New Science, New Hope: Microbicides and HIV prevention

By Bobby Ramakant, CNS
November 30, 2010
The author serves as CNS Policy Adviser and is a World Health Organization (WHO) Director-General’s WNTD Awardee 2008. He writes extensively on health and development through Citizen News Service (CNS). Email: bobby@citizen-news.org, website: www.citizen-news.org

At the forthcoming Biennial Conference of the Irish Forum for Global Health (IFGH) in Maynooth, Ireland, one of the two keynote guest lectures - The John Kevany Memorial lecture - will be delivered by Dr Zeda Rosenberg, Chief Executive Officer (CEO) of the International Partnership for Microbicides (IPM) on "New Science, New Hope: Giving Women Power over HIV/AIDS." The microbicides refer to a new type of product being developed that people could use vaginally or rectally to protect themselves from HIV and possibly other sexually transmitted infections.

One of the defining moments in microbicides advocacy was in July 2010 at the XVIII International AIDS Conference (IAC) in Vienna, Austria where successful results of the much awaited tenofovir microbicides clinical trials (CAPRISA 004) were announced: women who used the tenofovir microbicide gel were far less likely to become infected with HIV than women using a placebo gel. The tenofovir microbicide gel users were 39 percent less likely, overall, to become infected with HIV than women who received a placebo gel. More importantly, underlining the significance of adherence and counselling in clinical trials, women who used the tenofovir microbicide gel correctly more than 80 percent of the time, HIV infection was 54 percent less likely. Also as many advocates of new HIV prevention technologies demand – these tenofovir microbicide also showed activity against genital herpes (a sexually transmitted infection), reducing its incidence by half.

Let me put a word of caution here: this is undoubtedly welcome news, but research is not over yet. There is still a long way to go which may span over years through rigorous path of clinical trials and product development, before any microbicide can truly be available to communities.

One of the big debates around using anti-retroviral (ARV) based microbicides to prevent HIV transmission is that tenofovir is also used by people living with HIV (PLHIV) for their ARV therapy. PLHIV take oral version of tenofovir in ARVs like Viread, Truvada and Atripla.

So the worry is: will using this ARV based microbicide (tenofovir in this case) make people resistant to tenofovir and thereby negate the positive outcomes of ARV based therapy later in their lives in case they become infected with HIV and require the ARV treatment?

"There is now evidence to indicate that ARVs can prevent HIV as well as some of the non-HIV STIs. The major challenge facing the Microbicides Society of India (MSI) as well as other partner research agencies globally, would be to make a combination of different ARVs, so that these products become more effective, safer and user friendly for preventing the HIV and some of the non-HIV STIs as well as reproductive tract infections (RTIs). It would be an icing on the cake, if few of these microbicidal products could also provide the contraceptive protection concurrently to the users of these products" said Dr Badri N Saxena, President, Microbicides Society of India (MSI), who is a globally acclaimed researcher and an inspiring advocate for new HIV and reproductive health technologies.

"One reason for engaging ARV drugs into microbicides development is to accelerate the candidates that are ready to go into clinical trials because they come from a very rich product development profile. So now we have so many good candidates, can we provide the much needed bridge to establish biological plausibility - to find out will these things actually work in clinical trials" said Prof Robin Shattock to this correspondent at the International Microbicides Conference in Pittsburgh, USA (May 2010).

Also at the International Microbicides Conference earlier this year, two key studies were presented - one study involving a mathematical model and the other assays of cells and tissue, and both these studies arrived at the same answer to the worrying question whether drug resistance could be a problem if ARV drugs become a mainstay for HIV prevention. Resistance could happen, if people, who are unknowingly already infected with HIV, use the approach. So in other words, if HIV negative people use ARV based microbicides the risk of developing resistance is not there, but if they are already HIV positive and unaware of their status, the risk of resistance is there. These two studies underscore the importance of incorporating routine HIV testing and ongoing monitoring of infection status in any prevention program that involves the use of ARVs.

Probably the forthcoming Irish Forum for Global Health (IFGH) biennial conference might offer some answers to these concerns and give a major thrust to research and eventual development of new HIV prevention technologies. We will post the audio recording of Dr Zeda Rosenberg's lecture at Irish Forum for Global Health (IFGH) biennial conference on www.citizen-news.org! Stay tuned!

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Posted on: November 30, 2010 09:30 AM IST