In the first large, controlled study of Bayer AG's sterility device Essure, researchers found that women who have had it implanted were 10 times as likely to need new operations as women who got standard sterility surgery.
Women have spoken of debilitating pain and allergic reactions to the Essure implants, including at a Food and Drug Administration workshop last month. Some 750,000 or more women world-wide have gotten the Essure implants, but it has been difficult to assess the scope of the problem until this study.
"A more than 10-fold high occurrence of reoperation during the first year following Essure-based surgery is a serious safety concern," wrote researchers from Weill Cornell Medicine.
Bayer said Tuesday that "Essure is a highly effective birth-control option with a positive benefit-risk profile for women who have completed their families and want permanent contraception with a nonsurgical procedure." It said that more than a decade of research, development and real-world experience "supports the safety and efficacy of Essure."
Essure implants are inserted through the vagina and cervix into a woman's fallopian tubes. There, they are designed to cause inflammation and fibrous tissue growth that will block the pathway between sperm and egg.
Reoperations don't always connote a safety issue, but the doctors in the study noted that "most of the adverse events" reported by a federal device safety database "were injuries that would require a reoperation." Severe pelvic and abdominal pain, and allergic reactions to nickel in the device, have been commonly reported.
The report was statistically powerful, as it included the records of 8,048 women who underwent the Essure procedure, and 44,278 others who got traditional surgery, known as tubal ligation. The researchers evaluated the cases of patients with such procedures in New York state between 2005 and 2013. Reoperations one year afterward were the main outcome measured.
The study, run by Art Sedrakyan of Weill Cornell, appeared online in the publication BMJ.
The FDA now is considering the safety record of the device after receiving a wave of recent complaints?2,259 in 2014 and 1,363 through June 1, 2015.
Bayer acquired Essure through a 2013 acquisition of Conceptus Inc., the original maker of the product.
This product poses the latest challenge for the medical-device center at the FDA, which never insisted on a gold-standard, randomized and controlled study prior to approving the device. Often, as was the case with devices like metal-on-metal hip joints that sometimes failed, the FDA has used an abbreviated process requiring only that the new device be substantially like an older one.
Essure's approval was different. It was in the most stringent FDA category of medical devices when the FDA approved it in 2002?which often can mean a strenuous clinical study is called for. But the agency didn't require that this study include a control, or comparison group of patients who didn't get the device, a fact that was sharply criticized by some panelists at the workshop in September. Agency officials noted that the preapproval study did include 600 patients and said it required Essure's maker to do further study after approval.
There have been some lawsuits filed over Essure, but lawyers said their numbers are small, largely because of a 2008 Supreme Court decision called Riegel v. Medtronic. That case said that because the FDA oversees the safety of medical devices, plaintiffs generally are pre-empted from suing device makers under state laws.
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