By Otesa Middleton
WASHINGTON — Researchers have dozens of creams, gels, foams, suppositories, sponges and films in development that women can apply to their bodies before sex — not to prevent pregnancy, but to prevent infection with the AIDS virus.
Scientists say these experimental products could give women, the fastest- growing segment of the world’s infected population, more power to protect themselves from the disease.
However, because it is a brand-new approach with no federally approved products, the Food and Drug Administration (News – Websites) asked its outside antiviral experts to recommend parameters for testing the safety and effectiveness of the microbicides.
Companies have already begun submitting proposals on studying those products to the agency, said Dr. Debra B. Birnkrant, director of the FDA’s division of antiviral drugs.
“We’ve been wrestling with these issues for a few years now,” she told the panel during the daylong meeting. “There is extreme urgency to develop a topical microbicide rationally and get it on the market as soon as possible.”
Many studies of the virus-killing products are being conducted in developing countries with rampant spread of HIV infection.
The FDA wanted advice on whether tests should compare the microbicide against condom use, an inactive placebo or both; how long the trial should be; and what data would be needed to show the microbicide worked.
The panel didn’t reach a consensus and the FDA didn’t ask for a formal vote. Instead, the 17-person panel said the first approved microbicide will likely face the highest hurdle. Subsequent products will benefit from the knowledge gained by the first successful product.
The panel’s chairman, Dr. Roy M. Gulick, director of clinical trials at the Weill Medical College of Cornell University, said, “Everything will change when one microbicide shows safety and efficacy.” He added, “There is no one right answer here,” and that “in summary, we’re not sure. All approaches have value.”
Several panelists spoke against requiring a comparison to condom use, because in some countries where the products will be tested, women don’t have the authority to demand condom use. Others panelists were concerned that approving a microbicide may influence women who currently insist on condom use by male sex partners to stop using condoms, currently the best HIV prevention among sexually active people.
“Condoms are the best you can do,” Dr. Gulick said.
However, the panel said, condom use is typically inconsistent even among people who use them, and unless condoms are used all the time, they can’t effectively protect against HIV spread.
The FDA is also incorporating the lessons it learned from studying the widely used spermicide nonoxynol-9 as a possible HIV prevention. Trials of the contraceptive showed it actually increased the risk of HIV infection because it caused openings in the skin that were more suitable for disease transmission.
The Population Council in New York has been studying a possible HIV-blocking agent since the late 1980s, said Dr. Donald E. Waldron, the group’s medical director. It has already tested 165 women in Thailand and 400 women in South Africa with its compound Carraguard. Now, in a larger trial, Carraguard will be tested in 4,500 more South African women.
One company, Biosyn Inc., has three such compounds in three different phases of development, said Dr. Richard Bax, the firm’s chief scientific officer. One product it is working on is about to enter a large, 12-month trial in Ghana and Nigeria. Biosyn wants the product to serve a dual purpose in the U.S. as an HIV- and pregnancy-prevention product.
“Now is the time to do a statistically correct, simple study,” Dr. Bax told the panel. “In the U.S. there are 20,000 HIV transmissions per year due to heterosexual sex. There are 16,000 per day in the developing world.”