Someone who works in statistics in the pharmaceutical industry (but prefers to remain anonymous) sent me this update to our discussion on the differences between approvals of drugs and medical devices:

The ‘substantial equivalence’ threshold is a very outdated. Basically the FDA has to follow federal law and the law is antiquated and leads to two extraordinarily different paths for device approval.

You could have a very simple but first-in-kind device with an easy to understand physiological mechanism of action (e.g. the FDA approved a simple tiny stent that would relieve pressure from a glaucoma patient’s eye this summer). This device would require a standard (likely controlled) trial at the one-sided 0.025 level. Even after the trial it would likely go to a panel where outside experts (e.g.practicing & academic MDs and statisticians) hear evidence from the company and FDA and vote on its safety and efficacy. FDA would then rule, consider the panel’s vote, on whether to approve this device.

On the other hand you could have a very complex device with uncertain physiological mechanism declared equivalent to a device approved before May 28, 1976 and it requires much less evidence. And you can have a device declared similar to a device that was similar to a device that was similar to a device on the market before 1976. So basically if there was one type I error in this chain, you now have a device that’s equivalent to a non-efficacious device. For these no trial is required, no panel meeting is required. The regulatory burden is tens of millions of dollars less expensive and we also have substantially less scientific evidence.

But the complexity of the device has nothing to do with which path gets taken. Only it’s similarity to a device that existed before 1976.

This was in the WSJ just this morning.

You can imagine there was nothing quite like the “NanoKnife” on the market in 1976. But it’s obviously very worth a company’s effort to get their new device declare substantially equivalent to an old one. Otherwise they have to spend the money for a trial and risk losing that trial. Why do research when you can just market!?

So this unfortunately isn’t a scientific question — we know what good science would lead us to do. It’s a legal question and the scientists at FDA are merely following U.S. law which is fundamentally flawed and leads to two very different paths and scientific hurdles for device approval.