Devices

FDA Needs to Define ‘Substantial Equivalence’

David McFarland

— 2 min read
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[Commentary by Jim Dickinson] The recent exposure on this Web site of FDA 510(k) review corruption where favored companies’ devices get fast tracks to market while their competitors are slow-tracked or denied is testament to the need for an FDA definition of “substantial equivalence.” Since the term is the statutory peg on which the entire 48-year-old 510(k) program hangs, you might think such a definition would have been put in place long ago. If so, you’re sadly mistaken. Worse, the crucial term’s elasticity has let CDRH and its industry favorites huddle together and make “substantial equivalence” mean whatever the moment’s circumstances allow it to mean.

I’ve long been suspicious of the convenient elasticity in the 510(k) process and how it swiftly clears without fuss high-tech devices that bear a vague similarity to far simpler old devices cited as predicates. As if an MRI could be cleared under 510(k) because of its “substantial equivalence” to a 1940s era shoe-fitting fluoroscope! I exaggerate to make a point. The lack of a tight, explicit definition allowed review elasticity that could be expanded and contracted at will. As our recent exposé reported, Innovative Health Science’s (IHS) new and improved Insignis infusion pump has been blocked from the market as “not substantially equivalent” to earlier equivalent pumps on the market that were designed by the same engineer for exactly the same purpose.

By examples FDA gives on its Web site, the agency would seem to tacitly acknowledge that IHS’ device actually is substantially equivalent. Quoting from the 1990 Safe Medical Devices Act, it says a medical device “is substantially equivalent if, in comparison to a predicate it:

  • has the same intended use as the predicate; and
  • has the same technological characteristics as the predicate;
    or
  • has the same intended use as the predicate; and
  • has different technological characteristics and does not raise different questions of safety and effectiveness; and
  • the information submitted to FDA demonstrates that the device is as safe and effective as the legally marketed device.”

All of these conditions apply to the Insignis, but review elasticity allows CDRH to block it by adding extraneous criteria. So what is “substantial equivalence”? Believe it or not, but in the 1976 Medical Device Amendments Congress left that up to FDA to decide and the agency has never defined the term. With its customary urgency, it took 10 years from the amendments’ passage to issue formal guidance on the law, and a further 28 years to issue the current guidance – all without defining “substantial equivalence.”

In announcing the current version in 2014, the agency was unabashed in declaring: “The intent of this guidance is to identify, explain, and clarify each of the critical decision points in the decision-making process FDA uses to determine substantial equivalence.” The closest it comes to a definition of substantial equivalence is on its 39th and last page: “The following terms are defined for purposes of this guidance.” But substantial equivalence is not among those terms.

Clearly, the current elasticity in the 510(k) regulatory scheme at CDRH that allows corruption of its review process suits Center management and its favored firms just fine. Others, not so much.

And that being the case, since Congress seems currently unable to enact anything, commissioner Robert Califf should step into the breach and begin rulemaking to define substantial equivalence and codify its requirements in regulations.

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