Materials
“Fortunately, or unfortunately, there are not that many materials that have been vetted through to clinical success, so there are relatively few to choose from, whether we are talking about plastic or metal,” says Ryan Siskey, corporate vice-president and director of US offices and laboratories at engineering and scientific consultancy Exponent. “Bioactivity has not been assessed for many, and there have not been many innovations.” For many Class II devices subject to a 510(k), the manufacturer must demonstrate substantial equivalence to a legally marketed predicate device. The comparison is not necessarily with the best device on the market, nor is ‘do no worse’ the statutory test. When a new device has different technological characteristics, the manufacturer must show it is as safe and effective as the predicate and does not raise new questions of safety and effectiveness. “If you don’t have that, you are starting from a weaker position,” warns Siskey. “For more investigational devices, you have to run a multimillion-dollar clinical trial, so costs increase by orders of magnitude. As a result, developers will
“The consequence of leaving approval issues too late is potentially flushing millions of dollars down the drain with nothing to show for it.”
Ryan Siskey
probably select a material that has a strong regulatory foundation.”
Clinical evidence requirements and costs vary by device type, risk, indication and study design. Late-stage materials changes certainly come with a cost. Supplier or formulation changes, resin substitutions, PFAS-related reformulations and their impacts on submissions and validation may be costly. Siskey, who frequently analyses the trade- offs between device performance, manufacturability and biological safety, recommends acting early. “The consequence of leaving approval issues too late is potentially flushing millions of dollars down the drain with nothing to show for it,” he says. “You have to think like a hurdler at a track meet – the design process, regulatory approval, scaling up of manufacturing and gaining clinicians’ confidence are all hurdles you must overcome. The regulatory hurdle is not the biggest if you are gathering good data or using approved materials.” The FDA does not approve materials independently of a finished device and intended use, although prior clinical use and relevant material information may help support a submission. So, is design for approval stifling innovation?
Priorities in balance Materials have changed over time and will 70
undoubtedly continue to evolve. Designing for approval may put the brakes on that train of development, but that may not be new. “There has always been the thinking that using a material with a long and successful history will simplify the regulatory process, and that has inhibited the advancement of innovative biomaterials,” says Ratner. “If the FDA has a master file on the materials you want to use, then the process is simpler. I am not sure we are in this age of ‘design for approval’ because you want a device to have optimal performance, but if you can do that with FDA recognised materials that is easier.” Information in a device master file may support a submission where the file holder authorises FDA to refer to it, but this does not amount to approval of the material itself.
Rollins also recognises that there is more caution, but does not see an unwillingness to innovate. A material with an established clinical history gives the manufacturer a stronger starting point, and novel materials need a strong value proposition. Still, if a new material provides a meaningful improvement in clinical performance, durability, infection resistance, patient comfort or manufacturability, the additional development burden may be fully justified.
“This is not about allowing regulatory requirements to control innovation,” he states. “It is about understanding the risks early enough that the development team can make informed decisions rather than discovering expensive problems when the design is already locked in. FDA guidance and the ISO 10993 framework both reinforce that biological evaluation should be integrated into a risk- management process rather than treated simply as a list of tests performed at the end of development.” “If devices using novel materials are safer in the long run, the technology may have a higher likelihood of making a big difference in clinical outcomes, but if you want to rock the boat, then the capital investment required is going to be large,” says Siskey.
AI-supported materials screening, digital materials libraries, sustainability considerations, PFAS-related regulatory developments and differences between US and EU requirements may influence future materials decisions. Indeed, Rollins foresees a big change in the ability to understand and predict how materials behave through better analytical chemistry, computational toxicology, advanced imaging, degradation modelling and AI, enabling developers to connect material composition with patient exposure and biological response much earlier in development. Performance is essential for new medical devices, but the best material is not necessarily the one with the highest performance metrics. Increasingly, it may be the one that also reduces regulatory uncertainty. ●
www.medicaldevice-developments.com
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