How long is the FDA 510k review timeline after acceptance?

## How Long is the FDA 510(k) Review Timeline After Acceptance? Once a 510(k) submission for a new Class II device, such as a novel orthopedic implant or diagnostic software, successfully passes the FDA’s Refuse-to-Accept (RTA) screening, the agency’s goal is to conduct a substantive review within 90 days. However, this 90-day target is often misunderstood and does not represent 90 continuous calendar days. The total time to a final decision can be significantly longer due to mechanisms that pause the review clock. The most common reason for a delay is an Additional Information (AI) request, which the FDA issues when a reviewer needs clarification or has questions about the data, testing, or documentation provided. When an AI request is sent, the FDA places the submission on hold, stopping the 90-day clock until the sponsor submits a complete response. This "stop-the-clock" mechanism is a critical factor for sponsors to understand when developing realistic project timelines and planning for commercial launch. ### Key Points * **The 90-Day Goal:** The FDA’s goal is to make a final decision on a 510(k) submission within 90 FDA days. This is a performance goal, not a guaranteed timeframe. * **The Review Clock Can Pause:** The 90-day review clock is not continuous. It stops whenever the FDA issues an Additional Information (AI) request and does not restart until a complete response is submitted by the sponsor. * **Sponsor Response Time is Not Counted:** The time a sponsor takes to gather data and formulate a response to an AI request, which can range from weeks to months, is not part of the 90 FDA days. * **Multiple AI Rounds are Possible:** For complex submissions, the FDA may issue more than one AI request, leading to multiple holds and extending the total calendar time significantly. * **Quality Submissions Reduce Delays:** A complete, well-organized submission that proactively addresses potential FDA questions is the most effective strategy for minimizing the likelihood of AI requests and achieving a decision closer to the 90-day target. ### Understanding the 510(k) "FDA Day" Clock After a 510(k) submission is accepted for review, the clock starts on the "FDA Day" count, which tracks the number of days the submission is actively under review by the agency. This is distinct from "calendar days." The process generally follows these steps: 1. **Substantive Review:** The FDA reviewer begins a detailed assessment of the submission to determine if the device is substantially equivalent to a legally marketed predicate device. 2. **Clock Stoppage (AI Request):** If the reviewer finds deficiencies or has questions, they will issue an AI request. At this point, the submission is placed on hold, and the FDA Day clock stops. The sponsor is typically given a set amount of time (e.g., 180 days) to respond. 3. **Sponsor Response:** The sponsor prepares and submits a complete response to the AI request. The time taken for this is entirely on the sponsor’s clock. 4. **Clock Restart:** Once the FDA receives the complete response, the FDA Day clock resumes from where it left off. Because of this stop-the-clock mechanism, a 510(k) review that takes 90 FDA days might span 150, 200, or even more calendar days from acceptance to final decision. ### Scenario 1: A Straightforward Review A manufacturer submits a 510(k) for a Class II software as a medical device (SaMD) that performs image analysis. The submission is well-organized, the predicate is clearly justified, and all performance testing is documented according to relevant FDA guidance documents. * **What FDA Will Scrutinize:** The FDA reviewer focuses on the software validation, the comparison to the predicate, and cybersecurity documentation. * **Outcome:** Because the submission is complete and the evidence is clear, the reviewer has no major questions. The review proceeds without any AI requests. The sponsor receives a final decision of Substantial Equivalence (SE) approximately 90-100 calendar days after RTA acceptance. ### Scenario 2: A Complex Review with an AI Request A company submits a 510(k) for a Class II orthopedic implant that uses a novel surface technology intended to improve integration. While the core implant design is similar to a predicate, the new material raises questions. * **What FDA Will Scrutinize:** The reviewer focuses heavily on the biocompatibility, mechanical strength, and shelf-life testing related to the new surface technology. They find that the provided biocompatibility data does not fully address the potential long-term effects. * **Outcome:** On FDA Day 65, the FDA issues an AI request asking for additional biocompatibility test results and a more detailed chemical characterization of the surface. The clock stops. The sponsor requires 75 calendar days to conduct the additional testing and prepare a comprehensive response. Once the response is submitted, the FDA clock restarts at Day 65. The FDA completes the remaining review, and the sponsor receives an SE decision. The total calendar time from acceptance to decision is over 160 days (65 FDA days + 75 sponsor days + 25 remaining FDA days). ### Strategic Considerations and the Role of Q-Submission The most effective way to manage the 510(k) review timeline is to minimize the risk of significant AI requests. A key strategy for achieving this is early engagement with the FDA through the Q-Submission program. By submitting a Pre-Submission (Pre-Sub), a sponsor can present its testing plan, predicate rationale, and any novel aspects of the device to the FDA before formally submitting the 510(k). This process allows the sponsor to get targeted feedback directly from the agency, clarify expectations, and identify potential review issues ahead of time. Addressing these points proactively can lead to a more complete and robust 510(k) submission, reducing the likelihood of the review clock being stopped for an AI request. ### Key FDA References - FDA Guidance: general 510(k) Program guidance on evaluating substantial equivalence. - FDA Guidance: Q-Submission Program – process for requesting feedback and meetings for medical device submissions. - 21 CFR Part 807, Subpart E – Premarket Notification Procedures (overall framework for 510(k) submissions). ## How tools like Cruxi can help Navigating the complexities of the 510(k) process requires meticulous planning and organization. Tools like Cruxi can help teams structure their submission narrative, manage evidence and documentation, and align their strategy with regulatory requirements found under 21 CFR and FDA guidance documents. By centralizing regulatory intelligence and submission content, these platforms can help ensure that all necessary components are addressed, potentially reducing the risk of easily avoidable AI requests. 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.