Extremely unlikely. I have a '19 Sirrus X Comp carbon (now the X 5.0 -- same frameset). 38s are stock. There is not an awful lot of clearance above that, and the 'X' frameset may ( I don't know) have slightly more clearance than the front-derailleur framesets (non-X).

I do know that one poster in this thread fit 42s to an X frameset; there are pics if you look through the thread. Clearance is very tight with that width. 45s would, if they fit at all, be silly-close clearance. If you want a bike that fits 45s, I'd look elsewhere.