What is the FDA review timeline for a De Novo classification request?

## Understanding the FDA De Novo Review Timeline: MDUFA Goals vs. Total Time to Decision For novel, low-to-moderate risk medical devices without a valid predicate, the De Novo classification pathway provides a route to market. A common point of confusion for sponsors involves projecting the timeline from submission to a final FDA decision. While the FDA operates under Medical Device User Fee Amendments (MDUFA) performance goals, which set targets for the number of "FDA days" to review a submission, this figure does not always represent the total calendar time a sponsor will experience. The concept of the "review clock" is critical. The MDUFA performance goal measures the time the submission is actively under review by the agency. However, if the FDA issues a request for additional information (AI), this review clock stops. It only restarts once the sponsor has submitted a complete response to the agency's questions. This period while the submission is "on hold" is not counted toward the MDUFA goal, but it adds to the overall "total time to decision." For startups and other organizations, accurately forecasting this total time is essential for business planning, securing financing, and managing stakeholder expectations. ### Key Points * **MDUFA Goal vs. Reality:** The FDA has a performance goal for reviewing De Novo requests, measured in "FDA days." This is the time the FDA actively spends on the submission and is not the same as total calendar time. * **The "Review Clock" Stops:** When the FDA issues a request for additional information (AI), the review clock is paused. The time a sponsor takes to prepare and submit a complete response does not count against the FDA's MDUFA goal. * **AI Requests Are Common:** Most submissions receive at least one AI request. Sponsors should anticipate this and factor the potential "on-hold" period into their overall project timeline. * **Sponsor Response Time is Key:** The duration of the clock stop is largely determined by how quickly and completely the sponsor can address the FDA's questions. This can range from weeks to several months. * **Total Time to Decision:** This is the full calendar time from submission to a final FDA decision, including any time the review clock was paused. It is almost always longer than the MDUFA performance goal. * **Early Engagement is Valuable:** Using the Q-Submission program to gain FDA feedback *before* submitting a De Novo request can help clarify requirements, reduce uncertainties, and potentially minimize the scope of future AI requests. ### Understanding the MDUFA Performance Goal ("FDA Days") Under the MDUFA framework, the FDA commits to performance goals for various submission types, including De Novo requests. The goal is to make a "MDUFA decision"—which includes granting the request, declining it, or issuing an AI letter—within a specific number of FDA review days. It is crucial to understand that this is not a guaranteed timeline for clearance or classification. Instead, it is a target for the agency to complete its review cycle. The clock begins on the day the FDA accepts the submission for substantive review and stops if and when the FDA requests additional information. For example, if the FDA issues an AI request after 80 days of review, the clock stops. It will only restart at day 81 once the sponsor provides a complete response to all questions raised in the AI letter. ### Why "Total Time to Decision" is Often Longer The primary reason the total time to decision exceeds the MDUFA goal is the issuance of an Additional Information (AI) request. This is a standard part of the interactive review process where the FDA seeks clarification or more data to complete its assessment. #### What Happens During an AI Request? 1. **Clock Stops:** The FDA issues an AI letter detailing the deficiencies or questions. At this point, the MDUFA review clock is paused. 2. **Sponsor Responds:** The sponsor is given a set period (typically 180 days) to respond. The length of this phase depends entirely on the complexity of the questions and the sponsor's ability to gather the necessary data, conduct testing, or formulate a comprehensive response. 3. **Clock Restarts:** Once a complete response is submitted, the FDA restarts the review clock. The agency then has the remaining days of its MDUFA goal to complete the review and issue a final decision. Because the time the submission is on hold can be significant, a De Novo request can easily take many months or even over a year from submission to final decision, even if the "FDA days" remain within the MDUFA target. ### Strategic Considerations and the Role of Q-Submission Sponsors can take proactive steps to manage their De Novo timeline and prepare for the interactive review process. The most effective tool for this is the Q-Submission program. By engaging with the FDA through a Pre-Submission (Pre-Sub) meeting, sponsors can present their device, testing strategy, and proposed controls before formally submitting the De Novo request. This dialogue can help: * **Align on Testing Requirements:** Clarify the performance data (bench, animal, clinical) that the FDA will expect. * **Refine General and Special Controls:** Propose and get feedback on the controls necessary to mitigate identified risks. * **Identify Potential Deficiencies Early:** Uncover and address potential review issues before they can lead to a lengthy AI clock stop. While a Q-Submission does not guarantee a faster review, it significantly de-risks the process by fostering early alignment with the agency, which can lead to a more complete and higher-quality initial submission. ### Key FDA references * FDA's Q-Submission Program guidance (provides details on the process for obtaining pre-submission feedback). * FDA's guidance on the De Novo Classification Process (outlines the general framework and requirements). * 21 CFR Part 807, Subpart E – Premarket Notification Procedures (general regulations applicable to certain premarket submissions). ### How tools like Cruxi can help Navigating the De Novo pathway requires careful organization of technical data, risk analysis, and regulatory arguments. Tools like Cruxi can help teams structure their submission, manage supporting evidence, and build a well-organized file that aligns with FDA expectations. By centralizing documentation and tracking requirements, sponsors can prepare more efficiently for FDA interactions and respond to AI requests in a more structured and timely manner. This article is for general educational purposes only and is not legal, medical, or regulatory advice. For device-specific questions, sponsors should consult qualified experts and consider engaging FDA via the Q-Submission program.