Carraguard Microbicide Gel Fails to Reduce Risk of HIV Infection in Women
On
February 18, researchers delivered another dose of bad news on the HIV prevention
front, reporting that the experimental vaginal microbicide candidate Carraguard
- though apparently safe - did not reduce the risk of women becoming infected
with the virus.
Below
is the text of a press release announcing the findings from the Population Council,
which was developing Carraguard, one of the first microbicides to reach Phase
3 clinical testing:
Trial Shows Anti-HIV Microbicide
Is Safe, but Does Not Prove It Effective
Research
Advances HIV Prevention Field
Johannesburg,
South Africa and New York, NY (18 February 2008) -- The Phase 3 clinical trial
of the Population Council's candidate microbicide Carraguard found the product
to be safe for vaginal use. 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 Peter Donaldson.
"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 U.S. 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 U.S. 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."
More
information about the Population Council's microbicides program is available at
www.popcouncil.org/microbicides.
About
the Population Council
The Population Council is an international,
nonprofit, nongovernmental research organization that seeks to improve the well-being
and reproductive health of current and future generations around the world and
to help achieve a humane, equitable, and sustainable balance between people and
resources. The Council conducts biomedical, social science, and public health
research and helps build research capacities in developing countries. Established
in 1952, the Population Council has been working in Africa since the 1960s and
in South Africa for nearly a decade. It has a global network of regional and country
offices, including one in Johannesburg, South Africa, and ten others in Africa.
During the past decade, the Council has worked on projects in 25 African countries.
About
microbicides
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. More information
about the field is available at www.global-campaign.org
and www.microbicide.org.
02/22/08
Source
Population
Council. Trial Shows Anti-HIV Microbicide Is Safe, but Does Not Prove It Effective.
Press Release. February 18, 2008.
