How to choose the best predicate device for a new medical device?

Choosing the right predicate device is one of the most critical strategic decisions in preparing a 510(k) premarket notification. A well-chosen predicate forms the foundation of the substantial equivalence argument, streamlining the review process. Conversely, a poorly chosen predicate can lead to requests for additional information (AIs) or even a Not Substantially Equivalent (NSE) determination. Sponsors often face a choice between multiple potential predicates, each with trade-offs between its intended use, technological characteristics, and the amount of publicly available performance data. The core of the decision-making process revolves around demonstrating that a new device is as safe and effective as a legally marketed device. This involves a careful evaluation of how a new device compares to a predicate in terms of its intended use and technology. For a device with novel features, like a diagnostic catheter with a new sensor, the challenge is to find a predicate that provides a solid basis for comparison without introducing new questions of safety and effectiveness that cannot be resolved with performance data. ### Key Points * **Intended Use is Paramount:** The intended use of the new device and the predicate must be identical or very similar. This is the most critical element of a substantial equivalence argument, and significant differences are rarely accepted. * **Technological Differences Must Be Justified:** A device can have different technological characteristics than its predicate, but the sponsor must demonstrate that these differences do not raise new questions of safety and effectiveness. * **Performance Data Bridges the Gaps:** Bench, and sometimes animal or clinical testing, is essential to prove that a new device is at least as safe and effective as the predicate, especially when technological differences exist. * **A "Split Predicate" is Not Allowed:** A sponsor cannot "split" a predicate by claiming equivalence to one part of a device's intended use while ignoring another. The comparison must be to the predicate as a whole. * **Multiple Predicates Add Complexity:** While permissible, using one device as a predicate for intended use and another for technology (a "multiple predicate" approach) complicates the submission narrative and requires a very clear and convincing justification. * **Q-Submission De-Risks Your Strategy:** For novel technology, a borderline intended use, or a complex predicate strategy, engaging the FDA through the Q-Submission program is a valuable tool to get feedback and align on the approach before filing the 510(k). ### Understanding the Core of Substantial Equivalence The concept of substantial equivalence is defined in FDA regulations under 21 CFR. A device is considered substantially equivalent (SE) if, in comparison to a predicate, it: 1. Has the **same intended use** as the predicate; and 2. Has the **same technological characteristics** as the predicate. Alternatively, a device can be found SE if it has the **same intended use** but **different technological characteristics**, provided that the submission contains information, including performance data, demonstrating that the device is at least as safe and effective as the legally marketed predicate and does not raise different questions of safety and effectiveness. ### Evaluating Predicate Options: A Strategic Framework When faced with multiple potential predicates, sponsors must weigh the strengths and weaknesses of each option. Let's consider the scenario of a new Class II diagnostic catheter with a novel sensor. #### Scenario 1: Same Intended Use, Older Technology A predicate with an identical intended use statement but based on older technology is often a strong starting point. * **What FDA Will Scrutinize:** The primary focus will be on the new technological characteristics. The sponsor must thoroughly characterize the differences and assess whether they introduce new or increased risks. * **Critical Performance Data to Provide:** A comprehensive battery of non-clinical performance testing is required. This testing should directly compare the performance of the new device against the predicate (or a well-established performance standard) to demonstrate that the new technology performs as well as, or better than, the older technology without compromising safety. #### Scenario 2: Similar Technology, Different Intended Use This is generally the most challenging and highest-risk predicate strategy. * **What FDA Will Scrutinize:** Any difference in the intended use statement will receive intense scrutiny. FDA guidance emphasizes that the intended use must be the same. Even seemingly minor variations in the patient population, disease state, or clinical environment can be considered a different intended use, which would make the device not substantially equivalent. * **Critical Performance Data to Provide:** While technology may be similar, if the intended use is different, no amount of performance data can bridge that gap within a 510(k). This scenario often requires a De Novo classification request or a PMA. #### Scenario 3: Good Apparent Match, Limited Public Data A recently cleared device may seem like an ideal predicate, but its 510(k) summary may lack the detailed performance data needed for a robust comparison. * **What FDA Will Scrutinize:** The sponsor's methodology for establishing the predicate's performance characteristics. If the data isn't public, the sponsor must justify the performance standards used for the comparison. * **Critical Performance Data to Provide:** The sponsor may need to acquire and test the predicate device to establish baseline performance data. The submission must include a clear rationale for the testing performed and how it demonstrates that the new device is at least as safe and effective as the predicate. ### The Multiple Predicate Strategy In some cases, a sponsor may use more than one predicate device to support a substantial equivalence claim. This is typically done when a new device incorporates features from different existing devices. For example, a sponsor might reference one predicate for its identical intended use and another for its similar technological principles of operation. However, this strategy must be executed carefully. It increases the complexity of the submission, requiring a clear narrative that explains the role of each predicate and synthesizes the evidence into a single, cohesive argument for substantial equivalence. It is crucial to avoid a "split predicate" argument, where the new device is compared to only a portion of a predicate's features or intended use. ### Strategic Considerations and the Role of Q-Submission Choosing a predicate is not merely a technical exercise; it is a fundamental regulatory strategy. An aggressive choice may shorten development timelines but carries a higher risk of rejection, while a conservative choice may require more extensive testing but offer a more predictable path to clearance. For any complex situation—such as a device with novel technology, a potential new indication, or reliance on a multiple predicate strategy—the Q-Submission program is an invaluable resource. Submitting a Pre-Submission (Pre-Sub) allows a sponsor to present their predicate rationale and testing plan to the FDA and receive written feedback. This early engagement can identify potential issues, clarify FDA's expectations, and significantly de-risk the final 510(k) submission. ### 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 predicate selection requires meticulous research and organization. Regulatory intelligence platforms can help sponsors efficiently search FDA databases, analyze predicate 510(k) summaries, and track key data points like intended use statements and technological characteristics. Tools like Cruxi can help structure this comparative analysis, manage supporting documentation, and build a clear, data-driven rationale to support the final 510(k) submission. 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.