By: Jeff Shuren, M.D., J.D., Director, Center for Devices and Radiological Health (CDRH) and Ed Margerrison, Ph.D., Director, Office of Science and Engineering Laboratories, CDRH
Progress in science and technology offers extraordinary opportunities to develop innovative medical products that can save lives and lead to better treatments, better diagnostics and better care for patients. The U.S. Food and Drug Administration is committed to advancing the public health by helping to bring innovative technologies to market and assuring that medical devices already on the market continue to be safe and effective.
As the rate of technological advances moves faster than the science for evaluating the benefits and risks of new products, the FDA’s Center for Devices and Radiological Health (CDRH) is helping to ensure that device developers have the right test methods to evaluate new innovations. The Catalog of Regulatory Science Tools collates a variety of regulatory science tools that CDRH’s Office of Science and Engineering Labs (OSEL) has developed, with new tools added as they become available. These methods expand the scope of innovative science-based approaches to improve the development and assessment of emerging medical technologies. The catalog includes more than 100 tools, including laboratory methods, tissue-mimicking phantoms, and computational modelling and simulations.
Why Regulatory Science Tools in Addition to Standards and MDDTs?
The FDA recognizes voluntary consensus standards to facilitate meeting requirements under statute or regulations. The use of FDA-recognized consensus standards can increase predictability, streamline premarket review, provide clearer regulatory expectations, facilitate market entry for safe and effective medical products, and promote international harmonization. However, standards take a long time to gain consensus and often are not approved until the particular medical device category is well-established, which means that early developers do a lot of the “heavy lifting.”
The FDA's Medical Device Development Tools (MDDT) program is a way for the FDA to qualify tools that medical device developers can use in the development and evaluation of medical devices. Qualification means that the FDA has evaluated the tool and concurs with available supporting evidence that the tool produces scientifically-plausible measurements and works as intended within the specified context of use. (The list of qualified MDDTs can be found on FDA.gov.) Although the MDDT qualification program is not meant to replace the consensus standard development and recognition process, the FDA views the MDDT qualification program as a complementary program for evaluating and recognizing tools that are useful for medical device evaluation and to support regulatory decision-making.
The Catalog of Regulatory Science Tools provides a peer-reviewed resource for companies to use where standards and MDDTs do not yet exist. The tools reduce the need for device developers to design ad-hoc test methods and allow them to focus their limited resources on how well their new product works, not how well it may be tested. Ad-hoc testing can slow the process of bringing innovative devices to market because the developer must develop and validate a testing methodology in addition to developing a new product. As a result, the FDA must then assess both the testing methodology on a case-by-case basis to ensure the tests are fit for purpose, as well as the new product. It is therefore of great benefit to both innovators and regulators to use a common set of methodologies wherever possible, and over time we would expect the most useful regulatory science tools to progress through the qualification process to become fully fledged MDDTs. These methodologies complement FDA-recognized standards and qualified MDDTs. They represent an important contribution to reducing risk in all stages of product development and are particularly important to the early inventors and innovators, who often don’t have the means to evaluate their systems. In addition to helping device developers identify appropriate tools for their needs, the catalog entries include detailed instructions for use and, where appropriate, reference to the original peer reviewed source for further detail.
Case Study: Photoacoustic Imaging (PAI) - an Emerging Hybrid Technology
PAI is an emerging hybrid technology that combines lasers with ultrasound equipment to enable deep, noninvasive mapping of blood vessels and blood oxygen saturation (SO2). PAI has broad potential applications in oncology (especially breast cancer detection), surgical guidance, vascular imaging, and oximetry. Despite rapid growth and investment in academia and industry, the availability of commercial systems for research use, and the strong potential of this technology to improve patient care, no PAI standards exist yet. Device innovators are left to develop and validate their own test methods, which can cost valuable time and resources.
To address this need and speed up the development and translation of PAI devices, an interdisciplinary team in OSEL developed novel “phantoms,” which are objects that approximate imaging device behavior in real tissue, as well as associated test methods for assessing PAI device performance (such as image quality, blood vessel detectability, and oximetry measurement accuracy). These phantoms contain imaging targets representing blood vessels of varying size, hemoglobin concentration, and SO2, embedded within a tunable background material that can mimic light and sound transport in different tissues (such as breast tissue with varying density). Developers can use these phantoms to quantify PAI device performance for a range of clinically relevant scenarios in a more controlled and well-characterized environment than in animals or human subjects.
Through this work, the FDA’s regulatory science program has developed a well-characterized set of PAI performance test methods that can support many stages of the product lifecycle, including research and development, design evaluation and optimization, quality systems, acceptance testing, constancy testing, and user training. The FDA has taken several steps to foster use of these test methods by the PAI community, including patenting and licensing the developed tissue-mimicking material to an imaging phantom manufacturer to provide a high-quality commercial source for these phantoms.
This work also provides a foundation for future PAI standards and consensus test method development through the recently formed International Photoacoustics Standardisation Consortium (IPASC), a working group of over 100 experts from academia, industry, and government, including the FDA.
Advancements in technology and medical device innovation will continue to improve the health and well-being of patients. By staying a step ahead and understanding the science that supports these advances, the FDA will continue to spur innovations while ensuring that devices are safe and effective. Regulatory science tools, like the PAI phantoms and others found in the FDA’s Catalog of Regulatory Science Tools, can help device makers develop their products faster and with increased confidence in the regulatory process. Ultimately, these tools can play a key role in accelerating patient access to innovative, safe, and effective medical devices.