In Shulchan Aruch OC 334:21 it is established that holy scripture written by a pagan should be burnt,
האפיקורסים דהיינו האדוקים בעבודת כוכבים וכן מומרים לעבודת כוכבים שכתבו להם כתבי הקודש אין מצילים אותם ואף בחול שורפן עם האזכרות שבהן
According to those who maintain that Christianity is considered idol worship (AZ), must one burn nowadays a bible that was written by a christian since it was written by a pagan? Is there any reason why this law would not apply nowadays?
Update: In YD 281:1 the same Halacha is repeated but there we find a distinction between an אפיקורוס and a גוי; wherein the books of the former must be burned but the books of the latter only need to be hidden (גניזה). If we can clarify the difference between the two terms then we could easily determine in which category Christians--nowadays--fall into and whether their books need to be burnt at all! This will definitely shed some light on this complex law.