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Two Major Studies Prove HIV Pre-Exposure Prophylaxis (PrEP) Works in in Heterosexual Women and Men; Build on iPrEx Data Showing PrEP Reduces HIV Infections in Men Who Have Sex with Men
  The following statement was released by iPrEx Protocol Chair Robert Grant, MD, MPH
of the Gladstone Institutes and the University of California at San Francisco

For immediate release 13 July 2011
contact: Mark Aurigemma 1-646-270-9451;
Pedro Goicochea 1-415-490-8350;

"Today's news from the Partners PrEP and CDC Botswana (TDF2) studies detailing the safety and effectiveness of PrEP in heterosexual women and men is a major step forward in HIV prevention research with global implications for helping to end the AIDS epidemic.

PrEP involves uninfected people taking antiretroviral medications, which are usually used to treat HIV, to reduce their chances of HIV infection. With 2.6 million people worldwide newly infected by HIV each year, the compelling evidence presented by the iPrEx, Partners PrEP and TDF 2 studies -- that PrEP greatly reduces the risk of HIV infection both in heterosexual men and women and among men who have sex with men -- makes it increasingly clear that PrEP can play an important role in helping to slow the global epidemic in multiple populations at risk.

Partners PrEP and TDF2 are the are the third and fourth studies in 12 months to demonstrate that oral or topical PrEP reduces HIV infections significantly. In November 2010, results from the Global iPrEx study ( showed robust and highly statistically significant evidence that daily PrEP using the emtricitabine/ tenofovir combination tablet known commercially as Truvada reduced HIV infection risk among men who have sex with men (MSM) by an average of 44% overall, and by 90% among those who used PrEP consistently enough to have detectable drug in the body. An update on the iPrEx study to be presented at the 6th IAS Conference on HIV Pathogenesis, Treatment and Prevention in Rome next week demonstrates that the prevention impact of PrEP is consistent over time and across study subgroups.

In July, 2010 the CAPRISA 004 study showed that a topical form of PrEP using tenofovir gel, also known as a microbicide, safely reduced HIV infections in heterosexual women. Follow-up research is underway to determine why one other study, FEM-PrEP, was not able to demonstrate PrEP's effectiveness. The scientific evidence for PrEP is clearly mounting, however, as four out of five large-scale clinicaltrials of PrEP have shown a strong HIV prevention benefit.

On all fronts there are new, highly effective approaches for prevention, including oral PrEP for MSM and heterosexual men and women, clean needles for injecting drug users, male circumcision for heterosexual men, vaginal gels for heterosexual women, early treatment for discordant couples and suppressive therapy for pregnant women. These new opportunities demonstrate that we can win the war on HIV, if we act now. PrEP presents a unique HIV prevention advantage because it can help stop the cycle of infections from people who are newly infected with HIV but unaware of their status. Making PrEP available is also an important strategy to draw people in to HIV testing and help HIV-negative people remain negative.

Recently, iPrEx launched a 72-week open-label extension of the study, called iPrEx OLE ( at eleven sites in six countries. iPrEx OLE will provide Truvada PrEP to any HIV-uninfected participants from the original iPrEx study. No placebo will be used in iPrEx OLE. Approximately 2,000 MSM are expected to participate in the open-label extension, which will gather important additional information on longer-term PrEP safety, efficacy and adherence. Additional studies of oral and topical PrEP now underway include the VOICE trial in Africa and a CDC study of PrEP in injecting drug users in Thailand.

The iPrEx study congratulates the 1200 women and men who participated in TDF2 and the more than 4700 couples who participated in the Partners PrEP study, as well as the study organizers and implementers, for their outstanding contribution to our understanding of PrEP and for taking us another important step forward toward a world in which the HIV epidemic can end."


Two studies show that drugs used to treat AIDS can be used to prevent HIV infection, too

By David Brown, Updated: Wednesday, July 13, 5:01 AM

Two new studies done in three African countries have shown for the first time that AIDS drugs taken daily can cut by more than half a person's chance of becoming infected with HIV through heterosexual intercourse.

The results, announced early Wednesday, provide more evidence that the drugs responsible for saving the lives of millions of HIV-infected people over the last 15 years may also be the most useful tool for preventing new infections.

In the last 12 months, other research has shown that antiretroviral drugs in either pills or vaginal gels can help prevent infection in specific groups - women, male homosexuals and people whose regular sex partners are HIV-positive. The new studies show the strategy also works in the broad population of heterosexual men and women in Africa, the group by far most affected by the 30-year-old pandemic.

The standard treatment of HIV infection is three or more antiretroviral drugs taken daily for life once the virus has begun to measurably damage the immune system. When used for "pre-exposure prophylaxis" (PrEP) one or two drugs are taken daily.

One of the new studies, conducted in Kenya and Uganda, was stopped a year and a half early because the results were so dramatic. The other, run in Botswana, ended on schedule in the spring. Researchers planned to describe its results at a meeting in Rome next week but moved the announcement up.

The news adds urgency to efforts to provide vast quantities of antiretroviral drugs to the developing world. Today, 6.6 million people there are taking the medicines for infections they have. Someday, a greater number may take them to avert infection. Worldwide, about 34 million people are living with HIV. Two-thirds are in sub-Saharan Africa.

"These results are fundamentally important for HIV prevention, especially in Africa," said Jared Baeten, a physician at the University of Washington who co-directed the study in Kenya and Uganda.

"Our biggest challenge now is how do we move from research to getting things out to the general public where they're most needed," said Lynn Paxton, an epidemiologist at the Centers for Disease Control and Prevention who led the Botswana study.

In the University of Washington study, called "Partners PrEP," 4,758 couples were recruited from nine locations starting in July 2008. In each couple one person was infected with HIV and the other wasn't.

The uninfected partners were randomly assigned to take a drug called tenofovir; or tenofovir and and another drug, emtricitabine, which is a combination sold under the trade name Truvada; or placebo. Everyone was counseled on how to avoid infection and was provided condoms.

Through the end of May there'd been 47 infections in people assigned placebo, but only 18 in those taking tenofovir (a 62 percent reduction) and 13 in those taking Truvada (73 percent fewer).

Both women and men were equally protected. The rate of serious side effects was similar in the three arms of the study, although the researchers did not provide details about complications in their announcement.

In the Botswana study, 1,219 men and women were enrolled and assigned to take either Truvada or placebo. Nine taking Truvada became infected compared to 24 taking placebo-a 63 percent reduction in those on the active drug. People taking Truvada had a greater frequency of side effects such as nausea and dizziness.

While the results of the two studies were similar, they differed greatly from one called FEM-PrEP reported earlier this year. In it, 2,000 women in Kenya, Zimbabwe and South Africa took Truvada or placebo, and Truvada provided no protection. The researchers are trying to figure out why.

Baeten believes a big reason his experiment showed promising results is that the subjects took their pills 97 percent of the time. (In the CDC study in Botswana, people took them 84 percent of the time). He speculated that FEM-PrEP failed to show protection because its participants simply skipped too many doses.

"I think adherence is the biggest driver of the difference between our study and theirs," he said.

TheBotswana study cost $31 million, all paid by the U.S. government. The study in Kenya and Uganda had a budget of $63 million provided by the Bill and Melinda Gates Foundation, but all that money was not used because the experiment closed early.

The drugs used in the studies are made by the California biotech company, Gilead Sciences, which donated them for the research.

Last week, Gilead signed an agreement with a Geneva-based organization called the Medicines Patent Pool that will allow generic pharmaceutical companies in India to make cheap versions of tenofovir and emtricitabine for use in 111 low- and middle-income countries even though the drug is still covered by patents in the United States.

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