FDA has finalized its guidance on characterization of ultrahigh molecular weight polyethylene, or UHMWPE, used in orthopaedic devices.
The text is intended to help manufacturers understand what data to submit when seeking clearance to sell certain Class II and III devices, including spinal implants.
FDA has retained the structure of the draft guidance it published in 2016 but has rewritten large sections of the text, in some cases to bring it in line with feedback from the trade group AdvaMed.
Manufacturers have used UHMWPE as a biomaterial in devices like knee and hip replacements for decades. Over that time, companies have developed highly cross-linked UHMWPE and added antioxidants to the material to reduce its wear rate to extend the lifespan of the devices.
In 2016, FDA published draft guidance describing the different types of UHMWPE then available and set out how it expected manufacturers to characterize the materials before filing for clearance to sell devices featuring them in the U.S.
The industry was broadly supportive of the requirements detailed in the document and urged FDA to bring it into force after clarifying and correcting some points, with AdvaMed asking the agency to “finalize this draft guidance as promptly as possible” as it put forth many “substantive requirements.” AdvaMed made that comment three years ago.
In the lag between the publication of the draft and final documents, FDA has rewritten large parts of the guidance, in some cases to address the points raised by AdvaMed in its feedback.
As AdvaMed requested, the guidance now covers the use of all antioxidants, not just vitamin E, in UHMWPE, features a revised definition of the conventional form of the material and offers different advice on the shelf life of the polyethylene.
In many cases, FDA has gone beyond the changes recommended by AdvaMed and provided far more information than was in either its original draft or the feedback it received. For example, the shelf life section of the final guidance is around 10 times as long as that of the draft, enabling FDA to provide more detailed advice on topics including stability testing and package integrity.