Key Study to Assess Effectiveness of PrEP to Prevent HIV in Women Stopping Early Due to Futility

Inconclusive Results Underscore Urgency of Ongoing and Additional Research

Statement from Dr. Zeda Rosenberg, CEO, International Partnership for Microbicides

SILVER SPRING, Md. (April 18, 2011) – FHI today announced interim results for FEM-PrEP, a clinical trial of the safety and effectiveness of oral pre-exposure prophylaxis (PrEP) for prevention of HIV infection in women. The Phase III, double-blind, randomized clinical trial has been studying the effects of the antiretroviral (ARV) drug Truvada® – a single, once-a-day pill that combines the antiretroviral drugs emtricitabine and tenofovir disoproxil fumarate – as compared to a placebo pill. 

As Truvada® is already used as a treatment for HIV-positive individuals, it has been considered a promising drug for use in oral PrEP among adults who are HIV-negative but who may be considered high-risk for acquiring the virus. FEM-PrEP is the first large-scale PrEP trial to report findings about the effectiveness of Truvada® in preventing HIV infection from sexual transmission in women.

The interim findings announced today are the result of an Independent Data Monitoring Committee (IDMC) review of FEM-PrEP data from the time the first participant enrolled in 2009 through February 18, 2011. Of the 56 women who became HIV positive while enrolled in the FEM-PrEP study, the IDMC found 28 HIV infections in the active arm where women were receiving a single pill containing oral Truvada® to be taken once a day, and the same number of HIV infections, 28, in the placebo arm where no drug was being taken. As a result of this disappointing finding, the IDMC recommended that the study not continue since it is highly unlikely to be able to demonstrate the effectiveness of Truvada® in preventing HIV infection in the study population. The IDMC did not identify any significant safety concerns.

FEM-PrEP has been led by FHI and co-funded by the US Agency for International Development and the Bill & Melinda Gates Foundation, two organizations at the forefront of HIV prevention research. Gilead Sciences, Inc., provided the drug Truvada® free of charge. FEM-PrEP had been initiated at four sites in three African countries, including Bondo, Kenya; Arusha, Tanzania; and Pretoria and Bloemfontein, South Africa. An estimated 3,900 high-risk, HIV-negative women between the ages of 18 and 35 were expected to enroll in the trial. At the time of the IDMC analysis, the study was more than 50 percent enrolled, with 1,951 women participating.

The interim results from FEM-PrEP announced today were unexpected given the results of iPrEx, the Pre-Exposure Prophylaxis Initiative, which was the first PrEP clinical trial to demonstrate proof of concept. The iPrEx trial, conducted among men who have sex with men (MSM), showed that taking Truvada® once a day along with comprehensive HIV prevention services led to a 42 percent reduced risk of becoming infected with HIV-1 within the study population. iPrEx enrolled 2,499 participants in Peru, Ecuador, Brazil, South Africa, Thailand, and the United States. Several other large-scale PrEP trials are studying the effectiveness of oral Truvada® and/or oral tenofovir in preventing HIV infection among a diverse array of populations and from multiple routes of transmission. FEM-PrEP, as well as the ongoing VOICE study conducted by the Microbicide Trials Network, was among the first to test oral PrEP among women. Other trials are investigating PrEP among injection drug users (CDC 4370 in Thailand) and HIV serodiscordant heterosexual couples (Partners PrEP in Africa).

In addition to the PrEP finding for MSM, there is proof of concept that an ARV-based vaginal microbicide containing tenofovir gel, an ARV, reduces the risk of HIV transmission in women. Microbicides differ from PrEP in that the ARV is delivered vaginally to prevent HIV transmission to women during sex. In July 2010, in an important milestone for HIV prevention, the CAPRISA 004 study found a 39 percent reduced risk of HIV infection in women using tenofovir gel. Currently, the field is awaiting confirmation of the results seen in CAPRISA 004 from two other studies, VOICE (ongoing), which is simultaneously testing the safety and effectiveness of once-daily tenofovir gel, oral tenofovir and oral Truvada®; and FACTS 001 (planned to start in 2011).

The International Partnership for Microbicides (IPM) is one of several organizations working to harness the promise of ARV drugs to develop new tools to prevent HIV infection in women. The FEM-PrEP study was conducted with these same goals, and IPM applauds the research partners and funders involved for their unwavering commitment to this effort. We specifically commend the work and dedication of the principal investigators and the research teams at FHI and in Kenya, Tanzania, and South Africa. Above all, we express our gratitude to the women in Bondo, Arusha, Pretoria, and Bloemfontein who participated in FEM-PrEP and volunteered their time to contribute to the advancement of HIV prevention research.

The research that has gone into FEM-PrEP will be invaluable to informing and advancing the ARV-based HIV prevention research agenda that lies ahead. Researchers and other stakeholders will be carefully reviewing the data generated from FEM-PrEP to help explain why the study could not determine whether Truvada® works to prevent HIV infection in women.

This information will help the prevention community determine how best to develop new HIV prevention tools so desperately needed by women around the world. AIDS is now the leading killer of women between the ages of 15 and 44 globally, with more than 3,000 women infected every day. We must build on the breakthroughs that have been accomplished thus far, and provide women new products to help reverse the course of this devastating epidemic.

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More information about FEM-PrEP is available at: www.fhi.org or via Matt Matassa, mmatassa@fhi.org, 202.341.6519.

About IPM: IPM is a nonprofit organization dedicated to developing new HIV prevention technologies and making them available to women in developing countries. IPM has offices in the United States, South Africa and Belgium. To learn more, please visit www.IPMglobal.org.

Contacts:

IPM US and Europe: Pam Norick, pnorick@ipmglobal.org, +1 301.608.2221 or +1 301.332.3639 (cell) and Brad Tytel, +1 917.414.3691

IPM Africa: Leonard Solai, lsolai@ipmglobal.org, +27.84.660.6776