My understanding of it is, that it depends on case to case bases. It depends what your drug, device, or both intend on doing. Keep in mind, some risks may not appear in short term clinical trials. Or they may not be significant risk given the time frame to determine if they are significant. For example, they may not be considered significant risks at the time of reporting, but what about two years from the clinical trials? If clinical trials only show data for 1 year and declare it not significant risk but in practical use, the device or drug may show significant risk after 2 years of being exposed to the body environment. What happens than?

So to further push the discussion and briefly answer your question based on my understanding, I would depend on your case study, and data provided. In some cases, the FDA may require a longer term of research done to determine the risk.