FDA to Further Investigate Implantable Devices Containing Certain Metals
Following concerns and reported adverse events linking biological responses to certain types of materials in medical devices, the US Food and Drug Administration (FDA) said recently that it will further engage stakeholders to investigate metal-containing implants and dental amalgam.Part of that engagement will involve a public advisory committee meeting of the Immunology Devices Panel of the Medical Devices Advisory Committee on 13-14 November, which will discuss the associated literature and potential ways to reduce risks.
FDA also released two reports on metal-containing implants and dental amalgam noting that the agency believes “the current evidence, although limited, suggests some individuals may be predisposed to develop a local or systemic immune or inflammatory reaction when exposed to certain metals contained in select implantable devices.”
Recent issues with metal-on-metal orthopedic implants and gynecological metal implants (see more on Essure issues here) highlighted concerns about the potential safety of certain types of metal implants. FDA notes that more frequent “adverse reactions to metal debris” include local responses such as pain, skin rash tissue destruction including bone loss, escape of fluid from the joint, and solid and cystic masses called pseudotumors.
“Systemic responses such as depression, hearing loss, vertigo (dizziness), and neurologic and cardiac damage have also been reported by patients that have metal implants, although the determination of whether the metal caused the event(s) is often not possible,” FDA explains. And while overt implant-related metal toxicity is rare, FDA notes that “elevated serum/blood metal levels represent one of the most frequently reported adverse reactions with potential systemic effects.”
To better understand patient responses to certain metals used in implants and to use that information to improve device safety, FDA said the advisory meeting and other work will look to determine the current state of the science, critical gaps and what approaches FDA should consider moving forward.
“A more systematic research approach incorporating all possible clinical manifestations and underlying pathogenetic mechanisms is needed for enabling a timely detection and preventive treatment of adverse outcomes pertaining to implant reactivity,” the agency notes in the implant report.
But the agency also explains some of the challenges in trying to find connections between the implants and the associated adverse reactions.
“The main challenge in both pre- and post-market phases of regulatory review is the lack of adequate study endpoints and diagnostic and/or prognostic tools which reliably predict clinical responses. The threshold for detecting subtle but consequential biological responses which may constitute signals in our post-market surveillance systems remains to be determined,” FDA says. “Currently, it is extremely difficult to determine whether symptoms are related to the implanted device or other causes. Predictive assessment of the proinflammatory potential and subsequent tissue remodeling remains a major challenge affecting real-world performance of implantable devices and biomaterials. Real world evidence and patient registries may be helpful in this regard.”
The agency also says that lab tests commonly used to diagnose allergy-based sensitivities may not be adequate to identify susceptible individuals.
FDA Report: Biological Responses to Metal Implants
Metals Used in Medical Devices
Dental Amalgam