Since Nilvadipine has never been submitted for approval in the USA, it seems unlikely that the FDA would have had anything to say about it.
Archer has already developed ARC031, Nilvadipine without the blood pressure lowering effect. However, it seems more likely that Rosk/Arch would move ahead with seeking clearance for the current formulation because Arc031 will likely have to undergo the full trial process which will take years, and besides they have found that Nilvadipine does not lower the blood pressure of those who do not have an elevated blood pressure.