FDA Raising Questions About Safety Of Nitinol, Alloy Used In Essure And Other Medical Implants

Federal health regulators indicate that manufacturers need to exercise extra caution with certain medical devices, due to side effects of exposure to a metal alloy called nitinol, which has been linked to reports of problems with Essure birth control implants and other devices.

On April 19, the FDA issued a draft guidance (PDF) on assessing medical devices containing Nitinol, an alloy made of nickel and titanium.

The guidance is aimed at the medical device industry and FDA staff, and includes recommendations on what the FDA is looking for in device approval submissions for medical devices containing the metal.

The agency has established what manufacturers should submit as far as testing for corrosion, biocompatibility, and performance under conditions of stress, strain and different temperature. It also lays out guidance for label warnings about potential allergic reactions to the metal and other information.

The guidance comes amid what appears to be growing concerns about nitinol problems in certain medical devices, particularly implants. Nitinol is used in many medical devices; including wires, stents, surgical instruments, orthopedic fracture fixation devices, and transcatheter heart valves. Many of those devices have been linked to adverse tissue responses which health experts had difficulties explaining or confirming.

The FDA notes that it was also used in the Essure birth control implant, which was removed from the market in December following years of reports of adverse events including fracturing and migration, but also of mysterious ailments and claims that women’s bodies had what appeared to be allergic reactions to the device.

“Nitinol has unique properties that have led to an increase in its use in devices – particularly for orthopedic fracture fixation, cardiovascular stents, guidewires and other devices used in minimally-invasive medical procedures,” Dr. Jeffrey Shuren, director of the FDA’s Center for Devices and Radiological Health, said in a press release. “Devices made with nitinol provide many important benefits to patients, but we need to be able to assess whether, among other things, there are any health risks when the material comes into contact with various parts of the body for extended periods of time.”

Essure Problems

Although Essure was recalled from the market in most countries in 2017, Bayer continued to sell the device in the United States until the end of last year. Amid mounting pressure and publicity about the injuries women were experiencing from Essure, the company announced in July 2018 that it was removing Essure from the US. market on December 31, 2018.

Following the decision, the FDA confirmed that Bayer would be required to extend a post-market surveillance study and take other measures to ensure long-term Essure oversight well after production and sales have ceased.

FDA officials have reported that the agency received about 12,000 adverse event reports related to the Essure birth control implant last year. In April, the FDA made changes to Essure’s premarket approval, requiring both doctors and patients to sign off on a checklist of potential Essure complications.

In November 2016, following controversial hearings in the U.S., where testimony was heard from large numbers of women and medical experts, the FDA decided not to recall Essure in the United States. However, the agency did require Essure black box warnings, which are the strongest that the FDA can require a medical device carry.

Approximately 750,000 women worldwide have been implanted with the device, and Bayer has previously estimated that 70% of those have been implanted in women in the U.S.

Bayer currently faces more than 18,000 product liability lawsuits filed nationwide, each involving similar allegations that side effects of Essure coils caused women to experience painful and debilitating complications after receiving the birth control device.

The manufacturer has reportedly spent about $413 million defending the litigation over the last year, and may face substantially greater liability at trial if Essure settlements or another resolution for the cases is not reached.