Predicate Device Strategy: How FDA Reads Predicates, Reference Devices and Indications

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The 510(k) pathway is usually the fastest route to market for a moderate-risk device, but only if the predicate strategy holds up. A predicate FDA won't accept can mean new testing, a different predicate or a De Novo request, each adding time and cost after a company has planned around a clearance date.

Predicate strategy involves more than finding a similar device. FDA's substantial equivalence guidance sets rules on how many predicates a submission can use, what a reference device can and can't do, and when a change in indications for use becomes a new intended use. A predicate argument can be checked against those rules directly.

What Substantial Equivalence Requires

A new device is substantially equivalent to a legally marketed predicate if it has the same intended use and either the same technological characteristics or different ones that don't raise different questions of safety and effectiveness, and the information submitted shows it is as safe and effective. Any legally marketed class I or class II device can serve as a predicate, except one removed from the market at FDA's initiative or found misbranded or adulterated by a court.

One Predicate, or Several

FDA encourages a single predicate. A submission can use multiple predicates in some situations, for example when a new device combines features from predicates that share the same intended use, or seeks more than one indication for use under the same intended use. When it does, FDA recommends naming a primary predicate: the one with indications for use and technological characteristics most like the new device.

Reference Devices Are Not Predicates

A reference device is a legally marketed device cited for scientific or technical information, such as a test method, to help address a new technological characteristic. FDA's guidance says a reference device isn't a predicate and can't be used to establish the same intended use or the technological comparison; it can only support the later question of whether the methods and data show the device is as safe and effective.

Indications for Use and Intended Use

A device is cleared for the indications for use stated in its 510(k), and those indications must fall within the predicate's intended use. Indications can differ from the predicate's without creating a new intended use. Under FDA's guidance, only a change in indications that raises different questions of safety and effectiveness, so that a meaningful comparison with the predicate isn't possible, is a new intended use, and a new intended use puts the device outside the 510(k) program.

Finding and Checking Predicates

A practical starting point is the device's product code: searching FDA's 510(k) database, or its De Novo database, by product code shows devices of the same type and their clearance histories. For each candidate, check the clearance date, the cleared indications for use, the classification regulation and any recalls. Older clearances can still serve as predicates, but they often come with little public information to compare against, which can make substantial equivalence harder to show.

FDA's September 2023 draft guidance on predicate selection adds best practices: predicates cleared using well-established methods, meeting or exceeding expected safety and performance, and without unmitigated use-related or design-related safety issues or a design-related recall.

Questions for a Diligence Read

• Has the company named a primary predicate, and does it share the new device's intended use?
• Does any part of the argument rely on a device with a different intended use, in effect a split predicate?
• Are cited reference devices used only for methods and data, or are they standing in for a predicate?
• Do the proposed indications for use fall within the predicate's intended use?
• Does the predicate meet FDA's draft best practices, and has FDA weighed in through a Pre-Submission, which carries no FDA user fee?
• How do the indications the company expects to be cleared fit its reimbursement and commercial plan?

Bottom Line

Predicate strategy decides more than the review: the cleared indications shape labeling, marketing and reimbursement. FDA's rules on multiple predicates, reference devices and intended use are specific and published, so a diligence read can test a company's predicate argument against them.