New microbicides
to stop HIV in its tracks

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Scientists in the European Microbicides Project (EMPRO) are developing novel anti-HIV microbicides which will one day form a vital weapon in our arsenal against this devastating disease.

The initiative, which is the largest microbicides project in the world, brings together 27 partners in 11 countries, including 8 EU Member States, as well as Switzerland and 2 African nations. They include universities, research institutes, hospitals, pharmaceutical companies and small and medium-sized enterprises (SMEs) with expertise in molecular structure, the mechanisms of HIV infection, microbicide production and clinical testing.

Microbicides have an important role to play in preventing the spread of HIV. Because they can be used by women without the knowledge of her partner, microbicides empower women to take control of their own sexual health in situations where women are unable to force their partners to use a condom.

One product created by the project is already being tested in clinical trials, and the partners hope to have affordable microbicides, developed within EMPRO, on the market by 2012.

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A global problem

According to the World Health Organization (WHO), in 2007 there were 33 million people around the world living with HIV. In the same year, 2.5 million people were newly infected with HIV, and 2 million people died of AIDS.

Sub-Saharan Africa bears a disproportionate share of the world’s HIV burden; the region is home to 22.5 million HIV positive people (over two thirds of the global total), and AIDS is the leading cause of death there. Meanwhile, a number of Asian countries are also in the grip of HIV epidemics.

Antiretroviral drugs are helping to prolong the lives of many HIV sufferers. Yet these drugs do not completely eliminate HIV, and the high costs of antiretrovirals place them beyond the reach of most patients
in the developing world.

Prevention is better than cure

While the hunt goes on for a cure for HIV, many researchers are focusing their efforts on ways to prevent the virus from being transmitted from one person to another in the first place.

According to the Joint United Nations Programme on HIV/AIDS (UNAIDS), 90 % of cases of HIV are caught through sexual contact. Many campaigns designed to stop the sexual transmission of HIV use the ABC (‘Abstain, Be faithful, Use condoms’) approach. While useful, the ABC method is not without limitations.

In some areas of the world, abstinence is not an option for women who have no choice but to marry at an early age to survive. Fidelity is also no guarantee of protection: many women catch HIV from their husbands or long-term partners. Condoms are extremely effective at preventing HIV transmission, but many women are simply not empowered to force their partners to use them.

A good deal of effort is being invested in the hunt for an AIDS vaccine, although the tricky nature of the HIV virus means that an effective vaccine is still some way off.

Microbicides represent another potential tool which could stop HIV transmission through sexual contact. As yet, there is no effective microbicide on the market. Nevertheless, the potential impact of a good microbicide is immense. Studies carried out by the London School of Hygiene and Tropical Medicine suggest that even a microbicide that is only 60 % effective could still prevent 2.5 million cases of HIV over 3 years, if just 20 % of people in contact with local services in developing countries used it half the time.

Microbicides – empowering women

Microbicides are creams or gels that are applied to the vagina before sex to protect the woman against HIV and other sexually transmitted diseases. Because women can use them without the knowledge or consent of their partner, microbicides empower women to protect themselves against HIV.

Microbicides work in a number of ways. They form a physical barrier between the virus and the cells lining the vagina. They can also damage the outer layers of the virus, prevent it from replicating, or stop it from binding to target cells. They can also be applied anally, to provide protection for men who have sex with men, as well as women who engage in anal sex.

EMPRO – delivering novel microbicides

EMPRO is investigating novel microbicides in the laboratory and taking the most promising drug candidates through the drug development process to the early stages of clinical testing.

One area under investigation is glyconanoparticle technology. Glyconanoparticles are nanoparticles that can mimic the carbohydrate structures found on the cell surface. They can block the carbohydrate-protein interactions which promote infection.

The project is also looking at the possibility of using small fragments of antibodies that can block the virus. These can be produced more efficiently and cheaply than conventional antibodies.

The best microbicide candidates are selected on the basis of scientific results from the laboratory plus a number of other criteria, such as the safety and efficacy of the drug, how easy it is to manufacture, how long it will take to develop, how much it will cost, what regulatory hurdles there might be, and whether it could generate drug-resistant HIV.

The project partners have already succeeded in taking three monoclonal antibodies to the clinical trial stage. The aim of this study is simply to see how the drugs, which have been formulated into a gel, behave in the human body, to establish the safe dose, and to find out if the drug causes any side effects.

Millions of lives saved

Despite extensive research efforts, there is still no effective microbicide on the market with which women can protect themselves. By getting a potential microbicide to the clinical trial stage, EMPRO has started to achieve its goals and also established itself as a leader in the field. The new microbicides coming out of the EMPRO project could therefore help to save millions of lives around the world.