Tara P.
Turner, Pharm.D.
Center
for Drug Evaluation and Research (HFD-21)
Food
and Drug Administration
Rockville, MD 20857
Dear Dr. Turner:
The
undersigned are AIDS activists working to end the AIDS epidemic by advancing
research on HIV/AIDS. We are interested
in vaginal microbicide research because of its obvious potential in the
prevention of HIV transmission through a woman-controlled mechanism.
Our
concerns regarding microbicide research extend to rectal safety and
efficacy. Although many people associate
anal intercourse exclusively with male homosexual activity, it is clear that
anal intercourse is a frequent practice among heterosexuals as well.
Approximately 6% - 8% of heterosexual survey respondents reported anal
intercourse within the past 12 months. (Source: National Health and Social Life Survey, National Opinion
Research Center, University of Chicago, 1992). Nearly 80% of these heterosexual respondents
did not use condoms.
Given
the unfortunate history of the marketing and use of nonoxynol-9, it is clear
that any vaginal microbicide will be used by a wide range of people in
conjunction with anal intercourse, notwithstanding any
instructions for use. Again, given the
history of nonoxynol-9, vaginal products must be shown to be safe for rectal
use in order to avoid inadvertently increasing the transmission of HIV. Differences in the physiology and immunology
of the anorectal and vaginal mucosa require separate and specific study of
safety in the anorectal environment.
Participants
in trials of vaginal safety and efficacy must be informed that the products
have not been tested for safety rectally, should not be used rectally and that,
absent safety data, use of the product when engaging in anal intercourse may
increase the risk of HIV transmission. Any microbicides approved for vaginal
use should also carry explicit warning labels warning against rectal use until
such time as rectal safety and efficacy studies on these products have been
completed.
We
favor a more aggressive research program within the National Institutes of
Health on the rectal mucosa, including development of safe and effective
microbicides that could be used by anyone who engages in anal intercourse. Such a research program would also provide
valuable data to guide the development of safe and effective vaginal
microbicides.
These
are urgent research agendas to advance our ability to prevent new HIV
infections.
Very
truly yours,
Lynda
Dee,
Robert
Munk, PhD, Arroyo
Gerry
Spillman,