I'm very confident that the first thing most FDA workers would reply is more like 'what's Flucide?'
Followed by a question or two about what data has been collected.
I work in a lab-diagnsotic setting - and 'I don't know - yet' is regularly the correct answer. But is always followed by, or immediately preceeded by questions about what data has, and has not been collected.
We're quibbling about pointless semantics here. Stating that the FDA doesn't 'know' when they haven't bothered to look at data is chosing to look at an unknown and assume it is by definition going to be a negative. It could very well end up a positive.
What it is - is an unknown. And any FDA scientist worth his/her salary isn't going to give you an unqualified 'I don't know'.