Main Category: HIV / AIDS
Also Included In: Sexual Health / STDs
Article Date: 28 Nov 2011 - 8:00 PST
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A tenofovir-containing microbicide vaginal gel aimed at preventing sexual transmission of HIV in females has been dropped from the VOICE trial after a routine study data review concluded that it was not effective, researchers from the Microbicide Trials Network, which is based at the University of Pittsburgh medical school, announced.
The VOICE (Vaginal and Oral Interventions to Control the Epidemic) HIV prevention trial has been testing two HIV medications: The daily administration of two different ARV (antiretroviral) tabletsA vaginal gel containing ARV tenofovirA routine review of data carried out by the National Institute of Allergy and Infectious Diseases (NIAID)'s independent Prevention Trials Data and Safety Monitoring Board (DSMB), surprisingly, found that the gel was ineffective. Researchers could not explain why - the gel seemed to do well in a previous reviews. The review found no safety concerns with either the gel or the oral Truvada tablet (tenofovir and emtricitabine combination). The researchers stressed that testing the effectiveness of Truvada will continue.
The oral tenofovir tablet was discontinued from the trail after a routine DSMB review in September 2011; it was found to be safe, but not more effective than a placebo in preventing HIV in the female participants of the study.
VOICE enrolled 5,029 sexually active females who were HIV-negative at baseline. It is being conducted at 15 sites in Zimbabwe, South Africa and Uganda.
The human study is being carried out by The Microbicide Trials Network, a network of HIV/AIDS clinical trials, funded by NIAID, the Eunice Kennedy Shriver Institute for Child Health and Human Development, as well as the NIMH (National Institute of Mental Health).
The study was divided into five groups, with approximately 1,000 women in each group: The tenofovir gel groupThe inactive placebo gel groupThe oral tenofovir groupThe oral Truvada groupThe inactive placebo tablet groupThe participants had to administer their medication or placebo daily. The aim was to compare the active products against a placebo, as well as determining which treatment the women preferred. This is the only human study to compare both ARV tablets and a vaginal gel simultaneously.
The November 17th DSMB review - the most recent one - looked at data gathered from September 9th, 2009 to September 30th, 2011. After analyzing the data, DSMB recommended that the tenofovir and placebo gel arms be discontinued from VOICE, because tenofovir gel was not statistically significantly better at preventing HIV infection than the placebo gel.
The HIV incidence rates in the two groups were virtually the same: 6.1% in the inactive placebo gel group acquired HIV in a twelve-month period6% in the tenofovir gel group acquired HIV in a twelve-month period The DSMB advised VOICE to discontinue the gel arms of the study and that the participants who had been randomly selected for the two groups discontinue the use of the gels and be exited from the study as soon as feasibly possible.
The Microbicide Trials Network is informing all participants of the latest change to the study. Because there were no major safety issues associated with the tenofovir gels, those randomized to the vaginal gel arms will discontinue using the gel when they come to their next planned clinic visit (December/January).
As normally occurs when participants exit the study, those in the two gel groups will come back to their study clinic two months after they have discontinued the gel treatment for a last set of tests, which will include testing for HIV as well as counseling. They will be unblinded - they will be told whether they were using the gel or placebo. They will also receive details on where to get counseling, HIV testing, contraception and other medical services.
The previous human study, CAPRISA 004, found that the tenofovir gel, when used before and after sexual intercourse, compared to the placebo gel was 39% more effective. The FDA (Food and Drug Administration) said that it would review VOICE data before deciding on whether to approve the vaginal gel. Even though the latest VOICE review showed that the gel is no better than placebo, another trial is underway, the results of which are expected in two years' time.
AIDS researchers have been seeking a gel that can protect women from HIV but still allows them to become pregnant, because they can use it without telling their sexual partner. Fear of being beaten if they ask the sexual partner to use a condom would not become an issue if they had an effective vaginal gel. A vaginal gel would give women much more independence.
Lead researcher, Sharon L. Hillier, said:
"Even when we have more information available to us, understanding why our results differed from the Caprisa results may not be clear."
Hillier and team wonder whether too few participants used the gel regularly, or perhaps there was something wrong with the scheduling. Some suggested that perhaps the gel caused inflammation, which in turn made it easier for HIV to enter. It will take about a year before they are able to assess this, the investigators informed.
Tenofovir, molecular formula C9H14N5O4P, is an antiretroviral drug; it is a nucleotide analogue reverse transcriptase inhibitor (NRTI), it blocks reverse transcriptase, an enzyme vital for viral production.
Written by Christian Nordqvist
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today
MLA
8 Dec. 2011.
Please note: If no author information is provided, the source is cited instead.
posted by Lorna Speid on 28 Nov 2011 at 8:58 am
These types of trials are a disgrace to the concept of informed consent, and could only be conducted in the Third World. Women formerly HIV negative will now be finding that they are HIV positive. How many such trials have to be conducted before advocates for these, often illiterate women in the Third World will speak up on their behalf?
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posted by Gloria Bhustu on 28 Nov 2011 at 10:45 am
Lorna, I am from what you patronizingly refer to as the "Third World". I am part of the trial, using the tablets. Informed consent was carried out professionally and properly. Please put your money where your mouth is, roll up your sleeves and come over here. Otherwise, allow us to decide these things for ourselves. OK? If it were not for the people out here carrying out these trials, millions more people around the world would have died.
We are not all illiterate and ignorant, and we pull together.
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posted by Jenny on 30 Nov 2011 at 2:36 am
The thought of giving a group of ladies the placebo in the trial is so sad - putting them at risk when they think they might be protected. The courage and sacrifice from anybody that participates in a clinical trial restores faith in the human race. Perhaps there is hope for us yet.
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