Kingsley Obom-Egbulem, New Delhi
Mr. Kapil Sibal, the Indian Minister for Science and Technology and Earth Sciences had thought that his audience at the closing ceremony of the 5th Microbicides Conference in New Delhi, India may include some people already losing patients at the slow progress being made towards finding a safe and effective microbicide.
So, he probably took a quick lesson on how to motivate and encourage despaired microbicides researchers, advocates, funders and of course trails participants.
People don’t understand what research is all about, Sibal said. Research is simply the validation of hypothesis. You have to make it clear to funders that research is a long term effort and success is built on failure.
It is not too certain how well the octogenarian’s motivational speech was received especially by delegates who felt the quest for microbicides has dragged on for too long, but it gave some others enough reasons to count their blessings.
Dr. Peter Piot the UNAIDS Executive Director had earlier exprresed optimism that the world is closer to a microbicides than when it first started. I am here today because I believe that one day we will have a microbicides, says Piot.
Who wouldn’t believe him especially after sharing some historical facts and helping everyone to understand that the journey may be long but it is steady and on course.
It took 50 years to develop a polio vaccine. It took 40 years of clinical trials to come up with an effective treatment for pediatric leukemia and we still don’t have truly effective vaccine for tuberculosis or cholera& and the fact that some microbicide trials ran their full course is something to cheer about.
For Piot, even though scientists have nothing to show the world yet as far as safe and effective microbides is considered, they are certainly learning along the way and key among the lessons learnt so far is how not to develop a microbicides.
We are learning a lot of lessons about methodologies and developing new principles around prevention research, he says.
What started in 1992, in form of small but significant streams of funding from the US National Institute of Health(NIH) for minor research work around microbicides has grown into $131 million between 2000 and 2006 this aside from European Funding which has grown from $700,000 to $56million within the same period.
This learning process has seen several products coming up for trials and not making it through.
From Acid Buffers -which maintains an acidic level within the vagina to Adsorption inhibitors -which prevent contact or attachment with target cells,Entry/fusion inhibitors – which prevent virus fusion and entry into target cells to Replication inhibitors which block viral replication.
There are also Surface-active agents (also known as surfactants) which inactivate or destroy viruses or bacteria by disrupting their outer envelopes or membranes.
HIV simultaneously enters two different types of cells in the vaginal epithelium (outer lining of vaginal cells) associated with the immune system — Langerhans cells and CD4+ T-cells.
With most of the candidate microbicides already tried recording some shortcomings which made them either unsafe (even when they had effect on HIV) or not too effective against HIV within the vagina, the search now has gone the direction of ARV-based microbicides .These are microbicides products made from antiretroviral. Since ARVs affects the progress of HIV in the body, it is believed that they can also affect the virus within the vagina area.
The Tenofovir Gel is the most current within this class and series of clinical trials done on the gel seems to have indicated unprecedented hope for the future thus qualifying it for effectiveness trials like drug absorption trial among pregnant women and another trial to evaluate dosing strategy timed around sexual intercourse.
Of course, the concern about ARV drug resistance( if a woman using ARV based microbicides for prevention eventually tests positive) seems to be standing in the way of ARV-based microbicides such as Tenofovir. It is a hurdle researchers are bent on crossing when they get there.
In moving ahead Piot’s counsel for the research community seems indispensable and top among this is the need for more rigour in selecting which products moves to the next stage of clinical trials and the need to avoid offering too much hope where there is none.
I worry that we set ourselves up unnecessarily for failure by over- hyping what we hope to achieve and by not doing enough to explore and share what can be learnt through trials.
Enough lessons learnt already. But what roles these lessons would play in shaping the outcome of the next phase of clinical trials is not any body’s guess.
First published March 7,2008
Leave a comment