WASHINGTON -- The FDA is caught in a tug-of-war between, on one side, thousands of women who believe the Essure permanent sterilization device is dangerous, and on the other, the manufacturer Bayer, which insists that the implant is safe, effective and a "valuable contraceptive option."

Recently, members of Congress and an independent research body entered the fray.

Essure is intended for women who have decided not to have any, or any more, pregnancies.

Once inserted in a women's fallopian tubes, the device, made of an expandable nickel-titanium coil with a stainless steel coil inside it, triggers tissue growth, ultimately blocking these tubes and preventing sperm from entering the duct. At least, that is how it is intended to work.

But thousands of adverse reports have been filed with the FDA, delineating complaints such as abdominal pain, bleeding, uterine perforations -- and device failure leading to pregnancy. Lawsuits against Bayer involving Essure number in the thousands as well. (For a timeline of major events in Essureâs product life, click here.)

In September, Bayer announced it would stop sales of Essure outside the U.S. for "commercial reasons," telling MedPage Today "there is not as much patient interest in permanent birth control" elsewhere in the world.

Essure's critics remain skeptical.

In late October, House Democrats sent a letter to FDA Commissioner Scott Gottlieb, MD, blaming the agency for letting Bayer "drag its feet" on a post-market study of the "dangerous" permanent sterilization device.

"This device is a prime example of systemic medical device oversight shortfalls and insufficient enforcement to ensure the safety and efficacy of medical devices," wrote Rep. Rosa DeLauro (D-Conn.) , Rep. Jan Schakowsky (D- Ill. ) and Rep. Louise Slaughter (D- N.Y.).

They demanded that the agency use "enforcement measures" to compel Bayer to finish its study in a "timely fashion" they wrote, "so the risks associated with the Essure device will be documented and made public."

While the letter stated "only one patient has been enrolled," FDA and Bayer said the study had 136 participants as of Oct. 19, 2017.

The Democrats' letter, dated Oct. 30, 2017, also charged that in more than half of the 18,000 reported adverse events associated with Essure implants, women needed invasive surgery to remove the device due to "pregnancy, auto-immune disease, and device migration leading to organ and tissue perforation," and "many women" received full hysterectomies.

This point was not disputed by Bayer. However, the drugmaker underscored one line from the agency's website: "The FDA continues to believe that the benefits of the device outweigh its risks, and that Essure's updated labeling helps to assure that women are appropriately informed of the risks."

On the agencyâs website, the FDA notes that adverse event reports are one of many channels the agency uses to monitor a deviceâs safety.

âWhile such reports are a valuable source of information, this type of reporting system has notable limitations, including the potential submission of incomplete, inaccurate, untimely, unverified, or biased data.â

DeLauro, Schakowsky, and Slaughter demanded a meeting with the commissioner "within the next month."

FDA Commissioner Scott Gottlieb, MD, told MedPage Today on Nov. 3 that he planned to meet with the congresswomen. Asked whether the agency intended to take Essure off the market Gottlieb said, "We continue to look at that."

As of this writing, DeLauro's office said no one from the FDA had yet been in contact on the issue. An FDA press representative told MedPage Today that the agency still plans to set up a meeting with the legislators.

In an email to MedPage Today, Courtney Mallon, deputy director of Bayer's US Pharmaceuticals Product Communications, said the congresswomen's letter "unfairly and untruthfully maligned" its product and that it has met "every milestone" of its post-market study.

"As FDA has repeatedly determined -- after a rigorous review of the scientific evidence -- Essure is a safe and effective medical device that benefits women by providing them with a valuable contraceptive option."

"Bayer has and will continue to fully support the use of Essure in the U.S., and will continue to provide physicians the training and tools they need to appropriately counsel women and support the safe and effective use of the product."

An FDA press representative highlighted the "Postmarket Surveillance Studies" page for Essure, which outlines the "open-label, non-randomized, prospective observational cohort study" comparing Essure and laparoscopic tubal sterilization, and notes the 136 current participants at 44 study sites.

"The FDA believes clinical data will help us to better understand certain patient complications that have been experienced by women who have Essure permanent birth control when compared to women who undergo tubal ligation," the agency official said.

Essure's Beginnings

The Essure System received FDA approval in November 2002. It was then manufactured by Conceptus Inc., which was acquired by Bayer in 2013.

On first blush, the device appeared to have significant advantages over alternatives. No anesthesia. No incisions. No long recovery period.

In fact, the American College of Obstetricians and Gynecologists (ACOG) highlighted other benefits of a hysteroscopic (via the uterus) sterilization, in a 2016 comment letter regarding draft guidance on Essure and similar devices.

"Because the hysteroscopic approach does not require entry into the abdominal/peritoneal cavity, major morbidity associated with general anesthesia and abdominal surgery can be avoided," the group stated. It added that hysteroscopic sterilization could also benefit women who might be contraindicated for abdominal surgery, such as obese patients, those with serious co-existing medical conditions or scar tissue from previous surgeries.

"ACOG considers it essential that less invasive tubal occlusion options, like Essure, remain available to women, and that women have access to accurate scientific information on the risks and benefits," the letter said.

Aileen Gariepy, MD, MPH, of Yale School of Medicine, told MedPage Today that ob/gyns were initially excited about the prospects of a less invasive permanent sterilization technique.

"I think in retrospect, we were too excited," she said.

Gariepy is the principal investigator of an independent study comparing hysteroscopic and laparoscopic sterilizations, sponsored by the Patient-Centered Outcomes Research Institute (PCORI).

Essure was advertised as non-surgical, non-hormonal, and 99% effective, Gariepy said.

It was also marketed as a "natural" option, because it's the woman's own tissue growth over time, triggered by the device, that seals the fallopian tubes, she explained.

For clinicians, it sounded simpler, more direct, said Gariepy, who described laparoscopic sterilization as "like going through the chimney." With Essure, "you're kind of going through the front door," she said.

Gariepy said she's performed about 50 Essure implants, with disappointing results: the device brought "more steps, more problems."

Essure placement involves the following:

Inserting a camera through the cervix

Identifying the opening of each fallopian tube

Threading a catheter through the tubes, leaving behind a coil in each one

Keeping the patient on alternative birth control for 3 months

Performing an x-ray at 3 months to ensure coils are in place

Injecting x-ray contrast agent into the uterus to confirm complete blockage

At each stage, there are challenges, Gariepy explained.

Clinicians may have trouble visualizing the opening of the fallopian tubes, the tubes may be scarred from previous infection and can spasm, and/or the clinician may use too much force and pierce the coil through the tube. After 3 months, a clinician may find a coil has fallen from the fallopian tube to the intrauterine cavity. Some women have reported pregnancy between the date of implantation and the 3-month confirmatory test.

She told MedPage Today that she has done few Essure placements in recent years because most of her patients choose laparascopic sterilization "after counseling about all the pluses and minuses of all options."

She added, "there's a need for better data, and there's an opportunity to do better."

Not Just Unsafe but Ineffective?

Olympian skier Picabo Street publicly announced her own Essure procedure in 2010. Later that year, she announced she was pregnant, Gariepy noted.

The reports of device failure stand in contrast to post-approval studies completed in 2008 that found no Essure recipients became pregnant. Thirty-two women reportedly had the Essure device removed.

Earlier trials were funded by industry, Gariepy said. Instead of comparing Essure to laparoscopic sterilization in head-to-head studies, they used decades-old historical controls from the Collaborative Review of Sterilization Techniques (CREST) study, she noted.

Researchers reported their conflicts of interest but used only the "best case scenarios"and peer reviewers overlooked their methodology.

"The way they got to that number [the 99% success rate] is by shaving people off the denominator," she said: women in whom a coil fell out or in whom the camera couldn't properly be inserted were simply excluded.

Gariepy's own research, using a theoretical model, found a 15% chance that women's fallopian tubes would not be completely blocked after 3 months.

"If 85% of women can be sterilized, that's not bad. It's just that women need to know that number and choose for themselves," she said.

"I think that what's happened to Essure is not unique to this one product. This is a much bigger problem at the FDA and is related to the FDA's failure to provide good studies of medical devices," Diana Zuckerman, PhD, president of the National Center for Health Research, told MedPage Today in a phone interview, speaking of the need for more comparative effectiveness research.

Zuckerman is a member of the PCORI-funded study team alongside Gariepy.

"We know that many women have been harmed by Essure. The question is, are there patients for whom Essure is a better idea than the alternatives?" she said.

In September 2015, the FDA asked an advisory committee to review the data on Essure. The panel made a series of recommendations to improve the knowledge base and communications with patients; it was not asked to vote on whether the device should remain on the market.

Zuckerman spoke at the meeting, telling the panel that Conceptus manipulated the research and re-wrote patient responses.

The consumer group Public Citizen called for the device's removal at the meeting, saying the device "wasn't adequately studied" before it was approved.

"When you look at information that was available in subject-level records to monitor [adverse events] there were [adverse events] that were occurring that weren't ultimately reported in the published literature," said Michael Carome, head of Public Citizen's health division, in a recent interview.

However, an ACOG spokesperson told the committee in 2015 that it was critical for women to have choices in contraception. ACOG called for more data collection on safety and efficacy, including development of a comprehensive patient registry -- as did other witnesses and panel members -- but the FDA did not pursue it.

Planned Parenthood also backed keeping Essure available as a contraceptive option "after adequate counseling."

Since that advisory committee meeting, more adverse event reports have accumulated, with the number citing "deaths" associated with Essure reaching 38 as of Dec. 31, 2016. However, in a review posted Sept. 29, 2017, the agency counted only four adult deaths, plus 18 incidences of "pregnancy loss" and two infants who died after birth. Other reports were duplications or misclassified, they said.

"Confirming whether a device actually caused a specific event can be difficult based solely on information provided in a given report," the agency stated in the review.

The PCORI-funded study of Essure versus laparoscopic sterilization will examine California's Medicaid claims data from 2008-2013. They will calculate successful sterilization rates, additional surgeries due to complications, and instances of chronic pain, depression, allergies, immune syndromes and substance use.

Nearly 9,000 women given Essure and over 14,000 women who had laparoscopic sterilizations are expected to be included in their study, and Gariepy said she expects preliminary results in the spring of 2019. The project is scheduled to conclude in July 2020, according to PCORI's website.

The final report for Bayer's study is slated for September 2023.