Is it the leather, or the pages that smell? If it is the rather, there may be other options to just treat the binding. If the baking soda worked, then you could put the book in an airtight container with an open box of baking soda for a bit, rather than dusting the pages?

We have an antique maple- handled knife that has a slight check in the wood with the mold smell within. Both the leather and the handle smell. I've tried bleach, but the thing still smells musty. I will try other things, because the knife belonged to a family member, but at some point we will have to just toss it. :-/