Although all common birth control pills increase women's chances of getting blood clots, concerns have recently been mounting about an even higher risk linked to a newer generation of pills that contain the compound drospirenone, such as Bayer AG's popular Yaz and Yasmin.
Outside experts advising the Food and Drug Administration on Thursday, in a 21-5 vote, agreed that the current, rather complex label does not adequately help women and doctors understand the risks and benefits of such pills.
(The label) is incredibly hard for physicians to read and if we think that patients are reading these and understanding these before making their decisions, we're delusional," said panel member Dr. Peter Kaboli, associate professor of internal medicine at the University of Iowa Caver College of Medicine.
Nonetheless, in a very close vote of 15 to 11, the panel concluded that benefits of preventing unwanted pregnancies did outweigh the risks.
A number of studies have been conducted on Bayer's Yasmin, the first drospirenone-containing contraceptive to be approved in the United States in 2001. And overall, the evidence is conflicting whether the compound indeed raises the chances of developing potentially fatal blood clots - something that made some panelists reluctant to seek drastic changes to the label.
However, several panel members pointed out that only Bayer-sponsored studies seemed to find Yasmin equally safe as other birth control pills.
"I found that disturbing," said Dr. Maria Suarez-Almazor, a professor at the University of Texas MD Anderson Cancer Center, to applause from numerous women's advocates and patients.
Many of them earlier tearfully recounted sudden deaths and life-changing disabilities they or their loved ones suffered from blood clots they believe were caused by Yaz or Yasmin.
"Most people only see the watered-down label ... We know that labels just don't change behavior," said Cynthia Pearson, executive director of the National Women's Health Network, one of several consumer advocacy groups that argue the drugs should be taken off the market entirely.
FDA's own study earlier this year found that women taking Yasmin were about twice as likely to develop venous or arterial thrombotic events (VTEs and ATEs) than women on older birth control. The risk of VTEs was especially higher in women under 35 while risk of ATEs was higher in women older than 35.
With VTEs, blood clots occur in one of the deep veins in the body, such as the leg or pelvis, and then may travel to the lungs, which could lead to stroke or death.
The FDA study also estimated that 10 in 10,000 women taking the newer drug would get a blood clot per year, compared with about six in 10,000 women taking older contraceptives.
Drawing a definitive conclusion that drospirenone elevates the blood clot risk has been complicated by the fact that the risk also increases if a woman smokes, has extra weight, clogged arteries, a family history or other health problems.
FDA's scientists in their review released on Tuesday suggested that, despite conflicting data, the pills' labels should better reflect all the evidence. The FDA usually follows the advice of its advisory panels.
The FDA study raised a similar concern of a blood clot risk about Johnson & Johnson's Ortho Evra contraceptive patch, which does not contain drospirenone. FDA advisers will discuss Ortho Evra on Friday.
Yaz, a reformulated version of Yasmin, remains one of the U.S. top-selling contraceptives. Bayer raked in $374 million in Yaz sales last year, according to data from IMS Health.
However, that's only about half of what Bayer made off Yaz at the peak of its popularity in 2009. The number of prescriptions filled for the pill also dropped more than by half to 5 million in 2010 from 2009, according to IMS.
Apart from preventing pregnancy, Yaz and Beyaz also have a secondary indication to treat moderate acne and symptoms of premenstrual dysphoric disorder, a severe mood problem.
The company also makes newer Beyaz and Safyral pills, versions of Yaz and Yasmin that add levomefolate to raise levels of folate, which is thought to help fertility.
The current labels for Bayer's family of pills now include a boxed warning that all birth control pills carry, that smoking increases the risk of serious cardiovascular problems, especially in women over 35.
Warnings also highlight higher risk of blood clots associated with birth control pills and present an overview of studies looking at that risk.