Speaking very generally, class 3 medical devices require clinical trials and post market reporting, similar to the way new drugs are approved. Most class 2 devices do not require post-market surveillance and do not have the pre-market human trials requirement of class 3.
Class 2 devices represent the largest share of new devices coming to market each year - for example, in fiscal year 2013, the FDA cleared 2,895 class 2 devices and approved 44 class 3 devices. Class 2 and 3 devices and diagnostics have to follow FDA quality systems regulations, aka 21 CFR 820, current Good Manufacturng Practice (cGMP).
Class 1 devices are considered low risk, yet need to be manufactured according to cGMP;. The manufacturer must list and register all devices manufactured in the USA or in foreign countries. Manufacturers and initial importers/distributors also must keep a complaint system for class 1 devices.
Class 3 devices are “approved” by the FDA after a process that includes a premarket application (PMA) including clinical trial data and specific post-market reporting requirements. Class 2 devices are "cleared" by the FDA after review of the premarket notification, aka "510(k)".
Tips and Hints for a positive medical device commercialization path:
Recognize that this like running a marathon – sprinting in parts will just lead to hitting the wall near the finish line. And the finish line may very likely move.
Take advantage of the Pre-Submission process. This process allows you to perform much of the front-end work before paying the application fee and starting the clock, including writing the draft 510(k), and proposing test protocols and data formats. If you identify every single indication for use and every version of the device, you can submit a bundled 510(k) and only pay one fee when the time comes.
Work with test labs to make sure your protocols are aligned with standards and regulations from FDA, ISO, ANSI/AAMI, USP, ASTM, and the EU MDR. Also ensure that the test suites are done sequentially – if something fails then you are not on the hook for a lot of other tests if you have to revise the device. The test labs can be really helpful in suggesting alternatives if a certain protocol is expensive.
FDA has a manufacturer database that shows manufacturer inspections and warning letters. Look up everything on competing products and especially the predicate device if doing a 510(k). Make sure not to repeat mistakes. FDA data is fast and free to look up.
Get a wide variety of people to identify hazards and evaluate risks for the device. Do not rely on engineers and quality/regulatory to identify assembly issues, logistics issues or clinical use issues. The more varied the group the better your device will be. At a minimum you will need a user of the device, the engineer(s), production and packaging input.
Dry run the production line and packaging processes before submitting a 510(k) – it will cost you far less money to identify problems and correct them at this stage. This is especially crucial if using contract manufacturers – if they are offshore, get on the plane now!