Page 49 - Biomedical Engineering and Design Handbook Volume 2, Applications

28 MEDICAL DEVICE DESIGN

(ii) A device for which insufficient information exists to determine that the controls referred to in
clause (i) are sufficient to provide reasonable assurance of the safety and effectiveness of the
device or to establish special controls to provide such assurance, but because it—
(I) is not purported or represented to be for a use in supporting or sustaining human life or for
a use which is of substantial importance in preventing impairment of human health, and
(II) does not present a potential unreasonable risk of illness or injury, is to be regulated by the
controls referred to in clause (i).
Id.

Class I includes a myriad of medical supplies and low-risk devices. This is where FDA has classi-
fied the toothbrushes discussed above. Everything from bedpans to Q-tip swabs is found in this class.
As Fig. 2.3 shows, Congress chose a level of marketing clearance requirements and control based
upon the perceived risk.
At the high end of risk, Congress created the Premarket Approval (PMA) process. This was to be
the route to market for devices in Class III. FDA was instructed to call for PMAs on all devices in
Class III or downclass them to Class II. The downclass procedure was so complex that FDA did not
want to use up vast resources on downclassing. They immediately called for PMAs on what they
viewed as the most serious Class III devices but left some devices in Class III without PMAs. To this
day, there are lingering devices in Class III that do not require a PMA.
At the opposite end of the risk spectrum is Class I. Congress believed this class needed minimal
control. The big question was what to do with the vast middle area. Congress believed that current
devices were performing adequately, and that there was no need to rashly require a marketing clear-
ance for everything on the market, so Congress grandfathered in devices that were already on sale at
the time of the Medical Device Amendments in 1976. There are still devices on sale today that were
grandfathered in.
The next question was what to do if another company wanted to produce a product like the ones
grandfathered in. It would not be fair to allow the first company to sell the product, but not allow
follow-ons. Therefore, Congress created the 510(k) process, which got its name from its section of
FDCA. Section 510(k) said that if you wanted to sell a device substantially equivalent to one on the
market before 1976, you just had to notify FDA. If FDA did not tell you within 90 days that you
could not sell your device on the market, you could proceed and market. New products were to go
automatically into Class III, until FDA acted to downclass them.
It did not take FDA long to realize that this was an impractical scheme. If Section 510(k) were
read too narrowly, any improvements in medical devices would end up in Class III. It would take
enormous resources to process PMAs on new products and it would be too expensive to downclass
them. The FDCA required that FDA write a performance standard before moving a device out of
Class III and into Class II. FDA never did this.
Instead FDA rethought the 510(k) process. FDA turned the 510(k) process into a de facto
approval process, while still calling it notification. If FDA determined that a device belonged in class II,
even if it was a technological advancement, it worked to find a predicate device to find the device
equivalent to. It never required the performance standards mentioned in the statute. The process gen-
erally worked. Finally, in 1990, Congress modified the FDCA to remove the need for performance
standards and to adopt FDA’s definition of substantial equivalence.

2.8 PREMARKET APPROVAL (PMA)

A PMA is a detailed scientific review of a product. As discussed above, this is required for all new
Class III products. The FDA is required by statute to find, based upon valid scientific evidence, that
the device is safe and effective for the use for which it is labeled.
Remember that the labeling is of paramount importance. For example, take a device that is
already on the market as a Class II device under general use labeling, such as an ablation device; if