Key Takeaways
- De Novo is the right pathway for novel Class I or Class II devices—when no legal predicate exists, but general and special controls can reasonably assure safety and effectiveness.
- Two submission routes exist: file directly if no predicate exists, or submit within 30 days of a 510(k) Not Substantially Equivalent (NSE) decision.
- A strong request is built on risk-benefit evidence, performance data, labeling, and special controls that address every identified health risk.
- Know the difference between pathways: 510(k) requires substantial equivalence to a predicate; De Novo establishes a brand-new classification; PMA applies to high-risk Class III devices.
- A granted De Novo request immediately authorizes marketing and designates the device as a predicate—opening the door for follow-on manufacturers to pursue 510(k) clearance.
What Is the De Novo Pathway?
The De Novo pathway is a regulatory classification mechanism under section 513(f)(2) of the Federal Food, Drug, and Cosmetic Act (FD&C Act). It provides a route to Class I or Class II marketing authorization for novel medical devices where no legally marketed predicate device exists, but where general controls—or general and special controls combined—offer reasonable assurance of safety and effectiveness. Other premarket routes require demonstrating substantial equivalence to an already-classified device. The De Novo process is different: it is fundamentally risk-based. The FDA evaluates and classifies the device according to its actual risk profile, not by comparison to an existing product.
The pathway was established in 1997 under the Food and Drug Administration Modernization Act (FDAMA), which added section 513(f)(2) to the FD&C Act. Before this, novel devices that received a Not Substantially Equivalent (NSE) determination through a 510(k) submission were automatically placed into Class III—requiring full Premarket Approval (PMA), regardless of whether their actual risk profile warranted it. The De Novo process was created to address exactly this inefficiency: to avoid unnecessary expenditure of FDA and industry resources on devices whose risks could be adequately managed through general or special controls.
The pathway expanded further in 2012. Section 607 of the Food and Drug Administration Safety and Innovation Act (FDASIA) amended section 513(f)(2) to introduce a second submission option. Sponsors no longer had to go through the 510(k) process first if no legally marketed predicate existed. The result: two distinct routes under the De Novo pathway.
- Option 1: After receiving an NSE determination on a 510(k) submission, a sponsor may request De Novo classification within 30 days of receiving notice of that determination.
- Option 2: A sponsor who determines that no legally marketed predicate device exists may submit a De Novo request directly, without first filing a 510(k).
The outcome of a successful De Novo request carries significant regulatory weight. The device receives marketing authorization as a Class I or Class II device and is immediately designated as a predicate device. Future manufacturers of the same device type can then use it as the basis for their own 510(k) submissions—without filing a separate De Novo request or PMA. That predicate designation takes effect upon granting, with no statutory waiting period. The De Novo process, in this way, functions as both a marketing authorization tool and a regulatory reference point for entire categories of novel devices entering the market.
Which Medical Devices Qualify for De Novo Classification?
Eligibility for De Novo classification is specific. The device must be of a novel type—one for which no legally marketed predicate exists—and general controls alone, or general and special controls, must be sufficient to provide reasonable assurance of safety and effectiveness. Practically speaking, this covers devices that fall outside any existing classification regulation in the Code of Federal Regulations. These devices are automatically placed into class III under section 513(f)(1) of the FD&C Act—not because the risk profile demands it, but simply because no regulatory precedent exists for that device type.
For devices that have already gone through 510(k) review, the FDA will consider a De Novo request only when the Not Substantially Equivalent (NSE) determination resulted from one of three specific causes:
- No identifiable predicate device
- A new intended use
- Different technological characteristics that raise different questions of safety and effectiveness
This distinction matters. Devices found NSE solely because the submitted performance data was inadequate to demonstrate substantial equivalence are generally ineligible. The De Novo process is reserved for truly novel devices—not those that simply fell short of evidentiary standards within an existing regulatory category.
Devices that already fall under an existing classification regulation or an approved PMA are also ineligible. The applicable mechanism for those is reclassification under section 513(e) or 513(f)(3) of the FD&C Act. The De Novo definition in medical device regulation is therefore bounded: it applies only where no prior regulatory classification for that device type exists.
Beyond the absence of a predicate, the requesting party must demonstrate that the device’s probable benefits outweigh its probable risks—and must identify all known health risks along with proposed mitigations through general or special controls. The FDA will decline a De Novo request under the following conditions:
- General controls, or general and special controls, are insufficient to provide reasonable assurance of safety and effectiveness.
- The submitted data are insufficient to determine whether such controls can provide that assurance.
- The probable benefits of the device do not outweigh the probable risks.
If the FDA declines, the device remains in class III. Full premarket approval is then required before it can be legally marketed.
De Novo vs. 510(k) vs. PMA: Choosing the Right Pathway
Three premarket pathways exist for medical devices seeking FDA marketing authorization: the 510(k) premarket notification, the De Novo classification request, and the Premarket Approval (PMA) application. Each pathway corresponds to a different risk tier and a different evidentiary standard. The regulatory outcome of each differs in both terminology and legal effect.
A 510(k) results in a device being cleared for marketing. It applies to Class I and Class II devices for which a legally marketed predicate already exists. The applicant must demonstrate substantial equivalence—showing that the new device shares the same intended use and either the same or non-safety-raising technological characteristics as the predicate.
A PMA, by comparison, results in approval. It applies to Class III devices that support or sustain human life, present unreasonable risks of injury, or are of substantial importance in preventing health impairment. General and special controls alone are insufficient for Class III devices, requiring an independent demonstration of safety and effectiveness—typically backed by robust clinical data.
The De Novo process results in a grant of marketing authorization. It occupies the regulatory space between these two pathways, serving novel low-to-moderate-risk devices that have no predicate.
The table below summarizes the principal distinctions:
| Feature | 510(k) | De Novo | PMA |
|---|---|---|---|
| Device risk class | Class I / II | Class I / II | Class III |
| Predicate required | Yes | No | No |
| Standard of review | Substantial equivalence | Risk-based classification | Independent safety and effectiveness |
| Regulatory outcome | Clearance | Grant | Approval |
| Creates new predicate | No | Yes | No |
| Mean FDA review time | 150 days | 338 days | 399 days |
Review timelines reflect the evidentiary demands of each pathway. The FDA mean decision time for De Novo requests was 338 days, compared to 150 days for 510(k)s and 399 days for PMAs over a similar observation period. De Novo decision times were, on average, 2.3-fold longer than 510(k) review times and roughly 15% shorter than PMA review times. That gap is significant—and worth factoring into your planning timeline.
A key structural difference is predicate creation. A granted De Novo request establishes a new product classification and designates the subject device as the first predicate for its device type. Subsequent manufacturers of substantially equivalent devices may then use the 510(k) pathway, referencing the De Novo-classified device as their predicate. The 510(k) applicant carries no such burden—it draws on an already-established regulatory category. The PMA applicant, different from both, obtains approval specific to that device and does not create a predicate available for 510(k) use.
The bottom line: pathway selection isn’t just a regulatory formality. It determines your evidentiary burden, your timeline, and whether your device ultimately creates a regulatory opening for others in the market.
How Does the FDA De Novo Review Process Work?
Choosing Your Submission Route
The starting point depends on where you are in the process. Sponsors who received a Not Substantially Equivalent (NSE) determination on a prior 510(k) must submit the De Novo request within 30 days of that decision. Sponsors who have already determined that no predicate exists can submit directly—no prior 510(k) required. Both routes go to the FDA’s Center for Devices and Radiological Health (CDRH).
The route matters, but so does the substance of what you submit.
What the Request Must Include
Each De Novo request requires a clear description of the device and its intended use, a thorough risk assessment covering all probable risks, and proposed special controls that directly address each of those risks. The sponsor must make the case that probable benefits outweigh probable risks—and that general controls alone, or combined with special controls, provide reasonable assurance of safety and effectiveness.
Beyond the risk-benefit argument, the submission must also include:
- Performance testing data supporting safety and effectiveness claims
- Proposed labeling
- A suggested classification regulation for the new device type
The evidentiary bar here is meaningful. The FDA is not simply evaluating one device—it is establishing a regulatory framework for an entire product category.
The FDA’s Two-Stage Review
Before substantive review begins, the FDA conducts an acceptance review to confirm the submission is administratively complete. Think of it as a gate check. If the submission clears that gate, the agency moves to a full safety and effectiveness review—evaluating the proposed risk controls, the classification recommendation, and all supporting data.
At this stage, the FDA may issue an interactive review request for additional information. When that happens, the review clock pauses until the sponsor responds. How quickly and thoroughly a sponsor addresses those requests can significantly influence the overall timeline.
Timelines and Fees
De Novo requests are subject to user fees under the Medical Device User Fee Amendments (MDUFA). The FDA’s stated review goal is 150 days for accepted submissions. In practice, the mean decision time has been recorded at 338 days. The gap reflects the complexity involved—establishing a new device classification where no regulatory precedent exists takes time, and the FDA’s review is correspondingly thorough.
The bottom line: plan for a longer timeline than the stated goal, respond to FDA information requests promptly, and build your submission around solid risk-benefit evidence from the outset.
What happens after FDA grants a De Novo request?
Class I or Class II classification and required controls
When the FDA grants a De Novo request, several regulatory consequences follow immediately. The device receives marketing authorization and must comply with all applicable regulatory controls. A new classification regulation for that device type is established, and the FDA publishes a Federal Register notice within 30 days of the granting decision. For class II devices, special controls are identified at the time of granting, not afterward, because these controls are necessary to reasonably assure safety and effectiveness. The FDA, as well as publishing the classification order, voluntarily generates a decision summary presenting the scientific evidence that formed the basis for the classification decision.
Use as a predicate for future 510(k) submissions
A device classified through the De Novo process becomes the first predicate for its newly established product code, available for use immediately, with no statutory waiting period imposed by the FD&C Act. Consequently, follow-on manufacturers of substantially equivalent devices may use the 510(k) pathway rather than submitting a separate De Novo request or PMA. Of 374 De Novo requests analyzed between 1997 and August 2023, 371 resulted in new product codes. Follow-on 510(k) applicants must, however, still comply with the special controls established at the time of the original De Novo grant.
The De Novo pathway allows novel, low-to-moderate-risk medical devices without a legally marketed predicate to receive marketing authorization as Class I or Class II devices.
Class II devices use general and special controls to manage risks. Class III devices require premarket approval (PMA) because those controls alone cannot provide reasonable assurance of safety and effectiveness.
A 510(k) submission demonstrates substantial equivalence to an existing predicate device. De Novo evaluates a novel device without a predicate and establishes a new classification that future substantially equivalent devices can use.
De Novo requests are subject to FDA user fees under the Medical Device User Fee Amendments. The applicable fee should be checked in the FDA’s current fee schedule.
The FDA’s standard review goal is 150 days for accepted submissions, but actual timelines can be longer. Historical data cited a mean decision time of 338 days, and requests for additional information can extend the process.