FDA OKs 'No-Period' Birth Control Pill
Lybrel Is 1st Oral Contraceptive Designed to Stop Menstruation
Long-Term Safety Questioned
The FDA has asked Wyeth to do a postmarketing study to see if the risk of serious adverse events -- particularly blood clots -- is more common with Lybrel than with traditional contraceptives.
"We don't suspect that there are going to be any surprises in terms of long-term use of this product," Shames says.
Side effects of Lybrel are similar to other low-dose oral contraceptives, including an increased risk of blood clots, particularly in smokers and women over 35, and breakthrough bleeding.
Perhaps more importantly however, cancer experts, like NYU's Julia Smith, MD, are concerned about the lack of long-term data measuring the impact of continuous-use hormones on the risk of breast and other hormone-fueled cancers.
"This is something that has not been carefully studied yet. We don't have any evidence that there is a problem, but we certainly have many instances in the history of medicine where problems only showed up at a much later date after long-term exposure and widespread use," says Smith, director of the Lynne Cohen Breast Cancer Preventive Program at the NYU Cancer Institute.
Moreover, she tells WebMD, "When you tamper with the way the body works naturally you can't predict long-term outcome until you study long-term outcome. And right now we don't have that data."
According to spokeswoman Natalie deVane, Wyeth has conducted large clinical trials evaluating efficacy and safety for one year, with a smaller subset of women followed for a second year. For use beyond that point, they suggest women turn to their doctor for advice.
"We don't have any longer term clinical data, so for women who choose to stay on [Lybrel] longer, like any other oral contraceptive, that's something they should discuss in a conversation with their physician," says deVane.
Lybrel is expected to be available by prescription in July 2007.
With reporting by Miranda Hitti.