George,
Welcome to the forum. It is always ok to ask.
BCG with Interferon seems to have helped me more than BCG alone. I am hopeful that it, and other treatments will prove effective against CIS.
Adding interferon did not increase my already major BCG side effects. Others report a wide range of side effects - from minor to strong - it seems to be very individual thing.
Is yours papillary or CIS ? How many total BCG treatments ?
The link below is to a compiled article by Dr. Michael O'Donnell with an over view of his thoughts on interferon. He considers adding Interferon to be a positive thing.
You can use the search box and type in key words such as "interferon", and also visit the files area, or simply post questions to the group. I found this site a real asset when first diagnosed. No doctors here - just other patients with our own experiences.
Best,
Jack
thomaschallenger.com/wp-content/uploads/2011/10/Mike-ODonnell-Protocol-long.pdf