polymorph it into something that doesn't have Regeneration
Gerion of Mercadia said:The wording inside the regeneration ability is a bit "fuzzy" when it comes to this, because while it states a CDG needs to deal "lethal damage" a CDG attempt as I understand it never dealt damage - it was a straight fortitude save or die...
I am unsure if the now turned to stone creature would still have regeneration(Ex). Same goes for Polymorphing it.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.