A panel of gynecologists, researchers and other medical experts on Wednesday at the end of a two-day meeting convened by FDA recommended the agency not set a specific standard of effectiveness for approval of oral contraceptives, the AP/Minneapolis Star Tribune reports (Bridges, AP/Minneapolis Star Tribune, 1/25).
The agency is reviewing the standards it uses when considering approval of oral contraceptives, and it asked the panel to make recommendations on the standards. Higher pregnancy rates in studies of new low-dose oral contraceptives have prompted the agency to reconsider what represents an "acceptable failure rate" for new drugs. The agency uses a measurement called the Pearl Index, which calculates a contraceptive's failure rate by measuring the amount of time women are exposed to a given product and the number of unplanned pregnancies that result. According to FDA documents released last week, the agency in the 1970s set a policy that it only approved oral contraceptives with failure rates less than 1.5 per 100 "woman-years," or the number of years a woman has used the drug. FDA has recently approved some pills with failure rates of more than two per 100 woman-years. The agency said that the number of pregnancies in clinical trials has increased in new oral contraceptives with lower dosages of estrogen and progestin. The increase in pregnancies is "consistent with less sustained ovulation suppression in new products as compared to the earlier higher-dose regimens," but there might be other reasons, FDA said (Kaiser Daily Women's Health Policy Report, 1/24). "You might have a product that has a higher failure rate but has all kinds of benefits," panel Chair Charles Lockwood of Yale University said, adding, "We were uncomfortable being pinned down to a specific number" (Stein, Washington Post, 1/25). Panelist Paul Blumenthal of Stanford University suggested the agency establish different classes of oral contraceptives based on their effectiveness (AP/Minneapolis Star Tribune, 1/25).