This shouldn't cause too much of a problem with the CAA. I am currently in remission with Ulcerative Colitis and the CAA allow me to take double the amount of Asacol you are on and an immune system suppressant called Azathioprine.
I currently hold a class one medical with an as or with co pilot restriction and fly full time with an Airline.
Worth checking with the authority and yor Consultant before you start taking the new medication. You will find the CAA medical department very helpful and will do all that they can to keep you flying.
Please feel free to e-mail me.