Dapivirine gel

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Trial of microbicide ring in final phase

May 23, 2011 at 6:41 AM by AHN · Leave a Comment

Kigali, Rwanda (IRIN) – Rwanda is in the third and final phase of testing a vaginal ring containing antiretrovirals, which, if successful, could provide an important female-controlled method of HIV prevention.

Malawi, Rwanda, South Africa and Zimbabwe have all been selected to conduct the final phase of the trial. Phases I and II – conducted in Kenya, Malawi, Rwanda, South Africa – assessed the safety and acceptability of a daily application of a gel containing the ARV, dapivirine.

“Phases I and II were completed successfully; this means that the microbicide has been evaluated and found to be safe and acceptable,” Gilles Ndayisaba, the principal investigator at Project Ubuzima, told IRIN/PlusNews. “Even if in Rwanda we conducted phase I and II on the gel, these phases have been done with the ring in several others [countries] and they were successful,” he added.

Phase I trials involved small numbers of women, followed by expanded safety trials, Phase I/II, which gathered additional safety data among more participants over longer periods. Once the safety trials are complete, longer-term safety and efficacy trials begin. Phase III trials are conducted among high-risk participants so that researchers can see if there is a difference in infection rates between women who use the active microbicide product versus those who use a placebo. This phase looks specifically at the efficacy and gathers information to proceed with putting the product on the general market.

In Rwanda, the trials are being conducted by a local NGO, Project Ubuzima, with the International Partnership for Microbicides. The project has carried out safety trials for dapivirine gel among more than 60 women and has conducted an HIV incidence study among 1,250 female VCT clients and 800 high-risk women in the capital, Kigali, in preparation for the final phase.

An estimated 3,000 HIV-negative women aged between 18 and 40 will participate in the trial in all selected countries – between 400 and 600 will come from Rwanda; the trial is expected to last three years.

“Potential participants are well-educated on clinical research in general and first have to sign an informed consent form which includes all information concerning risks and benefits while participating in the study,” said Marie-Michelle Umulisa, the community outreach manager at Project Ubuzima. “These are reviewed by the Rwandan National Ethics Committee to protect participants’ rights.”

Each participant will use the ring for a minimum 15 months or a maximum 33 months. “It is likely that products that can be applied less frequently like the ring will be more acceptable and will achieve better adherence,” Ndayisaba said. “Vaginal rings need only to be replaced every four weeks and may therefore have benefits over dosage forms that need to be used more frequently.”

The researchers say dapivirine is advantageous because it is not used in current HIV/AIDS treatment regimens so there is less potential for drug resistance. They say the vaginal ring is cheap to manufacture, comfortable, flexible and can be self-inserted; it is intended to provide long-term protection during anticipated and unanticipated sexual intercourse.

Uncertainties

According to Evelyn Kestelyn, executive director of Project Ubuzima, there are advantages to being one of the countries conducting a trial. “When the products finally come on the market… countries that were selected to implement phase III will get the products for free or will purchase them at a subsidized price.”

However, women in Kigali remain uncertain about whether they would use a microbicide ring should the ongoing trial prove successful.

“I would need to be extremely sure it works well before I can entrust my life with such a thing; I mean I would want to be sure it doesn’t have any particular side-effects,” said Agatha Ingabire.

Should the product make it on to the market, Project Ubuzima plans a major campaign to sensitize Rwandans on the microbicide’s function.

“We intend to undertake a huge sensitization process, starting with community leaders and gradually we shall trickle this down to the other masses,” said Umulisa. “Community acceptability of this project is key for its success.”

Globally, a number of microbicide trials are ongoing , testing gels and rings. In 2010, the biggest success was recorded in a study by the Centre for the AIDS Program of Research in South Africa, which found that a vaginal gel containing the ARV tenofovir was 39 percent effective in reducing a woman’s HIV risk when used for about three-quarters of sex acts and 54 percent effective when used more consistently.

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– Provided by Integrated Regional Information Networks.