Spermicides with N-9 focus of clinical trial
Research is now under way in getting up-to-date contraceptive efficacy information on over-the-counter (OTC) spermicidal products containing nonoxynol-9 (N-9), ending a reliance on decades-old data.
Family Health International (FHI), a reproductive health research firm in Research Triangle Park, NC, is overseeing the three-year multicenter clinical trial. Funding for the $4.7 million project comes from the National Institute of Child Health and Human Development in Bethesda, MD.
The main objective of the trial is to evaluate and compare the contraceptive effectiveness of five spermicidal preparations, says Elizabeth Raymond, MD, MPH, associate medical direc -tor of the biomedical affairs division at FHI. Researchers also will be looking at the safety, acceptability, and consistency of use of these preparations.
OTC spermicides, which rely on several formulations to deliver a chemical to kill sperm, have been in use in the United States for more than 40 years. These products were "grandfathered" into U.S. Food and Drug Administration (FDA) regulations under the monograph process. Most published clinical trials of spermicide used alone do not meet modern standards for study design and analysis; therefore clinicians must be cautious when comparing the efficacy of spermicides with the effectiveness of other contraceptive methods, warn the authors of Contraceptive Technology.1
The FDA, following a review of the spermicide drug class, determined in 1995 that the effectiveness of N-9 cannot be considered separately from its carrier, be it foam, pill, gel, cream, or suppository. The agency has stated that the active ingredients in marketed spermicides generally are safe, but their effectiveness in final product formulations is highly variable.2
Concern was raised following the 1995 ruling that OTC spermicide manufacturers may have to file new drug applications and submit clinical efficacy data to receive FDA approval. The costs of mounting such studies may convince many manufacturers of spermicide, which represents a small segment of the total contraceptive market, to withdraw their products. Such a move would leave women without a product that is easily available, does not require a provider’s prescription, and is female-controlled. (See Contraceptive Technology Update, February 1997, p. 17, for more on the search for updated efficacy information.)
The current trial has been designed to satisfy the FDA’s request for information, says Raymond. The data may be used to define classes of spermicides so individual brands need not be tested, although this approach is still under consideration, she notes.
Five spermicidal preparations will be examined in the clinical trial. Women will be random ly assigned to one preparation and followed for seven months to obtain efficacy data. Three of the preparations are gel products with varying amounts of N-9, which will allow researchers to determine if the amount of spermicide influences efficacy rates. A suppository tablet and a film preparation share the same N-9 level as one of the gels, which provides a mechanism to determine whether the method of delivery affects the efficacy rate.
"N-9 is in use in many different products and many different varieties of products, and we really don’t know if there is an optimal dose or an optimal way of using it," says Kurt Barnhart, MD, MSCE, assistant professor of OB/GYN and human reproduction at the University of Penn sylvania Medical Center in Philadelphia, one of the centers for the clinical trial. "This comparison will not only help us to decide how good N-9 is overall, but if one product is actually superior to another."
Women now enrolling
The multicenter trial includes 11 study sites: Planned Parenthood of Central and Northern Arizona in Phoenix, University of Arizona Health Sciences Center in Tucson, Johns Hopkins Medical Services Corp. in Baltimore, Minneapolis Medical Research Foundation at Hennepin County Medical Center in Minneapolis, University of Pennsylvania Medical Center in Philadelphia, Magee-Women’s Hospital in Pittsburgh, Medical University of South Carolina in Charleston, Baylor College of Medicine in Houston, University of Texas Health Sciences Center at San Antonio, Vermont Women’s Health Center in Burlington, and Eastern Virginia Medical School in Norfolk.
Finding women who are interested in using spermicides as their sole contraceptive method can be challenging, says Raymond. Recruitment began in June, with some 200 women enrolled as of the first of November. A total of 1,800 women will be included in the trial.
Philadelphia has been successful in recruiting for the study because it is advertising spermicides as an alternative to hormonal contraception, Barnhart reports. "Many women prefer a nonhormonal method, as well as a method that is under their control," he notes.
References
1. Hatcher RA, Trussell J, Stewart F, et al. Contraceptive Technology. 17th ed. New York, NY: Ardent Media; 1998.
2. Cruzan S. Rules Proposed for Spermicides. Food and Drug Administration. Feb. 3, l995.
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