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Topical Microbicides

Removing Barriers to HIV Prevention

Spring 2001

A note from TheBody.com: Since this article was written, the HIV pandemic has changed, as has our understanding of HIV/AIDS and its treatment. As a result, parts of this article may be outdated. Please keep this in mind, and be sure to visit other parts of our site for more recent information!

Topical Microbicides: Removing Barriers to HIV Prevention

The Trouble with Condoms

Ask a group of people to word associate the phrase "HIV prevention" and chances are you'll hear a chorus of "condoms!" in return. Thanks to exhaustive safer sex educational campaigns, millions of people know that a properly used condom can successfully impede transmission of HIV and many other sexually transmitted diseases (STDs). Most people also know that infection with other STDs, such as gonorrhea, raises the possibility that a person will become infected with HIV.

Yet millions of people do not use condoms and continue to put themselves at risk every time they have sex. This knowledge/behavior disconnect is reflected in recent increases in infection rates of HIV and other STDs such as syphilis, gonorrhea and chlamydia. A recent estimate of HIV infection in young, gay black men is a startling 30%.

Why, armed with condoms and information, do people continue to put themselves at risk? The reasons are many. Some of them are:

  • Safe sex fatigue. Plainly put, people are tired of constantly being on guard against HIV.

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  • Some people regard condoms as a barrier to sexual pleasure and deep intimacy. Many studies suggest that only 20% of people in a stable relationship use condoms. Even those who use condoms with "outside" partners may be unwilling or unable to use them with a primary partner. One study conducted at Columbia University showed that 43% of men-who-have-sex-with-men (MSM) reported inconsistent condom use.

  • Women (and some men) often don't have control over when and how they have sex. Asking a man to use a condom may result in a woman being beaten, threatened, or abandoned by her partner. The possibility of a violent response is especially high if a man believes that condoms imply a lessening of male pleasure, promiscuity or lack of fidelity, or a woman's "inappropriate" knowledge of sexual practices.

Prevention methods based on condom use, monogamy, and abstinence have failed to keep millions of people from becoming infected with HIV and other sexually transmitted diseases. Each day sees as many as 16,000 new HIV infections globally. There are 34 million people in the world living with HIV/AIDS and 95% of infections occur in developing countries. More than 90% of these HIV infections are transmitted through unprotected sex and at least 5% of those infections are transmitted through anal sex. Adding to this bleak picture, UNAIDS reports (as it has every year for at least the last 5 years) that it will be 10 years or longer before an effective preventative vaccine is ready for use.


Topical Microbicides: New Hope for HIV/STD Prevention

There is no magic bullet solution to stop the spread of HIV and other STDs. Complex issues including poverty, disenfranchisement, and powerlessness defy easy solutions. Meanwhile, people who do not or cannot use condoms need the tools to protect themselves now. As a convenient and practical method of prevention, topical microbicides represent such a tool.


What Is a Microbicide?

A microbicide is any substance that can substantially reduce transmission of sexually transmitted infections, including HIV, when it is applied in the vagina or rectum. A microbicide could be produced as a gel, cream, film, suppository, sponge, vaginal (or rectal) rings or wipes.

Most of the microbicides being developed will probably also have some contraceptive effect -- because it's hard to make something that neutralizes viruses and bacteria but doesn't affect sperm.

Some scientists are also working on products that may be microbicidal without being contraceptive. These will be useful to couples who want to conceive a child while still protecting themselves from infection. Non-contraceptive microbicides may also offer acceptable protection for those who choose not to use contraceptives for religious or cultural reasons.

It is hoped that some of the microbicides approved for distribution will be able to protect against multiple STDs, in addition to HIV.

Two or more of these approaches may be combined with a number of active ingredients to develop a successful microbicide. Right now there are no proven microbicides on the market, although there are at least 60 topical microbicides in development and 23 microbicidal products being tested in people. This is a promising increase compared to the dozen compounds that were being developed in 1994.

Microbicides currently under development work in several different ways:
  • Killing or inactivating STDs: Detergent-like chemicals disrupt cells membranes of bacteria, and cover the surface of viral STDs. Compounds such as nonoxynol-9, octoxynol-9 and benzalkonium chloride, menfegol; and N-docosanol are included in this category.

  • Preventing STDs from entering target cells: These chemicals would prevent infection by blocking the attachment of infecting organism. Products include PC-515, Pro 2000, and Dextran 2 Sulfate.

  • Preventing STDs from replicating: The anti-retroviral agents PMPA gel and nevirapine gel/cream are in this category.

  • Changing the vaginal/rectal environment to increase natural defense mechanisms: Products like BufferGel and Acidform aim to maintain natural levels of acidity in the presence of semen and contain lactobacillus, which naturally resides in the healthy vagina, and which produces hydrogen peroxide to kill HIV and STDs.

  • Invisible condoms: These products would prevent infection by forming a protective barrier after being inserted into the vaginal or rectal canal. One such product is liquid at room temperature and quickly turns into an impermeable gel inside the body.


How Would a Microbicide Be Used?

Topical microbicides could be used for anal or vaginal sex, along with condoms for extra protection, or instead of condoms when condom use isn't possible.

Some have also suggested that a mouthwash-type product would also be useful for protection during oral sex. (The inside of the mouth is made up of the same type of mucosal cells as the vagina, so this isn't as far-fetched as it may seem.)

Microbicides may also help prevent HIV transmission from mother to baby during delivery by reducing the amount of HIV in an HIV-positive woman's vagina right before she gives birth. This might be especially important in very poor countries where women do not have access to anti-HIV therapy.

Because they are not actual physical barriers, microbicides will never be as good at stopping the transmission of STDs as a condom. However, the success of any method of prevention is a function of not only how effective it is, but how often it is correctly used. Because microbicides may be used more consistently than condoms, they may be more effective in the long run.


How Could Microbicides Benefit HIV-Positive Users?

There are several ways that microbicides could be useful to people who are HIV-positive. Since microbicides neutralize disease-causing organisms in both semen and vaginal secretions, they may give HIV-positive users a way of reducing their partner's risk of contracting HIV during sex. A microbicide could also reduce the risk of two HIV-positive partners being reinfected with different strains of HIV. They may also reduce an HIV-positive person's risk of getting other STDs, bladder infections, or yeast infections. For people with compromised immune systems, this could be an important advantage. It is important to note that condoms can also help with these issues.

Some products may be able to help HIV-positive women become pregnant without exposing her partner to HIV.

It might also be possible to develop products that would help an HIV-positive man to conceive a baby sexually, without infecting his partner if she were HIV-negative.


What Other Advantages Are There to Using Microbicides?

It is hoped that microbicides will be inexpensive and available over-the-counter like condoms. Successful use of the condom, however, requires the cooperation of insertive sexual partners; successful microbicide use may not even require their knowledge. Microbicides could also offer increased sexual satisfaction while practicing safer sex. In addition to the lack of physical barriers, other characteristics of microbicides such as smell, taste, and viscosity may afford more choices in sexual pleasure.


Microbicide Research

Interest in developing a form of STD prevention that could be used without a partner's knowledge or consent began in the early 1980s. Many organizations advocating the development of microbicides, including the Alliance for Microbicide Development (AMD) in Takoma Park, Maryland, and Microbicides as an Alternative Solution (MAS) in Berkeley, California, were developed to organize the microbicide movement. Research and interest in microbicides has almost exclusively focused on vaginal use for two reasons. One is that worldwide, women make up the majority of those exposed to HIV. This is often because they do not have prevention methods that they can control. Furthermore, the number of women infected is the fastest-growing group of new HIV infections, and now represents 45% of HIV/AIDS cases worldwide, as compared to only 25% in 1992. In sub-Saharan Africa women represent more than 55% of adults living with HIV.

The second reason is that heterosexism has inhibited a broader discussion of anal sex practices and rectal microbicides. Dr. Connie Celum at the University of Washington is responsible for the only research of rectal microbicides on human subjects. She addresses the anal stigma of science, saying "Most of the researchers in this field aren't just homophobic, they are erotophobic." Slowly, more interest and research has focused on finding a product that can be used both vaginally and rectally, although differences in the anatomy and environment may hinder such a formulation, making it necessary to create different products for vaginal versus anal sex. The open-ended rectal cavity makes it difficult to thoroughly coat and the acidity levels and bacterium ecology differ from those of the vagina. Unfortunately, these considerations are being ignored by many researchers, and funding of rectal microbicides is often being suppressed by conservative activists.

A barrier to microbicide research is lack of public awareness. People cannot demand what they have yet to imagine. By far the largest barrier, however, is lack of funding. Less than 1% of all federal AIDS funding goes towards finding a successful microbicide.

New drug development is usually funded primarily by major pharmaceutical companies that have the money to invest in large clinical trials. Unfortunately, none of the largest corporations are investing in microbicide research. They are reluctant for a variety of reasons. Their main concern, however, is that microbicides may not be profitable enough to justify the cost of developing them. Those who need the product the most are the least able to afford it. According to Alliance for Microbicide Development, it costs about $20 million to get one product from discovery through Phase II trials of safety. It can then cost up to $20 to $30 million more to get it through the huge Phase III efficacy trials, which can involve as many as 3,000 to 4,000 participants per product. Right now, about $35 million per year, at most, is being spent globally on microbicide research. The U.S. government is providing about $26 million of that. Without additional funding, the money just isn't there to move potential microbicides efficiently through the research pipeline. Unless industrialized counties, including the United States, make microbicide research a higher priority, research will be delayed and even more lives will be lost during the wait for effective products. Effective microbicides might transform the HIV epidemic from a raging wildfire to a more controlled burn.

The Global Campaign for Microbicides is a broad-based, world-wide coalition of organizations working to engage individuals, community-based organizations and institutions in the advocacy needed to make microbicides a reality soon.

In addition to generating media coverage, speaking at conferences and lobbying legislatures, Global Campaign is collecting signatures in over 80 countries on a petition for greater investment in microbicides.

The goal is to amass 250,000 signatures calling for increased funding from the U.S. government, the European Union and other public donors. Global Campaign will present the completed petition at the 2002 international AIDS conference.

Global Campaign has also helped Maryland Representative Connie Morella write the Microbicide Development Act. If passed, the Act would increase federal microbicide research funding at the NIH to $50 million in 2001, $75 million in 2002, and $100 million in 2003 -- enough to get the first products through the research pipeline.

More information on microbicide development is available at the Web site http://www.microbicide.org. You can help get safe, effective microbicides onto our drugstore shelves and into the hands of people who need them all around the world. Everyone who supports this issue may call their representatives and senators and ask them to sign on as a co-sponsor of the Microbicide Development Act as soon as it is re-introduced in congress. Congressional contact information is available, by state, on the Web site www.congress.org.


A note from TheBody.com: Since this article was written, the HIV pandemic has changed, as has our understanding of HIV/AIDS and its treatment. As a result, parts of this article may be outdated. Please keep this in mind, and be sure to visit other parts of our site for more recent information!



  
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This article was provided by Seattle Treatment Education Project. It is a part of the publication STEP Perspective.
 
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