On May 10, the U.S. Food and Drug Administration (FDA) issued draft guidance to provide its initial thoughts on regulatory requirements for additive manufactured (AM) devices, a category that includes three-dimensionally (3D) printed medical devices. Additive manufacturing enables companies to more easily design and create devices with complex or delicate internal structures. Because AM can use data derived from a patient's medical imaging to produce unique anatomically matched medical devices, the method holds promise to advance the field of personalized medicine. The draft guidance proposes a risk-based approach to the unique regulatory challenges posed by additive manufacturing, including point-of-care manufacturing. FDA's "leap-frog" draft guidance provides technical considerations for the design and testing of devices that include at least one AM step. Leap-frog guidances are a relatively new mechanism used by the Center for Devices and Radiological Health to share initial thoughts regarding emerging technologies that are likely to be of public health importance early in product development. To date, AM has been used for a number of medical devices, primarily in orthopedic device types such as joint replacements, cranio-maxillofacial implants and devices used in guided surgery. The draft guidance does not address specific device types, but FDA notes that AM devices generally will be subject to the same regulatory requirements as those to which a non-AM device of the same type is subject. Although the draft guidance was issued jointly by the Center for Devices and Radiological Health and the Center for Biologics Evaluation and Research, it explicitly does not address the incorporation of biological, cellular or tissue-based products. During the AM process, an object is constructed by repetitively layering materials under computer control. The technique allows device manufacturers to more easily manufacture "patient-matched" devices, modify a device's shape or size without retooling or altering manufacturing equipment, make complex or delicate devices as a single piece or create uniquely textured or porous devices. The draft guidance notes that Quality System requirements will depend on factors such as whether the device is an implant or is load-bearing and provides recommendations for both standard-size and patient-matched device designs. Designs for patient-matched devices in particular should account for whether the medical imaging techniques are accurate and appropriate for the target anatomical location. To the extent a patient-matched device is made by altering the features of a standard-size device, manufacturers should apply safeguards to prevent uses that exceed the FDA-cleared specifications.
Software is particularly important to AM processes because it involves interaction among multiple software packages from object design through the object build. For example, medical imaging software, if for a patientspecific device, must be able to communicate with the AM design and manufacturing software. As with non-AM devices, all software used in the manufacture of AM devices must be validated according to an established protocol. AM may also require special cleaning and sterilization validation processes due to the complex geometry the technology makes possible.
Besides Quality System recommendations for the design and manufacture of AM devices, the draft guidance includes device testing considerations that FDA recommends as part of a premarket submission for a device made with AM. Manufacturers should include a thorough description of the AM device and the results of mechanical performance testing that takes build-space effects into account. For example, the strength of materials made with certain types of AM technology may depend on how far the material is from the energy source during the layering process or on the orientation of the object during layering. FDA also recommends that manufacturers provide information about the device materials' chemical and physical properties because the iterative melting and solidification processes could weaken or otherwise affect polymers in unexpected or undesirable ways, posing unintended health risks. Manufacturers should also be able to demonstrate consistency and reproducibility.
With respect to labeling, the draft guidance notes that AM devices should follow existing applicable labeling regulations, guidance documents and consensus standards. FDA recommends additional labeling information for patient-matched devices: a patient identifier, details identifying the device's intended use and the final design iteration or version used to produce the device. Expiration dating may depend on events that might change the patient's anatomy, so labeling should also include a precaution that the patient should be assessed for these changes before use.
Public comments on the draft guidance are due on August 8.