institutes of Health (NIH). Additional support provided by the NIAID-funded Adult Clinical Trials Group.
Who: 1,763HIV serodiscordant couples, in which the HIV-infected partner had a CD4+ cell count of 350-550 cells/mm^3.
Where: Botswana, Brazil, India, Kenya, Malawi, South Africa, Thailand, United States and Zimbabwe.
What: Initiation of early antiretroviral treatment, as well as regular counseling.
Key results:The interim review showed that antiretroviral treatment reduced the risk of HIV transmission from treated partner to uninfected partner by 96%.
July 2011: Partners – a Phase III PrEP study
Background: Funded by the Bill & Melinda Gates Foundation. The University of Washington International Clinical Research Center is the study sponsor and coordinated the trial in collaboration with investigators at the study sites.
Who: 4,758 heterosexual African HIV serodiscordant couples, that is, in which one partner had HIV and the other did not.
Where: Kenya and Uganda.
What: Once-daily does of Truvada (oral FTC-TDF – emtricitabine and tenofovirdisoproxilfumarate) or tenofovir (oral TDF), as well as HIV testing and counseling.
Key results: The risk of infection was reduced by 73% in those who received Truvada, and by 62% in those who received tenofovir alone. Adherence was extremely high: more than 97% of doses dispensed were taken, and 95% of participants stayed in the study.
July 2011: TDF2 – a PrEP study
Background: Conducted by BOTUSA, a partnership between the Botswana Ministry of Health and the US Centers for Disease Control and Prevention.
Who: 1,200 sexually active men and women.
Where: Botswana.
What: Once-daily does of Truvada (oral FTC-TDF – emtricitabine and tenofovirdisoproxilfumarate), as well as HIV testing and counseling.
Key results: In the primary analysis, it was seen that Truvada reduced the risk of infection by 63%. In the secondary analysis, excluding infections that occurred amongst people who had run out of their Truvada pills and had not taken one for at least 30 days, there was 78% efficacy.
[Content that is linked from other sources is for informational purposes and should not construe a Mapping Pathways position.]
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