FDA Finalizes Guidance on Medical Product Classification
On September 26, 2017, FDA announced in a Federal Register notice the availability of the final guidance document, Classification of Products as Drugs and Devices & Additional Product Classification Issues. This guidance provides the Agency’s current thinking on approaches for classifying products as drugs and devices, and on certain additional product classification issues, such as the request for designation (RFD) process. The guidance combines and finalizes two draft guidance documents from 2011:
- Classification of Products as Drugs and Devices and Additional Product Classification Issues (available here), and
- Interpretation of the Term “Chemical Action” in the Definition of Device Under Section 201(h) of the Federal Food, Drug, and Cosmetic Act (available here).
The final guidance focuses particularly on whether a product should be classified as a drug or device, and clarifies in a footnote that the discussion of the classification of products “is also relevant to classification of the constituent parts of a combination product.” Thus, the guidance may provide insight into the Agency’s current thinking for designation of the primary review center for the review of combination products.
The final guidance does not include, however, the draft guidance’s discussion of intercenter agreements and prior Agency classification determinations. In the Federal Register notice, FDA explains that it reconsidered inclusion of content on the status of prior Agency classification determinations in light of comments it had received. In particular, FDA states that it “has had limited experience with reevaluating classification determinations” and that this “can raise a variety of complex scientific and regulatory questions.” Therefore, FDA “concluded that it is not appropriate to address the topic further in guidance at this time,” but that it will “address the issue on a case-by-case, fact-specific basis as needed.”
In the final guidance, FDA states that, “conceptually,” all FDA-regulated medical products could be drugs unless they meet the more restrictive device definition. Under section 201(h) of the Federal Food, Drug, and Cosmetic Act, a device must be “an instrument, apparatus, implement, machine, contrivance, implant, in vitro reagent, or other similar or related article, including any component, part, or accessory,” and “does not achieve its primary intended purposes through chemical action within or on the body of man or other animals and … is not dependent upon being metabolized for the achievement of its primary intended purposes.” FDA, therefore, provides its current thinking on the following terms in the “device” definition:
- “Similar or related article”: Products in liquid, semi-liquid, gel, gas, or powder form may be classified as devices as long as they also satisfy the remainder of the device definition, including the chemical action exclusion. The final guidance includes a new example of a product that could be a “similar or related article”: liquids used to clean either surgical instruments or contact lenses.
- “Primary intended purpose”: Products that have chemical action may be classified as devices as long as they do not achieve their primary intended purposes through that chemical action. The final guidance does not include the draft guidance’s more controversial language stating that a product would not be a device if it depended “even in part” on chemical action within or on the body of man to achieve “any one of its primary intended purposes.” Nor does the final guidance include the draft guidance language explaining that a product with multiple therapeutic purposes, each of which would be a “primary intended purpose,” would not be a device “if it achieves any one of these primary intended purposes through chemical action within or on the body of man.”
The guidance includes two new examples of products that do not achieve their “primary intended purpose” through chemical action: (1) a hip joint replacement implant that restores movement and also elicits a foreign body response, and (2) an absorbable suture that rejoins tissue and also is resorbed by the body through chemical action.
- “Chemical action”: Products exhibit “chemical action” if they “interact at the molecular level with bodily components (e.g., cells or tissues) to mediate (including promoting or inhibiting) a bodily response, or with foreign entities (e.g., organisms or chemicals) so as to alter that entity’s interaction with the body.” The final guidance states that “this type of interaction is consistent with the term ‘pharmacological action’ as that term is generally understood in the medical field,” and so uses the two terms interchangeably. The final guidance clarifies that the “mere exchange of non-chemical energy (e.g., electromagnetic or thermal energy) between a product and the body would not constitute ‘chemical action.’”
- “Within or on the body”: FDA did not provide guidance on its interpretation of “within or on the body” in its draft guidances. In the final guidance, FDA explains that it considers this term generally straightforward and states that the chemical action occurs within or on the body if it “is occurring inside the body or on the surface of the body.”
FDA provides two examples of chemical action occurring “within or on the body”: (1) chemical action of an orally ingested pill or tablet of decongestant, and (2) chemical action of a spray or cream for treatment of dermatitis when applied to the skin. FDA also provides two examples of chemical action not occurring “within or on the body”: (1) chemical action occurring solely within a kidney hemodialysis machine, and (2) chemical action of a transport solution to preserve a donor organ for transplantation while in an organ transport container.
The final guidance does not provide further explanation of FDA’s device exclusionary clause that a device “is not dependent upon being metabolized for the achievement of its primary intended purposes,” because, the Agency states, this clause less frequently has been at issue in classification determinations.
The final guidance also includes additional examples of medical products that do notachieve their primary intended purposes through chemical action within or on the body (i.e., medical products that could be classified as devices). These include, among other examples: (1) gold nanoparticles that transfer heat to surrounding cells or tissue to treat cancer, (2) cryosurgery for wart removal, and (3) polymethylmethacrylate used as a temporary bone spacer. The final guidance does not include certain examples that were included in the draft guidance of medical products that doachieve their primary intended purposes through chemical action within or on the body (i.e., medical products that could be classified as drugs). These draft guidance examples include: (1) epsom salts that mediate a bodily response through intermolecular forces by influencing the diffusion of water, and (2) saline nasal spray that clears the nasal passage by dissolving encrusted foreign material.
In a new Frequently Asked Questions section, FDA also provides a new example of how the proposed use or indication of a product can affect its classification: a vaginal product that is intended solely to facilitate ease and comfort during sexual intercourse through lubrication that decreases friction may be classified as a device; the same product intended to alter pH, control odor, or prevent infection through chemical action, however, can be classified as a drug.