Regent, and Radisson before them, have always chartered cruises. If, in fact, this cruise was canceled more than a year in advance there are no "deviation fees" paid and, in fact, no paid or frequent flyer airline tickets purchased. Only cost could be insurance which, as pcardad explained, can be transferred to a future trip.
Now, those occasional "last minute" charters do get me angry; hopefully more than $250pp in that case.
Marc