Nonoxynol-9 fails test as female microbicide
The search for a safe method of HIV protection that women can control has taken on added urgency now that results from a large international study indicate that nonoxynol-9 (N-9), a spermicide with microbicidal properties, is ineffective in stopping the disease.
Because N-9 is available as an over-the-counter spermicide, public health officials had hoped it would prove the fastest route to a commercially available product for female-controlled chemical prevention of HIV. Research had indicated that N-9 and other detergents inactivate HIV in vitro1-3 and provide partial protection against cervical infections and chlamydia.4-7
In 1996, the Geneva-based Joint United Nations Programme on HIV/AIDS (UNAIDS) launched an international trial of an N-9 gel, code-named COL 1492 and marketed in the United States as Advantage-S by Columbia Laboratories of Miami. The study was conducted as a triple-blind randomized multicenter trial among female sex workers, with test sites in Benin, Côte d’Ivoire, Thailand, and South Africa.
Researchers tested the effectiveness of a gel containing 52.5 mg of N-9 compared with an inactive placebo gel. Women were chosen at random from volunteers who were informed of the risks and who agreed in writing to take part in the tests. Study participants were given intensive condom counseling, free condoms, free treatment for all sexually transmitted diseases, and regular check-ups.
Results from the study, presented at the recent XIII International AIDS Conference in Durban, South Africa, made an immediate impact on the public health community. The study shows that women who were randomized to use the N-9 gel became infected with HIV at about a 50% higher rate than women who used the placebo gel.8 In addition, the more frequently women used only N-9 gel without a condom to protect themselves, the more their risk rose for becoming infected.
Based on the results from the UNAIDS trial, the Atlanta-based Centers for Disease Control and Prevention (CDC) has issued the following recommendations:9
• Any community delivering hierarchical prevention messages that counsel individuals who can’t use a condom to consider spermicides with N-9 for HIV prevention should revise those messages immediately. The UNAIDS study suggests that the use of N-9 for HIV prevention may be harmful, says the CDC.
• Anyone using N-9 as a microbicide to protect themselves from HIV transmission during anal intercourse should be informed of the ineffectiveness of the agent and warned of the potential risk of that practice.
• The CDC has never recommended N-9 alone for HIV prevention, but current recommendations do emphasize the consistent and correct use of condoms, with or without a spermicide. While the level of N-9 used as a lubricant in condoms is much lower than the level found to be harmful in the UNAIDS study, CDC will re-evaluate this guidance. In the interim, while N-9 will not offer any additional protection against HIV, a condom lubricated with N-9 is clearly better than using no condom at all. The protection provided by the condom against HIV far outweighs the potential risk of N-9. If given the choice, condoms without N-9 may be a better option for HIV prevention.
The CDC notes that the UNAIDS trial was conducted among a very high-risk population: commercial sex workers who used a great deal of the N-9 gel on a frequent basis. The adverse effects recorded in the trial might not be seen at the same level among women who are using N-9 spermicides less frequently or in different formulations, the agency notes. "However, given that N-9 has now been proven ineffective against HIV transmission, the possibility of risk, with no benefit, indicates that N-9 should not be recommended as an effective means of HIV prevention," states Helene Gayle, MD, MPH, director of the CDC’s National Center for HIV, STD, and TB Prevention, in a public letter to the health community.9
UNAIDS and CDC will hold meetings over the next few months to consider official revisions to public health guidelines for the use of N-9 for HIV prevention and for pregnancy prevention in populations at high risk for HIV. Prevention guidelines must be re-evaluated based on the UNAIDS trial results, the CDC states. (See story, p. 121, for views on use of N-9 as a contraceptive.)
References
1. Malkovsky M, Newell A, Dalgleish AG. Inactivation of HIV by nonoxynol-9. Lancet 1988; 1:645.
2. Judson FN, Ehret JM, Bodin GF, et al. In vitro evaluations of condoms with and without nonoxynol-9 as physical and chemical barriers against Chlamydia trachomatis, herpes simplex virus 2 and human immunodeficiency virus. Sex Transm Dis 1989; 16:51-56.
3. Jones BM, Geary I, Lee ME, et al. Susceptibility of Haemophilus ducreyi to spermicidal compounds in vitro. Genitourin Med 1991; 67:268-269.
4. Zekeng L, Feldblum PJ, Oliver RM, et al. Barrier contraceptive use and HIV infection among high-risk women in Cameroon. AIDS 1993; 7:725-731.
5. Kreiss J, Ngugi E, Holmes K, et al. Efficacy of nonoxynol-9 contraceptive sponge use in preventing heterosexual acquisition of HIV in Nairobi prostitutes. JAMA 1992; 268:477-482.
6. Weir SW, Feldblum PJ, Zekeng L, et al. The use of nonoxynol-9 for protection against cervical gonorrhea. Am J Pub Health 1994; 84:910-914.
7. Rosenberg M, Gollub E. Methods women can use that may present sexually transmitted diseases, including HIV. Am J Pub Health 1992; 11:1,473-1,478.
8. Van Damme L. Advances in topical microbicides. Presented at the XIII International AIDS Conference. Durban, South Africa; July 12, 2000.
9. Centers for Disease Control and Prevention. Notice to readers: CDC statement on study results of product containing nonoxynol-9. MMWR 2000; 49:717.
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