Study: Gel Fails to Stop HIV Infection
February 20 2008 12:00 AM ET
anti-AIDS vaginal gel to make it through late-stage testing
failed to stop HIV infection in a study of 6,000 South
African women, disappointed researchers announced
The study was
marred by low use of the gel, which could have undermined
results, they said. Women used it less than half the number
of times they had sex, and only 10% said they used it
every time as directed. Scientists are still analyzing
the results to see if this made a difference. They
also plan more tests on a revamped gel containing an
AIDS drug that they hope will work better.
The gel used in
the current study did prove safe, however, and
researchers called that a watershed event.
But for now, the
effort is the latest disappointment in two decades of
trying to develop a microbicide -- a cream or gel women
could use to lower their risk of getting HIV through
sex. A female-controlled method is especially needed
in poor countries where women often can't persuade men
to use condoms.
A year ago,
scientists stopped two late-stage tests of a different gel
after early results suggested it might raise the risk of HIV
infection instead of lowering it.
The new study
tested Carraguard, a microbicide developed by the nonprofit
organization New York-based Population Council. It contains
carrageenan, which comes from seaweed and is widely
used in the food and cosmetics industries as a gel,
stabilizer, and thickening agent. Lab, animal, and
early human tests suggested it might prevent HIV and other
sexually spread infections.
The latest study
was done from March 2004 through March 2007 in
Gugulethu, Isipingo, and Soshanguve, all in South Africa.
More than 9,000 women, average age 31, volunteered for
the study. About 275 tested positive for HIV and were
disqualified. In all, 6,202 women were randomly given
either Carraguard or a placebo gel. Neither the women nor
the study staff knew who received what. All received
safe-sex counseling and condoms.
participated from nine months to two years, with 4,244
completing the study. About 18% dropped out, often
because they became pregnant and the gel is not known
to be safe for use in pregnancy. Another 13% could not
be found for follow-up information.
At the end of the
study, there were 134 new HIV infections in the
Carraguard group and 151 in the fake gel group -- a rate of
3.3 infections per 100 women each year in the
microbicide group and 3.7 for the placebo group.
''The results are
comparable,'' with no statistically significant
difference, said Khatija Ahmed, a microbiologist who headed
the study's Setshaba Research Centre site near
However, women in
the study used the gels only 44% of the time, and some
used it hardly at all. Researchers are still analyzing the
numbers to see what that means. If nonuse was far
greater in the microbicide group than the placebo
group, ''it could have had an impact on our final study
results,'' said Barbara Friedland, the study's behavioral
A plus: Reported
condom use doubled, from 33% at the start of the study
to 64% during it. Other sexually spread infections declined.
The study was
paid for by the Bill & Melinda Gates Foundation and the
U.S. Agency for International Development, or USAID. Jeff
Spieler, an official at USAID, called the trial
''groundbreaking work'' in a statement. ''We have
always known that the path to developing a successful
microbicide would be a long one.''
Council hopes to start tests this year of a revamped
Carraguard containing an experimental AIDS drug, MIV-150.
The group also has studies under way of a
contraceptive version of the gel, Carraguard plus
hormones. (Marilynn Marchione, AP)