For me, Pred was starting to be less effective and that's why I started Humira. So it was easy to tell it was the Humira doing the heavy lifting when I started getting relief from my classic UC symptoms.
Your question is a good one though.
Unfortunately I don't know the answer.
M, 32, DX Sept 2009
Sulfasalazine worked for 6 years. Current flare for 2 years.
4g Sulfasalazine, 1g Canasa, 65mg iron supplement
Paleo/SCD based diet
Several months into Humira. So far so good.