Pending review by the U.S. Food and Drug Administration (FDA), women in this country may soon have access to a contraceptive patch as one of several new birth control options.

The patch, known as Ortho Evra (TM), works in much the same way that combined oral contraceptives do. It uses two female hormones--a progestin and an estrogen--to prevent ovulation and to trigger other physiological changes that interfere with conception. Unlike oral contraceptives, however, Ortha Evra delivers these hormones through the skin.

Ortho Evra was developed by the R.W. Johnson Pharmaceutical Research Institute (a division of Johnson & Johnson), which applied in December 2000 for FDA approval to market the product. The patch, which uses the estrogen ethinyl estradiol and the progestin norelgestromin, can be worn in a number of places on a woman's body but is usually applied to the lower abdomen or buttocks. It must be changed every 7 days (on the same day of the week) for three weeks, followed by a fourth week with no patch to allow menstruation to occur.

Oral contraceptives: the compliance issue

With consistent use, combination oral contraceptives (COCs), which contain a progestin and an estrogen, are highly effective. According to the authoritative medical text Contraceptive Technology, when taken in perfect compliance with the prescribed daily dosing schedule, COCs have a first-year failure rate of just 0.1%, meaning only one woman in 1000 will become pregnant in the first year of use. But nobody's perfect, and absolute compliance with a long-term daily dosing schedule--month after month, year after year--is just about as rare. Under real-world conditions of typical compliance, the first-year failure rate for COCs is estimated to be around 5% (50 women in 1000 become pregnant). Developers of the patch, with its one-week duration, believe that Orth Evra may hold an important advantage in being a more convenient, compliance-promoting alternative for COC users.

Initial findings on the patch

In a recent study (Audet et al. JAMA 2001;285:2347-2354), 1417 women between 18 and 45 years of age, who were sexually active and presumed able to become pregnant, were randomly assigned to use either the Ortho Evra patch or a popular COC. No other contraceptives were allowed during the study. Two-thirds of the women were followed for 6 months; the remaining third were studied for 13 months. Eight hundred twelve wore the patch; 605 took the COC.

The results? Patch users were significantly more compliant than their COC-taking counterparts. Women in the patch group properly changed their patches in 88.2% of their menstrual cycles, while the COC group took their pills on schedule in only 77.7% of cycles. The patch group had fewer method failures (pregnancies) than the COC group, but the difference was not statistically significant, meaning the researchers could not rule out the possibility that the difference was a matter of chance.

Some women in the patch group had patch-site reactions (skin reactions). The patch group also had significantly more breakthrough bleeding and/or spotting in the first two months and significantly more breast discomfort and dysmenorrhea, but overall, patch and pill were judged similarly well tolerated.

In addition, according to data presented at last year's meeting of the American College of Obstetricians and Gynecologists, three earlier international clinical trials of that enrolled a total of 3,329 women found compliance rates of 93%, 94.4%, and 92.7% with the Ortho Evra patch, compared with compliance rates of 78.4% and 87.8% for two different of COCs.

The operative assumption here is that better compliance yields more effective birth control, and common sense suggests this would be true, but superior effectiveness of the patch compared with COCs has yet to be clinically proved.

On the horizon?

Assuming 12 months for FDA review and approval, it's feasible the Ortho Evra patch system could be available to women in this country as early as Spring of 2002. In addition, just a bit further back up the new drug pipeline is another transdermal contraceptive patch under development by Levotech, Inc. The Levotech patch contains ethinyl estradiol and levonorgestrel, a more conventional hormonal combination. Recent months have also seen the approval of two new oral contraceptives (Cyclessa and Yasmin), a new monthly injectable (Lunelle), and a new hormone-releasing intrauterine device (Mirena).

It seems after years of stagnation following the Dalkon Shield IUD fiasco, contraceptive technology in the U.S. is undergoing a bit of a renaissance--good news for women of child-bearing potential who may not have been adequately served by the previous available choices.