Heard this on this podcast. Second half of the show, a doctor from a Centers of Excellence mentions that best results are had when you are treated within 12 months of the onset of symptoms.
The doctor also lists his preferred treatments as IVIg, prednisone, and then PE.
http://paulchristomd.com/the-mystery-of-chronic-inflammatory-demyelinating-polyneuropathy-cidp/?utm_source=twitter&utm_medium=twitterpage&utm_content=radio&utm_campaign=evergreen