What’s in store for on-latex barrier methods
Do you have patients who prefer barrier methods such as diaphragms but are latex-sensitive? Family planning clinicians are seek-ing information on existing products, as well as developments leading to new methods.
Milex Products of Chicago manufactures a silicone diaphragm, according to Ruth Cogan, vice president. The only silicone diaphragm on the U.S. market, it is distributed directly to physicians and clinics and is not sold through pharmacies, she says. The Milex silicone diaphragm has a wide-seal rim and is offered in two rim styles: arcing rim and Omniflex coil spring.
For patients who aren’t comfortable with a diaphragm but want a latex-free barrier method, suggest using the Reality female condom from the Female Health Company in Chicago or the Avanti male condom from London International Group, says David Archer, MD, professor of OB/GYN at the Jones Institute for Reproductive Medicine at the Eastern Virginia Medical School in Norfolk. Both condoms are made with polyurethane, a good choice for latex-sensitive patients. Spermi-cides alone, such as vaginal contraceptive film, spermicidal gel, or foaming spermicidal tablets provide another alternative, Archer says.
While woman-controlled vaginal barriers such as diaphragms, cervical caps, and female condoms are simple to use and non-invasive, consistent and correct use is essential for success, state the authors of Contraceptive Technology.1 Most failures occur because the method is not used.
"Based on my read of consumers, barrier contraceptives have some advantages but are poorly received by couples for a variety of reasons," Archer comments. "They may interrupt the sex act, call for the insertion of something into the vagina, be messy to touch or for the partner, result in vaginal discharge after use, and offer a lack of reliable significant efficacy [Pearl rates of 8.0% or higher]."
Three methods in pipeline
Three new woman-controlled silicone barrier devices are in various stages of development, says Henry Gabelnick, PhD, director of the Contra-cep-tive Research and Development (CONRAD) Program in Arlington, VA. Clinical study data are being prepared for the U.S. Food and Drug Administration (FDA) for premarketing approval of the Femcap, a silicone cervical cap, he says.
The Femcap, shaped like a sailor’s cap and offered in three sizes, was developed by Alfred Shihata, MD, a researcher in Del Mar, CA. Clinical studies show that the Femcap, when used with a nonspermicidal or spermicidal lubricant, appears to be comparable with the diaphragm used with spermicide in preventing sperm from entering midcycle cervical mucus.2
Family Health International (FHI) of Research Triangle Park, NC, was involved in the CONRAD-led efficacy study comparing Femcap with the diaphragm, says Laneta Dorflinger, PhD, director of clinical trials. More than 800 couples participated in the trials, which looked at safety, efficacy, and acceptability, says Archer, who also participated in the study. Look for findings to be published this year.
Efforts continue to gain FDA approval for Lea’s Shield, a "one-size-fits-all" silicone barrier device developed by YAMA Corp. of Millburn, NJ. An FDA advisory committee ruled in Oct. 1996 that there was a lack of adequate data on the device’s effectiveness to allow for U.S. market approval. (For the FDA’s ruling, as well as YAMA’s plans to extend its clinical study, see Contraceptive Technology Update, January 1997, p. 3.)
CONRAD and FHI are working with YAMA in its second attempt for FDA approval, Gabelnick says. While Lea’s Shield will be available in the United States by prescription only, it is currently sold as an over-the-counter product in Germany, Switzerland, Austria, and Canada.
The Program for Appropriate Technology in Health in Seattle has worked with CONRAD since 1994 to develop an entirely new female barrier device. Known as the SILCS intravaginal barrier contraceptive, the device has been designed with an eye toward simplified fitting and ease of use and removal. Development is at a very early stage with evaluation of a number of prototypes, Gabelnick says. The current prototype is being readied for further production to perform Phase I clinical studies.
Until now, examinations of the device have focused on comfort and fit, he says. Clinical studies will begin in 1998; efficacy trials are envisioned for 1999. Much groundwork must be covered before the device is ready for market approval.
References
1. Hatcher RA, Trussell J, Stewart F, et al. Contraceptive Technology. 16th edition. New York City: Irvington Publishers; 1994, p. 191.
2. Mauck CK, Baker JM, Barr SP, et al. A phase I study of Femcap used with and without spermicide: Postcoital testing. Contraception 1997; 56:111-115.
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