FDA isn't holding up anything. The controlled containment imaging, controlled efficacy studies and the genotoxicity suggestions from FDA would have been anticipated and wrapped up years ago by competent management. Regarding genotoxicity, for all we know issue was raised in comments on first draft IDE application, and when MK finally responded over a year later with a 2nd draft, FDA found the response lacking?
In any event, until RDGL submits an IDE application for human trials, there's nothing for FDA to consider.