Topical Gel Shows Promise in Protecting Women Against HIV

AIDS, which initially began as a “small outbreak” of a rare form of cancer among young gay men in California and New York in 1981, has become one of the most destructive pandemics in world history, claiming more than 25 million lives worldwide. During the 1990s, we saw several breakthroughs in AIDS research and the development of new drugs aimed at combating the disease, but still today, none can eradicate the HIV virus, which causes AIDS, from the body. The same disappointment has been seen in the search for a treatment to protect against the spread of the HIV virus. But the years of frustration may not have been in vain as researchers say they may finally have a “promising candidate.”

In a clinical trial of 3,099 HIV-uninfected women conducted between February 2005 and September 2008 in Malawi, South Africa, Zambia, Zimbabwe and the United States, PRO 2000, a gel made by Massachusetts-based Indevus Pharmaceuticals, reduced the rate of HIV infection in women by 30 percent, compared to those using no gel or an unmedicated product. Another microbicide, BufferGel made by ReProtect Inc., was also tested, but showed no significant effect on HIV transmission. During the course of the study, 194 infections occurred; 36 among women using Pro2000 gel, 54 among women using the BufferGel, 51 among those using the placebo gel, and 53 among those who used no gel.

The study was specifically designed to show the gels were safe; an especially important factor considering other studies have shown would-be microbicides actually raised the risk of infection. “For the first time since the epidemic we are seeing something that would provide an option for women to prevent infection,” principal investigator Professor Gita Ramjee told journalists.

The finding was presented at the 16th Conference on Retroviruses and Opportunistic Infections in Montreal. “Although more data are needed to conclusively determine whether PRO 2000 protects women from HIV infection, the results of this study are encouraging,” said Anthony S. Fauci, M.D., Director of the National Institute of Allergy and Infectious Diseases (NIAID), which funded the study. “An effective microbicide would be a valuable tool that women could use to protect themselves against HIV and one that could substantially reduce the number of new HIV infections worldwide.”

According to the NIAID, most new cases of HIV are spread through sexual intercourse or contact with infected blood or tissue. Condoms can block contact with infected semen, vaginal fluid and blood, but many people don’t use them consistently. In cases where partners can’t or won’t use a condom, the ideal preventative treatment would be a microbicide gel, cream, or foam that could be applied topically inside the vagina or rectum.

Salim Abdool Karim, a Columbia University researcher who presented the study results and pro vice-chancellor of the University of KwaZulu Natal in South Africa, said that microbicides are key to preventing HIV in African women who are often infected by their husbands or steady sexual partners. “I have nothing to offer a woman who asks me how to prevent HIV,” he said. “I can’t tell her to be faithful, because she is. I can’t tell her to be abstinent or use condoms, because she wants to have her husband’s children.”

A separate study sponsored by the London- based Medical Research Council and the Department for International Development of the United Kingdom is currently conducting a larger study of PRO 2000. Their Phase III study includes almost 9,400 women and is set to conclude in August 2009.

Other research presented at the conference suggests that Gilead’s Viread and Truvada, in gel or oral pill form, might also prevent the spread of HIV. One test measured how oral Truvada would affect monkeys exposed to SHIV, an animal version of the AIDS virus, through the rectum. Although most untreated monkeys were quickly infected after being exposed to the virus twice, two doses of Truvada, one before and another after rectal exposure, protected most monkeys from infection, said Dr. Gerardo Garcia-Lerma, a senior scientist in the Centers for Disease Control and Prevention (CDC) HIV/AIDS division.

In another test, Drs. Charles Dobard and Walid Heneine of the CDC treated monkeys with one of two gels, one containing Viread alone and one with both drugs. They found the gels to work equally well in protecting the monkeys from SHIV. “This is very promising, although we’re waiting for the results of human trials to see if they correlate with animal studies,” Heneine said in an interview. Currently, at least seven human studies are looking at whether giving high-risk people oral doses of Gilead’s Viread or Truvada can safely prevent transmission.

According to the CDC, between 1 and 1.2 million Americans are living with HIV infection or AIDS, and about one-fourth of them do not know they have it. Approximately 56,300 new HIV infections occurred in the United States in 2006. In San Francisco, 800 to 1,000 new infections occur annually, a number that has held fairly steady for a decade. In an effort to reduce the number of new HIV cases, San Francisco is launching a new two-year-pilot project designed to catch new HIV infections during the two- or three-month period after infection, or the acute phase, when the viral load is highest. “The virus gets in your body and starts to replicate at a very high rate before the natural immune responses of your body start to mobilize,” said Mark Cloutier, chief executive of the San Francisco AIDS Foundation.

Anyone reported to have engaged in recent, high-risk behavior will be able to take viral RNA (ribonucleic acid) testing, which will identify those who are acutely infected. The expanded testing, along with counseling, will take place at Magnet, a community health center for gay men in the Castro. Those awaiting results, which take about two weeks, will be encouraged to alert their partners and to behave prudently, as if they were HIV-positive, said Steve Gibson, director of Magnet. “The same behavior that led to people getting infected can lead to them unknowingly infecting someone else when they have a high viral load,” Gibson said. “We’ve been talking about the San Francisco model of AIDS care for 25 years. We’re still trying things first here—we’re using technology to find out who is at greatest risk.”

Testing is expected to be expanded to other locations in the city, including the Tenderloin. One of the goals is to reach a segment of the population that has been difficult to reach. “We’re hoping to identify African American men who are having sex with other men,” said Cloutier. “The house is on fire for African American men who have sex with other men.” A report in September by the CDC revealed that a number of new infections in black gay and bisexual men 13 to 29 years old are approximately twice that of white or Latino gay men in the same age group.

The AIDS Foundation is also funding a new program to raise awareness about acute infections among transgender women. In San Francisco, the HIV incidence in that group is almost 25 percent.