New contraceptive goes against the flow

June 18, 2007

The FDA has approved a new oral contraceptive for continuous use.

Women looking for an appropriate contraceptive to fit their lifestyles might marvel at the concept of not having a period-ever. And that idea may now be a reality with the recent approval of Lybrel from Wyeth Pharmaceuticals, the first oral contraceptive (OC) designed for continuous use without a break for menstruation.

But despite the fact that the new OC can prevent a monthly period and pregnancy, women tend to bleed while taking Lybrel, a fact brought up at a recent Food & Drug Administration press conference announcing the drug's approval. "Women who use Lybrel would not have a scheduled menstrual period but will most likely have unexplained breakthrough bleeding or spotting," said David Shames, M.D., acting deputy director of the Office of Drug Evaluation III at the FDA's Center for Drug Evaluation & Research-although, he pointed out, the occurrence of unscheduled bleeding did decrease over time during the primary clinical trial. Specifically, 59% of women had no bleeding or spotting during the last month of the year-long study.

Another important point, according to Goliak, is that the lack of a regular period could make it difficult for a woman to recognize that she is pregnant if the contraception failed. "Women should take a pregnancy test if they believe they could be pregnant," she said.

The real concern with Lybrel may be in what we don't know, noted Brown. "We don't know the long-term effects of continuous OC use without a menses," she said. Although considered a "low-dose" OC, Lybrel used continuously for a year gives a woman 13 additional weeks of hormonal exposure compared with a traditional OC that allows a week off each month for menses.

When FDA's Shames was asked if any long-term studies of the effects of permanently suspending menstruation existed, he noted that studies one year in duration that looked at endometrial biopsies for hyperplasia, a marker for endometrial cancer, showed nothing. "We have also asked Wyeth to perform a postmarketing study of serious adverse events, particularly thromboembolic events, to see whether there are any long-term effects that might be different from those of a traditional OC," he remarked.

Lybrel tablets come in 28-day packs and are intended for daily oral use, 365 days a year without stopping. Each tablet contains 90 mcg levonorgestrel and 20 mcg ethinyl estradiol and is not unlike other combination OCs.