Anti-HIV Microbicide trial failed.

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Anti-HIV Microbicide trial failed.

(AIDS INDIA e FORUM) The Phase 3 clinical trial of the Population

Council's candidate microbicide Carraguard® found the product to be

safe for vaginal use. But the trial did not demonstrate that

Carraguard is effective in preventing male-to-female HIV transmission

during vaginal intercourse.

There were 134 new infections in the Carraguard group (an incidence

of 3.3 infections per 100 woman-years) and 151 new infections in a

placebo group (an incidence of 3.7 per 100 woman-years). The

difference between the two groups is not statistically significant.

Carraguard is the first product developed as a microbicide to

complete the final phase of product testing. " We are disappointed

that this trial did not show Carraguard to be effective; nonetheless

the completion of this trial is a milestone in HIV prevention

research, " said Population Council president son. " The

trial has contributed significantly to the field's body of knowledge

regarding product development, trial design, and women's and their

partners' willingness to use a vaginal gel consistently. The data

from the trial will be used by the Population Council and others

working on microbicides to improve future products and trials. "

The Carraguard trial, which began in March 2004 and ended in March

2007, enrolled 6,202 women and was conducted at three sites in South

Africa: the Setshaba Research Centre, through the University of

Limpopo/Medunsa campus; the Empilisweni Centre for Wellness Studies,

through the University of Cape Town; and the Isipingo Clinic, through

the Medical Research Council of South Africa. These sites are located

in areas where the HIV epidemic is acute.

Carraguard is made of carrageenan, a seaweed derivative that is on

the US Food and Drug Administration's list of products " Generally

Recognized As Safe " for consumption and topical application.

Laboratory research has shown Carraguard to be effective in blocking

cells from becoming infected by HIV and in protecting mice from some

other sexually transmitted infections. Carraguard and similar

carrageenan formulations had undergone extensive safety testing

involving more than 850 women and men in earlier clinical trials in

Australia, Chile, the Dominican Republic, Finland, South Africa,

Thailand, and the United States.

Half of the women enrolled in the Phase 3 study were given Carraguard

gel and condoms, and the other half received a placebo gel and

condoms. Participants received HIV education, gynecological exams,

risk-reduction and safer-sex counseling, and testing and treatment

for curable sexually transmitted infections. The Population Council

funded medical and psychological services for women who were HIV-

positive at screening or became HIV-positive during the course of the

trial.

The randomized, double-blind study found that there were no safety-

related differences between women using Carraguard and women using

the placebo, and that gel-related side effects were minor and

infrequent. This finding is important because Carraguard is a key

component of next-generation microbicide candidates being developed

at the Population Council. Several of these candidates combine

Carraguard with one or more ingredients that have been shown to be

effective in preventing virus transmission in laboratory settings.

" The Population Council will use these trial results to accelerate

the development of effective means for women to protect themselves

against HIV, " said Naomi Rutenberg, director of the Population

Council's HIV and AIDS program.

The trial was funded by the US Agency for International Development

(USAID) and the Bill & Melinda Gates Foundation. Jeff Spieler, senior

science advisor in population and reproductive health at USAID,

said, " We have always known that the path to developing a successful

microbicide would be a long one. The Population Council has done

groundbreaking work in completing this trial, even though we are

terribly disappointed that the product was not shown to be effective.

Now we all have to redouble our efforts to develop a microbicide that

women can use to protect themselves. "

Vaginal microbicides are being developed as female-initiated methods

for reducing male-to-female transmission of HIV and possibly other

sexually transmitted infections when used during sex. Women need more

options to protect themselves from infection because current

prevention strategies are not always feasible. While no effective

microbicides yet exist, they would most likely be formulated as gels,

creams, foams, or vaginal rings.

References:

http://www.global-campaign.org

http://www.microbicide.org

www.popcouncil.org/microbicides

http://www.popcouncil.org/mediacenter/newsreleases/Carraguard_Findings.html