Nonoxynol-9 ineffective against HIV infection

The push for new microbicides gains fresh impetus with news from a just-released report which concludes that spermicides containing nonoxynol-9 (N-9) do not protect against HIV infection and may even increase the risk of HIV infection in women who use them on a frequent basis.1

The report advises women at high risk of HIV infection against using N-9 spermicides for contraception. However, spermicides with N-9 remain a birth control option for women at low risk for HIV, notes Tim Farley, PhD, a scientist with the Special Programme of Research, Development, and Research Training in Human Reproduction in the Department of Reproductive Health and Research of the Geneva-based World Health Organization (WHO).

Women at risk of HIV infection who want contraception should be informed that consistent and correct condom use is highly effective for pregnancy prevention and prevention of sexually transmitted infections, including HIV infection, according to the WHO.

The report is a result of an October 2001 technical consultation convened by the WHO in partnership with the Arlington, VA-based CONRAD Program. A panel of experts examined the available evidence on N-9 use; the report is a result of their findings. (Read the report on-line at the CONRAD web site, www.conrad.org. Click on the report title to view the report.)

"We reviewed the data; and bottom line, we feel it [N-9] is safe for infrequent use, but for frequent use, it is not," reports Henry Gabelnick, PhD, director of CONRAD.

Review key findings

In the 1970s and 1980s, laboratory tests showed that N-9 could inactivate the organisms that cause gonorrhea, chlamydial infections, and other sexually transmitted infections, as well as HIV. These tests fueled hopes that it could function as a contraceptive and a microbicide.

Subsequent research did not bear out the initial findings; in fact, a clinical trial of an N-9 gel showed that the HIV incidence was higher in women using the gel than in women using a comparison product.2 (Contraceptive Technology Update reported on the clinical trial in the article "Nonoxynol-9 fails test as female microbicide;" see the October 2000 issue, p. 119.)

Spermicides containing N-9 do not offer protection against two other common sexually transmitted diseases (STDs), cervical gonorrhea, and chlamydia, states the WHO/CONRAD report. This finding comes on the heels of recently published research that found N-9, when used with condoms, did not protect women from the two STDs any better than condoms used alone.3 (See CTU, June 2002, p. 63.)

When it comes to condoms with N-9 lubrication, there is no evidence that such condoms are any more effective in preventing pregnancy or infection than condoms lubricated with silicone; therefore, use of such condoms should no longer be promoted, states Farley. However, experts concluded that it was better to use an N-9 lubricated condom than no condom at all for infection protection. Experts also determined that N-9 spermicides should not be used during anal intercourse due to increased risk of infection.

The failure of N-9 to provide protection against HIV and other STDs should not lead to the conclusion that microbicides are not possible, notes Gabelnick. Instead, it should accelerate research to find safe and effective products.

About 4.6% of U.S. women use spermicidal products, according to data from the National Survey of Family Growth.4 What alternatives now in the research pipeline may soon be available to them?

The New York City-based Population Council is mounting a large-scale study of 6,000 women in southern Africa in a Phase III trial of its microbicide gel, Carraguard, a sulfated polysaccharide derived from seaweed. Safety data presented at the recent International AIDS Conference in Barcelona, Spain, indicate the microbicide is well tolerated.5,6

Look to 2004 for Phase II/III data on the contraceptive activity of BufferGel, a nonirritating, lubricant made of a high-molecular weight, cross-linked, polyacrylic acid. Data on the product’s anti-HIV capabilities are expected in 2005. The product is under development by the Baltimore-based ReProtect LLC. (See "2 trials will examine capability of microbicide," in CTU, April 2002, p. 41.)

Researchers are examining the safety and efficacy of a synthetic polymer gel, PRO 2000. Under development by Lexington, MA-based Indevus Pharmaceuticals, the microbicide previously was selected for a European Commission-funded Phase II safety trial in at-risk African women and a Phase II/III pivotal trial in Africa and India sponsored by the Bethesda-based National Institutes of Health.

References

1. World Health Organization. WHO/CONRAD Technical Consultation on N-9. Summary Report. Geneva; Oct. 9-10, 2001. Accessed at www.conrad.org.

2. Van Damme L, Chandeying V, Ramjee G, et al. Safety of multiple daily applications of COL-1492, a nonoxynol-9 vaginal gel, among female sex workers. COL-1492 Phase II Study Group. AIDS 2000; 14:85-88.

3. Roddy RE, Zekeng L, Ryan KA, et al. Effect of nonoxynol-9 gel on urogenital gonorrhea and chlamydial infection. JAMA 2002; 287:1,117-1,122.

4. Abma JC, Chandra A, Mosher WD, et al. Fertility, family planning, and women’s health: New data from the 1995 National Survey of Family Growth. Vital Health Stat 1997; Series 23, No. 19.

5. Coetzee N, Hoosen A, Blanchard K, et al. A randomized, placebo-controlled, double-blind expanded safety trial of Carraguard; microbicide gel in South Africa: Signs and symptoms of genital irritation. Presented at the XIV International AIDS Conference. Barcelona, Spain; July 10, 2002.

6. Kilmarx PH, Supawitkul S, Yanpaisarn S, et al. A year-long, randomized, controlled clinical trial of a carrageenan gel as a vaginal microbicide: Effect on reproductive tract infection (RTI) rates. Presented at the XIV International AIDS Conference. Barcelona, Spain; July 10, 2002.