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By Colette Bouchez
WebMD Health News
Reviewed By Louise Chang, MD
However, women using Lybrel will most likely have unplanned breakthrough bleeding or spotting, according to the FDA.
Women should consider Lybrel's no-period convenience vs. the chance of having breakthrough bleeding or spotting, notes Daniel Shames, MD, deputy director of the Office of Drug Evaluation III at the FDA's Center for Drug Evaluation and Research.
"I think each woman and her health care provider will have to look at the data, which we have explicitly defined in our labeling, and decide if this form of contraception is appropriate for her," Shames told reporters at a news conference.
This newest form of birth control, developed by Wyeth Pharmaceuticals, contains 90 micrograms of levonorgestrel and 20 micrograms of ethinyl estradiol -- a combination similar to that found in other low-dose oral contraceptives. The difference here: Lybrel replaces the four- to seven-day placebo pill with continuous daily dosing for nonstop birth control with no menstrual periods.
"Wyeth developed this contraceptive so that women may have an additional option to manage their cycles. The studies to support this product are a reflection of our longtime commitment to innovation in women's health," said Ginger Constantine, Wyeth's vice president of Women's Health Care and Bone Repair, in 2005 when the new drug application was made.
The FDA approved Lybrel based on two clinical trials, each lasting for one
year, of more than 2,400 women aged 18-49.
The trials showed Lybrel to be a safe and effective contraceptive when used as directed.
Lybrel's labeling provides information on breakthrough bleeding and spotting.
"Many of the women that had bleeding or spotting dropped out" of the clinical trials, Shames says. "By the end of the study, only half of the women were in the study."
Of the women who started the clinical trials, "maybe 30% or 35% had no bleeding or spotting" after 13 cycles (about a year), says Shames.
The other women experienced sporadic bleeding or spotting that diminished with time, Shames notes.
"Women are going to have to decide whether they want to begin this experience, and understand that it's going to take them a while before they perhaps get to where they want to be, which is having no bleeding or spotting," Shames says.
As with other low-dose contraceptives, "you need to be sure to use some other form of contraceptive if you find you've missed a pill or forgotten a pill," says Shames.
Eliminating Menstrual Cycles
While Lybrel is the first oral contraceptive designed to completely stop menstruation, Steve Goldstein, MD, says that's not as dramatic as it sounds. Understanding how the menstrual cycle works helps to understand why.
Normally, says Goldstein, a rise in hormones linked to ovulation causes the lining of the uterus to thicken in anticipation of a fertilized egg. If fertilization does not occur, hormone levels drop and the lining is shed in the form of menstrual blood. Oral contraceptives, however, change that activity.
"The pill shuts down your normal hormone production and replaces it with a very tiny amount, so there is no buildup of the uterine lining," says Goldstein, a professor at NYU Medical Center in New York City. Without a lining, there is no shedding, so the bleeding that occurs when you stop the pill is a "withdrawal bleed caused by a drop in hormones," explains Goldstein.
Goldstein tells WebMD that the monthly bleeding that occurs during pill use is unnecessary, so avoiding it -- the way you can with Lybrel -- should have no impact on health. Moreover, Goldstein says the menstrual cycle and fertility should return soon after stopping this pill, much the way it does with other oral contraceptives.
In at least one study conducted by Wyeth and presented at the 2006 annual meeting of the American College of Obstetricians and Gynecologists, 99% of 187 women taking Lybrel for one year either returned to menstruating or got pregnant within 90 days after stopping the drug.
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.
SOURCES: Daniel Shames, MD, deputy director, Office of Drug Evaluation III, Center for Drug Evaluation and Research, FDA. Steve Goldstein, MD, professor, obstetrics and gynecology, NYU Medical Center, New York City. Julia Smith, MD, director, Lynne Cohen Breast Cancer Preventive Program, NYU Cancer Institute, New York City. Natalie deVane, spokeswoman, Wyeth Pharmaceuticals. Archer, D.F. Contraception, December 2006; vol 74: pp 439-445. Wyeth's New Drug Application for New Oral Contraceptive With Uninterrupted Dosing Regimen Accepted for Filing at FDA. News releases, Wyeth Pharmaceuticals. News release, FDA.
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