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Medical regulators take a closer look at 3D printing

Additive manufacturing garners more scrutiny as use of 3D printing in medicine expands

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The Pew Charitable Trusts recently published an issue brief about the growing use of additive manufacturing to produce medical devices and how the Food and Drug Administration must ensure the safety of these devices for patients. Following is an edited excerpt from the brief, titled What Is Medical 3D Printing—and How Is it Regulated? — Ed.

Advances in 3D printing are drawing more attention in the health care field because of the technology’s ability to improve treatment for certain medical conditions. A radiologist, for instance, could create an exact replica of a patient’s spine to help plan a surgery. A dentist can scan a broken tooth to make a crown that fits precisely into the patient’s mouth. In both instances, the doctors use 3D printing to make products that specifically match a patient’s anatomy.

The technology is not limited to planning surgeries or producing customized dental restorations, however. 3D printing has enabled the production of customized prosthetic limbs, cranial implants, and orthopedic implants such as hips and knees. At the same time, its potential to change the manufacturing of medical products—particularly high-risk devices such as implants—could affect patient safety, creating new challenges for Food and Drug Administration (FDA) oversight.

To date, most FDA-reviewed products developed via 3D printing have been medical devices like orthopedic implants. Such a manufacturing approach offers several clinical advantages. Devices with complex geometries such as knee replacements, for example, can be 3D-printed to feature a porous structure that facilitates tissue growth. 3D printing also provides the ability to produce a whole product or component at once while other manufacturing techniques may require several parts to be fabricated separately and screwed or welded together.

How AM is Regulated

The FDA does not regulate 3D printers; it regulates the medical products made via 3D printing. The type of regulatory review required depends on the kind of product being made, the intended use of the product, and the potential risks posed to patients.

FDA classifies devices based on their level of risk and the regulatory controls necessary to provide a reasonable assurance of safety and effectiveness. Class I devices are low risk and include products such as bandages and handheld surgical instruments. Class II devices are considered moderate risk and include items such as infusion pumps, while Class III devices, which are considered high risk, include products that are life-supporting or life-sustaining, substantially important in preventing impairment of human health, or present an unreasonable risk of illness or injury. A pacemaker is an example of a Class III device.

All devices, unless specifically exempted, are expected by FDA to adhere to current good manufacturing practices, known as the quality-system regulations, which are intended to ensure a finished device meets required specifications and is produced to an adequate level of quality.

Specific guidance from the FDA does not yet exist for 3D printing in the drug or biologic domains. These products are subject to regulation under existing pathways through FDA’s Center for Drug Evaluation and Research or the agency’s Center for Biologics Evaluation and Research.

In 2017, former FDA Commissioner Scott Gottlieb said that the FDA planned to review the regulatory issues associated with bioprinting to see whether additional guidance would be necessary outside of the regulatory framework for regenerative medicine products. To date, no subsequent updates on this review have emerged.

FDA Oversight Challenges

3D printing presents unique opportunities for biomedical research and medical product development, but it also poses new risks and oversight challenges because it allows for the decentralized manufacturing of highly customized products—even high-risk products such as implantable devices—by organizations or individuals that may have limited experience with FDA regulations.

The agency is responsible for ensuring that manufacturers comply with good manufacturing practices and that the products they create meet the statutory requirements for safety and effectiveness. When used by registered drug, biologic, or device manufacturers in centralized facilities subject to FDA inspection, 3D printing is not unlike other manufacturing techniques. With respect to 3D printing of medical devices in particular, FDA staff have stated that “[t]he overarching view is that it’s a manufacturing technology, not something that exotic from what we’ve seen before.”

However, when 3D printing is used to manufacture a medical product at the point of care, oversight responsibility can become less clear. It is not yet apparent how the agency should adapt its regulatory requirements to ensure that these 3D-printed products are safe and effective for their intended use. The FDA does not directly regulate the practice of medicine, which is overseen primarily by state medical boards. Rather, the agency’s jurisdiction covers medical products. In some clinical scenarios where 3D printing might be used, such as the printing of an anatomical model that is used to plan surgery, the distinction between product and practice is not always easy to discern.

In recognition of this complexity, FDA’s Center for Devices and Radiological Health is developing a risk-based framework that includes five potential scenarios in which 3D printing can be used for point-of-care manufacturing of medical devices.

What Is Medical 3D Printing—and How Is it Regulated? can be read in its entirety at Pew’s website.