FDA in documents released Thursday announced it is reconsidering its standards for reviewing the failure rate of new oral contraceptives with lower doses of estrogen and progestin, the Wall Street Journal reports.
According to the Journal, higher pregnancy rates in studies of new low-dose oral contraceptives have instigated 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, 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 Journal reports.
FDA 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.
Scott Monroe, acting head of the agency's reproductive-drugs division, said the variations between the new contraceptives and the old pills might "not be statistically different." According to the Journal, FDA in an upcoming meeting will seek its advisers' input for new guidelines to review new oral contraceptives.
Source: Kaiser Family Foundation