I have not suffered from Colitis, but I know that we have several members here who have and I do hope that they respond to you.
I am sorry to hear that you are dealing with so much and have not really had any relief for quite a while. I understand your trepidation about Prednisone, especially if you did not tolerate it well before. Your are correct, there are other immunosuppressants that can be considered and I do hope that one of them works for you.
I wish you the very best and hope that you get some answers and relief soon.
Peace and Blessings